Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

NGC4236 galaxy in Draco

  • Please log in to reply
6 replies to this topic

#1 Andreas_Roerig

Andreas_Roerig

    Vostok 1

  • -----
  • topic starter
  • Posts: 193
  • Joined: 25 Jun 2012
  • Loc: Westerwald / Germany

Posted 11 April 2021 - 05:46 AM

Dear CN members,
 
finally I finished processing of a new image.
It is NGC4236, a barred spiral galaxy in Draco.
 
ngc4236_ccdtn.jpg
 
I started this last year in April but was not that happy with the data. So this year I added some more frames.

Best regards
Andreas
  • lukasik, dswtan, lambermo and 17 others like this

#2 Mert

Mert

    Cosmos

  • *****
  • Posts: 8,029
  • Joined: 31 Aug 2005
  • Loc: Spain, Pamplona

Posted 11 April 2021 - 05:59 AM

Beautiful and sharp.

This object is rather dim in the outer arms and as such

can use all the time you want to expose!!

Well done!



#3 Max-OP

Max-OP

    Explorer 1

  • -----
  • Posts: 50
  • Joined: 05 Dec 2020
  • Loc: Orchard Park, NY

Posted 11 April 2021 - 07:43 AM

Oh man, I really like this image. Tremendous detail. Well done!



#4 elmiko

elmiko

    Fly Me to the Moon

  • *****
  • Posts: 5,957
  • Joined: 27 Jul 2009
  • Loc: Arizona

Posted 11 April 2021 - 10:00 AM

Turned out excellent Andreas!



#5 Andreas_Roerig

Andreas_Roerig

    Vostok 1

  • -----
  • topic starter
  • Posts: 193
  • Joined: 25 Jun 2012
  • Loc: Westerwald / Germany

Posted 12 April 2021 - 12:10 PM

Dear Mert, Max-OP and Mike,

 

thank you for your encouraging comments.

Also thanks to all the likers smile.gif.

 

Best regards

Andreas


  • elmiko likes this

#6 Dan_I

Dan_I

    Vostok 1

  • -----
  • Posts: 197
  • Joined: 22 Sep 2010
  • Loc: France

Posted 12 April 2021 - 02:17 PM

excellent image Andreas, sharp and colorfull very well done !

 

I have a similar telescope as yours with also the GPU corrector but I struggle to get nice stars in the corners. Which value of the backfocus did you settle with ? Thanks,

 

Dan



#7 Andreas_Roerig

Andreas_Roerig

    Vostok 1

  • -----
  • topic starter
  • Posts: 193
  • Joined: 25 Jun 2012
  • Loc: Westerwald / Germany

Posted 13 April 2021 - 03:27 PM

Thanks Dan,

 

the stars in the corners of my images are also not perfect. I always have at least one dirty corner frown.gif .

The distance of my chip to the corrector is around 54mm with my 8 inch f/4. On my 12 inch f/4 I add 0.5mm more.

The table below shows the recommended values for f/4 newtonians. If You  have filters in the optical path, You have to take  their thickness into account. 

 

 

ACHTUNG, der optimale Arbeitsabstand ist brennweitenabhängig und non-linear! Der Korrekor muss auch die Bildfeldkrümmung ebnen. Besonders bei kurzbrennweitigen Newtons zu beachten!
Die Tabelle gilt für f/4 Newtons, langsamere Newtons kommen mit 55mm Abstand gut aus.
F=600mm, Arbeitsabstand = 51,66mm
F=800mm, Arbeitsabstand = 53,66mm
F=1000mm, Arbeitsabstand = 55,0mm
F=1200mm, Arbeitsabstand = 54,66mm
ab 1500mm, Arbeitsabstand 54,60mm

 

(Source : Teleskop-Austria)

 

Best regards 

Andreas 


Edited by Andreas_Roerig, 13 April 2021 - 04:06 PM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics