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The obligatory "my first M42" image...

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For the first time in ages we have had clear skies when I have not been away, out, or needing to get up at 05:30 to go to work. So I took vicious opportunity to try to reacquaint myself with the telescope and try to remember which end you point at the stars. This is also the first time I have felt that I have done well enough to post in her with the big boys and girls, rather than in the beginners section.

I have managed to not blow out the core of the nebula. In fact I had another forty 30 second shots which PixInsight declared it did not need when building the HDR image. Given that they were quite noisy even after calibrating I made the decision to not include them. So here we have 17x120", 12x300" and 12x600" over three nights, each night had it's own set of flats.

All the processing was done in PixInsight (which I think has taken longer than the image acquisition).


Things I have learnt from this:

  • Guiding is hard. I managed to get PHD to have a RMS error of <2" most of the time, but every 10 minutes or so, the declination graph went 30"+ off the scale and took 10 seconds to come back, which ruined a number of shots.

  • Only having a dew heater tape on the imaging scope means that as the night goes on, the guide scope mists up and the S/N goes from 35 down to 3, and then it all goes wrong.

  • I am really glad I bought those Finnish cold weather boots

  • Removing the banding on images generated by my DSLR is hard, even with the scripts in PI.

  • I really enjoyed the whole process!

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Welcome to the imaging - Deep Sky section, prepare to spend much time in here! That's a lovely image to start with too.

It would be worth trying Noel's Actions and the remove bands action if you have photoshop, that should help with that problem. Not sure why the guiding is being so problematic, you should be able to get the system churning out consistent subs. Definitely a good option to fit a dew heater strap to the guide scope too.

It is most enjoyable when the weather permits and just frustrating when it never seems to look like clearing. Though I have to say that I quite enjoy the weather closing in after a few nights of clear skies - it gets tiring!

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Thats a great attempt at M42 with a DSLR. I'm just curious as to whether you convert to tiff before stacking or if you stack the raw files directly. The reason I ask is because I recently realised that by converting my lights and darks to tiff, beforehand, I somehow made banding worse. 

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Rico, all of the processing was done using 64 bit FITS files. PixInsight uses FITS thoughout.

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PixInsight is alien to me ... I use DSS with PS to do all my astro work. There just seems to be so much banding in your image, given the amount of data you have. Do you know if they're coming from a specific set of images you took. 

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Try processing with and without your calibration frames. I get the impression, that sometimes this can actually make the final image worse as well. 

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