From: "doobisary" <tjp314@pacbell.net>

Date: May 23, 2011 10:59:54 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Dob on a GEM

Nice work!

Of course, a Dob on a GEM isn't a Dob anymore (and that's a good thing!  ;oD)

-Tim.

--- In Astro_IIDC@yahoogroups.com, "jimchung2338" <jim_chung@...> wrote:

Most of you will know that I've been doing my planetary imaging with a 12" Skywatcher collapsible dob using Meade Autostar and motors to drive the alt/az dob base.  The problem is that it takes constant corrections to keep the image centered as you can't rely on Autostar in alt/az mode at high focal lengths.

Since CSC was predicting very good seeing last night, I wanted to be able to monitor the seeing over two hours and capture data when the seeing peaked.  Doing this with the dob mount would have been exhausting so I designed a simple oak fork mounting system to place the dob onto my EQ6 mount.  Definitely a two man job lifting and maneuvering the 60lb OTA into the dovetail saddle.  I needed over 55 lbs of counterweights to balance necessitating a quick visit to Sears just before closing time to get an additional 20lb free weight.  

It worked well and I was able to track Saturn from 11pm to 1AM with only very minor corrections every 10-15 minutes.  Unfortunately the seeing was never that good so the imaging was a bust.

http://dl.dropbox.com/u/4852049/DOBonGEM.jpg

Jim