Wavefront analyser script

S

sbasa

Member
Hello

I wanted to test your Wavefrontanalyser script on a 1.3m telescope (at about F/7) that we have at the Observatoire de Haute Provence. First of all, the mirror diameter seems to be limited to 1m (impossible to enter 1300mm for exemple) , which is a pity. Can we modify the script to accept larger diameters?

Even more annoying, the script tells me that it doesn't find the image defocused, even though its size in pixel is well within the requested range. Do you have a hint to overcome this issue?

Thank you very much,
Stéphane
 
I am not an expert, and I have never used this script ... but:
I think that simply editing the file "...PixInsight\src\scripts\mschuster\WavefrontEstimator\MainModel.js", changing line 76 to:
Code: 
   this.maximumApertureDiameter = 2;
will increase the maximum aperture to 2m. I could not see any other obvious dependencies.
It may be that your images will be successfully processed once the parameters are correct.
 
Thank you very much for the suggestion, it accepts now 1.3m. But the image analysis, it doesn't work yet unfortunately...
 
I don't know much about this, but I'd be interested to have a look if you could post (somewhere accessible):
  • one raw in-focus frame
  • one raw out-focus frame
  • the basic parameters of your optical / camera system (as required by the script)
 
Thank you very much for the proposal and there are several files at this address (too large otherwise): https://nuage.osupytheas.fr/s/8egTDRCiSYrtCqd

I did several defocus as the proposed sized in pixel looks small according to my previous Roddier experience. Concerning the elements, here it is:
- Telescope: 1.3 m with a focal of 9.640 m (F/D=7.4)
- Camera (Sbig ST8300M) with a pixel scale of 5.4 um.

I will be very curious to understand why it doesn't work.
 
Although the images seem to be saved at 16bit resolution, the FITS file header identifies the file as 32 bit, which results in 32bit normalisation in PI. As a temporary fix I multiplied all pixels by 2^16 (using PIxelMath), but if you can configure you software to save as 16 bit files it might make things easier.
The documentation states "Observations must be on-axis". Since dithering is encouraged, I presume that this means "approximately on-axis", but your images are well off-axis.
I estimate your "intra_05mm" and "extra_05mm" images to be ~200 pix diameter, which is comfortably in the specified range.
While it is hard to judge seeing on the basis of a single frame, it would be nice if the images were a bit more stable. How? I can only quote the documentation:
Observe near the meridian, observe in good seeing conditions, increase frame exposure time, increase the number of combined frames, average the results of several data sets.
Click to expand...
 
Oh, excellent, I hadn't seen that problem. Saving it in 32 bits won't be difficult (I just wanted to give it a try). It would require several exposures too, I totally agree.

Were you able to extract some values, just for curiosity?

Thanks again!
 
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