Polar Alignment

[triumph900tbird]

I am aware of the need to polar align a scope mount and I am reasonably aware of how to do it using the new firmware upgrade to the Celestron GoTo handpiece. Well to be honest the opportunities to practise have been few and far between this year, however.
I've been thinking. My telescopes CG-5 goto mount asks that the mount be set to the index marks prior to beginning the alignment process. After inputting all the necessary location and time data it will pick an alignment star. The mount will then move to the location where the star should be. The operator then moves the scope to the right RA and Dec using the handpiece to align the scope.
So, when it first starts the scope is working from the position that it is set to polar alignment. Correct?
If the above is true then when the scope goes to the first alignment star then you could use the Dec. and RA screws to align the scope to the star not the hand piece. It stands to reason that if you then turn the scope off and put it back on the index marks it should be on or very close to the SCP. Basic geometry really.
Starting the scope again and inputting the new time, pick a new alignment star and the scope will then move to the 1st alignment star and it should be really close.
The second one should be even closer. At the end of all this you should be near polar aligned. Well close enough for visual work.
Or am I missing something?

Brian

[mithrandir (Andrew)]

Your idea is reasonable. The way I'd get the first alignment star on my CG5 was to level the mount (do not believe the built in bubble - check it with a real level), set the axes to the index marks, power up, set the clock (I'm lazy, I have the GPS accessory), and go to an alignment star.

Without touching the hand control use the RA and Dec alignments to centre the star. Use the HC to sync to the current star.

Go to another star in the align list on the same side of the meridian - at least an hour different in RA. Use the HC to centre and additional align. Optionally repeat. Additional align another star on the other side of the meridian.

Now use the polar alignment assistant from the menus, follow the instructions and you should be well enough aligned for visual purposes.

Repeat the sync, additional align, polar adjustment sequence if you want to try photography. I was not happy with CG5+C8 for photos of DSOs but it was OK for < 30 sec exposures.

Andrew