Star color

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gardenfish
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Star color

Post by gardenfish » Fri Jan 20, 2017 6:05 pm

Looking at the stars close up the colors are different on both sides. On my HSO when I line up the rgb channels in the center of the picture the stars on the left show blue sticking out at 7 oclock and green at 2 oclock. On the right side the blue is at 5 oclock and the green is sticking out at 11 oclock. I hope you understand what I mean.

Is this from field curvature? If I adjust the spacing of the ff/fr would this correct this?

Thanks Rick
ES127CF FCD100
CEM60EC on PierTech 2 in Roll-off observatory

Takahashi TOA150
CEM60 out side pier

SV70T

QSI6120WSG-8
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ST80 - AT60MM Guide scopes
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Doug
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Re: Star color

Post by Doug » Fri Jan 20, 2017 6:09 pm

Can you post an image showing what you mean?
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gardenfish
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Re: Star color

Post by gardenfish » Fri Jan 20, 2017 6:25 pm

I think you can see it here.

hso.jpg
hso.jpg (147.81 KiB) Viewed 9114 times
ES127CF FCD100
CEM60EC on PierTech 2 in Roll-off observatory

Takahashi TOA150
CEM60 out side pier

SV70T

QSI6120WSG-8
Astrodon LRGB
3nm Ha-OIII-SII

ST80 - AT60MM Guide scopes
G3 mono - ASI290MM Mini Guide camera's

Nikon D5200 Full Mod

gardenfish
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Location: Phoenix Az.

Re: Star color

Post by gardenfish » Fri Jan 20, 2017 6:27 pm

I you look lower right and then on the left the green and blue are on different sides of star center.
ES127CF FCD100
CEM60EC on PierTech 2 in Roll-off observatory

Takahashi TOA150
CEM60 out side pier

SV70T

QSI6120WSG-8
Astrodon LRGB
3nm Ha-OIII-SII

ST80 - AT60MM Guide scopes
G3 mono - ASI290MM Mini Guide camera's

Nikon D5200 Full Mod

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Doug
The good thing about science is that it’s true whether or not you believe in it. ― Neil deGrasse Tyson
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Re: Star color

Post by Doug » Fri Jan 20, 2017 7:23 pm

How are you aligning your stacked frames?

I'm wondering if alignment is the issue.
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DkN
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Re: Star color

Post by DkN » Fri Jan 20, 2017 9:10 pm

Are you shooting OSC or mono? If mono, then is this LRGB or NB? The error is radial. If mono, did you refocus between filter changes?
Jeff

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gardenfish
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Re: Star color

Post by gardenfish » Sat Jan 21, 2017 5:05 am

This is HSO with the Atik460. I never combined NB before so I aligned in rgb channels in ps as I know how to do that.. Probably not the correct way to combine nb but thought I would try it. When first put into the r-g-b channels it looks like a 3d picture without the glasses. when I align the channels to colors in the middle stars the edge stars are still misaligned and oppositely.

I did not focus between filters. When I set up I focused with the baht mask on Capella with the Ha filter. Then out of curiousity I switched to the OIII and the SII and without moving the focuser and still using the baht mask the focus was the same. These were the Orion 1.25 nb set that they claim parfocal. I have seen lots of revies of users and some say theirs are and some not. I am waiting on shipment of the 2" Astronomc NB's 6nm and am trying these until I get them.
ES127CF FCD100
CEM60EC on PierTech 2 in Roll-off observatory

Takahashi TOA150
CEM60 out side pier

SV70T

QSI6120WSG-8
Astrodon LRGB
3nm Ha-OIII-SII

ST80 - AT60MM Guide scopes
G3 mono - ASI290MM Mini Guide camera's

Nikon D5200 Full Mod

User avatar
Doug
The good thing about science is that it’s true whether or not you believe in it. ― Neil deGrasse Tyson
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Re: Star color

Post by Doug » Sat Jan 21, 2017 8:01 am

I think you should try an alignment software. PS is hard to align correctly and it takes a lot of time in PS.

What astro software do you have now? I think you should try stacking each layer first (HA, L, R, G, B) then align the final stacks in an astro program of your choice. The little differences you're seeing could be that little tweak you can't seem to find when you're manually aligning in PS.
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cgome004
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Re: Star color

Post by cgome004 » Sat Jan 21, 2017 1:40 pm

Try using he star alignment in pixinsight. You can pick one as the reference and then input the others to match the alignment. You can also then make an rgb image in pixinsight with the channel tool. It is probably more accurate this way rather than trying to manually match everything. Also do all of this with the data unstretched and in linear form

gardenfish
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Re: Star color

Post by gardenfish » Sat Jan 21, 2017 3:15 pm

But the center stars are aligned good it is the outsides that are off. So would this be the ff. curvature? If I align the left stars the center and right are off. If I align the right the center and left are off.

I will try the PI alignment tomorrow during the rain showers.

Thanks Rick
ES127CF FCD100
CEM60EC on PierTech 2 in Roll-off observatory

Takahashi TOA150
CEM60 out side pier

SV70T

QSI6120WSG-8
Astrodon LRGB
3nm Ha-OIII-SII

ST80 - AT60MM Guide scopes
G3 mono - ASI290MM Mini Guide camera's

Nikon D5200 Full Mod

gardenfish
Hypergalaxy
Posts: 1136
Joined: Fri Feb 05, 2016 9:18 am
Location: Phoenix Az.

Re: Star color

Post by gardenfish » Sun Jan 22, 2017 6:38 am

I am aligning in DSS. These are combining the 3 subs I am talking about
ES127CF FCD100
CEM60EC on PierTech 2 in Roll-off observatory

Takahashi TOA150
CEM60 out side pier

SV70T

QSI6120WSG-8
Astrodon LRGB
3nm Ha-OIII-SII

ST80 - AT60MM Guide scopes
G3 mono - ASI290MM Mini Guide camera's

Nikon D5200 Full Mod

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