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Topics - John_Gill

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1
Off-topic / Crop and process or process and crop ...
« on: 2020 February 21 04:48:16 »
Hi,

Is it better to crop the image and then process or process the image and then crop?

space is not black
John

2
Bug Reports / SubFrameSelector Graphs
« on: 2020 February 18 04:52:57 »
Hi,

Running PixInsight 1.8.8.4 Ripley on a Windows 10 version 1909 build18363.657

Just re-processing some older images and SFS crunches all the images and calculates the weighting and all is good, except that the graphs do not display.

The other issue is not a bug, but I suspect bad data.... I add the "bad images" and Measure Subframes and then the Weighting formula has a red X next to it and in the Measurements window the FWHM and ECC show -nan(ind) ..... any ideas as to what is wrong?

space is not black
John

3
Off-topic / Synthetic Flats
« on: 2019 December 30 09:05:33 »
Hi,

I have been processing some old data which turned out to be quite horrible, mostly because the flat were bad.  Anyway, I used David Ault's tutorial to create synthetic flats and I was able to create a great image.  My question, should synthetic flats only be created/used as a last resort?

space is not black
John

4
Bug Reports / LRGB Combination
« on: 2019 October 31 03:02:55 »
Hi,

I think this is just a cosmetic issue ..... Run LRGBCombination and choose any setting and change the Channel Weights (LRGB) to any value and then apply ... a new image is created .... no problem.  Now when using the History Explorer, select the newly created LRGBCombination image and you will notice that the result order is shown as RGBL.

space is not black
John


5
General / Mosaic of a mosaic not aligning correctly...
« on: 2019 October 23 00:15:26 »
Hi,

Over two nights I took 2 sets of images - NGC261 and NGC345 in both Ha and Oiii of the Small Magellanic Cloud. I pre-processed these 4 image sets and then stopped before stretching.

Using StarAlignment (Register/Union - Mosaic)  I create a 2 panel mosaic of the Ha and another 2 panel mosaic using the Oiii. Both mosaics align 100%and look decent.  There is a lot of black space around each image due to the StarAlignment image rotation. So I now have 2 x two panel mosaic, namely "mosaic_Ha" and "mosaic_Oiii".  Placing the images over each other, I can see the alignment looks great.

I now re-register the two mosaics to each other and 100% result.  All is still good. I now combine these images using ChannelCombination or LRGBCombination.
Now the problem starts .... When zooming into the result, I can see that the Ha and Oii on the left image match up but the filter colors on right image do not match up.  To the point that the stars are off by about 1.5 stars (I hope that makes sense). 

I have tried stretching the images before doing the ChannelCombination, but with the same result.

Any ideas will be appreciated
John

6
Off-topic / To be a better astro-imager ....
« on: 2019 July 22 01:33:16 »
Hi,

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  :-\

7
General / Script Editor
« on: 2019 April 11 05:20:03 »
Hi,

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
John

8
General / Cannot apply mask to image
« on: 2019 March 18 01:51:59 »
Hi,

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 ……

space is not black
John

9
General / The many shapes of Alnitak
« on: 2019 January 22 04:18:17 »
Hi,

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 ....

space is not black
John

10
General / SFS and PCC no graphs generated
« on: 2019 January 04 06:22:23 »
Hi,

I recently updated my PixInsight to 01.08.06.1448 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.

John

11
Off-topic / Moving from DSLR to LRGB & NB imaging
« on: 2018 December 29 00:19:10 »
Hi,

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".

space is not black
John

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

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:

space is not black
John

13
Off-topic / New scope recommendations
« on: 2018 July 10 03:07:04 »
Hi,

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
John

14
Off-topic / Calibration Frames
« on: 2018 July 03 23:40:11 »
Hi,

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

Look up
John

15
General / Black artefacts in some star centers.
« on: 2018 May 22 02:38:00 »
Hi,

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
John

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