Luc, Imaged last week under a near full moon at iso 800 with a canon 30D and Orion ED80. It was mostly to test my new mount and guiding software and not a...
Hi Hunter, To be honest and from my experience I think that you were a little lucky ;-) Here is why: Entropy Optimized Dark subtraction is trying to find a...
Hi Luc, I have two M51 images that are each a stack of 40 and 65 subs respectively,taken on different days. I would like to combine the two images to see if a...
I was just about to ask this as well. Getting to the point that I want to stack images from different nights like this. Will be watching eagerly for the...
Hi Joe, Hunter, Sorry to be a little late answering, but I am in vacation right now and I am stealing computer time from an old computer... Anyway, if you have...
Hi Luc Sorry for the delay. Stacked 13 light frames of Eta Carina all very good exposures and sharp plus 13 matching darks. Used median cappa sigma clipping,...
Hi Carl, Sure the single light frame on your web site is full of potential. :-) I will take a look at the file as soon as I am back home tomorrow night (is it...
Hi Luc The image on the web is single exposure, the large file attached is result of the 13 stacked images. Only took 1 bias frame. Regards Carl ... From: Luc...
Hi Carl, Ouch! only one bias frame. That is not a good way to get rid of the bias signal and using it has added its noise to the dark and to the light frames. ...
Luc, is there a way to select the light frame that is used as a reference for stacking. I have light frames from different imaging sessions that are offset...
Hi Joe, Nothing simpler: just right click on the light frame that you want to use as the reference frame and select "Reference Frame" from the context menu. ...
Is there a way to write out calibrated debayered color data from raw dslr frames? I have a set of images that dont seem to want to stack since there are not...
Hi Robert, I am sorry but the short answer is no since the calibrated light frames are not debayerized. The debayerization is taking place just before...
Hi All, After the first part about the base notions and the light frames, here is a second part about dark, bias and flat frames. I know that everybody is...
Hi All, Since a lot of questions about stacking are SNR (signal to noise ratio) related, I suppose that a quick overview might be helpful. First of all, image...
Hi Luc! Please go on whenever your time allows with this wonderful explanations. It is a great summary abt. the theory behind the scene. GREAT!! Best Regards, ...
I have the detection threshold set at the minimum. I have not tried the super pixel mode. I might try that and see how it goes. Thanks Robert ... super ... raw...
Tonight here it is now 43 degrees with a low later of 37 degrees. This weekend, friday and saturday are projected to be clear with lows of 37 and 43 degrees...
Hi Hunter, The information you are looking for is the Dark Signal Doubling Temperature (DSDT). It is the temperature increase for which the dark signal of the ...
Hi Luc, I have believed that as long as you have good master bias, you can scale dark frames to each other. Is it true for just different exposure time or for...
Hi Zbynek, ... scale ... linear? I thought so too before experimenting with my Canon 350D and getting multiple confirmations of my own experiments. In fact it...
Hi Luc Thanks for the explanation. Just one question : If a understand well what you say about stacking two images resulting from two different stacks, My...
Luc, This is a very good explaination about SNR and I appreciate it. Concerning method of composite, I didn't really founded the good method ! If I compare...
Dumb Question Just took 10x6min exposures @ 800ISO (Outside temp aprox10c) with a canon 350DSLR Do dark frames have to match temp conditions? Wouldnt shooting...
Luc, I am agree for all but I have a question about flats. Flats have are not really noisy because the ADU is generally between 30 and 50% of the full ...
Hi Nicolas, I agree that flat field is a different beast and less prone to noise. However, I made a small shortcut in my explanation and the noise of the...
Hi Dimitri, That's the beauty of the File Groups feature ;-) Each light frame is calibrated (bias and dark subtracted, flat divided) independently with the...
Ok Luc, I didn't realize that corner could be more noisy ! again a good idea. Nicolas Outters http://www.astrosurf.com/nico-outters/astro/index.html ... From:...
You want to take the dark frames at the same temp-time-iso as the lights. You do this so that you will have the same level of noise/amp glow as when the...
Hi Nicolas, ... method ! ... details on ... colomn. ... That is strange since kappa-sigma and to a smaller amount auto-adaptive weighted average should...
