Monday, July 30, 2012

Comparing various processing techniques

Well, I actually woke up late enough (1:30) but forgot about the fog... So, no combined shots for now :-(

Pre-processed all images. Here are the results after some basic post-processing (background color adjust, DDP Stretch - I tried Sharpening and Noise reduction too, but they don’t seem to have any impact):



Comparing different noise corrections:

1. None



2. With explicit darks



3. With camera noise reduction



Can’t see much of a difference, but you can clearly see the vignetting.

So, here are the 2 different noise reductions with and without flat correction:

1. Noise reduced with explicit darks:



2. Noise reduction from the camera



The vignetting effect is clearly visible - shows how important it is to take the flats (though next time I need to take them the correct way - with ISO 100 and proper shutter speed).

But there isn’t a visible difference between the two different noise reductions. I guess that doesn’t matter too much.

Now, I have to get better with color corrections (so far I just applied some default post-processing steps). And also I have to do a better job in focusing. The following is a zoom into this image:


I guess, that’s where I have to figure out how to do computer-supported focusing - don’t think I can do it better with the naked eye (the strange diagonal line is from Nebulosity - still don’t have a license).

After playing with all those tools, I’ll probably stick with DSS, Nebulosity and I hope that DSLR Shutter will work with my DSUBS cable. These are fairly simple and should work for me for some time. Nebulosity has a lot of manual pre-processing that I could use if DSS fails.

Just got the notification that the focal reducer was delivered (to work) and that the DSUBS cable will arrive on Thursday. Can’t wait to try it.

Also got a reply from the Avistack guys - seems as if it’s not that easy to load .mov files. But considering that I am not able to take a movie of the moon that’s not overlit, I won’t need this any time soon anyway.

Have to figure out what pictures I want to take tonight.

… actually not - it’s completely overcast.

So, I’m reading more on focusing. I am somewhat surprised that nobody came up with a mixed software/hardware solution that does this automatically. All solutions rely on doing the correction to achieve focus manually.
For the telescope, a Bahtinov mask sounds like a fast way (or these are way cheaper) - but need to measure the outside diameter of my telescope. Or Stilletto to get really fancy. Not sure what to do when I just want to take photos with a lens and not the telescope.