From: Milton Aupperle <milton@outcastsoft.com>

Date: July 20, 2009 12:13:47 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] First light 16" Truss Dob Jupiter imaging

Hi Jim;

On 20-Jul-09, at 5:42 AM, jimchung2338 wrote:

Hi all,

Firstly, no images of the impact disturbance since it was facing away from me this morning.

http://tech.groups.yahoo.com/group/Astro_IIDC/files/Planetary/TrussDobJupiter.jpg

It would have been just setting. From what I can determine it's about + 90 to 100 degrees from the GSR's edge. I got clouded out, but even at 3:45 am when Jupiter is at it's peak, it was only 22° above the horizon anyhow and the Jet stream is over top of me again.

A few months earlier I had fantasized about planetary imaging with a light bucket on a budget like a 16" Lightbridge.  You could have decent image size and high capture rate to freeze seeing.  As it happens, a local observer was selling his 16" truss dob sans optics for an unbelievable price as he was moving up.  I found an old 16 f4.5 Meade Starfinder dob mirror which I had locally recoated and also sourced a used secondary.  The second part of the equation is building a rudimentary tracking platform since its pretty hard to nudge this beast of a scope and keep it centered on a small 640x480 chip.  Due to the method by which I've attached the drive motor to the platform there is a degree of occasional fine tuning of the motor speed to keep the image centered so its busy but doable.  And since I only eyeballed the polar alignment of the platform, every 5 minutes or so I need to adjust the DEC/Alt by tapping the truss a few times with my knuckles!

Very cool. I can't wait until you get it polar aligned and all dialed in. Your moon shots will be interesting too :)

Here's what it looks like:

http://tech.groups.yahoo.com/group/Astro_IIDC/files/Other/TrussDobPics.jpg

Jim