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

Star issues in Binoviewer

  • Please log in to reply
8 replies to this topic

#1 mikee

mikee

    Apollo

  • *****
  • topic starter
  • Posts: 1,260
  • Joined: 10 Jan 2005
  • Loc: Massachussets

Posted 29 February 2020 - 06:25 AM

Hi all -

 

I just picked up a cheap pair of Arcturus BV's a couple weeks ago.   The supplied eyepieces I had trouble with blackouts so they were really hard to test and get merging to work.   So I ordered a pair of AstroTech value plossls which are sharp @ 80% way to the edge of field when using in mono mode but I popped them into my BV's and the stars were all long streaks.   I had to pack up because of clouds before I could do much around adjusting but I've owned several pairs of BV's over the years from cheap clones to Binotron's and have never seen these artifacts before. Is this something that can be adjusted out or is it just completely out of alignment.   What's weird is in the 30mm supplied EP's while I had trouble using the EP's it didn't seem to be so wildly out of collimation (if that's what it is).   I haven't dropped or roughly handled anything so I'm not sure what's going on.

 

Any ideas?

 

Thanks!

Mike



#2 TOMDEY

TOMDEY

    Fly Me to the Moon

  • *****
  • Posts: 5,987
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 29 February 2020 - 08:24 AM

Hi, Mike. Are the new and old eyepieces same focal length? The BV co-alignment requirement tolerance is inversely proportional to eyepiece focal length aka shorter f means tighter tolerance on the BV. Long streak star images manifesting same both sides with one pair, but not the other --- could be something else also going on. I'd say re-check all 4 eyeps without the BV in there, to start to troubleshoot what's going on. Also... "cheap" would of course be suspect... possible dead horse.  Tom


Edited by TOMDEY, 29 February 2020 - 08:25 AM.


#3 junomike

junomike

    Hubble

  • *****
  • Moderators
  • Posts: 18,176
  • Joined: 07 Sep 2009
  • Loc: Ontario

Posted 29 February 2020 - 08:29 AM

Mike, Sounds strange to me (never encountered that issue.  I suggest trying both the 30mm and then the Plossl individually in both sides of the BV and see if that helps in determining the issue.



#4 mikee

mikee

    Apollo

  • *****
  • topic starter
  • Posts: 1,260
  • Joined: 10 Jan 2005
  • Loc: Massachussets

Posted 01 March 2020 - 09:37 AM

Hi, Mike. Are the new and old eyepieces same focal length? The BV co-alignment requirement tolerance is inversely proportional to eyepiece focal length aka shorter f means tighter tolerance on the BV. Long streak star images manifesting same both sides with one pair, but not the other --- could be something else also going on. I'd say re-check all 4 eyeps without the BV in there, to start to troubleshoot what's going on. Also... "cheap" would of course be suspect... possible dead horse.  Tom

Thanks Tom.. No the new EP’s are 20mm Plossl’s (astrotech value line) - both work as expected in mono vision.  The ones that come with the BV are 30mm but of unknown design.  They have very short barrels but that shouldn’t really impact anything.    They just tend to blackout for my eyes.  I’ve always had trouble with 30-32mm plossl’s blacking out for some reason but I have no problem with e.g. my Nagler 31mm..    Anyway I’m going to try and test it outside today and see if I can get it to merge and then setup again tonight if the clouds stay away. 


Edited by mikee, 01 March 2020 - 09:39 AM.


#5 mikee

mikee

    Apollo

  • *****
  • topic starter
  • Posts: 1,260
  • Joined: 10 Jan 2005
  • Loc: Massachussets

Posted 01 March 2020 - 12:13 PM

Just to report back - pretty sure they're completely out of collimation.  I just had them out with both sets of eyepieces  (20mm and 30mm) and the image of a distant pine tree top is smeared and can't be fully focused or merged.  I called Camera Concepts so hopefully they can take them back and get me another pair.

 

Thanks everyone for the help. 


Edited by mikee, 01 March 2020 - 12:15 PM.

  • Jon Isaacs likes this

#6 denis0007dl

denis0007dl

    Binoviewers Expert

  • *****
  • Vendors
  • Posts: 2,285
  • Joined: 17 Apr 2012
  • Loc: Umag, Croatia, Europe

Posted 01 March 2020 - 12:24 PM

Out of collimation: as I sayed numerous times, most China binoviewers comes that way even new from factory....

And worst is you can NOT collimate is by yourself....

...and thats where many binoviewers users give up from binoviewing usually...not all, but most...

#7 mikee

mikee

    Apollo

  • *****
  • topic starter
  • Posts: 1,260
  • Joined: 10 Jan 2005
  • Loc: Massachussets

Posted 01 March 2020 - 12:31 PM

That hasn't been my experience until now. I owned a StellarVue model and a WO optics model that worked great when I received them and put up great lunar/planetary views.   A little disappointed that these aren't in good collimation but I'm hopeful the dealer will let me return them for a pair that's in collimation.    

 

But I agree if this was my first attempt it may have turned me off from binoviewing.. It's frustrating but you get what you pay for and I was willing to take the risk of having to send it back if it was out of collimation.    Hopefully the dealer will support the product and let me return it. 



#8 junomike

junomike

    Hubble

  • *****
  • Moderators
  • Posts: 18,176
  • Joined: 07 Sep 2009
  • Loc: Ontario

Posted 01 March 2020 - 04:18 PM

Mike, An easy check (when you get new one's) is to do the "Reverse Moon" test first recommended by Glenn LeDrew.

Looking into the BV's in reverse with no OCS or EP's you should see a slight overlap.  If the Image is more than say half the Moon they are

excessively out of collimation.


  • AJK 547 likes this

#9 mikee

mikee

    Apollo

  • *****
  • topic starter
  • Posts: 1,260
  • Joined: 10 Jan 2005
  • Loc: Massachussets

Posted 01 March 2020 - 04:45 PM

Thanks Mike - I remember hearing that her on the forum and totally forgot!    I already packed up my current ones so I can't test but will do when the new ones arrive.

BTW Camera Concepts (they sell the Arcturus BV) was great to work with - no hassles at all and they'll be sending me a one in a few weeks when their new shipment arrives.  


  • Kunama 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