PC23C (Video camera) and Jupiter, Success but Questions

I finally got some fairly decent shots of Jupiter with my
Supercircuits (SC) video camera, pc23c; however, this leads to more
questions.

The camera has an electronic shutter switch. Normal operation,
according to SC is with the switch on. That's what I was using but was
not getting anything useful in the way of images for Jupiter. I could
even capture the moons, but they were not pin points. I happened to
turn the switch off, and the displayed images dimmed, and I could
focus to detail on Jupiter. However, I lost the moon images. What is
the difference electronically with the switch positions.

Actually, I could see the moons faintly in the off position, but when
I captured them and played them back they were absent. Is there some
difference between the way images are captured and displayed (in just
normal viewing mode--not the playback after capturing)?

It's certainly a lot easier to focus Jupiter with the switch off. When
the switch is on, the moons are not pin points. They look like they've
been smeared around looking like an asterisk. I would think that's
blooming, correct?

I noticed when I used a barlow and had a big image of Jupiter that
dirt on the ccd was a lot more apparent. I think I spent a good 30
minutes cleaning it off. A few specks remain, and I'll work on them
today. It's easier to shoot a white background during the day, so I
should be able to catch them all. They were surprsingly difficult to
remove with my normal mix of materials for cleaning telesope lenses.
--
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet, Nevada City, CA)
-- GMT-8 hr std. time, RJ Rcvr 39° 8' 0" N, 121° 1' 0" W

The human body is 2/3rds water.
Think about that the next time you pee.

Web Page: home.earthlink.net/~mtnviews
sierra_mtnview -at- earthlink -dot- net
Imaginarium Museum: home.earthlink.net/~mtnviews/imaginarium.html

On Thu, 11 Mar 2004 00:40:42 GMT, "W. Watson" wrote:

I finally got some fairly decent shots of Jupiter with my
Supercircuits (SC) video camera, pc23c; however, this leads to more
questions.

The camera has an electronic shutter switch. Normal operation,
according to SC is with the switch on. That's what I was using but was
not getting anything useful in the way of images for Jupiter. I could
even capture the moons, but they were not pin points. I happened to
turn the switch off, and the displayed images dimmed, and I could
focus to detail on Jupiter. However, I lost the moon images. What is
the difference electronically with the switch positions.

I thought you had modified your camera for manual gain control? It is very
difficult to get good results with an unmodified auto AGC camera like the PC23C.
For planetary imaging, what you need is the ES off (that gives you a fixed
shutter speed) and a low gain.


Actually, I could see the moons faintly in the off position, but when
I captured them and played them back they were absent. Is there some
difference between the way images are captured and displayed (in just
normal viewing mode--not the playback after capturing)?

There could be some difference- you are seeing the analog signal and the dim
stuff may not be captured. You can't really get a single image with both Jupiter
and its moons properly exposed- the brightness difference is just too much for a
typical 8-bit digitizer. Take two images, one at high gain and one at low, and
stack them.


It's certainly a lot easier to focus Jupiter with the switch off. When
the switch is on, the moons are not pin points. They look like they've
been smeared around looking like an asterisk. I would think that's
blooming, correct?

Blooming looks like a line. What you are describing sounds more like an optical
aberration that is showing up when you are over exposed.


I noticed when I used a barlow and had a big image of Jupiter that
dirt on the ccd was a lot more apparent. I think I spent a good 30
minutes cleaning it off. A few specks remain, and I'll work on them
today. It's easier to shoot a white background during the day, so I
should be able to catch them all. They were surprsingly difficult to
remove with my normal mix of materials for cleaning telesope lenses.

The longer the focal length, the more you will see dust. Generally, there are
practical limits to how clean you can get (and keep) the CCD window. Correcting
your final image with a flat field exposure eliminates the dust from the image.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Yes, it is modified according to Paul Goelz's web instructions. I'm pretty confident
that it's working correctly. I visited him last fall and we checked it out.

I think what I need now is less wind. It was again fairly windy here last night.
Another bright image in the window would be helpful too to make registration better.
Trying to find a good area to drive the registration and stacking is not obvious. The
only choices are some part or all of Jupiter.

It looks like a light frame will be the ticket. I think I've reached the limit in how
clean I can get the glass protecting the ccd chip.

I recall from a few years back that a Watec was getting good press for meteor work.
Perhaps it has some features worth considering. It would be good to have a camera
whose shutter speed is controllable. I suspect that feature might come at a much
heftier price than that of the pc23c.


Chris L Peterson wrote:

On Thu, 11 Mar 2004 00:40:42 GMT, "W. Watson" wrote:


I finally got some fairly decent shots of Jupiter with my
Supercircuits (SC) video camera, pc23c; however, this leads to more
questions.

The camera has an electronic shutter switch. Normal operation,
according to SC is with the switch on. That's what I was using but was
not getting anything useful in the way of images for Jupiter. I could
even capture the moons, but they were not pin points. I happened to
turn the switch off, and the displayed images dimmed, and I could
focus to detail on Jupiter. However, I lost the moon images. What is
the difference electronically with the switch positions.


I thought you had modified your camera for manual gain control? It is very
difficult to get good results with an unmodified auto AGC camera like the PC23C.
For planetary imaging, what you need is the ES off (that gives you a fixed
shutter speed) and a low gain.

.... snip