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My First Mono CCD Image and PixInsight Processing - Dont Laugh.... :-)


kirkster501
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NA Nebula Wall area.Sorry for strange orientation, I have not got that far yet!

I grabbed this monday night and I am chuffed very much! :) I am on the CCD road at long last - but at the very beginning of that road. This is 40mins of Lum (8x300s) and 10 mins each of RG and B (4 x 150s). Guided and all the subs were fine. No Darks and using BIAS and 20 flats per LRGB filter. I am using Pixinsght alone to process and preprocess. I am not too bothered about the slightly bloomed stars at this moment. I was cloud dodging and desperate to get something in the can after 5 weeks of ownign my Atik 460 and it got to 02:00 AM and I needed to go to bed. Hence not much colour data. I used 1x1 binning on the Lum and 2x2 on the colour. Scope was my ED80 and I used my IDAS Hutech 2" LP filter.

There are issues though. What are those faint vertical lines doing there? I am powering the 460 and the EFW2 from one 12V Powertank if that has any bearing? There is something amiss with the alignment of the colours. I have played with this loads in Pixinsight and cannot get this to got away. There is also a tad too much green. My rejection maps were quite bright as well on all colour high channels (not so much luminance strangely). Also for the life of me, I could not save as jpg even after a Pixinsight screen stretch of the histogram so in the end used windows screen capture.

Anyway, its a start. I will be looking for lots of assistance moving forward :) I am all ears for comments and suggestions. This image is not winning any prizes!

Thanks for looking,

Steve

Mono

post-16295-0-00903700-1376573008_thumb.j

Colour

post-16295-0-22912700-1376572283_thumb.j

Edited by kirkster501
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They look very good to me Steve. I see what you mean about the vertical lines, they are there on the mono as well. It looks like some sort of artifact from the camera, but might be something from the stacking. If they are from the camera, darks should get rid of them.

Robin

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Did you just use the screen transfer function to stretch the images? If you did this only effects what you see on the screen, not the image, so if you save the file it will be unchanged and black.

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Really appreciate your thoughts there guys.

So the lines are being inrtroduced by PixInsight in some way. Below are fresh from the camera L and R subs (some reason snipping tool in Windows inverts vertically mirrors the subs. Neh bother). So that's a relief in that the camera is not introducing these lines. So wonder whats causing that in my preprocessing routine? I am using the preprocessing script in PI 1.8 RC7. Exploration required there me thinks.

John, I do the histogram stretch then do a save as jpeg....? But it saves it as a linear image and not as a stretched one so appears as black with a few stars in a graphics package.... :confused:

LUM

post-16295-0-11134100-1376577384_thumb.j

RED

post-16295-0-66909600-1376577409_thumb.j

Edited by kirkster501
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These vertical lines - I have seen them before on my 460EX processed in Pixinsight. The ONLY way I found to dispense with them was to dispense with bias frames. I now dither and use flats and no more lines. They did my head in and I was mighty annoyed I couldn't get to the bottom of them. But I've got a work around and no one has mentioned my lack of bias frames!

Have you used bias frames?

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Yes Sara, I did use BIAS frames, taken at 0.001s. And my BIAS frames DO show this line effect. Thats not good is it!

The camera produces the BIAS like that - they show up as such in FITS liberator. So its nothing to do with PIXinsight - it's a camera issue.

Edited by kirkster501
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As I said Steve, I never got to the bottom of it. I found it whether I used bias frames taken in Artemis or Maxim. I asked on the PI forum, and never got to the bottom of it there either. This is an example of the bias frame stretched and then how it impacted on the image. I was initially annoyed that I couldn't use bias frames, but it really doesn't seem to give me an issue.

Maybe drop a line to Atik - I never got any joy from them either!!!

Sorry, that's not helped has it?

post-5681-0-45766300-1376581326_thumb.jp

Edited by swag72
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Here is my BIAS as well. It could be an hardware issue I think. Maybe one to contact ATIK about. Lets see what the experts on here think first.... Wonmder if its soemthign to do with Power? Are you connected to PSU or to a battery? What about you Martin and Gina? What firmware are you on guys?

post-16295-0-15356500-1376581493_thumb.j

EDIT: Every expert in the imaging universe uses BIAS. I believe we should be using them in accordance with every best practise.

Edited by kirkster501
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A bias can normally replace darks on a Sony CCD, so I'd be very keen to get that to work. I'll follow this with interest.

That is NOT what a bias should look like....

/Jesper

Edited by Jessun
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No USB hub in use, the EFW and 460 connect into separate ports direct into the PC. I am going to take the BIAS frames again tomorrow and see what happens. The one I posted here I took at room temp and 12v battery was fully charged.

Sent from my iPhone using Tapatalk

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Hi Steve,

Nice to see you imaging at last. I know you're having teething problems we ALL do.

I am confident you will get to the bottom of it and transform those lovely images.

Regards colour matching, as you have the IDAS filter in front of your LRGB filters you will

have imparted a colour "tint" that you may have to rectify. I suggest reading up on colour matching

your filters to a GV2 star.

cheers

Steve

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I have tried cooling the sensor and then taking BIAS. This is what I now get - auto-stretched by Artemis. This looks a little better to me..... However, this implies that BIAS frames are temperature dependent and I did not think that was the case? Without cooling I get the same BIAS as above, even with different Battery, Computer and cables. Maybe cooling then getting the temp is the solution here.

post-16295-0-91925800-1376646595_thumb.j

Edited by kirkster501
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I have tried cooling the sensor and then taking BIAS. This is what I now get - auto-stretched by Artemis. This looks a little better to me..... However, this implies that BIAS frames are temperature dependent and I did not think that was the case? Without cooling I get the same BIAS as above, even with different Battery, Computer and cables. Maybe cooling then getting the temp is the solution here.

I thought that temperature was important as it would affect the noise level of the chip? I always do the bias at the same temperature as the lights. They only take a minute of two to take a load so there's no great problem with creating more.

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Hi Steve, just checking you need to use the histogram transformation tool to stretch your images in PIxinsight, this will turn it from linear to stretched. Screen transfer does not change the data it remains linear.

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Just a thought, but Artemis has a button for inverting the image. I never touch it because you then have to remember to invert the calibration files. I don't think this is an issue here but if ever you find your bias/darks are murdering your images, this can be the reason. We had it here this week when the image got itself inverted by a false click somewhere along the line.

Stacking in PI seems to be difficult since I know several people who've found themselves getting it wrong at first. For a comparison you could always try downloading the trial AstroArt 5 to see if their very simple and fast system made any difference.

On colour balance I find Pixinsight literally infallible. Just ABE or DBE on subtraction mode seem to 'just do it.' SCNR green is usually needed on my data as well.

Nice to see you out and about! You've done better than I did at first.

Olly

Edited by ollypenrice
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