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

Bahtinov Mask for Binoculars

  • Please log in to reply
6 replies to this topic

#1 Stellify

Stellify

    Lift Off

  • -----
  • topic starter
  • Posts: 7
  • Joined: 07 Oct 2020
  • Loc: Surrey UK

Posted 16 October 2020 - 02:34 AM

Hi folks, 

Can anyone recommend a good Bahtinov mask for 80mm Binoculars? 

Thanks 


  • Foss likes this

#2 PEterW

PEterW

    Vanguard

  • *****
  • Posts: 2,341
  • Joined: 02 Jan 2006
  • Loc: SW London, UK

Posted 16 October 2020 - 02:43 AM

Never tried one, you could just buy a commercial unit the right size or 3D print them. Given stars are point sources I’m not sure why you’d want to use one?
Peter

#3 sg6

sg6

    Cosmos

  • *****
  • Posts: 9,257
  • Joined: 14 Feb 2010
  • Loc: Norfolk, UK.

Posted 16 October 2020 - 03:42 AM

You would need one for each side. Should be sites that generate the pattern for you, then you down load and cut out. Not sure what it would really accomplish as the main use is for imaging where you set the focus and then collect an hours worth of images without altering the focus. On binoculars I expect people tweek the focus all the time.

 

If I recall a Bahtinov Mask is dependant of both aperture and focal ratio so the aperture is easy (usually written on them) less sure about the focal ratio for them. But guess it needn't be totally accurate, good approximation should be adaquate.

 

Would be something that takes a little time as usually people have slightly different eyes, mine are 1/4 or 1/2 diopter different. With a mask I guess you set focus for the unadjustable half, then alter the dioptor for the adjustable.


  • Stellify likes this

#4 MB_PL

MB_PL

    Vostok 1

  • -----
  • Posts: 182
  • Joined: 04 Jun 2008

Posted 16 October 2020 - 03:52 AM

I've experimented with bahtinov masks for my 70mm and 120mm BTs. Too much hastle with very little gain, if any. They were only slightly useful at high powers when critical focus was very important. I'd say spend your time and money on other accessories.
  • Rich V. likes this

#5 cobrd

cobrd

    Lift Off

  • -----
  • Posts: 4
  • Joined: 31 Jan 2018

Posted 19 October 2020 - 04:53 PM

I have a pair of Helios 20x100 binoculars, and use a William Optics Bahtinov mask on them, one lens at a time.  Dimmer than a scope, but still usable.

I also use one on my 5" refractor with a binoviewer and find it excellent for setting the dioptre for each eyepiece in turn.



#6 Grimnir

Grimnir

    Apollo

  • *****
  • Posts: 1,145
  • Joined: 28 Apr 2010
  • Loc: London, England.

Posted 19 October 2020 - 05:08 PM

You would need one for each side.

 

No, only one is necessary.

 

I bought mine, laser cut from black plastic, for a few pounds on ebay. 

 

Graham



#7 KennyJ

KennyJ

    The British Flash

  • *****
  • Posts: 37,793
  • Joined: 27 Apr 2003
  • Loc: Lancashire UK

Posted 19 October 2020 - 05:16 PM

I think a Bahtinov must be just about the only variety of mask I haven't tried over the past 6 months or so!


  • Pinac likes this


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