Binoviewers and planetary observation, a short discussion.

[mike bacanin]

Have you ever wondered about going the binoviewer route for planetary observation? I thought i'd share my experiences of using binoviewers with you.

My first venture was about 4 years ago. I purchased a pair of telescope house binos. These had the set screw retaining eyepiece holders, which were individually adjustable for focus. My scope was a TMB 130 F6 apo.I'd read alot about the great views that could be had, but decided to go gently money wise to test the waters. I used 12.5 tak le's and a barlow. the moon was superb i thought,very relaxed viewing.Jupiter was in need of more power,so i purchased a pair of tak le 7.5's.

and then i had my first problem. i could not merge the images. I found out that this was due to the limitations of the binoviewer. they were not up to the demands of short fl eyepieces.

having decided i really liked the bino experience, i went mad and bought a pair of Denk II's with powerswitch. Wow,the difference was awesome. Russ at Denk assured me the II's would be up to high power planetary use, and they were. I decided to use the powerswitch at 3.5x and used a pair of nagler 16's.

Jupiter was stunning, i clearly recall the GRS hollow very defined and wonderful belt detail and festoons. in fact, i was able to use 4mm ep's straight through, a testimony to the superb collimation of the denks.

since then, i have used std denks in C8, C9.25 with great results.

a big plus for sct's is the long focal length, allowing fairly long focus eyepieces without the need for a barlow. naturally a std refractor or newt will need a barlow or similar corrector lens to throw the focus further out, allowing binos to come to focus.

my current setup on the Tak 128 apo will be Denk II's (en route from usa as i type) and pairs of pentax 12mm orthos, zeiss 10mm and 16mm orthos. I have a powerswitch giving x1.4 and x2.5, so should be versatile.

my advice to anyone considering bino viewing is try the experience with say a used pair first,but be aware of limitations for magnification with cheaper units.

then if you are hooked,try to buy a high end unit like denk or televue or baader.

the single biggest plus point are self centring eyepiece holders. these to me are critical for merging planetary views. set screws tend to slightly off centre the eyepieces, which can cause trouble trying to merge at moderate to high power.

i noticed that skywatcher binos have self centring holders and these would be a good starter pair.

what are the real advantages of binos for planetary? well for me, very relaxed viewing giving a better resolution of fine detail, and greater freedom from floaters, which are a nightmare in high power mono mode.

i would not recommend going less than 8 0r 9mm in eyepieces, it places big demands on the optical chain.

also eyepieces like orthos with less elements reduce glare issues on the image.

also use the best diagonal you can afford, to keep the chain strong.

a word about .965 inch orthos. you need to very carefully shim these in their 1.25 inch adapters to ensure perfect centring. i also modded my adapters to grub screws to prevent the normal set screws fouling the bino eyepiece holders, see photo.

i hope you may try binoviewing,it can be a very rewarding experience for a planetary observer.

mike

[mike bacanin]

My post is inclined towards observers seeking to get the best out of planetary binoviewing.

However you will get pleasing views with inexpensive units and decent plossl eyepieces.

maybe that will help you decide if you want to climb further up the binoview ladder, but be warned it's an expensive game!

Mike

[mike bacanin]

Eyepieces for optimum planetary binoviewing.

Good eyepieces at reasonably low used price: Televue plossls,circle T orthos, UO HD, Baader ortho, meade RG orthos. celestron ultima plossl hybrid.

If money is not main issue! : TMB supermonos, pentax smc orthos, zeiss jena orthos, Zeiss Abbe and Zeiss Abbe II, Astro physics SPL.

Televues give a warm image tone which can be good on Jupiter.

others give a purer tone, TMB's very pure and stark.

TMB have 30 degree fov

most others around 40 to 45 degree fov.

AP SPL have great eye relief about 120 to 140% of focal length,

Mike

[philsail1]

That was a very nice resume' of your experiences with "Binoviewers" Mike.

I envy you having a pair of "Denk" Binoviewers! The views must indeed be superb.

I can vouch for the lovely views when looking at the Moon and Planets. I bought a pair of "cheap" "Astro Engineering" Binoviewers, and use them reguarly on my 8" Orion Optics f4.5 Newtonian, and 90mm Skywatcher Maksutov. (I have to remove a section of the Newts focuser to get that "in" focus).

Best wishes

philsail1

[PaulC-I]

Hi Mike,

Pleasure to hear your experience of the denks. I have the Denk II's and can testify to their excellent quality, after using a pair of the cheaper units (Which were a WOW for the first time bino experience).

I'm using the 10 & 16 Jena's with great results. I can also recommend the Denk D14's (Perform as the awsome Pentax XW's do), Pentax XF 12's and of course the 19 Pan's.

Having had the pentax smc ortho and supermonpcentric I can confirm that these eps are worthy contenders but with advantage of a wider field of view.

I use the denks in an F10 5" refractor as well as a 12" F6.3 dob (soon a 14" Jim Hysom truss dob)

Also a Skywatcher 180 promak. And I agree with you totally thet the Mak's long focal length makes viewing with a binoviewer a very relaxing experience with being able to use longer focal length eyepieces.

I have an opportunity to upgrade? to the Baader V but these things are always a gamble without being able to try before you let existing equipment go!

I guess us stargazers (gear freaks!) can never quite settle!!

I look forward to hearing your experience of the Denk II's.

Thanks for your great report

Paul

[mike bacanin]

Hi Phil and paul,

Thanks for your comments.

The cheaper units give good views for very little money, especially when bought used.

as i mentioned, they allow you to judge if binoviewing is for you.

the cost of doubling eyepieces is a big thing to consider.

but yes, the wow factor is big!

i think lunar views for the first time are quite stunning, and the cheaper units perform very well on lunar,giving an almost "being in orbit" effect, wonderful!

i hope this little thread may encourage a few to give it a try, and you can do so for maybe around £100 with a used unit and a pair of used eyepieces.

paul, i'll report when the denks arrive and i get first light, hopefully on jupiter if possible. I'm sure the Baader V will be superb, let me know how it all goes.

mike

[Darren B]

I have the Stellavue BV3 binoviewers which came with a pair of 23mm eyepices. fortunately I can use this without the OCA with my 80mm telescope which is great for low power viewing. For planetary and lunar, I stick an Ultima x2 barlow on the end of it. I enjoy viewing the moon with this set up.

[mike bacanin]

Hi Darren,

thanks for giving details of your setup.

The BV3's from what i've read on cloudy nights appear to be a nice binoviewer. As you say, you can use a good barlow instead of a dedicated OCA.

hope you have some great views!

mike

[Telescope40]

Hi all. Bit baffled by a couple of comments on Binoviewer threads which indicate the magnification "racks up" if u use binoviewers .

I have a pair and have noticed this effect. Any rule of thumb to calculate the relevant magnifications. Looking to buy a pair of new ep's but don't want to overdo the power. Using an ED80 and an F10 Lx90. Guess I'm missing something but thats nothing new.

Thx John

[gfletcher]

I have noticed the same effect.

I have a Revelation Binoviewer and when using 25mm fl eyepieces with the 1.6X Magni-Max i assumed this would give a magnification of approx X38 when used on a 600mm fl telescope.

It appears to be much greater than this !!

Am i calcualting incorrectly ?

Graham

[GazOC]

i've noticed this on my set I use with a x2 Televue barlow and I've always put it down to (rightly or wrongly!) the fact the Barlow is further away from the eyepiece than it normally would be so increasing the magnification factor.

[mike bacanin]

Gaz, i believe that is correct. The bino's light path is responsible for the extra amplifying effect. Its amazing how big a bino image looks at even modest powers!

Mike

[Izar]

The information giving in this link seems to be about right for my Antares binoviewers.

Burgess Optical Binoviewer Focus Info

Interesting about the Tele-vue powermate, has any one got such a set-up, it would be interesting to see if it does reduce the magnification?.

When I have to use a Barlow, I usually screw the lens from my Celestron 2x directly into the nose piece of the binoviewers.

All my scopes can be used without having to attach a Barlow, which really works well for DSO.

For really stupid high magnification, put the Barlow in before the diagonal, and be prepared to see the Soup dragon and Clangers in

all their glory.

[Heavens Above]

Hi Guys

I use a Baader MkV with my TMB115. I use a Astro Physics Barcon barlow to get the required mag. This barlow could have been designed for use with binoviewers as it needs more distance after the lens to reach high powers than other barlows. I use it in front of the diagonal giving me 3.2x, giving 184x with my 14mm, 206x with my 12.5mm's and 234x with my 11mm's.

Had a standard Denk before the Badder, which was a real step up in performance, like a slight but noticeable veil taken away.

My main viewing are the planets and the moon.

By the way Meade 5000 super plossl's work brilliantly with binoviewers as they need to be used with slow scopes (the barlow will make virtually any scope slow). They even outperform my Televue Plossl's!