What binoviewer EPs and mag do you use?

[IB20]

What do people recommend for magnification and EP ranges for BV use (I seem to have fairly close IPD)?

[JeremyS]

I use Tak LE eyepieces in my Zeiss binoviewers + Baader 1.6 GPC.

[Neil_104]

I bino with my 10mm BCOs....but that's mainly cos these are the only eyepieces I have in a pair 😁  tbh though, I'm on the lookout for alternatives as I find they fog up really fast when it's dewy out due to the lack of eye relief. But in terms of sharpness they are superb, and ultra light and compact of course - ideal for bino use. They give 150x in my C6, which is pretty much the limit for planets most nights.

Edited December 18, 2022 by Neil_104

[Space Hopper]

Magnification ?

Low power, generally 40 - 65x  

Higher power i have a 2.6x Baader gpc which lives in its own prism diagonal, so i swap over the diagonal (easy and quick to do with the quick coupler) rather than fiddle about with the gpc's themselves.

I also have the 1.25 & 1.7x gpc's but don't use them so much, just tending to view san gpc for low power, and with the said 2.6x gpc for high power work (mainly lunar / planets)

Using the gpc for high power is important, as it corrects for prism induced spherochromatism. Always use a gpc rather than say, a pair of 3.5mm eyepieces.

With the 2.6x in place magnification is now 106x - 170x which is ideal for 90% + UK visual  high power observing.

 

I use 3 pairs of eyepieces :  Televue Panoptics in 24 and 19mm, and a pair of 15mm APM ultra flats, with a Baader Mk 5 viewer.  Scope is a 140 / 980mm apo refractor. I'm also testing a Zeiss mirror based viewer possibly the same as Jeremy's above.

I'm also considering fitting Dioptrx to my 24mm. 

In the past i've used a C8 SCT.  SCTs and binoviewers work well together (no focusing issues) as long as you keep the lightpath length as short as possible.

 

 

 

 

 

[IB20]

That’s a brilliant response, thank you. 

I guess my issue is, to achieve focus in the 76DC with the Revelation BVs I am having to add the bottom element of a Celestron Omni 2x barlow to the light path and I’m not quite sure what that is doing to the magnification - it seems higher than 2x with the 15mm plossls I have but I’m very inexperienced with BV set-ups. 

[Louis D]

I use the optics section of a Meade 140 2x Barlow on my Arcturus BV to reach focus and boost power by about 3x.  Most commonly I use 20mm Svbony UWAs and  vintage/adapted 15x (16.7mm) Bausch & Lomb microscope BV eyepieces.  I have also used 32mm Plossls and 23mm 62 degree Aspherics with varying success.  For me, I need long eye relief so I can wear eyeglasses due to 2.5 diopters of eye astigmatism which limits my choices.  I've tried larger wide angle eyepieces, but I couldn't fit my nose comfortably between the eyepieces.  The key thing is that the above eyepieces work well at f/12 and above.  Thus, I need the 2x Barlow to boost f/6 scopes to above f/12 (f/18 actually).

BV collimation is less critical with lower power eyepieces, so getting to higher powers with a Barlow, GPC, OCA, OCS, etc. and lower power eyepieces is preferable to using a pair of high power eyepieces without one.

[great_bear]

I use Meade S5000 “Plossls” of 20mm and 14mm in a Mak 180.  That gives me 162x and 231x (includes the 1.2x magnification caused by the binoviewer light path length in the Mak)

In the middle of the night - between 1am and 2am - there is occasionally a period when I can switch up to 286x for about 30mins by using the WO 2x binoviewer Barlow with the 20mm S5k’s (which causes a 2.12x magnification in the Mak)

Edited December 19, 2022 by great_bear

[MalcolmM]

Like @JeremyS, I use Tak LEs and find them very good. Also 28mm Tak Erfles which I find very comfortable to use. Unfortunately the above are no longer in production 🙁

My general approach is to keep the eyepieces light!

I have always found the magnification with Binoviewers to be more than one would expect given the respective focal lengths. Some say this is an effect of using two eyes. I think it also depends on where the GPC is placed. With my 100DC and Williams Optics Binoviewers, I have to place the 1.6 WO GPC onto the telescope side of the diagonal. I have always felt this seemed more like x2 and a bit rather than x1.6

I have recently got a pair of Maxbrights and I cannot recommend them highly enough. Much easier to use, a pleasure in fact and no merging issues. 

I know this is not really what your original post was about but the Maxbrights for me have transformed my binoviewing! And that's despite having really liked the WO ones in the first place.

I should caveat all the above by admitting I have not yet tried binoviewing with the 76DCU

Regardless, good luck!

Malcolm 

[mikeDnight]

I have used a cheap Revelation binoviewer since 2008 and love it. I use the binoviewer with a 2X barlow attached to its nose which amplifies about 4X. My eyepieces are mainly old 5 element Ultima's, Ultrascopic's, Parks Gold & Eudiascopic's (pseudo Masuyama's). They are very similar in design to the Tak LE's only a touch better in my view. Unfortunately  they are nolonger in production. I also use 16.8mm Kson Ortho's. I find that longer focal lengths in conjunction with a barlow on the binoviewer give a more comfortable view than the shorter fl's without a barlow. I like around 180X for Jupiter, 200X  to 250X+ for Saturn,  180X to 250X+ for Mars. I usually only observe with relatively small aperture scopes, so the resolution is obviously limited; however using both eyes massively improves the ease with which subtle detail is seen. The only drawback for me is that binoviewer tend to be critically adjusted to a single observer, which can take some time to get right. This means that they are unlikely to suit another observers vision and would need adjusting. Then they can become a pain.

Below are my pseudo Masuyama's and  binoviewer in two of my scopes. The binoviewer has for me been the most impressive accessory I've ever bought.

 

[IB20]

Some superb responses, thanks all. I’m thinking I might try the 18 or 32mm BCOs, does anyone have any experience with these? I have the 10mm & 6mm and I really rate both so assume they are just as good?

[Highburymark]

I have pairs from 4mm to 40mm - mostly Plossls, Delites and microscope eyepieces, but also Panoptic 24s and Morpheus 12.5s for wider viewing.    
Solar hydrogen alpha and white light, and lunar, are almost 100% binoviewed these days. I’m so accustomed to using two eyes for these purposes that I now find single eyepieces almost physically uncomfortable. I use binoviewers about half the time for planets, but still use specialist single planetary eyepieces otherwise.
Magnifications are:     
Between 120x and 250x - lunar and planets.    
Between 40x and 150x - solar Ha.    
Between 140x and 225x - solar white light, depending on seeing.     
I haven’t used any BCOs, though hear they are excellent for binoviewing. Light, sharp and affordable. The 32mm Baader Plossls seem to work well for solar as the eye lens is nicely recessed to block out unwanted light.  
Generally, binoviewing is a great leveller - even cheap eyepieces and binoviewers tend to work well for most purposes - as Mike says above. Pricier gear gives you either wider views or a little better performance at high powers.   The most important thing is to make sure they are perfectly collimated to make merging easier and ensure longer observations are comfortable without eye strain.

[Franklin]

1 hour ago, IB20 said:

I’m thinking I might try the 18 or 32mm BCOs, does anyone have any experience with these?

The BCO 18mm make a great bino pair, excellent, can't fault them. The BCP 32mm did show some slight vignetting both in WO and Maxbright binos, possibly not in the newer Maxbright II as they have a slightly larger clear aperture? BCO 10mm work very well also, but the BCO 6mm was a touch too much for me.

[Louis D]

As far as the BCOs, it might come down to if you need astigmatism correction for your eyesight at lower powers and thus larger exit pupils.  The 18mm would be too tight for eyeglasses, but the 32mm might work, depending on eye lens recession.  BTW, I couldn't find a 32mm BCO, only a 32mm Baader Classic Plossl.  If that's the case, I doubt if you could extrapolate anything from the BCOs to it.  I'd probably look for a pair of vintage 30mm Ultrascopics/Eudiascopics instead.  They're known to be of exceptional visual quality.

[IB20]

I have a 12.5mm & 7.5mm ultrascopic, they are exceptional EPs. I am keeping my eye out for the 30mms but they are pretty rare on the 2nd hand market. 

[Highburymark]

1 hour ago, Louis D said:

As far as the BCOs, it might come down to if you need astigmatism correction for your eyesight at lower powers and thus larger exit pupils.  The 18mm would be too tight for eyeglasses, but the 32mm might work, depending on eye lens recession.  BTW, I couldn't find a 32mm BCO, only a 32mm Baader Classic Plossl.  If that's the case, I doubt if you could extrapolate anything from the BCOs to it.  I'd probably look for a pair of vintage 30mm Ultrascopics/Eudiascopics instead.  They're known to be of exceptional visual quality.

Yes - Baader only makes a plossl at 32mm but it’s packaged with the classic orthos. And you’re right about the 30mm pseudo Masuyamas - they are glorious in a binoviewer

[Paz]

The ultimate magnification you can go to is still limited the same way by the seeing, but if you have significant  floaters that ate a limiting factor in cyclops mode you may find you can go to higher magnifications and smaller exit pupils better with binoviewers.

The magnification factor of a Barlow or glass path corrector depends on how far in front of the eyepiece it is. In cyclops mode a Barlow goes immediately in front of the eyepiece so they are close and the magnification is usually what it says on the tin. If you put a binoviewer in between a Barlow and 2 eyepieces the distance is greater between them and so the magnification factor is higher.

 For example if I put a 2.6x glass path corrector right in the nose of my binoviewer (where it is expected to go) it does 2.6x but if I add spacers to the it or say if I put it in front of the diagonal so it's even further ahead it will be making 3.4x or even more.

[Stardust1]

I use magnification around 150x for the planets and the Moon.

My most used pairs are Morpheus 17.5 and 12.5 by far.

Edited December 27, 2022 by Stardust1

[dweller25]

On 18/12/2022 at 22:24, IB20 said:

What do people recommend for magnification and EP ranges for BV use (I seem to have fairly close IPD)?

I also have a close IPD and wear glasses so here is my setup….

Baader MK V binoviewer

1.26 and 2.6 glass path correctors

Baader Zeiss prism.

Plus pairs of….

Celestron 26mm Silvertop Plossls (circa 1985)

Tal 25mm Plossls

Televue 20mm plossls

Fujiyama 18mm Orthoscopics

Vixen LV 15mm

Pentax XF 12mm

SVBONY 10mm ultra flats

The 26mm’s gave me a memorable view of M31 last year through a Mewlon 180, the contrast and sharpness was superb.

I mostly observe planets between x175 for Jupiter and x220 for Mars.

The Moon at x80 is razor sharp.

[JTEC]

With TEC140: Baader Mk V with either 1.25 or 1.75 GPC or, more usually, 2” Televue X2 Powermate.  1.25” or 2”  Baader prism diagonal.  Eyepieces: 18mm Tak LEs, 12.5, 9 and 6mm Tak orthos.  The 18s and 9s are most used.  11mm TV Plössls also gave excellent results - 8mm TV Ps. also very good but a bit too tight on eye relief for comfort.  Pair of 28mm Edmund RKEs work well but don’t see much use. 
Embarassed to say that I’ve never accurately determined the mags these combinations give - pretty sure it differs from what a simple calculation suggests because of the variations in spacing and the 1.7 GPC yielding more like 1.5.  I’m happy with modest fields of view. 
The advantages of the bino in terms of lunar and planetary detail perceived and circumventing the effects of floaters have to be experienced to be appreciated, I think. Roland Christen advised going no lower than 10mm eyepieces.  Certainly, the 6mms feel awkward to me.  The 9mm Taks are my favourite for lunar and planetary, yielding, depending on the negative lens used ahead of the bino, between about x140 and x220, the lower end of the range probably best suited to Jupiter and the higher great for the Moon. On DSOs, I’ve unforgettable memories of peering into the depths of M42 with the 18mmLEs; there perhaps a little more width would have been even better!