CELESTRON ADVANCED VX MOUNT

[gonzostar]

HI

I have a celestron advaned vx mount. I do the 2 star polar allignment, with then 2 calibration stars (is that enough?) After that i do polar align mount. Then i get confused. Do i then have to switch the mount of and re align the alignment. Or could i do the align mount first using the handset? and do the alignment stars. I can get the alignment to within 10" in RA and better within dec.

thanks 

Dean

[Dr_Ju_ju]

Hi Dean,

Always do the polar alignment first, then other alignment steps. I roughly align using the polar scope & then drift align using align-master...

[Scorpius]

HI

I have a celestron advaned vx mount. I do the 2 star polar allignment, with then 2 calibration stars (is that enough?) After that i do polar align mount. Then i get confused. Do i then have to switch the mount of and re align the alignment. Or could i do the align mount first using the handset? and do the alignment stars. I can get the alignment to within 10" in RA and better within dec.

thanks 

Dean

If you use the handset's PA routine it must be done after you star align and yes it's a good idea to redo the star alignment once an All Star Polar Alignment has been completed. I used to just switch off the mount and do a second star alignment but you can also use the handset to change (replace) your calibration stars without powering down the mount. All this is described in the manual under the section on PA.

I don't go through all that anymore since I purchased Celestron's polar alignment scope. It's a fairly inexpensive device but somewhat challanging to adjust initially however, once it's set up PA is a straight forward process and can be done without powering up the mount or star aligning first. The catch is you must be able to see Polaris in order to use a polar scope. No matter which method you choose, you can get even closer to the NCP by using an inexpensive program called Align Master but then you may still need to go back and redo your star alignment for really accurate PA as well as accurate gotos. Of course drift alignment is the most accurate way to PA but I've not tried that method yet so can't advise.

Regarding star alignment, I always use two star align with 4 calibration stars. The AVX is a good entry level GEM mount however, you should plan on adding autoguiding before attempting any serious long exposure astrophotography.

Hope this helps & clear skies...

[Scorpius]

Quick follow-up, you said you do a 2 star polar align with 2 calibration stars but there's no such thing on the AVX. What I believe you're referring to is star alignment since the handset's PA routine doesn't involve calibration stars. What you're doing with calibration stars is refining your star alignment (gotos) while PA is strictly to get the scope pointing as close as possible to the NCP allowing the mount to track in RA only thereby minimizing field rotation...

But ultimately, long exposures without star trailing will be impossible if you don't add autoguiding...

[PeterCPC]

Just a point to note. After you have done the ASPA and looked at the error, don't believe it! You need to do another realign before you can believe the error quoted. I do 2 iterations of ASPA to get a good PA.

Peter

[Scorpius]

Hi Dean,

Always do the polar alignment first, then other alignment steps. I roughly align using the polar scope & then drift align using align-master...

Hi Julian,

Wasn't aware you can drift align using align master. What does it involve and how long does it usually take?

I'm still so slow getting setup and imaging, I' ve been reluctant to give it go...

Regards,

Paul