Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Best Barlow Options


Pig

Recommended Posts

Hi all

I have recently purchased a couple of Pentax XW eyepieces, the 14 & 20mm. I have been so impressed by them that I was thinking of buying more of the range. However, I came across the barlow shown in the link below and was wondering if this would be a slightly cheaper option as apposed to purchasing the 10mm & 7mm XW.

Any advice or other recommendations would be appreciated. The Scope it will be used in is an F5 triplet, I would like to keep the eyepiece/ barlow combined length & weight to a minimum.

http://www.harrisontelescopes.co.uk/acatalog/Carl_Zeiss_Abbe_Barlow_Lens_1.25_.html

Link to comment
Share on other sites

This Zeiss Barlow, of course looks very attractive but it's a telenegative Barlow if I'm not mistaken. It may not work well with long FL wide angle eyepieces with long eye relief. Make sure it provides enough clear aperture to avoid vignetting.  Don't know anything about this Barlow, but many telenegative Barlows make eye relief longer which may cause blackouts when it's too long.  It would be good if somebody who has first hand experience with a similar combination chime in. Otherwise, a telecentric extender like Bresser SA Barlow, ES Focal Extender or TV Powermate would be safer, IMO.

Link to comment
Share on other sites

Shaun,

The trouble I would find with Barlowing is they increase the eye-relief which is already 20mm, I wouldn't like this. It will take a good time to weed out these two from the S/H market so you have time to save for them.

Alan

Link to comment
Share on other sites

Alan,

I think that is the best course of action.....I will hold on until I find them, I am sure some will materialise at some point and if not I will buy them new :laugh:

Link to comment
Share on other sites

I've Powermated my Pentax XW's for fun and that works very well but at 5mm and 3.5mm "native" the resulting focal lengths are too much for any of my scopes.

I agree with you about the quality of the XW's. RikM collected a set of the 1.25" ones years back and those have been his mainstay ever since. Steve from FLO was prompting me to try them long ago when I was in the midst of "Nagler mania". When I did at last I realised what they were on about. Probably the best eyepieces I've used.

Link to comment
Share on other sites

John,

I caught a quick glimpse of Albireo last night with the 14mm, between the clouds, and the contrast of the orange and blue were just fantastic. They are great eyepieces.

Link to comment
Share on other sites

Probably the best eyepieces I've used.

That's very high praise indeed John

they dont come any better than that shaun :smiley:

Its my best Solar eyepiece with used with the Quark Mike...... The 9mm SLV was the Daddy with the Lunt 60mm and there wasn't much between the two.

Link to comment
Share on other sites

Yong,

I did think about the twist up eyecup and I agree that it does give a great deal of freedom, it is threaded very finely indeed thus adjustment can be extremely precise.

Thank you for the link I will read Bills post in a little while.

I have just read the full thread, I will take heed of his experiences and go for the eyepieces.... It was always my gut feeling and as my gut is getting larger the older I get I think I should follow it :grin: quite literally, as it in front of me

Link to comment
Share on other sites

I've Powermated my Pentax XW's for fun and that works very well but at 5mm and 3.5mm "native" the resulting focal lengths are too much for any of my scopes.

I agree with you about the quality of the XW's. RikM collected a set of the 1.25" ones years back and those have been his mainstay ever since. Steve from FLO was prompting me to try them long ago when I was in the midst of "Nagler mania". When I did at last I realised what they were on about. Probably the best eyepieces I've used.

That's more money I have to spend :grin: .

Alan

Link to comment
Share on other sites

Hi There,

For my two pence worth if you are going to barlow two brilliant ep's powermate them. I do not like using Barlows / Powermates. And as you have a triplet, treat your eyes to the prime lower F/L Pentax ep's.

Link to comment
Share on other sites

That's more money I have to spend :grin: .

Alan

I bought a 7mm XW intending to get the 10mm eventually but then I thought better of it because my Ethos's deliver very similar performance but more of it in FoV terms. So I'll stick to the 5mm and 3.5mm XW's where they really do a great job for me :smiley:

Sorry, that off the topic of barlows though. My latest Powermate 2x has just arrived though so thats on topic again, or very nearly :smiley:

Link to comment
Share on other sites

Well it must be my lucky day, I have managed to get a 7mm XW that should arrive this week and I should also be receiving the 20mm this week :smiley:

Link to comment
Share on other sites

Shaun,

The trouble I would find with Barlowing is they increase the eye-relief which is already 20mm, I wouldn't like this. It will take a good time to weed out these two from the S/H market so you have time to save for them.

Alan

My understanding is that if you get a telecentric focal extender they do not change eye relief, they just increase magnification with no other changes...  The powermate being one example of that... Seibert also makes such.... and the Explore Scientific ones too which are the least expensive but seem just as good.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.