Troubleshooting Polar Alignment

[HeavyT]

Thanks again Robin

[seeker372011]

Hi


I am based in Sydney Australia and tried to polar align with a Polemaster camera using SharpCap last night

unfortunately Sharpcap couldnt find more than 4 stars - found two then three and then four and then fell back to 2. I was pointed very close to sigma octans -could see it clearly in the snapshot.

I could see plenty of stars in the snapshot which I have uploaded to my flickr account temporarily

https://flic.kr/p/2iXM29F

so in effect I never got to even step 1 of the polar alignment routine

what am I doing wrong? Help would be most appreciated

many thanks in advance

Narayan

[admin]

Hi,

did you look at the hints on this page? https://www.sharpcap.co.uk/sharpcap/fea ... leshooting

Sounds like you need more exposure/gain to get more stars to show up.

cheers, Robin

[SteveInNZ]

It looks to me like your exposure is too long, making the background level too high.
My settings for a Polemaster in Auckland suburbs are Exp=150ms, Gain=70.

Steve.

[seeker372011]

Thanks I’ll try both suggestions !

[KiwiFPV]

Hi,

I have a question re PA and plate solving. I have tried now many times (with only once or twice succeeding a least going past the first recognition) to PA - plate solving within it just doesn't seem to work regradless what settings I change. Last night I decided to try and run plate Solving on its own (forgot that PA was still running). Plate solving worked perfectly fine - so I presumed the camera settings were ok too. Going back to PA I could not change the outcome (tried resetting all the values etc.). Is there something I am missing or doing wrong? Wouldnt cahgne to any other software btw...love all the aspects of it.

Cheers
Harry

[admin]

Hi Harry,

do you rememeber what the results of the 'standard' plate solve were? Were you within 5 or so degrees of the pole (from your username, I'm guessing it might be the south celestial pole...). The plate solving in PA has a smaller database limited to about 6-7 degrees from the pole at the most (this is for speed), so if you were further out than that, you have the reason for the failure.

If you were within 5 degrees of the pole, check the field of view of your setup is within the supported range (at least half a degree in each direction, ideally not more than about 3-4 degrees in each direction) and that the number of stars being detected is decent (20+).

If you are still stuck then the best thing to do is to simply press the 'Snapshot' button to save an image of the sky that you are trying to polar align on and share it here, then I can advise further.

cheers,

Robin

[KiwiFPV]

Thank you everyone for taking the time to reply. I finally managed to get the mount polar aligned - took screencaptures (thank you @admin) and uploaded them to astrometry for plate solving to have a visual in Worldtelescope where I am "at". Was waaayyy off teh SCP, RA scale on the side of the telescope is off by at least 4degrees. After a few more screencaptures and plate solvings and manually adjusting the mount I was finally within the range of the plate solving for PA in Sharpcap and after that it was a breeze - love the feature!!! Got to about 1degree (Good) in PA and after that the mount was just fantastic with tracking. Coming from Alt Az on Nexstar this was just amazing...20+s exposures with no trails on the stars. After quite a bit of frustration and nearly doubting teh purchase of the mount this has got the excitement back... and of course finally able to use Sharpcaps Polar Align feature was awesome too..soo easy once it is within the limits.

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[admin]

Hi,

good to hear that you got there in the end Interesting that the underlying problem could have been the altitidue scale on the side of the mount being mis-applied - fortunately if you leave that in place from now on at the right elevation, you shouldn't be bitten by the same issue again.

One other thing to note is that you can use 'Plate Solve Only' from the tools menu in place of uploading to astrometry - recent versions of SharpCap (last year or two) have a built in plate solving tool that should work for this sort of field of view, and with the 'plate solve only' option, it just displays the center co-ordinates in a notification.

clear skies,

Robin

[KiwiFPV]

Hi Robin,

thank you for such an awesome piece of work. Last night (clear skies and very nice temperatures of around 18degrees C with very low humidity and Bortle 4-5), polar alignment worked out very quickly (excellent results) and then I decied instead of the usual Synscan 2-star alignment to use Sharpcap and a PC to mount connection to use the internal Goto Catalog Target/Co-ordinates fucntionality and wow did that just change the whole game..lol...sooo easy to find targets...no guessing or fiddling with the controls etc...just tell it where to go and Sharpcap with plate solving etc does it all for you. Afer a lot of frustration with the Celestron Alt Az mount I have finally re-discovered the love (I always had it but it was taken over by frustration) for astrophotography. I am now already aiming at more tricky subjects and even if they dont turn out great to start with, at least now I know that my OTA is pointing at the right subject and the mount is keeping it where it should be...Thanks again for a great piece of software
Clear skies from Australia

Harry