New PIXINSIGHT Tool Released: Spectrophotometric Color Calibration (SPCC)

[@steveb.7593]

Dank deiner Ausführungen komme ich endlich weiter. Einfach Klasse beschrieben! Danke.

[@juliansanzdoctor9360]

Magnificent explanatory video. I don't see differences either, what I do see is the difficulty in obtaining identical results.

[@javaruck]

Excellent video! Once I got past the frustration of downloading the catalog I did manage to get the SPCC to work. To my eyes, I don't really see a difference versus PCC but at least I have bragging rights about doing color correction the right way.

[@viewintospace]

If you have 45mins and want to really know in every detail why it makes sense to use SPCC, watch the second part of Adam Blocks video - after that, you have no doubt anymore ;-) kzbin.info/www/bejne/rWnXl2CVnLp_irM

[@robertgrenader858]

Thank you from the bottom of my astrophotography heart, seriously. I was able to get, thanks to your video, PCC working. SPCC returned a DB not found error, and I will work on that.

[@viewintospace]

Most likely you made an error when registering the files in the Gaia process….

[@delmarvawx]

@@viewintospace I have the same issue as well. PCC will work fine but SPCC will get the DB error even after downloading the whole catalog for Gaia. They really should have left the search function alone. Just more of a pain to do this now

[@marcelomunoz84]

Excellent work. It has clarified the base for me and it is a good complement to the official Pixinsight article.

[@paulwhitmarsh]

Hi Thanks for posting this video, I missed seeing the email from Pixinsight so I was very confused when I looked at the very different Photometric calibration options. I'm downloading the Gaia data now. To answer the question on what the roman numerals represent. They describe the Luminosity class of the star, i.e. where it fits on an HR diagram. So I - Supergiants; II - Bright Giants; III - Giants; IV - Subgiants; V - Dwarfs (Main Sequence) Thanks again for the video, I'll be sure to subscribe and watch more.

[@dalep2842]

Thanks so much for doing this! You are correct things sure got changed and I was confused! This really helped me get back on track! Much apprciated!

Thank you! The trick of plate solving step did it! I was getting crazy with the error

[@philsimpson]

I have used this since yesterday and after stumbling a little on the requirement to platesolve I too can see no difference between SPCC and PCC, except when I changed the QE curve to my sensor where it fractionally lightened the overall background in the image, but all starts were treated the same.

[@xaviergaborit5174]

Hello, I thank you for your Tuto because you have just reassured me. I discovered just like you after the update of Pixinsight this new tool and I understood nothing but nothing with their explanatory link. I then did several tests on M42 and just like you I find no difference as we could have with the old tool that I liked because it was very easy to use. reassure me but I'm waiting for the rest to understand this new function better. To be continued. thank you.

[@yervantparnagian5999]

Great video on this process. Thanks for sharing your efforts. I'm seeing very slightly deeper reds with a bit blacker blacks with SPCC.

[@michaelring9547]

One hint for people using wbpp script: when you color combine your mono results you will loose your platesolving but there is a process called copycoordinates which helps you to copy the coordinates of one of your single platesolving frames to the combined picture.

[@T3kko]

Channel Combination and LRGB Combination both transfer the astrometric solution through provided the box is checked to enable it.

[@FAstroHD]

Your videos are fantastic mate, well done and thanks

[@markmuratore413]

I saw a difference with M33. The PCC had a slightly more red cast overall in the galaxy while with SPCC the galaxy was more white but I was still able to see the Ha regions. That was with a 294MC Pro OSC camera and a Baader Moon and Skyglow filter. I guess the results would depend on the target. Great video, thanks.

[@pacificsun4379]

Thanks!

[@thesummerhillstead2577]

Thanks for your excellent video!

[@timmoody7600]

Am I right that you run this on a linear image? You re-stretch after PCC and SPCC, so I assume what we are seeing is autostretch. Would also be nice to see detail on pre and post SPCC. In the video they look pretty similar.

[@viewintospace]

Yes, you absolutely have to run this on a linear image - same as you would have done with PCC. Now the difference is also similar to PCC - sometimes the difference is massive, sometimes minimal, depending on much your image differed from the color calibrated level. I think this can not be emphasised enough - SPCC is very similar than PCC from what it does and what the outcome is - but it is much more reliable. much more accurate and much less prone to error. But you only really see that in cases where PCC would have failed.....

[@fernandolonde3472]

I think the QE Curve is based on your camera back-illuminated CMOS image sensor for example I use ASI2600MC with IMX571 backlit sensor

[@viewintospace]

Thanks - that was helpful!

[@lenjones2268]

Thankyou Sascha for this most helpful video, and boy did we need it!!!!, just probably a silly question, but for Narrowband Ha/OIII and SII do I just use the Green and Blue wavelengths at the OIII setting of 500.70 for Blue and Green with my filter bandwidth of course???

[@viewintospace]

Exactly!

[@YTMegiddo]

I've yet to see really image improvement with doing these photometic calibrations. I'm too lazy to work at this and only see the tiniest improvement. But that might just be me. Good video!!!

[@alanbruce2356]

May I ask what process have been completed up to the point of the start of this video, such as stretch, denoise, linear or non etc? thank you for this video. :)

[@viewintospace]

I would recommend to do SPCC in the linear phase. I usually do only Dynamic Crop and DBE before I color calibrate. You can see a full workflow in my recent RGB tutorial.

[@johndavis9641]

Quite frustrating that they made such a significant change in the behavior of PCC without any backwards compatibility... I don't use the batch processing script for my pre-processing, so now I'm stuck with the plate solving step that you described. Very poor customer support IMO. Thanks for your clear explanation of the changes and the need for the plate solving before using PCC or SPCC

[@viewintospace]

I will release today or tomorrow a more in-depth tutorial on the image solver…,,

[@Mr77pro]

Great vid...thanks! I don't think many of us are doing science with our images, so "accurate" color is not really a goal and any "color calibration" done to our images usually gets tweaked to personal taste anyways...especially with NB imaging.

[@monteroder2708]

Sasha...have you heard of any issues getting this to run because an image has been cropped? Sometimes getting an error message that it failed and was wondering if cropping has anything to do with it. I do have Astrometric solution checked in WBPP.

[@viewintospace]

Yes, cropping creates issue as it deletes the astrometric solution. So once you crop, you need to run Image Solver before SPCC. Except you use the AutoCrop function of WBPP.

[@monteroder2708]

@@viewintospace Sascha...thank you for the response. I do have autocrop checked when I initially run wbpp. Are you saying t hat I still need image Solver even though I'm already using that function in wbpp?

[@viewintospace]

@@monteroder2708 No, if you use Autocrop it should be solved correctly and ready for SPCC.

[@monteroder2708]

@@viewintospace thanks Sascha. I agree with you however it still gives me issues. I'll continue to try and work with it.

[@astrodad656]

After getting the Astrometry and PCC completed the SCC failed. It states that the database files for the Gaia Catalog are not available or the XPSD server is not properly configured. What am I missing here?? Thnx

[@viewintospace]

Did you download the /SP versions? If yes, open the Gaia process again and ensure that are displayed in the /SP section.

[@astrodad656]

@@viewintospace Yes, downloadded the large 3/SP files. And the Astrometry worked. But it looks like it is searching my C drive for the Gaia [I installed Gaia on my "K" drive]. Is there a way to direct it to the K drive? From the Process Console: ** Error: Database files not available for the Gaia DR3/SP catalog, or the XPSD server is not properly configured. Reading swap files... 2088.810 MiB/s

[@astrodad656]

I found that if you alter the solved image with DBE or crop you have to re-plate solve.

[@viewintospace]

@@astrodad656 Yes, that is true. Always solve right before SPCC

[@TheOriginalTommo]

Question.... for anyone willing to answer! If I have done SPCC on OSC (ZWO 533MC Pro) data, should I still need to do SCNR, or should SCNR be done first, or not needed at all???? Am looking at data of the Veil at 200mm (linear but STF'd on-screen) it still looks quite green after SPCC without SCNR applied at any point. Interested to know other's experiences.....

[@viewintospace]

I personally use it after SPCC to get the last bit of annoying green out of it.....

[@johnseniura8026]

I've managed to download the small set, but I'm getting an error that says the sample size is too small. Is this because I need the full set? Or is there some setting I need to change?

[@viewintospace]

Should you download the larger set? Yes, you should - because PI recommends it in their SPCC manual. You do not need to do it on your primary hard drive, and external one is fine. Will it help you with your issue? Maybe, but most likely not.... ;-) What might help you is the "Signal Evaluation" Section. Play with these settings -e.g. increase the detection scales, increase noise reduction and so on.... It's a lottery but maybe you win! Good luck!

[@dudleyjohn06]

@@viewintospace Thanks for your videos. They've been very helpful to me. I've managed to download 4 of the files, so far. The download is excruciatingly slow and stops frequently. I did get SPCC to work, finally, even with only the limited set. I used your hint about fitsheader, then did the image solver. I wasn't doing that correctly.

[@mikeblank9837]

I keep getting the same error when trying to do this: Error: Insufficient data: only 0 sample(s) are available; at least 5 are required. Any thoughts?

[@viewintospace]

Sure, do you have any of the below: - Egg shaped stars - blurry stars - only few stars - strong noise / low S/N ratio - high focal length All of that and especially a combination of that can lead to the above. Two options: a) Play with the settings in the section signal evaluation in the SPCC - if you play long enough you might find the combination who give to the five needed stars b) Realise that SPCC is nice but not ultimately essential and use the regular color calibration.

[@magedsyehia]

What if my DSLR camera is not included in the sensors list?

[@viewintospace]

Just select the Ideal QE curve

[@brentonrasheed384]

Hey Sascha , any idea what’s happening here? I’m getting this error message with SPCC - after I’ve run image solver. Have linked the down loads from PI. *** Error: Invalid Gaia DR3/SP XPSD server execution: Couldn't retrieve a valid spectrum wavelength table. Reading swap files... 10200.346 MiB/s

[@viewintospace]

So it worked before but not not anymore? Check if your Gaia files are still there, no change in directory names, no external HD removed, no files deleted in error and also go into the Gaia process and check if the whole set is still displayed there....

[@brentonrasheed384]

@@viewintospace yes it worked fine - but had a bit of a mishap with iCloud and had to redirect PI to look for the data base on an external SSD Drive which I think you said we could do. They are on the SSD drive. But I get this message I sent you - even if I go to Astrometry and relink the datas base. So, I'll try moving the data base - but wondering if the actual data base was corrupted somehow. Maybe I download again? l'll try moving it first

[@viewintospace]

You simply have in the Gaia process to reselect the files in there new location and all will be fine again.

[@brentonrasheed384]

@@viewintospace -that’s logical, but not working when redirected to the SSD drive. There’s another issue I think. iCloud removed files from my drive and it’s mucked up a lot of other things too. I’ll sort it. Thanks for the advice.

[@indysbike3014]

Once more this shows that I did the right thing by investing my time in Siril. Siril also does PCC and with less complexity.

[@viewintospace]

While I fully agree with you that PI in general and SPCC specifically is rather complex, from my perspective it still pays off given the vast possibilities that you have with PI and unique power of certain processes.

[@AstroPixUK]

Really good video, thanks. I conducted the plate solver as i stacked in APP. That went fine, however when i run SPCC i get this error message. Any ideas? * Extracting PSF signal samples *** Error: No stars found (channel 0)

[@viewintospace]

In such cases you have to start fiddling around in the "Signal Evaluation" section. Try some stuff and it might help - I know that is very vague but to me it really feels sometimes a bit random....

[@scottbadger4107]

FWIW, I don't see any real color difference either, but the SPCC looks like it has a bit more contrast than the PCC image. in the close-up you show, the dark area extending into the upper left-hand corner looks just a little darker. Regarding the lack of built in plate-solving for both SPCC and PCC now, the PI developers have commented that it was 'poor design' to make plate-solving part of PCC originally, but it would be helpful if there was some explanation as to why.....

[@viewintospace]

As much respect I have for the PI developers from what they achieved from a functionality point of view, this company should definitely invest in a dedicated UX expert..... Anyway, the only real reason I see is that when you combine processes it is hard to judge what the cause of an issue is - e.g. did the plate solving fail or the photometry? But then to be consistent you would also have to erase the Background Neutralisation part within the (S)PCC process.....

[@scottbadger4107]

@@viewintospace On the bright side, if SPCC really was substantially different/better, think of all the images we'd feel the need to re-process.....

[@scottbadger4107]

@@viewintospace In a PI forum thread, Juan Conejero made the point that PI is intended to be modular and combining processes breaks that design philosophy, but as you point out why is Background Neutralization still included, especially when it's a process that gives the user more latitude of control than a simply perfunctory step like plate-solving?.....

[@Spaced_Out_Bill]

I'm feeling frustrated 😄 I don't have the tool yet. I'm on the latest version of PI too.

[@viewintospace]

Check the version number - most likely you are not on the newest version but the update function failed - was with me the case. In such a situation you need to download the newest version from the PixInsight homepage, deinstall the old version and then install the new one.

[@TheoChannel100]

@@viewintospace That means I have to setup my GPU support for StarXTerminator again too :(((

[@viewintospace]

@@TheoChannel100 In my case it restored everything automatically

[@TheoChannel100]

For the SPCC white reference Star classification, see : en.wikipedia.org/wiki/Stellar_classification

[@viewintospace]

Thanks!

[@ScoobyJoobyJew]

The SPCC image is quite obviously more vibrant on my TV in your side by side comparison. Definitely not the same results.

[@viewintospace]

That is a very real issue - you might "calibrate" your pic as long as you want, but as long as the screen is not calibrated, it might still look much different. This is influenced by screen type, screen tone, contrast and brightness settings....

[@taishasteep7398]

Does this change your easy 10 steps?

[@viewintospace]

Yes, in all workflows where PCC is mentioned, now SPCC should be applied is also requires the image solving as described in this video

[@SinCityDarkKnight]

Making me download 60gb of sky Atlas gaia files, nonetheless at 3mbps (I have gigabit f.o.) with the files failing every 15 seconds sent me into the roidiest of roid rages this afternoon

[@SunJao]

You only need to d/l the files up to the limiting magnitude of you scope objective diameter. For example, I only need the 1st 3 files for a C11.

[@nikaxstrophotography]

They made it worse in my opinion with the extra fudging around using scripts etc to plate solve

[@viewintospace]

Agree 100%

[@donsinger1]

I agree 300% but you did a teriffic job explaining pitfalls to avoid and how to use the new tool. Great job and I am now a new Subscriber 👏

[@addos999]

Here you go mate. en.wikipedia.org/wiki/Stellar_classification. Nice vid! I did the same test on some broadband data and I also couldnt see a difference, even with pixel peeping. Think I read in the reference docs though that once you download and configure the gaia db, PCC uses that too, so maybe thats why?

[@viewintospace]

Thanks a lot for that! And no, PCC uses APASS - you can see that when you go in the PCC process and look under Catalog search - all you can chose are APASS processes. I guess that reason why we see no difference is that PCC works pretty well, And more correct that correct does not exist - so when PCC identifies the right star color, SPCC can also do not more......