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Topics - John_Gill

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Off-topic / To be a better astro-imager ....
« on: 2019 July 22 01:33:16 »

A couple of questions ….

1 - With doing NB or LRGB imaging of an object over multiple night, do you image one filter per night or run a sequence of images with all the filter each night.

2 - When looking at the stars in an image, how far do you zoom in to see if there are elongated or funky stars (especially in the corners).

Any pointer in this regard will be appreciated
John  :-\

General / Script Editor
« on: 2019 April 11 05:20:03 »

I use the "Script Editor" as my recipe notepad when processing.  Is there anyway to re-size the window as it seems to have a "hard" limit to the minimum size.  (A bit like the "Processing Console" window).

space is not black

General / Cannot apply mask to image
« on: 2019 March 18 01:51:59 »

I was re-processing an old image and got to the final stages and wanted to apply a star_mask to the image.  So I drag and drop the star_mask to the image, but the image "tag" does not turn brown indicating that a mask is applied.  mmmh, so I tried to apply the mask a little more carefully and I see the "small square icon" appear and drop the mask, but the mask is still not applied.  I created another star_mask, a luminance mask and a range mask and try to apply any of these masks but nothing works.  I saved the project and restarted PixInsight but the same issue persists.  If I look at "History Explorer", I can see that no mask has been applied to the image.  I then created a clone of the image and I can apply any mask to the clone image.

Anyway, I have completed the processing, so not a major problem, but if someone has an idea of what went wrong ……

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General / The many shapes of Alnitak
« on: 2019 January 22 04:18:17 »

Attached is my first venture into NB photography.  The image has only had a Histogram stretch.
Captured with APM apo 107/700 scope and ZWO 1600MM (mono) camera with a Ha filter.
The exposure was for 300 seconds and a gain of 75.

Can someone explain the multiple shapes of Alnitak and how to avoid this in the future and
perhaps how to fix this now ....

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General / SFS and PCC no graphs generated
« on: 2019 January 04 06:22:23 »

I recently updated my PixInsight to and have now re-processed an old image.  I notice that after doing a SubframeSelector there are no graphs available.  I also notice that after applying PhotometricColorCalibration, the graph window is generated but with no content.

I am sure I clicked something (by mistake) ….
Any help will be appreciated.


Off-topic / Moving from DSLR to LRGB & NB imaging
« on: 2018 December 29 00:19:10 »

This year Santa delivered a ZWO 1600MM Pro (cooled) camera and a filter wheel with lots of filters.  What capture software would you recommend and should I go with ASCOM drives or "native mode".

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General / Add satellite streak
« on: 2018 November 24 12:17:03 »

I have 25 x 6 minute DSLR images and in 3 of the images I have a satellite streak.  (It took about 15 minutes to cross the field of view)  The calibration process eliminates the streak, but I want to keep the streak  :tongue:

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Off-topic / New scope recommendations
« on: 2018 July 10 03:07:04 »

I currently use a Celestron 8" EdgeHD scope for astro-imaging and I am in the market for a good 4" scope.  I have about $ 3000 to spend and I have narrowed down my choice to the 4 scopes listed below.  Perhaps the experts can help me get the best bang for my bucks.  If there are other better scopes, in a similar price range, then please feel free to make suggestion, recommendations, etc etc  …. :P

TS Optics Imaging Star 100 mm f/5.8 Quadruplet Astrograph - FPL-53 Apo Objective
APM APO Astrograph 107 / 700 mm - f/6.5
Explore Scientific FCD100 Series 127mm f/7.5 Carbon Fiber Air-Spaced Triplet ED APO
Williams Optics 2018 Gran Turismo 102 Twenty Years Anniversary Edition

Look up

Off-topic / Calibration Frames
« on: 2018 July 03 23:40:11 »

When taking calibration frames (flats, darks and bias) should the dew shield on the scope be removed or left in place.

Look up

General / Black artefacts in some star centers.
« on: 2018 May 22 02:38:00 »

Using a APM APO 107-700 refractor and Canon 600d DSLR.  I have 3 hours of data from night 1 and a further 1 hour from night 2.  Each batch was processed separately and they look good.

I then took the "Debayered" images from each night and combined them with StarAlignment, ImageIntegration, LocalNormalization, DrizzleIntegration, DynamicCrop and PhotometricColorCalibration.  The result was great except about 40 stars scattered across the image have black artifacts in their centers.  These are not the brightest or big fat saturated stars.  I tried doing a " Repair HSV Separation" and then ChannelCombination, but that didn't help. I guess I can use CloneStamp but would prefer to fix the issue.

Any ideas would be appreciated.
Look up

General / too many stars in the image
« on: 2018 May 07 07:37:10 »

I did some imaging last night and after pre-processing there are a billion stars covering the entire image and the nebula (mmh, sometimes we complain about too few stars).  So I now want to remove just the smallest stars without destroying everything.

I ran the script "Extract Wavelet layers" then selected Layer01 and binarized the Layer01.  Then used Pixel Math "Image - Layer01" but the result is not great.

Is there a better way and should I do this in the begining or end of the workflow?

Look up

General / A brown mask
« on: 2018 April 05 00:30:21 »

I notice in one of my images there is some faint brown nebulosity that I would like to enhance.  When using "RangeSelection" I get the brown and red and blue nebulosity.  Using "ColorMask" I get all the other colors but no brown.  Is there a way to mix colors to produce brown/orange/pink masks or somehow isolate these different colors?

Look up

General / Big Pink Stars after ArcsinhStretch
« on: 2018 March 13 12:04:28 »

I have recently tried the ArcsinhStretch and have had some success.  I am now re-processing some DSLR images from last year (due to clouds and rain).  Anyway, I do LocalNormalization, DynamicCrop, PhotometricColorCalibration, Automatic or DynamicBackground Extraction.  I then run Extract CIE L* Component, Stretch and apply as a mask and Invert the mask. Then MultiscaleLinearTransform for noise reduction.  After I apply ArcsinhStretch, the big and bright white stars have big pink cores.  But if I stretch the image with Histogram Transformation and ScreenTransferFunction then no pink stars ....

Any ideas or suggestions cos I am tired of seeing pink stars ....

Wish List / Re-sizeable Process Console Window and others issues
« on: 2018 February 10 04:57:11 »

Process Console
Please can you make the Process Console window be re-sizeable ....

Undo Redo
After applying a process to an image and then selecting "Undo" and "Redo" to evaluate the change the image goes "white" and then the image is "repainted" on the screen.  When trying to see the difference to the fine details, the "white screen" disturbs my vision.  I know that the issue is the graphics card but on the laptop there is not much I can do about the graphics.

Progress Dialog and Bar
When applying some processes, a dialog box appears with a progress bar in the middle of the screen, perhaps this can be moved (and made smaller) to the bottom line of the screen where the "workspace" and "readout" info appears.

Waiting in anticipation ....

Bug Reports / Photometric Color Calibration
« on: 2018 January 29 10:37:26 »

I am busy re-processing some DSLR images with PCC and notice the following error in the Process Console.  The PCC process completes successfully, so maybe it is just a cosmetic thing.

Catalog stars: 1941
1 view(s)
485 star(s)
256 PSF fittings
Found 5 stars with invalid position
Reference stars: 256
Validating reference stars
Stars with problems: 6
Calculating image noise: sigma=4.306 count=18.98% layers=4
Multiscale median transform: done
Multiscale reconstruction: done
Normalizing sample values: done
Aperture Photometry:
  Aperture: 34.000000 px
  Image resolution: 0.444206 sec/px
** Warning [162]: C:/Program Files/PixInsight/src/scripts/AdP/AperturePhotometry.js, line 2726: reference to undefined property pixelsBkg[(x + (y * imageWidth))]
Calculating photometry: Processed 256 stars in 0.737000 seconds
Astrometric error: RMSx=0.0374" RMSy=0.0498" RMS=0.0622"
Writing output file: C:/Users/JohnG/AppData/Local/Temp/PCC_R_TZVGL0BJU5T6.csv
Invalid out format

Any ideas or thoughts.

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