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Premium eyepiece questions

mike-h

By mike-h
in Discussions - Eyepieces

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mike-h

mike-h

Posted
Posted

Does anyone have any opinions about whether Pentax XWs, Naglers or UWANs work well with 2x barlow lenses?

Also, what other options are there for eyepieces that would work very well in fast (f4.7) telescopes but also give a 60 degree or more FOV (plus decent eye relief!!).

Mike H

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A McEwan

A McEwan

Posted
Posted

Vixen LVW's are good in fast scopes, and are a bit more affordable than the others mentioned. Also, they all have 20mm eye relief and 65 degree apparent field of view. Haven't tried barlowing mine though.

Ant

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John

John

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I have barlowed Naglers and Uwans sucessfully although you do want to use a decent quality barlow lens to preserve their fine qualities. I found a Tele Vue Powermate 2.5x very good and also a Celestron Ultima 2x barlow although I did experience a little vignetting at the edge of the field of view with the Ultima.

I'd second Ant's recommendation of the Vixen LVW's - I owned a 22mm LVW and it was really excellent.

The Meade 5000's and the TS Planetary HR eyepieces might also satisfy your criteria of 60 degree FoV and good eye relief.

John

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Capricorn

Capricorn

Posted
Posted

I go with Gaz and Doc and never barlow. More glass usually results in more aberations.

Usually people want a barlow to give higher magnification then find that the scope cannot handle it.

The FoV of the eyepiece is one thing but the Apparent FoV when in use is another.

The Apparent FoV is (Eyepiece FoV)/(Magnification). So a 60 deg FoV will not result in anything even close to a 60 deg view.

If you get a barlow I suspect that the FoV of that is less then the eyepiece so the barlow FoV will be the limiting factor. A 60 deg FoV eyepiece plugged into a 50 deg FoV barlow will result in a 50 deg FoV.

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Doc

Doc

Posted
Posted
Thanks for the responses.

Will look into the Vixens.

Mick, is there an apparent difference if you barlow?

Would a 5mm perform much better than a barlowed 10mm?

Mike

A 5mm eyepiece will give you much better views, free from aberations, vignetting and just a darker image. Only plus point to using a barlow is eye relief in some eyepieces, especially ortho's.

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mike-h

mike-h

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I settled on the 10mm Pentax XW in the end. Recieved it Tuesday (from FLO).

Dying to use it!!!

If it doesnt barlow well then I'll buy a 4 mm planetary eyepiece.

Anyway, I should be fine with 10mm (x120), a 2.1mm exit pupil and a 70 degree FOV for many, many DSOs (I think).

Anyone recommend good planetary eyepieces??

Mike H

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MikeP

MikeP

Posted
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Mike,

I have 20mm, 10mm and 5mm XWs so I don't normally use a barlow. You won't be disappointed with the 10mm.

I started out with Meade 5000 super plossls set and had (still have) a 5.5mm. TBH, although it is a fine eyepiece, it was like looking through a pinhole. It was much more comfortable to use the 14mm and a (TAL) barlow. No such problems with the 5mm XW but as ever, not many opportunities to use it.

Mike

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A McEwan

A McEwan

Posted
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The FoV of the eyepiece is one thing but the Apparent FoV when in use is another.

The Apparent FoV is (Eyepiece FoV)/(Magnification). So a 60 deg FoV will not result in anything even close to a 60 deg view.

Sorry, I think this is slightly confused? Apparent Field Of View is the "mechanical" field of view of the eyepiece. The "True Field Of View" is the real field that shows when the eyepiece is being used, and is given by (Eyepiece Apparent Field Of View / Magnification).

The XW10 is superb! Congratulations!

Ant

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PeterW

PeterW

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Posted

Type 5... I must be the only one in the world with that one... or I just have a ham-fisted typing style. The 5T6 is a good one too...... Don't stand for <70degree fields of view!

Cheers

PEter

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John

John

Posted
Posted
Type 5... I must be the only one in the world with that one... or I just have a ham-fisted typing style. The 5T6 is a good one too...... Don't stand for <70degree fields of view!

Cheers

PEter

Hehe :) - if you come across a Type 3 be sure to let me know Peter - I don't think there ever were any !.

Regards,

John

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mike-h

mike-h

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I think I might give the 6mm TMB planetary a go. Decent eye relief, a useful FOV for my Dob and a good price. Not quite an orhto in performance but I only observe planets and the moon maybe 5-10% of the time. Can't really justify another pentax for this. Wish I could change the spelling on the title (premiun!!).

Thanks for the feedback everyone. Still can't wait to use the Pentax. Damn clouds.

Mike H

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