5 replies to this topic

[aroughroad]

Hi all,

I’m quite familiar with calibration of deep sky objects, but I now have a ton of data from my first solar eclipse and would to understand best practices for calibration of these light frames. I typically do all calibration in PI via WBPP but am not sure if that’s advisable for these data.

For this eclipse, I was able to capture:
- 32 diamond ring frames leading up to C2
- 14 Bailey’s beads frames leading up to C2
- 12 frames of the chromosphere immediately following C2
- 12 frames of the prominences immediately following C2
- 6 HDR sequences of totality each consisting of 12 shots with shutter speeds from 1/500 to 4” separated by a full stop
- 12 frames of the prominences leading up to C3
- 12 frames of the chromosphere leading up to C3
- 14 Bailey’s beads frames immediately following C3
- 32 Diamond ring images following C3

I’ve taken bias, darks, and flats. So, my questions:

1. Should I use WBPP in PI the same way I typically do to calibrate each individual light frame from my list above?

2. The only images I’ll be stacking are the HDR totality sequences, so what is the preferred process? Calibrate and then integrate each set of frames by exposure time (i.e., calibrate/integrate the 6 1/500s frames, then the 1/125s frames, etc.)?

3. What is the best way to integrate the totality sequence frames? I have read that PI cannot align the frames since the moon is constantly moving and a 1/60s shot taken early in totality will not align with a 1/60s shot taken near the end of totality.

The few totality processing tutorials I’ve seen online begin with a series of calibrated and stacked frames at different shutter speeds, but I’m trying to figure out how to get to that first step of having those stacked images to begin with.

Any suggestions are very welcome!

[Daniel Dance]

I'm in the same boat as you.

First of all, you can probably throw your dark frames and bias away.  Not needed.   Unless you're using a guidescope and precisly tracking the Sun, then dark frames aren't going to help as you're essential dithering with the unguided tracking of the Sun.  Bias frames - well . . . i haven't done bias frames in 10 years on anything.

 

But flats are very important.

 

For alignment, manual alignment in photoshop is the way to go.  And you'll be aligning to brighter stars or prominences, not the Moon disk as you want to align the corona.

[aroughroad]

I was tracking with an equatorial mount and taking up to 6s exposures, so I'm inclined to suspect there is some thermal noise (hence the need for darks).  Plus, Druckmuller insists all three be done and I dare not question the master...

 

http://www.zam.fme.v...nstructions.pdf

 

Are you using only one bracket or are you stacking more than one?

[R Botero]

What camera did you use?  If a modern CMOS camera, no need for bias or darks.  Flats should work on their own.  I used PIPP to sort through my SER videos.  It allows to incorporate calibration frames (as single stacked shots or as SER videos themselves).   It will use all bias, darks and flats if you have them.

 

I could not really integrate my SER frames as clouds were too much.   If you had good conditions, you can go from PIPP to Autostakkert for stacking.  These are all freeware used by planetary/solar/lunar imagers.

 

Roberto

[aroughroad]

What camera did you use?  If a modern CMOS camera, no need for bias or darks.  Flats should work on their own.  I used PIPP to sort through my SER videos.  It allows to incorporate calibration frames (as single stacked shots or as SER videos themselves).   It will use all bias, darks and flats if you have them.

 

I could not really integrate my SER frames as clouds were too much.   If you had good conditions, you can go from PIPP to Autostakkert for stacking.  These are all freeware used by planetary/solar/lunar imagers.

 

Roberto

Thanks Roberto.  I used a Canon Eos R5 (mirrorless).  I think I will try calibrating in PI per my usual routine and then stack the brackets in Photoshop.  Hope you had some nice visuals even if the clouds posed imaging problems.  

[R Botero]

AutoStakkert and PIPP will accept your list of files from the Canon as well as calibration frames (masters or in the case of PIPP from video files also).   I would suggest using AutoStakkert for stacking your shots.  It's much better at sorting by quality and stacking using methods not available to PixInsight (developed for planetary imaging).  It's freeware.  https://www.autostak...om/wp/download/

 

Good luck either way!

 

My shots from Mazatlan are here:  https://www.astrobin.com/0ef83r/F/

 

Roberto