Please suggest 14/15mm eyepiece for Binoviewers

[dweller25]

I am looking for a pair of 14 or 15mm eyepieces with around 60' field of view and good eye relief (>15mm) as I wear glasses.

I tried the TV 15mm plossls but they were not comfortable to use.

Looking at around £130 for the pair and a smallish barrel as I have a narrow IPD.

Anyone got any suggestions ???

[michael.h.f.wilkinson]

Not sure if the 15mm SLV would suit you. They get VERY good ratings and I find my 5mm very comfortable. The top of the EP is 50mm across, which may be too wide. If that is the case, try to hunt down some LV 15mm. These are optically similar, but are narrower. Apparently, the Dutch company Robtics still stock them (according to their website, which might be wrong)

http://www.robtics.nl/product_info.php?cPath=28_44_237&products_id=1112&pID=1112&language=en

[happy-kat]

Wasn't there a pair of maxvision 16mm in the classifieds for sale recently. Eye relief is close at 16mm.

[michael.h.f.wilkinson]

Wasn't there a pair of maxvision 16mm in the classifieds for sale recently. Eye relief is close at 16mm.

The 20mm MaxVisions had 15.5mm or so, and worked for me, but the 16mm has a slightly shorter eye relief, it is reported

[happy-kat]

Yes my mistake I thought it was longer, searching sho2s it to be tight. I don't wear glasses with mine so don't notice it.

[Mark in Macc]

You could consider a pair of 15 mm BST Starguiders. Very well regarded on this forum, with good eye-relief and not as wide at the top as the NLVs or SLVs. A pair will cost you less than £100.

[damnut]

Another vote for the BST's, do check the Celestron Excels also .

[dweller25]

Thanks for the link Michael

[dweller25]

Thanks Kat, Mark and Damian

[damnut]

Pleasure, hth or confuse :-) ..

[russ.will]

If the 10mm of ER of TV Plossls is too close (it's the limit of where I'm comfortable) the obvious suggestion would be a pair of 15mm Orthos which will have a couple of extra millimetres of ER.

Orthos typically have 75-80% of their focal length as eye relief, against the 60% of Plossls. It's a small difference, but when it comes to eye relief at these focal lengths, 2mm is enough. I'm comfortable at 10mm, but I'm now looking at Fujiyama 12.5mm Orthos because of this very reason.

Have a look at Lyra Optic, who are currently offering the best price in the UK on the Fujiyamas, which are the same as the the old BGOs, or the currently much more expensive Astro Hutechs, etc.

Russell

[Mark in Macc]

I don't think you can get orthos in the 15 mm format. They jump from 12.5 to 18 mm.

[Mark at Beaufort]

David (Dweller25) what scope are you using and its focal length?

I use 18mm Fujiyama Orthos in my binoviewers and last night had fantastic views of Jupiter in my Orion VX8 f4.5 Newt. To get the extra mag I use a 1.5x or 2.25x barlow. These Orthos, as Russell has stated, have 15.2mm eye relief and the quality is brilliant. I know the FOV is 42 degrees but I had no problem keeping Jupiter in the frame.

[dweller25]

Hello Mark,

@Mark_Beaufort : I am using a TSA102 (816mm FL) - I have a pair of Fujiyama 18's and as you say they are superb but only give me x138 (with a x2.6 GPC).

@Russel&@Mark_Macc : I wish I could get a pair of 15mm Orthos but your right they don't seem to exist.

[YKSE]

David, a more wild idea, maybe a pair of baader Q-T barlows can be an alternative? 1.3x to the 18mm give 13.8mm equivalent focal length.

[Dude_with_the_tube]

wrong wrong wrong 

15-16mm orthos/erfles do exist!

examples: Brandons 16mm  Carl Zeiss Jena 16mm ortho, Supermono 16mm, Meade Research grade 16,8mm ortho and 15.5mm erfle,and a few more. Issue will be the price bracket of £130. These Ep`s will be as min 85+ quid each.

If £130 is your maximum you are planning on your 16mm pair,i would recommend maxvision 16mm 68 degree ones as your bino pairs.I tested them personally and this pair works perfectly fine.Eye pieces are compact,views provided are sharp and contrast.They do have  12mm eye relief but it can be increased by a little with a simple cheat: dont wind up the rubber eye guards.Leave them down and that should give you a few mm more ER or go drastic approach and strip the rubber housing off and you will end up with even more compact eye pieces but in old "Smoothside" version.Takes 2 mins to do it and does not damage the eye piece and can be returned to original state at any time.New these are around £65 area,as such,will fit into your £130 budget.

David, a more wild idea, maybe a pair of baader Q-T barlows can be an alternative? 1.3x to the 18mm give 13.8mm equivalent focal length.

He cant do that as he is already using X2.6 GPC what is already a barlow at some part.And double barlowing in binos does not work.Option would be a ditch that 2.6 GPC and get like Baader VIP barlow what you can tune up to x3 or x4 or alternatively most expensive version of Zeiss barlow and tune that one up with rings.Expensive options tho.

There are not that many options really to have a 15/16mm pair with supreme 16+mm eye relief I am afraid and all that for £130 budget.

good luck and i am back to lurking.

[YKSE]

He cant do that as he is already using X2.6 GPC what is already a barlow at some part.And double barlowing in binos does not work.

Thanks, that's good to know, have you tested it yourself or can you point to the source where the test been done?

This one looks like WO spl, both specifications and shape,

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p3586_Astro-Professional-LE-Okular-14-5-mm-Brennweite---55--Feld---1-25-.html

[Dude_with_the_tube]

I have not tested it mate,but think logically.Binoviewers already introduce a slight loss of light transmission,due to number of prisms used to split the light cone.Now you add also a barlow to that,what is OK,but if you do add another barlow on top of one? how that is going to work?Also you still need to think of your ability to be able to reach focus.Barlow will push your focus out, and as stronger the barlow as more out focus you will need.And stacking glass on top of glass? i dont think this is a great idea.end result will possibly be a very dimm image due to double barlow usage.i dont actually think this will work at all.Not even worth testing it.Whats the point.Then the share size of that leaning tower of pizza in your focuser? this just asks for trouble

at the end,if budget is tight,there are always the cheap alternatives like BST Starguiders,WO clones (like the ones you linked in ).Dont expect wonders from these eyepieces or some breath taking views,but they will work and will provide great images.

[YKSE]

I have not tested it mate,but think logically.Binoviewers already introduce a slight loss of light transmission,due to number of prisms used to split the light cone.Now you add also a barlow to that,what is OK,but if you do add another barlow on top of one? how that is going to work?

Thanks, good to know that.

I think I will have to think again when recommending a pair eyepieces with fixed ER for binoviewers, they do have have build-in barlows, don't they?

[Dude_with_the_tube]

None of the binoviewers have inbuilt barlows.WO,Skywatcher,Maxbright and all the other clones use a simple barlow what screws into the nose piece of binoviewer,Televue uses its own design barlow or what they call amplifier or whatever the thing is called,Denkmier has its own design OCS  and powerswtich and lastly Baader mark V uses GPC.All these are non in build and can be removed.So if you can get your telescope to reach focus with binoviewer " as it is" or "native" without the need of using any of these devices,then in refractor 20mm eye piece will still be 20 mm and so on.Then you have the option of either using barlows or swapping other  focal length eye pieces to achieve different magnifications.Obvioulsy this doesnt work in maks/schmidts as even without any barlow binos will introduce some magnification.

All this does sound very complicated,but it isnt.Once you understand the principle,you are off.Good thing about binos,you can use a simple design eye pieces like erfles,plossls,orthos,kelners and get a really high quality image and this applies not only for planetary but also for DSO observations.Somehow the hype of binoviewers associates only with planetary observations,but this is not entirely correct.Good quality,large prism binoviewer is stunningly good for DSO too!

[YKSE]

I think I should have written more clearly:

"I think I will have to think again when recommending a pair eyepieces with fixed ER for binoviewers, they do have have build-in barlows, don't they?"

The word "They" meant the eyepieces with fixed ER, not binoviewers.
 

[dweller25]

@dude and YKSE - thanks for the eyepiece suggestions