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blink138
10-11-2012, 04:36 PM
hello members
on a GEM when people say have it slightly biased to the east side do they mean when the counterweights on the east or the OTA?
pat
Geoff45
10-11-2012, 05:34 PM
They mean that whatever is on the east side is heavier. Doesn't matter if it's the scope or the counterweight.
mithrandir
10-11-2012, 06:20 PM
You can set up an automated system like this (http://www.flickr.com/photos/averen1/6166580021/in/set-72157627714693494/), except for the southern hemisphere the guide roller goes on the other side and the cord wrap goes the other way.
blink138
10-11-2012, 06:48 PM
oooooh.......ok guys i did not realise that
so it really would need a rebalance when it goes on the other side then?
that could be inconvenient!
pat
Geoff45
10-11-2012, 11:03 PM
Yes it is inconvenient, but if you plan ahead it's not really a problem. Just image on one side of the meridian. Say you do the west. Pick up an object as it crosses the meridian and image for 1-3 hours. At the end of the exposure your next object will (hopefully) be crossing the meridian ready for imaging.

However, you can avoid this rigmarole by throwing money at your equipment. A Paramount or Astro-Physics mount will track beautifully as you cross the meridian if your mount is balanced or even somewhat unbalanced, either east or west.
Geoff