Author Topic: Unable to get StarAlignment to work  (Read 977 times)

Offline rtemen

  • Member
  • *
  • Posts: 56
    • View Profile
Unable to get StarAlignment to work
« on: 2017 April 28 20:44:25 »
I have 10 lights of M104 and I have tried a dozen times or more to get them to star align.
I have tried many tweaks of various parameters, to no avail.
Would anyone be able/willing to look at the two sample files and let me know what I need to do to get them to align?

Here are the two files:

https://www.dropbox.com/s/ul248u2y9surrex/debayer_LIGHT_180s_800iso_00014.xisf?dl=0
https://www.dropbox.com/s/g0rk8lm13dm80k4/debayer_LIGHT_180s_800iso_00019.xisf?dl=0

Thanks,
Rich

Offline msmythers

  • PTeam Member
  • PixInsight Jedi
  • *****
  • Posts: 1176
    • View Profile
    • astrobin
Re: Unable to get StarAlignment to work
« Reply #1 on: 2017 April 28 22:10:34 »
Rich

I found this worked.


Mike

Offline rtemen

  • Member
  • *
  • Posts: 56
    • View Profile
Re: Unable to get StarAlignment to work
« Reply #2 on: 2017 April 29 05:45:41 »
Thank you much.
That did the trick.

Offline rtemen

  • Member
  • *
  • Posts: 56
    • View Profile
Re: Unable to get StarAlignment to work
« Reply #3 on: 2017 April 29 15:18:57 »
Hi, again.
Now that they all aligned, I stacked them.
The resulting file is quite disappointing.
I have been running several tests/experiments with this set of files.
What I seem to be seeing is that no matter if I stacked these shots with or without using flats, it results in this file which looks identical to me whether I used the flats or not.
Then, I followed several tutorials out there on the internet, and I cannot get rid of any of that rainy streaky looking stuff.
Would you (or anyone else that can see this file), have some time to analyze it with the pixinsight tools to let me know if there is something drastically wrong with the file so that I may learn what is happening?

Here is the link to the file.

https://www.dropbox.com/s/tqae9g53zwlveyj/M104_IntegrationNF.xisf?dl=0

Thanks to anyone who can look at it and coach me.

Rich

Online pfile

  • PTeam Member
  • PixInsight Jedi Grand Master
  • ********
  • Posts: 4479
    • View Profile
Re: Unable to get StarAlignment to work
« Reply #4 on: 2017 April 29 17:23:30 »
so here is how your situation happens:

1) unguided imaging, or guided imaging with differential flexure between the imaging camera and guide camera leads to a steady diagonal drift.
2) calibrating the lights with a dark, and scaling the dark, leads to undercorrected hot pixels. this is especially a problem with DSLRs because they are not cooled, so there are a lot of hot and warm pixels in the lights.
3) these undercorrected hot pixels are essentially too dim to exclude as outliers and reject them during integration
4) the hot pixels are left in the stack and show up as diagonal streaks

just about the only way to get rid of these is to either not scale the darks during calibration of the lights, or after calibrating the lights, try to use CosmeticCorrection to get rid of these pixels before registration and integration.

rob