Club d'Astronomie de Lyon-Ampère

Pixel 211 CCD Camera

...work in progress...


Pixel 211 Camera :

This is a low cost CCD camera. See advertisement sometimes in Sky&Telescope (it runs at $375 or so at the moment). Here are the main specifications:


La caméra Pixel211 et ses accessoires

You can contact Pixel at:

Note that I modified the original software (v1.30) and added the following:

You can download the latest version here: Pixel v2.01. Thank you report bugs to me.

 

Some Images!!! :

Messier 11

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3).
Date: June 3rd, 1995 - Blue Canyon (California) during the 1995 Star-BBQ party!
Exposure: 4", 8", 16", and 32"; unguided
Processing: Gamma corrected (LView)
This picture of one of the best Open Cluster in the sky shows how the CCD react with different exposure time.
Those are my first exposures with the Pixel 211 CCD camera and my Celestron Ultima 8 polar aligned.
Blue Canyon is a very nice place in the Sierras, close to Sacramento. The Scramento Valley Astronomical Society (SVAS) was organizing their annual Star-BBQ when I took those pictures. It was quite a success as more than 200 people (50 telescopes) were attending this party!

Messier 11

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3).
Date: July 3rd, 1995 - Blue Canyon (California)
Exposure: 30"; unguided
Processing: Dark Frame removed

Messier 15 (Pegasus)

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3). Date: July 2nd, 1995 - Blue Canyon (California) Exposure: 32"; unguided Processing: Dark Frame removed

Messier 71

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3). Date: June 3rd, 1995 - Blue Canyon (California) Exposure: 64"; unguided Processing: Dark Frame removed and Gamma corrected (LView)

Messier 27, Dumbell Nebulae

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3). Date: June 3rd, 1995 - Blue Canyon (California) Exposure: 1'; unguided Processing: Dark Frame removed and Gamma corrected (LView)
This picture has been taken the night before the 1995 Star-BBQ party of the Sacramento Valley Astronomical Society (SVAS) - more than 200 people, and 50 telescopes! This was one the first exposures taken with the Pixel 211 and my Ultima 8 polar aligned. Unfortunatly, I discovered that it was not tracking so easily, and that CCD doesn't allow guiding errors! My Celestron Ultima 8 has some Periodic Errors that does not allow more than 2' unguided exposures (60" is the most reasonable).

Messier 57, Ring Nebulae

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3). Date: June 3rd, 1995 - Blue Canyon (California) Exposure: 2'; unguided Processing: Dark Frame removed
This picture has been taken the night before the 1995 Star-BBQ party of the Sacramento Valley Astronomical Society (SVAS) - more than 200 people, and 50 telescopes! This was one the first exposures taken with the Pixel 211 and my Ultima 8 polar aligned. Unfortunatly, I discovered that it was not tracking so easily, and that CCD doesn't allow guiding errors! I noticed that my gear had several errors that repeats every four minutes. I was able to find a 2 minutes 'window' to take this shot. I tried to program the PEC, but it didn't work properly at this time - still need some practice!

NGC7331 (Pegasus)

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3). Date: July 3rd, 1995 - Blue Canyon (California) Exposure: 15'; guided Processing: Dark Frame removed
This galaxy is so large that it does not fit in the small TC211 chip! Very similar to the actual visual observation made the same night with a 17" telescope. See the image of the Stephan's Quintet taken during the same night - they are both in the same area of the sky.

NGC7332/39 (Pegasus)

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3).
Date: July 3rd, 1995 - Blue Canyon (California)
Exposure: 500" (8'20"); guided
Processing: Dark Frame removed
Interesting group of two galaxies. This view is very similar to the actual visual observation made the same night with a 17" telescope.

NGC 770/772 (Aries)

A couple in the sky; NGC772 is easy to find in Aries, and is very interesting to image; Do you notice the extended arm in this 4'short exposure, Dark Framed removed? Telescope: Celestron 8 (with focal reducer/corrector f/6.3). Date: Saturday October 28, 1995 - CALA observatory. Exposure: 4', unguided Processing: Dark Frame removed.

Stephan's Quintet (Pegasus)

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3).
Date: July 3rd, 1995 - Blue Canyon (California) Exposure: 15'; guided
Processing: Dark Frame removed
One of my best shot with the Pixel CCD camera. How many can you count on this picture?
This view is very similar to the actual visual observation made the same night with a 17" telescope.
See the NGC7331 picture taken the same night.

 

NGC70 group (Andromda)

A superb group of galaxies near Alpha Peg; we can count at least four galaxies... Telescope: Celestron 8 (with focal reducer/corrector f/6.3). Date: Saturday October 28, 1995 - CALA Observatory. Exposure: 5', guided Processing: Dark Frame removed.

Messier 15 (Pegasus)

Telescope: Celestron Ultima 8 (with focal reducer/corrector f/6.3). Date: July 2nd, 1995 - Blue Canyon (California) Exposure: 32"; unguided Processing: Dark Frame removed

 

Basic CCD Processing :

1- Prepare the Dark Frame

Take several pictures with the telescop cover on, if possible just before and just after the target picture: this will reduce the impact of temperature change on the dark frame. As you see on the picture above, adding two dark frame reduce the noise level. Of course, you can average more if you want!

Dark frame picture should have the same exposure time thatn the target picture; this will simplify the processing. Several program exist on the market to process your images. One can note SuperFix which is easy to use, not very expensive, and work very good with Pixel images. AIP, from Richard Berry and sold in Sky&Telescope, is also an easy to use and basic program. My favorite though is QMips32 from Christian Buil. Very powerful, sometime complex, this program can do almost everything!

2- Prepare the Flat Field

Each pixel does not have the same dynamic. Also, some dust can be on the CCD chip. In order to get ride of those defects, it is necessary to do a flat field. To do so, the best is to take images of the twilight (same configuration as for the pictures: do not move the camera or the focus position in between). Of course, you need to remove a dark frame associated with flat field to obtain the final flat field, as shown in the following picture:

3- Pre-processing

Once you have the dark frame, the flat field, and the image of your object, you are ready for the pre-processing:

First, substract the dark frame; then divide by the flat field... It is as easy as this, and as you can see your image will be much nicer!!!

 


!!! I would appreciate any comments. Send them to Olivier THIZY !!!