From: Milton Aupperle <milton@outcastsoft.com>

Date: April 30, 2008 10:33:22 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Jupiter..

Hi Mark;

On 30-Apr-08, at 6:31 PM, Mark Gaffney wrote:

Hi everyone, Last night I got my first view of Jupiter coming back

from my IS DBK 21A F04.AS to the screen. I`ve had troubles with

focusing which has been solved pretty well by putting my old LCD

monitor out near the focusing knob on the scope. I don`t have a lap-

top which I know a lot of you have, so have had to use a long VGA

cable. Jupiter didn`t come into view until I`d done some nudging back

and forth with the hand control on the Celestron 4SE I was using and

set the exposure to 533.33 ms. I must read up in the manual what this

means exactly and any other advice! I didn`t manage to bring the

"stripes" into view but was pleased I`d finally been able to find an

object smaller than the moon.

Your 533.33 ms exposure time (ms is milliseconds, so 533.3 ms is 0.533 second exposures) is too long to see anything except the bright disk.

Using a long exposure like that is useful to get an object centered and focussed when your not sure how much your focus is out. Once you get it roughly in focus, you decrease the exposure time and brightness until you begin seeing details on the disk.

However 533.33 is way too long an exposure to see any details on the disk, especially jupiter. At prime focus (say 2,000 mm or less) with a C8, probably 33 ms (0.033 second) exposures is all you need and even that might be too much for a 10 inch scope.

Unfortunately, about the only way your going to get proper exposures and fine tune the focus at the same time is to lug the Mac and the VGA LCD outdoors beside your scope.

Lastly, one thing I like to do is adjust my finder scope so that it and the camera point at the same thing. So once you get Jupiter perfectly centered in camera field of view (FOV), adjust the finder scope so the cross hairs are right on it. Then the next time you go looking for a target, it will be likely be right in the cameras FOV.

Hope some of this helps..

Milton J. Aupperle

President

ASC - Aupperle Services and Contracting

Mac Software (Drivers, Components and Application) Specialist

#1005 - 815 14th Avenue. S.W.

Calgary Alberta T2R0N5

1-(403)-229-9456

milton@outcastsoft.com