Barlow 1.25"v 2"

[slice of heaven]

Just ordered the12" gso from Andrews .What I need to know is;
Is there any benefit in a 2" barlow over a 1.25" barlow?
My old scope has a 1.25" focusser,(rack&pinion,smooth,no slop so I've no mind to change it) so if I go 1.25" I can use it in both .
But if the 2" has some benefit I'd consider that for just the gso. Both scopes are basically the same specs.The gso is more for the kids (yep kids like big buckets too) but being lighter I can see myself grabbing this one for the late night ,on my own viewing.
Also,opinions on a value for money barlow between $100-$200
would be appreciated.

Thanks,Geoff

[Starkler (Geoff)]

Originally posted by slice of heaven
Also,opinions on a value for money barlow between $100-$200
would be appreciated.

Orion Shorty PLUS 1.25"

Same optics as the Celestron Ultima. A great barlow, definately recommended. $150 at Bintel last I saw.
Not to be confused with orion Shorty, get the shorty PLUS.

The answer to the 2" vs 1.25' question is as simple as what eyepieces are you wanting to barlow? A quality 2 inch barlow is going to cost more.

[slice of heaven]

Thanks Starkler,
I have the shorty+ on my short list. 1 to Shorty

All our current ep's are 1.25" ,nothing expensive. So maybe what I should've also asked is what benefits do 2"ep's have over 1.25". I'm looking at upgrading the ep's verrrrrrrry slowly to some top quality but dont want to start off on the wrong foot.

So the new question is ; Is bigger better?????

Geoff

[Striker (Tony)]

My wife sayed something about bigger is better but I didn't realy understand and sent her back to the Kitchen where she belongs......lol

I know the 2" is obviously better in longer focal length eyepieces but with you having a Dob their probably isn't any use unless your thinking about getting 30-40mm eyepieces for extra wide viewing.....I think its personal.....I like 2" on the basis I see more for my money......eg......A Nagler 11mm 1 1/4 is about $100 cheaper then a Nagler 12mm 2" but is 3 times the size.....if I am spending big dollars on eyepieces I just prefer to see some size to the value....My personal opinion only....I like big.

[ving (David)]

if all of your EPs are 1.25 then you would be better off getting a 1.25 barlow. no sense in getting a 2" barlow if you dont have EPs to go in it.

2" EPs are good for the extra FOV they give you. I have got only one 2" EP (a 30mm GSO SV) and wouldnt dream of barlowing it as it would defeat the purpose of me getting it.

this said, if you plan on getting a collection of 2 inch EPs then go for it.

[vindictive666 (John)]

gday all

along the same lines can you get a adapter for a 2 inch barlow then will it take 1.25 inch ep's ?

I have the 2" powermate and it comes standard with the 1.25" adapter, I would think the barlows do likewise. Worth checking though.

[Striker (Tony)]

I think every 2"Barlow/powermate I have seen comes with a 1 1/4 adapter standard.....I could be wrong...their maybe a model or 2 that dont......

[ving (David)]

ah yes... didnt think of that!
get the 2" and put the adapter in it

D'oh!

[slice of heaven]

Thanks Striker (happpy birthday too) and Ving have taken both opinions on board,thanks.
In this situation I'm an absolute newbie as I've never seen a 2" ep let alone looked in one,same goes with ep's with a wide F.O.V. . So everyones opinion is very welcome.
I've no idea on what ep should or shouldn't be barlowed either (thanks Ving , another point I hadn't considerred) .

Geoff

[slice of heaven]

Thanks guys,
Wasn't sure if you could adapt 2" barlows to 1.25".Thats a good option......(Never seen a barlow either).
Powermates.....How much different / better are they to the barlow? .....and price for a 2x?

Geoff

[mch62 (Mark)]

Get the 2" as you will one day want a 2" EP and being able to use that 30mm or 40mm EP with a barlow is an advantage.
A 40mm wide field 2" eyepiece with a 2x barlow gives you a 20mm with similar characteristics of the 40mm. eg wide field , eye relief just higher magnifications.
I use my 2" EP's like this all the time even though I have numerous 11/4"EP that cover that range.
I just enjoy the easier viewing offered this way with the bigger glass.
If your on a budget the 2x GSO 2" barlow's are a bargain and come with a 11/4" adapter.
If your budget can afford it a Televue Powermate is better than a barlow , but they are expensive.
There are copies of a PM from Siebert Optics and Meade not wanting to miss out have jumped on the band wagon as well apparently .
The only reason not to get a 2" barlow would be you only have a 11/4" focuser or weight is a real problem in your scope.
Any others??

[vindictive666 (John)]

bintels prices on televue are


1.25 " (2x) $180
2 " big (2x) $335
1.25 " (3X) $180

https://www.bintelshop.com.au/


i followed the link from their page eyepieces and did an televue barlow search and thats what came up

not sure if prices are current though looks like the 2" comes with an adapter according to the picture best bet is to email or ring them

[ballaratdragons (Ken)]

Just had a look at Andrews website. He has finally updated it.

He has a 2" 2X barlow for $79. Don't know if it is any good though. It is on the 'Eyepieces' page.

Also just discovered he has a new section: Used and returned stuff. There is an 8" Dob with no base for $199. Be good for a big finder or mount on a GEM, or make a dob base.

[slice of heaven]

Thanks Vin,rang bintel & thats their price $330 for the barlow & $450 for the Powermate 2" 2x.
Has anyone done a comparison on these 2.

mhodson; Thanks for the feedback, easier viewing would be a big plus as my eyes aren't getting any younger and I'm looking for long term benefits.

[ausastronomer (John Bambury)]

I have got only one 2" EP (a 30mm GSO SV) and wouldnt dream of barlowing it as it would defeat the purpose of me getting it.

Hi David,

I also own the 2" 30mm GSO Superview and I can tell you that it barlows very nicely in my 2" 1.6X Antares barlow to convert it to a 2" 19mm eyepiece. The barlow actually cleans up the EOF very well by turning the F5 scope into an F8 light cone.

Clear skies
John B

[ausastronomer (John Bambury)]

Wasn't sure if you could adapt 2" barlows to 1.25".Thats a good option......(Never seen a barlow either).

Powermates.....How much different / better are they to the barlow? .....and price for a 2x?


Hi Geoff,

In the right telescope and in conjunction with the right eyepieces the powermates can show an improvement over a standard high quality barlow like the Orion Shorty Plus, Celestron Ultima and also the Televue barlows. The powermates are in a different class to the lower quality cheaper chinese/taiwanese barlows, which really I don't recommend if you have a decent scope and eyepieces. Another advantage of the powermate is that it preserves the eye-relief of the eyepiece used in it, whereas a standard barlow will extend the eye-relief by about 20%. If you are using short eye-relief eyepieces like orthos or plossls the extension of eye-relief by a standard barlow can be an advantage. The extension of eye relief on eyepieces with standard long eye-relief like Pentaxes or TV Radians can be a disadvantage and the powermate works best with those. Its really a case of matching the best barlow to your existing or proposed eye piece purchases. Remember however that with astronomical equipment that last 5% performance gain costs a disproportianate amount of money so $300 plus for the 1.25" 2.5X powermate is a lot of extra money for a performance gain of roughly 5% to 10% over the Orion Shorty Plus costing $150 or about $Aus 110 if you bring it in from Canada.

If you care to tell me what scopes and eyepieces you have and will be using the barlow in conjunction with I can advise you further.

Clear Skies
John Bambury

[trufflehunter (Wayne Robinson)]

Another thing to remember is some longer focal length 1.25" eyepieces, particularly if they are a wide-field design, will definitely 'vignette' in a 1.25" barlow.

I cannot use my 20mm Meade QX with my current barlow (a 'generic' one, but I suspect it's the same as the Orion Shorty) because of severe vignetting. It looks a bit like this:
<img src="http://www.users.bigpond.net.au/trufflehunter/vignetting.jpg">
The first circle is what it looks like thru the ep w/o the barlow, the second circle with the barlow!

Definitely looking for a decent 2" barlow...

[Starkler (Geoff)]

The Orion Shorty Plus has 27mm of clear aperture, which will handle most anything available in 1.25" format without vignetting.

[ausastronomer (John Bambury)]

Hi Truffle,

Geoff is 100% correct there, the Shorty PLUS with 27mm of clear aperture shouldnt present any vignetting issues for visual use. I have used it with my 20mm Pentax XW and the 24mm Panoptic without issue. The Orion Shorty is a cheap barlow and not in the class of the Shorty Plus, its internal field stop is only 22mm which is what causes it to vignette with the 20mm Meade UWA. Most cheap barlows will cause vignetting with long focal length wide field eyepieces. An expensive barlow which also has vignetting issues is the University Optics 2.8X Klee barlow. It only has a 19mm internal field stop and does vignette with "most" long focal length eyepieces (over 15mm FL) , however when used with the appropriate eyepieces, ie short focal length ones, the 2.8X Klee barlow does provide very good on axis performance.

Clear Skies
John Bambury