Want to buy gear, however, can't see Polaris.

[buggz]

Hello,

I've been wanting to get into this for a while, however, we can't see Polaris due to trees.

Can the new GEMS use other star patterns to align the mount?

I'd love to get an Ioptron Skyguider Pro for my mirrorless.

 

[buggz]

Okay, this looks good:

Should You Upgrade your iOptron SkyGuider Pro with iPolar?

I had mixed feelings about about disrupting this setup with an upgraded electronic polarscope - but I think I can live with this one. My results using a DSLR and telescope:

astrobackyard.com

 

[Rutgerbus]

Okay, this looks good:

https://astrobackyard.com/ioptron-ipolar-skyguider-pro/

Yes, iOptron has the iPolar feauture build into their newer mounts like the CEM40. With the iPolar you don't need to have a clear view on Polaris. It can also use other stars in the sky to do a proper alignment. I think you can buy the iPolar technology also for other mounts that don't have iPolar yet...

PS: I love my CEM25P....lightweight, acurate and with the ASIAir and dedicated Astrocamera's it's not even a problem to get pinpoint stars after one single 30min exposure.

 

[Rick_in_madison]

In that article, note that they quote a FOV for the iPolar of 13º. The device should be aligned with the RA axis of the mount, which in turn has to point at the celestial pole, so although you don't have to be able to see Polaris, it's not as if you can point the iPolar in some other direction and expect to get a good alignment.

If I'm wrong there, please pile on. But I'm unaware of any other consumer tech that does that. Usually the Pole has to be within the FOV of the camera, even if Polaris itself is not visible.

As for CEM25Ps getting 30 minute pinpoint stars...unguided? Really? 'Cause mine struggles with more than a minute.

 

[Alen K]

Okay, this looks good:

https://astrobackyard.com/ioptron-ipolar-skyguider-pro/

Yes, iOptron has the iPolar feauture build into their newer mounts like the CEM40. With the iPolar you don't need to have a clear view on Polaris. It can also use other stars in the sky to do a proper alignment. I think you can buy the iPolar technology also for other mounts that don't have iPolar yet...

Some other mounts have a similar feature. Celestron's AVX can do it using a feature called All-Star Polar Alignment, although maybe not as well. (The AVX probably doesn't do anything as well as an iOptron CEM mount.) Heck, my ancient Vixen GP-DX with SkySensor 2000 Goto can do it (very well), and Vixen doesn't even give the capability a name.

But did you know you can polar align very accurately without seeing Polaris with almost any equatorial mount, even one lacking Goto? All the mount needs is a motorized RA axis. The procedure is called drift alignment. I used to do it all the time before I got the GP-DX. What's that I hear from someone? It takes too long? Not if you involve your camera in the process. See this post.

 

[dswtan]

Another common option is the one I use on my Celestron CGX where I can't see Polaris, but it's totally mount-independent -- SharpCap (Pro version only, small cost).
https://www.sharpcap.co.uk/sharpcap/sharpcap-pro/sharpcappro

Celestron's All-Star Polar Alignment (ASPA) might work for me too, but I have so many obstructions and SharpCap Pro "just works". Super quick and simple!

 

[Rick_in_madison]

As for CEM25Ps getting 30 minute pinpoint stars...unguided? Really? 'Cause mine struggles with more than a minute.

Oh. Duh. Didn't note who was talking there. Sorry Rutger, I know better than to doubt you!

WRT alignment procedures with Polaris invisible: I know that iOptron has a procedure in which you do some alignment on some stars, then it slews the mount to a target and you use the altitude and azimuth adjustment to eliminate half of the distance to centering it. Then you iterate over a set of targets until they're all within your tolerance. iOptron calls it "Polar Iterate Align" in their manual. I've never used it:

This alignment method allows you to polar align the mount even if you cannot view the Celestial Pole. Press the MENU => “Alignment” => “Polar Iterate Align”. The hand controller (HC) will display a list of bright alignment stars near the meridian as Alignment Star A. Follow the HC instructions to move Alignment Star A to the center of the eyepiece using a combination of the Latitude Adjustment Knob and the “◄” and “►” buttons. Press ENTER to confirm the settings. Next, select a bright star that is close to the horizon as Alignment Star B. Center it using the Azimuth Adjustment Knobs and the “◄” and “►” buttons (the “▲” and “▼” buttons will not function). Press ENTER to confirm the settings.

The telescope will now slew back to Alignment Star A to repeat the above steps. The iteration can be stopped when it is determined that the alignment error has been minimized. Press the BACK button to exit the alignment procedure.

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