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Topics - miska

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General / Eclipse image processing
« on: 2017 August 29 15:14:17 »
Hi !

I am surprised to not see here more threads about eclipse image processing. So here we go...

I took some bracketted images of the eclipse (using a Sony alpha 7RII + Canon 500mm f/4, on a EQ5 mount). I have a large number of bracketted shots, ranging from ~1/4000s to ~3s that I would like to combine into a "super HDR" image.

I tried with Lightroom, but it didn't work. So I thought I'd give PI a shot. I have used PI for my DSOs but processing the eclipse-series seems very different, and I don't know how to start / what the best workflow is.
So how would you proceed with the image combination, and then processing ?

On the individual frames, I already see what I want to show in the final image: red protuberances, coronal structures reaching far away from the sun, earthshine on the lunar disk... So the data seems ok. Now how to make all those features into a single image ?

To make things easier, for the moment, I don't necessarily need to increase SNR by adding several frames with the same exposure (although, it would be cool if it could be done somehow as part of the image combination process).

So how do I start ?
Feel free to share some of your eclipse shots (including how you processed them) if you wish...

General / BPP optimization
« on: 2016 November 10 04:02:09 »
Until now, I have been running BPP pretty much using the default settings for all the steps. I have been happy with the results, but now have a challenging object (very faint Halpha emission), that I would like to get out of my image.
So I'd like to optimize a bit the stacking process.
What steps should I do and begin with ? What do you think are the most important parameters to optimize ? I think I need mostly to tackle image integration.

The data I have is Canon 6D DSLR images, with and without a clip-in Halpha filter.

Thoughts and ideas ?

Bug Reports / BPP forgets file lists with new instance
« on: 2016 July 29 13:43:34 »
I think something has changed in the behavior of BPP. It used to be that you could enter all the files (light, flats, darks,...), reference  files and so on into the GUI. Once ready, you could pull the triangle onto the desktop, to save this BPP instance with all it's values, ready to process. I could then prepare all my BPPs, and then launch them at another time.

When I do this now, re-opening the instance has lost all the files to be processed (lights, flats, darks and biases), but the reference and output directories are still there.
Is this a bug ?

MacOs X, 10.9.5, PI, BPP version 1.42.

Thanks !


I use BPP and it works great. However, in one particular case, I think there should be an extra warning, or it should not even start.
I use Canon 6D files. It is well known that Canon has a fixed bias value in their raw data.

My problem: IF you don't input some bias files in BPP, but still use flats, then you basically get garbage out. Very blotchy images, with big rings around the center. Completely unusable.

So my suggestion:
- When BPP detects that it is using Canon data, and bias files are not given, just generate a constant bias over the whole image with the appropriate (Canon) value.
- If that is not possible, put a big warning that No Bias + Flats + Canon RAW --> Disaster.

It took me a while to figure this one out. Of course, one should always use all the calibration frames, but I thought that bias is not such a big deal...

General / Quick and dirty BPP in the field
« on: 2016 March 10 23:29:58 »
Hi !
I am using BPP to stack my DSLR images, and that works fine. It is quite a slow process though, even on my desktop.

Now, when I am in the field, I would sometimes like to do a quick and dirty stack of some images, just to see if my object is in my field of view or not (if it is not visible in one exposure - sky limited). My laptop is slower than my desktop, so BPP as it is seems too slow for this.
So is there a way to either accelerate (by a lot !) BPP to get a quick answer ? Or is there a better tool for this ?

Thanks !

General / Aperture photometry - number of stars
« on: 2016 March 02 07:47:06 »
Hi !
I am trying to use the aperture photometry script to estimate the magnitude I reach after a given exposure time.
The script runs fine. However, when I look at the results, I see that many stars detectable by eye are not detected by the script (the star that are detected have a green square on them).
So how do I get more faint stars into the routine ?

I have increased the magnitude of the catalog stars to get ~700 stars in my field. But still, I only get about ~80 PSF stars analyzed in the PSF extraction step.
I am a bit fuzzy as to what variables I need to tweak...

Thought ?
Thanks !

General / Batch Batchpreprocessing
« on: 2016 February 09 00:44:29 »
Hi !
Sorry for this perhaps basic question, but here goes...
I like to use Batch Preprocessing for my DSLR astro-images. So I prepare the batch (load all the lights, darks, flats), configure everything to be ready to go. Then I let the thing run for a looooong time.

Now, what I would like to do, is prepare several Batch Preprocessing sessions (several objects taken during one night for example), and then launch them so that they execute one after the other, but without my intervention. So a Batch BatchPreprocess. That thing would run for a much longer time (obviously) than just one job, but I wouldn't have to baby-sit it. Now I do: Prepare, launch. Wait. Prepare, Launch. Wait. What I want is: Prepare, Prepare, Prepare, Launch, Waiiiiiiiit. Done :-)

Is this possible ?

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