2-3 star aligment? Whats that good for?

Hi!

Just bought a Skywatcher 150/750 with an EQ5 mount,

but im thinking about eitherway upgrade my current mount with the SynScan Pro GOTO Upgrade Kit for EQ5 & EQ6 or maybe even buy a new gotomount.

One thing I dont get about the synScan is that why it requieres 2 or even 3 star aligment? Im actually used to get polaralignment and thats it for me xD

Or polaralignment isnt required if I go for the 2 or 3 star method?

Im kinda new with this so any tips will be extremly helpfull

felipeburdiles said:

Hi!

Just bought a Skywatcher 150/750 with an EQ5 mount,

but im thinking about either way upgrade my current mount with the SynScan Pro GOTO Upgrade Kit for EQ5 & EQ6 or maybe even buy a new gotomount.

One thing I dont get about the synScan is that why it requires 2 or even 3 star aligment? Im actually used to get polaralignment and that's it for me xD

Or polaralignment isnt required if I go for the 2 or 3 star method?

I'm kinda new with this so any tips will be extremely helpful

Click to expand...

First tip:

Post this in the Astrophotography forum. At least I think that's the right forum.

The polar alignment, having the mount pointed at Polaris, is most important. The two-object alignment increases the tracking accuracy, and additional objects for alignment located in different parts of the sky further increase the tracking accuracy.

Are you trying to use your setup photographically or just to look through the thing?

Commercial mounts (like the EQ5, or "Sirius" in the Orion Telescopes world) is a really nice "budget" mount. I have the bigger brother, the "Atlas" or EQ6.

Basically, the 2- or 3- star alignment are fine if visual is your stopping point. But if you want to use the mount photographically, you need to polar align the mount. If you're using software for polar alignment, what many packages do is take a series of images to see where the scope IS pointed compared to where the mount THINKS it's pointed, compare those data to your specific location via GPS and time, and then calculate a polar alignment solution for you.

But - the more recent mounts from Celestron, SkyWatcher, and Orion (as well as others) can also do this without additional software.

I forget what Orion calls theirs, but the basic idea is you FIRST do a good 3-star alignment, then there is an additional routine where the mount will ask you to slew to a star near the celestial equator. The initial slew is based on your 3-star alignment, but then it will do a second slew to where the star WOULD be if you were correctly polar aligned. The difference in positions of the same star is your polar alignment error.

The routine then will have you manually adjust the altitude and azimuth to put the star back in the center of the field of view, and you will have a "good" polar alignment.

If you repeat this once or twice, it will improve your alignment.

If you're using a separate computer to help you with your alignment, then you're a right a 2- or 3- star alignment is not necessary. But if you're going without a computer then these built-in routines are pretty helpful.

--
Dan
My Flickr: https://www.flickr.com/photos/87860695@N03/