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nyc_nurse
sage
Reged: 07/29/09
Posts: 254
Loc: nyc
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I met a fellow CN'er on Tuesday night at a dark site and he was kind enough to let me play with his WO binoviewer. I always considered BV'ing but didn't know what the fuss was about until that night. Just one night of using 2 eyes has spoiled me - much more relaxing and natural. I've been reading as many of these BV'ing threads as possible but have so many questions on how to get started.
I have a standard TV-102 (non imaging version) with Everbrite 2-inch diagonal. It looks like I have a good BV EP's with my 24 Pan and 13 Nagler (just have to buy another pair). The WO BV couldn't come to focus without the 1.6X barlow. Which other models should I look at? How does the Televue and Denk models stack up? Any insight or links would be appreciated. Thanks.
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Sam P.
www.agirlandaguy.blogspot.com
Pentax 7X50
TV-102 APO w/ (Starbeam - on backorder  )
Ash Gibraltar w/ SkyTour DSC
NZ3-6, N9T6, N13T6
TV 20 Plossl
Pan 24, 35
Pentax XW10, XW14
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Bowmoreman
Post Laureate
Reged: 09/11/06
Posts: 4149
Loc: Bolton, MA
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Sam, I'm going to "lurk" on your thread as well, as I'm trying to decide what I want to do to best get into BV'ing as well...
I'm thinking Denk or Earthwin (you may want to add them to your short list) is the route I want to go... I probably don't want to go the WO or other (cheaper) BV system route. I'm one of those guys who always regrets not buying higher up the "food chain" so to speak. I may also look at the TV system, but I sure like the Denk and Earthwin system of instant power adjustments (cuts down on the number of EP pairs!)...
I want to make sure that whatever I get will work in both my 11" SCT and my 10" dob... that's the complication in my case.
Clear enough skies
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Dave
Imaging: MI-250+ADM/SBS/Optec Libra: C11Hyperstar,TMB80SS
Visual: XT10i RTP
EP: 31T5,22T4,17T4,12T4,13Ethos,10XW,8Ethos;2x Powermate,Paracorr, 1.6X Antares, Hyperion8-24Zoom
Cameras: Mallincam Color Hyper Plus, QHY8
Guider: SBIG STV eFinder
Key Add-ons: Gerbings Heated clothes, WilderSkiesObservatory(BYO#90), Speco 9"Monitor
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NoiseJammer
sage
Reged: 09/16/07
Posts: 235
Loc: Gone walkabout
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Sam, achieving focus without a Barlow is dependent on the scope and (to a lesser extent) the binoviewer / diagonal combination. Denks and the TV Binovue typically need 220mm of available in-focus when mounted on a 2" diagonal, the Mk V is somewhat less.
The obvious thing to do is measure how much in-focus your scope has. This is easy when the moon is bright - just remove the eyepiece & diagonal, wind the focuser in as far as it can go and use your hand to find focus.... If you have less than around 220mm clear you will either have to use a Barlow or shorten the tube. I had a quick look on the web - it seems the imaging version is about 5" shorter than the normal one (and it's intended to achieve focus with binoviewers.) Maybe TV would sell you a replacement tube...
Fwiw, a short tube is nice for cruising the sky at low power (provided your sky is dark enough.) The widest true field of view you can expect will be around 1.8 degrees.
Clearest
Bruce, Toronto
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178 square inches of mostly shiny glass, one biph
... and way, way too much light polution.
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planet-beaver
sage
Reged: 11/03/08
Posts: 290
Loc: Middletown, NY
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This is why I usually recommend the WO binoviewer because they add only 3.9" of light path vs 5.1" for Danks and Wins. Many people will reach focus with Chinese binos but not with Danks. I currently have a set of WO but plan on buying Earthwins for my Cat telescopes. As most people know, the cats will reach focus on all binoviwers without adding any OCAs.
I did a review some time ago comparing Danks Standard to WO and found WO had a better light transmission with brighter images. The Danks have brown tint that makes everything darker. Since we are already splitting the light in half, making it even darker is not good. Unfortunately, the quality of WO makes them useless at high powers x200+. This is why I need better set for my CATs. I will keep my WO set for low power dob use.
Few photos showing just how darker the Danks are (top set).
I returned the Danks.
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Garrett Gemini 30x100
Barska 30x80
Garrett SS 15x70
SkyMasters 15x70
Regal LX 10x42
Nikon 7x35 Action Extreme
Orion XT8 dob
C11
LX200 8"
WO Binoviewers
Edited by planet-beaver (11/20/09 11:14 AM)
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nyc_nurse
sage
Reged: 07/29/09
Posts: 254
Loc: nyc
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Hi Dave. I'm with you when it come to getting something optimal the 1st time around so you don't have to upgrade later. However, the premium BV - Denk II and Mark V - are a lot of money to spend without having much BV'ing experience. I too want to be able to use the BV with my TV-102 and a future big dob. I've been looking at the Denk II with power-switch diagonal. Haven't read much about Earthwin but I'll look into it. Thanks.
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Sam P.
www.agirlandaguy.blogspot.com
Pentax 7X50
TV-102 APO w/ (Starbeam - on backorder )
Ash Gibraltar w/ SkyTour DSC
NZ3-6, N9T6, N13T6
TV 20 Plossl
Pan 24, 35
Pentax XW10, XW14
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nyc_nurse
sage
Reged: 07/29/09
Posts: 254
Loc: nyc
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I'll try that on the next quarter moon. I think a call to TV and Denk are in order too. I'm sure they've gotten many inquiries into the TV-102 and BV'ers. Thanks.
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Sam P.
www.agirlandaguy.blogspot.com
Pentax 7X50
TV-102 APO w/ (Starbeam - on backorder )
Ash Gibraltar w/ SkyTour DSC
NZ3-6, N9T6, N13T6
TV 20 Plossl
Pan 24, 35
Pentax XW10, XW14
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nyc_nurse
sage
Reged: 07/29/09
Posts: 254
Loc: nyc
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Thanks for the photo's Chris. I see what you meant by the difference in color tone. Didn't think it was going to be that obvious. Wonder if that's an indication of less light-throughput or just a color tonal difference? My TV EP's are already a bit warm so I wouldn't want to introduce any more into the light path. Thanks.
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Sam P.
www.agirlandaguy.blogspot.com
Pentax 7X50
TV-102 APO w/ (Starbeam - on backorder )
Ash Gibraltar w/ SkyTour DSC
NZ3-6, N9T6, N13T6
TV 20 Plossl
Pan 24, 35
Pentax XW10, XW14
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johnnyha
Carpal Tunnel
Reged: 11/12/06
Posts: 1539
Loc: Sherman Oaks, CA
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Somehow I knew you would be over here soon Sam. 
You cannot, IMHO, do better than the Denk IIs. Solid perfection. Rather than try to achieve focus without a corrector, which limits you to one magnification per EP set, I would highly recommend getting the Denk II with 3-way Power Switch with SR attachment for your diagonal. The 3-way Power Switch will really open up your two EP selections, providing six magnifications from wide angle to super planetary goodness. As you may have noticed, with two eyes everything looks bigger too! However, the 3-way mag switch cannot be used without a corrector in front of the diagonal. You can do two things - screw the included Denk OCS (mild barlow) corrector onto the front of your diagonal, where you will be able to achieve focus in all positions, or - better option - get the Denk SR attachment, which is an even milder barlow corrector that screws into the front of the diagonal but is recessed into the diagonal itself, bringing the lens closer to the EP and therefore giving you something like 1.3x or so in the widest field setting.
Another danger of using BVs without a corrector somewhere in the path is they may very well vignette in a fast scope, probably not your TV102 but in the 32" F/3.2 dob you will be carting around next year.
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Johnny
Spicewood, TX
Sherman Oaks, CA
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johnnyha
Carpal Tunnel
Reged: 11/12/06
Posts: 1539
Loc: Sherman Oaks, CA
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Oh I forgot another option is to get a regular Denk II and a Denk Power Switch diagonal. The diagonal can then be used to give 3 magnifications for all of your EPs.
If the 3-way mag switch sounds sketchy, it isn't. There is absolutely no degradation of image that I can see when bumping up the mag.
Oh, as for the Denk II color tone in the photos -OMG - they actually have a slightly different tone on EACH side, which promotes a 3 dimensional effect when viewing through them. Kinda like 3d glasses. Look at the photos again - the right side is reddish and the left is bluish. get it? It's a trade secret so don't tell anybody. Trust me, it works like a charm and it is part of the magic of Denk IIs. Call Russ at Denkmeier he'll answer any questions you have. I don't have any stake in this BTW I just have had nothing but good experiences with this product, it exceeeded my every expectation.
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Johnny
Spicewood, TX
Sherman Oaks, CA
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nyc_nurse
sage
Reged: 07/29/09
Posts: 254
Loc: nyc
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Thanks for the info Johnny. From all accounts the Denk II seems phenomenal. I'm leaning towards the Denk II with power-switch diagonal (even though I would loath not using my Everbrite) since a big dob purchase is definitely in the near term horizon for me.
If the TV-102 has enough travel I like the R2 diagonal.
R2 diagonal w/dielectic coating - $720
Denk II BV - $900
Total - $1,620
Vs the Denk II Super-system for refractor - $1,300
$300 for a diagonal is not bad but $720  Jezz, but I have to remind myself that it's not just a diagonal. Hum, wonder if any dealer around here has these in stock so I can take a peek.
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Sam P.
www.agirlandaguy.blogspot.com
Pentax 7X50
TV-102 APO w/ (Starbeam - on backorder )
Ash Gibraltar w/ SkyTour DSC
NZ3-6, N9T6, N13T6
TV 20 Plossl
Pan 24, 35
Pentax XW10, XW14
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johnnyha
Carpal Tunnel
Reged: 11/12/06
Posts: 1539
Loc: Sherman Oaks, CA
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Sam - D'oh! I'm gonna backtrack here and suggest you NOT get the diagonal power switch. I just realized why I'm glad i didn't - the big dob doesn't use a diagonal!! With the bino PowerX switch as opposed to the diagonal PowerX switch, you have the three mags always available anytime you use the binos, whether in a big dob or your TV Everbrite diagonal. And trust me, you are gonna want those power changes in your big dob, it is really nice not to have to switch the pair of EPs out too often. I had no idea the diagonals were that expensive holy cow!
Anyway the $1300 Denk II Super System is for BOTH refractors and dobs, that's the one you want.
Egads I just realized this is getting pricey! I feel like i am being a bad influence, maybe just a nice 8mm Ethos to tide you over for awhile???
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Johnny
Spicewood, TX
Sherman Oaks, CA
Edited by johnnyha (11/21/09 01:07 AM)
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NoiseJammer
sage
Reged: 09/16/07
Posts: 235
Loc: Gone walkabout
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Sam,
I have the R2 dieletric diagonal - it works but it needs about 3" of focuser travel to exploit the 1.3x - 3x magnification range.
As for selection of binoviewers... I did a direct comparison between the Denk II and the William Optics. I'm sorry to disagree with planet-beaver but there really was absolutely no comparison.
Regarding the required back focus, this is limited by the dimensions of the prisms. Although it's somewhat shorter (3.9" vs 4.5") the WO bv has a 21mm or 22mm prism which greatly restricts the unvignetted field of view and therefore the minimum magnification.
This really is a case of you pay for what you get. If you find that dropping the cash for a pair of Denk II's or a R2 diagonal is scary, be patient and they will turn up on AM.
Clearest
Bruce
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178 square inches of mostly shiny glass, one biph
... and way, way too much light polution.
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Joe Lalumia
Post Laureate
Reged: 01/24/07
Posts: 4132
Loc: Rockwall, Texas, USA
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Siebert Optics makes an OCA with only 1.25 power that permits most bino setups to come to focus in either a DOB or a refractor. Very low power OCA. Here:
http://www.siebertoptics.bizland.com/SiebertOptics-OCA.html
see ad #2
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LX90 8" LNT, SV Nighthawk & TelePOD, ETX 90, Orion XT10i, SV 80/9d, 20x80 binoculars www.texasastro.org
"The secret to creativity is knowing how to hide your sources." - Albert Einstein
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