Barlowing a Hyperion Zoom

[lonebod]

Hi all,

I've got a Skywatcher Skyliner 200px.

I've recently purchased a Bladder Hyperion Zoom ep and matching Barlow. I've had a few issues using the Barlow because the draw when focussing max's out while still as 24mm. This means I can't the draw out further when moving to 20mm or lower.

I've tried a standard 2x Barlow and not got any issues.

I'm now wondering if I should have bought this instead. http://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-ed-deluxe-2x-two-inch-barlow-lens.html

Any ideas?

Is it possible to get a focuser with a longer draw? I'm thinking about replacing that standard one soon anyway.

G

[D4N]

Mine is very nearly par focal with or without the Barlow, I would guess you only need a few mm. Would using the 1.25" adaptor and connecting that way help, or are you already doing that?

Sent from my iPad using Tapatalk

[lonebod]

Tried it with the 2" and 1.25, same issue.

[Northern Soul man]

Hi Ya Lonebod, can you insert the zoom EP without the barlow and get focus, as D4n says - its nearly parfocal - so if you can get the zoom to focus, just by rotating the zoom gives you higher mags, but you shouldn't need to adjust the focuser to achieve focus - just check to see if you have the secondary mirror and focuser cradle all the way out (when "opening" up the scope if you store it with the secondary mirror housing fully collapsed) when setting up - sounds like the upper part of the scope isn't all the way out and your loosing a little travel because of this.

I might be wrong and tell me if I'm trying to tell you to suck eggs! - but with my setup, once I have achieved focus with the zoom - I just rotate to gain higher mags - and the whole movement from the 24mm to the 8mm is pretty much parfocal.

Paul.

[lonebod]

Hi. You of course correct re the parafocal aspect of the ep. Without the Barlow I am able to achieve focus no problem. I have double checked then scope set up before posting and everything is as it should be re the scope being full extended.

If add the Baader Barlow I can just get focus with the focuser fully out and the ep set to 28mm. The problem is that the ep isn't 100% parafocal and still needs just an extra 2 or 3 mm for get right down to the 8mm setting, but I've run out of focuser travel so can achieve this.

[YKSE]

Have you tried using the barlowed zoom directly in the 2" focuser? i.e. without using the 2" to 1.25" reducer?

The Zoom needs quite a lot inwards focuser, with the 2" to 1.25" reducer, it pushes out the zoom by some distance.

[lonebod]

Yes. Got the problem with both 2" and 1.25

[avtaram]

I have the Baader Zoom and Barlow.

When using the Zoom at the 8mm setting in my 12" Dob I found that there wasn't enough inward travel to achieve a really sharp image.

By using a low profile adapter instead of the one that comes with the diagonal I was able to achieve a sharp image.

My problem was with inward travel, yours you say is with outward travel, perhaps using an extension tube or a high profile adapter may help.

Avtar

[lonebod]

Was looking at extension tubes, but was also thinking about replacing the standard focuser with a dual speed moonlite. Can get it with up to 70mm travel.

http://www.firstlightoptics.com/moonlite-focusers/moonlite-cr-dual-rate-tri-knob-crayford-focuser-for-newtonians.html