U-42 Imaging Camera
The main imaging camera for the 20-inch telescope is an Apogee Alta U42-UV high performance cooled CCD with a D10 camera body that enables -40C below ambient air cooling.
In the imaging plane of the 20-inch telescope the CCD images a square about 20 arcminutes on a side with 0.25 arcseconds/pixel.
Here is a gallery containing pictures taken with this camera.
CCD
E2V CCD42-40
2048x2048 pixels (13.5 microns square)
Full linear well depth 100k electrons
Gain = 1.4 adu/electron
Filers/Gratings
Johnson UBV + Cousins R,Ic + Clear par-focal
High through-put manufactured by Astrodon.
http://www.astrodon.com/store/p10/Astrodon_Photometrics_UVBRI_Filters.html
Star Analyzer (SA) 200 grating
For slit-less field spectroscopy.
Grating with 200 lines/mm
On 20-inch yields spectra with 1.35 nm/pixel
Photometric Calibration/Transformations
Since 2013 we have imaged star cluster M67 in February or March with all filters and used those images to compute photometric transformation coefficients with the photometry of the cluster by A. Henden. The coefficients have remained stable over that period of time. The table below holds those coefficients. Note that they are small and will not matter except for stars with extreme colors -or- when the highest precision is required.
Last updated 190515