PHOTOMETRY AND POLARIMETRY NETWORK I. INTRODUCTION The narrow-band photometry of the Photometry and Polarimetry Network (PPN) grew out of a previous program of narrow-band photometry of comets carried out by M.F. A'Hearn and R.L. Millis. That program led first to the creation in 1979 of a working group on standard filters under the auspices of Commission 15 of the International Astronomical Union. Standard filters were defined and purchased with a grant from the U.S. National Science Foundation for a worldwide distribution. These activities were merged with those of the IHW when A'Hearn was selected as the PPN Discipline Specialist (Table I). Table I. Discipline Specialist Team for the Photometry and Polarimetry Network ________________________________________________________________________________ Team Member Affiliation Responsibility ________________________________________________________________________________ Michael F. A'Hearn Astronomy Program Discipline Specialist University of Maryland College Park, MD 20742 U.S.A. Vladimir Vanysek Department of Astronomy Discipline Specialist Charles University CZ-15000 Prague 5 Czechoslovakia Humberto Campins Astronomy Program Assistant Discipline University of Maryland Specialist 1982-84 Michael A. Feierberg Astronomy Program Assistant Discipline University of Maryland Specialist 1984-86 Uri Carsenty Astronomy Program Assistant Discipline University of Maryland Specialist 1986-88 Marek Wolf Department of Astronomy Assistant Discipline Charles University Specialist Wayne Osborn Physics Department Coordinator for Central Michigan University Standard Stars Mount Pleasant, MI 48859 U.S.A. David Edsall Astronomy Program Programmer University of Maryland Jason Meyer Astronomy Program Programmer University of Maryland Anne Raugh Astronomy Program Programmer University of Maryland Don Ingram Astronomy Program Technical Assistant University of Maryland Clare Ewald Astronomy Program Data Processing and University of Maryland Archiving Assistant John Macuk Astronomy Program Data Processing and University of Maryland Archiving Assistant Edith Stahl Astronomy Program Data Processing and University of Maryland Archiving Assistant Lyla Taylor Astronomy Program Data Processing and University of Maryland Archiving Assistant Melisa Walter Astronomy Program Data Processing and University of Maryland Archiving Assistant Margaret Berry Astronomy Program Administrative and University of Maryland Secretarial Support ________________________________________________________________________________ Creation of the IHW also required a broadening of the effort to include broad-band photometry, to be emphasized when the comet was faint, and polarimetry, to be done with the narrow-band filters in order to separate the polarization of emission bands from that of the reflected continuum. Narrow-band filters were therefore distributed to both photometrists and polarimetrists. In order to ensure homogeneity of the results, an extensive effort was made to establish a standard photometric system with a list of standard stars distributed around the sky. The efforts of several observers were enlisted and the analysis to establish the standard system was led by W. Osborn. Realizing that many potential observers were likely to have had little experience with cometary observations and also recognizing that the standard photometric system might not be in final form until late in the apparition of comet P/Halley and after the apparition of comet P/Giacobini-Zinner, it was decided that final calibrations of the narrow-band photometry would be done at the office of the Discipline Specialist at the University of Maryland. Ultimately, to ensure homogeneity, complete reduction of most data was carried out at the office of the Discipline Specialist. II. NARROW-BAND FILTERS The narrow-band filters that were distributed to both photometrists and polarimetrists came from a variety of sources. Although the manufacturers tried to maintain uniformity among the filters, they were not entirely successful. Since the transformations from measured magnitudes to fluxes depend on the actual profiles of the filters, the differences among the transmission profiles of the different filters are discussed. It should be kept in mind that the characteristics of the bandpasses of interference filters change with time, some much more than others. There are several reports of noticeable changes in some of the IHW filters since the time of distribution. All measurements reported here are based on data taken prior to distribution of the filters, that is, around 1982-83, except for the profile of the OH filter which was remeasured in 1988 and the profiles of the NH filters which were measured by the manufacturer in 1979. Because the OH and NH filters are treated differently from the remainder, the tabular data are included in the section with the writeup. For the remaining filters, the tabular data are all at the end of this section. All filters are identified by the nominal central wavelength [A], the nominal FWHM [A], and a serial number consisting of a letter indicating the manufacturer plus a sequential number. A. OH (3085A) This filter was designed to measure the 0-0 band of the A-X system of OH. Although the 1-1 band is in the wing of the filter, it does not contribute a large fraction of the total light. The formula for flux in Section IV.B gives the flux in the 0-0 band alone. These filters were all manufactured by Spectro-Film, Inc. of Winchester, Mass., and are, in a sense, a special case because the primary bandpass is centered near 3075A with a full-width-half-maximum FWHM = 80A but there is also a secondary bandpass near 3580A which is lower in transmission by more than two orders of magnitude but wider by about one order of magnitude. It thus transmits, for a flat spectrum, a flux of a few percent that of the primary bandpass. This secondary bandpass is the dominant source of light at large airmasses because the atmospheric transmission is so much greater at the wavelength of the secondary bandpass than at the wavelength of the primary bandpass. Since there is only one filter of interest for comet P/Giacobini- Zinner, the one used at Lowell Observatory, Table II presents its transmission curve. Table II. Transmission Curve of the OH Filter 3085/75 (#S2) ________________________________________________________________________________ Lambda Trans. Lambda Trans. Lambda Trans. Lambda Trans. [A] [A] [A] [A] ________________________________________________________________________________ 2920 .000020 3090 .36125 3270 .0001375 3580 .002850 2930 .0000285 3100 .33125 3280 .000110 3590 .00275 2940 .000050 3110 .24125 3290 .0000975 3600 .00255 2950 .0001075 3120 .12125 3300 .00008 3620 .002275 2960 .000225 3130 .0500 3320 .000055 3640 .002100 2970 .000485 3140 .02125 3340 .0000475 3660 .0020875 2980 .00095 3150 .010 3360 .0000375 3680 .0020 2990 .0020 3160 .00570 3380 .00003375 3700 .0018625 3000 .0045 3170 .00325 3400 .0000325 3720 .0016625 3010 .01125 3180 .002025 3420 .0000375 3740 .001375 3020 .03 3190 .001325 3440 .000050 3760 .0010375 3030 .095 3200 .000925 3460 .0000925 3780 .000750 3040 .25 3210 .00065 3480 .0001025 3800 .0004875 3050 .385 3220 .000473 3500 .000275 3820 .0002875 3054 .3950 3230 .000360 3520 .0005375 3840 .00015 3060 .38875 3240 .000285 3540 .0012125 3860 .0000575 3070 .3775 3250 .000215 3560 .0022875 3880 .000015 3080 .37375 3260 .000175 3570 .0027375 3900 .0000025 ________________________________________________________________________________ B. NH (3365A) The filters for NH were not distributed as part of the IHW effort but several older filters were available from previous programs. These filters were used at Lowell Observatory, at Cerro Tololo Inter-American Observatory, and at Perth Observatory. They were chosen to measure the delta-v = 0 sequence of the A-X system of NH. Although the entire sequence is in the bandpass, virtually all of the light is from the 0-0 band because the Franck-Condon factors are low for the other bands. The filters were also manufactured by Spectro-Film, Inc. although many years before the OH filters. Since the NH filters are not very well matched, the only way to characterize them is to present the transmission curve for each of them (Table III). Table III. Transmission Curves of the NH Filters 3365/70 ________________________________________________________ Transmission Lambda ______________________________________________ [A] Filter #S1 Filter #S2 Filter #S3 ________________________________________________________ 3200 .002 .002 .001 3225 .002 .002 .002 3250 .003 .003 .002 3275 .005 .005 .003 3300 .012 .010 .010 3325 .088 .082 .058 3350 .310 .300 .265 3375 .375 .368 .332 3400 .225 .240 .290 3425 .045 .050 .080 3450 .010 .011 .013 3475 .004 .003 .003 3500 .002 .002 .002 ________________________________________________________ C. Continuum 3650A The early filters of this type were produced by MicroCoatings, Inc. of Burlington, Mass. while the later ones were produced by Andover Corp. of Lawrence, Mass. Approximately 75 were distributed. Since the two companies used different techniques to manufacture the filters, the characteristics came out rather different. Although the filter is intended for the continuum, there are some weak ionic bands present in the wings of the filter. Preliminary calculations show that the contamination by these ions (CO+ and CO2+) is not significant. D. CN (3871A) This filter is intended to measure the delta-v = 0 sequence of the B-X system of CN. Like the 3650 filters, the early ones were made by MicroCoatings, Inc., the later ones by Andover Corp. The entire delta-v = 0 sequence is included but since the 1-1 band is weaker than the 0-0 band by a full order of magnitude, the flux is 90% due to the 0-0 band. The reduction formulae in Section IV.B give the flux in the complete delta-v = 0 sequence. E. C3 (4060A) This filter is intended to measure a portion of the A-X Swings system of C3 which extends over approximately 150A in this region. The filter was chosen to measure that portion of the emission band that is least contaminated by other features (at the short wavelengths by the strongest of the CO+ bands). The reduction formulae in Section IV.B, however, are for the flux integrated over the entire band, based on published profiles which are assumed to remain the same in all comets. These filters were also manufactured both by MicroCoatings, Inc. and by Andover Corp. F. CO+ (4260A) Since the strongest band of CO+, the 3-0 band, is inextricably in- volved with the C3 band, this filter was chosen to cover the 2-0 band of the A-X system. These filters were all made by Barr Associates, Inc., of Westford, Mass. Our results indicate a strong sensitivity to the subtraction of continuum relative to which the emission band is weak except in distant parts of the ion tail. G. Continuum 4845A This region of the continuum is noticeably contaminated by the high vibrational and rotational components of the delta-v = 0 sequence of C2 which is predominantly at longer wavelengths. Our standard reduction corrects for this contamination. The filters were manufactured by MicroCoatings, Inc. and by Andover Corp. H. C2 (5140A) This filter measures the delta-v = 0 sequence of the Swan (d-a) system of C2. The filters were manufactured both by MicroCoatings, Inc. and by Andover Corp. J. Continuum 6840A This filter also measures a relatively 'clean' region of the continuum. There is some weak emission by NH2 in this region but it does not appear to be a significant contributor. Because this band includes the Fraunhofer line B, which is due to telluric oxygen, there is a possibility that atmospheric extinction in this band might be affected by curve-of-growth effects. No allowance has been made for this in our reductions. The most obvious alternative location for a red continuum filter would involve interference from the telluric water vapor absorption and cause greater problems. These filters were all manufactured by Barr Associates, Inc. K. H2O+ (7000A) This filter was chosen to isolate the (0,6,0)-(0,0,0) band of H2O+. Because this band is very broad and the filter was designed to encompass all of it, the bandpass tends to be dominated by continuum in the head of many comets and the deduced flux is therefore sensitive to the precison of the subtraction of continuum. There is also some contamination by an emission band of NH2. The filters were all manufactured by Barr Associates, Inc. Characteristics of all the filters except those for OH and NH are given in Table IV. Each filter is identified by its peak wavelength, FWHM (following a slash), and the manufacturer. Listed are the mean and, in (), the rms scatter for the peak wavelength, the peak transmission, and the full widths at 80%, 50%, 10%, and 1% of peak transmission. Table V presents the full widths for several actual filters--the overall narrowest one (Nr.), an average (Av.), and the widest (Wd.). The numbers in () are the most extreme values found. Table VI shows the complete profile for one filter of each type. In Tables V and VI the individual filters are identified by the manufacturer (M = MicroCoatings, Inc.; A = Andover Corp.; B = Barr Asso- ciates) and its assigned number. Table IV. Average Characteristics of the IHW Narrow-Band Filters ________________________________________________________________________________ Filter Lambda Trans. Width(80%) Width(50%) Width(10%) Width(1%) [A]/[A] [A] [A] [A] [A] [A] ________________________________________________________________________________ 3650/80 Mic. 3650.1(5.5) .368(.050) 57.7(4.3) 82.5(3.4) 126(4.8) 191(6.5) And. 3644.2(4.1) .295(.029) 68.3(1.3) 88.1(1.7) 125(2.9) 180(4.0) 3871/50 Mic. 3871.6(2.7) .264(.030) 31.3(4.4) 44.2(3.9) 70(5.6) 115(8.4) And. 3870.2(2.3) .312(.031) 30.4(0.6) 42.4(1.4) 64(2.2) 92(1.2) 4060/70 Mic. 4057.9(2.0) .458(.009) 62.6(1.9) 76.7(2.0) 100(3.5) 137(5.0) And. 4054.1(1.8) .487(.020) 59.1(3.5) 70.5(2.9) 91(1.3) 117(2.3) 4260/65 Barr 4259.8(5.8) .445(.009) 62.1(1.4) 69.8(0.4) 76(0.5) 79(1.6) 4845/65 Mic. 4848.1(5.6) .721(.009) 56.9(1.9) 71.7(1.0) 100(1.6) 143(2.8) And. 4849.0(1.1) .739(.008) 52.4(1.0) 65.0(0.6) 90(0.4) 5140/90 Mic. 5140.4(5.2) .629(.010) 74.2(3.5) 85.3(2.2) 108(1.7) 142(3.3) And. 5141.3(4.5) .739(.017) 71.3(2.7) 82.6(4.2) 106(5.4) 155 6840/90 Barr 6840.3(15.) .788(.016) 79.9(4.9) 90.9(4.4) 114(4.2) 146(5.4) 7000/175 Barr 7025.9(3.6) .791(.013) 215(1.3) 228(1.2) 259(2.2) 311(2.7) ________________________________________________________________________________ Table V. Characteristics of Filters--Narrowest, Average, and Widest ____________________________________________________________________ Filter Desc. Ident. Width(80%) Width(50%) Width(10%) Width(1%) [A]/[A] [A] [A] [A] [A] ____________________________________________________________________ 3650/80 Nr. M32 54(49) 79 123(121) 184(182) Av. M 3 57 81 125 Wd. M37 67 88(89) 128(137) 201 Nr. A36 66(65) 88(86) 126(114) 169 Av. A30 68 87 124 181 Wd. A34 68(72) 90(92) 127(129) 183(184) 3871/50 Nr. M30 28(21) 41(38) 63(62) 98 Av. M41 31 44 71 118 Wd. M43 35(46) 49(50) 77(82) 125(127) Nr. A26 30(29) 42(40) 62(61) 90 Av. A17 30 42 64 92 Wd. A13 31 42 73 (94) 4060/70 Nr. M49 60(58) 72 92 130 Av. M25 63 77 101 Wd. M38 64(65) 78(80) 104 144(146) Nr. A33 53 59 89 116(111) Av. A22 59 70 91 117 Wd. A14 64 74 92(93) (120) 4260/65 Nr. B10 61 69 76(75) 78(77) Av. B 4 63 70 76 78 Wd. B25 63(64) 70 76 83 4845/65 Nr. M25 51 70(69) 99(98) (139) Av. M21 57 73 100 143 Wd. M33 59(60) 73 101(109) 148 Nr. A22 51 64 91 Av. A12 52 65 90 Wd. A17 52(54) 66 90(91) 5140/90 Nr. M14 56 80 104 (137) Av. M41 74 86 108 141 Wd. M36 79 90 113 148 Nr. A14 68 80 103 Av. A20 71 81 104 Wd. A29 77 92 118 155 6840/90 Nr. B23 68 83 110 141 Av. B21 80 92 115 148 Wd. B54 94 95 120 152 7000/175 Nr. B 3 215(211) 227 256 307 Av. B51 216 229 258 309 Wd. B15 217 229(232) 260(263) 320 ____________________________________________________________________ Table VI. Transmission Curves of Actual Filters _____________________________________________________________ Lambda Trans. Lambda Trans. Lambda Trans. Lambda Trans. [A] [A] [A] [A] _____________________________________________________________ Filter: 3650/80; M30 3522 .00152 3587 .08181 3652 .3030 3717 .0237 3527 .00167 3592 .1169 3657 .3030 3722 .0130 3532 .00200 3597 .1515 3662 .3030 3727 .0079 3537 .00222 3602 .2030 3667 .3006 3732 .00303 3542 .00242 3607 .2424 3672 .2912 3737 .00285 3547 .00258 3612 .2783 3677 .2424 3742 .00278 3552 .00303 3617 .2912 3682 .20907 3747 .00248 3557 .00576 3622 .2936 3687 .1515 3752 .00222 3562 .00788 3627 .29827 3692 .1224 3757 .00217 3567 .00939 3632 .3013 3697 .0821 3762 .00203 3572 .02275 3637 .3013 3702 .0559 3767 .00192 3577 .02908 3642 .3030 3707 .0297 3772 .00152 3582 .0303 3647 .3030 3712 .0266 Filter: 3871/50; A16 3802 .00033 3842 .03343 3882 .3316 3922 .04072 3807 .00078 3847 .08311 3887 .3343 3927 .02804 3812 .00147 3852 .1327 3892 .3289 3932 .02117 3817 .00207 3857 .1932 3897 .3049 3937 .00669 3822 .00289 3862 .2474 3902 .2675 3942 .00319 3827 .00613 3867 .2835 3907 .2163 3947 .00215 3832 .01297 3872 .3129 3912 .1488 3952 .00152 3837 .02609 3877 .3236 3917 .09772 3957 .00078 3962 .00033 Filter: 4060/70; A22 3972 .00026 4012 .1592 4052 .512 4092 .2326 3977 .00038 4017 .256 4057 .5079 4097 .1335 3982 .00051 4022 .3911 4062 .5038 4102 .0512 3987 .00187 4027 .4628 4067 .49152 4107 .02638 3992 .00359 4032 .4833 4072 .49152 4112 .00512 3997 .00512 4037 .4997 4077 .49152 4117 .00051 4002 .02638 4042 .5079 4082 .45056 4122 .00038 4007 .0512 4047 .512 4087 .3873 4127 .00026 Filter: 4260/65; B4 4200 .001 4230 .390 4260 .445 4290 .351 4205 .002 4235 .393 4265 .439 4295 .199 4210 .007 4240 .404 4270 .430 4300 .071 4215 .021 4245 .427 4275 .422 4305 .022 4220 .084 4250 .442 4280 .415 4310 .008 4225 .261 4255 .447 4285 .405 4315 .003 4320 .001 Filter: 4845/65; M21 4714 .00042 4779 .02952 4844 .6833 4909 .04197 4719 .00048 4784 .03959 4849 .6778 4914 .03557 4724 .00052 4789 .04726 4854 .6669 4919 .02459 4729 .00056 4794 .06087 4859 .6505 4924 .01342 4734 .00066 4799 .1084 4864 .6450 4929 .00664 4739 .00104 4804 .2317 4869 .6286 4934 .00374 4744 .00194 4809 .3178 4874 .5739 4939 .00282 4749 .00274 4814 .4677 4879 .4481 4944 .00200 4754 .00425 4819 .5849 4884 .3178 4949 .00131 4759 .00508 4824 .6395 4889 .2287 4454 .00100 4764 .00629 4829 .6559 4894 .1084 4459 .00076 4769 .01140 4834 .6724 4899 .06320 4464 .00066 4774 .01781 4839 .6833 4909 .05039 4969 .00044 4974 .00042 Filter: 5140/90; M5 5030 .00017 5099 .3945 5144 .6109 5189 .1660 5034 .00020 5104 .5649 5149 .6039 5194 .08551 5044 .00030 5109 .5598 5154 .6067 5204 .02393 5054 .00054 5114 .5408 5159 .6166 5214 .00724 5064 .00137 5119 .5546 5164 .6295 5224 .00254 5074 .00521 5124 .5875 5169 .6194 5234 .00122 5084 .02786 5129 .6166 5174 .5623 5244 .00065 5089 .07112 5134 .6310 5179 .4446 5254 .00041 5094 .1862 5139 .6237 5184 .2858 5264 .00027 5271 .00021 Filter: 6840/90; B21 6750 .00000 6795 .43956 6840 .81500 6885 .45000 6755 .00400 6800 .65919 6845 .81100 6890 .25000 6760 .00600 6805 .77105 6850 .80700 6895 .11985 6765 .00800 6810 .79502 6855 .79901 6900 .05990 6770 .02000 6815 .79901 6860 .79303 6905 .03196 6775 .02796 6820 .79901 6865 .79102 6910 .01598 6780 .05992 6825 .80700 6870 .79000 6915 .08000 6785 .08000 6830 .81100 6875 .77000 6920 .00400 6790 .23970 6835 .81200 6880 .66000 6925 .00023 6930 .00000 Filter: 7000/175; B7 6850 .003 6940 .746 7030 .826 7120 .791 6855 .004 6945 .748 7035 .825 7125 .752 6860 .005 6950 .756 7040 .825 7130 .610 6865 .007 6955 .770 7045 .826 7135 .418 6870 .010 6960 .783 7050 .827 7140 .249 6875 .015 6965 .794 7055 .825 7145 .142 6880 .022 6970 .801 7060 .823 7150 .080 6885 .036 6975 .806 7065 .820 7155 .048 6890 .060 6980 .808 7070 .809 7160 .029 6895 .102 6985 .809 7075 .793 7165 .018 6900 .177 6990 .812 7080 .773 7170 .011 6905 .300 6995 .814 7085 .748 7175 .008 6910 .475 7000 .816 7090 .726 7180 .006 6915 .475 7005 .819 7095 .711 7185 .004 6920 .753 7010 .822 7100 .706 7190 .003 6925 .780 7015 .823 7105 .715 7195 .002 6930 .769 7020 .824 7110 .735 7200 .001 6935 .754 7025 .825 7115 .772 _____________________________________________________________ III. STANDARD STARS A. Standards for Narrow-Band Photometry An extensive set of standard stars was defined using the narrow-band filters distributed by the IHW. Primary standard stars were chosen to be of two types: solar analogs and stars of spectral types O9-B3. The early-type stars were chosen to have the most line-free spectra and to be distributed along the celestial equator while the solar analogs were chosen to be those most nearly like the Sun in the work of Hardorp (1978, 1980a,b, 1982). The solar analogs were used to determine the continuum underlying the emission bands of the comet and are marked in the table below. Secondary standards were chosen in other parts of the sky. Observations were obtained at several sites using different sets of the standard filters and different photometers. The observations were synthesized by W. Osborn to establish the standard magnitudes. The zero- point of the system was arbitrarily set to be m = 5.88 for all filters for the star 53 Psc = HD 3379 (V = 5.88). Empirically there appears to be nothing more than a zero point shift between instrumental magnitudes and the standard magnitudes in nearly all cases. In a few cases, that is, for certain sets of filters, the zero point shift of the CN filter is slightly different for G-stars and for B-stars and presumably, therefore, for comets. A complete paper on the standards is in preparation at the time of this writing and a more complete discussion of the standards will appear among the appendices to the archive of data on comet P/Halley. Table VII. The Set of Standard Stars for Narrow-Band Photometry __________________________________________________________________________________________________________ Monochromatic Magnitude at Wavelength [A] HD# R.A.(1950)Decl -------------------------------------------------------------------- Spectrum 3085 3365 3650 3871 4060 4260 4845 5140 6840 7000 __________________________________________________________________________________________________________ 3379 00 34 10.8 +14 57 24 5.880 5.880 5.880 5.880 5.880 5.880 5.880 5.880 5.880 5.880 B2.5IV * 10126 01 36 45.6 27 51 22 10.497 9.768 9.304 9.727 8.978 8.863 8.011 7.999 7.11 7.09 G8V 13974 02 13 59.6 33 59 48 7.069 6.494 6.141 6.252 5.902 5.811 5.130 5.096 4.290 4.25 G0V 16397 02 35 30.9 30 36 24 9.532 8.943 8.559 8.683 8.340 8.265 7.596 7.546 6.81 6.87 G1V 16908 02 40 30.7 27 29 44 4.735 4.742 4.725 4.677 4.676 4.677 4.668 4.665 4.626 4.641 B3V 18803 02 59 27.7 26 24 56 9.349 8.600 8.149 8.565 7.826 7.704 6.898 6.864 6.033 6.005 G8V 22951 03 39 12.0 33 48 22 4.925 4.932 4.893 5.107 5.161 5.146 5.017 5.023 4.862 4.892 B0.5V 23464 03 43 15.2 22 58 28 11.08 10.46 10.011 10.196 9.723 9.598 8.960 8.892 8.11 G0V 24760 03 54 29.4 39 52 03 2.433 2.529 2.549 2.807 2.933 2.948 2.885 2.952 2.885 2.956 B0.5V 25680 04 02 22.4 21 52 32 8.289 7.665 7.277 7.484 6.987 6.868 6.163 6.108 5.340 5.326 G5V 26736 04 11 32.2 23 27 02 10.581 9.896 9.472 9.732 9.178 9.055 8.318 8.269 7.433 7.360 G3V 26912 04 12 49.0 08 46 07 4.669 4.593 4.539 4.411 4.404 4.399 4.329 4.317 4.202 4.202 B3IV * 28099 04 23 47.7 16 38 07 10.631 9.958 9.547 9.823 9.227 9.097 8.364 8.312 7.51 7.48 G6V + 29461 04 36 07.6 14 00 29 10.454 9.839 9.410 9.675 9.097 8.973 8.243 8.196 7.370 7.324 G5V + 30246 04 43 38.9 15 22 59 10.861 10.170 9.767 10.053 9.456 9.340 8.585 8.539 7.68 G5V + 30455 04 45 46.3 18 37 40 9.16 8.69 8.297 8.464 8.004 7.921 7.218 7.160 6.36 6.32 G2V 31966 04 57 43.5 14 18 36 8.66 8.245 8.476 7.895 7.781 7.038 6.979 6.15 6.10 G2IV-V 36351 05 28 37.0 03 15 21 5.187 5.229 5.248 5.383 5.426 5.439 5.419 5.444 5.436 5.452 B1.5V 41753 06 04 42.9 14 46 34 4.43 4.41 4.408 4.382 4.393 4.405 4.403 4.410 4.404 4.426 B3V 44594 06 18 47.1 -48 42 50 9.110 8.496 8.051 8.319 7.726 7.613 6.889 6.832 6.011 5.977 G2V + 47032 06 34 07.4 04 44 14 9.776 9.57 9.396 9.577 9.594 9.516 9.116 8.984 8.303 8.260 B2 52266 06 57 53.9 -05 45 21 7.053 7.075 7.037 7.327 7.415 7.404 7.240 7.256 7.040 7.048 O9V * 74280 08 40 36.7 03 34 46 4.196 4.206 4.198 4.240 4.265 4.283 4.275 4.293 4.296 4.324 B4V * 76151 08 51 50.1 -05 14 39 8.525 7.898 7.462 7.810 7.152 7.044 6.291 6.238 5.404 5.371 G3V 84971 09 46 12.4 -02 28 50 8.579 8.597 8.583 8.620 8.665 8.679 8.629 8.660 8.612 8.631 B2.5V 88725 10 11 32.1 03 24 19 9.970 9.413 9.003 9.145 8.791 8.720 8.020 7.963 7.152 7.117 G1V 89688 10 18 27.1 02 32 31 6.838 6.802 6.756 6.734 6.766 6.761 6.671 6.682 6.584 6.596 B2.5IV * 96700 11 05 31.5 -29 54 07 8.815 8.242 7.845 7.995 7.569 7.480 6.803 6.733 5.949 5.917 G2V 97991 11 13 38.6 -03 11 57 6.943 7.038 7.055 7.283 7.348 7.374 7.355 7.401 7.421 7.446 B1V 99171 11 21 58.1 -42 23 39 5.924 5.989 5.975 6.087 6.118 6.132 6.115 6.141 6.129 6.152 B2V 104337 11 58 17.5 -19 22 50 4.955 5.019 5.028 5.193 5.256 5.277 5.240 5.283 5.283 5.312 B1.5V 105590 12 06 53.2 -11 34 36 9.365 8.727 8.296 8.593 8.000 7.890 7.141 7.089 6.248 6.216 G2V + 112185 12 51 50.1 +56 13 51 3.23 3.02 2.84 2.10 1.98 1.93 2.00 1.89 1.59 1.65 B2 120086 13 44 44.2 -02 11 40 7.653 7.697 7.695 7.813 7.855 7.862 7.845 7.873 7.867 7.888 B3III * 120315 13 45 34.3 49 33 44 1.89 1.90 1.91 1.90 1.91 1.91 1.94 1.94 1.86 1.89 B3V * 121849 13 55 42.9 -33 45 15 10.743 10.024 9.614 9.874 9.339 9.256 8.466 8.421 7.542 7.506 G5V 122980 14 02 59.0 -40 56 28 4.159 4.161 4.188 4.301 4.325 4.334 4.342 4.358 4.365 4.386 B2V 124580 14 12 27.6 -44 46 00 8.593 8.014 7.644 7.769 7.390 7.285 6.624 6.550 5.773 5.745 G1V 133955 15 05 27.9 -45 05 20 4.054 4.017 4.035 4.062 4.060 4.066 4.075 4.065 4.049 4.054 B3V 136352 15 18 25.2 -48 08 06 8.062 7.425 7.012 7.221 6.754 6.673 5.944 5.896 5.066 5.033 G2V 137432 15 24 05.5 -36 35 37 5.600 5.570 5.561 5.504 5.472 5.475 5.492 5.455 5.416 5.437 B4V 148045 16 24 27.7 -56 34 03 10.83 10.07 9.86 9.61 9.48 9.06 8.94 8.32 8.31 G0V 149363 16 31 47.9 -06 01 59 7.770 7.752 7.706 7.938 8.027 8.007 7.818 7.823 7.590 7.600 B0.5III* 149438 16 32 45.9 -28 06 51 2.26 2.281 2.340 2.656 2.767 2.801 2.780 2.820 2.84 2.89 B0V 164852 18 00 14.7 20 49 57 5.443 5.398 5.372 5.337 5.323 5.317 5.292 5.269 5.186 5.208 B3V * 165185 18 03 00.9 -36 01 32 8.207 7.648 7.245 7.381 6.988 6.874 6.212 6.139 5.374 5.352 G5V 166197 18 07 36.8 -33 48 40 5.903 5.956 5.932 6.104 6.184 6.190 6.113 6.154 6.081 6.106 B1V 175191 18 52 09.9 -26 21 38 1.955 1.95 1.955 2.02 2.045 2.065 2.09 2.09 1.92 1.95 B2.5V 186427 19 40 32.0 50 24 03 8.779 8.093 7.671 7.946 7.350 7.240 6.492 6.451 5.616 5.635 G5V + 189340 19 57 04.3 -10 05 25 8.094 7.518 7.170 7.249 6.882 6.768 6.138 6.075 5.315 5.296 G0V 191263 20 06 15.1 10 34 44 6.430 6.410 6.390 6.366 6.365 6.364 6.347 6.346 6.302 6.328 B3IV * 191639 20 08 27.5 -08 59 30 6.099 6.159 6.153 6.394 6.486 6.495 6.423 6.475 6.432 6.463 B1V 191854 20 08 33.7 43 47 43 9.982 9.274 8.864 9.134 8.539 8.433 7.671 7.641 6.813 6.817 G1 + 193901 20 20 38.8 -21 31 05 10.573 10.028 9.723 9.775 9.585 9.494 8.903 8.827 8.072 8.049 G3V 198188 20 46 21.9 -20 48 51 10.428 9.819 9.438 9.609 9.153 9.053 8.394 8.325 7.559 7.543 G0V 214680 22 37 00.7 38 47 22 4.268 4.349 4.381 4.716 4.834 4.858 4.811 4.880 4.898 4.921 B2 218687 23 07 27.5 14 09 22 8.793 8.211 7.846 7.984 7.586 7.475 6.821 6.760 6.003 5.976 G0V 219188 23 11 28.0 04 43 29 6.675 6.723 6.727 6.992 7.100 7.102 7.001 7.062 6.992 7.023 B0.5III* __________________________________________________________________________________________________________ * Primary flux standards (equatorial). + Primary solar analogs. Table VIII. Solar Analog Colors ______________________________________________________________________ Monochromatic Magnitude at Wavelength [A] Relative to 4845 A HD# ------------------------------------------------------------- 3085 3365 3650 3871 4060 4260 5140 6840 7000 ______________________________________________________________________ 28099 2.267 1.594 1.183 1.459 .863 .733 -.052 -.854 -.884 29461 2.211 1.596 1.167 1.432 .854 .730 -.047 -.873 -.919 30246 2.276 1.585 1.182 1.468 .871 .755 -.046 -.905 44594 2.221 1.607 1.162 1.430 .837 .724 -.057 -.878 -.912 105590 2.224 1.586 1.155 1.452 .859 .749 -.052 -.893 -.925 186427 2.287 1.601 1.179 1.454 .858 .748 -.041 -.876 -.857 191854 2.311 1.603 1.193 1.463 .868 .762 -.030 -.858 -.854 Mean 2.257 1.596 1.174 1.451 .859 .743 -.046 -.872 -.894 Sigma .038 .008 .013 .015 .011 .014 .009 .014 .029 ________________________________________________________________________ B. Standards for Polarimetry Both highly polarized stars (POL-STD in the FITS HISTORY keyword) and unpolarized stars (UNPOL-STD in the FITS HISTORY keyword) were used to calibrate the polarimetric measurements. The standard values were taken from the literature (Hsu and Breger, 1982). POL-STD : HD 187929, HD 7927 UNPOL-STD : HD 188512 IV. REDUCTION OF NARROW-BAND PHOTOMETRY In this section are described the methods and formulae used at the University of Maryland to reduce the narrow-band photometric data. Most data were reduced at Maryland, using these methods. Significant deviations from these procedures are noted in the archive as comments for the relevant observations. A. Atmospheric Effects and Reduction to Standard Magnitudes The most basic data with which we could begin reductions consisted of Universal Times and counting rates on the various objects and on the sky. In the case of measurements with direct-current systems rather than pulse-counting systems, the most basic data would consist of readings from the d.c. amplifier and Universal Times. Some observers submitted data in various stages of reduction beyond these most basic data and in general we do not know the details of the reductions applied by such observers. We will describe here the complete reduction from the most basic data as we carried it out. Instrumental magnitudes were derived by first correcting all counting-rates for the dead-time of the amplifier using the formula n = n(obs)/[1.0 - n(obs)*tau] where tau is the dead-time of the amplifier and n and n(obs) are the 'true' and observed counting rates, respectively. These counting rates were converted to instrumental magnitudes by choosing an appropriate counting rate n(sky) for the sky brightness (by interpolation where appropriate and possible) and using m = 20.00 - 2.5*log[n(object) - n(sky)]. Air masses were calculated for each observation in the following manner beginning with the coordinates of the observatory and the coordinates (current epoch) of the object. True zenith distance, Z: sec Z = 1/[sin(lat)*sin(dec) + cos(lat)*cos(dec)*cos(local hour angle)]. Apparent zenith distance, Zapp: Zapp = Z - [60.4*tan(Z) - .06688*tan(Z)**3] where the term in [ ] is in arcsec. Airmass, X, is then: X = sec(Zapp) - .0018167*[sec(Zapp)-1] - .002875*[sec(Zapp)-1]**2 - .0008083*[sec(Zapp)-1]**3. Although atmospheric attenuation is normally linear with airmass as defined above, this is not the case for observations with the OH filters because the monochromatic attenuation varies drastically across the bandpass. In order to simplify the reductions, particularly when only limited data were available, the non-linearity of the atmospheric attenuation was modelled by defining an effective airmass, Xeff, such that attenuation would be linear in this variable. Unfortunately, the non-linearity varies from one site to another and even with time at a single site due to differences in the amount of atmosphere above the site (changing the Rayleigh component), in the amount of aerosol at the site, and in the amount of ozone above the site. Furthermore, the non-linearity depends on the color of the source being observed. Fortunately we are interested only in sources of three colors - B-stars, solar analogs, and cometary emission bands. We can therefore define effective airmasses separately for each of the three cases. The details of the atmospheric modelling will be described elsewhere but our general approach, based on that of Hayes and Latham (1975), is to use a three-component model for the atmosphere (Rayleigh, aerosol, ozone) to calculate the monochromatic extinction. The altitude of the observatory defines the Rayleigh component whereas the aerosol and ozone components are allowed to vary within ranges expected for a given site. The monochromatic extinction for various airmasses is then multiplied by the spectral distribution of a B-star, a G-star, and a cometary emission band and the resultant flux is multiplied by the transmission curve of the filter yielding magnitudes as a function of airmass. The resultant theoretically calculated magnitudes are compared with whatever observations are available, usually a large set of observations of the B-stars observed over a wide range of airmasses during a single observing run. The two free parameters (ozone column density and aerosol abundance) are varied until the observed data are reproduced by the model. (Usually only the ozone abundance needs to be varied significantly and it turns out that in cases studied so far this remains within the ranges expected for a given latitude and season.) We then use the calculated variation of magnitude with airmass to define the effective airmass, Xeff, such that the extinction is linear. It appears adequate to use a quadratic polynomial: Xeff = X + a*X**2 where a is in principle different for every site (conceivably every observing run due to seasonal effects in ozone abundance) and different for B-stars, G-stars, and comets. For comet P/Giacobini-Zinner, the only archived OH data were obtained at Lowell Observatory and for these data the values of a are given by: a(B-star) = .04551 a(G-star) = .07961 a(comet) = .009286 Since in practice one determines extinction only from B-stars or only from B- and G-stars, it is also necessary to know the ratio of extinction coefficents for the three classes of objects once they have all been linearized by the above formulae. This ratio is also derived from the model. For the model which represented the observed curvature in the data from Lowell Observatory, the ratio of extinction coefficients k (in units of Xeff) was given by k(comet) = .924*k(B-star). Given a set of observations of standard stars, extinction coefficients were determined in a variety of ways. In most cases we determined atmospheric extinction for each night by two methods, conventional fitting by least squares of magnitude vs. airmass for individual stars and also a global least squares solution using all standards in which we solved simultaneously for the extinction coefficient and the zero-point shift from instrumental magnitude to standard magnitudes. The result of the global solution was normally used unless the solutions for individual stars suggested hemispheric asymmetries and/or temporal variations during the night. In these cases we then solved separately for different hemispheres and/or parts of the night. In some cases we also averaged several nights together to define average extinction coefficients either when there were too few data on a particular night to determine extinction or when the scatter from night to night was no larger than expected from the errors in the results of the individual nights. Different types of extinction fitting are noted in the remarks column of the archive. When global solutions for extinction were not used, magnitudes were transformed to the standard system by a least squares solution for the zero-point shift with no color terms. It was at this point that a certain amount of discretion was exercised in our operation. If individual observations or even all the observations of a single object seemed discrepant, and if we were able to identify a physically plausible mechanism for producing the discrepancy, we often discarded some observations. In a few cases, we even discarded the data from entire nights at this point. We should point out that in some cases the observers had already advised us that the data were of poor quality but we had requested that they submit everything in the hope that we could salvage some marginal data if it turned out to be critical for filling in a significant gap in the light curve. The subjective comments of the observers were of great help in understanding the effects of atmospheric extinction. B. Conversion to Fluxes The following procedures were used to derive fluxes in the continuum bandpasses. We first applied a correction due to the fact that the filter at 4845A, nominally a continuum filter, also includes a weak tail of emission from the delta-v = 0 sequence of the Swan system of C2 which is measured by the filter at 5140A. This correction was done in magnitude units using mcont(4845) = m(4845) + 0.012*[m(4845)-m(5140)]. The coefficient 0.012 was derived on the basis of theoretical spectra of the Swan bands from A'Hearn (1978). Actual spectra of comet P/Halley from Lowell Observatory suggest that the coefficient should be somewhat larger than this, perhaps as large as 0.03. In any case, the correction does not change the continuum flux drastically. The conversion from magnitudes in the standard system to fluxes in the continuum is straightforward. To generalize for future use, we arbitrarily define mcont(6840) = m(6840) and mcont(3650) = m(3650). We also define Fcont(lambda) = 10**[-0.4 * mcont(lambda)] The flux per unit wavelength [erg/cm**2/s/A] is then given by: Flam(3650) = (8.22 +/- .13)*10**(-9) * Fcont(3650) Flam(4845) = (5.10 +/- .30)*10**(-9) * Fcont(4845) Flam(6840) = (1.65 +/- .02)*10**(-9) * Fcont(6840). The 'errors' given with the coefficients are a measure of the variation in the flux transformation from one filter to another and, for a given filter, with temperature over the range -20C to +20C. Derivation of fluxes in emission bands is somewhat more complicated. The first step is to remove the continuum which underlies the emission band and which is also detected through the filters. This is done using the colors of the solar analogs (Table VIII) and measurements of the comet in any two continuum bandpasses - (3650,4845), (3650,6840), or (4845,6840). For each pair of filters, we interpolate (or extrapolate) the magnitudes of the solar analogs to the wavelength of an emission-band filter and determine the difference between the measured magnitude and the interpolated magnitude, C. For the comet, we then interpolate the magnitudes in the same two continuum filters and add C to estimate the continuum contribution to the measured magnitude. This procedure is accurate if the cometary continuum in magnitudes is redder (or bluer) than the sun linearly with wavelength. If there is curvature or structure in the continuum reflectivity of the cometary grains, then this procedure is not adequate. The general form of the equation is: mcont(i) = A*mcont(cont1) + (1-A)*mcont(cont2) + B(i) where i refers to the ith emission band designated by its wavelength, A and (1-A) are the coefficients for the interpolation which depend only on the wavelengths of the 3 filters, and B is as described above. In Table IX we give the coefficents for the continuum correction for each emission band filter and for each of the three possible pairs of continuum bandpasses. We also give an error in B which is a measure of the scatter from one solar analog to another. Table IX. Coefficients for Continuum Subtraction ________________________________________________ cont1/cont2 Filter ------------------------------------ 3650/4845 4845/6840 3650/6840 ________________________________________________ OH A 1.4728 1.8822 1.1771 (3085) B .528 1.488 .721 sigma(B) .040 .037 .038 NH A 1.2385 1.7419 1.0893 (3365) B .142 .949 .239 sigma(B) .018 .013 .015 CN A .8151 1.4882 .9307 (3871) B .494 1.025 .419 sigma(B) .018 .015 .018 C3 A .6569 1.3935 .8715 (4060) B .088 .516 -.052 sigma(B) .014 .011 .015 CO+ A .4895 1.2932 .8088 (4260) B .168 .487 -.040 sigma(B) .015 .014 .016 C2 A -.2469 .8521 .5329 (5140) B .244 .083 -.264 sigma(B) .010 .008 .012 H2O+ A -1.8033 -.0802 -.0502 (7000) B 1.223 .048 .083 sigma(B) .037 .030 .030 ________________________________________________ In reducing the data we often had a choice of which continuum bandpasses to use for the continuum subtraction. We always chose inter- polation over extrapolation and the shorter of the two possible baselines. To define the fluxes in the emission bands, we first define: F(i) = 10**[-0.4*m(i)] Fcont(i) = 10**[-0.4*mcont(i)] where we will denote the individual emission bands, i, by their wavelengths [A]. The true fluxes in the emission bands [erg/cm**2/s] are then given by: F(OH) = (Y1 - 0.0015*T)*10**(-6) * [F(3085) - Fcont(3085)] F(NH) = (Y2)*10**(-7) * [F(3365) - Fcont(3365)] F(CN) = (Y3 - .0021*T)*10**(-6) * [F(3870) - Fcont(3870)] F(C3) = (1.381 + .003*T)*10**(-6) * [F(4060) - Fcont(4060)] F(CO+) = (5.90 - .005*T)*10**(-7) * [F(4260) - Fcont(4260)] F(C2) = 6.81*10**(-7) * [F(5140) - Fcont(5140)] F(H2O+) = 3.58*10**(-7) * [F(7000) - Fcont(7000)] where T is the temperature [deg C] of the filter. The coefficients Y1, Y2, and Y3 must be tabulated. Y2 varies from one filter to another because the filters for NH (which are not widely distributed) are much older than the filters distributed by the IHW and they are not nearly as well matched to each other. For filter #S1, Y2 = 8.079 + .0080*T; for filter #S2, Y2 = 8.240 + .0095*T; for filter #S3, Y2 = 9.040 + .0150*T. The coefficients Y1 and Y3, on the other hand, vary with the comet's heliocentric radial velocity Vr because of the very large Swings effect on the bands of OH and CN. These coefficients are tabulated in Table X. Table X. Transformation Coefficients Y1 for OH and Y2 for CN ____________________________________________________________________________ Vr Y1 Y3 Vr Y1 Y3 Vr Y1 Y3 Vr Y1 Y3 [km/s] [km/s] [km/s] [km/s] ____________________________________________________________________________ -60 1.080 .5277 -30 1.099 .5188 1 .5230 31 .5267 -59 .5273 -29 .5214 2 1.189 .5238 32 1.100 .5270 -58 1.086 .5276 -28 1.112 .5247 3 .5245 33 .5272 -57 .5284 -27 .5272 4 1.161 .5251 34 1.117 .5271 -56 1.093 .5304 -26 1.128 .5287 5 .5257 35 .5268 -55 .5329 -25 .5289 6 1.147 .5263 36 1.136 .5263 -54 1.101 .5358 -24 1.132 .5288 7 .5267 37 .5258 -53 .5378 -23 .5286 8 1.151 .5274 38 1.134 .5255 -52 1.106 .5380 -22 1.119 .5280 9 .5282 39 .5254 -51 .5362 -21 .5268 10 1.140 .5289 40 1.118 .5258 -50 1.111 .5333 -20 1.105 .5248 11 .5291 41 .5261 -49 .5306 -19 .5229 12 1.113 .5288 42 1.094 .5263 -48 1.128 .5285 -18 1.112 .5214 13 .5285 43 .5265 -47 .5273 -17 .5210 14 1.092 .5289 44 1.069 .5267 -46 1.156 .5269 -16 1.121 .5214 15 .5214 45 .5269 -45 .5270 -15 .5223 16 1.087 .5290 46 1.057 .5274 -44 1.170 .5277 -14 1.108 .5234 17 .5275 47 .5277 -43 .5287 -13 .5244 18 1.095 .5275 48 1.052 .5275 -42 1.146 .5300 -12 1.111 .5261 19 .5290 49 .5277 -41 .5309 -11 .5292 20 1.090 .5307 50 1.050 .5286 -40 1.126 .5307 -10 1.154 .5336 21 .5312 51 .5304 -39 .5299 - 9 .5372 22 1.074 .5309 52 1.052 .5320 -38 1.120 .5287 - 8 1.235 .5395 23 .5307 53 .5327 -37 .5275 - 7 .5402 24 1.059 .5309 54 1.057 .5323 -36 1.108 .5263 - 6 1.236 .5394 25 .5310 55 .5312 -35 .5250 - 5 .5371 26 1.054 .5305 56 1.061 .5296 -34 1.089 .5232 - 4 1.215 .5332 27 .5292 57 .5282 -33 .5208 - 3 .5290 28 1.061 .5277 58 1.064 .5269 -32 1.088 .5186 - 2 1.202 .5256 29 .5267 59 .5256 -31 .5179 - 1 .5236 30 1.078 .5266 60 1.067 .5243 0 1.208 .5228 ________________________________________________________________________________ C. Errors Errors were not always treated consistently. For the polarimetry we simply used the errors provided by the observers, who had been asked to supply the standard deviation of the final answer, both for the percent polarization and for the position angle. For the narrow-band photometry, we normally calculated the errors ourselves by propagating the errors through each step of the reduction. In some cases, however, we did not know the uncertainties, e.g., in the raw count rates, and we had to guess these errors. Wherever possible, we checked the scatter among different measurements to ensure that this was consistent with the expected error in an individual measurement. If they were not consistent, we always chose the larger error. This typically occurred when we derived the zero-point shift to the standard magnitude system. The scatter in zero-point shift from one standard star to another was often greater than one would expect from the uncertainties in the raw counting rates and in the extinction determinations. The resultant errors, when propagated through to the fluxes, represent only the photometric uncertainty. They do not include uncertainties in the transformation equations given above nor do they include uncertainties due to the scatter in characteristics among the different filters. We do know that we have neglected one significant source of error. As noted above, our algorithm for removing the continuum from the measurements of emission bands will only work if the reddening (in magnitudes) is linear with wavelength. Empirically we have found that frequently the flux of CO+ turns out to be negative. We have looked into the contamination of the continuum bandpasses by emission bands and have concluded that this is not the source of the problem. We suspect that the real problem is due to non-linearity in the reddening of the solar continuum by the cometary grains but we have no way of adequately dealing with this. The effect is most pronouced for CO+ because the band is very weak compared to the continuum near the nucleus but the problem is presumably present, to a lesser degree, for all emission bands. Other than the uncertainty due to the varying reflectivity of cometary grains, we believe that the photometric uncertainty is the largest uncertainty in the results presented here and that the quoted errors are reasonably realistic. We note that although the CO+ feature is frequently negative, it is virtually never more than 3-sigma negative. In the data tables, our general policy has been to quote 1-sigma errors. If the result is less than 3-sigma, we have usually quoted a 3-sigma upper limit but in a few cases we have included results between 2- and 3-sigma together with the errors. V. CONTENT OF THE ARCHIVE A. The Data In order to provide an overview of the archive content, Table XI offers a chronological summary of the data. Listed are the calendar date, the number of days from perihelion, t-T, the heliocentric distance, r, the number, N, and type of observations, and the names of the observer(s) and observatory. The list of the observers and their affiliations is presented in Table XII. Table XI. Chronological Listing of the Data ____________________________________________________________________________ Date UT t-T r N Type Observer(s) Observatory 1985 [days] [AU] ____________________________________________________________________________ June 15 -82 1.51 21 Fluxes Millis et al. Lowell 16 -81 1.50 21 Fluxes Millis et al. Lowell July 21 -46 1.21 40 Magnitudes Leibowitz, Brosch Wise 22 -45 1.21 104 Magnitudes Leibowitz, Brosch Wise 23 -44 1.20 152 Magnitudes Leibowitz, Brosch Wise 24 -43 1.19 152 Magnitudes Leibowitz, Brosch Wise 25 -42 1.19 32 Magnitudes Leibowitz, Brosch Wise Aug. 11 -25 1.09 44 Magnitudes Leibowitz, Brosch Wise 16 Fluxes Millis et al. Lowell 12 -24 1.08 48 Magnitudes Leibowitz, Brosch Wise 22 Fluxes Millis et al. Lowell 13 -23 1.08 8 Fluxes Millis et al. Lowell 20 -16 1.05 8 Fluxes Millis et al. Lowell 22 -14 1.05 12 Polarimetry Vrba Naval 23 -13 1.05 7 Polarimetry Vrba Naval 24 -12 1.04 8 Polarimetry Vrba Naval 81 Fluxes Andrews, Williams LaPalma 25 -11 1.04 145 Fluxes Andrews, Williams LaPalma 26 -10 1.04 108 Fluxes Andrews, Williams LaPalma Sept. 9 4 1.03 31 Fluxes Millis et al. Lowell 12 7 1.03 24 Fluxes Millis et al. Lowell 8 Fluxes Wisniewski Mt. Lemon 13 8 1.03 7 Fluxes Millis et al. Lowell 14 9 1.04 6 Polarimetry Vrba Naval 16 11 1.04 8 Fluxes Millis et al. Lowell 17 12 1.04 8 Fluxes Millis et al. Lowell 133 Fluxes Sterken, Manfroid Wise 18 13 1.04 42 Fluxes Sterken, Manfroid Wise 19 14 1.05 30 Fluxes Wolf, Vanysek Ondrejov 28 Fluxes Moreno CTIO 20 15 1.05 42 Fluxes Moreno CTIO 21 16 1.05 5 Polarimetry Vrba Naval 22 17 1.06 6 Polarimetry Vrba Naval 23 18 1.06 5 Polarimetry Vrba Naval 24 19 1.06 21 Fluxes Sterken, Manfroid Wise Oct. 13 38 1.16 8 Fluxes Millis et al. Lowell 15 40 1.17 10 Fluxes Millis et al. Lowell Nov. 7 63 1.34 8 Fluxes Millis et al. Lowell 20 76 1.45 8 Fluxes Millis et al. Lowell ____________________________________________________________________________ Total interval, 159 days; total number of observations, 1467. The data of Leibowitz and Brosch, although taken with the standard narrow-band filters, are archived here as magnitudes rather than as fluxes. These data were taken for the purpose of studying temporal variations and could not be absolutely calibrated. Since they provide a large database for searching for short-term periodicities, they are included here as magnitudes. They are on an entirely arbitrary system and should only be used for studying variability. Table XII. List of Observers and Their Affiliations ________________________________________________________________________________ Observers Affiliation Observer Affiliation ________________________________________________________________________________ M.F. A'Hearn University of Maryland, W. Pfau Friedrich-Schiller- U.S.A. Universitat, GDR P.J. Andrews Royal Greenwich Obser- D. Schleicher Lowell Observatory, vatory, U.K. U.S.A. P.V. Birch Perth Observatory, C. Sterken Vrije Universiteit, Australia Brussel, Belgium N. Brosch Wise Observatory, Israel D. Thompson Lowell Observatory, U. Carsenty University of Maryland, U.S.A. U.S.A. V. Vanysek Charles University, A. Dollfus Observatoire de Paris, Czechoslovakia France F.J. Vrba U.S. Naval Observa- M.A. Feierberg University of Maryland, tory, U.S.A. U.S.A. E. Wenderoth Universidad de Chile, E.M. Leibowitz Tel-Aviv University, Chile Israel I.P. Williams Queen Mary College, J. Manfroid Universite de Liege, U.K. Belgium W. Wisniewski University of Arizo- R.L. Millis Lowell Observatory, U.S.A. na, U.S.A. H. Moreno Universidad de Chile, M. Wolf Charles University, Chile Czechoslovakia ________________________________________________________________________________ B. The FITS Files (Digital Archive) The data from the Photometry and Polarimetry Network are stored using the Tables Extension of FITS ('EXTEND = T'). Some of the important parameters of the data are given in the standard FITS header while the remainder are given in the tables. Regardless of the type of data, the information in the FITS header is the same. The logically grouped content of the various keywords in the header is given in Table XIII. Note that some values, particularly 'TIME-OBS', have been truncated to the number of digits meaningful for all entries in the file since the times of each individual observation are given in Table XIII. Table XIII. FITS Header Keywords ________________________________________________________________________________ Item FITS Keyword Format Value/Explanation ________________________________________________________________________________ Comet Name OBJECT string 'P/GIACOBINI-ZINNER' for all files in this archive. File Number FILE-NUM I6 '54$xxx' 5 ==> Photometry/Polarimetry Network 4 ==> P/Giacobini-Zinner $=1 ==> Broadband $=2 ==> Narrowband $=0 ==> Polarimetry xxx = running number, not in chronological order Date DATE-OBS dd/mm/yy Date of the observations UT Time TIME-OBS F6.5 Decimal fraction of the day at the midpoint of the observations in the table Our Network DISCIPLN string 'PHOTOMETRY' for this Network Observatory OBSVTORY string Name of observatory Longitude LONG-OBS ddd/mm/ss Positive, eastward from Greenwich Latitude LAT--OBS sdd/mm/ss s='+' or '-' for North or South Elevation ELEV-OBS I4 [m] System SYSTEM I8 '5oooxxyy' ooo=IAU observatory code xx =serial number for the telescope relative to others in the same observatory yy=01 ==> photometer yy=02 ==> CCD yy=05 ==> polarimeter Telescope TELESCOP string A unique identification of the telescope by name or size Type of data DAT-TYPE string 'POLARIMETRY', 'BROADBAND', or 'NARROWBAND'. Note that in Table XI 'Fluxes' refers to 'NARROWBAND' and 'Magnitudes' refers to 'BROADBAND' Observer(s) OBSERVER string Names of observers Submitter SUBMITTR string Person who submitted data to the DS. A blank usually means data were taken from the literature. Comments COMMENT string All comments are character strings (line = 80 characters) following the keywords 'COMMENT' and 'HISTORY' and in some cases the following secondary keywords: 'LIT.' => reference from literature 'NOTE' => footnote to table 'NOTExx' => footnote to line xx HISTORY string 'STDSTARS' => list of standard stars used in the reduction. In case of polarimetry standard stars POL-STD refers to highly polarized stars, and UNPOL-STD to unpolarized stars. ________________________________________________________________________________ The FITS tables can take any of three different formats depending on the type of data in the table. The types of table are known by the following values for the FITS 'DAT-TYPE' keyword: 'BROADBAND', 'NARROWBAND', and 'POLARIMETRY'. Note that the value 'BROADBAND' is actually used to indicate results given in magnitudes rather than fluxes. It is independent of the actual bandwidth of the filters used. The first few columns in the tables are identical for all types of data and are listed in Table XIV. The additional entries for DAT-TYPE = BROADBAND are in Table XV, for DAT-TYPE = NARROWBAND in Table XVI, and for DAT-TYPE = POLARIMETRY in Table XVII. The format of the printed archive and the index table are described in Table XVIII. Table XIV. Columns Common to All Types of Data _______________________________________________________________________________ Item Format Columns Explanation _______________________________________________________________________________ Date and time(UT) F8.5 1 - 8 Day of month and decimal fraction at mid-point of observation Serial number I2 10 - 11 Line number in the table Filter name A4 13 - 16 Short-hand name wavelength I4 18 - 21 Central wavelength [A] width I4 23 - 26 FWHM [A] _______________________________________________________________________________ Table XV. Columns for Magnitudes (DAT-TYPE = BROADBAND) ________________________________________________________________________________ Item Format Columns Explanation ________________________________________________________________________________ Upper limit code char 28 '<' indicates that the result in the following field is a 3-sigma limit Magnitude F7.3 30 - 36 Reduced magnitude error F5.3 38 - 42 One (1) sigma [mag]; omitted if previous field is a limit Aperture size F5.1 44 - 48 Diameter [arcsec] Radial offset I4 50 - 53 Radial distance between center of aperture and the peak brightness of the comet [arcsec] Angular offset I3 55 - 57 Angular direction [deg] (eastward from north) of the radius vector between the center of the aperture and the peak in brightness Integration time I4 59 - 62 Integration time [s] Airmass F5.3 64 - 68 Airmass at midpoint in time, usually as quoted by observer ________________________________________________________________________________ Table XVI. Columns for Fluxes from Narrowband Filters (DAT-TYPE = NARROWBAND) ________________________________________________________________________________ Item Format Columns Explanation ________________________________________________________________________________ Upper limit code char 28 '<' indicates that the result in the following field is a 3-sigma limit Log Flux F7.3 30 - 36 Logarithm (base 10) of the flux See Section IV for details error F5.3 38 - 42 Error of log10 of flux Aperture size F5.1 44 - 48 Diameter [arcsec] Radial offset I4 50 - 53 Radial distance between center of aperture and the peak brightness of the comet [arcsec] Angular offset I3 55 - 57 Angular direction [deg] (eastward from north) of the radius vector between the center of the aperture and the peak in brightness Integration time I4 59 - 62 Integration time [s] Airmass F5.3 64 - 68 Airmass at midpoint in time ________________________________________________________________________________ Table XVII. Columns for Polarimetry (DAT-TYPE = POLARIMETRY) ________________________________________________________________________________ Item Format Columns Explanation ________________________________________________________________________________ Polarization type A2 28 - 29 'CR' => right circular 'CL' => left circular 'LN' => linear Polarization value F5.2 31 - 35 Degree of polarization [%] error F5.2 37 - 41 One (1) sigma [%] Position angle F5.1 43 - 47 For linear polarization, the position angle of the electric vector [deg] clockwise from the plane of scattering (-45 to +135) error F4.1 49 - 52 One sigma Aperture size F5.1 54 - 58 Diameter [arcsec] Radial offset I4 60 - 63 Radial distance between center of aperture and the peak brightness of the comet [arcsec] Angular offset I3 65 - 67 Angular direction [deg] (eastward from north) of the radius vector between the center of the aperture and the peak in brightness Integration time I4 69 - 72 Integration time [s] Airmass F5.3 74 - 78 Airmass at midpoint in time, usually as quoted by observer ________________________________________________________________________________ Table XVIII. Format of the Printed Archive and the Index Table ________________________________________________________________________________ Header Value/Explanation ________________________________________________________________________________ GENERAL SECTION Date(UT) Date of the middle of observation (in UT day and fraction) PPN# Photometry & Polarimetry Network number--a unique number for each FITS file Filter Filter name Lambda Central wavelength of filter [A] Delta lambda FWHM of filter [A] ApDia Aperture diameter [arcsec] ExpS Integration time [s] FLUXES (NARROW-BAND PHOTOMETRY) LogFlux Logarithm (base 10) of the flux and uncertainty; '<' indicates a limit POLARIMETRY Type Polarization type, 'CL' => left circular, 'CR' => right circular, 'LN' => linear. Polar Degree of polarization [%] and uncertainty (one sigma) Angle For linear polarization, the position angle of the electric vector [deg] clockwise from the plane of scattering and uncertainty MAGNITUDES (BROAD-BAND PHOTOMETRY) Mag Magnitude in a photometric system and uncertainty; '<' indicates a limit GENERAL SECTION (CONT.) Offset rho Radial distance between center of aperture and the peak brightness of the comet [arcsec] Offset theta Angular direction [deg] (eastward from north) of the radius vector between the center of the aperture and the peak in brightness. Airm Airmass at mid-point of observation. System System codes '5oooxxyy', 5 = our net ooo = IAU observatory code xx = telescope code yy = 01 photometer 02 CCD 05 polarimeter Observer Name(s) of observer(s) Notes Comment notes ________________________________________________________________________________ VI. ACKNOWLEDGEMENTS The extensive program to establish a net of standard stars for the narrow-band photometric system would have been impossible without the assis- tance to the Discipline Specialist Team from P.V. Birch (Perth Observatory, Australia), A. Gutierrez-Moreno (Universidad de Chile, Chile), R.L. Millis (Lowell Observatory, U.S.A.), H. Moreno (Universidad de Chile, Chile), D.G. Schleicher (Lowell Observatory, U.S.A.), and E. Wenderoth (Universidad de Chile, Chile). The Discipline Specialist Team would like to particularly thank all the observers listed in Table XII for their efforts to make this archive a success. In nearly all cases, their efforts were totally voluntary, unsupported financi- ally by the IHW. REFERENCES A'Hearn, M.F. (1978). Astrophys. J. 219, 768. Hardorp, J. (1978). Astron. Astrophys. 63, 383. Hardorp, J. (1980a). Astron. Astrophys. 88, 334. Hardorp, J. (1980b). Astron. Astrophys. 91, 221. Hardorp, J. (1982). Astron. Astrophys. 105, 120. Hayes, D.S., and Latham, D.W. 1975 Astrophys. J. 197, 593. Hsu, J., and Breger, M. (1982). Astrophys. J. 262, 732.