CGEM polar alignment issues

[mikesim (Mike)]

I'm having some trouble getting a proper south polar alignment with my CGEM 1100 which means my 'goto' goes to 'nowhere'. I do the two star alignment (normally start with Alpha centauri as the double star is easy to identify) and then try and add a calibration star (which slews to nowhere so i need to move the scope around with the hand controller to find the star). Then I try the polar align routine (slew to a star and then use the dec/az screws to align the scope with this star). Still no luck. I manually slewed to Saturn for a great view but would like to be able to use the goto function so as to make finding items of interest a lot faster.
Help!

[Irish stargazer (John)]

Originally Posted by mikesim

I'm having some trouble getting a proper south polar alignment with my CGEM 1100 which means my 'goto' goes to 'nowhere'. I do the two star alignment (normally start with Alpha centauri as the double star is easy to identify) and then try and add a calibration star (which slews to nowhere so i need to move the scope around with the hand controller to find the star). Then I try the polar align routine (slew to a star and then use the dec/az screws to align the scope with this star). Still no luck. I manually slewed to Saturn for a great view but would like to be able to use the goto function so as to make finding items of interest a lot faster.
Help!

Hi Mike

You really need a minimum of three guide stars before doing a polar alignment. For the alignment, adjust the screws on the mount until the star is centered and select align until successful alignment is achieved. Make sure you lock down the mount at this stage. You then have to recalibrate you mount using another 3 (preferably 4) guide stars before your goto's will work again. I have a CGE mount with the same software. Its a bit tedious but it does work well. Use guide stars that are well seperated (east and west of the meridian) and not too near the pole.

John

[Gem (Grant)]

Sounds like something is wrong when you add the calibration star. Maybe I am wrong though...
After doing the two stars, press Enter and select the calibration star you want. The star is on the opposite side of the sky to where your two alignment stars are.

[Gem (Grant)]

Also make sure you roughly align the tripod using a compass or your own knowledge of the SCP before the two star alignment.

[Gem (Grant)]

Also... are you using the mount in "southern hemisphere mode"?

[mikesim (Mike)]

Thanks Grant and John,
Yes scope is in Southern hemisphere mode. I roughly polar aligned the scope using a compass and also the position of alpha centauri at true south per my stellarium map and the time.
Just to clarify though, when I go to my first and second alignment star I use the handset to get the star in the view to align and not the screws? (I thought the screws were only used for polar align).


Cheers
Mike

[Gem (Grant)]

Yes, use the handset for both the two star alignment and the calibration stars. Centre using finderscope, hit enter then centre in eyepiece then hit align for each.
When you go polar align mode, it will slew the scope to where the star you have chosen should be if the scope was polar aligned. If you are a bit out you might need to move the tripod not just the screws.

[mithrandir (Andrew)]

Originally Posted by mikesim

Just to clarify though, when I go to my first and second alignment star I use the handset to get the star in the view to align and not the screws? (I thought the screws were only used for polar align).

All Celestron GEMs work pretty much the same way. This method also works with my G11, and probably with any other GEM.

Don't believe the level in the mount without confirming it with a real level.

For the first star you can move the whole the mount (if you are so far off the screws aren't enough) and the screws. After that only use the hand control.

There is a polar assist in the align menu (assuming a recent enough set of firmware) and you use the screws to make that adjustment. Then redo the alignment stars with the hand control.

[Gem (Grant)]

Originally Posted by mithrandir

For the first star you can move the whole the mount (if you are so far off the screws aren't enough) and the screws. After that only use the hand control.

Not sure if you are giving the right advice for a CGEM.

[Poita (Peter)]

I found using the shadow method to align the scope during the middle of the day the best way to start.