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INDI Library v1.8.5 Released (19 Apr 2020)

April 2020 release of INDI Library v1.8.5 introduces new drivers while providing fixes and improvements to existing devices and core framework.

Live stacking methods?

7 months 2 weeks ago 7 months 2 weeks ago by han.k.
han.k
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Live stacking methods? #44721
The first ASTAP version (v0.9.278 ) with "Live Stacking" is available for Linux AMD64 and MSWindows. You can find the new feature in the stack menu under tab "Live stacking"



It will stack all file(s) in the specified directory. If it is finished it will wait for new file(s). If a file is detected which is 20 arcmin away from the previous files (idea Wouter), a new stack will be started automatically. You can save the stack results from the viewer menu .

I haven't tested under clear skies but it seems to work well. Please tell me if this is useful and report possible bug(s) or improvements.
To identify files which are processed , they are renamed to the extension *.fts. You can rename them back with the button at the bottom.

If it works well, then I will compile the program for Raspberry Pi.

pch wrote: Hi,
But the best option is to do the stacking in 32bit floating point, then scale to 16bit for the display.
Patrick

Patrick, that' s no problem. ASTAP stacks always using floating point arrays.

Clear skies, Han
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7 months 2 weeks ago
T-Studio
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Live stacking methods? #44742
very nice.
I was trying to list support for ASTAP in the wish list Ekos alignment module.

ASTAP's Solver is a great help when creating a remote environment with SBC.

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7 months 2 weeks ago
T-Studio
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Live stacking methods? #44745
If live stacking can also be implemented, this is a solution that can integrate EAA into SBC.
(I expect it to be easy to navigate and browse remotely as previously posted.)

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7 months 2 weeks ago
T-Studio
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Live stacking methods? #44746
I will introduce it on my blog.
Great job!

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7 months 2 weeks ago
han.k
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Live stacking methods? #44761
Just released ASTAP version 0.9.279 with some minor improvement. Now the stacking will also restart if the exposure time changes. It also restart stacking when the mount position changes more then 0.2 degrees/12 arc minutes. In the previous version this maximum offset was set by mistake at 20 arc seconds only.

pch wrote: Hi,
Maybe with ASTAP you can also try to keep every frame to redo the full stacking each time, in this case you can use sigma clipping to improve the result. If I understand correctly this is what AstroToaster do.
Patrick

If for Sigma Clip stacking the program keeps all images in memory (e.g. 20 megapixels equals 80 mbyte), the memory usage will rise fast and processing time will increase. You could probably avoid this by using only the first ten images to find statistically the mean and standard deviation of each pixel and to use that to detect outliers in the next images. For the moment, lets first see how the average stacking works and performs. Average stacking using the serial calculation makes it fast and simple.

Han

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7 months 2 weeks ago 7 months 2 weeks ago by han.k.
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Live stacking methods? #44791
This evening, I had a chance to test the ASTAP live stacking during some clear sky moment between the clouds. Noted the following:

- Stacking works well!
Only there is something wrong with star detection because it didn't work well with H-alpha images and the normal stack routine has not problem with them.
- The switch-over between two different object doesn't work proper. While slewing the incoming images confuse the program. For the time being I just had to stop imaging.
- Unicode fonts didn't work well with my Win7 system.
- Memo containing the fits header is flashing too much.

Improvements will come.

Han

One example made during strong wind:
41x10 seconds live stacking with ASI1600 and HEQ5 mount. No guiding. No darks No flats.

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7 months 2 weeks ago
han.k
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Live stacking methods? #44793
Except the switch-over, the other problems should be fixed in v0.9.281. But more testing is required. This is an early release to test the concept.

Han

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7 months 2 weeks ago
T-Studio
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Live stacking methods? #44796
Mr.han

live stacking for EAA, please check Sharp CAP for windows app.
A slider that adjusts the brightness and color of the stacked images can be used conveniently for viewing.

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7 months 2 weeks ago
knro
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Live stacking methods? #44803
wow these are impressive results indeed!! Really looking forward to integrating this feature as well with KStars, just after I finish the ASTAP astrometry integration. Great work Han!

Jasem Mutlaq
Support INDI & Ekos; Get StellarMate Astrophotography Gadget.
How to Submit Logs when you have problems?
Add your observatory info

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7 months 2 weeks ago
han.k
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Live stacking methods? #44806

T-Studio wrote: Mr.han
live stacking for EAA, please check Sharp CAP for windows app.
A slider that adjusts the brightness and color of the stacked images can be used conveniently for viewing.


I will do. But sliders are already available.

I'm trying to modifying an application which was designed to stack images from a stationary telescope with guiding. No guiding is no problems as long you keep the exposures short. Currently there is a concept problem that the application doesn't know what's happening with the telescope. When your continuous imaging and move the telescope you get something like this:




This will stack since a part of the exposure is good but somewhere halfway the operator decided to slew. But this will spoil the stack. Looking into the FITS header of CCDCiel there is no keyword I could use to identify the start slew halfway the exposure. So you either have to 1) suspend imaging automatic after a slew command or 2) add information to the header indicating the mount has moved or 3) ASTAP reads out the mount position. 4) stop manually the exposures

This is something for Jasem (Kstars) and Patrick (CCDCiel) to advice. Step 3 is a big step, so option 1) or 2) look the better option. Option 1) looks to me the best option since imaging and slewing doesn't make sense and any image will be worthless. Maybe this is already available in Kstars, I'm not familiar with it.

Han
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7 months 2 weeks ago
han.k
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Live stacking methods? #44807
Fixed some run time problem with ASTAP release v0.9.282. This version processes all my images from last night, good or bad. :)

Han
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7 months 2 weeks ago
pch
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Live stacking methods? #44809
Han, this look very good!

You can detect if the telescope as moved with the RA and DEC FITS keyword.
But it is necessary to compare with some tolerance because the mount driver can update the coordinates after pulse guide command.

This is probably the most universal way to deal with the problem. For example many people doing EAA use the telescope handpad to move the telescope and the imaging application is not aware of that.
But the most reliable is a Start/Stop button in the stacking application, so it not stack until the user finish to center the object and sometime focus manually.

Patrick

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