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Equipment Discussions >> Binoviewers

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faackanders2
Carpal Tunnel


Reged: 03/28/11

New Denk Newtonian 1.2x 2" 45mm clear aperture OCS
      #5399470 - 09/02/12 11:32 AM

Just received my new Denkmeier ("Multi-purpose") Newtonia 1.2x 2" 45mm clear aperture OCS. Just need to get 45mm clear extensions. This may be the solution to my binoviewer wide FOV quest (w/ 24mm panoptics & reducer powerswitch) and no vignetting.

I plan to do a comparison with my other original 1.2x 2" OCS with the standard (35mm?) aperture. Power would be the same, but less vignetting of light cone entering the extension tubes requred to focus at such low true 1x power with reducer power switch.


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john smith
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Reged: 01/01/07

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5399486 - 09/02/12 11:43 AM

Cool, can't wait for the comparison I might have to look into one of these.
John S.


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: john smith]
      #5434244 - 09/22/12 11:23 AM

I received the 45mm clear aperture extensions and was able to do a fair comparison of 2" Multipurpose (1.2x) OCS at both original (37mm?) and new 45mm clear aperture alternatives. With my 17.5" f4.1 Discovery Split Tube Dob and 2" Denk II with 3x3 dual power switches and 24mm Panoptic eyepieces; I could just barely get the system to focus at LL (0.87x?) at the full in limit with just one extension and my Astrocrumb filter slide removed. Two extensions would have allowed others requireing mor infocus to focus, but potentially cut into the light cone more.
For comparison the 2" Newtonian (1.4x) OCS is designed to produce 1x in LL mode without any extensions required to focus, but this was not the focus of this evaluation.

At GLSG10 in Gladwin Dark skies on 9/14/12 I looked at M8 Lagoon, M31/M110 & M31/M32 Andromeda, C33(NGC6992/5)East Viel, C34(NGC6960) West Viel, and C20(NGC7000) North American. I believe I looked at them both unfiltered and with 2" Ultra block filter screwed on, since system was too long to use astrocrumb filter slide.

M8 Lagoon & Open Cluster looked good in widest LL mode, wide LM & ML modes, and medium MM & LH modes. The Ultrablock filter brought the the nebula contrast at the expense of the open cluster. I did not notice a difference in power nor brightness between 37mm and 45mm clear aperture OCS on M8 nor the cluster.

M31/110 and M31/32 looked good in widest LL mode (still not wide enogh to see all 3 in same FOV), and wide LM & ML modes (believe I could still see either two). I actually was surprised to see M110 in the 45mm clear aperture so apparent in LL power mode; whereas M110 seemed a half to a full magnitude dimmer in the original 37mm clear aperture. I did not notice a difference in power nor brightness between 37mm and 45mm clear aperture OCS on brighter M31 nor M32.

With the above benefit on M110; I only looked at C33(NGC6992/5)East Viel, C34(NGC6960) West Viel, and C20(NGC7000) North American with the 45mm clear aperture Multipurpose OCS. C33(NGC6992/5)East Viel was noticable unfiltered but showed more contrast in ultrablock at lowest LL, and low LM & ML modes. C34(NGC6960) West Viel witches broom was more noticable unfiltered and showed even emore contrast in ultrablock at lowest LL, and low LM & ML modes. I attempted to split the bright double star passing through the super nova remnat at medium MM and MH, and high HL and HM, and highest HH power modes but couldn't split it with this low power Multipurpose OCS (didn't use my higher powe Newtonian nor Multiplier OCSs). C20(NGC7000) North American was noticable in widest LL mode, and less noticable in wide LM & ML modes. I believe Ultrablock filter was required to see this and I may have just seen the brightest area around the 3 close straight stars in latin america. I did not make a comparison between 37mm and 45mm clear aperture OCS on these dimmer nebulas/super nova remnants. However I did switch to single 20mm 100AFOV and 40mm 70 AFOV eyepieces with my Astocrumb filter side with no, skyglow, ultrablock, and OIII filters; and prefered thes much brighter and wider field of views better on all the above objects; so I didn't use the binoviewers for the rest of the dark sky night.

A week or two early (9/1/12) from my slightly light polluted home skies, with only 37mm clear aperture extensions; I had my first light comparisons of Multipurpose 45mm and 37mm clear aperture OCSs, but didn't post because I didn't feel it was a fair comparison without having 45mm clear aperture extensions also. However I did look at the Coathanger, 1 day after full waning gibbous moon, M57 ring nebula, M13 Hercules, and couldn't see Viel, C14 double cluster, nor Viel. I used both 1 and two extensions with both 37mm and 45mm clear aperture Multipurpose OCS. Views were noticably dimmer with two extensions than one.

Coathanger in LL mode I could see all of hook and 4 base stars. In ML and LM modes I could see all of hook and 3 or 2 stars respectively. In MM mode not all of the hook could fit.

The bright moon looked great at 112 deg Center terminator (ref Altas of the Terminator p 170-172), and I could see Mare Crisium bottom left to Nanobu/Bliharz/Atwood trio to Langrenus to Vendelinus(Lohse,Lame, & Holden) to Petavius on top left. Note Vendelinus looked like a man with glasses and crew cut hair (turn pages 170 & 172 upside down - Lame/Lohse make the neck and Holden make the crew cut hair). Looked good at all powers LL, LM, ML, HL MM, HM, LH, MH, and HH; although highest HH power was a little fuzzy. Note looking down dob tube I could see bright moon light cone projection on 37mm OCS ring (and/or 37mm extension behind 45mm clear aperture OCS, so I couldn't wait to get 45mm clear extension tubes for a fair comparison).

M57 Ring nebula in LL mode was brighter in 45mm clear aperture than in 37mm.

M13 Hercules cluster looked like a fuzzy cluster with no detaill in all powers LL, LM, ML, HL MM, HM, LH, MH, and HH of the low power Multi purpose (0.7x-1.2x-?x)OCS. I would have been able to see lots of detail it I used the higher power Newtonian (1.0x-1.4x-3.3x) or Multiplier (?x-1.8x-?x) OCSs; although with the Multiplier OCS I wouldn't really be able to use the highest 3 powers of the 9.

For those that don't recall my system has 3x3=9 powers with the power switches, plus 3 OCS powers (the 45mm clear aperture has same power or 37mm Multipurpose OCS), and two eyepiece pairs; for a combined total of 3x3x3x2=54 power options with both eyepieces (or 27 power options per eyepiece).

Clear skies to all of you!


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5436874 - 09/23/12 08:02 PM

In conclusion if you have a Newtonian and Denk II with Newtonain OCS and want a wider view than this provides; the MultiPurpose OCS and reducer power switch will provide wider views (but MultiPurpose OCS will require infocus extensions). To avoid/minimize vignetting or intrusion into the light cone, opt for the new 45mm clear aperture MultiPurpose OCS (vs. the standard 37mm clear aperture MultiPurpose OCS). Id does help on the dim DSO objects when wanting the widest possible views.

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faackanders2
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Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5462931 - 10/09/12 09:51 PM

Anyone else take the plunge?

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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5469959 - 10/14/12 03:05 PM

Mike Harvey has seperate note praising new 45mm clear aperture OCS even more.

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Mr. Bill
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Reged: 02/09/05

Loc: Northeastern Cal
Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5485533 - 10/23/12 03:56 PM

So I gather from above that the OCS-A45 will give better off axis illumination even with f/4 systems.

It still seems the ultimate limiting factor is the 26mm clear aperture and this will vignette even f/6 lightcones which means less than 100% effective aperture.



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johnnyha
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Reged: 11/12/06

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Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: Mr. Bill]
      #5485661 - 10/23/12 05:03 PM

Bingo! It will vignette the lightcone only if you don't do the math and use a 1X reducer. With a 1.7X OCS on a long extension, then there will probably be no problems. A 2X Powermate/T-ring works perfectly at any f ratio.

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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: johnnyha]
      #5498791 - 11/01/12 12:26 AM

Additional focal reducer power switch:
0.87x barlow power with Multi-Purpose (1.2x/1.8x/2.3x) OCS at lowest power.
1.0x barlow power with Newtonian (1.4x/2.0x/2.5x) OCS at lowest power.
1.8/1.4 x estimate barlow power with Multiplier (1.8x/2.6x/3.2x) OCS at lowest power.

With my 3x3 dual power switches and Newtonian OCS I estimate I have the following 9 barlow powers:
1.ox LL, 1.4x LM, 1.43x ML, 1.79x HL, 2.0x MM, 2.5x HM, >2.5x MH, 3.2x MH, and 3.3x HH
Russ would never confirm these except for lowest and highest power.
My other two OCSs result in different 9 sets of powers TBD, but I tend to enjoy the lower powers more with wider clearer views, and rarely use the higher (fuzzy view) powers.


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5573083 - 12/15/12 07:53 PM

Anybody else buy the 1.2x 2" 45mm clear aperture OCS for your Denk binoviewers? If so, how do you like it?

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faackanders2
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Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5591580 - 12/27/12 06:28 PM

Quote:

Anybody else buy the 1.2x 2" 45mm clear aperture OCS for your Denk binoviewers? If so, how do you like it?




Since nobody seems to be replying how they like it, I am posting "favorable" replies listed on Denkmeiers own site:



First Customer Feedback:

"I have noted that on the Catseye Nebula, that I could not see the center star before with the D21s in the Bino before the OCS-A45 and now I can see the center star with the OCS-A45!!! That is proof positive that it has expanded what you can now see and it is definitely an improvement. Great job Russ." - Victor

"HEY RUSS...CONGRATULATIONS ON A NICE NEW UPGRADE. THE NEW 45MM OCS IS TERRIFIC. I POSTED THIS ON CLOUDY NIGHTS TONIGHT! We were able to run some tests with the new Denk 45mm OCS at Chiefland tonight using two large scopes of different focal ratios...a 16" f/4.3 and my 28" f/3.66. Tomorrow night, we'll add some longer focal ratios.

FIRST - the image is noticeably brighter in both scopes than with the 'standard' OCS. This was verified both visually and photographically.

We're not talking about a BIG difference...but it is definitely noticeable.

On an extremely faint object, such as Comet 168P, using the 28" scope, the visible tail was perhaps 30% longer and the coma ahead of and around the nucleus was perhaps twice as large using the 45mm OCS vs.the 'standard'.

Understand that these differences were not immediately apparent to a casual observer but were able to be detected with diligent observation.

M-31 was obviously brighter and, in quick DSLR imaging at identical settings, with the same camera, faint details were much easier to detect. All observers agreed that the star images were much sharper and nebulosity more contrasty with the 45mm.

In the f/4.3 scope, the field of view SEEMED larger but we were not able to put a number to it. In the f/3.66 there was no doubt. Images confirmed a REAL increase of ~15%.

More testing will follow but it is readily apparent that, for 'fast' scopes, the new 45mm OCS is a definite improvement and, in my opinion, something you should seriously consider as an upgrade to your Denk BinoViewer". -Mike Harvey


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5593140 - 12/28/12 06:57 PM

S&T Feb 2013 page 60 shows new Denkmeier Binotron-27mm super system with 27mm prisms and 45mm clear aperture OCS.

Anybody know what size prisms the Denk II system has?
I am trying to figure out how the new system would differ from mine (assuming just one power switch with the 45mm clear aperture multipurpose OCS).

Ken


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Sgt
Pooh-Bah
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Reged: 12/17/05

Loc: Under the southern horn of the...
Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5593842 - 12/29/12 06:37 AM

26mm I seem to remember reading.

EDIT: I see Mr Bill thinks the same.

Edited by Sgt (12/29/12 06:39 AM)


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winterprillan
member


Reged: 04/14/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5594166 - 12/29/12 11:04 AM

I got the 45 ocs. I have compared it to the 37 ocs but i couldnīt tell any difference in sharpness, they where both equaly sharp to my eyes. I bought it because i got a 30 f3,6 on order and the bigger ocs will capture more light from the steper lightcone

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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: winterprillan]
      #5599753 - 01/01/13 02:43 PM

Quote:

I got the 45 ocs. I have compared it to the 37 ocs but i couldnīt tell any difference in sharpness, they where both equaly sharp to my eyes. I bought it because i got a 30 f3,6 on order and the bigger ocs will capture more light from the steper lightcone




You may notice a gain in brightness on very dim objects like M110 (comparing 45mm clear aperture to 38mm clear aperture 1.2x Multiplier OCS versions). I did not notice a difference on bright objects, but could see the Full Moon dust light cone projecting on the black orriface of the 38mm clear aperture OCS, so I know for sure the 45mm clear aperture is receiving more light.


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winterprillan
member


Reged: 04/14/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5601171 - 01/02/13 12:32 PM

but could see the Full Moon dust light cone projecting on the black orriface of the 38mm clear aperture OCS, so I know for sure the 45mm clear aperture is receiving more light.




Hi
was this when you used the 0,87x mode or 1,2x?
Did the 45 ocs catch all the light from the moon?


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faackanders2
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Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: winterprillan]
      #5601889 - 01/02/13 08:24 PM

Quote:

but could see the Full Moon dust light cone projecting on the black orriface of the 38mm clear aperture OCS, so I know for sure the 45mm clear aperture is receiving more light.




Hi
was this when you used the 0,87x mode or 1,2x?
Did the 45 ocs catch all the light from the moon?




Definitely lowest power 0.87x why I got the 45mm clear aperture when I already had a 38mm 1.2x multipurpose OCS.
However I am unsure whether I was using two or one extension to get the required infocus to focus. I originally was using two extensions before I realized my eyes were right at the limit of being able to use just one extension (others that view with me may not be so lucky).
Note even with one extension I need to remove my astrocrumb filter slide for the very lowest power setting (the one exception of the 3x3x2=27 power options, which I am willing to live with).


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5601909 - 01/02/13 08:36 PM

Yes, I believe the 45mm OCS caught all the full moon's dust light cone, or came very close in the lowest power switch mode.

Not really an issue for the other higher powers, which may be why Russ delayed making if for several years. After giving up waiting, and me ordering the 38mm 1.2x OCS he may have realized there is a real market for wider views (and the future need for 45mm clear aperture to make it less/non vignetted for which I reatly thank him!).


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gb_astro
sage


Reged: 01/01/08

Loc: Sydney, Australia
Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5643208 - 01/25/13 07:27 PM

The previous Denk OCS was a x2 while the new 45mm, according to it's pdf, seems to be x2.3.

How do we get to x1.2?

gb.


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johnnyha
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Reged: 11/12/06

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Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: gb_astro]
      #5643224 - 01/25/13 07:39 PM

Quote:

The previous Denk OCS was a x2 while the new 45mm, according to it's pdf, seems to be x2.3.

How do we get to x1.2?

gb.



I believe this woud be the approximate magnification when the PowerXSwitch is in reducer mode.


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: johnnyha]
      #5643554 - 01/25/13 11:15 PM

Quote:

Quote:

The previous Denk OCS was a x2 while the new 45mm, according to it's pdf, seems to be x2.3.

How do we get to x1.2?

gb.



I believe this woud be the approximate magnification when the PowerXSwitch is in reducer mode.




Unsure with the new Denk binoviewers, but with the old Denk II dual arm power switch this 2" "Multi-Purpose" OCS yields 1.2x/1.8x/2.3x in a newtonian (and with an additional reducer powerswitch the lowest power yields 0.87x in LL mode).

The 2" "Newtonian" OCS yields 1.4x/2.0x/2.5x in a newtonian (and with an additional reducer powerswitch the lowest power yields 1.0x in LL mode, and 3.3x in HH mode).

The 2" "Multipler" OCS yields 1.8x/2.6x/3.2x in a newtonian (and with an additional reducer powerswitch the lowest power yields ?.?x in LL mode).

Ken


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5643571 - 01/25/13 11:29 PM

Quote:


Unsure with the new Denk binoviewers, but with the old Denk II dual arm power switch this 2" "Multi-Purpose" OCS yields 1.2x/1.8x/2.3x in a newtonian (and with an additional reducer powerswitch the lowest power yields 0.87x in LL mode).

Ken




I bought the original 38mm clear aperture 2" "Multi-purpose" OCS before the 45mm clear aperture version was available, and may have ben the first to buy the new one. I can visually confirm both are the same power and AFOV/TFOV, and the only diference is the clear aperture (preventing vignetting of the light cone entering the OCS in lowest power mode with inward spacer(s) required to focus.

The Multipurpose view is so much wider than than the Newtonian (similar to the difference betwee the Newtonian and the Multiplier), but still can't fit M45 nor M33 in my 1.5 f4.1 Dob. But then I can fit these in with my 2" 40mm 70 AFOV single eyepiece either (1.5 deg TFOV).


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gb_astro
sage


Reged: 01/01/08

Loc: Sydney, Australia
Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5643766 - 01/26/13 03:42 AM

As long as we don't confuse it with inherent low power OCSs like Siebert offer.

gb.

Edited by gb_astro (01/26/13 03:50 AM)


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johnnyha
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Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: gb_astro]
      #5643793 - 01/26/13 04:31 AM

Isn't Siebert's similar, an OCS in front of a reducer...

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gb_astro
sage


Reged: 01/01/08

Loc: Sydney, Australia
Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: johnnyha]
      #5643907 - 01/26/13 07:57 AM

Quote:

Isn't Siebert's similar, an OCS in front of a reducer... ng.




Maybe, but the point is that to get x1.2 from the Denk OCS you have to have a Power Switch.
Not everyone has or wants the Denk Power Switch but they might be very interested in a
45mm clear aperture OCS on it's own, especially if it was x1.2 as this thread's tile implies.

gb.


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johnnyha
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Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: gb_astro]
      #5643998 - 01/26/13 09:11 AM

I was under the impression that the Siebert low mag 1.25X newt OCA does have a second element or "reducer" before the OCA, incorporated into the setup. At least that's what I see in the diagrams. It's not possible to have a 1.2X OCS that works "on it's own" in a fast newt without serious vignetting.

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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: gb_astro]
      #5644088 - 01/26/13 10:12 AM

Quote:

Quote:

Isn't Siebert's similar, an OCS in front of a reducer... ng.




Maybe, but the point is that to get x1.2 from the Denk OCS you have to have a Power Switch.
Not everyone has or wants the Denk Power Switch but they might be very interested in a
45mm clear aperture OCS on it's own, especially if it was x1.2 as this thread's tile implies.

gb.




I started this thread and gave the title, because 1.2x is what Russ referred it as, since it is easier to say one number than three, and the lowest power is what decides if it will work with your telecope's infocus limits (or if internal spacers will be required to focus). Russ also initally advertised the 2" OCS for Newtonians, hence the title even though the actual OCS I am referring to has "Multi-Purpose" written on if to distinguish it from the others. If you have any questions for use with other telescopes besides Newtonian, please ask Russ at Denkmeier.

There is never a problem barlowing or going to a higher power since this just needs out focus and possibly outward extensions for the really high powers.


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faackanders2
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Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5644449 - 01/26/13 01:55 PM

This is what Russ Lederman posted on the Vender Forum (See he even refers it as the 1.2x):

"At WSP, quite a few years ago, Mike Zammit of Star Structure along with Steve Kennedy, a fine fast mirror maker in California and user of our Denk II Binos with both 1.4X and 1.2X OCS* had let me know that the super fast scopes they were using had been shown through ray tracing to have some noticable fall off of illumination with the lower power 1.2X optical lens. Not real bad, but observable.

Basically, to transfer the image plane through the light path of the Denks (this would hold true with any binoviewer), the optical lens must be located rather deeply into the focal plane of the scope, often entering the upper cage a bit. Here's where it gets a bit tricky when deciding whether to use the 1.2X or the 1.4X lenses. The 1.2X requires .75" deeper location than the 1.4X. however, most of you who set out to have a very large and fast dob not only want a short "stepstool-ready" scope, but you want a wide true field of view (TFOV) too. Mike Z. did some on site ray tracing at WSP and determined that going with the 1.4X would be a better option due to the very steep cone in what was an F3.75 mirror, if I remember correctly. remember that it needs to go into the focal plane .75" LESS.

The clear aperture of both the 1.2X and 1.4X OCS lenses were and still are 37mm. The new optic as mentioned is 45mm clear aperture and has the same lower power 1.2X factor.

I was asked if I could make a low power 1.2X with as much clear aperture as possible to negate this clipping. I felt that in a sense, it was not a good option to make 100 optics, especially if the typical blanks that we were already using were 40mm and new tooling, New Cells, retainers, raw material etc. would be required in large numbers. For how many fast dobs? 10? Yikes!

So I sort of declined and had been telling customers with fast dobs that opting for the 37mm 1.2X or 1.4X was a decision they would have to make, weighing the tradeoffs between low power and some falloff/clipping, or less of it with the higher power 1.4X lens.

Well, things being what they are, I am a huge dob fan. I use my own 20" F/f5 with a John Hall mirror (Pegasus) for many years now. But I felt it was finally time to go ahead with this optic since more and more super fast mirrors are showing up and Steve Kennedy felt this would be a very good thing.

My opinion is that ANY dob F/5 or faster should choose this upgrade. F/5 is fast in the telescope world. Typically, large Dobs are expensive and well worth it! So, why not have the largest OCS optic possible in a 2" focuser doing the work? I need a good night to really cross test the 37mm vs the 45mm in my own F/5 but I can say I'd use the 45mm in any case to be sure there is an easily observable gain. I used the 1.2X 37mm in my scope and always had. Now of course, I will use the 45mm! It's here if people want it. Its an honest effort to make an OCS with largest possible clear aperture for a 2" focuser available for those who want one. If I'm trying to grab some photons, I want as many as possible.

*OCS=Optical Corrector System, a term that has been sort of hijacked and used by some others with slight changes. Note that the values of 1.2X and 1.4X are derived via the introduction of the low power optic in the Denk Bino's power switch, used in combination with the large OCS optic. Used alone, these OCS cells would render appx. 2.3X (lower power)vs 2.5X (higher power)in the Denk Binoviewers.
-Russ"

I did not edit Russ' above comments, and I have no affiliation with Denkmeier, except being a very satified customer with DenkII, dual powerswith, additional reducer/multiplier power switch, four 2" OCSs, and one 1.25" OCS. I wish Russ long term sucess of his company, and thank him for making the 45mm clear aperture OCS a possibility (which I have been asking him about for several years before I bought the 1.2x OCS).

Ken


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gb_astro
sage


Reged: 01/01/08

Loc: Sydney, Australia
Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5644931 - 01/26/13 07:09 PM

"This is what Russ Lederman posted on the Vender Forum (See he even refers it as the 1.2x):"

Yes, but he finally clarifies it in the footnote.
Perhaps it is just his marketing instinct to promote it's lowest possible magnification (in his system)
since that is usually the holy grail of binoviewing.

gb.

Edited by gb_astro (01/26/13 07:12 PM)


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: gb_astro]
      #5645087 - 01/26/13 08:33 PM

Quote:

"This is what Russ Lederman posted on the Vender Forum (See he even refers it as the 1.2x):"

Yes, but he finally clarifies it in the footnote.
Perhaps it is just his marketing instinct to promote it's lowest possible magnification (in his system)
since that is usually the holy grail of binoviewing.

gb.




And with an additional reduer switch this can be brought down to 0/87x? The decision which one you are able to use is based on infocus ability of your scope at lowest power. Hence the low power side is the critical deciding factor; hence I don't see any issue with how he refers it to Newtonian uses with dual power switch. I did not buy the 1.2x OCSs for any other reason than its' lowest power ability (accepting vignetting at 37mm clear aperture), and then upgrading same 1.2x with 45mm clear aperture. You DO NOT need 45mm clear aperture for the higher powers, since those don't vignette due to infocus. There is no deception, and he used to list all the powers with the old Denk II when you selected your 2" OCS (for your Newtonian).

For SCTs and Refractors everything is different, please contact Russ or refer to denk site.


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faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: New Denk Newtonian 1.2x 2" 45mm clear aperture OCS new [Re: faackanders2]
      #5672340 - 02/10/13 01:09 PM

Last night I decided to compare the 1.2x2"45mm Multipurpose OCS (with 1 extension) to the 1.4x2" 38mm Newtonian OCS (no extension) with the views of M45, Jupiter, M42/M43 [and NGC1981(HT30), Col72(HT31); could NOT see NGC1977(HT32), NGC1999(HT33) nor NGC2024(HT34)]. I used my Denk II with dual 3x3 power switch on my 17.5" f4.1 Dob and 24mm 68 AFOV Panoptic eyepieces and astrocrumb/denk filter switch from my driveway. At the end there was slight ice dew on my scope tube and chair, but neither ice/dew efffected the viewes of my eyepiece nor telrad.

M45 Pleadies: Actually last object observered.
*1.2x(really 0.87x in LL powerswith mode) - able to see most of the dipper and easily recognized as M45, but not able to fit all of M45 in same FOV. Required panning.
*1.4x(really 1.0x in LL powerswith mode) - able to see some of the dipper and less recognizabled as M45, beeing able to fit lesl of M45 in same FOV. Required more panning.
* Did not use any of the other higher powerswith modes for M45.

Jupiter and 4 moons:
*1.2x/1.8x/2.3x(really 0.87x in LL, 1.2x in LM, x? in ML, ?x in HL, 1.8x in MM, and ?x in HM powerswith mode) - able to see jupiter 2-3 dark bands and dark polar caps with skyglow filter, and 4 moons cosisting of three in a slightly elongated isocoles triangle pointing to the outer moon. Unfiltered provided natural colors but with less band/pole detail. Ultrablock and OIII too dark and less band detail.
*1.4x/2.0x/2.5x(really 1.0x in LL, 1.4x? in LM, 1.43x?x in ML, 1.79x? in HL, 2.0x in MM, and 2.5x? in HM powerswith mode) - Overall larger and better view of Jupiter with 3 dark bands and dark polar caps with skyglow filter, and 4 moons cosisting of three in a slightly elongated isocoles triangle pointing to the outer moon. Unfiltered provided natural colors but with less band/pole detail. Ultrablock and OIII too dark and less band detail.
*Did not use LH, MH, nor HH power swith modes for either OCS.
*Did not use 1.8x/2.6x/3.2x Multiplier OCS which would have provided best higher powers of Jupiter based on past viewing experiences.

M42/M43 Orion Nebula:
*1.2x/1.8x/2.3x(really 0.87x in LL, 1.2x in LM, x? in ML, ?x in HL, 1.8x in MM, and ?x in HM powerswith mode) - 4 star trapezium visible in all powers, M42 visible unfilered but skyglow, ultrablock, and OIII bring out M43 head, and M42 awings and notch in diamond body, with losing stars. OIII especially brightened body. LL with extension only setting not able to use astrocrumb(denk version) filter switch. All other power switch modes enabled use of filters which were preferred views. All view up to MM mode did not crop the wings and higher power provided greater detail without increasing fuzziness.
*1.4x/2.0x/2.5x(really 1.0x in LL, 1.4x? in LM, 1.43x?x in ML, 1.79x? in HL, 2.0x in MM, and 2.5x? in HM powerswith mode) - 4 star trapezium visible in all powers, M42 visible unfilered but skyglow, ultrablock, and OIII bring out M43 head, and M42 awings and notch in diamond body, with losing stars. OIII especially brightened body. LL without extension able to use astrocrumb(denk version) filter switch and hence this is the preferred OCS for this size nebulae in my 17.5" dob, since all views up to MM mode did not crop the wings and higher power provided greater detail without increasing fuzziness.
*Did not use LH, MH, nor HH power swith modes for either OCS.

Ken


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