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Peter in Reno
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: Peter in Reno]
      #5523657 - 11/16/12 11:45 PM Attachment (28 downloads)

Hi Dave,

It's me again. This process includes Ha. The image appears more bluish and the red spots appear redder. Processing is not an exact science. It's mostly eyeballing and estimation. In other words, it's always difficult to re-process the same data and get same results. For example, it's easy to over or under stretch and get different results.

I think Ha is under exposed especially for a galaxy containing very few Ha data. In the future, I suggest exposing close to 30 minutes for any narrow band especially on a galaxy. The background is so low and can be lower than read noise and that can make it difficult to process. I checked the ADU value of the background of Ha and the typical value is at a whopping low value of between 1 and 30 which is most likely lower than the read noise in your camera. Normally you want the background to dominate the read noise so that processing is easier. The solution would be to expose long enough for the background to dominate the read noise of your camera.

The minimum ADU for your ALL of your LRGB and Ha is -33333 like your Blue image of Bubble Nebula. I think I know why. The black borders around the image due to images taken on different nights or dithering and stacking the subs that results black borders. The black borders reads at -33333 which means the images need to be cropped to exclude the black borders. Bottom line there was nothing wrong with the blue image from Bubble Nebula in the first place, it's how the software stacked the subs and naturally resulted small black borders that caused the software to think the minimum value at the black border to read at -33333. So finally problem solved for this.

Peter


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SL63 AMG
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: Peter in Reno]
      #5523664 - 11/16/12 11:54 PM

Aha, so the mystery is solved. Great detective work.

Should I crop the images just before I stack them, or after?

Are you going to finish processing the bubble now that the blue data is ok?

I am going to attempt to process my NGC 1579 data this weekend. After tonight, I'll have about 5 hours of luminance data and about 1.5 hours each of RGB.

The data looks great.


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Peter in Reno
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: SL63 AMG]
      #5523688 - 11/17/12 12:10 AM

No, it's better to stack the subs first before cropping. Don't bother cropping after stacking if you want others to process your images. Let others crop according to their preference. It's better this way since all images you provided are already registered and stars are well aligned. It's important to crop after stacking or RGB combination to remove any black borders so that color calibration is done correctly.

I will look at your Bubble maybe tomorrow.

Thanks again for providing excellent data.

Just follow Harry's great PixInsight tutorials when processing NGC 1579. That's how I learned it. PixInsight also has a very good tutorial on LRGB processing at their web site. Harry's tutorial has two or three different LRGB processing tutorials and all of them are done a little differently. So it depends on the DSO you capture.

Have you process M33 yet?

Peter


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SL63 AMG
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: Peter in Reno]
      #5523739 - 11/17/12 01:00 AM

No, I have not processed M33 with PixInsight. The one I did last year was processed with CCDStack and Photoshop according to Adam Block's video's.

I have tried to follow both Harry's tutorials and the PixInsight tutorial and I always seem to get lost doing Histogram Transformation when I am supposed to drop the STF onto the HT tool. My histogram on the bottom Window never looks like their's. Instead of a sharp peak on the left hand edge, minae are always flat like a soft bump in the road.

I can't figure it out and quite frankly, I'm never going to be able to process images well until someone sits down with me and shows me how to do it.

I am to right brained for anything artistic. I see everything in grayscale, binary, 1's and 0's, black and white.

I have no artistic talent whatsoever.

I am extremely technical and I am an excellent troubleshooter. I even have experience writing software and designing hardware, but I can't draw, I can't envision art or colors well in my mind. My wife tyhinks it's kind of funny.

She keeps telling me... just do what you do honey... get the data and have fun!


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Peter in Reno
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: SL63 AMG]
      #5523752 - 11/17/12 01:13 AM

Hi Dave,

I never drop the STF on HT tool. I don't recall seeing Harry's video doing that but I have seen PixInsight video do that. When I am ready to use HT, I reset the STF so that the image is no longer "stretched" and use HT tool to stretch the image. I can't explain in words but I use HT in iterative method by stretching a little bit and apply to the image and repeat until the image looks reasonably good.

I am also a software/hardware engineer but never an artist. It took me a while to figure out how graphics works. Once you get the hang of it, it will get pretty easy.

Peter


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blueman
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: Peter in Reno]
      #5523764 - 11/17/12 01:25 AM

Indeed, 2x2 binned RGB will not work as well for making Synthetic Luminance.
I only use 1x1 binning for RGB. I did try some 2x2 a few times, but I found that the data just was not as good as 1x1 for my purpose. I just am not a fan of 2x2 and then adding it to 1x1 luminace data.
Blueman

Quote:

Hi Dave,

Yes, it was for testing purpose to compare "real" Luminance with "Synthetic" Luminance. To an average person, it was difficult to tell the difference but when I was comparing the two by blinking in between the two, "real" Luminance was the winner.

It's possible if the original RGB subs were capture in binned 1x1, the result would have been different but you would have to capture significantly more RGB subs to nearly match with "real" Luminance. That possibly explains why Synthetic Luminance was not as sharp due to RGB being captured in binned 2x2.

Peter




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rigel123
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: SL63 AMG]
      #5523792 - 11/17/12 02:01 AM

Quote:

It's too bad you don't have clear enough skies to capture the luminance data. I think it is most important.

I remember something about Adam Block showing that one could take RGB data and apply a heavy gaussian blur to it and when layered with the crisp 1x1 binned luminance data would produce a beautiful color image.






That is how I work on most of my images. Most of the time goes to luminance and less time on RGB which I blur pretty heavily and then add the Luminance to it. In narrowband I typically follow JP Metsavainio's Tone Mapping procedure where you remove the stars in the individual channels, stretch and blur the data, combine them for your chrominance, and then add the Luminance to that. It's great for keeping noise down in an image.


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SL63 AMG
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: rigel123]
      #5523827 - 11/17/12 03:28 AM

Ok Warren, you have been selected to come to Arizona and teach me.

Free Bed and Breakfast and use of the 18" DOB.


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StevenMx
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: SL63 AMG]
      #5524012 - 11/17/12 09:30 AM

Hi Dave,
I am with Peter Reno, I don’t usually use auto STF except to get a quick look at a linear image. When I use it I usually deselect the linked channels. I have dropped the STF process onto HST but rarely do I leave it at that setting before applying it. I do my best to manipulate the individual channels to keep the colors balanced “flat” before applying. Otherwise you end up with an unnatural (in relation to the RGBs) color in the end. If your histogram flattens “like a soft bump in the road” it might be because you forgot to disable STF before applying it to HST. You asked me about gradients, not sure I can answer that one. You have much more experience imaging than I do. And I only have experience in one shot color ccd.
Btw...my version of your M33 got image of the day today on AstroBin. That’s kind of exciting, I’ll take it!!


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pfile
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: StevenMx]
      #5524277 - 11/17/12 12:18 PM

sometimes with the black bars left in the image, or because of a lot of background noise, the histogram appears empty. this is because there's a zillion pixels at 0 and the huge spike at 0 is hiding the rest of the data - the scale of the histogram displays has been adjusted to show the spike, but then you can't see the "real" data.

either you can crop, or do some background noise reduction, or just use the histogram zoom tools. there are 4 little boxes with "1"s in them between the bottom and top histogram displays. they control the horizontal and vertical zoom for the bottom and top displays. i've had to zoom in 500-600x sometimes because of the noise/black bar spike!


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Peter in Reno
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: pfile]
      #5526739 - 11/18/12 07:59 PM

Dave,

In case you didn't see it, I posted my process of Bubble Nebula at your older thread at:

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5475418/page...

I also explained why I was wrong when I said that there's nothing wrong with the blue image of Bubble Nebula.

Peter

Edited by Peter in Reno (11/20/12 10:25 AM)


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stephen63
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: Peter in Reno]
      #5529303 - 11/20/12 02:04 AM

Dave,
My latest attempt at your data. I use a laptop to process everything so perhaps that is the reason my images appear off. I have calibrated my monitor but who knows if its right. Typically, I download an image of the object from a reputable photographer, and bounce the color values against what I'm working on. In this case, I tried to match the colors of Robert Gendler's version of this image. Specifically, I tried to increase the detail of NGC 604.
As to your filter,
The left side of the galaxy that seems to be missing data is just that, a lack of star formation that is probably due to its interaction with another galaxy, perhaps, M31. Or, its a dust cloud. Either way, it has nothing to do with your filter position during capture.
I replaced your original with this.
http://www.flickr.com/photos/stephen63/8186277341/sizes/h/in/photostream/


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StevenMx
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: stephen63]
      #5530527 - 11/20/12 04:06 PM Attachment (12 downloads)

Hi Dave, here is an updated version without Decon artifacts.

Daves' Larger M33

Edited by StevenMx (11/20/12 04:09 PM)


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StevenMx
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: StevenMx]
      #5537322 - 11/24/12 02:26 PM Attachment (9 downloads)

Hi Dave, I started again from beginning using a couple different masks. This is my final version, hope you like it.
Daves' Larger M33


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manoss27
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: Peter in Reno]
      #6155920 - 10/24/13 04:47 PM

thank you for the files!!!!

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SL63 AMG
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: manoss27]
      #6159774 - 10/26/13 08:26 PM

You are quite welcome.

I'll post more soon. I am gathering lots of data on different objects with an RCOS 12.5" and 16803 chip.


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coinboy1
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: SL63 AMG]
      #6163148 - 10/28/13 06:48 PM

Yes thanks for the good data. I am trying my hand at some different processing software. This is very good practice for me.

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alpal
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Re: M33 - LRGBHa Data for Processing - No Copyright *DELETED* new [Re: coinboy1]
      #6163401 - 10/28/13 09:34 PM

Post deleted by alpal

Edited by alpal (10/28/13 10:14 PM)


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alpal
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: alpal]
      #6163754 - 10/29/13 12:15 AM Attachment (9 downloads)

Thanks Dave,
It's nice to get such wonderful data to work with.
I think Steve's version of larger M33 is the best so far.
This is my take on it after a stretch function x^1/5 in FITs Liberator & processing in PS.
I used ArcSin stretch for the core & blended with masks.
My aim was to try & bring out the faint areas without overexposing the brighter.
This was my 2nd go at it - I deleted the first one.

Larger version here:
http://www.flickr.com/photos/24719437@N03/10549703135/sizes/o/


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Joe F Gafford
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Re: M33 - LRGBHa Data for Processing - No Copyright new [Re: alpal]
      #6163809 - 10/29/13 12:52 AM Attachment (6 downloads)

Thanks for the tryout using another source than mine. Here's my submission. Maxim DL, CCD Soft, PS CS-6, Fits liberator.

Joe


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