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Equipment Discussions >> Binoviewers

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johnnyha
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Interesting Mark V/Powermate Configurations
      #5185669 - 04/23/12 12:57 AM Attachment (121 downloads)

It's a foggynight here in Los Angeles, and I've been experimenting with my T-2 system with the Mark V binoviewers. Has anyone tried this particular configuration? That's a 2x Powermate with the body removed and a T-ring Adapter in place. I then screwed the Powermate T-ring directly into the Baader T-2 prism diagonal in place of the nosepiece.

(The three silicon o-rings on the barrel are spacers I use since the Powermate has an extra-long barrel that tends to bottom out in diagonals.)


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johnnyha
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Re: Interesting Mark V/Powermate Configuration! new [Re: johnnyha]
      #5185680 - 04/23/12 01:08 AM Attachment (91 downloads)

I haven't had a chance to try this configuration yet but I have had excellent results in the past using the Powermate/T-ring combo attached directly to the Mark V binos and placed into a 2" diagonal. I can achieve powers of 2X and also 2.5X and 3.4X with my two glasspath correctors. Best part is I have never need to add any extensions when using the binoviewer in the TEC140 with the Powermate, even with my 1.7X Glasspath and the Powermate giving me 3.4X+. However that is when using the Powermate in a 2" mirror diagonal, not directly ahead of the T-2 prism diagonal as a nosepiece.

[UPDATE: Hrm. Played with this awhile and the T-ring adapter nosepiece connection can unscrew pretty easily - CLUNK! To use this combo safely you would have to be very careful to keep the binoviewers rotated to the right side of the OTA (one or two o'clock position) so their weight will tighten the connection to the diagonal]. Can't wait to try it out when the weather clears up. Or not, maybe this is just too dangerous, I don't want my diagonal rotating on me!

BTW the Powermate works *extremely* well with the Mark V binoviewers, I have found the telecentric lens is better than a barlow at delivering crisp star images at high magnifications. It's also a great way to use Mark V binoviewers in refractors without the focus position changing much.


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johnnyha
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Re: Interesting Mark V/Powermate Configuration! new [Re: johnnyha]
      #5185753 - 04/23/12 02:16 AM Attachment (101 downloads)

This is how I normally use the Mark V/Powermate combo, I've posted this before. I place this combo in a 2" diagonal for my refractors and it comes to focus very close to my eyepieces so it doesn't require a lot of in or out focus. However the configuration pictured in the first two posts is much lighter and has at least an inch+ shorter light path.

In newt mode I place the combo directly in my 15" dob focuser - there is no extra spacer or extension required and no clipping!


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johnnyha
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Re: Interesting Mark V/Powermate Configuration! new [Re: johnnyha]
      #5188607 - 04/24/12 06:20 PM Attachment (85 downloads)

OK here's a really nice setup with the Mark Vs and 2X Powermate/T-ring combo. I got this new model Baader Clicklock from Agena Astro and removed the 1.25" nosepiece - it already has the $28 T-2 expansion adapter inside. I was able to screw the 2" Clicklock directly into the T-2 diagonal. This is an extremely secure setup and should not require much backfocus. I had been putting the Mark V/Powermate combo in a 2" mirror diagonal before, but this is much more optimal.

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Paul C-I
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Re: Interesting Mark V/Powermate Configuration! new [Re: johnnyha]
      #5195118 - 04/28/12 03:00 PM

I've also used this configuration on an intes mn68. Superb image and comes to focus. Hoping this will be the same story in my newly arrived MN78 scope. I thought it gave a better image than the Baader newt 2" compensator.
YMMV

Paul


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johnnyha
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Re: Interesting Mark V/Powermate Configuration! new [Re: Paul C-I]
      #5195127 - 04/28/12 03:05 PM

The bottom lip of the 2" eyepiece holder does overlap the front of the diagonal body a little, I could not get the nosepiece all the way into my TEC140 compression back. However when I put a T-ring changer on the Clicklock holder, it lifted it up from the diagonal body enough to where I had no problem. This configuration has almost TOO much backfocus, at 3.4X with the 1.7X glasspath installed, the TEC 140 drawtube was only racked out 1". I'll check later to see how it works at 2.5X (2X Powermate with 1.25X glasspath), and at 2X with no glasspath. I may need to switch back to using a 2" mirror diagonal to achieve focus!

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DaveJ
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Re: Interesting Mark V/Powermate Configurations new [Re: johnnyha]
      #5477459 - 10/18/12 05:42 PM

Quote:

It's a foggynight here in Los Angeles, and I've been experimenting with my T-2 system with the Mark V binoviewers. Has anyone tried this particular configuration? That's a 2x Powermate with the body removed and a T-ring Adapter in place. I then screwed the Powermate T-ring directly into the Baader T-2 prism diagonal in place of the nosepiece.

(The three silicon o-rings on the barrel are spacers I use since the Powermate has an extra-long barrel that tends to bottom out in diagonals.)




Johnny,

Any idea how much more the 2x magnification factor is when the 2x Powermate is located in front of the diagonal (photo 1&2 in this thread) than when it's mounted to the binoviewer (photo 3)? For example, say you were using a 1.7 GPC in each instance - what would the net magnification be in each setup?


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johnnyha
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Re: Interesting Mark V/Powermate Configurations new [Re: DaveJ]
      #5477496 - 10/18/12 06:08 PM

Unlike a traditional barlow, I believe the Powermate is supposed to maintain the same magnification factor regardless of the distance from the eyepiece Dave, due to the telecentricity and the parellel light cone. This was more an exercise in theory, I don't use the nosepiece configuration because it needs the focuser to be racked wayyyy out, which even with my 4.5" drawtube would require adding an extension tube. The image train is already lengthened by adding the Powermate to the nose, an extension makes it worse. I still often use the Powermate/T-ring adapter in the diagonal as photo 3, it gives me the cleanest possible high magnification image. With a 1.7X glasspath I estimated around 3.2X.

I have since gotten a 2.6X glasspath and it works great on its own. You need a pretty long drawtube for that as well, but I can come to focus with 1/2" to spare now that I have the Feathertouch 3545.


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DaveJ
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Re: Interesting Mark V/Powermate Configurations new [Re: johnnyha]
      #5480041 - 10/20/12 08:47 AM

Quote:

Unlike a traditional barlow, I believe the Powermate is supposed to maintain the same magnification factor regardless of the distance from the eyepiece Dave, due to the telecentricity and the parellel light cone.




Johnny,

Would a 2" 4X Powermate (w/matching T-ring adapter) be able to be substituted for the 2X in the configurations you've shown? I imagine it would. Focus distance is the unknown here. I'm looking for higher magnification with longer focal length eyepieces.


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johnnyha
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Re: Interesting Mark V/Powermate Configurations new [Re: DaveJ]
      #5480664 - 10/20/12 04:25 PM

Yes I believe it should work fine Dave, I have never tried it. It's longer than the 2X although with the T-ring adapter I assume it would be a lot shorter than without. It may require a bit more outfocus, I am not sure. Another solution is to get the AP Barcon and screw the barlow element onto the front of the diagonal nose, and use a 1.25X gpc for 3X power or a 1.7X for around 4X? This will definitely require more outfocus than a 4X Powermate though.

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DaveJ
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Re: Interesting Mark V/Powermate Configurations new [Re: johnnyha]
      #5480704 - 10/20/12 05:09 PM

Quote:

Yes I believe it should work fine Dave, I have never tried it. It's longer than the 2X although with the T-ring adapter I assume it would be a lot shorter than without. It may require a bit more outfocus, I am not sure. Another solution is to get the AP Barcon and screw the barlow element onto the front of the diagonal nose, and use a 1.25X gpc for 3X power or a 1.7X for around 4X? This will definitely require more outfocus than a 4X Powermate though.




I swear. It seems that half the fun of owning these things is the building of all the possible configurations! With the 4X Powermate (fortunately, they're on sale at the moment) + T-Ring adapter, I'd be able to achieve 300+ magnification with the TEC 140 using 13mm Nagler T6s or my Faworski 10.5mm orthos - both with excellent eye relief. This is withOUT using any GPC. I don't know if it's wise using no GPC, but with the narrow light cone coming from the 4X Powermate, I think I'd be good to go. Heck, in that configuration, the 16mm Nagler T5s would give 245X and the Faworski 16.8mm would give 233X. All very acceptable values. Adding the 1.25 GPC (if required for the Mark Vs) would yield 292X with the Faworski 16.8mm orthos and I love those eyepieces. Going to the 1.7 GPC would yield 278X with the Brandon 24s. As the McDonald's commercial says, "I'm lovin' it!" Using the 2X Powermate with the 2.6 GPC yields wonderful magnifications as well with 19 Pans, 16.8 Faworski and 16 Naglers. This is so much fun on a cloudy rainy afternoon.


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DaveJ
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Re: Interesting Mark V/Powermate Configurations new [Re: johnnyha]
      #5480709 - 10/20/12 05:13 PM

Quote:

Yes I believe it should work fine Dave, I have never tried it. It's longer than the 2X although with the T-ring adapter I assume it would be a lot shorter than without. It may require a bit more outfocus, I am not sure. Another solution is to get the AP Barcon and screw the barlow element onto the front of the diagonal nose, and use a 1.25X gpc for 3X power or a 1.7X for around 4X? This will definitely require more outfocus than a 4X Powermate though.




Something I left out of my first reply is that I haven't been able to find an A-P Barcon, unfortunately. I'm going to call A-P this coming week and see if they can tell me when the new Barcon will be available. Anybody here have one they're willing to let go?


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johnnyha
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Re: Interesting Mark V/Powermate Configurations new [Re: DaveJ]
      #5480757 - 10/20/12 05:56 PM

Welp, I bought the Barcon that was on the other site two days ago. I had one once, before I had my MkVs and stupidly sold it, so i am looking forward to trying it again with my current setup.

I found that powers over 250X in the TEC140 were too dim for my taste when binoviewing, YMMV. Of course if you view double stars that is a different matter. But for planetary I think going up to say 3X with the Barcon element and 1.25X would be fine, you could still achieve 250X with a 12mm or put in the 1.7 gpc + Barcon for around 4000 fl and get 250X with 16mm. The 4X Powermate just seems like overkill to me especially if you have the 2X Powermate and a 1.7X gpc which gets around 3.2X. Yep it's all fun!


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Stellarfire
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Re: Interesting Mark V/Powermate Configurations new [Re: johnnyha]
      #5669026 - 02/08/13 01:22 PM

Just found this interesting thread.

Johnny, I have a question to the compact setup as pictured in your OP, which shows the following optical train:

2x Powermate 2" (body removed)-> Powermate T-ring Adapter-> Baader T-2 Diagonal-> Quick Changer-> Baader Mark V

Using your FS-152, did you try if this setup comes to focus without any GPC in the Mark V bino, and if yes, how much focuser inward travel remains until fully racked-in position?

Stephan


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ewave
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Re: Interesting Mark V/Powermate Configurations new [Re: Stellarfire]
      #5669383 - 02/08/13 04:39 PM

Yes, I saw you mention this in another post. I am getting the Baader Maxbrights, with t2 diagonal and hope to try a 2x PM. I hope to try this combo with my sct and a pair of newly aquired 18mm baader orthos since I like eps with larger eye relief when binoviewing and easier to merge images. Thanks for this advice, especially since their is no 2x GP.

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johnnyha
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Re: Interesting Mark V/Powermate Configurations new [Re: ewave]
      #5669744 - 02/08/13 08:46 PM

Quote:

Using your FS-152, did you try if this setup comes to focus without any GPC in the Mark V bino, and if yes, how much focuser inward travel remains until fully racked-in position?




Stephan - yes it comes to focus with just the Powermate, no problem. I'll need to double check on the T2/2" Clicklock configuration, I don't really use that, I use the Mark V/2X Powermate in a regular 2" diagonal. There are no backfocus issues with the 2" setup, I believe the focal position is midway using a 2" diagonal, about the same as a regular eyepiece...


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Stellarfire
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Re: Interesting Mark V/Powermate Configurations new [Re: johnnyha]
      #5670076 - 02/09/13 02:31 AM

Johnny,

Thanks very much for checking it! Since we have very similar refractor telescopes, it should work in my 6" APO / Mark V combo too.

According TV's Powermate Magnification Chart and considering the optical path length including Mark V bino, a magnification factor of about 2.2x or 2.3x may be expected for that setup as pictured in your OP.
So the 2x Powermate 2" will make a fine addition to Baader's 1.8x GPC 2", and A-P's BARCON, allowing fine adjustments in the resulting magnification factor.

For detailed magnification factor figures of the Baader 1.8x GPC 2" and the A-P BARCON, see also this other thread where "Dr. Homma" (Tammy) kindly provided us with some exact measurements.
(For factors of 4x and above, Baader's terrific Fluorite Flat Field Converter (FFC) is the best solution available on the market today).

I think I will have to open my purse again and will order that 2x Powermate including T-ring adapter...

Stephan


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