Las Campanas IMACS Raw Data Collection Overview Data Abstract ============= We obtained images of the (65803) Didymos system and supporting calibration images with the Inamori-Magellan Areal Camera and Spectrograph (IMACS) on the 6.5m Magellan-Baade Telescope at the Las Campanas Observatory (LCO). These images were taken in order to determine the orbit period of Dimorphos, the satellite of Didymos. This collection consists of the Las Campanas IMACS raw images, which include Didymos images and flat field images. Data Set Overview ================= IMACS is a reimaging spectrograph mounted permanently on the Magellan- Baade Telescope. The f/2 camera provides a 27.4 arcmin diameter field at a scale of 0.200 arcsec per pixel across the CCD mosaic array employing eight thinned CCDs manufactured by E2V to produce a 8192 x 8192 pixel mosaic. These CCDs are all 2K x 4K x 15-micron devices. Each detector thus provides a ~6.8' x 13.6' FOV. Unbinned full frame readout for the arrays is ~82 seconds, while 2x2 binning can reduce the readout to 29 seconds. A wide range of facility filters are available including the SDSS r' (also referred to as the "Sloan_r" filter) being deployed for this campaign. FITS images obtained with IMACS are written as individual frames for each of the 8 IMACS detectors in the f/2 CCD array. FITS images produced for this archive only utilize one of the detectors: CCD02. Raw image data include Didymos images and flat fields, with an overscan region on images used for bias-level subtraction. Flat field sources include dome flat fields obtained by taking images of a pupil-mask screen illuminated by telescope-mounted lamps, and observations of the twilight sky. Dark current is typically very low when imaging with IMACS, so dark frames are not used. Sidereal tracking was used and Didymos was allowed to move across the field. Naming Convention ================= Raw images consist of a single fits file containing the raw image and an associated XML file. They are named according to the following convention. iftc_. where: ift is the camera reference, referring to the IMACS f/2 camera is a four-digit image counter for observing session starting at 0001, reset for each night of observation c is the CCD number (1-8) within the mosaic array for the IMACS focal plane. For this dataset, only CCD 2 was used so it is always 2. is the UTC year, month, day of observation is the file extension. “.fits” for FITS file format, ".xml" for the PDS4 XML label Ex. ift1001c2_220702.fits is a raw image product for a 2022-07-02 observing session. It is the 1001st image generated on that UT date.