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View Full Version here: : City AP: Jewelbox 3hrs using DSLR on GSO 10"


Phisci
25-07-2018, 04:36 PM
10" F5 Newtonian on EQ6 mount, guided via PHD2;

3 hour stack calibrated for bias and flats but not darks (darks seem to introduce a fair amount of noise).

Joburg redzone and halfmoon; ISO200 with 1min subs using Samsung NX500

cometcatcher
26-07-2018, 10:03 AM
Beautiful rendition and framing Ryan. One would never know it was taken in LP skies.

Premordial
26-07-2018, 11:55 AM
Nice shot. The Jewel Box never gets old.

Phisci
26-07-2018, 05:28 PM
Thank's for those comments- still scraping the surface on Pixinsight-my images tend to have a whitish overlay-could this be due to missing something in my processing?

I typically do the following:

Calibrate with flats and bias; darks tend to add noise it seems in my case
Debayer
Register
Integrate

Crop
ABE and DBE
SCNR for green
Background Neutral
Photometric Colour Calib
Masked Stretch or Archsinh or both
Tweak with Histogram or Curves Transformation

Any other tools I should consider using for DSLR in LP environment?

RickS
30-07-2018, 08:14 AM
A nice Jewel Box, Ryan.

The "whitish overlay" is probably a result of too much empty space at the left hand side of the histogram. Use HistogramTransformation and move the black point to the right until just before you start clipping the data.

You seem to have the basics of a decent workflow. Do you do any masking when tweaking curves? That's helpful if you want to boost saturation, etc.

Cheers,
Rick.

Phisci
30-07-2018, 06:15 PM
Thanks for the suggestion Rick, I have tried masked stretch to good effect but will start to explore use of masks more broadly.