Re: [APML] Pushing & Mars

Monday night I attached my newly purchased and modified Quickcam 4000 to my C11 on a CGE mount. Once I got Mars centered, all I got was the brightest blob you ever saw, with refraction spikes. I tried modifying several of the settings for the camera such as shutter speed, brightness, gamma, gain, etc. Still nothing but a bright blob - no details. So I put in my barlow lens. That made quite a difference - sort of. At least it was not a bright blob anymore.

I started the recording process. Just to give you an idea of the effect of atmospheric turbulance the image jumped around in the frame like a dancer. It would actually shift by up to 10 pixels at a time. It did stay fairly well centered, it was just very jittery. And I could not get a 'sharp' focus.

Keep in mind that I am at lat 47 + a few minutes. So Mars is rather low to the horizon, about 25-30 degrees up.

I also found that I must have accidentally touched the plastic covering the ccd chip. I could see fingerprint ridges in the image. This outing was a test of the webcam to see how to work it with something like Mars. I will take it with me to New Mexico at the end of the month where I will pop it into the telescope that I will use there. Should have nice dry still air. :)

Walter Willis
Life without chocolate is too terrible to contemplate

----- Original Message -----

From: Steve.Holak@bcitpa.com

To: Discussion of Film Astrophotography

Sent: Wednesday, August 20, 2003 8:43 AM

Subject: Re: [APML] Pushing & Mars

Gary,
I image Mars successfully with the "webcam / stack the good frames"
method ( http://mywebpages.comcast.net/sholak/CRO/8-15red.jpg ) , and
from both my previous attempts with film and digital cameras have found
that trying to get a decent image of Mars with methods other than the
webcam approach is unlikely; the atmosphereic turbulance blurring an image
is happening just too quickly for a film shot, unless you get extremely
lucky: out of 1000 frames in a webcam video shot at 15-30 frames per
second, I find only about 1 in ten is usable, and even in those there is
some blurring, distortion, and noise introduced by the atmosphere that
(fortunately) tends to get cancelled out in the stacking process.

If you do intend to just try the film appoach, then I recommend the fastest
ASA possible (with tolerable grainyness), and taking as many pictures as
possible in a short time with the fastest exposure possible, and hope to
catch a lucky, still moment.