Adding RGB stars to a NB image

Discuss how you are able to get those fantastic images!!!
Post Reply
User avatar
umasscrew39 United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 233
Joined: Sat Apr 18, 2020 5:44 pm
3
Location: Florida
Status:
Offline

TSS Photo of the Day

Adding RGB stars to a NB image

#1

Post by umasscrew39 »


I've been trying several methods to add RGB stars to a narrowband image but I'm not pleased with any of them. More specifically, I want to add RGB stars to a starless narrowband image. I'd appreciate any approaches others have tried that they really like.

Thanks,
Bruce
Bruce

Astronomy? Impossible to understand and madness to investigate........Sophocles, c. 420 BCE

StarzantiSkies Observatory
https://www.astrobin.com/users/umasscrew39/
User avatar
KathyNS Canada
Co-Administrator
Co-Administrator
Articles: 0
Offline
Posts: 2584
Joined: Thu Apr 25, 2019 11:47 am
4
Location: Nova Scotia
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Adding RGB stars to a NB image

#2

Post by KathyNS »


I use PixelMath (in PI) to combine stars with starless images. If I was doing an LRGB image, the RGB stars have most likely been extracted from the nebula, so I would use addition to re-combine them.

But for overlaying RGB onto HOO or some other narrowband background, the stars really have no connection to the background. Using addition will cause the stars to take on the colours of the nebula, which I don't want. In that case, I will use a maximum function to combine them. That way, the stars get their full RGB value with no bleed-in of narrowband colours.
Image
DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
User avatar
umasscrew39 United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 233
Joined: Sat Apr 18, 2020 5:44 pm
3
Location: Florida
Status:
Offline

TSS Photo of the Day

Re: Adding RGB stars to a NB image

#3

Post by umasscrew39 »


ok- thanks for the suggestion, Kathy. I've been StarXTerminator to remove the stars but I think I was using the wrong PM formula to add the color stars to the NB image.
Bruce

Astronomy? Impossible to understand and madness to investigate........Sophocles, c. 420 BCE

StarzantiSkies Observatory
https://www.astrobin.com/users/umasscrew39/
User avatar
STEVE333 United States of America
Inter-Galactic Ambassador
Articles: 0
Offline
Posts: 3466
Joined: Sat May 11, 2019 5:01 pm
4
Location: Santa Cruz, Ca, USA
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Adding RGB stars to a NB image

#4

Post by STEVE333 »


Below is a link to a tutorial by Bill Blanchet who really understands how to use PixelMath, a very clever fella! Within the first 5 minutes of the tutorial he shows you how to transfer RGB stars into a starless SHO image using some icons that he provides. Good stuff!!


https://www.youtube.com/watch?v=nqnONWVwf-A


Hope it helps.

Steve
Steve King: Light Pollution (Bortle 5)
Telescope + Mount + Guiding: W.O. Star71-ii + iOptron CEM40 EC + Orion Magnificent Mini AutoGuider
Camera: ASI 1600MM Pro + EFW Filter Wheel + Chroma 3nm Siii, Ha, Oiii + ZWO LRGB Filters
Software: PHD2; APT; PixInsight ***** My AP website: www.steveking.pictures
Image
Image
User avatar
umasscrew39 United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 233
Joined: Sat Apr 18, 2020 5:44 pm
3
Location: Florida
Status:
Offline

TSS Photo of the Day

Re: Adding RGB stars to a NB image

#5

Post by umasscrew39 »


STEVE333 wrote: Mon Feb 06, 2023 9:45 pm Below is a link to a tutorial by Bill Blanchet who really understands how to use PixelMath, a very clever fella! Within the first 5 minutes of the tutorial he shows you how to transfer RGB stars into a starless SHO image using some icons that he provides. Good stuff!!

Excellent- thanks Steve!
Bruce

Astronomy? Impossible to understand and madness to investigate........Sophocles, c. 420 BCE

StarzantiSkies Observatory
https://www.astrobin.com/users/umasscrew39/
User avatar
Juno16 United States of America
Universal Ambassador
Articles: 0
Offline
Posts: 8195
Joined: Sun May 12, 2019 3:13 pm
4
Location: Mississippi Gulf Coast
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Adding RGB stars to a NB image

#6

Post by Juno16 »


Thanks for posting this Bruce.
Thanks for the link Steve @STEVE333.
Link saved in my Steve King file!
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
User avatar
STEVE333 United States of America
Inter-Galactic Ambassador
Articles: 0
Offline
Posts: 3466
Joined: Sat May 11, 2019 5:01 pm
4
Location: Santa Cruz, Ca, USA
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Adding RGB stars to a NB image

#7

Post by STEVE333 »


Juno16 wrote: Sat Feb 11, 2023 1:41 pm Thanks for posting this Bruce.
Thanks for the link Steve @STEVE333.
Link saved in my Steve King file!

Uhh-oh, I didn't know you were keeping incriminating evidence!!!
I'll need to be more careful in the future - chuckles

Steve
Steve King: Light Pollution (Bortle 5)
Telescope + Mount + Guiding: W.O. Star71-ii + iOptron CEM40 EC + Orion Magnificent Mini AutoGuider
Camera: ASI 1600MM Pro + EFW Filter Wheel + Chroma 3nm Siii, Ha, Oiii + ZWO LRGB Filters
Software: PHD2; APT; PixInsight ***** My AP website: www.steveking.pictures
Image
Image
User avatar
AstroBee United States of America
Moderator
Moderator
Articles: 0
Online
Posts: 2199
Joined: Thu Nov 14, 2019 11:03 pm
4
Location: Henderson, NV
Status:
Online

TSS Awards Badges

TSS Photo of the Day

Re: Adding RGB stars to a NB image

#8

Post by AstroBee »


If Bill ever starts charging for his PixelMath scripts, he'll be as rich as Russell Crowman before he knows it!
Greg M.~ "Ad Astra per Aspera"
Scopes: Celestron EdgeHD14", Explore Scientific ED152CF & ED127 APO's, StellarVue SV70T, Classic Orange-Tube C-8, Lunt 80mm Ha double-stack solar scope.
Mounts: Astro-Physics Mach One, iOptron CEM70EC Mount, iOptron ZEQ25 Mount.
Cameras: ZWO ASI2600mm Pro, ZWO 2600MC Pro, ZWO ASI1600mm
Filters: 36mm Chroma LRGB & 3nm Ha, OIII, SII, L-Pro, L-eXtreme
Eyepieces: 27mm TeleVue Panoptic, 4mm TeleVue Radian, Explore Scientific 82° 30mm, 6.7mm , Baader 13mm Hyperion, Explore Scientific 70° 10mm, 15mm, 20mm, Meade 8.8mm UWA
Software: N.I.N.A., SharpCapPro, PixInsight, PhotoShop CC, Phd2, Stellarium
https://www.nevadadesertskies.com
User avatar
Stuart United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 247
Joined: Sat Jun 01, 2019 11:12 pm
4
Location: East Bay, California
Status:
Offline

TSS Photo of the Day

Re: Adding RGB stars to a NB image

#9

Post by Stuart »


I haven't watched Bill's video, and his will be smarter than this, but here is one way.

1) Create a star mask. You can do it with Star Xterminator if you want, but best to either binarize it or to extract the lightness as the extracted stars on star exterminator have colors.
2) Place the star mask over your starless image
3) Open your RGB image with the stars you want to use to replace
4) Simple pixelmath of (RGB) onto your narrowband image to replace the pixels with your RGB pixels.
Personal equipment: TEC 140 F7 on Astro-Physics Mach 1 mount. Camera QSI 683ws7. Guide with Vario guiding scope
Shared equipment through Star Shadows Remote Observatory through PROMPT/ CTIO/Chile 16" RCOS 16803 chip
Shared equipment through San Diego Astronomy Society 14" RC with 16803 chip on a paramount
Software (for my stuff) PemPRO, SGP, PHD, Focus Boss, ASCOM, and Pixinsight on the other end.
Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

Return to “Image processing”