Pacman Nebula - Forums

Topic starter

Dec 11, 2023 · Edited: Dec 11, 2023

If you were going to image the Pacman Nebula from a Bortle 2 site with an OSC camera (2600MC) and wanted to bring out as much color as possible, would you use no filter, a narrowband filter such as the L=Ultimate, or a filter like the L-Enhance?

Thanks
Jerry

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SemiPro

IOTD Staff

Dec 11, 2023 · Edited: Dec 11, 2023

There is a lot of dust around the Pacman Nebula that you really never see because everyone always does it in narrowband. If you are in Bortle 2 and have a reasonably fast telescope I say go for broke and try to bring out the dust with a broadband image. See the images below for an example.

https://www.astrobin.com/4hmq4a/?q=Pacman%20Nebula&camera=
https://www.astrobin.com/371292/?q=Pacman%20Nebula&camera=

I have to say, as a Submitter I see enough Pacmans that the usual SHO does not stand out anymore, especially because most people don't show the subtle transition from faint dust to nebula. Is just usually dark empty space and then bam! Nebula!

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estabrook

Dec 11, 2023

I agree with SemiPro. Take advantage of the dark skies and go filter-less!

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Jerry Gerber

Topic starter

Dec 12, 2023 · Edited: Dec 12, 2023

I agree. I think I'll go filterless.

Thanks..

kmcloughlin

Dec 12, 2023

Why not both? A couple hours with the L-ultimate and a bunch more with no filter, or just a UV/IR cut filter?

GalacticRAVE

Dec 12, 2023

Hi Jerry,

as argued by the others before I would definitly go filterless from the dark side, but possibly complement it with an l-extreme image taken from your standard light polluted place. In processing you probably want to make the images star less, properly mask the nebula regions to not spoil the faint dust regions of the deep rgb, and blend the nebula regions with screen. Depending on how well it works, extract an Ha and an Oiii image from l-extreme and continuum substract before screening. Looking forward to see the result some day, imaging from bortle2 is such an experience!

Matthias

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Jerry Gerber

Topic starter

Dec 12, 2023

Why not both? A couple hours with the L-ultimate and a bunch more with no filter, or just a UV/IR cut filter?

Hi Kevin,

I hope all is well with you. We're leaving tomorrow for a dark sky site, but not the one you and I went to, this one is more east, but still Bortle 2. It's going to be very cold, down to low 30s. Are we crazy or what???

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Alan Brunelle

Dec 13, 2023

I believe the ASI2600 has an IR/UV cut filter built into the optical window. If so, definitely go filterless. I use the QHY version of that camera, and it has no IR/UV cut. Therefore, I personally always use my L-Pro light pollution filter. One might argue that an LP filter is bad in a dark sky site, but the L-Pro lets through all the emission components that can be imaged from earth in astronomical target, yet lets enough of R, G and B through to yield a very good RGB image. In fact, every time I calibrate with SPCC with my OSC and L-Pro, the calibrated color shift is minimal, at most. So you would get those natural colors within emission components, yet get the dark dust and IFN components, and also true color reflection nebula components. If you look at my catalog, there is not one image there that does not use the L-Pro (except any NIR images). Without the IR/UV cut filter, going filterless with OSC will leave you at the mercy of UV and IR. Again, I believe that the ASI OSC does have that. So perfectly feasible and preferable to go filterless. And I agree with the other comments, the Pacman has been done to the verge of overkill with narrowband. If you go a bit wider field than most do, I think true RGB might be quite nice and a bit unique.

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Jerry Gerber

Topic starter

Dec 25, 2023 · Edited: Dec 26, 2023

I decided to image the Pacman nebula without filter. The seeing was a bit below average and the sky transparency was also a bit below average. But it was a Bortle 2 sky.

One thing I am learning about is how each nebula's blend of molecular hydrogen, oxygen and sulfur gases are different. Though I've chosen to use an OSC (asi2600MC) camera, I've discovered techniques in Pixinsight to bring out the various colors. But these techniques work well with some images and not so well with others, and I'm attributing that to the content ratio of each nebula. For example, here is the Pacman, NGC 281:

Here's NGC 7380:

And here is NGC 1491:

My question: In each case I used the same processing technique to bring out the SHO as best as I can using an OSC, but, as you can see, NGC 1491 isn't revealing these colors like the other images. I know it's not because those gases are not present because Timothy Martin just posted a beautiful image of the NGC 1491 that has a much wider color palette using a mono camera with filters. So what's making the difference? I don't think it's merely because of the use of a mono camera with filters, otherwise I wouldn't have been able to get the colors I did with the Wizard nebula using an OSC. There are probably techniques and processes in PI that I need to learn and apply, yes?

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SemiPro

IOTD Staff

Dec 26, 2023

I think the winning strategy is to embrace the broadband data and not go for an SHO look. You should be able to bring out really good colours assuming proper DBE (or perhaps GraxPert) and using SPCC. It does seem like you got some of the dust though!

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Jerry Gerber

Topic starter

Dec 26, 2023

I think the winning strategy is to embrace the broadband data and not go for an SHO look. You should be able to bring out really good colours assuming proper DBE (or perhaps GraxPert) and using SPCC. It does seem like you got some of the dust though!

Yeah, it seems like the "SHO" look is the "popular-boy-on-the-block" at present. Who knows, next year the most popular look may be black & white. No problem, the DSOs are very patient and will be around for millions or billions of years. We can experiment to our heart's content...

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