Mar 28 2026 APP 2.0.0-beta40 will be released in 7 days.
It did take a long time to have the work finished on this and it will have a major performance boost of 30-50% over 2.0.0-beta39 from calibration to integration. We extensively optimized many critical parts of APP. All has been tested to guarantee correct optimizations. Drizzle and image resampling is much faster for instance, those modules have been completely rewritten. Much less memory usage. LNC 2.0 will be released which works much better and faster than LNC in it's current state. And more, all will be added to the release notes in the coming weeks...
Update on the 2.0.0 release & the full manual
We are getting close to the 2.0.0 stable release and the full manual. The manual will soon become available on the website and also in PDF format. Both versions will be identical and once released, will start to follow the APP release cycle and thus will stay up-to-date to the latest APP version.
Once 2.0.0 is released, the price for APP will increase. Owner's license holders will not need to pay an upgrade fee to use 2.0.0, neither do Renter's license holders.
Last week I received my DSLR: a Nikon D7100 which I want to use next winter for capturing deep sky. It gives a very nice FOV (3 x 2 degrees) with my 80 mm F5 Esprit APO. In search for the best ISO setting I'm going to try different settings in combination with different exposure times. Since I'm going to use APP for processing these frames I would like to ask my question here about the calibration frames and the ISO setting.
APP uses the BIAS and flat frames to generate a master flat. It also uses the flat and darks frames to generate a BPM. This BPM is nothing more then a bitmap. After creating the master files (master dark and master flat) APP calibrates the light frames with both the master dark and master flat; not the master BIAS, because the BIAS signal is already present in the master dark.
Therefore I was wondering if it would be a problem if I shoot the BIAS and flat frames at the lowest ISO setting (100) and use another ISO setting (200, 400, 800 or even 1600) for both the dark and light frames, since the BIAS frames are only used to calibrate the flats and the darks (which will have the same ISO as the lights) are used to calibrate the lights.
Hi Jeroen,
Thank you for your question.
It won't be a problem. I do this myself with my DSLR data.
For instance, I shoot light frames at iso 400 with my Nikon D610.
Then I make darks with the same exposure and iso as the light frames, because these darks are for light frame calibration.
I always create the flats with ISO 100, and I shoot flat darks with ISO 100 and the same exposure time as the flats (If you use a masterbias, then shoot the bias with iso 100 for flat calibration). These are used to create a masterflatdark (or masterbias) to subtract from the flats.
Then when you calibrate the ligths, you load the masterflat (ISO 100, calibrated with ISO 100 masterdarkflat/masterbias), the masterdark(of iso 400), and your BPM.
For BPM creation, the iso value has minor influence, so you can just use ISo 100 flats and iso 400 (or higher) darks to create the BPM.
Let me know if this answers your questions.
Mabula
p.s. I intend to rebuild the whole calibration engine soon, including dark frame scaling, so chances are that within a couple of weeks/months time, calibration will be simpler in the sense, that APP will solve this for you and will use the calibration path that leads to good calibration. So the engine will and must become smarter 😉
Hi Mabula,
that's the answer I was hoping for. Yesterday I already shot a set of BIAS frames at 100 ISO (the same as the flats) and a set of dark frames using the same ISO setting and exposure time as for the lights. The only thing I have to do is shoot a set of dark flat frames with the same ISO and exposure time as the flat frames to calibrate the flat frames.
Shooting the flat frames was a problem with the high ISO because the exposure time would become too short, so I not only had to dim the flat field generator but I also had to reduce the ISO setting. I'm hoping for a clear sky tomorrow so I can start finding out the best exposure time for this DSLR.
Regards, Jeroen
Yes, indeed, in most cases, you'll get much better flat frames if you can increase their exposure time 😉 by lowering gain or ISO of the camera.
Let me know if it works out okay 😉
Mabula
