UPDATE FROM MABULA
I have had a very rough 2 months unfortunately health wise. I was struck 3x in a row with bacterial infections. The second infection occurred  after a routine hospital checkup and I became very sick. I had to rest and take a lot of antibiotics. Once I was recovering and restarting work 1 month ago, I again became sick. The infection was not yet gone, so even more antibiotics and rest was needed. Needless to say, it took a lot of my energy and I needed a lot of rest.
Finally, the infection is really gone and my energy is coming back step-by-step now and I have started work again. I am terribly sorry to have kept you waiting for support. I will address all outstanding questions and e-mails step-by step and will be on the forum daily from today.
APP 2.0.0-beta47 will come soon as well, a lot of work was already completed before I became very ill, so the release is also nearly ready for you. Beta47 will be much faster actually. Many workflows will be more than 2x faster, mosaics can even be 10x faster than before because registration really received a major boost... all compared to beta46. Â Before I release it, I will make sure that everything is working properly and then I will release it.
Hi,
In my images, I often am challenged by similar results of APP stack and light pollution removal attempts that show in the attachments.
For now this is my equipment:
Canon 5Diii astro modified
Canon 100-400mm f/4.5-5.6L ii
This image of NGC 7822 is at 390mm. 32x300second images.
I just wonder if there is a way in APP to avoid the three rings of brightness. Dark at the borders, a lighter donut, then a darker center. Â
Attachment 1 = Demo_v3a - Stretch to show the issue. Stretch = 10%BG,3sigma,0,0% base, no light pollution removal.
Attachment 2 = Demo_v3b - Stretch to show the issue. Stretch = 10%BG,3sigma,0,0% base, WITH light pollution removal attempt.
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I appreciate any guidance.
Regards,
Andy
Hi Andy,
Do you use flats with APP? If yes, how do you take them? To me it looks like an issue where the flats overcompensate the lights. This is not light pollution.
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Wouter
Thank you. I expect you are correct. I did use flats shot with a light panel. As I am learning AP I think my flats exposure time is too short. Â
On the journey.....
Â
Andy
As a rule the peak of the histogram of the flats should be between 30% and 70%. If your exposure time is too short then the peak will lie to the left of that and you indeed should increase the exposure time.
Wouter
And it probably also depends a bit on how short your exposure was. If it's like 1/1000 of a second, it may also be that the sensor data is not behaving properly. This also is an issue sometimes with bias, take bias at at least 0.05 seconds and flats at around a second(or higher than 0.05) at least. Also make sure that you need to calibrate your flats with bias or darkflats and just once, not twice by accident.
In cases where there is nebulosity everywhere and no obvious areas of dark sky background how do decide where to place the squares?. I am new to APP but have had success with your example of the large magellanic cloud but I downloaded some data to practice on which seemed to be all nebulosity and am at a loss as how to proceed.
Mike Evans
Sorry to have missed your question, in cases like that there aren't many options. I would stretch to the max (30% setting) and up saturation. Then I'd select a few regions where the nebulosity is lowest and see if that works for the overall image.
Thanks, I'll try that
Mike
