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GoTo alignment from obstructed site

Started by Ryoung362, 10/10/2007 02:44AM
Posted 10/10/2007 02:44AM Opening Post
I'm kicking around the idea of getting either a GoTo scope, a GoTo GEM for an existing scope, or an Orion Intelliscope Dob for use at home. Due to buildings and trees, I'm restricted to a little more than the Southeast quadrant of the sky. I can go a little past the zenith into the Southwestern quadrant, but not far....maybe 5 degrees reliably. Other positions in the yard give me a little more sky but expose me to the lights from passing cars, porch lights, etc.

Besides the Intelliscope dob, I'm considering a Celestron CPC, Meade LX90, Celestron AS-GT GEM, and an Orion Skyview Pro GoTo GEM. Can any of these be aligned for reliable GoTo (or Push To) operation using stars in only one quadrant of the sky? What are the requirements for choosing alignment stars with the present computerized mounts?
Bob
Posted 10/10/2007 03:49PM #1

I have an 10" LX200 classic.. to get good alignment, you need to use multiple stars, preferably in different parts of the sky. Trying to align on two stars in the SE for example probably wouldn't yield a very accurate alignment. Though it may work.

But.. if you are looking for a newer scope. The newer Meade LX200GPS (I think even the LX90..and other models) have 'AutoAlign' as they call it. Which does not require star alignment. You basically turn it on, the GPS gets your location, aligns you, and you are set to go. I have never used this, or seen it in action personally. So hopefully someone else can elaborate on its accuracy. You may be able to autoalign, then sync on a single alignment star to get better alignment. I'm guessing.

I'm not sure how a GoTo GEM (with GPS) from another maker would fare.

You should probably consider such an autoalign scope for use at your location. If you keep the size of the scope managable, you may even be motivated to pickup your gear and make excursions to more open/darker skies on occasion. Be sure to consider that option. My 10" LX200 is somewhat of a monster to move around. Thus on nights where I would have loved to observe, it sat in storage due to time to setup and move. As a result, I recently finished construction of an observatory... now I can finally get some observing in on a regular basis. Next I figure out a portable scope solution. And something EASY to move and fun to observe with smile

Unfortunately my experience is rather limited with other makers, so I can't provide much info on your other options. Though I suspect I will upgrade to a GoTo GEM (G11) in the next year or two as I am into photography. Planning to keep the LX200 OTA though.

Hope this helps a little bit.
Posted 10/10/2007 04:20PM #2
Bob,

This is a tough one. First, can you see Polaris? If this is a problem, then you may have a real challenge. Hopefully, if you can get a good shot at polaris and get a GEM, then some of the goto/pushto computers only need one alignment star. As an example, I have an Argo Navis and with "exact polar alignment" I only need one star. "rough polar alignment" usually takes two stars and this is normally a problem for me due to the multiple trees in my view.

- Peter