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

Date: May 8, 2011 9:10:22 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Dob on a GEM


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