From: Milton Aupperle <milton@outcastsoft.com>

Date: October 8, 2005 12:23:13 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] First Astro IIDC shot

Hi Duane;

Nice Image for a first night out.

I was out last night until 3 am shooting Mars with my MAK 127 mm 5.1" scope. Initially (1:00 am MST) turbulence was a bit better than average, but by 1:30 am it became "bad" (Mars would suddenly turn into elongate 50 arc second burs between subsequent frames at 30 fps). I'm guessing the Jets Stream swung north again and "sat" on top of me.

One thing to keep in mind about using a barlow is that each time you double the magnification, you reduce the light intensity by a factor of 400%.

1x = brightness of 100 units = exposure time of 33 ms

2x = brightness of 25 units = exposure time of 132 ms for same brightness

4x = brightness of 6.25 units = exposure time of 528 ms for same brightness

To compensate, you need to increase the exposure time (or gain) for the magnification your using and with your 5x barlow you need a lot more to get a usable image.

HTH..

On 8-Oct-05, at 3:53 AM, Duane wrote:

Here is my first image with Astro IIDC.

http://homepage.mac.com/deal/firstmars.jpg

I couldn't get my 5x powermate to show anything, so I ended up using my Celestron 2x

barlow. Not a whole lot of magnification. I'll have to work on that. (any help is welcome)

Thanks,

Duane

Orion 100ED, 2x barlow, Unibrain Board camera.

Milton J. Aupperle

President

ASC - Aupperle Services and Contracting

Mac Software (Drivers, Components and Application) Specialist

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

Calgary Alberta Canada T2R0N5

1-(403)-229-9456

milton@outcastsoft.com