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

Bresser 2x Barlow question:

beginner eyepieces
  • Please log in to reply
5 replies to this topic

#1 alexantos

alexantos

    Vostok 1

  • -----
  • topic starter
  • Posts: 125
  • Joined: 05 Jan 2019
  • Loc: Estoril, PT (White Zone)

Posted 25 April 2019 - 12:53 PM

The Bresser Barlow lens that I've purchased just arrived yesterday.

I got it on sale for 20€, so I think it was a bargain.

It looks and feels compact, with a full metal body, and it is full multi-coated.

The eyepiece hole is very tight, preventing it from shaking, keeping it always centered when I adjust the fixing knob.

 

I didn't have the chance to test it yet, and probably I only will do so next weekend.

 

My question is this:

If I detach the bottom part of the Barlow and attached it to an eyepiece, how much magnification should I get?

1,5x, the same 2x, or it doesn't work at all?

 

 

gallery_304439_10528_36291.jpg

 

gallery_304439_10528_126769.jpg

 

gallery_304439_10528_134600.jpg



#2 and75

and75

    Sputnik

  • -----
  • Posts: 34
  • Joined: 31 Aug 2010
  • Loc: Hungary

Posted 25 April 2019 - 01:16 PM

 

 

My question is this:

If I detach the bottom part of the Barlow and attached it to an eyepiece, how much magnification should I get?

1,5x, the same 2x, or it doesn't work at all?

 

you'll get 1,5x magnification and yes, it works



#3 CeleNoptic

CeleNoptic

    Apollo

  • *****
  • Posts: 1280
  • Joined: 20 Dec 2007
  • Loc: Mid-Atlantic, Bortle 7

Posted 26 April 2019 - 06:52 PM

My question is this:
If I detach the bottom part of the Barlow and attached it to an eyepiece, how much magnification should I get?
1,5x, the same 2x, or it doesn't work at all?


I believe it is a rebranded GSO 1.25" 2x Shorty" Achromatic Barlow I have. All telenegative Barlows work depending on eyepiece so the magnification factor varies. My GSO Barlow as is works at ~2.2x with most eyepieces except TV Delos (2.08x). The nosepiece screwed into eyepieces indeed works at 1.5x with most of them except TV Delos and Orion Ultrascopic (1.7x for both). Also, keep in mind that Barlows are optimized for work with certain extenders so the best quality view usually achieved in their native condition. If you're not very picky 1.5x also works, nothing wrong smile.gif


Edited by CeleNoptic, 26 April 2019 - 06:54 PM.

  • alexantos likes this

#4 MartinPond

MartinPond

    Fly Me to the Moon

  • *****
  • Posts: 5052
  • Joined: 16 Sep 2014

Posted 30 April 2019 - 09:37 AM

One great thing about 1.5x barlow-nose operation:

It makes your Plossl, 1,2-Konig, RKE, Ortho or other 2-5 element eyepiece

very happy with an F4, F5, or F6 telescope. And for those simpler types,

it also allows you to use an EP with more eye relief for the same net power.

So...that's two things.


Edited by MartinPond, 30 April 2019 - 09:39 AM.

  • nicoledoula and alexantos like this

#5 alexantos

alexantos

    Vostok 1

  • -----
  • topic starter
  • Posts: 125
  • Joined: 05 Jan 2019
  • Loc: Estoril, PT (White Zone)

Posted 03 May 2019 - 02:34 PM

I believe it is a rebranded GSO 1.25" 2x Shorty" Achromatic Barlow I have. All telenegative Barlows work depending on eyepiece so the magnification factor varies. My GSO Barlow as is works at ~2.2x with most eyepieces except TV Delos (2.08x). The nosepiece screwed into eyepieces indeed works at 1.5x with most of them except TV Delos and Orion Ultrascopic (1.7x for both). Also, keep in mind that Barlows are optimized for work with certain extenders so the best quality view usually achieved in their native condition. If you're not very picky 1.5x also works, nothing wrong smile.gif

 

I've tested it already and it works fine with the Plössl 25mm. The focus remains sharp, both at 1,5x and 2x, and as no aberrations whatsoever.

With the WA 60° is not so sharp, 1,5x works better than 2x, but anyway the eyepiece is not premium quality.

One other thing, I've opened the lens part and gave a little cleaning. It has 4 lenses, not 2 as the GSO.

 

One great thing about 1.5x barlow-nose operation:

It makes your Plossl, 1,2-Konig, RKE, Ortho or other 2-5 element eyepiece

very happy with an F4, F5, or F6 telescope. And for those simpler types,

it also allows you to use an EP with more eye relief for the same net power.

So...that's two things.

 

You're right.

I've noticed that as I said above. It's really sharp when using the Plössl.

Having not so much experience with Barlows, I would surely recommend this one, in a price/quality relation.



#6 Shorty Barlow

Shorty Barlow

    Apollo

  • -----
  • Posts: 1168
  • Joined: 15 Sep 2015
  • Loc: Lloegyr

Posted 25 June 2019 - 04:44 PM

I believe it is a rebranded GSO 1.25" 2x Shorty" Achromatic Barlow I have. All telenegative Barlows work depending on eyepiece so the magnification factor varies. My GSO Barlow as is works at ~2.2x with most eyepieces except TV Delos (2.08x). The nosepiece screwed into eyepieces indeed works at 1.5x with most of them except TV Delos and Orion Ultrascopic (1.7x for both). Also, keep in mind that Barlows are optimized for work with certain extenders so the best quality view usually achieved in their native condition. If you're not very picky 1.5x also works, nothing wrong smile.gif

Yes, it's almost certainly a GSO.




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





Also tagged with one or more of these keywords: beginner, eyepieces



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics