What is the difference between the TeleVue big Barlow models

[SteveBz]

Hi Guys,

I was amazed recently by the difference between my ordinary 2" Revelation Barlow and the 1.25" TeleVue that a friend lent me, such that I don't think I continue without upgrading mine to a TeleVue 2".

What is the difference between the TeleVue big Barlow models, the one with green writing and flush adaptor and the one with silver writing and two adaptor screws.

The one with silver writing has two thumbscrews but is less aestheticly appealing.

What do you think?

Regards,

Steve.

 

[DRT]

I'm not aware of any optical difference but I think the newer version (the one with the white writing) has the top-hat style 2" to 1.25" adapter to accommodate the 1.25" EPs in the Ethos range.

[johninderby]

The one with the white writing is just the current version. 

BTW the big. Barlow isn’t recommended for use in 2” diagonals because of the length of the barrel. For 2”diagonals the Powermate is recommended.

[SteveBz]

8 minutes ago, johninderby said:

The one with the white writing is just the current version. 

BTW the big. Barlow isn’t recommended for use in 2” diagonals because of the length of the barrel. For 2”diagonals the Powermate is recommended.

I have a Newtonian.  Amazingly, and as advertised, the TeleVue Barlow improved my eyepiece!

Regards.

[DRT]

1 hour ago, johninderby said:

The one with the white writing is just the current version. 

BTW the big. Barlow isn’t recommended for use in 2” diagonals because of the length of the barrel. For 2”diagonals the Powermate is recommended.

I'm sure I read somewhere that the Big Barlow is designed to go between a refractor and the diagonal rather than the diagonal and an eyepiece.

[johninderby]

From the Televue website.

2" Big Barlow

Offered in a 2x magnification, the Big Barlow is ideal for Newtonian scope owners. It will be parfocal with both 2" and 1¼" eyepieces in this application. Features include 1¼" eyepiece adapter, threads for 48mm filters, captive lock screw and full multi-coatings.

Note: The Big Barlow is not recommended for use with 2" diagonals because it's length prevents it from being parfocal. With some telescopes, focus might not be reached, particularly when the interface lens is also used with it. A far better approach with no potential problems in any scope or with any eyepieces is to use the 2" 2x Powermate (PMT-2200). See the Powermates page for a discussion of Powermates vs. Barlows.

[bingevader]

12 hours ago, SteveBz said:

The one with silver writing has two thumbscrews but is less aesthetically appealing.

It's a bit naff!

Is that the latest one?

We'll have to start calling them 'white on blacks' then!

I wonder whose idea that was?

[johninderby]

The new version does look like an “economy” version of the old familiar one. Televues must have GREEN lettering on them. ?

The new version with lettering changed to green.