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2 Weeks at Bortle 2 site in the desert: Witch Head & M33

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#1 ngatel

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Posted 16 October 2021 - 09:35 PM

gallery_20979_17102_324957.jpg

 

 

Aside from camping out and hiking a lot, my main goal was to capture the Witch Head Nebula.

 

gallery_20979_17102_1042882.jpg

 

 

 

 

Since it didn't get high enough until around 1:30 AM, I also imaged M33 while waiting for the Witch Head.

 

gallery_20979_17102_830992.jpg

 

 

I think I over-saturated the Triangulum and need to re-do it.

 

Both images used the same equipment and subs:

 

Sky-Watcher 100ED, ASI071MC Pro, Optolong UV-IR Filter

72 X 300sec @ 94 gain 30 offset
300 X 120sec @ 94 gain 30 offset

 

Now that I'm home, I'm planning on getting some Ha to add to the Witch Head, but I wait a month or two, as palm trees are in the way right now.

 

Oh, and while I was there, I added some RGB to the Heart Nebula I've been working on.

 

gallery_20979_17102_2816163.jpg

 

If anyone is interested, here a link to a trip report on my blog, which is really backpacking and camping oriented.


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#2 photobiker

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Posted 16 October 2021 - 09:57 PM

That is great.  Love the star colors in the Witch Head especially the orange ones shining through the nebula. You might have pushed M33 a little much but it is a pretty small target.

 

We do the camping thing too but it is mostly on the east coast.  We try to find darker areas to camp but they usually have a pretty good tree cover.  Once and awhile we get to your side of the Mississippi.  We're hoping to get out into mid-west in the March/April time frame next year and I'm bring as much gear as my weight limit will allow.  Just never know what you'll need.



#3 adosaj

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Posted 16 October 2021 - 10:06 PM

Very nice images. One thing I would say is that the star colors look off, by that I mean you have green stars and that is not very realistic. I see you are using APP which has an adjust star color tool. You draw squares around areas of your image that only have background stars (ie not from your main object) and it plots color-color plots for fitting. You should move the zero point such that in the B-R plot you have about 80% of the stars to the red and 20% to the blue (there is a slider for Blue to Red ratio and I move it just a few percent to the red, .05 or so) - I hope that makes sense. I find that doing this always gives me true star colors in the end.

 

There is a nice three part video tutorial on the APP site, https://www.astropix...sion-app-1-081/. It is for LRGB image processing, but the star color tool is used after combining the filters, so should apply to OSC images as well. 

 

Also, apologies and feel free to ignore my comments if you like it the way your images look now :)

 

Anil

 



#4 ngatel

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Posted 17 October 2021 - 01:59 AM

Thanks @ photobiker



#5 ngatel

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Posted 17 October 2021 - 02:03 AM

Very nice images. One thing I would say is that the star colors look off, by that I mean you have green stars and that is not very realistic. I see you are using APP which has an adjust star color tool. You draw squares around areas of your image that only have background stars (ie not from your main object) and it plots color-color plots for fitting. You should move the zero point such that in the B-R plot you have about 80% of the stars to the red and 20% to the blue (there is a slider for Blue to Red ratio and I move it just a few percent to the red, .05 or so) - I hope that makes sense. I find that doing this always gives me true star colors in the end.

 

There is a nice three part video tutorial on the APP site, https://www.astropix...sion-app-1-081/. It is for LRGB image processing, but the star color tool is used after combining the filters, so should apply to OSC images as well. 

 

Also, apologies and feel free to ignore my comments if you like it the way your images look now smile.gif

 

Anil

Anvil,

 

I usually sample the star colors in StarTools and sometimes use the star calibration routine in APP, which I know how to do.

 

But you are not the first person to tell me my stars are green.

 

I suspect my 71 year old eyes aren't what they used to be, plus my computer monitors probably aren't well calibrated, being 8 years old. I suspect it is time to buy a X-Rite or Spyder X calibration tool.


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#6 Mike in Rancho

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Posted 17 October 2021 - 01:56 PM

The first two do have excess green.  That's even after star sampling, huh?  Do you ever try the maxRGB toggle as a reality check on the sampling?

 

In that mode, you can dial back green, unless you know it's supposed to be there, and then cap off any remnants if you want to swerve it towards yellow.

 

But yeah the x-rite profiles have helped me also.



#7 ngatel

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Posted 17 October 2021 - 04:42 PM

Mike,

Thanks for the feedback. The problem is me adjusting the colors to what I “see.”

I usually do my processing on my 2013 MacBook Pro with a retina screen while sitting in my recliner. I have two 27” Apple Thunderbolt 2 monitors in my office, but I rarely use them (or my office) since I retired. I think I’ll buy a color calibrator and start using the Thunderbolt monitors.

#8 ngatel

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Posted 18 October 2021 - 12:32 AM

I re-did the two with green stars (I think). Do the look better?

 

gallery_20979_17102_2041599.jpg

 

 

gallery_20979_17102_416335.jpg


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#9 Cfeastside

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Posted 18 October 2021 - 09:31 AM

Great images and I enjoyed your blog!   Looks like theres a little bit if green or something still but much less of it.  



#10 adosaj

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Posted 18 October 2021 - 09:49 AM

They looked great before, but I would have to agree that the star colors are much better in the newer version. You can even see more spiral arm definition in M33. Before there was a lot of green hue that dominated much of the galaxy’s disk. I would love to get out to a really dark site soon!

 

Anil



#11 Mike in Rancho

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Posted 18 October 2021 - 08:01 PM

I like the fix!  waytogo.gif

 

Crazy how that one looks so much like it could be a regular earthbound water-vapor cloud.




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