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Lunar, Celestron C8 + QHY5LII-M + IR Cut Filter

Posted: Thu May 16, 2019 8:53 pm
by turfpit
The following were captured 14th May 2019 through intermittent high cloud. The links are to the high res images. 80% waxing Moon.
All 1280x960, MONO8, SER, gain=5, offset=1, exposure=2ms. _conv.tif sharpened Autostakkert output processed in GIMP.

Clavius: https://www.astrobin.com/406053/?nc=user
Plato: https://www.astrobin.com/406054/?nc=user
Archimedes: https://www.astrobin.com/406055/?nc=user
Copernicus: https://www.astrobin.com/406058/?nc=user

Clavius-5000-frames.jpg
Clavius-5000-frames.jpg (189.98 KiB) Viewed 1835 times
Plato-400-frames.jpg
Plato-400-frames.jpg (157.38 KiB) Viewed 1835 times
Archimedes-500-frames.jpg
Archimedes-500-frames.jpg (178.97 KiB) Viewed 1835 times
Copernicus-1000-frames.jpg
Copernicus-1000-frames.jpg (184.97 KiB) Viewed 1835 times

Dave

Re: Lunar, Celestron C8 + QHY5LII-M + IR Cut Filter

Posted: Thu May 16, 2019 9:23 pm
by turfpit
To help with focus, I zoomed in to 125%.

To set the exposure (I was aiming for around 60% on the histogram), I used the Highlight Over Exposed FX selection. Any saturated areas are displayed in black. The exposure can be adjusted downwards until the black areas disappear. Best to check on a Zoomed in image to ensure the black has really gone. This example shows Copernicus.

highlight-over-exposed.jpg
highlight-over-exposed.jpg (115.22 KiB) Viewed 1832 times

This is the capture of Plato in progress showing the histogram at around 60%. Although the image may look dark, the histogram is a good shape for this type of object. Any lightness/darkness preferences can be addressed at the time of processing.

capture-in-progress.jpg
capture-in-progress.jpg (100.93 KiB) Viewed 1832 times

More information on using the histogram to help with better images can be found at https://docs.sharpcap.co.uk/3.2/#The%20Histogram.

I use Virtual Moon Atlas https://www.ap-i.net/avl/en/start to find my way around the moon.

Dave

Re: Lunar, Celestron C8 + QHY5LII-M + IR Cut Filter

Posted: Sat May 18, 2019 8:58 pm
by numchuck
I usually hate when the moon is up ; but your photos are so sharp -- makes me want to try , as well , to get some lunar captures !

Re: Lunar, Celestron C8 + QHY5LII-M + IR Cut Filter

Posted: Sun May 19, 2019 9:19 am
by turfpit
The Moon is a challenging object. The steps that have helped me here are:
  • focusing zoomed in, >100%
  • use of the saturation (over-exposed) indicator to set a correct exposure
  • aiming for around 60% histogram
I have a JMI motorised focuser on the Celestron. The use of the IR Cut Filter helps with the brightness (or use an IR685 or Wratten #25 red filter).

Some effort (and many failures) went into being able to capture images like this - attending 2 six hour lunar imaging workshops (300 mile round trip) a year apart delivered by Damian Peach helped http://www.damianpeach.com/lunar16.htm.

Good luck with your lunar imaging.

Dave