34 replies to this topic

[Tamiji Homma]

I have Baader FFC inside Astro-Physics extension tube.

 

 

Baader FFC inside:

 

Whole setup:

 

Tammy

[MarMax]

I’ve been thinking about the AP BARADV, but I don’t know if it will have any advantages over the Powermate.

The BARADV is a very nice Barlow but it's a Barlow. The magnification changes based on backfocus and at the really long backfocus you'll have with the CZAS it will be in the 2.7x+ range. As Denis recommends, the Powermates are a better option.

 

I have Baader FFC inside Astro-Physics extension tube.

 

 

trim

I use the same AP adapter and a 2x Powermate with the 160mm. I don't have a picture but with the 2x Powermate I don't need to use the 85mm removable focuser extension. The 160mm is custom length (binoviewer friendly) with the extension making it standard length. The 2x Powermate is nice because the magnification is very close to 2x regardless of spacing. The ADC also needs to operate in the f/12 to f/20 range to be most effective and with the 2X Powermate the scope is very close to f/14.

[vicuna]

ok finally bought some powermates to try.

 

I tried it the way some of you do in my refractor with a 2x and 2.5x powermate (with rings) in the front of my diagonal. no luck. I think it threw the focus too far back.

 

when I did it the way Denis said to (one in each eyepiece), it works.

 

am I doing anything wrong? would prefer to not use two for just ergonomic reasons for a shorter stack

 

(although tbh time-wise it's probably actually easier to stick in two powermates than take out my diagonal and screw out a nosepiece and screw in a powermate)

 

thank you!

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Edited by vicuna, 13 June 2025 - 06:21 PM.

[vicuna]

this is the version that worked (allowed me to focus)

 

 

 

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[betacygni]

I have a similar issue with many of my scopes and the binotron/powerswitch, focus point goes too far out. Simple solution is a quality 2” extension tube between the focuser and diagonal of the appropriate length you need. I’m particular to the Takahashi or Televue extension tubes, much better quality than most, and you don’t want to save money on something holding your binoviewers to the scope.

Edited by betacygni, 13 June 2025 - 09:19 PM.

[vicuna]

ok I have a televue 2" extension. i'll give that a shot tomorrow with the 2x Powermate.

 

I was hoping the 2x would work for me because it's beefier (and easier to divide by 2 and 4 lol).

 

I thought powermates were not supposed to throw the focus out farther though. when i put it between the diagonal and eyepiece it doesn't change the focus.

[betacygni]

ok I have a televue 2" extension. i'll give that a shot tomorrow with the 2x Powermate.

I was hoping the 2x would work for me because it's beefier (and easier to divide by 2 and 4 lol).

I thought powermates were not supposed to throw the focus out farther though. when i put it between the diagonal and eyepiece it doesn't change the focus.

The 2.5x and 2x powermate will actually both give you about 2x ahead of the binoviewers. See the Televue powermate magnification chart: https://www.televue....?id=53&Tab=_app

Edited by betacygni, 13 June 2025 - 09:53 PM.

[vicuna]

between clouds and life and just wanting to observe and not test, I haven't gotten around to it.

 

I carved out last night to sort this out no matter what.

 

my setup is a natively friendly 140mm refractor and Denis' czas APO binoviewer.

 

with no magnification I go binoviewer with a dovetail and quick connect onto a baader T2 diagonal that has a 2" nosepiece right into my telescope.

 

I tried an AP Barlow, Televue 2x, and Televue 2.25x. I had adapters to screw right into the diagonal. also had some extenders on hand. I tried every configuration between screwing into the diagonal, using extenders, putting stuff between the binoviewer and diagonal...every which way. I got focus but had to move my focuser all the way out in some cases and still needed an extender. the best combo I got of these 3 way inserting my full size 2" baader diagonal - then putting in the Televue 2x 2" Powermate with 1.25" adapter, then using a quick connect on the binoviewer to a 1.25" nose and putting that into the powermate. this was still pretty far out and had a weird balance to it. and for those that haven't used it, the Televue 2x powermate is fairly heavy.

 

so I went back to my initial config then putting in the TV 2.25x and an eyepiece on that. (exactly like Denis does in post 1). I had to move my focuser a little bit but not much. then I tried two smaller barlows I had on hand, the Nikon 1.6 EIC and Zeiss Abbe 2x barlow. Both worked great!! I actually had to rack my focuser in a little bit. The nikon is the lightest one and sticks out the least. the Zeiss is in the middle weight and height wise between nikon and TV 2.25x.

 

I tried my main eyepieces and the nikon and zeiss came to focus the easiest. slight edge to the zeiss in terms of ease of use (I just find the clicklock a little easier / smoother to operate). So I am gonna go with a pair of barlows. I'll play around one night when the planets are looking good and decide which I like better.

 

it's also so easy to stick two barlows in vs remove a diagonal and insert something else. I was considering buying a second diagonal and having a GPC in it permanently so I could just swap diagonals...but it's still just way easier to put in two light barlows...and the barlows will be immediately useful for other stuff as opposed to configurations where I unscrewed the powermate and used a T2 adapter.

 

plus my focuser says "thank you" for not putting a heavy load on it fully extended

 

I'll be selling off some of the other barlows / telecentrics so I don't have overlap.

 

moral of the story: listen to Denis in the first place

[balcon3]

As was mentioned above, putting Barlows between the binoviewer and the eyepieces is probably not the best idea if you are using a prism-based Binoviewer (which is most binoviewers), since the Barlows will magnify the uncorrected distortions of the prisms in the Binoviewer. 

Edited by balcon3, 25 June 2025 - 02:32 AM.

[vicuna]

I have Denis’ mirror-based bino-viewer (APO CZAS sharpest). So I think I’ll be ok with that. I’ll keep an eye out though.

 

I still also haven’t tried shorter focal length eyepieces. I have read that it’s harder to see but I see some people using them. That might be my fall / winter project to see if I can go lower. 13mm is my lowest pair of eyepieces right now.

Edited by vicuna, 25 June 2025 - 07:33 AM.