From: "jimchung2338" <jim_chung@sunshine.net>

Date: July 20, 2009 5:42:57 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: First light 16" Truss Dob Jupiter imaging

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

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!

Here's what it looks like:

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

Jim