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Eyepiece set for Denk II with Power Switch

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#1 Squanto

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Posted 22 February 2021 - 07:26 PM

Hey guys I just got myself some used Denk II binoviewers with the Power Switch along with the multi-purpose OCS to use with my TS Photoline 130 Refractor with the 3.7” focuser.

So far the only pair of eyepieces I have for the Denks is the 18mm Baader Classic Orthos. My question is what set of eyepiece pairs would you guys recommend to own with the PxS that’ll cover most of the spectrum of useful magnifications.

Would the Baader Hyperion Zooms be my best/cheapest long term options for Lunar/planetary and some DSOs observing?

I live east of Portland OR where we are currently 4 months into out 8 month rainy season so I won’t have very many options to test out the 18mm BCOs to get a real feel for them. Just trying to get some insight ahead of time I guess. My skies are about bortle 6 and I do most of my observing from the driveway. Thanks in advance!

#2 RedzoneMN

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Posted 22 February 2021 - 07:31 PM

24 Panoptic

Baader zoom

20mm TV Plossls

KK Ortho's  are all good choices. 


Edited by RedzoneMN, 22 February 2021 - 07:49 PM.

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#3 Reid W

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Posted 22 February 2021 - 08:23 PM

You'll want the Baader zooms.  That or 8-14 ortho pairs.

 

Be mindful that as power increases, exit pupil shrinks and merging becomes more of a challenge.   

 

With lunar, just pile on the magnification.  



#4 Jeff B

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Posted 22 February 2021 - 10:53 PM

A pair of eyepieces that will work well with all three power switch settings.

 

From my own direct experience, here are pairs that work well for me at all power switch settings with no excessive eye relief or black outs/kidney beaning:

 

Denk 21MM LOA Neutrals

Celestron 26MM and 22MM Silver Tops

Edmund 28MM Plossls

APM 18MM and 15MM UFF

Brandon 24MM

Celestron 30MM and 35MM Ultimas or other brand clones

Clave 25MM and 20MM Plossls

Zeiss PL10x/23 444036-9000 microscope eyepiece

Baader 18MM Classic orthos

 

Many wide field eyepieces, like the TV 24MM Pans, just don't work well for me at the higher power switch settings.  Of the above, I spend a lot of my time with the Denk 21 LOA Neutrals, 28mm Edmund Plossl, Celestron Ultimas and APM UFF.  On the cheap, it would be hard to wrong with, in fact you will get excellent results with,  your 18mm orthos and a pair of 28mm Edmund Plossls.  A bit more money and I highly recommend the Denk 21MM LOA Neutrals.

 

I also strongly suggest you try using the Multipurpose OCS cell threaded in to the Denk I's 2" nosepiece as per the attached photo as it will give you the lowest possible mode, ~ 1.25X, and more range of magnifications and focuser travel when combined with putting the OCS in the diagonal nose piece.

 

Enjoy your viewers!!

 

Jeff

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  • Denk II, OCS in Nosepiece.jpg

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#5 Squanto

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Posted 22 February 2021 - 11:58 PM

A pair of eyepieces that will work well with all three power switch settings.

 

From my own direct experience, here are pairs that work well for me at all power switch settings with no excessive eye relief or black outs/kidney beaning:

 

Denk 21MM LOA Neutrals

Celestron 26MM and 22MM Silver Tops

Edmund 28MM Plossls

APM 18MM and 15MM UFF

Brandon 24MM

Celestron 30MM and 35MM Ultimas or other brand clones

Clave 25MM and 20MM Plossls

Zeiss PL10x/23 444036-9000 microscope eyepiece

Baader 18MM Classic orthos

 

Many wide field eyepieces, like the TV 24MM Pans, just don't work well for me at the higher power switch settings.  Of the above, I spend a lot of my time with the Denk 21 LOA Neutrals, 28mm Edmund Plossl, Celestron Ultimas and APM UFF.  On the cheap, it would be hard to wrong with, in fact you will get excellent results with,  your 18mm orthos and a pair of 28mm Edmund Plossls.  A bit more money and I highly recommend the Denk 21MM LOA Neutrals.

 

I also strongly suggest you try using the Multipurpose OCS cell threaded in to the Denk I's 2" nosepiece as per the attached photo as it will give you the lowest possible mode, ~ 1.25X, and more range of magnifications and focuser travel when combined with putting the OCS in the diagonal nose piece.

 

Enjoy your viewers!!

 

Jeff

This is some good info Jeff! I have actually been eyeing the 28mm RKEs (pun intended). I emailed Edmund Optics to see when they’ll be back in stock and as of today they are saying they should be back in stock mid April. I’ll be picking me up a pair. 
 

The Denk 21 Neutrals seems like they’re fairly priced for the performance. For the price of a pair of neutrals I could pick up some used D21 Denk eyepieces and I was wondering if they might be just as effective or better than the neutrals considering the D21s are “high quality”

 

I have the Astro-Tech 2” mirror diagonal that I’ll be using the BVs with and read up on the manuals available on Denkmeier website to properly place the OCS for use with refractor. Based on the manual it says to place it in front of the diagonal on the nosepiece. Is that the same thing you’re talking about? 


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#6 faackanders2

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Posted 23 February 2021 - 12:08 AM

24mm Panoptics for widest TFOV in 1.25".68 AFOV 

LOA 21mm 3D for pure fun!


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#7 Jeff B

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Posted 23 February 2021 - 10:15 AM

Squanto, you don't need to spend on big buck eyepieces to get big thrills with bino-viewers.

 

The RKE's are great at low power because of that floating space field in front of you effect that they are soooo good at.  However, they are a pain for me at higher power switch settings due to excessive eye relief, forcing me to be seated, with my head in a vice, otherwise I get severe blackouts.  The Edmund 28mm Plossls give you a nice bit of the floating effect, but are however, much more "barlow friendly" than the RKEs.  Best option of course, is to have both pairs.  grin.gif

 

I love the Denk 21MM Neutrals and I kept them and sold my older Denk 21s....with a small bit of money to spare.  In the context of my refractors, the older Denk eyepieces are slightly better corrected in terms of lateral color out towards the edge but for deep sky that is invisible to me.  The older ones are, however, much heavier with a fatter upper body which did not work so well with my IPD.  The Neutrals are great all purpose, high end eyepieces which I use a lot for both deep sky and solar system viewing.  They are a hoot for wide field lunar vistas.  And, of course, they were specifically designed to be used with Denk viewers and power switches.  Now the cheapest way to score new Neutrals is to get the LOA 3D system (which is one 21mm with the 3D array and one Neutral) and get an extra Neutral at a significant discount.  The 3D system is major fun for me on deepsky at a dark site...but it is expensive.

 

You can place the OCS element either in front of the diagonal or after it, on the nose of the viewer as in my picture.  Placing it on the diagonal nose will give you the highest power for each of the switch positions and greatest focuser out-travel for each switch position.  Placing the OCS on the viewer's nose piece, will give you lower power and less focuser out-travel for each switch position than with the the OCS on the diagonal's nose piece.  In fact, with the OCS on the viewer's nose piece with the switch in the low power mode, you will more than likely have to rack the focuser in relative to where you would focus in mono-vision sans-viewer.  This flexibility is one of the reasons I like the Denk Power Switch systems so much.  Try it both ways, experiment and have fun!

 

Jeff


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#8 Squanto

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Posted 23 February 2021 - 12:47 PM

Thank you for taking the time to respond in detail Jeff! I’ll definitely try placing the OCS both ways to see the results it gives me.

As far as the eyepieces go, I think the best thing for me is waiting to try the 18mm BCOs I already have to get a feel for the views I can get before pulling the trigger on any new eyepiece sets. I’ll look into the Edmund 28mm Plossls along with some of the others you mentioned.

Also appreciate everyone else’s input on this subject. I’ll take all the advice I can get as I’m still very new to this hobby!

#9 Russ S.

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Posted 23 February 2021 - 01:27 PM

Smart to start with the EP's you already have, you can see if that FL works well with the PxS and corresponding magnifications and go from there (especially if you play with the OCS placement which might further effect things). And don't think you necessarily need anything fancier than plossls, especially for Luna and planets. The last time I used my refractor and Denks a week ago, the best view of the moon I got was with my 15mm TV plossls. They're an inexpensive way to experiment with FL's before dropping big money on wider FOV's, the views should be excellent, and eye relief should be very comfortable at the sizes you're considering. I'm also not fond of huge heavy EP's when binoviewing, often with IPD issues, but that's a personal thing. Good luck, and have fun with your search, remember it's a hobby. wink.gif


Edited by Russ S., 23 February 2021 - 01:44 PM.

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#10 Squanto

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Posted 23 February 2021 - 04:57 PM

Smart to start with the EP's you already have, you can see if that FL works well with the PxS and corresponding magnifications and go from there (especially if you play with the OCS placement which might further effect things). And don't think you necessarily need anything fancier than plossls, especially for Luna and planets. The last time I used my refractor and Denks a week ago, the best view of the moon I got was with my 15mm TV plossls. They're an inexpensive way to experiment with FL's before dropping big money on wider FOV's, the views should be excellent, and eye relief should be very comfortable at the sizes you're considering. I'm also not fond of huge heavy EP's when binoviewing, often with IPD issues, but that's a personal thing. Good luck, and have fun with your search, remember it's a hobby. wink.gif

Man I’m so jealous. A week ago all we got here is a bunch of snow, as if the rain wasn’t bad enoughbawling.gif

 

Im of the same mindset. I think I can totally get by with modest eyepieces for now at least while I’m still learning. That way when I finally do upgrade to premium eyepieces I’ll be able to fully appreciate them? ‍Maybe I just don’t know what I’m missing out on considering I haven’t tried any of the fancy TV eyepieces. The best eyepiece I have in my collection is the 24ES68 and I do prefer that one over some of the others I have in my arsenal. Time will tell I suppose. Thanks! 


Edited by Squanto, 23 February 2021 - 05:00 PM.


#11 Russ S.

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Posted 23 February 2021 - 06:03 PM

Good plan, and while experimenting with prime EP's is expensive, it's twice as expensive with a BV. Your 24ES68 is no slouch, probably a Pan clone, and the real thing will only be slight but nice improvement.  If you really like it you can then upgrade for the long haul, but maybe you'll decide you want the 19 instead, or something else. As others always point out, star parties and clubs are a great way to learn about the hobby, and a great opportunity to try other's premium EP's before taking the 2X plunge. waytogo.gif



#12 Squanto

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Posted 24 February 2021 - 12:04 AM

Quick question for for those of you that use your BVs for Lunar observing....is there any need for an ND filter assuming that only “half” the brightness goes to each eye vs all the brightness into one eye with mono?

#13 Moon-Watcher

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Posted 24 February 2021 - 01:21 AM

Hey Squanto,
I have the exact same setup. 24mm Panoptics are perfect. And as for lunar viewing, be prepared for an out-of-body experience. The TS130 f7 triplet coupled to the Denk with 24mm Pans will make you gasp at the moon. No ND filters required.

#14 Squanto

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Posted 24 February 2021 - 01:57 AM

Man you’re getting me stoked! I tested out the BVs on some distant trees during the day and already I was blown away by the amount of detail I could see with both eyes vs mono.

As far as 24 Pans go I think I might end up there eventually but for now I need to work with what I got. Can’t waste all my money on a set of eyepieces just yet haha!


Edited by Squanto, 24 February 2021 - 01:59 AM.


#15 Reid W

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Posted 24 February 2021 - 07:56 AM

I'll second the idea of getting another ES24.

 

I have the 20mm ES 68s and they are superb.  The 24s should be too.



#16 REC

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Posted 24 February 2021 - 02:14 PM

24mm Panoptics for widest TFOV in 1.25".68 AFOV 

LOA 21mm 3D for pure fun!

I had a pair of the LOA 21mm in my Denk II and they where a blast. Notable was M42, double star cluster, bright open star clusters and Globs. Also some of the better known Nebula was fun too! I was mainly using them in my 10" Dob and my 8" SCT.


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#17 Squanto

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Posted 25 February 2021 - 05:05 PM

So I got a break in the clouds last night and was able to have first light with my Denk II w/PxS for about an hour plus. “WOW” is an understatement. The moon was super crisp with lots of detail! I love these BVs! 
 

The 18mm BCOs worked flawlessly with all three PS settings. At lowest power the whole moon fit into the AFOV nicely. The rest of the settings were nice too albeit slightly dimmer.  I can definitely see the appeal for eyepieces with wider FOV! As a matter fact I got a pair of Denk LOA 21mm Neutrals on order grin.gif

 

I did get a chance to play around with the placement of the OCA as suggested by Jeff and I found that the only way I was able to get focus in all three PS settings was to have the OCA in front of my Astro-Tech 2” diagonal nosepiece with room to spare of draw tube travel both ways. Placing the OCA before the diagonal as pictured above did not work at any magnification setting. Mind you I do have the 3.7” Deluxe focuser on my TS 130 f/7 Triplet if it matters. 

 

Now I’m wondering if there would be any benefit to getting the BV to mate with the Baader T2 90 prism diagonal to shorten the light  path and perhaps not have to use the OCA? Any disadvantages? I am aware that I’d need a special adapter and all so I’m just wondering at this point. If everything works the way it is with my current setup should I just leave it as is? Am I having any sort of aperture loss with this configuration? Reason why I’m asking is because I’d like to have a separate diagonal that’s always attached to the BVs so I could use my current diagonal for mono in case I wanted to observe some faint DSOs in the same night. 


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#18 Jeff B

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Posted 26 February 2021 - 12:08 AM

Yesssssss!

 

Another hobbyist infected with bino-viewing.  Yessssss.

 

I'm a little surprised you could not get to focus with any of the switch positions with the OCS element in the viewer's nose piece.  I would wager then that with the 18mm BCO's in mono-vision with your 2" diagonal, you have very little focuser in-travel left.  How much do you have left?   Also, my 18mm BCO's and most of my orthos for that matter, require a good 10 to 12mm of in-travel to reach focus relative to a typical Plossl and the Denk 21mm Neutrals (which you will LOVE).

 

"Now I’m wondering if there would be any benefit to getting the BV to mate with the Baader T2 90 prism diagonal to shorten the light  path and perhaps not have to use the OCA?"

 

The real benefit of a bino-friendly refractor, IMO, is the ability to get the maximum true FOV available in the 1.25" format eyepiece.  I consider it a special niche configuration but a very nice one too.  One look at the double cluster, M31, M42 with the entire loop and other wide field stuff and you'll understand completely.  But you have to be able to "get there", meaning to focus without the OCA element.  Again, it comes back to how much residual in-travel you have available with your current 2" diagonal and your chosen low power eyepieces which will be your Neutrals.   If it's less than about 2.5 inches, even with the prism diagonal's short path length, you most likely cannot "get there".  

 

Now you don't need an APO for outstanding low power bino-viewing.  A high quality F5 or F6 achromat can be just as effective as the power is so low, the color error is typically invisible or subjectively minor.  So, you end up with a niche telescope....and an excuse to buy another telescope. grin.gif

 

Another option: If the nose piece for your Astro-Tech 2" diagonal unscrews, try screwing the OCA directly into the diagonal's body.  That shortens its distance from the focal plane and reduces magnifications a bit.

 

I'm glad you're enjoying the experience.

 

Jeff


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#19 Moon-Watcher

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Posted 26 February 2021 - 12:54 AM

Yesssss. His journey to the Bino side is almost complete....now strike down your thoughts of cyclops vision with all your squinting and join us, wide eyed and wide field to view the universe with both eyes.....
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#20 Jeff B

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Posted 26 February 2021 - 10:00 AM

You don't know the POWER of bino-viewing!  Together, with both eyes, you can rule the galaxy!  evillaugh.gif



#21 RedzoneMN

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Posted 26 February 2021 - 10:22 AM

Also, scrunching up your face gets tiresome after a while. 



#22 Squanto

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Posted 26 February 2021 - 12:24 PM

Also, scrunching up your face gets tiresome after a while. 

“Not having to scrunch my face will help alleviate premature wrinkles and keep me looking younger for longer” ....At least that’s the argument Ill present to the CFO once she finds out how much I’ve spent on this setup with eyepiece pairs lol.gif

Can’t argue that! 


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#23 Squanto

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Posted 26 February 2021 - 12:30 PM

Yesssss. His journey to the Bino side is almost complete....now strike down your thoughts of cyclops vision with all your squinting and join us, wide eyed and wide field to view the universe with both eyes.....

I hearby renounce my squinty-eyed ways and fully embrace this new glorious journey into the cosmos with both eyes wide open!   bounce.gif


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#24 Squanto

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Posted 26 February 2021 - 12:48 PM

Jeff B

Your enthusiasm only helps fuel my excitement! 
 

The last thing I need now is to go out and buy another telescope! Haha I don’t think I’d be able to talk my way out of that one with the CFO!

 

“I would wager then that with the 18mm BCO's in mono-vision with your 2" diagonal, you have very little focuser in-travel left.  How much do you have left?”

 

I have not been able to try the 18mm BCOs in mono yet to see what kind of in focus travel I have left. I’ll have to play around with it when I get a chance. Once I get some measurements I’ll try placing the OCA directly to the body of the diagonal and see what kind of changes I get. 


Edited by Squanto, 26 February 2021 - 12:51 PM.


#25 faackanders2

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Posted 26 February 2021 - 06:19 PM

So I got a break in the clouds last night and was able to have first light with my Denk II w/PxS for about an hour plus. “WOW” is an understatement. The moon was super crisp with lots of detail! I love these BVs! 
 

The 18mm BCOs worked flawlessly with all three PS settings. At lowest power the whole moon fit into the AFOV nicely. The rest of the settings were nice too albeit slightly dimmer.  I can definitely see the appeal for eyepieces with wider FOV! As a matter fact I got a pair of Denk LOA 21mm Neutrals on order grin.gif

 

I did get a chance to play around with the placement of the OCA as suggested by Jeff and I found that the only way I was able to get focus in all three PS settings was to have the OCA in front of my Astro-Tech 2” diagonal nosepiece with room to spare of draw tube travel both ways. Placing the OCA before the diagonal as pictured above did not work at any magnification setting. Mind you I do have the 3.7” Deluxe focuser on my TS 130 f/7 Triplet if it matters. 

 

Now I’m wondering if there would be any benefit to getting the BV to mate with the Baader T2 90 prism diagonal to shorten the light  path and perhaps not have to use the OCA? Any disadvantages? I am aware that I’d need a special adapter and all so I’m just wondering at this point. If everything works the way it is with my current setup should I just leave it as is? Am I having any sort of aperture loss with this configuration? Reason why I’m asking is because I’d like to have a separate diagonal that’s always attached to the BVs so I could use my current diagonal for mono in case I wanted to observe some faint DSOs in the same night. 

If you ordered a pair of neutral LOA 21 why wouldn't you order the one extra LOA21 3D to have fun looking in 3D.  It is definitely an exciting WOW factor.  Works best on Milkyway and objects with lots of stars.

 

P.S.  Just don't look at the bright moon or you figure out how it works, and once you gain that knowledge you can't unlearn it.


Edited by faackanders2, 26 February 2021 - 06:26 PM.



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