Use of iOptron iPolar Electronic Polarscope with Adapter (3339-AVX)

[TheAstrophotographer]

Robin,

I just got the Celestron AVX Mount and am looking at getting a polarscope for it. Initially I was looking at the QHY Polemaster; however, I am now getting the iOptron iPolar Electronic Polarscope with Adapter (3339-AVX).

The unit seems to allow for polar alignment at the same level and with the anticipated 2-3 platesolve and syncing that I will be doing after any polar alignment, I am hope to get close to less than 30-arc second of error so that I can image M31 at about 3-minute exposures for 40-50 subs.

I know for a fact that the QHT Polemaster can be used with SharpCap Pro for the polar alignment under tools.

However, I am wondering if the iOptron iPolar Electronic Polarscope with Adapter (3339-AVX) can also be used with SharpCap Pro polar alignment tools?

Thanks,

Edmund

[admin]

Hi Edmund,

I can't be 100% sure as I haven't tested that model, but the older iOptron iPolar does work in SharpCap and can be used with the polar alignment tools, so I think it is fairly likely that the model you are getting will work.

The iPolar showed up as a DirectShow (webcam) camera, and there were a couple of quirks - it needed to be run at a particular resolution and didn't work properly at other resolutions that it claimed to offer and the 'Brightness' had to be set to minimum to get a good image. SharpCap knows about these and will set up an iPolar automatically, but you might need to experiment with the newer device a bit if it has similar quirks.

cheers,

Robin

[TheAstrophotographer]

Robin,

Appreciate that very much. We will see! Would you recommend doing the polar alignment using the native iPolar software or would I better off using the SharpCap Pro polar alignment tools? Just wondering if anything is gained by using SharpCap versus native software?

Thanks,

Edmund

[admin]

Hi Edmund,

I hear a lot of people prefer SharpCap to the iPolar or Polemaster software, but maybe I just get to hear more about those sort of results than ones where people prefer the software from the manufacturer... If you are already familiar with polar alignment in SharpCap then I would definitely try that first as if the camera works you will be ready to go without needing to learn any new software.

cheers,

Robin

[TheAstrophotographer]

Robin,

Appreciate that - I like keeping everything in one place so if the iPolar polarscope operates under SharpCap Pro, I will use it for polar alignment.

I will also continue to use Celestron Unified ASCOM Driver to be able to follow-up with PlateSolve and Sync with SharpSolve to improve the alignment and reduce the GOTO error to less than 30-arc seconds.

Then likely will use my ZWO ASI220mm-mini for pulse guiding the mount using PHD2.

Thanks,

Edmund

[TheAstrophotographer]

Robin,

I just attached my iPolar camera and it connects no problem so hopefully it will work. It seems, I think if my reading is correct, the iPolar functions as a USB 2.0 UVC camera in SharpCap with no additional drivers needed, it seems to has a ~13 degree FOV and ~31.1 arcseconds/ pixel scale which should be ideal for pole-area plate-solving but requiring higher gain/exposure in my Bortle 5-6 to detect 15+ stars reliably.

My question now is SharpCap's Polar Alignment tool (Tools > Polar Alignment) would you happen to know the plate-solving arcminute accuracy used so that I can confirm it against my Celestron AVX tracking?

Thanks,

Edmund

[admin]

Hi,

I don't actually have a figure for that accuracy, but I would suspect it is in the 'small number of arcseconds' range. My typical polar alignment setup is a 200mm focal length guide scope + guide cam, which is about 4 arcsec per pixel, and the results move around by a pixel or two from frame to frame (mostly as a result of seeing changes shifting stars around slightly).

cheers,

Robin

[TheAstrophotographer]

Robin,

Is your guidescope on top of your OTA for polar alignment on SharpCap Pro?

Thanks,

Edmund

[admin]

Hi Edmund,

yes, basically (actually, I have 3 telescopes side-by-side mounted, and the guide scope is on top of one of those). There is no problem with an offset between the main telescope axis and the guide scope axis (after all, you are looking at things light years away, so 30cm to one side makes no difference). There is also no requirements for the two to be precisely aligned for accuracy, but within a degree or two is best for ease of use. The thing you do have to be careful about for this type of polar alignment is to ensure that the scope you are using is firmly attached (no flex in the way it is mounted to the mount) and that the cable to the camera is restrained so that the weight of the cable isn't pulling on the back of the camera.

cheers,

Robin