Having trouble making accurate alignments?

[ILoveKnowledge (Sassan)]

Hi all! I have a Celestron Nexstar 8SE telescope and I even bought the GPS unit for it! For some reason with deep space objects away from the immediate planets, I have trouble accurately centering the three stars during the alignment procedure and while near space objects such as the planets work well with the "GoTo" hand controller, the deep space objects always seem to be slightly off. Do you have any tips or hints on what I should do? Also, if the objects are slightly off, what is the best way to find the objects? Use a star map? I was hoping that with my GPS skysync unit my alignments would be completely on target. It is a little frustrating. All tips and hints would be highly appreciated.

Thanks in advance!

[silv (Annette)]

Hey Sassan,

here is what I learned last week:

"slightly off"
can mean too far left/right or too far up/down.

too far left or right ---> amend your SCP alignment. Because this means, the mount looks too far east or west.

or
too far up ---> the latitude in the mount itself is set too high ( the tube points above the actual location of the star because it assumes standing further south from the equator)

or
too low (the tube points below the actual position of the star because it assumes it is standing closer to the equator.)

(Don't overly trust the latitude wheel in the mount head. They're not accurate.)

or
the mount might not be leveled properly. Don't trust the bubble level in the mount head. Use a real builders bubble level.

Silv

[Allan_L (Allan)]

Originally Posted by ILoveKnowledge

Hi all! I have a Celestron Nexstar 8SE telescope and I even bought the GPS unit for it! For some reason with deep space objects away from the immediate planets, I have trouble accurately centering the three stars during the alignment procedure and while near space objects such as the planets work well with the "GoTo" hand controller, the deep space objects always seem to be slightly off. Do you have any tips or hints on what I should do? Also, if the objects are slightly off, what is the best way to find the objects? Use a star map? I was hoping that with my GPS skysync unit my alignments would be completely on target. It is a little frustrating. All tips and hints would be highly appreciated.

Thanks in advance!

Hi Sassan,
Welcome to IIS
and Greetings from Down Under

With the Nexstar 8SE, a couple of things improved alignments for me.
1. Try to make sure the tripod base is level before attaching the mount.
2. Don't use planets for the auto align process.
3. Always approach your alignment star from the same direction as the scope normally slews.
4. After successful alignment, always check the accuracy by returning to the original alignment stars via GoTo. If these are off, use the re-alignment function to adjust.
5. Perhaps the most important (and hardest to check and adjust) is balance of the OTA. There is very little adjustment (ability to slide the OTA up or back the mounting clamp), but if you use heavy eyepieces or diagonal or other equipment, it can significantly effect your goto accuracy. This is usually characterised by the OTA pointing lower than the target object. This may be obvious from the results of 4. above.
To correct this, you may have to fashion a way to add weight to the top end of the OTA.

Hope this helps some.
Allan