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,Â
I am trying to use APP for my astro stacking and processing. I have taken M81 60Sx91 and stacked it together. The resulting image is very noisy. I tried light pollution and background calibration etc. Nothing seem to work. I am not sure what is wrong. Any thing you can identify from this below stacked image, please let me know.
https://drive.google.com/file/d/19_iIuVXCs6akCze1HOXvVWF3KLsWBgF8/view?usp=sharing
Thanks,
Sathya
Your exposure time is 60 seconds? That may be one of the reasons as each image will then likely be close to the readout-noise levels of your camera. Do you use calibration data like darks and bias?
@vincent-mod
Yes. The exposure is 60s. I also use calibration frames. I have 16 darks, 16 flats and 16 darkflats. Â These were taken using ASI533 and WO GT 81 IV, GEM45. I used NiNa to capture.Â
By the way, I am in Bortle 9 area and I have not used any filters.Â
@vincent-mod
Yes. The exposure is 60s. I also use calibration frames. I have 16 darks, 16 flats and 16 darkflats. Â These were taken using ASI533 and WO GT 81 IV, GEM45. I used NiNa to capture.Â
By the way, I am in Bortle 9 area and I have not used any filters.Â
@Vincent-mod Any pointes to know what could be wrong?Â
Yes so the short exposure time, combined with light pollution and no filter will not help to get clean images unfortunately. I would advise to look into using a good filter and then going for a bit higher exposure times.
@vincent-mod
I took around 400+ images each 60S with IDAS D3 filter. I still see the images are noisy.Â
https://drive.google.com/file/d/1Lz4aFgblrdRIK7vkU2eM5ObFTqQDQp0B/view?usp=sharing
Here is the original fit image after stacking in app https://drive.google.com/file/d/1XyS9syqWMYcLgsDrP2W9vSuR5ejr4a1E/view?usp=sharing
What am i doing wrong?
You're exposing a bit too short as I mentioned above, this means you're close to the noise floor of the sensor and that will give noisier results. For this target I would go for at least something like 3 min per sub, longer if possible. I would also add more calibration data, minimum of 40 darks, 60 bias. Also, the light pollution in your area seems high and even with that filter is still quite strong, that doesn't help either.
Noise reduction via software is something for a future version of APP, getting the noise down with a better data gathering method is always better.
That said, I took your first fits file and applied light removal correction and I think that's about the noise level I would expect for 60s.
@vincent-mod Thanks. As of now, I don't have guiding so anything beyond 60sec, the stars start to trail. Â I'll get the guide scope setup and try again. Â I guess, this filter is no use so I would return it.Â
Â
Thank you very much.Â
