Improved Setup in 2003

The images taken in 2003 were with a new mount (Gemini G-41), new CCD (second-handed Genesis KAF1602E), and new filterwheel (Astronomik 34mm). The filters used include the Astronomik LRGB set, and their Hydrogen-alpha and Oxygen-3 narrow band filters (all 34mm clear aperture). IDAS LPS and Sirius Optics MV-1 Mini-violet filters were also use when appropriate. However, my work horse was still my Celestron 8" SCT piggyback with a Celestron C80 80mm F11 refractor. The autoguider was a second-handed SBIG ST-4. A newly acquired Borg 76ED replaced the C80 for wide-field imaging.

I have modified my C8 to stabilize the primary mirror, but there still some  mirror movement during long exposures. But except when crossing the meridian the stacked images from 20minutes sub-exposures turned out quite OK. Recently I bought a C11 from Astromart, and it got a primitive 3 point mirror support system installed by previous owner. Basing on this, I added further a T6061 aluminium plate to the mirror cell so that the mirror will not be distorted by the supporting rods.

The Genesis came with an Engineer grade KAF-1602E chip, but I cool it to -20C with water cooling (by a water chiller running at 14C). The higher quantum efficiency of the Kodak CCD (than Sony ICX083/ICX423 in MX916) at around 650nm is better suit for Hydrogen-alpha imaging.

Software I mainly use Astroart, AIP4WIN and Sigma, but since Astroart still didn't have the driver for the USB interface of Genesis when I bought it I purchased MaximDL for acquisition of the CCD images only.

I use AIP4WIN to calibrate the light frames, and use its batch processor for deepsky to 2x blowup and auto-align. Its image enhancement tools are also good and usually auto-detect the appropriate setting for each image. Its Richardson-Lucy (slow version) deconvolution with the high frequency only option is especially useful to enhance details.

I use the Astroart for acquisition of image from Starlight Xpress MX916, and its batch processor for images calibration and autoalignment, and to combine RGB or LRGB colour image. Its brightness adjustment and image transfer curve is also good and flexible enough for me instead of using Photoshop.

Sigma is very effective in minimizing noise when combing multiple sub-exposures. I use it to prepare light, dark and flatfield frames. A by-product of it is that I can mix light frames with less than good tracking with those of good tracking and still get tight, round stars.

 

Closeup:

Overall equipment in the morning

Wide field imaging with the piggybacked Borg 76ED

Northern view of my site (Polaris is just out of the view)

Genesis CCD with Astronomik Filterwheel

Old MX916 CCD on C8, ST-4 on C80 refractor

Open view of Astronomik Filterwheel (before filters were installed)

 

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