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Decent planetary eyepieces?


ian_d

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Hi

I've been thinking about investing in a better short focal length eyepiece for planetary and other high magnification work. I currently use a 7mm Baader genuine ortho, but this suffers from a couple of issues: first, I can't bring it to focus with my 250PX f/4.7 Dob whilst using my Orion precision centering adapter (which is great, btw); and second, it's got a pretty small apparent field of view which makes for a lot of shoving the Dob around to keep targets in view.

Has anybody got any recommendations, or thoughts on ideal focal length? I'd want something that works well with my other 2 scopes as well (6" f/10 Celestron SCT, 4" Skywatcher f/5 achro refractor).

Interested in views!

thanks

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An idea of budget would help, and I guess you don't need much eye relief as you are fine with the 7mm BGO, Does your scope not have enough in-focus or not enough out-focus, because an extension tube would solve the latter.

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An 8mm Tele Vue plossl would be pretty decent unless you crave longer eye relief and / or a wide field of view - their focus point is a bit further outwards than orthoscopics.

The William Optics SPL 6mm might also be worth considering - they have much more eye relief and a wide field of view than plossls or orthos.

Eyepieces with wide fields of view do make tracking easier at high power with dobs but you need rather good ones to rival the contrast, sharpness and light scatter control that the Baader Genuine Ortho's have.

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Thanks guys. The extension tube idea makes a lot of sense (d'oh!) - pretty sure that will solve the focusing problem, and in fact a quick hunt through some old bits and bobs in the garage revealed that I've got an old cheap Barlow that I can unscrew the lens from - instant extension tube!

Were I to still want to upgrade I guess I would probably be looking for something like a Televue plossl or a Delos....not considered the WO one, will have a look.

Appreciate the help!

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I have the Nirvana 4mm and thats pretty good at planetary viewing. It sits between the 5mm and 3.5mm Pentax XW's but it's not outclassed by them by any means.

If you are going to think about the Delos you need to at least consider the Pentax XW range too Ian. Very little to pick between them from what I've read of the Delos.

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my BGOs focus more inward than other eyepieces I have so I fear it's a shortage of in focus you have. my recommendation based on what you say is a used Radian. not much more expensive than a BGO, better eye relief, wider field (60 degrees) and superb quality. you could consider a 5mm, 6mm, 8mm or 10mm.

the 'problem' with BGOs is that they are so cheap and so good despite their 'faults' (eye relief and AFOV) that they are hard to match in the same budget range.

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....the 'problem' with BGOs is that they are so cheap and so good despite their 'faults' (eye relief and AFOV) that they are hard to match in the same budget range.....

Hard to match even outside their budget range (on the upper side) :smiley:

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You are always welcome to have a go with my XW's Ian. I'll be at the meeting on the 12th and probably all the Stargazing live meets but I can't make the Glos. North observing sessions this month.

A 6mm Delos would be a good choice as well. An alternative would be the 10mm XW. This is a stonking eyepiece and barlows well to boot, so you could get two for the price of one with this option. With your Pan 24 and TV barlow would give you 24, 12, 10 and 5.

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Cheers Rik, would be good to have a go with your XWs - esp the 10mm as I reckon that would fill the most useful "hole" in my magnification ranges in all three scopes. See you on the 12th, and hopefully all the SGL events too!

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Now I have had a good few nights under my belt with is I have to say the 6mm Delos id one eyepiece that I would never get rid of, it is a cracker. I think in youe 250mm F 4.7 it would be right on the money, but sadly they are rather expensive.

Alan

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Ian

I would highly recommend either the 10 or 7mm Pentax XW. The views will all but match your BGO but the Pentax ep will be "much" more comfortable to use. So far I have resisted from springing for the 5mm, but its only a matter of time! I have owned the 10 & 6mm Delos and as John states above, there is really nothing to pick between them optically. I ended up going back to the XWs though as I found them just that bit easier to use.

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The Pentax XW's are extremely well thought of and to be sure are as close to perfection (especially in the shorter focal lengths) as you will ever find. If you do decide upon an XW I can't ever imagine that you would regret it.

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