DSS save as ? choice.

Questions and answers about processing in StarTools and how to accomplish certain tasks.

DSS save as ? choice.

Postby gramps » Sun Oct 01, 2017 9:29 pm

When I save the resulting image in DSS as a FITS file I have 3 choices,
16 bit/ch
32 bit (interger)
32 bit (rational)
Which is the correct one.
Thanks, Tim
Whose mom kidding, I don't see any electricity in there.
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Re: DSS save as ? choice.

Postby admin » Mon Oct 02, 2017 12:29 am

Hi Tim,

To make a long story short, 32-bit Integer FITS is the best choice here.
To make a long story long, 16-bit integer usually provides enough dynamic range but may fall short depending on how you stacked and how many subframes were stacked.
32-bit floating point is not a bad 2nd choice, however leaves room for encoding anomalies such as NaN ('not a number') and plus or minus infinity. For our type of instruments (e.g. CCD cameras with mostly linear response), floats also effectively only provides 24-bit dynamic range (with 8-bits allocated to the mantissa which stays the same for all values). Finally the StarTools engine uses integer fixed point math in a lot of places for optimisation purposes internally, so there is a float->int conversion happening anyway.

Love your profile pic / avatar by the way! :lol: I can't help but wanting to scream nooooooooo!
Ivo Jager
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Re: DSS save as ? choice.

Postby gramps » Mon Oct 02, 2017 1:00 am

Thank you sir, I'll stick with the first simple answer, the explanations make my head hurt. Belive it or not I did test my mothers theory about electricity back in 1944. I was too smart to use a knife, I use my fathers metal screw driver. The results were spectacular. That's probably why I'm a slow learner. :shock:
Tim

ps. I did purchase your program, just waiting for the numbers. :D
Whose mom kidding, I don't see any electricity in there.
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Re: DSS save as ? choice.

Postby gramps » Mon Oct 02, 2017 1:03 pm

I received the license file. It took several tries but with the better half's help I am now registered. Your message at the end says to "Read quick start tutorial".
Where would that be located because I'm going to need all the help I can get.
Thanks, Tim
Whose mom kidding, I don't see any electricity in there.
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Re: DSS save as ? choice.

Postby admin » Mon Oct 02, 2017 2:00 pm

Hi Tim,

You can find the quick start tutorial here;
http://www.startools.org/modules/introd ... uick-start

I can also heartily recommend this tutorial by user ecuador here on the forums;
http://astro.ecuadors.net/processing-a- ... startools/

And if all fails, share some of your data with us (through Dropbox, Google Drive, One Drive, etc.) and we can have a look and share our logs with you.
Ivo Jager
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