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

Planetary Imaging with C11 & Barlow

  • Please log in to reply
3 replies to this topic

#1 Astro-Andy

Astro-Andy

    Lift Off

  • -----
  • topic starter
  • Posts: 22
  • Joined: 06 Jun 2021

Posted 31 July 2021 - 04:07 AM

Hello all

 

I was wondering about the best & most practical (and least troublesome) way to set up my C11 for planetary imaging. The thing is, I have it perfectly set up for DSO imaging, and want to change this setup as little as possible.

 

What I would like to do is put my one of my Barlow lenses directly behind the filterwheel (in this case, a 1.25 Atik EFW2), as it connects beautifully to my ZWO ASI 120-s.

 

My questions are:

 

1) Is it feasible to put the Barlow lens (element) close to the focal plane, or at it (where the sensor would be), or would I need to set it for a wider dispersion?

 

2) What influence does a Barlow lens have on the backfocus of a system (Now, I'm set up perfectly with a backfocus distance of about 146mm, including the reducer, which I would take out, as I understand the backfocus will be the same without it)?

 

3) What adapter is needed to mate my 1.25" filterwheel to the Barlow (lens element) as there is no thread on the lens element.

 

My reasoning is this: Setting the Barlow-Cam. system behind the filterwheel (away from , and not towards the scope means I don't have to monkey around with the spacing before the filterwheel.

It would also make focusing easier, since I probably have to start with a bigger sensor camera to get centered and focused, and gradually work my way to the smaller sensor camera (or Barlow Cam. combination), recentering and focusing in small increments.

 

Regards

 

Andy



#2 Sarkikos

Sarkikos

    ISS

  • *****
  • Posts: 32,703
  • Joined: 18 Dec 2007
  • Loc: Right Coast of the Chesapeake Bay

Posted 31 July 2021 - 06:18 AM

Maybe this would be a better fit for the Imaging forum?

 

Mike



#3 jrschmidt2

jrschmidt2

    Vostok 1

  • *****
  • Posts: 122
  • Joined: 30 Jul 2020
  • Loc: Fitchburg, WI

Posted 31 July 2021 - 06:48 AM

Why not consider the Barlow IN the filter wheel.  Some of the (e.g. Celestron) Barlows have a "screw off" lens that are in a 1.25" form factor (just like the cheap 1.25" reducers), same form factors as 1.25" mounted filters.  I think this could go right into a 1.25" filter wheel.  Obviously the effective magnification will depend on the distance from the Barlow to the camera and will thus be different from the specs of the original Barlow (depending on your setup).  But this would give you something between 1.5-2x.



#4 Astro-Andy

Astro-Andy

    Lift Off

  • -----
  • topic starter
  • Posts: 22
  • Joined: 06 Jun 2021

Posted 01 August 2021 - 02:23 AM

Hi Mike

 

No idea, however, moderators feel free to move it.

 

@jrschmidt, only problem with that would be that I couldn't do RGB, since I work in monochrome.

 

Andy




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