[Aavso-photometry] DSI Pro Photometry text by Arne Henden, published in S&T

[Wolfgang Renz]

I found the S&T article inset text (I knew I have it somewhere):

"Preliminary Science Tests of a DSI-Pro
by Arne A. Henden

I’m continually asked the question “Can I do photometry with a
brand X CCD?”  I decided about a year ago to pursue the answer
in a scientific manner, and have gotten one grant and some vendor
loans of inexpensive CCD cameras. The DSI-Pro was one of these,
with John Hoot of Software Systems Consulting providing me an
early prototype late last year. 

I have been favorably impressed with this camera. It has low readnoise
(about 6-7 electrons), very low dark current (2.5electrons/sec/pix at
36F), and excellent cosmetic quality.  The prototype had a fair amount
of amplifier glow that could be subtracted cleanly if a dark frame was
taken at the same ambient temperature.  The camera gain is set such
that the system is reasonably linear to 50K ADU.  However, since ABG
cameras usually become nonlinear about half-well capacity, this gain
setting means you lose  the top end of the dynamic range in an individual
exposure; I much prefer the camera gain to be set to reach the pixel
saturation limit.  Displaying the non-square pixels makes star images
elongated but this does not affect the photometry.

On-sky tests show excellent blue response (I was able to get U-band
images).  A 30-second V-band image on the 1.0m telescope had a
faint limit of V=19.3, not much different from our science cameras.
A preliminary reduction of a 2-hour time series on my favorite cluster
(NGC7790) shows 4mmag photometric errors over the entire 245
frame series, with the delta Scuti NSV 14781 0.1mag light curve
amplitude easily resolvable.

I would definitely recommend this low-cost camera as an entry into
astronomical photometry, especially once other software packages
start supporting it."


Other reviews:
- Cloudy Nights Discussions
  Dsi Pro for Variable Star Photometry
  <http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/577365/>
  DSI choice: Meade DSI, DSI pro, Orion DSI? which
  <http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/1122736/>
- Jeff Hopkins
  Astronomical Photometry with a DSI Pro
  DSI Modifications
  http://www.hposoft.com/Astro/DSI/DSI.html

Clear skies
  Wolfgang

-- 
Wolfgang Renz, Karlsruhe, Germany
Rz.BAV = WRe.vsnet = RWG.AAVSO