"Mixing" Exposures

Mine are OSC images, but I do the same with exposure lengths and with gains, for dynamic range. I used to really, with a 12 bit camera, but stick to single settings for my 16bit one. You should be OK for dynamic range or tonal range integrating as sessions (singly or as separate integrations from one process in the integration tab). So long as you assign your calibration frames (if you use them) to the right sub exposures, it should be OK.

My most-recent image mixed 15", 30", 200", and 600" exposures. Whether it was inadvisable I couldn't say, but it came out pretty ok. APP integrates the various exposures pretty well; I have had less success with mosaicking images that differ wildly in exposure, but APP will handle that too if you have enough patience to sit through the LNC iterations.

It's fine to mix, but it isn't super beneficial yet. What you're probably after then is a HDR integration and APP doesn't support that yet (it's on the list of things to add though).

Thank you, everyone.

I want to take every opportunity to increase the total integration time of a faint object. I've been given several hours of additional luminance frames by a generous person, but the exposure is different and the optics are slightly different as well. I have watched the video tutorials on this topic.

So, I have a good follow-up question: "If adding different luminance frames captured by the same equipment is not very beneficial, then what is the benefit of a multi-person project?" The question is silly, but why is it beneficial in one context but not another? Or am I reading too much into the reply? Clearly, there are various degrees of "beneficial".

Thanks again.

Ok, so to be clear... more data = good. 🙂 The more data you have, the lower the overall noise and the better the signal. Of course you wouldn't want to combine very bad data with good data preferably. But if you combine a lot of nice data, even from different scopes, that will be really nice as an end result for sure. The thing with different exposures is that you usually want to use that to get more detail in over-exposed stars and galaxy centers etc. That specifically is not yet a feature really.

@oopfan

More data is generally better, especially if it is good data. APP doesn't have a dedicated HDR exposure mixing, but its not so important since lower exposures (maybe your case) might have better star color balance (sometimes is the case for OSC cameras). Anyway, it will help SNR assuming there are no major sky background differences and improve rejection algorithms for the background levels.

You could try one curiosity test to see for yourself. Integrated 50 exposures at the longest length, then 50 with the shortest length (or whatever number you have, but ideally more than 20 subs). Then add half and half of each up to the same number of subs and compare the outputs in a similar region at high magnification non the viewer to satisfy your self you are not worsening anything. Then the integration with everything together should in principle be the best scenario for the data assuming no massive deviations in the data sets aside from exposure.

Thank you, Colm. That is great advice!