Any drawback to using a barlow?

[Mak the Night]

1 hour ago, Dave In Vermont said:

An orthoscopic is my preffered planetary and other solar-system objects eyepieces. But if you need to wear glasses while observing, these may not be practical due to their short eye-relief. I also had an Orion-USA 'Shorty' Barlow - from which I removed the Barlow-lens from. This I use to screw into my eyepieces and/or zoom EP's for a boost in magnification by 1.5X or 1.6X - not sure which.

"If it t'aint broke - don't fix it!"

Dave

I have an Antares 15mm five element 'super' Plossl and a Baader 10mm Eudiascopic which I also believe is five element. They seem very much like orthoscopics to view through with their bright, very 'contrasty' images. I often use a pair of 18mm Baader BCO's in combination with a nosepiece Barlow with my binoviewer. The Barlow gives them quite a bit of eye relief, although too great an eye relief can often be just as bad as too little.

[Dave In Vermont]

The eyepiece designs for many EP's are inaccurately described as such entities as 'Super Plossl' and such. What some of these really are is Erfle's. Erfle EP's have been around a long time and do give a great view, with they're being both 5-elements and 6-elements.

I'll try to insert a diagram.

Have fun,

Dave

[Mak the Night]

1 hour ago, Dave In Vermont said:

The eyepiece designs for many EP's are inaccurately described as such entities as 'Super Plossl' and such. What some of these really are is Erfle's. Erfle EP's have been around a long time and do give a great view, with they're being both 5-elements and 6-elements.

I'll try to insert a diagram.

Have fun,

Dave

I'm not totally sure what the Antares is Dave. I bought mine recently as old stock for twenty quid more than I paid for a new TeleVue 15mm Plossl not so long ago. The Antares UPL series has now been discontinued. It's Japanese made and very well constructed. I believe it was marketed by Orion and Celestron at one time. It has a very similar, virtually identical, feel to looking through a genuine orthoscopic.

[Alan64]

13 hours ago, MarkVIIIMarc said:

Thanks again for much insight. 

I have two follow up questions.

Am I using google correctly and finding the PowerMates to be about $300?  or 3 to 6 times the cost of a Barlow?

My telescope is a Zumhell Z10.  They offer a 2" barlow for $50 something, or about 10 Jack n' Cokes lol.  Since Zumhell made my scope, do they make a reasonable barlow?

Your Zhumell reflector is a GSO product, as are these...

http://agenaastro.com/optical-accessories/barlows-extenders/1-25-barlows-extenders/shopby/gso.html

http://agenaastro.com/optical-accessories/barlows-extenders/2-barlows-extenders/shopby/gso.html

Traditionally, eyepieces of 15mm or shorter(6mm to 12mm) have been barlowed, and all of the 1.25" barrel-format.

[Dave In Vermont]

I'm intrigued. Though I wouldn't suggest disassembling it to find out!  

I have several Antares-branded orthoscopic EP's. And they're all excellent. And I have many other goodies from Antares - my neighbor to the North, Canada. One particular EP I L*O*V*E* is an older, original-series 10mm Speer-Waler ( Wide Angle Long Eye-Relief). The older series is mine - on the right.

Have too much fun!

Dave

[John]

The Antares Elite, Celestron Ultima, Orion Ultrascopic and Parks Gold Series are 5 or 7 element eyepieces but they are not related to the erfle design. If they were, their edge of field performance in scopes faster than around F/8 would be mediocre to poor, as erfles are. They are related to a Masuyama design however.

Antares have produced a wide range of eyepieces. Some are, frankly, awful in anything faster than F/8. Some are better. You need to do your research and (ideally) testing, carefully with Antares products. You can get something really good or, on the other hand, you can get something that is rather poor.

The above comments are based on the dozen or so Antares products that I've used plus other examples of the erfle design.

 

 

[Mak the Night]

20 minutes ago, Dave In Vermont said:

I'm intrigued. Though I wouldn't suggest disassembling it to find out!  

I have several Antares-branded orthoscopic EP's. And they're all excellent. And I have many other goodies from Antares - my neighbor to the North, Canada. One particular EP I L*O*V*E* is an older, original-series 10mm Speer-Waler ( Wide Angle Long Eye-Relief). The older series is mine - on the right.

Have too much fun!

Dave

Those look nice.

The Antares 15mm 5 element 'Plossl'.

[Mak the Night]

16 minutes ago, John said:

The Antares Elite, Celestron Ultima, Orion Ultrascopic and Parks Gold Series are 5 or 7 element eyepieces but they are not related to the erfle design. If they were, their edge of field performance in scopes faster than around F/8 would be mediocre to poor, as erfles are. They are related to a Masuyama design however.

Antares have produced a wide range of eyepieces. Some are, frankly, awful in anything faster than F/8. Some are better. You need to do your research and (ideally) testing, carefully with Antares products. You can get something really good or, on the other hand, you can get something that is rather poor.

The above comments are based on the dozen or so Antares products that I've used plus other examples of the erfle design.

 

 

I think I've read about the way they are related to a Masuyama design. There are some subtle differences from the Masuyama according to what I read.

[John]

13 minutes ago, Mak the Night said:

I think I've read about the way they are related to a Masuyama design. There are some subtle differences from the Masuyama according to what I read.

They tend to be referred to as Masuyama Clones. At one point I wondered if Masuyama actually were the manufacturer but I doubt that now.

Anyway, it's off topic from the original "any drawback to using a barlow" so I better not go on.

 

[Dave In Vermont]

Yes - an actual Erfle-design will turn into a mess with fast Newtonian - as I've encountered. In slower (older design) telescopes, they can be quite nice. They were originally made for use in military binoculars, after the second world war, astronomers with telescopes began to use them for their abilities to give wide-field views - at least that's the version I've read. I've always been fascinated by the designs of eyepieces - currently hunting a good Konig for my collection(s).

These are purported to be Erfles:

http://www.universityoptics.com/2inch.html#WS70

They have been sold with many brand-names attached. 'Titan' is one they have appeared as over in the UK & Europa. I have these in 2" with 32mm and 38mm FL. I picked these up for low-power - wide-views at 70° in my new F/12 Skywatcher Maksutov. As well as a "Super Plossl" in 50mm from Gary Russell of Russell Optics in Arizona. This will give a maximum lowest power of 36X in the F/12 Mak. I also have an order out for a 2" GSO 2X Barlow. Every end-user review speaks very highly of this piece of glass. And the price of $75US screams 'BARGAIN!!' at the top of the lungs.

Weather says 65F later today with thunder-storms. Spring!

Dave

[bomberbaz]

18 hours ago, MarkVIIIMarc said:

Thanks again for much insight. 

I have two follow up questions.

Am I using google correctly and finding the PowerMates to be about $300?  or 3 to 6 times the cost of a Barlow?

My telescope is a Zumhell Z10.  They offer a 2" barlow for $50 something, or about 10 Jack n' Cokes lol.  Since Zumhell made my scope, do they make a reasonable barlow?

Back on topic.

You are right the powermates are more expensive by some margin than most barlows but its a case of you know you are getting top quality. As I said I use a 2" fitting version as I use it in conjunction with my 2" eyepieces.

If however the budget is not in the powermate arena and you are sure you are only wanting it for 1.25" fitting eyepieces then a good quality 3 or 4 element 2x barlow will give you almost the same performance at much less cost.

Prior to having the Powermate I used a Orion ultrascopic http://www.telescopehouse.com/orion-ultrascopic-barlow-1-25.html as an example. Its a quality bit of kit and I was very happy with the performance it gave me, however once I went to the 2" fitting it wasn't suitable

Another option is the televue 2x barlow http://www.telescopehouse.com/televue-2x-barlow-1-25.html?gclid=CNPrmZzx7MsCFUSVGwodPGQJJA 

Celestron also do a high quality 2x version http://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-barlow.html

The version offered up by grotemobile also looks a good buy http://www.telescopehouse.com/barlows/bresser-barlows/bresser-sa-barlow-2x-1-25-inch.html

So any good barlow similar to above should suit your needs without busting your budget.

The cheaper 2 lens versions will still do the job but you are likely to find performance suffers at the business end so in reality it is false economy.

Have a look around and ask for opinion here before you hit the buy button, although at the end of the day the choice is yours o/c

 

[Mak the Night]

Interestingly, that Bresser Barlow looks very much like these Omegon Barlows:

http://www.omegon.eu/omegon-1-25-2x-premium-barlow-lens/p,32968

http://www.omegon.eu/barlow-lenses/omegon-1-25-3x-premium-barlow-lens/p,32969

They don't resemble any on the GSO homepage. I have one of these though (TS Optics): http://www.gs-telescope.com/content.asp?id=121

 

 

[bomberbaz]

3 minutes ago, Mak the Night said:

Interestingly, that Bresser Barlow looks very much like these Omegon Barlows:

http://www.omegon.eu/omegon-1-25-2x-premium-barlow-lens/p,32968

http://www.omegon.eu/barlow-lenses/omegon-1-25-3x-premium-barlow-lens/p,32969

They don't resemble any on the GSO homepage. I have one of these though (TS Optics): http://www.gs-telescope.com/content.asp?id=121

 

 

Probably clones of each other Mak. 

The GSO barlow is nice althoughI think the OP is looking at 2x versions although maybe a 2.5 would suit, hard to say without knowing what glass he intends barlowing

[Mak the Night]

53 minutes ago, bomberbaz said:

Probably clones of each other Mak. 

The GSO barlow is nice althoughI think the OP is looking at 2x versions although maybe a 2.5 would suit, hard to say without knowing what glass he intends barlowing

Those Bresser/Omegon clones certainly look impressive. They're not far off TeleVues in price! I'd love to know who makes them.

[bomberbaz]

28 minutes ago, Mak the Night said:

Those Bresser/Omegon clones certainly look impressive. They're not far off TeleVues in price! I'd love to know who makes them.

probably televue 

[Mak the Night]

28 minutes ago, bomberbaz said:

probably televue 

LOL!