Live Stack photometry

[AMIF]

Photometric image of Z UMi, got with SC Live Stacking (60x5s without guiding).
Dark-flat calibration is fully satisfied, short track of hot pixel does not prevent measurements.

[AMIF]

UX UMa light curve got with SC calibration and stacking of short exposure images.
Regretfully, plate solving is long deal due to manual uploading of each stacked image to nova.astrometry.net for solving and downloading.
Photometry by AAVSO's VPhot.

[Jean-Francois]

Hello AMIF,

Nice light curve.

Which information do you need from the nova.astrometry plate solve ?
And which accuracy ?

The SharpSolve tool (integrated plate solve of SharpCap) is very quick and it found every time.
The focal does not be known precisely (or at all). That is a great, great improvement compared to other plate solve (I hate the integrate plate solve on Prism software ... if the focal is not set at 1 or 2 %, then it does not found).

Concerning the accuracy of SharpSolve ... it is build for quick centring of the telescope/mount.
It has no sub-arcsecond accuracy as other plate solve that performs a full astrometry fit of the image.

Regards,
Jean-Francois

[AMIF]

Thank you, Jean-Francois! Astrometry.net returns FITSes, suitable for VPhot processing - I do not know more, sorry

All my attempts to solve plates with Astap or SharpCap were unsuccessful due to comparely small field (a bit of less 30x20 min). SC tried to solve some images but shown other size of image, and in any case I did find way for solved FITS saving.

So fast plate solving for me now is limitation factor for long serias (and polar alignment, of course - I use old black HEQ-5 without GOTO and guiding ).

[Jean-Francois]

Hello AMIF,

Yes, ~ 30x20 arcmin is maybe too small and it could be at the limit of SharpSolve.

Do you want to perform the plate solve on each image ? ... for centring one image to the other ?
Or it is "only" one plate solve before the sequence for centring the first image ?

I guess that the photometry software should centre one image to the other.
The question will be to find the right target (and comparison stars) on the images.

HEQ-5 without GOTO and guiding is not the best.
I have a GOTO mount/telescope for more than 20 years ... it simplify a lot of work.
For guiding ... you can find different small guiding scope sometimes as bundle with a camera.

Regards,
Jean-Francois

[AMIF]

Well, SharpCap live stacking photometry works excellent - in any case, in cold season, when sensor temperature does not increase dramatically during long serias. Probably, in Summer short pauses for darks will be needed. Time will show.

The problem with plate solving is not so hard as I thought due to VPhot phenomenal possibilities