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

"dark bucket" opposite focuser ?

  • Please log in to reply
5 replies to this topic

#1 macleod

macleod

    Viking 1

  • -----
  • topic starter
  • Posts: 938
  • Joined: 21 Sep 2014
  • Loc: Napier, New Zealand, 4110

Posted 16 April 2021 - 10:43 PM

I use my 13in f3 scope for deep sky and milky way cruising. Problem is I live on a hill in an urban area, with horrendous light pollution from 5x street lights + port and marshalling light towers below me, plus the " fishermans wharf" type village below me. No, I,m not going to move house its too nice a seaside area , except for Astro ! So I need maximum baffling, and I have a tube extension I fit to lengthen the OTA by more than the tube width. My OTA is a square tube with ventilation holes cut in the side, but I cover these with a shroud while observing

                                                                                                                                       post-233319-0-55468200-1618630459_thumb.

   I am wondering if I could improve my contrast further by adding an Ed Turco style light bucket opposite the focuser , and would it be worth the trouble ? I can easily cut a 45degree flat off the edge opposite the focuser, and mount a plastic box , suitably blackened and perhaps baffled inside - BUT what size box would I need ? My secondary is 88mm ( about 3.5in ) , my focuser a low profile Feather Touch, and as you can see points to the opposite corner of the square tube. So any ideas on dimensions , or whether it is worth doing would be gratefully received ! Thank you, Macleod                                                                                                                                    

Attached Thumbnails

  • DSC_0033-002 - Copy.JPG


#2 Barlowbill

Barlowbill

    Apollo

  • *****
  • Posts: 1,291
  • Joined: 05 Apr 2018
  • Loc: Tulsa, Oklahoma

Posted 16 April 2021 - 11:02 PM

It all looks pretty good to me.  Scope, location.  Are you Shure you want to mess with it?  



#3 MitchAlsup

MitchAlsup

    Fly Me to the Moon

  • -----
  • Posts: 5,401
  • Joined: 31 Aug 2009

Posted 16 April 2021 - 11:08 PM

Ed Turco light bucket might help a little,

 

But Black Velvet cloth {spray contact cemented to opposite side of focuser} might help nearly as much.

 

The way you can tell, is have your scope set up and ready to use, at night with dark adapted eyes but with no EP in focuser, place eye close to draw tube and look around and see where the stray light is coming from. Deal with the direct sources of stray light first, them move on to the indirect sources.


  • Pinbout likes this

#4 dave brock

dave brock

    Vanguard

  • -----
  • Posts: 2,348
  • Joined: 06 Jun 2008
  • Loc: Hamilton, New Zealand

Posted 16 April 2021 - 11:20 PM

What about a black polythene screen attached to the deck handrail?


  • kjkrum likes this

#5 dave brock

dave brock

    Vanguard

  • -----
  • Posts: 2,348
  • Joined: 06 Jun 2008
  • Loc: Hamilton, New Zealand

Posted 16 April 2021 - 11:24 PM

Isn't the tube corner opposite the focuser more or less a light dark bucket already? You're suggesting cutting it off

just to add it back in a slightly different form .


Edited by dave brock, 16 April 2021 - 11:32 PM.

  • dan_h and Pinbout like this

#6 macleod

macleod

    Viking 1

  • -----
  • topic starter
  • Posts: 938
  • Joined: 21 Sep 2014
  • Loc: Napier, New Zealand, 4110

Posted 16 April 2021 - 11:31 PM

Mitch, a good idea , hadn,t thought of that, it makes sense, will do first , thank you ! Dave, I have considered that, but along with a view comes wind - no not mine - and even a light breeze blows stuff around. Good thought tho ! By the way Dave, star test on the f2.98 mirror, a bit under corrected I think. Just made a mask to stop the 13in down to 12in , see what improvement it makes, and then widen it to 12.5in and see. Think a tde may be scattering a bit of light on bright stars . Don,t want to loose any more aperture than necessary of course !  Macleod




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