21 replies to this topic

[reifheck]

Hi guys.

 

There seems to be a weird green tint to my Rosette Nebula .

 

 

Is it possibly due to my IDAS NBZ Nebula Booster UHS Filter ?

 

Thanks,

 

Reif

 

 

[ziggeman]

I've seen more pics with green in the Rosette. Including my own pics. The colors are real.

[MrDan]

Exactly how my STF's come out. Rather pretty.

Dan

[reifheck]

Exactly how my STF's come out. Rather pretty.

Dan

Thanks.

 

Another strange thing is in SharpCap, NINA, and ASIStudio Deep Sky Imaging, when I stretch the image the entire background turns green. Does that also make sense with the Filter?

 

I'm confused

 

Thank you ,

 

Reif

[Robert7980]

Yeah it’s the NBZ, you can adjust the colors later… 

Here’s an image with my NBZ… There are ways to remove the green or change it, but that’s what is causing it. 

[reifheck]

Yeah it’s the NBZ, you can adjust the colors later… 

Here’s an image with my NBZ… There are ways to remove the green or change it, but that’s what is causing it. 

Thank you Robert!

 

What do you use to remove the green tint? Or is it the real color?

 

Thanks again ,

 

Reif
 

Edited by reifheck, 19 March 2023 - 02:13 PM.

[Robert7980]

Thank you Robert!

 

What do you use to remove the green tint?

 

Thanks again ,

 

Reif
 

Where to begin… there are many ways, what editing software are you using?
 

[reifheck]

Where to begin… there are many ways, what editing software are you using?
 

I have Photoshop, Photoshop Elements, and Photoshop Lightroom.

 

What do you recommend and use?

 

Thanks,

 

Reif

[MrDan]

Another thought Reif and Robert,

On the 533mc pro the Bayer Matrix pattern is RGGB. One additional green pixel. In a linked stretched image there is a major green cast over the whole image. I remove it temporarily with an unlinked stretch in Pixinsight. Later a photometric color calibration will remove it.

Dan

[reifheck]

Another thought Reif and Robert,

On the 533mc pro the Bayer Matrix pattern is RGGB. One additional green pixel. In a linked stretched image there is a major green cast over the whole image. I remove it temporarily with an unlinked stretch in Pixinsight. Later a photometric color calibration will remove it.

Dan

Thanks. I'll give it a try.

 

Reif
 

[James Peirce]

Use SPCC and set it up with the proper settings. You’ll probably find it does a very respectable job of addressing the green bias that can be a bit stubborn on RGGB sensors. Also, OIII inherently lands somewhere in a green-blue color range, and presents with some of that green cast naturally. Some of it, though. I can tell in the stars around the Horsehead that you also have some of the green bias that usually takes a touch of fuss to calibrate out. Once you’ve calibrated it, link the channels in STF if you want to auto-stretch, as it still may want to give you a slightly green-biased stretch unlinked on account of the better signal vs noise in the green channel.

You see the stronger blues a lot because many people just kill the whole green color range with SCNR, which, overdone, actually gives a false color to OIII regions. (Which can also be a personal preference in editing.)

[Robert7980]

Another thought Reif and Robert,

On the 533mc pro the Bayer Matrix pattern is RGGB. One additional green pixel. In a linked stretched image there is a major green cast over the whole image. I remove it temporarily with an unlinked stretch in Pixinsight. Later a photometric color calibration will remove it.

Da

Could be the matrix, same process would apply in PS, unfortunately no color calibrators are in PS that I know of... I use PI for most of my Astro Editing, but PS comes in handy often.. It's just slower for many things.

 

This is fastest way I know of in PS to get the basic colors sorted out, there are hundreds if not thousands of tools in PhotoShop to adjust colors, and I'm by far NOT an expert at it... PI is much simpler far less powerful program, but it's geared toward Astro imaging... 

 

This was moving the Tint slider in Camera RAW Filter up 53... You can see your histogram change on the top, when all the colors are aligned then the colors are balanced... You can do the same thing in LIghtroom which is almost the same as the RAW filter... This was just a super quick edit to get the green back to what looks white to me... So the colors are roughly balanced, you can edit from there to taste... 

 

 

Edited by Robert7980, 19 March 2023 - 03:04 PM.

[Robert7980]

I left the green in the above for a reason, balancing the green out killed the color of the Flame so I decided to leave it... One could spend time masking it off and adjusting it separately to fix that but I didn't want to spend the time on it... So the color cast from the NBZ can be a pain depending on what your shooting with it..  I should have shot that target without the filter, so I plan on going back next year and reshooting it to fix it... I still like the image even though it looks a little weird...

 

-Edit-

On another note... If you think about it, the colors are actually not wrong, the filter picks up Ha (red) and OIII (green) only, that's it's job... So it's pretty much as it should be, it's not a "Problem" it's just different than without the filter...  It's a really good filter... So don't think less of it because it has this property.... 

Edited by Robert7980, 19 March 2023 - 03:18 PM.

[reifheck]

Use SPCC and set it up with the proper settings. You’ll probably find it does a very respectable job of addressing the green bias that can be a bit stubborn on RGGB sensors. Also, OIII inherently lands somewhere in a green-blue color range, and presents with some of that green cast naturally. Some of it, though. I can tell in the stars around the Horsehead that you also have some of the green bias that usually takes a touch of fuss to calibrate out. Once you’ve calibrated it, link the channels in STF if you want to auto-stretch, as it still may want to give you a slightly green-biased stretch unlinked on account of the better signal vs noise in the green channel.

You see the stronger blues a lot because many people just kill the whole green color range with SCNR, which, overdone, actually gives a false color to OIII regions. (Which can also be a personal preference in editing.)

What is SPCC ?

 

I'm new to processing astrophotography.

 

Thanks,

 

Reif
 

[reifheck]

I left the green in the above for a reason, balancing the green out killed the color of the Flame so I decided to leave it... One could spend time masking it off and adjusting it separately to fix that but I didn't want to spend the time on it... So the color cast from the NBZ can be a pain depending on what your shooting with it..  I should have shot that target without the filter, so I plan on going back next year and reshooting it to fix it... I still like the image even though it looks a little weird...

 

-Edit-

On another note... If you think about it, the colors are actually not wrong, the filter picks up Ha (red) and OIII (green) only, that's it's job... So it's pretty much as it should be, it's not a "Problem" it's just different than without the filter...  It's a really good filter... So don't think less of it because it has this property.... 

Thank you Robert!

 

I tried camera raw and see what you mean. I think I'll leave it and just try to get it to pop more.

 

Thanks again ,

 

Reif
 

[Robert7980]

What is SPCC ?

 

I'm new to processing astrophotography.

 

Thanks,

 

Reif
 

SPCC is a tool for calibrating colors in PixInsight.. It uses data from professional observatories to match star colors so the colors are as "real" as possible... It works ok, and it's a lot of work to use... If you are planning on processing a lot of astro-photos then PI is a really nice tool. It's fairly expensive an has a bit of a learning curve but it's well worth the investment in time and money to get the most out of the expensive gear we use. 

 

Most of the acronyms you'll see (SPCC, BXT, SCNR... ) are PI tools, the letters are easier to reference than the actual names because some get ridiculous like SPCC   

 

[James Peirce]

On another note... If you think about it, the colors are actually not wrong, the filter picks up Ha (red) and OIII (green) only, that's it's job... So it's pretty much as it should be, it's not a "Problem" it's just different than without the filter... It's a really good filter... So don't think less of it because it has this property....

Oh, I mixed up who was posting what.

On this note, it isn’t so much that you are picking up Hα (red) and OIII (between blue and green spectra and picked up on both channels), but rather than you are picking up Hα and OIII (with a little latitude around that spectra, contributed to by the forgiving bandpasses of the NBZ). So your representative color balancing in a lot of this will come out more naturally representative of those bandpasses than it may seem at first blush. If using Pix, SPCC tends to get a surprisingly good result. But as I think I saw you note, otherwise, color cameras may need an extra nudge to deal with a color cast introduced by the strong green bias. In your Horsehead, though, the red channel stands out quite strongly, which might also be nibbling away at the oranges in the flame nebula.

[James Peirce]

What is SPCC ?

I'm new to processing astrophotography.

As explained above, yep, a PixInsight tool, and abbreviated because some of those names are an exercise in absurdity. I mixed up a couple authors of replies above and thought you had access to PixInsight.

In Photoshop, a good first step is using levels adjustments to balance the channels (I think I saw that was explained above), and if you are stretching the image in Photoshop, to do that before stretching, and to keep those channels reasonably balanced during stretching (usually a few iterations of levels adjustments along the way) so a disparity between the channels isn’t introduced in the process.

[Bretw01]

Could be the matrix, same process would apply in PS, unfortunately no color calibrators are in PS that I know of... I use PI for most of my Astro Editing, but PS comes in handy often.. It's just slower for many things.

 

This is fastest way I know of in PS to get the basic colors sorted out, there are hundreds if not thousands of tools in PhotoShop to adjust colors, and I'm by far NOT an expert at it... PI is much simpler far less powerful program, but it's geared toward Astro imaging... 

 

This was moving the Tint slider in Camera RAW Filter up 53... You can see your histogram change on the top, when all the colors are aligned then the colors are balanced... You can do the same thing in LIghtroom which is almost the same as the RAW filter... This was just a super quick edit to get the green back to what looks white to me... So the colors are roughly balanced, you can edit from there to taste... 

 

 

 

 

Using the tint slider increases the magenta/red while decreasing the green. Instead try using the color mixer in camera raw and decrease the green saturation level, I like this better than SCNR in PI.

[reifheck]

SPCC is a tool for calibrating colors in PixInsight.. It uses data from professional observatories to match star colors so the colors are as "real" as possible... It works ok, and it's a lot of work to use... If you are planning on processing a lot of astro-photos then PI is a really nice tool. It's fairly expensive an has a bit of a learning curve but it's well worth the investment in time and money to get the most out of the expensive gear we use. 

 

Most of the acronyms you'll see (SPCC, BXT, SCNR... ) are PI tools, the letters are easier to reference than the actual names because some get ridiculous like SPCC   

 

Thanks.

 

I can't afford PI so I'll have to stick with PS.

 

Thanks again ,

 

Reif

[44maurer]

In Photoshop, try this free plug in.

 

http://www.deepskyco...ral algorithm. 

[reifheck]

In Photoshop, try this free plug in.

 

http://www.deepskyco...ral algorithm. 

Thank you Brian!

 

I'll give it a whirl

 

Reif