Some Observations using Live Stacking

[DiligentSkies]

Hello Dr Glover,

Have a couple of clarity questions about subs fits files saved when live stacking.


Am I correct that if you have subtract darks and apply flats set in preprocessing then the individual subs are saved with these masters applied to the save data?
I am asking this because...
I am having replay issues with folder monitoring reprocessing of my subs into just another live stack outcome.
I don't seem to be able to produce the same quality of results as of the live final stacked results when I replay my subs in folder monitor.
I am thinking that I am subtracting and applying twice these mastered calibration frames.

With regards to above preprocessing concerns, " Does SharpCap use internally the results of sensor analysis to optimize its stacking and stretching for the giving gain and exposure that I am imaging with?"
Could this be the source of replay results in folder monitor?
That is these data points for sensor analysis optimizations to kick-in are not being read from FITS Header on folder monitoring replay.

Second, does fiddling around with either the display histogram stretch controls or the live stack histogram stretch controls while the stacked image builds.
- Does this alter the underlying next saved subs data?
- Does the above change/reset the average measured reference to the on-going stack?
(That initial frame count setting in the Stacking Tab)
- Does changing the Enhancement-> Noise Reduction/Sharpening settings affect the next saved sub or the on-going live stack in anyway?

-mark

[admin]

Hi Mark,

when you are live stacking and choosing to save the raw frames, those frames are saved exactly as they come off the camera, with no dark or flat frames applied - this allows you to perform a full reprocess later either using the same dark/flat used for live stacking or with alternative ones (perhaps captured after the live stacking run). If you use the folder monitor camera to reprocess then you need to select the dark/flat frames in SharpCap when using that camera to avoid stacking unprocessed frames.

Note that if you use normal capture functions in SharpCap and use dark/flat then the saved frames *DO* have them applied. It is only live stacking raw that saves with no dark/flat applied.

SharpCap doesn't use the sensor data for stretching or live stacking purposes - the auto stretching performed when live stacking is purely based on the brightness distribution of the stack.

All the adjustments in live stacking like colour balance, histogram stretch, sharpening, noise reduction, etc are applied on the fly as the current stack image is being made ready to display - they do not affect the data *in* the stack at all, just the rendition that you see of it on screen. They also do not affect the saved raw frames from the stack.

Hopefully this info at least helps you rule out some possibilities for the different results.

cheers,

Robin

[DiligentSkies]

Robin,

Thank you for the response.
Your reply helped clarify some of the ambiguity.
Most of the issues I was having stem from FITS Header Data inconsistencies.
Example, one night I called my target SG, and the Next Night I called it Seagull.
Another take away is, FITS Header values are case sensitive.
Example: Object values such of SeaGull and Seagull are parsed as two distinct values.

Where there is all headed is many PixInsight processes and scripts read this info extensively.
So that is where my problems resided.
I have since stream-lined these end user inconsistencies.

Thank you again, your reply helped big time in sorting things out.

-mark