Skywatcher 2" ED Barlow?

[GazOC]

Skywatcher - Skywatcher ED Deluxe 2x two-inch Barlow Lens

Has anyone used one of these, specifically with a 13mm Ethos, or have any opinion at all on them generally?

Cheers.

[riklaunim]

Description doesn't say whats the diameter of the glass. GSO (Revelation) makes something similar: GSO 2" 2x Barlow and they say it can be used with wide angle eyepieces. This one is available at modernastronomy.

[Ben Ritchie]

Has anyone used one of these, specifically with a 13mm Ethos, or have any opinion at all on them generally?

I have one, and have used it with both the 8mm and 13mm Ethos. Nicely made piece of kit, not exactly TeleVue quality but SW have clearly stepped up their quality of late. Optically it seems fine, i've not tried to nitpick but equally haven't noticed any overt issues either, high-power on planets has been very good.

[GazOC]

Thanks guys. Thats very helpful.

[Demon Barber]

I use an Antares 1.6x barlow 2" fitting with my Ethos 13,the quality of the barlow is very goood only downside is it`s not a compresion fit,i was recommended this barlow by loads of Obsession users in the states and am well pleased with the views, i`m sure there was a reason for this barlow over 2x but cannot remember what i`m sure you would not be dissapointed if you go with this recommendation.

[Brinders]

I have the Skywatcher 2" ED barlow and compared to my TALs it is definitely a step up with no obvious false colour (which I think the TAL may be subject to) and no chromatic aberrartion.

I use it on both my Megrez 72 and the CPC925 in combination with my Moonfish 2" WA 32mm eyepiece and also with my Hyperion 8mm to good effect. I think it is great value for money.

Brinders

[GazOC]

You must have read my mind DB!!! I was looking at the Antares 1.6 last night as it would give me x193 using the 13mm Ethos in my Dob rather than x240 (which might be pushing it most nights in the UK) that a x2 Barlow would give and I could always use a little extension tube to increase the mag if the seeing as up to it.

[Ben Ritchie]

The Antares 1.6x is very good too, only reason I switched is that the 13E+1.6x barlow is virtually 8mm, and I have an 8E....

I've tried it side-by-side with the Astro-Physics BARCON (also 1.6x) and couldn't see a significant difference.

[womblemaster]

WOUld an ED barlow be superior to a celestron ultima barlow?

[Macavity]

The Antares (IIRC, sold to DAZ) was certainly nice - Even fitted Hyperions in 2" mode and was short enough for refractor diagonals. It would also fit in with the Ethos (ethos of?) scaling by 1.6x across a single e.p. series. Only other "feature" is that the Antares optics are fixed within, rather than screwed to the housing... And no filter thread (IIRC).

[KaStern_Former_Member]

Hi Folks,

I cannot recommend to use a negative-positive type eyepiece like the Ethos is

with a barlow lens.

The barlow alters the way the off-axis ray bundles take through the eyepiece.

Off-axis astigmatism control of the eyepiece will be changed, field curvature too.

Better use the Ethos alone.

Cheers, Karsten

[Kevin Ellis]

This is a copy of my posting last year on this barlow

"I have just purchased and returned a Sky Watcher 2" x 2 ED Barlow.

I took it to the Kelling Star Party to use with my 13mm Ethos in my 8" f4.5 newtonion. It was horrible as it would not come to focus correctly. A star test showed a large central obstruction on one side of focus and a very small central obstruction on the other. I got the same result in friends 20" f4.7 Dob. I was surrounded my many experienced astronomers who all confirmed my observations. By chance a vender at the Star Party introduced me to a customer who had purchased an identical Barlow. I found that his barlow gave the same horrible results as mine. I was also loaned a Meade 1.25" x 2 barlow and it worked just fine. There was very little difference between my barlowed 14mm Radian and my non barlowed 8mm Radian. It could be that the SW 2" x 2 ED Barlow does not like fast scopes which is a shame as I wanted to get more use out of my 13mm Ethos. It could be that both of the SW Barlows were just poor examples."

I now use a Televue X2 big barlow with my !3mm Ethos, which works fine.

[GazOC]

Just a quick update. I've tested my Skywatcher ED Barlow and 13mm Ethos out in a 14" f4.5 Dob and a 80mm f6.25 Equinox.

The Dob was just a quick look at the full Moon a week or so ago and showed no issues but obviously this wasn't really much of a test. The Equinox setup has had a more rigorous test over the last couple of nights and gives very good views right to the edge of field, I can't see the Dob+Barlow showing the same problems that Kevin described when I give that combination a sterner test than the Moon.

[Astro_Baby]

Sorry Gaz I must have misssed this post firts time round. I have the SKywatcher 2" ED Barlow and ini9tial results were very disappointing. I was running it in my 8" F5 Newt with a selection of Baader Hyperions and found the views were not good. A later test with the 5mm Hyperion showed quite good results (confirmed by two other observers at last years SSP) and I came to the conclsuion that early testing may have been just poor sky conditions producing bad results.

I have since used the 2" ED in the TAL with various lenses (including Hyperions with their strange inbuilt Barlow) and found the views to be good. I cant say how it compares to something like a Televue Barlow but certainly on Saturn a few weeks back it produced good results with a variety of lenses. I havent ever used it with the ES1400 simply because the weight/balance of such a huge EP on the end of a Barlow extension would IMO place too great a strain on things mechanically.

On balance it seems happier in the TAL than the newt but then what would you expect - everything performs better at F9 than F5 I guess.

By and large though I almost never use the 2" ED - not out of any deficiency just that the need seldom arises.

[GazOC]

Cheers AB,

I don't usually like using Barlows myself but with the price of the Ethos I have to be a bit more pragmatic and get the most out of the eyepiece!!

I've got an ES 100deg 20mm on order, it'll be interesting to see how that holds up. With that, the Barlow and the Ethos I'll have 20mm, 13mm, 10mm and 6.5mm which gives a great range of magnification in my Dob.

Gaz

[John]

Apologies for reviving this thread after a few months but I'm wondering if anyone has any further experience of barlowing Ethoi's ?.

I now have the 13mm and 8mm Ethoi's and an Antares 1.6x 2" barlow. The Antares barlow is excellent with both Ethoi's but obviously only delivers a new focal length when used with the 8mm, namely 5mm. In this thread Gaz mentions using an extension tube with a barlow to get higher amplification and I've read something on this elsewhere, eg: a 2" extension tube with the 1.6x barlow delivers around 1.9x amplification with a 13mm Ethos - has anyone else tried this and, if so, with what results (apart from a rather lot of stuff hanging out of the drawtube of course !).

Otherwise I'm thinking of either a) a Revelation 2" 2x ED Barlow or, pushing the boat out as far as a 2" 2x Powermate which I'm very confident of in performance terms but a little nervous of in weight terms.

[Astro_Baby]

Gaz - I ran a sort of test on the ES1400 against an Ethos at SSP. Astronut and Drummerp both had a look as well. Astronut kindly let me use his Ethos 13mm and we had a sort of shoot out. The results were hardly scientific but this was about the size of it....

Heres how they compared in a Celestron 9.25

M13 - Ethos showed core of the cluster perhaps marginally better but the ES1400 seemed to get the edge stars better defined. The ES1400 seemd a little darker and less bright to my eyes but Astronut felt he couldnt see much difference.

Double Cluster - Astronut felt he could detect the ES1400 vergfing on astigmatism at the edge of the field. I couldnt see it myself - I may have just not had good enough eyesight to spot it.

And heres how they performed in an F5 newt kindly loaned by DrummerP

M13 - hard to spot any substantial difference in the views. The ES1400 seemed perhaps very slighlt less well defined at the edge of the field. Astronut felt he couldnt see much difference

Double Cluster - View seemed identical - the ES1400 may have made stars at the edge o f the filed a little 'softer' but there wouldnt ahev been mcuh in it.

DrummerP felt the views in both were amazingly good in the Dob.

So there you have it - very little in it. The ES1400 is 1/2 a pound heavier in weight and its view to the eye is slightly different. Its hard to explain exactly but the way the 100' field hits your eyeball is subtly different in the two eyepieces.

My conclsuion was for what I paid for the ES1400 (about £300 I think) because the dollar rate was good and ES were hefting out a big dicount it made the EP a bargain. As close to an Ethos as anyone can likley get and probably no worse for anyone with a scope of F5 and upwards. The Ethos might win at F4.

BUT - and its a really big BUT ) at the prices Telescope House are asking for an ES1400 I'd buy an Ethos - last time I looked there was only a few quids difference and for a small amrgin I'd not have been willing to chance it and the Ethos might well have a better 2nd hand value long term.

At £300 the ES1400 was a bargain and if ES got a crunchy price together I am sure they could pull a few fans in.

I did consider springing for the 9 and the 20 on the latest ES deal BUT - and this is a personal thing - on the whole I dont f9nd the 100' FOV all that appealing. That may sound weird but I find its a strain on the eyeballs and about a 70-80' FOV suits me better.

I'll keep the ES1400 because it make a bit of a splash for some targets like the double clutsre but a bit of eyetime with it convinces me its not really what I like. The same is true of the Ethos - I found it a bit tiring on the eyeballs.

[Astro_Baby]

ps Gaz - I;d be very interested in how your 20m ES performs by the way. DO post up and let us know.

[John]

Intresting findings AB.

I don't know if you have ever tried a Pentax XW but, if not, you might enjoy the experience - they have all the sharpness and light transmission of an Ethos in a slightly smaller and more affordable, but no lesser quality (IMHO) package. FoV is 70 degrees and eye relief is 20mm across the range - very comfortable eyepieces to use.