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New Denk Newtonian 1.2x 2" 45mm clear aperture OCS

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#1 faackanders2

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Posted 02 September 2012 - 10:32 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.

#2 john smith

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Posted 02 September 2012 - 10:43 AM

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

#3 faackanders2

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Posted 22 September 2012 - 10:23 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!

#4 faackanders2

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Posted 23 September 2012 - 07:02 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.

#5 faackanders2

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Posted 09 October 2012 - 08:51 PM

Anyone else take the plunge?

#6 faackanders2

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Posted 14 October 2012 - 02:05 PM

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

#7 Mr. Bill

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Posted 23 October 2012 - 02:56 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.

:question:

#8 johnnyha

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Posted 23 October 2012 - 04:03 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.

#9 faackanders2

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Posted 31 October 2012 - 11:26 PM

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.

#10 faackanders2

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Posted 15 December 2012 - 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?

#11 faackanders2

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Posted 27 December 2012 - 06:28 PM

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

#12 faackanders2

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Posted 28 December 2012 - 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

#13 Sgt

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Posted 29 December 2012 - 06:37 AM

26mm I seem to remember reading.

EDIT: I see Mr Bill thinks the same.

#14 winterprillan

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Posted 29 December 2012 - 11:04 AM

I got the 45 ocs. I have compared it to the 37 ocs but i couldnĀ“t 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

#15 faackanders2

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Posted 01 January 2013 - 02:43 PM

I got the 45 ocs. I have compared it to the 37 ocs but i couldnĀ“t 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.

#16 winterprillan

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Posted 02 January 2013 - 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. [/quote]

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

#17 faackanders2

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Posted 02 January 2013 - 08:24 PM

[quote name="winterprillan"]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. [/quote]

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

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).

#18 faackanders2

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Posted 02 January 2013 - 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!). :bow:

#19 gb_astro

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Posted 25 January 2013 - 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.

#20 johnnyha

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Posted 25 January 2013 - 07:39 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.

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

#21 faackanders2

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Posted 25 January 2013 - 11:15 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.

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

#22 faackanders2

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Posted 25 January 2013 - 11:29 PM

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).

#23 gb_astro

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Posted 26 January 2013 - 03:42 AM

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

gb.

#24 johnnyha

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Posted 26 January 2013 - 04:31 AM

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

#25 gb_astro

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Posted 26 January 2013 - 07:57 AM

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