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Equipment Discussions >> Eyepieces

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Lance1234
member

Reged: 11/01/12

Loc: Santa Clarita, CA

What size barlow or Powermate do you use
#5635724 - 01/21/13 09:09 PM

Curious what size Powermates or barlows people use (1.25" or 2" or both); and if you use a 2", why? For purposes of this discussion I'm using the term barlow to refer to the whole class of Powermates, telecentric barlows, regular barlows, etc. Obviously a 2" barlow allows you to barlow 2" eyepieces, but why would you want to?

The benefit of a barlow, it seems to me, is that it enables you to get high magnification while using eyepieces with reasonable eye relief and good size eye lenses, rather than having to stuff your eye into a pinhole. Given that 2" eyepieces are only required when focal lengths get longer than the mid teens to twenty something mm, and then only for wide angle eyepieces, you can still get good eye relief & lens sizes in focal lengths that don't require a 2" eyepiece, i.e 16mm Nagler, 20mm XW, etc. So I would be interested in the benefit people see in using 2" barlows.

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GeneT
Ely Kid

Reged: 11/07/08

Loc: South Texas

Re: What size barlow or Powermate do you use new

[Re: Lance1234]
#5635795 - 01/21/13 09:57 PM

I have a 2" focusser and therefore use a 2" Powermate. If I used a 1.25 inch Powermate, I would have to us an adapter. I do have use an adapter for my 1.25 eyepieces, but I have outfitted all my 2" eyepieces with adapters. A 2" Powermate will also handle my 2" eyepieces.

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John Kuraoka
sage

Reged: 12/12/12

Loc: Sunny San Diego, CA

Re: What size barlow or Powermate do you use new

[Re: GeneT]
#5635822 - 01/21/13 10:12 PM

I have a 1.25" focuser and diagonal, so I use a 1.25" 2x Barlow.

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rathbaster
scholastic sledgehammer

Reged: 03/21/08

Loc: East Bridgewater, MA

Re: What size barlow or Powermate do you use new

[Re: John Kuraoka]
#5636032 - 01/22/13 12:31 AM

My primary scope can only use 1.25" eyepieces, so I use a 1.25" Powermate.

-Joe

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beatlejuice
scholastic sledgehammer

Reged: 04/05/11

Loc: Hamilton, ON,Canada

Re: What size barlow or Powermate do you use new

[Re: Lance1234]
#5636104 - 01/22/13 01:34 AM

I have 2 inch focusers but I use a 1.25 inch powermate because I don't have any 2 inch eyepieces that I want to power up. The TV 2.5 is great.

Eric

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ibase
Vendor Affilliate

Reged: 03/20/08

Loc: Manila, Philippines 121*E 14*N

Re: What size barlow or Powermate do you use new

[Re: beatlejuice]
#5636132 - 01/22/13 02:03 AM

Same here, 1.25" Powermate 2.5x.

TV 1.25" Powermate 2.5x, TV 2,3x

Best,

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johnnyha
Postmaster

Reged: 11/12/06

Loc: Sherman Oaks, CA

Re: What size barlow or Powermate do you use new

[Re: Lance1234]
#5636192 - 01/22/13 03:35 AM Attachment (13 downloads)

The 2" 2X Powermate with the body removed and a T-ring adapter installed, is imho the finest binoviewer barlow on the market. Gives superior images at high power and works in refractor, SCT or newt with no backfocus issues.

And unlike a regular 2X barlow, the telescentric Powermate stays at native 2X with the binoviewers (a regular 2X barlow is more like 3X-4X through binoviewers).

Now for regular eyepieces, I agree with the OP that it's silly to barlow 2" eyepieces. Love my 1.25" 2.5X Powermate!

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Damo636
sage

Reged: 08/16/11

Loc: Ireland

Re: What size barlow or Powermate do you use new

[Re: johnnyha]
#5636331 - 01/22/13 07:31 AM

Had a 2" Powermate but now use a 2" 1.6x Antares.

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MrFancypants
member

Reged: 07/05/12

Loc: Swift Current, SK

Re: What size barlow or Powermate do you use new

[Re: Damo636]
#5636337 - 01/22/13 07:35 AM

I bought a 2" for my 14mm ES 100 degree.

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David Knisely
Postmaster

Reged: 04/19/04

Loc: southeastern Nebraska

Re: What size barlow or Powermate do you use new

[Re: johnnyha]
#5636371 - 01/22/13 08:18 AM

Johnnyha wrote:

Quote:

Now for regular eyepieces, I agree with the OP that it's silly to barlow 2" eyepieces. Love my 1.25" 2.5X Powermate!

Well, it isn't really silly to Barlow a 2" eyepiece. One of my favorite combinations for globulars is my friend's 20mm Nagler and his 2x Powermate. In my Dob, it gives a nice wide field with just the right magnification (188x) to really start to "get into" the object without the field of view getting a little too restricted. There is also another reason to use a true Barlow: eye relief. If I use my 36mm Hyperion Aspheric with my friend's 2" barrel 1.5x Siebert Barlow, the eye relief gets extended enough that I can view pretty much the entire field of view with my glasses on. Clear skies to you.

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dpwoos
Pooh-Bah

Reged: 10/18/06

Re: What size barlow or Powermate do you use new

[Re: Lance1234]
#5636422 - 01/22/13 08:59 AM

Quote:

The benefit of a barlow, it seems to me, is that it enables you to get high magnification while using eyepieces with reasonable eye relief and good size eye lenses, rather than having to stuff your eye into a pinhole.

You cite one benefit of a barlow, but certainly not the only one. Many folks use a barlow to get more magnification from an eyepiece because they don't have another eyepiece that will do the same job as well. In fact, it may be that in their estimation there doesn't exist another eyepiece that will do the same job as well.

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Aquarist
sage

Reged: 08/27/12

Loc: Illinois

Re: What size barlow or Powermate do you use new

[Re: dpwoos]
#5636439 - 01/22/13 09:07 AM

2" Powermate

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csrlice12
Post Laureate

Reged: 05/22/12

Loc: Denver, CO

Re: What size barlow or Powermate do you use new

[Re: Aquarist]
#5636457 - 01/22/13 09:16 AM

Uh, none. I have a 1.25" 2X barlow--it sets in my case to soak up all the dew so the eyepieces don't get wet...Didn't intend for this to happen, bought the barlow fully intending to use it--and I did, initially, but after a time and obtaining additional f/l eyepieces, it now jus sets there. But, I'll keep it, you never know.....and everyone should have one barlow.

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Lance1234
member

Reged: 11/01/12

Loc: Santa Clarita, CA

Re: What size barlow or Powermate do you use new

[Re: David Knisely]
#5636583 - 01/22/13 10:24 AM

Quote:

One of my favorite combinations for globulars is my friend's 20mm Nagler and his 2x Powermate.

David,

Why just not use an 11mm Nagler or is it just the flexibility to double any EP?

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russell23
Post Laureate

Reged: 05/31/09

Loc: Upstate NY

Re: What size barlow or Powermate do you use new

[Re: Lance1234]
#5636853 - 01/22/13 12:55 PM

I have 1.25" and 2" barlows/powermates. I don't have a problem with barlowing my 2" 28mm ES68. In fact, if I wanted to spend the money, I could probably be perfectly happy with the 28mm ES68 and a couple of 2" Siebert barlows.

Dave

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Starman81
scholastic sledgehammer

Reged: 03/06/08

Loc: Metro Detroit, MI, USA

Re: What size barlow or Powermate do you use new

[Re: russell23]
#5637001 - 01/22/13 02:12 PM

In 1.25": TV 2x barlow, Orion Shorty 2x, TV Powermate 2.5x
In 2": GSO 2x ED barlow

Also, add me to the number of folks that don't mind barlowing 2" eyepieces. I barlow the 13 Ethos and ES100 9mm with great results and also the 22T4.

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David Knisely
Postmaster

Reged: 04/19/04

Loc: southeastern Nebraska

Re: What size barlow or Powermate do you use new

[Re: Lance1234]
#5637098 - 01/22/13 02:58 PM

Quote:

Quote:

One of my favorite combinations for globulars is my friend's 20mm Nagler and his 2x Powermate.

David,

Why just not use an 11mm Nagler or is it just the flexibility to double any EP?

It is the flexibility. I would have gone with the 11mm or 9mm Nagler except that I don't have either eyepiece. I have a 8.5-12mm Speers Waler that I can set to 10mm, but the view just isn't quite the same as the Nagler-Powermate combination. Indeed, using a Barlow instead of the Powermate will increase the eye relief as I mentioned, which in some cases for those of us who wear glasses can be a real boon to observing. For less complex eyepiece designs, going to the longer focal lengths provided by Barlows/Powermates can help their off-axis performance as well (mostly in somewhat reduced off-axis astigmatism). Clear skies to you.

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MRNUTTY
Carpal Tunnel

Reged: 11/22/11

Loc: Mendon, MA

Re: What size barlow or Powermate do you use new

[Re: David Knisely]
#5637345 - 01/22/13 05:03 PM

I have a 2x, 4x 2" Powermates for a slew of 2 inch TV's and ES100's. As long I can heft it, and it doesn't break anything, why not?

Edited by MRNUTTY (01/22/13 05:05 PM)

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Scanning4Comets
Markus

Reged: 12/26/04

Loc: Deep Space!

Re: What size barlow or Powermate do you use new

[Re: MRNUTTY]
#5637462 - 01/22/13 05:57 PM

Quote:

I have 1.25" and 2" barlows/powermates. I don't have a problem with barlowing my 2" 28mm ES68. In fact, if I wanted to spend the money, I could probably be perfectly happy with the 28mm ES68 and a couple of 2" Siebert barlows.

Dave

Dave, does the ES 28mm vignette in a barlow? I know my 28mm and 20mm Series 5000 did, but the 20mm ES 68 didn't. I'm now wondering if the Meade series 5000 68's and ES 68's are a bit different in lens design? Hmmmmm.

Cheers,

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russell23
Post Laureate

Reged: 05/31/09

Loc: Upstate NY

Re: What size barlow or Powermate do you use new

[Re: Scanning4Comets]
#5637521 - 01/22/13 06:41 PM

Quote:

Quote:

I have 1.25" and 2" barlows/powermates. I don't have a problem with barlowing my 2" 28mm ES68. In fact, if I wanted to spend the money, I could probably be perfectly happy with the 28mm ES68 and a couple of 2" Siebert barlows.

Dave

Dave, does the ES 28mm vignette in a barlow? I know my 28mm and 20mm Series 5000 did, but the 20mm ES 68 didn't. I'm now wondering if the Meade series 5000 68's and ES 68's are a bit different in lens design? Hmmmmm.

Cheers,

Mark,

That is an excellent question. I find that the 28mm ES68 with a 1.25" to 2" adapter doesn't seem to vignette in a regular barlow. At least the field stop is still clean and sharp. I've used it with 3x TV, 2.4x Dakin, and 1.5x Siebert barlows in this fashion. The adapter alters the magnification factor. The 28mm ES68 will vignette with the 1.25" to 2" adapter in a 2" powermate.

I have clear skies but it is frigid out. I wasn't going to go out, but since you asked this maybe I'll set up and take a quick look to give you some additional observations.

Dave

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