10 replies to this topic

[The Ardent]

Just arrived today. 

This is a second Binovue I bought for the dob. The original eyepiece holders were sticking so I decided to try the Siebert diopters. I don't think I'm alone in wanting Televue to add a diopter. 

 

The OCA is the 1.3x 38mm model. I didn't get the multi-mag OCA as the TV 2x amplifier works great for planetary. 

 

Now ow I need some decent weather. 

 

 

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[junomike]

How hard/easy was the diopter Swap?  

Is the 1.3x OCS available or did you have it made.

 

Mike

[The Ardent]

The TV 2x amplifier and the Siebert have the same threads. Easy to switch. (Note I haven't actually used it yet)

Diopter:
From our phone conversation, it's an easy fix. I send the BV to him and he does all the work. I think most of his stuff is made one at a time.
Real nice to work with, but he has a backlog of projects.

[junomike]

Ah ok. I looked up the ocs.... interesting.  

A tad pricey IMO, but if it works then it's worth it. 

 

Mike

[The Ardent]

i only wish the Binotron with 45 OCA worked with my f/3.5 dob. It produced a focused image at all 3 powers (nice) but the stars had aberrations that increased with magnification. When I tried it if/5 dobs, I didn't see any problems.

So the Siebert OCA is my last effort at low power binoviewing with the dob. It's hard to beat low power mono with an Ethos. We'll see.

[scarubia]

i only wish the Binotron with 45 OCA worked with my f/3.5 dob. It produced a focused image at all 3 powers (nice) but the stars had aberrations that increased with magnification. When I tried it if/5 dobs, I didn't see any problems.

So the Siebert OCA is my last effort at low power binoviewing with the dob. It's hard to beat low power mono with an Ethos. We'll see.

 

Ray, Seibert claims the 38mm OCA is designed to work well down to f2.9. Let us know how it works out for you.

 

Sebastian

Edited by scarubia, 22 June 2015 - 07:35 PM.

[Catapoman]

Just arrived today. 

This is a second Binovue I bought for the dob. The original eyepiece holders were sticking so I decided to try the Siebert diopters. I don't think I'm alone in wanting Televue to add a diopter. 

 

The OCA is the 1.3x 38mm model. I didn't get the multi-mag OCA as the TV 2x amplifier works great for planetary. 

 

Now ow I need some decent weather. 

 

Nice job from Harry!  Hope you get a chance soon to use them.

[The Ardent]

Finally a week later we had clear skies. Temps were below 80F and humidity briefly below 50%. The seeing was poor for the first two hours after sunset. The bright moon didn't help. 

I took the dob out  around twilight. Trees obscured the moon and planets. My only observing window is northeast to east. 

Collimated with Glatter laser and Tublug. Verified with older version  Catseye Cheshire and autocollimator (new tools on order) 

Installed viewing assembly: Siebert OCS, TV Binovue with Siebert diopters, pair 30mm Ultimas. 

First target was Vega. Able to focus (whew! - how many times I've tried a binoviewer scope combo and it didn't focus) The left and right didn't focus together. A little fiddling took care of that. No sign of miscollimated eyepieces. I did have problems from the exit pupil (my astigmatism) a little vignetting, and a little coma at the edge. The OCS is not used with the Paracorr. 

Next I tried 24 Pans. Much better presentation from the wider apparent field and reduced astigmatism. 16  and 11 Naglere followed. Targets included Beta Lyr, T Lyr, M57, M13, Albireo, Blinking Planetary, IC 4996, and the rich background of the Cygnus Milky Way. I'm pretty sure I saw Chi Cygni also. 

On  M13 I compared the 16 T5's versus 13E + Paracorr. The Ethos provided a wide field and slightly brighter view. The BV view was a little dimmer, but not objectionable. There was no loss of details, no aberrations, the stars were round except at the edge where coma took over. 

The moon transited a gap in the trees so I had about 10 blinding minutes of moon. Despite the poor seeing the moon reveals a wealth of detail. For example a triple point of light: the top of the central peak in Vieta, and the morning sun on either side of the peak's shadow. Saturn was too low to be visible. 

I'm very pleased with the Siebert OCS after last night. I want to test it under dark skies and better conditions.  I wish it accepted 2" filters. There's a big difference in using the TV 2x amplifier and the 1.3x OCS. It's nice to have both options available. 

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[scarubia]

Finally a week later we had clear skies. Temps were below 80F and humidity briefly below 50%. The seeing was poor for the first two hours after sunset. The bright moon didn't help. 

I took the dob out  around twilight. Trees obscured the moon and planets. My only observing window is northeast to east. 

Collimated with Glatter laser and Tublug. Verified with older version  Catseye Cheshire and autocollimator (new tools on order) 

Installed viewing assembly: Siebert OCS, TV Binovue with Siebert diopters, pair 30mm Ultimas. 

First target was Vega. Able to focus (whew! - how many times I've tried a binoviewer scope combo and it didn't focus) The left and right didn't focus together. A little fiddling took care of that. No sign of miscollimated eyepieces. I did have problems from the exit pupil (my astigmatism) a little vignetting, and a little coma at the edge. The OCS is not used with the Paracorr. 

Next I tried 24 Pans. Much better presentation from the wider apparent field and reduced astigmatism. 16  and 11 Naglere followed. Targets included Beta Lyr, T Lyr, M57, M13, Albireo, Blinking Planetary, IC 4996, and the rich background of the Cygnus Milky Way. I'm pretty sure I saw Chi Cygni also. 

On  M13 I compared the 16 T5's versus 13E + Paracorr. The Ethos provided a wide field and slightly brighter view. The BV view was a little dimmer, but not objectionable. There was no loss of details, no aberrations, the stars were round except at the edge where coma took over. 

The moon transited a gap in the trees so I had about 10 blinding minutes of moon. Despite the poor seeing the moon reveals a wealth of detail. For example a triple point of light: the top of the central peak in Vieta, and the morning sun on either side of the peak's shadow. Saturn was too low to be visible. 

I'm very pleased with the Siebert OCS after last night. I want to test it under dark skies and better conditions.  I wish it accepted 2" filters. There's a big difference in using the TV 2x amplifier and the 1.3x OCS. It's nice to have both options available. 

 

Ray glad to hear you found a solution to your problem. FYI, Siebert does sell a 2" filter attachment that screws into the OCS for your filters. 

[The Ardent]

I wanted the 2" filter for the moon! Look away from the eyepieces and half my vision is gone. 

 

Im still ruminating over my session last night. Some thoughts

 

Using two eyes is so relaxing and natural (that's why we're in this subforum) 

Reduction of FOV and minimal magnitude loss is a small price to pay for luxurious viewing. Comparing M13 in mono/Bono mode, the same stars were visible in the cluster. I studied the periphery stars too.  The brightest stars along the Propeller that have an orange tint in mono, the color is washed out in bino. It's wasn't until this year that I even saw color in a globular. 

I can't use the Astrocrumb filter slide with the bino. 

Will I abandon monoviewing? Wayyyy to early to even think about that. 

Harry mentions on his website the superiority of the Televue 2x amplifier, and its limitations. My next question, how does my setup compare to a Baader Mark V with GPC? Eventually I'm going to upgrade. Baader or Echelon? Both are intriguing options for a distant time and place.  I just have too much going on right now. 

[faackanders2]

I wanted the 2" filter for the moon! Look away from the eyepieces and half my vision is gone. 

 

Im still ruminating over my session last night. Some thoughts

 

Using two eyes is so relaxing and natural (that's why we're in this subforum) 

Reduction of FOV and minimal magnitude loss is a small price to pay for luxurious viewing. Comparing M13 in mono/Bono mode, the same stars were visible in the cluster. I studied the periphery stars too.  The brightest stars along the Propeller that have an orange tint in mono, the color is washed out in bino. It's wasn't until this year that I even saw color in a globular. 

I can't use the Astrocrumb filter slide with the bino. 

Will I abandon monoviewing? Wayyyy to early to even think about that. 

Harry mentions on his website the superiority of the Televue 2x amplifier, and its limitations. My next question, how does my setup compare to a Baader Mark V with GPC? Eventually I'm going to upgrade. Baader or Echelon? Both are intriguing options for a distant time and place.  I just have too much going on right now. 

"Can't use astrocrumb filter slide with binos."

 

If you have a Dob I assume this means spider arms/vanes are directly above focuser.

 

If not, you could use one with the denkmeier adapter which allows about 2" of infocus, so the filters are 2" inward in the dob tube.  That is my configuration, and I can use the astrocrumb filter slide with both binoviewers and single eyepieces (1.25" & 2").