Back to the Moon

It's been a couple of years since I did any Solar System imaging with my focus on bettering my DSO imaging with ZWO imagers. The super low noise, sensitivity, cooling and high dynamic range have allow me to do DSO imaging even when the moon is in gibbous phases. I never really tried this with my old  uncool Meade DSI II Color camera. And with precious few nights in the USA northeast DSO imaging was prioritized at every opportunity. 

This time of year seeing in the Mid Atlantic States tends to be mediocre thanks to current the path of the jet stream favoring DSO imaging over more seeing sensitive  lunar and planetary imaging. Despite this I recently decided to pull out my trusty old Celestron NexImage5 Solar System Imager on a recent first quarter moon night. Seeing was only a 3 on Clear Sky Charts. 

The lunar images can be seen at this entry in my Solar System Imaging with Celestron NexImage5

What I learned from post processing M42 in Paintshop Pro X9.

In my last posting I alluded to simplifying my post processing using M42 as an example. My goal has always been get a aesthetically pleasing image with as few steps as possible. 

I use Corel Paintshop Pro X9 (Standard).  In the past I would thrash around trying various aggressive histogram adjustments, color balance adjustments, brightness and contrast, curves and saturation adjustments. The result would be a history of many steps (often 10 or 12) that if saved as a script would not translate well to the next image. One thing all post processing had in common was my first step started with histogram stretch then histogram adjustment to bring out the faint areas. 

I have found, after applying a histogram stretch, I can apply a gentle histogram adjustment (Gamma: 1.3-1.5, Appearance: between -3 and -5) four to seven times to bring out the faint areas. These initial steps for  7x histogram adjustments were saved in a script that can easily be edited to change Gamma and Appearance values. I also selectively deleted histogram adjustment steps to give 4x and 6x scripts. 

After applying the histogram adjustment scripts I use white balance to eliminate the excessive green cast: more on this below.  The Curves dialog is adjusted to further adjust color balance and contrast to bring out faint nebulosity or the outer parts of galaxies. Color saturation and hue are more subjective and are applied case by case.