Article: Basic Setup Procedure for a German Equatorial Mount (GEM) Telescope

[iceman (Mike)]

Hi all

Trevor Hand (OneOfOne) has written a fantastic article, perfect for beginners, Basic Setup Procedure for a German Equatorial Mount (GEM) Telescope.

You can read the article from the IceInSpace Projects and Articles page, or directly from the link below:

Basic Setup Procedure for a German Equatorial Mount (GEM) Telescope

Thanks to Trevor for writing the article.

If you'd like to submit an article or other content to IceInSpace, please Contact Me.

[iceman (Mike)]

Article uploaded and this thread stickied.

[Michael V]

G'day Trevor,
May i congratulate you on your article. You have gone to a lot of effort, it all makes really good sense, and the pictures with their notations are really excellent.

Michael

[dannat (Daniel)]

looks terrific, well done trevor

[Jeff]

Great work Trevor, well explained and excellent pics/diagrams.

Cheers,
Jeff

[HarryD (Greg)]

Thanks Trevor

You have a knack of making the difficult seem so easy. This sort of info sure makes a new GEM owner feel more relaxed about their purchase.

Merry Christmas to you all.

[telecasterguru (Frank)]

Thanks for the great article. As a learner since given a little refractor with GEM for Christmas this article was invaluable to explain how to set up the mount but also why it is set up that way. I was totally confused as to why the south celestial pole was so important and now I understand.

Frank
Telecasterguru

[lacad01 (Adam)]

Great article! Will be picking up my new EQ6 tomorrow so this will definitely come in handy getting oriented

[clem]

I have tried and tried, but I can't get alignment right. I did the compass, I have calibrated the mount, I compensated for true south, I tweaked my latitude, and still, I couldn't get accurate alignment. First star is off the center of my finderscope, then the second star is way off, third one I couldn't see at all. What am I doing wrong? Is it me or is it the mount (EQ3-2) or the Synscan goto system? Heelp!!!

[OneOfOne (Trevor)]

You may want to post a new thread in the beginners area. This will bring it to the attention of people better, most may think your question is about the article than your alignment problems.

Unfortunately, you are not in Melbourne or I might be able to have a look. One thing that I have done myself, , on a couple of occasions is to plug the RA and Dec cables into the wrong sockets, have you checked these? The alignment goes absolutely nuts as you can imagine. My scope also goes nuts if the battery is almost flat, I doubt this is your problem though.

[John45 (John)]

Thankyou so much for this article. Being new to astronomy, I know that a good quality mount is very important, so I have just bought a Losmandy G8 and this explains absolutely everything that is required to set it up.

[Mutley (Paul)]

Thank you for this, My instruction manual that came with my scope might as well been written in Hungarian! This helped me out no end. Top article. Many Thanks

[mongol01 (Tim)]

Thanks to Trevor for such an in depth article for someone like me who has just purchased an ebay scope with a GEM. Unfortunately seeing has not been good since I received it, but still trying to get the thing adjusted and oriented properly. I have twiddled everything on the scope, the RA dial turns too. Must be able to calibrate it or something? I had set the Lat for Brisbane, I live about the same Lat, but west. The scale for Lat is that fine that I would be hard pressed to get within 1 deg. anyway. Could someone please explain to me about setting the RA? Very useful site, many thanks. Come on sigma octans! will find you soon.

[mongol01 (Tim)]

Many thanks to MangroveDutch for his advice re
gem setup. I feel I asked something reallly stupid. Will try youtube for more help.

[Brisbane (Joe)]

very informative Trevor,

saved to my favorites, user friendly and great pics/diagrams. I wish I had seen this a few years ago I would have spent more time viewing.

Joe

[ourkind (Carlos)]

This article should be included as a suppliment in all GEM packages!!

Thanks it was very helpful!!

[Douvie (John)]

Thanks Trevor,

I have a lot of reading to do. The documentation that came with my scope is confusing, and even more difficult to understand if one is a noob. At least your how-to explains the important details.

[brian nordstrom (As avatar)]

Thanks for your time and effort Trevor , a great artical .
Brian.

[julianh72 (Julian)]

At the risk of stating the obvious (and apologies if this has been mentioned numerous times before), I thought I would remind people that they probably own a really handy tool to help get a reasonably good visual polar alignment for their GEM mount, and they probably carry it with them everywhere they go.

It's your smartphone.

Pretty well all modern smartphones have a compass and inclinometer built-in - all you need is a suitable app to access the data. I use the "Smart Tools" app on an Android phone, but there are numerous similar apps on most smartphone platforms.

Here's how I do it:

Set up the tripod at the desired location. If your tripod doesn't have a spirit level bubble built in, lay your smartphone on the tripod platen, screen facing up, and use the spirit level app to get the platen as horizontal as practical.

Now install the GEM mount and counterweight, and put the scope on the GEM. Use the altitude dial scale to set the altitude of the GEM RA axis to approximately match your latitude, and point the GEM approximately south. Align the telescope tube to be parallel to the GEM RA axis, so that it is pointing approximately at the south celestial pole (where the GEM is pointing).

I now place my phone on top of the tube, screen facing up, and long sides parallel to the tube axis. My phone has a rubberized case back, and my finder-scope mounting bracket stops the phone from sliding off; you may need to do something to hold your phone safely. (An elastic band wrapped around the tube may be good enough.)

First, I get the altitude of the GEM set more accurately to my latitude using the spirit level / inclinometer app. The app reads to an accuracy of 0.1 degrees, so you should be able to get better than one degree precision pretty easily.

Next, I get the RA axis pointed to true south, using the compass app. (My compass app works with the phone held at any angle, and includes an automatic adjustment for the deviation between true north and magnetic north, so I don't need to do any mental gymnastics to get a south alignment of better than 1 degree.)

Voila! A visual polar alignment within about 1 degree or better on both axes in a matter of a minute or so.

[caj1311 (Cindi)]

As an experienced photographer, but a complete novice astronomer (wanting to get into astrophotography), I had quite a few "Aha" moments reading this article. I found the instruction manual for my GEM indecipherable, and the Northern Hemisphere approach did not help! Thanks heaps!