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jam1e1

eq6 pro and 3 star alignment

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Hi

I use eq6 sometimes from back garden hence limited views and stars to choose from, hence limited to choices of stars to align to.

I polar aligned mount to good enough accuracy, when goto 3 star alignment the first star is way off e.g. by about 3-4 full moon widths, then 2nd and 3rd stars are more or less ok and accurate?

Secondly, as cannot often choose first star that comes up, have to scroll across to others, when aligned a message sometimes appears "alignment may be poor" or "alignment failed" and have to start again?!

any advice? use handset with latest software

thanks

Edited by jam1e1
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If my first alignment star is out and I know the mount's polar aligned ok - then I just loosen the clutches and move the ota to point accurately at the object. Then lock the clutches again. It kinda cons the electronics into thinking it actually took the ota to the right position. Then everythings fine on second and third objects.

This is fine for observing - but imaging demands much higher levels of accuracy. :)

Edited by brantuk

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Check your home position. Poor home position will cause first star to be off. You may also want to check for any cone error.

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For some reason I do better with 2 star alignment than 3? Several times the hand box has told me alignment failed with 3 star. The first star is 'normally' way out but get better with the second, strange me thinks.

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Yeah, I often find the first star is off. If the telescope was bang on with the first star that you chose to use as an alignment star, then there'd be no point in doing the alignment process, would there :)

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After six years with my Atlas, I can say that some of us have had the experience of failed three star alignments. There seem to be one main cause, and possibly a second issue.

SynScan three star alignments have a difference that many of us don't think about when aligning. The third star is not a refinement of the alignment as in an additional point of alignment. It is intended to correct for cone error. If you do not have cone error in your setup, then SynScan tries to correct something that is not there, and it plays havoc with the result. So, unless your mount and OTA have a verified cone error issue (check the user manual for how to investigate), then I would recommend staying away from 3-Star.

Another quirk in this system is sensitivity to precision of alignment. I finally had to go to a reticle eyepiece to get as perfect as possible. If your eye and nose have the right configuration, you can introduce some parallax in the process and when you cross the meridian, you can double the warped sky in SynScan's mind. Throw in a third star, and the sky surprisingly becomes a carnival mirror to SynScan. I've had quite a few different systems over the years, and this one seems to be the most flaky with regard to small defects in process causing bad results. Most times, it is quite a good performer but then there are those nights that cause one to go bald. Be very, very careful with the setup of Home position and leveling, and it pays you back. Since a good polar alignment actually fixes one of the coordinate axes, I've had many nights where, with a good setup, I've only needed a 1-star alignment to get very good gotos. Even when a 3-star fails alignment.

Good luck; it can be like picking up mercury with chopsticks to make it work, on occasion.

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Thanks for that Skylook, it explains a lot! I sometimes get 'Poor Alignment' on a 3 star set up then do a 2 star setup and it works a treat!!

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thanks for responses - interesting reading, my experience is normally if can see and use the initial stars it selects your ok, if deviate issues seem to arise. Either way will try the above with 2 star alignment

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It's not necessarily the telescope!

I brought my HEQ5 mount indoors for testing and went through the 3-star alignment procedure in the daylight by just accepting the position the mount went to for each star (i.e. I made no attempt to align on anything) . Guess what - "alignment may be poor" came up! So there is a software issue somewhere in the Synscan.

NigelM

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It's not necessarily the telescope!

I brought my HEQ5 mount indoors for testing and went through the 3-star alignment procedure in the daylight by just accepting the position the mount went to for each star (i.e. I made no attempt to align on anything) . Guess what - "alignment may be poor" came up! So there is a software issue somewhere in the Synscan.

NigelM

Yeah, I strongly suspect a bug or too as well! :). Can be very frustrating though! For a few months now I have been using EQMod so obviously I don't get either the "alignment may be poor" or "alignment failed" Synscan error messages. So I am a happier bunny at least!

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