M 83 test

[poppasmurf]

Been testing the new focusser and also Prism software. This is 24 5 min Lum exposures all taken with Prism10 including guiding.

For some strange reason when I calibrate the images they become unusable like they are straight from the camera with no signal. So I stacked and post processed them in PI without calibrating and here is the result. I will have to investigate further to find out whats going on, most likely user error :question:.

Shane

[alpal]

Hi Shane,
I'd love to help you but I know nothing about the software you're
using & you have provided almost no details:

Are they FITS files?
Did you take time to focus correctly?
Did you try Deep Sky Stacker?


What does unusable mean?
How can there be no signal when the picture you posted has signal?
Nothing makes sense.

cheers
Allan

[poppasmurf]

Hi Allan, thanks for the reply, the files are FITS files and captured using Prism10. Focus was spot on, I used the autofocus routine in Prism which takes a series of shots intra and extra focus and measures HFD and sets focus position to best HFD position, not yet set up temp compensation.
I don't have DSS to try but up till now have had no problem with PixInsight.
By unuseable I mean the files, when taken into PI, are fine as shown by the above image, but if I callabrate the images before any other processing then they go dark with a few bright stars showing, and STF function will not change them to be able to see what signal is there. This issue makes them unuseable as STF is needed to see what happens during other processing steps before HT is done.

Any tips greatly appreciated.

I quite like Prism 10 for telescope, focus, guiding, imager, plate solving and observatory control (when I can eventually add a dome or motor for ror), I don't plan on using the processing capabilities as I like PI for that.
Using a single software package greatly simplifies things in my opinion, as opposed to using multiple packages theat need to play nice together.

Regards Shane

[RickS]

Hi Shane,

The FITS standard doesn't specify the range of values that is valid in floating point data, so integer and unsigned FITS files are compatible between different applications but floating point FITS files may not be. It is likely that the calibrated files out of PRISM are floating point and use a different range of values to PixInsight (which uses 0..1).

If you save the calibrated images from PRISM as 32-bit unsigned then that will probably work. Alternatively, you can tweak the floating point data range that PI expects on input in the Format Explorer.

Cheers,
Rick.

[alpal]

Hi Shane,
OK - I have a different method.
I stack with DSS - output as 32 bit FITS files and I think it's as integers not floating point.
I then stretch them with NASA FITS Liberator & save them as 16 bit TIFFS
so that they can be processed in Photoshop and Fitswork4.
There is probably an advantage in keeping the data in 32 bit format using PI but
as the KAF8300 camera I use has only 16 bits then 32 bits is probably going overboard
for negligible gain.

I advise you to try that method as it's actually quite easy -
if you have Photoshop open then NASA FITS Liberator will
put each LRGB file straight on to the screen ready to process.
NASA FITS Liberator also gives you many different mathematical stretching algorithms.
I suppose PI does the same?

cheers
Allan

[poppasmurf]

Thanks for the replies gentlemen, much appreciated.

Rick: I'll have to check what Prism saves its files as(flotingpoint,signed or unsigned integer).

Allan: I gave up photoshop a long time ago, I could never get the hang of it. Hence I use PixInsight for all my pre/post processing.

Shane

[alpal]

Hi Shane,
Louie made some great and easy to follow videos for Photoshop here:


https://www.youtube.com/channel/UCJ5b6pFHBGe66vsuSaXb-0A