Image intergration Fail

J

jjhughes53

Well-known member
hello
I doing LRGB images and have been trying to get WBPP to work It runs down fine through Calibration and Costetic correction. It fails Linear Correctionthen seems to read the image I put in for reference and than maybe registers one or two images and fails. So I have been taking the images and manually registering them using the Dynamic Alignment one at a time and then creating masters. It has been tedious when doing 80 to100 images but working up until today. I tried to Image Intergrate the registered images and it runs for a while and then comes up with an error message. It refers to the path to the folder is in and then says: Zero or insignficant PSF Signal Weight estimate.-failed-. I hit the reset button on the Image Intergration panel but there is no change it still fails. Since I can't get the WBPP to work this method is the only other option I have. It worked fine yesterday does anyone have a solution?
Thank You
 
The "Linear (defect) Correction" is not likely something you need to use unless you know what you are doing.
If registration is failing you need to look at the calibrated data (blink it) and make certain it is OK... you should see normal looking images (no black pixels or anything). Then you need to open a few images in StarALignment and prove to yourself they will register. If not, you can determine why. Typically the issue is poor data (star quality) or hot pixels (non optimal cosmetic correction). Of course if the images were not calibrated correctly to begin with...that is the root cause.
 
Thank You I will turn off the Linear Defect Correction.
I checked the images. They look normal and comparable to the ones that Image Intergration combined yesterday. A couple have satellite trails through them. Should I discard them? Some show short star trails but manually register with Dynamic Alignment. Should I discard those? Frankly that is a large number of my images which testifies to my skills. But it is the same camera and settings I have been using all summer. It is a ZWOASI 1600MM pro, same exposure 180 seconds, same gain of 300.
. I do not understand why suddenly they show zero or insignificant Signal Weight.
 
Also I run the images that have succefully made through WBPP calibration and cosimatized and use those to manully register with Dynamic Alignment. When I try to run them through Star Alignment they fail.
 
jjhughes53 said:
Also I run the images that have succefully made through WBPP calibration and cosimatized and use those to manully register with Dynamic Alignment. When I try to run them through Star Alignment they fail.
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Time to make either the images or screenshots of them available.
Insignificant signal means there is oversubtraction and your images *do not* look fine.
If these are narrowband, typically the oversubtraction is to do not using a calibration pedestal.
 
jjhughes53 said:
Here is the file of the registered lum files I am trying to intergrate https://www.dropbox.com/scl/fo/5q01...ey=nuq3xsk88so6f2zoeteyq9fsu&st=quw10spw&dl=0
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I don't think those images are usable for any serious processing. There is just too much drift. You need to work on your acquisition methods: sturdier mount, better polar alignment, shorter exposures, proper active guiding. If your images don't have round stars, you have a problem. And when the stars are this streaked, you can't expect any of PI's PSF-based algorithms to work properly.
 
OK thank You. I have a Paramount MYT and have been trying to work without an autoguider that Paramount is suggesting is possible. Obviously I need to work on that more.
 
The MYT is an observatory-quality mount. Correctly mounted on a solid pier and accurately aligned you could indeed expect reasonable unguided performance, at least for shorter exposures. In truth the problems with your images are not confined to tracking. The "tadpole" shape suggests movement in addition to tracking errors (i.e. the telescope was not rigidly following the mount - it may have been physically nudged or disturbed by the wind). Even the best mount needs guiding unless it is very precisely polar aligned. And the focus is sufficiently off that it is hard to offer further diagnostics. I suggest:
  • devote more time to accurate focus (this is an easy win);
  • ensure the telescope is absolutely rigidly fixed to the mount (and the mount is rigidly attached to its pier);
  • if you plan to run without guiding (even for short exposures) make sure you have polar alignment to sub-arc-second accuracy; this takes time and patience to achieve.
 
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The frame size looks like an IMX298 sensor - but I don't know any astro camera that uses it. What camera and what telescope are you using?
 
jjhughes53 said:
OK thank You. I have a Paramount MYT and have been trying to work without an autoguider that Paramount is suggesting is possible. Obviously I need to work on that more.
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I image on an MYT, and at 0.5 arcsec/pixel can take at least 300 second exposures without any active guiding. You need to ensure that everything in your system is rigid, and you need PEC training and a high quality TPoint model so that the mount's tracking system can compensate for systemic flexure, polar alignment error, and other imperfections.
 
This appears to be a polar alignment error.
I use an MYT and can get 600 second exposures at 1.5"/pixel without any guiding.
 
ngc1535 said:
This appears to be a polar alignment error.
I use an MYT and can get 600 second exposures at 1.5"/pixel without any guiding.
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I misalign the pole with my MYT and the tracking is nearly perfect. This looks like a lot of rotation for a typical small misalignment. Of course, maybe it's not small...
 
If you look closely at the stars there are two distinct bright points, the stars are like little dumbbells. To me that suggests a mechanical issue; rocking on one axis. The OP states all was well prior so that suggests the spring plungers are set correctly hence me asking if the mount had taken a knock. The cam stop mechanism allow the worm to disengage in the event of excessive physical force. I have knocked my MX a couple of time, usually with the top of my head climbing into my observatory dome and the result is exactly what the OP’s image show. Resetting the cam stops takes a few minutes so is worth a try.

Ps a while ago there was a long discussion with Patrick Wallace on the subject of polar alignment aims when using TPoint on the Bisque forums. His advice was that TPoint was very good at mopping up PA errors, other than field rotation and showed you would need to be a long way off, even with wide fields of view, for that to have much impact. His takeaway was close enough is good enough even with a fairly modest number of TPoint sample points along with suitable recalibration if anything changes.
 
Thank You for all your responses. I have recently put my mount in a permanent setup and am still working out the adjustments. To chris.bailey can you tell me where to get instructions in resetting the cam stops as you have suggested?
 
jjhughes53 said:
Thank You for all your responses. I have recently put my mount in a permanent setup and am still working out the adjustments. To chris.bailey can you tell me where to get instructions in resetting the cam stops as you have suggested?
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Lots of info on the Bisque forums. The MyT is a little different to my Mx, the MyT has direct access, the original Mx does not, so best to get it from the experts. It’s not hard to do though.
 
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