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10-04-2016, 11:17 PM   #1036
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QuoteOriginally posted by XLXW Quote
Is there any astronomy astrophotography software out there which will stack Pentax movie images?
Autostakkert2 (freeware) handles a lot of video formats for video stacking of planetary and moon images but I do not know if it works with pentax files (I always used my OM-D for that).
If not you could import the movie file int some video software and export it as single JPGs or BMPs then drag them into Autostakkert with the mouse. Works fine.
Or you could convert the video into lossless AVI and feed Autostakkert with that. There are several free converters on the Internet.

10-05-2016, 12:59 PM   #1037
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If one is really going to have any real success w/ video for Astronomy, one would need to use a dedicated Astronomy Video Cam & leave the DSLR for static captures...
10-08-2016, 01:46 AM - 3 Likes   #1038
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QuoteOriginally posted by SKYGZR Quote
If one is really going to have any real success w/ video for Astronomy, one would need to use a dedicated Astronomy Video Cam & leave the DSLR for static captures...

...but depending on the lens or telescope used and the target one may give it a try.....




This for example is a panorama of six ímages stacks from 1-minute-film-seqences taken with an Olympus OM-D E M5, a Pentax-A 5.6/400 , the pentax 1.4x and 2x TCs with the camera in HD digizoom mode. The final Image is 4549 x 2508 size. It was an easy job and at least a lot of fun

6 Clips from tripod -> Import to Magix VideoDeluxe -> export as JPGs -> drag each sequence into Autostackert (free) -> combined to panorama with Microsoft ICE (free) -> PP with Lightroom CC


If Pentax (like other Brands) would deliver a "lossless HD-crop" for the movie mode that would serve as a lossless digizoom that would be great (also for other video applications).




---------- Post added 10-08-16 at 10:58 ----------

QuoteOriginally posted by Pete_XL Quote
I did my astrothings with my new K3 II in the passed year. Yesterday I put on the good old K5 once more to go for a dim nebula from my suburban light polluted balkony.

I started a new approach on the "Heart nebula with K-5" because I disliked the scruffy stars in the first one. I used a star mask and frequency separation to process stars and background separately.




Data: 45x180s, ISO 800, 80/480 mm, Pentax K-5

Last edited by Pete_XL; 10-08-2016 at 01:57 AM.
10-18-2016, 01:10 AM   #1039
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Stunningly beautiful images, Pete. Well done. Very well done! Thanks for posting them.

10-30-2016, 04:36 AM - 1 Like   #1040
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At the moment I like the K5 more than the K3 II because of the ISO 80 setting. I have the feeling that brighter objects (Galaxies, Star Clusters) are better for the K3 II with higher ISO (800) and shorter exposure stacks and dim ones better for the K5 with lowest ISO (80) and longer exposure.




This is the Cescent Nebula NGC6888 and its neighbourhood from last night shot 30 x 300s with the K5 at ISO 80 from the balcony with bad seeing and hazy skies.
10-31-2016, 12:20 PM   #1041
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Great Pictures

Thanks for sharing

Regards

Ro
11-07-2016, 11:02 PM - 1 Like   #1042
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Posted also in the Astrophotography Group.

Took this w/ the K5ii on 9-2-16 @ 22:35 local. Used the Pentax DA/FE 10-17 3.5-4.5 lens @ f/4.5 set @ 10mm (lower foreground cropped). 120s, 3200iso. Used an I-Optron tracker. White Lighted foreground while exposing....

11-21-2016, 02:17 PM   #1043
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New Glass for the K5ii / K3ii

Posted also in the Astronomy Group

Link here: New Glass for the Pentax's - Beginning and Intermediate Imaging - Cloudy Nights

01-05-2017, 02:46 PM   #1044
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Huge fluctuation of pixel values in BIAS frames

Trying to get some grip on image processing, I started with taking 50 frames with my Pentax K-5. The settings are as follows:
  • Manual setting
  • ISO100
  • Exposure 1/8000s
  • Cap on viewfinder and lens.
  • K-5 completely in the dark at 22°C
  • Frame format DNG
  • Interval between frames is 10sec.
  • All noise processing, filtering, correction performed by the K-5 were switched off.
These are the conditions for shooting BIAS frames as far as I understand.
The frames are imported in Python using rawpy (the DCraw modules allowing to read and interpret DNG frames).
The frames are uploaded in rgb 16 bit format what gives me an array with the rgb channels.

I took at random one pixel somewhere in the middle of the frame and compared the channel intensities for all frames in the sequence.


Bias frames show the error of the zero value measured by the 14bit ADC of the K-5, and I expect that this error values is rather stable and small.


To my big surprise I obtain the following result:



The same pixel (pixel [1500, 1500]) has fluctuating values of the channel intensities with up to 25% of the maximum value that can be represented between the different frames taken.
For me this is huge and probably something went wrong in the reading of the frames. If I divide the rgb16 array in Python by 256, I get an 8bit representation of the frame that can be visualized.
With light frames made with the same camera and stored in a DNG file, my Python procedure allows me to see the 8bit picture in the real colors.

My question to the forum is, whether this fluctuation of the pixel rgb values from frame to frame is normal and to be expected?
Thanks in advance,

Stefan

Last edited by noste99; 01-05-2017 at 04:47 PM. Reason: Issue with Picture
01-05-2017, 03:06 PM   #1045
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QuoteOriginally posted by noste99 Quote

To my big surprise I obtain the following result:
Hey Stefan,
the picture is not visible (at least on my PC)
CheersPete
01-05-2017, 04:48 PM   #1046
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QuoteOriginally posted by Pete_XL Quote
Hey Stefan,
the picture is not visible (at least on my PC)
CheersPete
Sorry Pete, I tried again and it should work now.
Regards,

Stefan
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01-06-2017, 03:43 AM   #1047
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QuoteOriginally posted by noste99 Quote
Trying to get some grip on image processing, I started with taking 50 frames with my Pentax K-5. The settings are as follows:
  • Manual setting
  • ISO100
  • Exposure 1/8000s
  • Cap on viewfinder and lens.
  • K-5 completely in the dark at 22°C
  • Frame format DNG
  • Interval between frames is 10sec.
  • All noise processing, filtering, correction performed by the K-5 were switched off.
These are the conditions for shooting BIAS frames as far as I understand.
The frames are imported in Python using rawpy (the DCraw modules allowing to read and interpret DNG frames).
The frames are uploaded in rgb 16 bit format what gives me an array with the rgb channels.

I took at random one pixel somewhere in the middle of the frame and compared the channel intensities for all frames in the sequence.


Bias frames show the error of the zero value measured by the 14bit ADC of the K-5, and I expect that this error values is rather stable and small.


To my big surprise I obtain the following result:



The same pixel (pixel [1500, 1500]) has fluctuating values of the channel intensities with up to 25% of the maximum value that can be represented between the different frames taken.
For me this is huge and probably something went wrong in the reading of the frames. If I divide the rgb16 array in Python by 256, I get an 8bit representation of the frame that can be visualized.
With light frames made with the same camera and stored in a DNG file, my Python procedure allows me to see the 8bit picture in the real colors.

My question to the forum is, whether this fluctuation of the pixel rgb values from frame to frame is normal and to be expected?
Thanks in advance,

Stefan
Stefan, I am not sure if I got the problem right. Such a fluctuation of pixel intensities that should normally be around zero at ISO100 should result in a heavy noise pattern. Do you see that behaviour only in the data or also visually in the images? At ISO 100 and 1/8000s the noise level should be quasi not existing and the pixel intensities below lets say 5% or 100% (in hot pixels).


What makes me a bit skeptical is the sharp sawtooth character of the curves for the 1.500/1.500 pixel. The teeth are very distinct and quite regular in the succession of the frames. Most of the time the data - especially the blue and at a lower level also the green - tend to be either zero or very high. E. g. in the blue channel nearly each series of 0-value frames is followed by just on frame with + 5.000 intensity and so on. So STD and average perhaps do not represent the real nature of the effect. If the fluctuation that occurs on a high level in all lines and collums had a "technical" source in the internal readout process I would expect a more erratic behaviour. Is it possible that the data show a systematic artificial effect resulting from the data acquisition method?

So I have written a lot just to admit that I have no idea what could have happened there....
01-06-2017, 06:55 AM   #1048
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QuoteOriginally posted by Pete_XL Quote
At ISO 100 and 1/8000s the noise level should be quasi not existing and the pixel intensities below lets say 5% or 100% (in hot pixels).
Dear Pete,

I happy to see that you confirm my initial expectation! Indeed, noise should be very low with these settings.
I do not see problems in pictures I took, and that makes me think there is a problem with the data import in Python or my interpretation of data in Python is wrong.

This evening I will try to reproduce the data sequence with ImageJ and report back.
Thanks a lot for your reply!

Stefan
01-06-2017, 10:37 AM   #1049
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QuoteOriginally posted by noste99 Quote
Dear Pete,

I happy to see that you confirm my initial expectation! Indeed, noise should be very low with these settings.
I do not see problems in pictures I took, and that makes me think there is a problem with the data import in Python or my interpretation of data in Python is wrong.

This evening I will try to reproduce the data sequence with ImageJ and report back.
Thanks a lot for your reply!

Stefan
Stefan, let us know what comes out
Cheers Pete
01-09-2017, 12:51 AM   #1050
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QuoteOriginally posted by Pete_XL Quote

Stefan, let us know what comes out
Cheers Pete
Hi,
I succeeded reading and interpreting the DNG header. Next I will extract the image from it. That's the interesting part. Once I have the image byte per byte stored in a 3d array, the real work begins on the images.
With the header info it will already be possible to do some quality checking between my observation journal (settings of the camera, time and date etc.) to be enriched with platesolving and storing all the info in what will become the FITS header.
Stefan
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