Some first night out experiments with my new SBIG237 CCD camera. The goal was to compare resolution, and light grasp with hypred Tech Pan film taken with similar instruments. While the full moon may not seem like the best time to be testing cameras, the cloud situation here in Payson is so severe lately, any chance was welcomed. Anyway, it simulates shots taken from city locations, right?
The special setup above was created just for the task. The primary instrument is a Meade 622 Comet Tracker, a 6 inch f/3.6 schmidt newtonian. For guiding, a separate guidescope was a meade 2045 schmidt cass, and as an alignment scope, a Vixen 80mm f/5 refractor.
The CCD has a sensor that is 640x480 resolution, and is called a Kodak "E" chip, for extreme blue sensitivity as well. The field of view in these shots is about 1/3 degree.
Clik on the thumbnails for a larger image.
Open clusters
Ste 1 in Lyra
One of the stars of the paralellogram of Lyra, delta Lyra is actually the center for an open cluster. This splashy group was at the zenith when I exposed five 60 second exposures in the "track and accumulate" mode with no guiding.
M11 in Scutum
To demonstrate the power of the 237 "E" chip, this is only a 30 second exposure with the 6 inch. Stars recorded are fainter than 15 minute exposures on hypered color film with the 12.5 inch!
M29 in Cygnus
Ive always liked the shape of this open cluster in the richest part of the Cygnus milkyway. Two 5 minute exposures were blended in Picture Window for reduced grain and a more photographic appearance. the shot was guided with an ST4 on the 4 inch guide scope. operating two CCD's at the same time was not as bad as it might sound...
NGC6939 in Cepheus
This very nice open cluster is only a degree away from the face on spiral NGC6946, and was well worth the five minute exposure. The cluster is deciededly asymetrical, with most of the stars lumped on one side.
NGC7160 in Cepheus
Two five minute exposures were blended to yeild this frame, what I thought was a cluster not worth looking at years ago in my 8 inch. This shot however shows a beautiful spray of at least 50 stars, and two main stars like car headlights.
Planetary Nebula
M27 in Vulpecula
The full moon was way up and blazing the sky to lightness when this pair of blended 5 and 10 minute exposures. I wouldnt even consider taking out my 35mm camera under such conditions! None the less, I got the ears clearly of this famous Dumbell Nebula.
M57 in Lyra
The famous ring nebula in Lyra is a good object for the full moon shoot. and, it has a surprise inside on the next shot! This is a pair of images blended in Picture Window. The first is five 1 minute exposures in the Track and accumulate mode, and the second five 2minute shots. I am trying to see what the difference is between direct guiding and track and accumulate.
M57 and IC1296 in Lyra
Same frame as above, but processed with a bit more contrast. Actually, this is the image that came up on the screen during the photo session with the auto stretch in place. The picture above was toned down a bit to look more natural. Look to the upper left of the overexposed planetary nebula in the center about an inch, and youll see a faint spiral galaxy, complete with arms just touching a faint star. That galaxy is IC1296. It is listed as 15.3 magnitude in the catalogs! I only just barely glimsed this galaxy with my 12 inch from super dark skies of Camp 613 a few years back. Yet there it is, recorded in what amounts to a five minute exposure with a six inch telescope, in total full moon....
M76 in Perseus
This is the faintest Messier object, so I gave it try as well. The tracking was giveing me troubles on this one, but notwithstanding, both lobes, and faint outer ears are easily recored in this blend of a 3 minute and 5 minute exposure.
Galaxies
M31 in Andromeda
Two shots of the Andromeda galaxy are shown here. The first, is a direct five minute exposure with the six inch, and shows the main desk and some dark lanes in the arms above. Compare this to the shot below.
M31 in Andromeda
The shot was taken with the track and accumulate mode, which is 5 sixty second exposures, automatically aligned in stacked by the CCD software as the picture was being taken. You can see obviously that they are not equivalent pictures. The direct shot, shows much more density in the nucleus, and good arm detail. On the other hand, the stack frames seen above while showing less detail in the dark lanes, does not burn out the nucleus quite as bad. This might be good for certain bright objects which have a large dynamic range. But also, the stacked picture has a higher noise background. You don't get something for nothing!
NGC404 in Andromeda
to five-minute exposures were combined by blending to give the shot of this peculiar object. The BrightStar, is beta Andromeda, a bright second magnitude star that overwhelms the shot. The street 00 star is the bleeding of the CCD frame on such a bright object. The galaxy however is to the upper left of the star image. This is always a challenging object visually because of its proximity to beta.
NGC6946 in Cepheus
Two 5 minute exposures were blended to yield this splendid shot of this face on Galaxy in Cepheus. The full-blown, was about 35 degrees up in East, and totally blowing away the sky. I couldnt even see this object in the finder scope, but I shot anyway.I was amused to get this image, come up on the screen showing a beautiful spiral galaxy was knots in the arms. I can't wait to shoot this during the dark of the moon.
I'm encouraged by these initial results, and will now pursue this new camera into the dark of the moon period. To be able to capture stars fainter than 16th magnitude during the full moon with a six inch telescope says something about your image acquisition system. I believe, this new CCD camera will be an excellent supplement to direct photography with hypered colored films. Anyway, it sure was a lot of fun!