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Ags

12mm planetary eyepiece...?

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I am looking for the best planetary eyepiece with a focal length of 12mm and a price of around EUR 100 new or used. 11-12.5mm are possible too.

I have thought of BST Starguiders at the cheaper end or these:

https://www.teleskop-express.de/shop/product_info.php/info/p8858_Kokusai-Kohki-Fujiyama-HD-OR-12-5mm---a-classical-Abbe-ortho.html

Or maybe this is all I need?

https://www.teleskop-express.de/shop/product_info.php/info/p148_TS-Optics-Super-Ploessl-Eyepiece-12-mm-1-25-.html

Or maybe one of these will come up second hand?

https://www.teleskop-express.de/shop/product_info.php/info/p1615_Pentax-XF-12mm---high-quality-allround-eyepiece-with-60--FoV---suitable-for-bino-v.html

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The Fujiyama Abbe Ortho (your 1st link) would be a really great choice for the role you have in mind. To get better in terms of sheer optical performance I think you would need to look at a TMB Supermonocentric or a Zeiss ZAO ortho, which are around 4x as costly, if you can ever find them.

Of course the Abbe Ortho shares the usual ortho attributes of tightish eye relief, a 40 degree AFoV and a smallish eye lens but for optical performance on the moon, planets and double stars,  I think they are very hard indeed to beat.

What scope will this be used with by the way - presumably something with a long focal length ?

 

 

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I would go for the first one on your list, which is an ortho. I have the Baader Genuine Ortho version of this and it is excellent.

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I think eye relief for a 12.5mm ortho would be around 9mm? Which would be OK I think. The use would be on a 102mm/127mm mak on a mount with tracking (AZ GTi). The idea is to have a 1mm exit pupil to minimise floaters. I'd prefer a bigger exit pupil but that would need a larger telescope!

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Your estimate of eye relief is about right I think. You will not really be pushing a 102 or 127 mak with a 12mm eyepiece though - I would be thinking of something that would deliver at least 150x - 180x, maybe a touch more on good, steady nights. So maybe an 8mm or 7mm eyepiece ?

 

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Personally I think you need more than x120 ish to observe planets to the full, not necessarily huge amounts more but x150 and x180 are useful. Do you suffer badly from floaters? Have you considered binoviewing? I do that all the time now and much prefer it.

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3 minutes ago, John said:

Your estimate of eye relief is about right I think. You will not really be pushing a 102 or 127 mak with a 12mm eyepiece though - I would be thinking of something that would deliver at least 150x - 180x, maybe a touch more on good, steady nights. So maybe an 8mm or 7mm eyepiece ?

 

Snap :)

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It's the binopaying I object to! I know 120x is not a lot, but I already have a 9.4mm eyepiece. If I could find an 8mm ortho for the top end, my life would be complete!

I do find Jupiter at opposition is quite observable at 120x, and the brighter image helps to show the colors of the planet even if the image is on the small side. However for me the problem at smaller exit pupils  is I only get a few seconds before floaters settle on my lens and completely block the view, so although the scope might be able to deliver more than 120x, my eyes can't!

Edited by Ags
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Yes,  that is a disadvantage. 

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How about Vixen SLV line?

I don't have personal experience with those, but from what I've read, performance is Ortho like, eye relief more than comfortable, and line happens to cover focal lengths that you might find useful (6, 9, 10, 12). Price is, I believe also within requirements (a bit more, but smack on 100euro without VAT :D )

 

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On the other hand, if interested in orthos only, TS has nice selection of Kokusai Kohki Fujiyamas, no 8mm, but they have 6, 7, 9 and 12.5 (among others) - again prices seem to be right (around 100e, this time VAT included :D )

 

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Yes, I have my eye on the Kokusai ortho line. Gotta squeeze every drop of performance out of my little maks!

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I think I'm right in thinking that a larger exit pupil reduces the impact of floaters on observing ?

If that is correct, your Skywatcher 150PDS should enable you to use a 5mm eyepiece (150x) and still maintain a 1mm exit pupil. Maybe the maks are not the best scopes for your eyes ?

It's getting late though so I might have that all wrong !

 

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1 minute ago, John said:

I think I'm right in thinking that a larger exit pupil reduces the impact of floaters on observing ?

If that is correct, your Skywatcher 150PDS should enable you to use a 5mm eyepiece (150x) and still maintain a 1mm exit pupil. Maybe the maks are not the best scopes for your eyes ?

It's getting late though so I might have that all wrong !

 

I think you are right - I calculate exit pupil like this: EP FL / Scope FR, so in case of F/5 scope - 5mm eyepiece will give 1mm exit pupil.

Or better remembered like this:

Eyepiece with focal length equal to F/ratio of scope will give 1mm exit pupil, and around half of that will be max theoretical useful magnification (based on resolving alone - perfect optics).

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That was my thinking (and was the reason I got the newt), but mounting the 150PDS was a problem. Besides, I didn't like the hairy stars Newts show. So I have gone back to smaller scopes. Guess I just like maks. But I do think of a C6 as the biggest exit pupil option for me...

Edited by Ags
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8 hours ago, Stu said:

Personally I think you need more than x120 ish to observe planets to the full, not necessarily huge amounts more but x150 and x180 are useful.

 

That’s my thoughts too.  With my 10” Dob, 150 -200x are good, but only if the seeing is steady enough. I keep a 9mm Ortho handy for 133x and find that better at times. A smaller and sharper view beats larger but fuzzier, good planetary views are much more dependent on steady seeing than eyepiece choice.

+1 for Orthos. I find the eye relief ok down to a 6mm, although I don’t wear glasses.

Ed.

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10 hours ago, Ags said:

That was my thinking (and was the reason I got the newt), but mounting the 150PDS was a problem. Besides, I didn't like the hairy stars Newts show. So I have gone back to smaller scopes. Guess I just like maks. But I do think of a C6 as the biggest exit pupil option for me...

I realise that they are quite expensive but I suppose that the Explore Scientific 152mm mak-newtonian might be worth considering in the longer term:

https://www.astroshop.eu/telescopes/explore-scientific-maksutov-newton-telescope-mn-152-740-ota/p,22534

With the mak-newtonian design you get a fast focal ratio (F/4.9) but the absence of most of the diffraction issues that a conventional newtonian produces so sharp "refractor type" stars and planets and good contrast. The MN design reduces coma to around 30% of the whats found in the newtonian design as well.

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I use these Ortho's in my 'scopes. First photo is my Circle-T 6mm & 12.5mm and the second photo shows a 6mm, (I think it is a 'Fullerscopes'), & 0.965"-1.25" adaptor.

PIC034.JPG.cfb717d6af3fd8005929be91025d20b4.JPGPIC036.JPG.256ee1ad02e01b954596c702e30a1d20.JPG

I did have a Baader 12.5mm that I puchased from @F15Rules but I sold that last year to someone who desperately wanted it. Within a few months @timwetherell was selling his 12.5mm and I purchased it.

Then there is my 13mm TeleVue's...

PIC044.JPG.54acb21c9b4e6e69cda54fdd37a1defe.JPG 

...from left to right... Plossl, Nagler Type 1 & Nagler type 6.

Edited by Philip R
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In the longer term, and with a heavy-duty mount under it, that would be a very yummy scope. 

I have tried Jupiter at 111x in my Newt and found that to be quite detailed despite the low magnification. It was hard to judge as the mount wasn't up to the task! Subjectively the image "felt" as big as the 150x equivalent in a 102mm mak, probably because of the better resolution and brightness.

I think I am just about sold on the ortho plan, but what about the Televue plossl option at 8mm and 11mm? Some claim they can complete with orthoscopics... They fit in my stated budget, but I'm aware that TV used to sell these for a lot less, so that annoys me a bit.

Then I would have (with 🙂 marking the oculars I actually currently own):

  • ES 24/68 🙂
  • Nirvana 16/82
  • Ortho/Plossl 11-12.5
  • Speer WALER 9.4/82 🙂
  • Ortho/Plossl 8
  • ES 6.7/82 🙂

And this would be for a Skymax 127 and an ST80 (which might eventually get replaced with a 70mm-ish apo).

The Speer WALER is currently my go-to eyepiece for planets, but it's not ideal as it suffers a bit from scatter and reflections. I used to have a Hyperion 17mm which operated at 9mm with fine tuning rings and that performed far better on planets.

Edited by Ags
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I don't think you can go wrong with orthos for planets, lunar and doubles😊..

The eye relief, although tightish, is better than plossls, and you can get them with smooth barrels too, unlike TV plossls ( unless they are old ones)..I hate undercut barrels!

Here are my 2 Baaders, 6mm and 12.5mm, and a new Fujiyama 12.5mm I have just bought...I've been looking for another BGO for some time for binoviewing, with no luck, so I might have to sell my BGO 12.5mm and buy a second Fuji 12.5mm if I can't find another BGO soon.

There is nothing to choose between BGOs and Fujiyama performance wise but the BGO is noticeably longer than the Fuji so they may not work well as an unmatched pair in my binoviewer..

Dave

IMG_20180910_191156670.jpg

IMG_20180910_190420869.jpg

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I have a 12 mm supermonocentric that's very nice on planets but with my scope's relatively short focal length (1250mm) it needs to be coupled with the 1.8 barlow to give something more useful magnification wise. I actually find the 12mm and 1.8 barlow preferable to use than the native 6mm mono just because the eye relief is better. UO orthos are also very nice EPs on planets and the moon and were (when they were available) vastly cheaper than the monocentrics!

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I like Orthos but started to find the eye-relief on the 12.5mm too tight so changed to a Pentax XF 12mm. Really like the comfort and they are just as sharp on the planets as the Orthos

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+1 for the Vixen SLV line, yes it's only 50deg but I find myself regularly ignoring my 10mm delos for the 10mm SLV.. I also updated to SLV from TV plossl's.. found the 20mm and 25mm SLV just went a bit deeper, with no regrets on the loss of green and black.

Small compact, incredibly sharp 20mm eye relief across the range.. very underrated and it shows on the second hand value.. last lot I saw 2nd hand went for just less than £50 quid, over half the new price..  What's not to love..

Mine wont be going anywhere soon that's for sure..

Ta

Fozzie

Edited by Fozzie
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