Lowell Raw Data Collection Overview

Data Abstract
=============
We obtained images of the (65803) Didymos system and supporting calibration
images with the Lowell Discovery Telescope (LDT) through a VR filter. These 
images were taken in order to determine the orbit period of Dimorphos, the 
satellite of Didymos. This collection consists of the Lowell Raw Images.


Data Set Overview
=================
This collection consists of raw images of the (65803) Didymos system and
taken by the Lowell Discovery Telescope (LDT) through a VR filter. These 
images were taken in order to determine the orbit period of Dimorphos, the 
satellite of Didymos. 

The visible-wavelength, direct-imaging CCD for the LDT is called the Large
Monolithic Imager (LMI). LMI is a deep depletion, back illuminated monolithic
CCD with 6144 x 6160 pixels. The instrument was funded by the National Science
Foundation through AST-1005313. The camera is mounted in the direct through-put
port on the LDT instrument cube.

LMI images have a 12.3 arc minute square field of view with 15-micron pixels. The 
unbinned detector provides a pixel scale of 0.12 arcsec/pixel. The chip is 
commonly binned at 2x2 (0.24 arcsec/pixel) or 3x3 (0.36 arcsec/pixel). The 
chip is linear up to 65k ADU at the default gain of 2.89 e-/ADU. Read noise 
is 2.1 ADU per pixel and the readout time is 73 seconds for unbinned images, 
24 seconds for 2x2 binning, and 10 sec for 3x3 binning. The CCD quantum 
efficiency is 80% from 400-700 nm, and dropping to ~50% at 350 and 900 nm.

Fits images obtained with the Large Monolithic Imager (LMI) at the Lowell 
Discovery Telescope (LDT). Raw image data includes sky frames, bias frames, 
and flat fields. Dome flat fields are obtained by taking images of an 
illuminated white screen on the inside of the LDT dome. In some situations, 
additional observations of the twilight sky can be used as an alternate source 
for flat fields.

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.

lmi_<yyyymmdd>_<image counter>_<product type>_<version>.<ext> 

where: 
lmi refers to the Large Monolithic Imager instrument 
<yyyymmdd> year, month, day of observing session in UT

<image counter> four-digit image counter for observing session, reset for each 
night of observation, with counter starting at 0001.

<product type> defines product as one of the following types: raw or cal (for 
calibrated)

<version> the version of the data product. ex “v1” or “v2”.

<extension> the file extension. “.fits” for fits file format, “.xml” for the 
PDS label.