Just checking in...

[Scott Kuchma]

Hello Peter ,

Just checking in as I haven't seen or heard anything from you in a while . Still safe and of good health ?

If you haven't seen the two most recent Videos from James Lamb's Site , I think you may find them of interest .He's been doing some Software writing as well .

Also , a question about your M31 Andromeda Galaxy Image on your Web Site . When the Image appears on my Monitor it has a "green" cast to it . Is this what you see at your end ? My Monitor is calibrated and I've rechecked everything and it does seem like the only Image with that hue . Just curious .

Cheers ,

Scott............

[wols...@gmail.com]

Scott,

Display calibration is a bit of swamp.  I ended up looking at how my pictures look on my Samsung tablet.  I use a Dell Laptop with a 2nd monitor.  The images look different on the two monitors and I have never been able to get them to look the same. I also use the following link http://www.astrosurf.com/re/monitor_calibration.html   I do know that I am struggling with taking good FLAT frames.  One of the issues with poor quality FLATs is an increased risk of colour cast in your astrophotos.

I haven't noticed a green cast.  When I process with Startools I tell the colour module to get rid of green so I don't know what to tell you.  Another trick I use is to go to a professional astrophotographers website and look at his photos.  If they look good I figure that the monitor is set-up ok. I typically use https://astrodoc.ca/  Ron Brecher is very accomplished and has a great set-up.  He has given talks at my local astronomy group meetings.

Peter

P.S.  I just finished CaLIGHTs version 3.1.3 and will be releasing it this week.  Lots of changes and even more that for this release I have hidden from view because I want to think about them for a while.  

I will be switching gears after that because QHY has released new software for my QHY294C and I need to regenerate my DARK libraries for -10C. They also claim some of the things I have been nagging them about are finally fixed so I will be testing.  I am also struggling with FLATs and filters.  Some weird things going on that I haven't figured out.  I also ordered a light table from Amazon.  

https://www.amazon.ca/Diamond-Painting-Tracing-lightbox-sketching/dp/B08LV43CM2

Eventually I will figure out what's the best solution for FLATs with filters.  I like this light table approach because I will be able to take the flats before I start imaging which, for me, will be a big time saver.  I am also taking a close look at the twilight FLATs I have taken this year.  Everything is on the table right now.

[Scott Kuchma]

Hello Peter ,

Interesting . John M. had mentioned a while ago that the Images he was posting to a Server looked much different than the ones on his PC . I saw the same thing when I was linked in to his Images . Can't remember what the cause or fix was . Something about changing the bit depth and colorspace I think .

Funny story , I met Ron Brecher at a Seminar at KW Telescopes in Kitchener last year around the first week of March . We talked briefly about Monitor Calibrations and what he used . He said he was using the Datacolor SpyderX Pro System . This was the Seminar where they were handing out copies of your paper on CaLIGHTs . I was intrigued as it seemed to offer an easier method to do Image Calibrations so I took a copy and the rest is history as they say . LOL.

As to your Andromeda Image , when you go to your Website from your PC , does the Image look the same as it does if you just open the Image from a Directory ? All your other Images are perfect , no cast or hue changes . Just M31 .

I'm being picky here but you say above that you'll be able to "take the flats before I start imaging..." ? Really ? How will you be certain of focus or orientation ? I've always done mine *after* an Imaging Session . Interesting .

Scott................

[wols...@gmail.com]

Scott,

I take it that you didn't go ahead a buy a Datacolor SpyderX Pro System.  Ron had mentioned the same device when he talked at the Hamilton Amateur Astronomers meeting.  He is deep sneakers into astrophotography and he makes a strong argument for Pixinsight and monitor calibration. To me, astrophotography is a hobby where the majority of people who will look at my photos will be using a cell phone, tablet or a consumer monitor. My laptop screen and my 2nd monitor could not be more different.  I may invest in a quality monitor...someday.

I did compare the website image to an image on my hard drive.  They look identical...certainly no color cast issues.

Another aspect of this "swamp" is the capabilities of the graphics card.  I just checked mine and for my 2nd monitor it has 3 setting for "Quantization Range" (Default, Limited and Full).  I have been using Default.  Limited and Default appear to be the same.  Switching to Full causes a much darker black which will certainly affect how I develop my images.  I suspect the same variability applies to most people visiting my website.

Another aspect of this "swamp" is the color setting of your monitor.  I can choose a color temperature of 9300K, 6500K and sRGB.  I have been choosing 6500K but I suspect I should be using sRGB.  The color differences between 6500K and sRGB are visible but not dominant.

Some experts have stated that the background lighting in the room affects the image but as some point you have to draw a line.

Regardless of what settings I use I don't see a green color cast showing up in Andromeda.  Is the green color cast close to the bright centre of the galaxy or in the surrounding sky background? 

Is the very centre of the galaxy blown out?  My original settings only showed a very small dot blown out.  When I switched to sRGB it became a lot larger and very dominant. I need to calibrate the monitor for these new settings.

Taking FLATs before image...

I have always used the CaLIGHTs LIGHTTABLE feature to take my FLATs.  Getting everything together to do this the next morning is a real hassle.  I have looked for a lightweight monitor that I could place on the telescope while it sits on the mount but I haven't moved to that approach.  Setting the telescope on the kitchen table and aligning it to my 2nd monitor and cabling it up to run the astrocam is a real pain.

I'm hoping to use the light table I bought from Amazon which is USB powered.  I typically use the same telescope for several nights so focus is always very close.  When I do use my telescope for the first time I can preset the focuser barrel using a ruler on my refractor.  For the EdgeHD I typically using my D5300 to focus on a distant object to get it close.  Then I change over to the astrocam which is very close to a parfocal arrangement.

The main benefit is that I can take FLATs once I have my set-up assembled.  I will position the telescope pointing straight upwards and place the light table on the objective.  A few minutes later I have my FLATs.  I won't know if this works until I get a change to try it out. Obviously if I decide to rotate the camera then the FLATs need to be redone.

I have experimented with twilight FLATs. Getting reasonable red, green and blue exposures is not possible...especially for narrowband imaging. I will be continuing to surf the web for discussions regarding taking FLATs.

I am struggling with taking FLATs right now and it's causing lots of color cast issues.  Startools does a pretty good job of eliminating it but some images just can't be saved.

Peter

[Scott Kuchma]

Hi Peter ,

No , I didn't buy that Datacolor Product . I have an old Spyder-3 I used when I was doing Projector Calibrations as a Hobby but the Device is now uncalibrated and the Software and Drivers have expired . It's not worth the expense to update it .

I am running my Monitor in sRGB at 6500K as are all the other Displays in the house . Different Graphics cards and drivers for sure . I've tried various PC's and Web Browsers and since I'm seeing the same thing on all , including my iPad , I have concluded it must be my eyes . LOL . They can't all be showing the same thing ? The olive green cast I see is in the dark dust band behind the core of M31 . Just for giggles I'm attaching a Snip I took of that section from your Site . If this looks normal to you on your end then my days as an Astrophotographer are doomed . LOL . I'll bet that on your end this has a warm golden cast to the core and surrounding area ?

Let me know .

Scott............

[wols...@gmail.com]

Scott,

I think you have a value argument...your eyes are probably working just fine.  There is an olive green colour cast.  I'm going to assume that by bias comes from having processed the image which always burns up lots of time...sort of a "good enuf" mentality takes over that causes me to ignore imperfections.  Startools says that the sky background is neutral which is what I normally look for.  Processing the image with a mask would allow me to tweek the core without colour washing the entire photo.  This may be an artifact of the issues I am having with FLATs.  Andromeda is a very bright DSO and that may be why the colour cast is visible.  I have always found that Andromeda is tough to process.  I will try to reduce the green cast and replace this image.  I will let you know when I get that done. 

Peter

[Scott Kuchma]

Hi Peter ,

OK , but the question now is why do you see it in the Image I posted and not from your Hard Drive or when you looked at your own Web Site ? I swear Tech is going to be the death of us all .LOL .

I have to admit , I'd love to be able to run your DSS Stacked FITS File through the Process I use , SiriL + Sharpen Ai + DeNoise Ai + Fastone , to see what I could get with a high Data Image . We have talked about Image Processing before .

Remember , we're all here to help each other in this "Hobby" . Everything is important and useful .

Scott...............

[wols...@gmail.com]

Scott,

I think is more like "Now that you point it out...it does look green.  The image is the same...I just didn't pick up on the colour of the dark dust lanes.  I think the issue with my Andromeda image are that my FLATs are not good.  I am really struggling with FLATs. The other issue is that my house is just south of Hamilton and on Nov 7th, 2020 I was imaging Andromeda with the telescope pointed north...directly over Hamilton so the light polution was very bad. Typical pixel values corresponding to the sky background were hovering around 3000 to 5000.  When I image up north the sky background would have been 100 to 200. I think that lots of light polution compounds problems with bad FLATs.  I struggle getting Startools to "wipe" the data and eliminate the gradients.

Your welcome to take a crack at it   http://home.quickclic.net/~pmwolsley/Autosave011.zip

Hopefully you see the issues with the colour cast of the sky background

Peter

[wols...@gmail.com]

Opps,

Don't bother download the file.  It's not the correct version.  Give me until tomorrow to figure out what's what.  I have 12 different versions of this stacked image and some are terrible.  There will be 36 images stacked in the correct version.  The one I made available used only 6 images...don't ask why...I test a lot of different things trying to learn what corrects specific issues.

Peter

[Scott Kuchma]

Hi Peter ,

Yup , I was just reading the "not available" download message when your Email came in . Good timing ! No rush on this of course but I am getting desperate for something to do . LOL .

Have you had a chance yet to take a look at James Lamb's last two Videos ? He's written some Code with Python to sort Targets based on time of year and his location , which is editable , and with Data taken from Stellarium .

It is available for download to try . I asked if it could include Magnitude values as I really can't/won't Image anything fainter than mag 9 as I can't expose too long...yet . We'll see if he can include it .

Still trying to fathom the technique for inserting my own skyline into Stellarium . That would be of use to me . Still learning .

Scott...........

[wols...@gmail.com]

Ok. I did some research. Startools maintains a log file that details when I create jpg or tiff files...which is when I have a finished product.  I found Andromeda and I found that autosave001.fts is the one to use.  I put it into a file called Andromeda.zip

Here is the link

 http://home.quickclic.net/~pmwolsley/Andromeda.zip

Enjoy

Peter

Let me know when you have downloaded...I want to blow it away

I will check out James Lamb's videos

[Scott Kuchma]

Hi Peter ,

Sorry , still getting "404 File not found" Message . I've tried clicking the Hyperlink and cut and paste into the Browser URL . No go .

Maybe I was too tardy in downloading and you've already deleted it ?

Scott............

[wols...@gmail.com]

Dang hyperlinks  I get caught by this all the time.  You can make the hyperlink say anything you want.  The actual web address that it link to can be completely different.  Here is the correct link

 http://home.quickclic.net/~pmwolsley/Andromeda.zip

[Scott Kuchma]

HaHa , no worries . Got it this time . Now the fun begins .

Scott..........

[wols...@gmail.com]

Scott,

I have made another version of Andromeda and posted it to my website.  The green is gone. It could be better...but sometimes you need to just walk away.  A big advantage with Andromeda is that it is very bright.  It's dominance tends to minimize colour cast issues.

Peter

On Tuesday, March 2, 2021 at 1:22:34 PM UTC-5 wols...@gmail.com wrote:

[wols...@gmail.com]

Ok Scott...I am going to delete it.

Peter

[Scott Kuchma]

Hi Peter ,

Just noticed that Image , very nice . I went back to check on which Scope you had used for the Imaging . Couldn't remember if you had the 0.7X Reducer or were using something else . The BK80ED I see .

Scott...........

[Scott Kuchma]

Hi Peter ,

Well , so this is what it's like to work with good Data eh ? LOL . Wow , lots of Stars and Detail in the Image . I've done a quick run through just to see how all that fine Data reacts to my Processing steps .

I see some obvious things but all of this is down to personal taste in the end . My new "technique" is to halve any Auto applied Setting as the recommended Settings seem to be too much in a lot of cases .

Biggest observation is that I seem to have lost a good portion of the Galaxy's "glow" , especially to the left side , so I will go back and start again and concentrate on where that was *removed* .

It's good to have examples pulled up from other Sources that you can open up next to your Work to compare the Processing steps . Here's what my first run through looks like...

Scott..........

[Scott Kuchma]

Hi Peter ,

OK , one more run through with the exclusion of the Asinh Transformation in SiriL . I can always get a better background in FastStone by using the Gamma Control . It's ..."different" but I'm not sure if it is ..."better" .

There's a slight colour cast towards magenta in the left side of M31 . This was only a value of +3 on the Red in FastStone . Very touchy . A million possible Image outcomes . This should all be more automated and easier .

Honestly , if this was my Data , to go with this particular Processing , I'd be opening some fine wine and toasting the Gods of Astrophotography . LOL .

Thanks for letting me play with your M31 Data . This has inspired me to pursue some additions to my Astro Equipment in an effort to improve my Data Collection .

Cheers ,

Scott..............

[Scott Kuchma]

OK , one last poke at this Target . I am learning a few new things in my approach to Processing by being able to work on this Image so , thanks again Peter for the opportunity .

Because of the bright Core I'll assume this Image would benefit from being able to use a Mask to separate the Galaxy Processing from the Background . A universal process here may not be the best .

Sadly , SiriL does not offer a Masking Option at this time and it is not mentioned in their planned Release Notes for the upcoming full 1.00.00 version .

After talking with John M. last night I decided to try changing the "areas" used by SiriL in performing the Colour Calibration . I picked an area of clean background that did include a spattering of Stars and then picked the lower left side of M31 as the bright area for the calculation . Autostretch still seems to do a better job at the Histogram than my manual attempts . No Asinh this time either . Full Colour Saturation though .Then into Faststone before either of the Topaz Ai Products . Minor tweaks with the Gamma control , a +3/100 on the Red and a pinch of Contrast adjustment .  Topaz did not alter the Image by much and chose Focus from the Sharpen Module and Ai Clear from DeNoise .

I did find something I have to be very wary of when using the Topaz Products . It's my viewing position in front of my Monitor . I thought I was seeing non-circular Stars on some of the Comparison Viewing Panes which was causing me to pick the wrong Ai Mode . Upon closer inspection , with my coke-bottle glasses removed , they all looked fine . It also depended on my up/down and left/right position to the Image on Screen . Something I've got to be careful of in the future . Most of the Previews were quite good afterall . LOL .

So here is attempt #3 . It appears to have a bit of a Gradient top left which did not appear until near the end of the Processing . I'll have to have another look at where that came in and why it did not process out .

Thanks again for sharing .

Scott............

[wols...@gmail.com]

Scott,

Oval Stars...I have the same issue...my glasses warp stars unless I get right up to the screen...very frustrating.  I have very good polar alignment and guiding and the BK80ED exhibits virtually zero differential flexure...out-of-round stars is not much of an issue for me...thankfully.  It is satisfying seeing the detail in the dust lanes.  I really like pulling out color in the stars.  I use a starmask with the Startools color module. I tweek the entire image without a mask initially and then I mask rerun the color module with the mask so I can tweek the stars.  Then I use the shrink mode in it's dim mode to tame the stars.  It's very effective and if done right you end up with stars that have a real ball-light appearance where the light gradient falls off in a very leasing manner.

I pulled up the sky background too much in my andromeda.  I may go back and tone the background down.  It takes hours to develop these images and you need to be in the right mood and have the time available.  I notice the three dots at the bottom of my post.  Google Groups automatically doesn't show you everything in your posts that is repeated.  Your posts are getting pretty big because every image is included.  Check some of your post to see what I mean.  I went ahead and deleted all of the old stuff in this post...just to clean things up.

Peter