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Binoviewing with A-P Stowaway

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#1 rdjamieson

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Posted 06 February 2024 - 10:29 AM

I will be using my Stowaway (F6.65 iteration) primarily for moon/planets. I already have the Mark V Binoviewer and a matched pair of Panoptic 24mm.  This will be the maiden voyage for both the Stowaway and binoviewer, so I am admittedly a little at sea.  A helpful CNer recently warned me that A-P recommends against binoviewing with eyepieces 12mm and smaller.  So I’m thinking of the following path for higher magnification: Powermate 2x + Mark V + 24mm Pans.  Other than the comical size of the eyepiece arrangement, do you have any issues with this arrangement?  
 

I would also like to have an intermediate magnification between the 24mm Pans with and without the Powermate.  I already have a Nagler 5T16 and a Nagler 6T13.  I am very fond of the 5T16, but that does not mean it will perform well in a binoviewer.  If you do not think either of these hit the sweet spot, what do you recommend?

 

Thanks,

 

Ray



#2 betacygni

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Posted 06 February 2024 - 11:48 AM

That should be a very good setup. The TV powermates give some different magnifications when used with binoviewers, but the 2x model only moves to about 2.2x, which shouldn’t make an issue. The 24mm Panoptics are indeed among the best binoviewer eyepieces available for low to medium powers, you should enjoy them.

16mm Naglers are a bit hit or miss on personal preference. Some find the 82* AFOV too large when binoviewing and hard to take in, others enjoy it. If you already own one not much risk in trying out a second though!

In regards to reaching focus without an amplifier (binoviewers add a lot of extra physical length the light has to travel), this will depend on your precise setup (diagonal in particular), and probably isn’t possible without some sort of amplifier. More than likely you will need at least the 1.25x glasspath corrector, and a low profile t2 Baader diagonal, if you don’t already own these with your Mark V.

Edited by betacygni, 06 February 2024 - 11:50 AM.


#3 betacygni

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Posted 06 February 2024 - 12:01 PM

On a side note with the 2x powermate, you should be able to mount it ahead of the diagonal for a bit more ergonomic setup. I’ve not used one for a long time, but I recall this working when I did (might increase magnification up slightly though).

#4 Bintang13

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Posted 06 February 2024 - 12:37 PM

Hi Ray,

 

When we had our TeleVue 85 we used 18.2mm and 15mm Delite eyepieces. They can be decloaked and are pretty light, balance was an issue. A Celestron 2.5x Barlow yielding approx 4.2x mag turned out to be the sharpest amplifier for this setup. We used the 24 Pans for low power. The TV 85 came to focus using a T2 1.25” Baader diagonal and their 1.25 mag GPC. If using a driven mount I would consider the new Takahashi TPL line.

Best of luck with your decisions.

 

Jim



#5 rdjamieson

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Posted 07 February 2024 - 07:48 AM

betacygni, on 06 Feb 2024 - 10:48
In regards to reaching focus without an amplifier (binoviewers add a lot of extra physical length the light has to travel), this will depend on your precise setup (diagonal in particular), and probably isn’t possible without some sort of amplifier. More than likely you will need at least the 1.25x glasspath corrector, and a low profile t2 Baader diagonal, if you don’t already own these with your Mark V.

Rut roh!  I was aware I needed anything beyond a 2” diagonal. I have a 2” Televue Everbright on hand, and a 2” Maxbright on order for the Stowaway.  Seems like you are saying that with the longer light path, I cannot just put a quarter inch adapter in the diagonal and insert the binoviewer.  If using the Maxbright, what do I all need to get?

 

Thanks!



#6 rdjamieson

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Posted 07 February 2024 - 07:51 AM

Hi Ray,

 

When we had our TeleVue 85 we used 18.2mm and 15mm Delite eyepieces. They can be decloaked and are pretty light, balance was an issue. A Celestron 2.5x Barlow yielding approx 4.2x mag turned out to be the sharpest amplifier for this setup. We used the 24 Pans for low power. The TV 85 came to focus using a T2 1.25” Baader diagonal and their 1.25 mag GPC. If using a driven mount I would consider the new Takahashi TPL line.

Best of luck with your decisions.

 

Jim

Thanks, Jim.  I don’t have any Delites. Maybe I will pick a couple up.



#7 rdjamieson

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Posted 07 February 2024 - 08:30 AM

 Regarding the TPL, I’m ordinarily not very price sensitive, but they seem pretty spendy for a Plossl, yes?  Looks like they are 50 percent more than a comparable Televue.  Am I missing something?



#8 betacygni

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Posted 07 February 2024 - 09:10 AM

Rut roh! I was aware I needed anything beyond a 2” diagonal. I have a 2” Televue Everbright on hand, and a 2” Maxbright on order for the Stowaway. Seems like you are saying that with the longer light path, I cannot just put a quarter inch adapter in the diagonal and insert the binoviewer. If using the Maxbright, what do I all need to get?

Thanks!

Did you already buy/recieve the Mark V binoviewers? They typically come with all the parts you need as the package (say if you’re buying them from Astro-physics for example): https://www.astro-physics.com/bpmarkvs

Binoviewers and standard 2” diagonals don’t normally work together without an amplifier, as the added light path of the binoviewers plus the light path of 2” diagonals is too long to reach focus. It might reach focus with the 2x powermate you already have though.

But again if you bought the full Mark V package above, that includes all you need (t2 diagonal, 1.25x glasspath, etc).

#9 betacygni

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Posted 07 February 2024 - 09:14 AM

Regarding the TPL, I’m ordinarily not very price sensitive, but they seem pretty spendy for a Plossl, yes? Looks like they are 50 percent more than a comparable Televue. Am I missing something?

Plossls can perform better on planetary than complex multiple element designs like Naglers, panoptics, and even Delites. The TPLs are essentially high end, well executed Plossls. Some report slightly better planetary views through them, some don’t. I’m one of those that see the benefit, but it’s admittedly subtle. With eyepieces you’ll notice there is a lot of individual preference/unique eyes/conditions/scopes etc at play that doesn’t always make a given eyepiece objectively better than another.

Edited by betacygni, 07 February 2024 - 09:17 AM.

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#10 RAKing

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Posted 07 February 2024 - 10:02 AM

In regards to reaching focus without an amplifier (binoviewers add a lot of extra physical length the light has to travel), this will depend on your precise setup (diagonal in particular), and probably isn’t possible without some sort of amplifier. More than likely you will need at least the 1.25x glasspath corrector, and a low profile t2 Baader diagonal, if you don’t already own these with your Mark V.

 

You might have to do some experimenting to find out which GPC works with the Stowaway.  With my older Traveler, I had to use a 1.7x GPC because the Traveler didn't have enough backfocus with the 1.25x.

 

With any BV, you should immediately scrub the 2-inch diagonal.  The Mark V binos are a perfect fit with the Baader T2 diagonals - and I now prefer the BBHS mirror version.  This is my Mark V on the back of my TSA-120:

 

TSA-120 Baader VB.JPG

 

The GPC fits into the nose of the Mark V BV and the BV attaches to the diagonal with a Baader QC (Quick Connect) fitting.  This provides the shortest light path and should allow you to focus with no issues.  BTW - All of this stuff is included with the standard Baader Mark V kit, but if you bought your Mark V on the used market, you can get all of these parts separately.

 

For eyepieces - your eyes will be the judge of what eyepieces work best!  Roland's suggestion is merely that: a suggestion.  Personally, I am very happy with shorter focal lengths, and I regularly go all the way down to a pair of 5mm T6 Naglers with my TSA.  With the 1.25x GPC, those eyepieces are effectively 4mm and produce 225x in my Tak.  The 24 Panoptics work great for me, as do the 16T5 and my pairs of T6 Naglers.  I am primarily a double star / variable star observer, so high magnifications are sometimes necessary to split the tighter doubles, and my limits are ruled by the seeing conditions.

 

But again, your eyes will be your judges. waytogo.gif

 

Ron


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#11 Bintang13

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Posted 07 February 2024 - 10:53 AM

Hi Ray,

 

No doubt about price of the TPL.  It’s actually less expensive though than the Takahashi 18mm LE eyepieces, supposedly better. Those are one of the eyepieces I regret selling. Would not have if we kept a driven mount. Thought they deserved considering. Regarding your 2” diagonal, you are going to need an amplifier to reach high magnification anyway with your scope you might be fine with the powermate that you have, as mentioned earlier, if not after the diagonal but certainly before the diagonal. The shortest light path, 1.25” T2 diagonal with shortest couplers, will require the least amplification for your system. It may be short enough not to require any amplification. The TV85 was just short of coming into focus without. It required the 1.25 mag Baader GPC. That determined the lowest power I could achieve.  
 

Jim



#12 Bintang13

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Posted 07 February 2024 - 11:28 AM

The shortest light path is also much lighter than a 2” diagonal and powermate combination which helps with balance especially with shorter scopes and puts less stain on the focuser.



#13 betacygni

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Posted 07 February 2024 - 01:16 PM

You might have to do some experimenting to find out which GPC works with the Stowaway. With my older Traveler, I had to use a 1.7x GPC because the Traveler didn't have enough backfocus with the 1.25x.

I’m going off memory here, but a believe the 1.25x glasspath reaches focus with the stowaway. But again my memory shouldn’t be 100% trusted!
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#14 RAKing

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Posted 07 February 2024 - 01:33 PM

I’m going off memory here, but a believe the 1.25x glasspath reaches focus with the stowaway. But again my memory shouldn’t be 100% trusted!

 

Yup!  That is my problem, too!  I don't even know if the new Stowaway is identical to the original - and my memories are about 15 years old about the Stowaway already.  <LOL>  I just sold my Traveler last year, so that memory is fresher.

 

And one of the reasons I went back to my Taks is they both can use the 1.25x GPC, which makes my focal calculations easier.

 

Ron


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#15 rdjamieson

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Posted 07 February 2024 - 03:38 PM

Thanks for your advice.  I chatted with Greg at A-P, and ordered one of those compensators today. He said I’d be fine with the 2” diagonal is I used the compensator.



#16 ckwastro

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Posted 07 February 2024 - 04:07 PM

I’ve been binoviewing with a Stowaway for 20 years. I don’t have the Baader MkV but do have a Denkmeier with a 2x Power Switch (PS). The OCS is designed to thread into the field end (in front) of the 2” diagonal and produces 1.2x. So the system is 1.2x with the PS in the normal position and 2.4x when engaged. I’ve used both a 2” MaxBright and a 2” TV Everbrite. No problems with either 2” diagonal and I’ve never had an eyepiece not reach focus, even with the 1.2x setting. 
 

BTW my 2002 Stowaway is f/6.57 despite originally having been marketed as f/7. The focal length is 604mm. Hopefully the Baader 1.25x configuration will yield similar results for you. Good luck! 


Edited by ckwastro, 07 February 2024 - 04:10 PM.

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#17 rdjamieson

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Posted 07 February 2024 - 08:39 PM

Thanks, Kerry!  I can’t wait! I’m 


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#18 Jeff B

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Posted 09 February 2024 - 02:08 PM

Ray, my recent run AP Stowaway is excellent for bino-viewing.  But it is not "bino-friendly", meaning a barlow device of some sort  is necessary to get to focus with low power eyepieces.   It comes close to bino-friendly in stock form only with my Mark V and Baader Zeiss spec T2 prism diagonal.  Using the cheaper Baader T2 prism diagonal will give you about 3.5mm of extra back focus over the Zeiss spec diagonal and using the Baader MaxBright viewer over the Mark V will add another 3mm of back focus.  But that extra ~6.5mm of back focus is still not enough to make the Stowaway bino-friendly, at least not the sample I have.

 

However, I didn't give up.   I unscrewed the AP stock visual back from the draw tube of the FT focuser and replaced it with one of these:

 

https://www.astro-physics.com/ada20132

 

modified by a small local machine shop so that it screws directly into the FT draw tube.  The "system" (Stowaway, Zeiss spec T2 prism diagonal and Baader MKV viewer) now comes to focus at the top of the MKV's collets with 3mm to "spare", which is just barely enough to allow my good old Ultima 30mm pair to focus. Switching diagonals to the cheaper Baader T2 diagonal and MaxBright II viewer would give about another 6mm of extra in-travel.  While not hugely more, it may be enough to allow some flexibility in low power eyepieces. 

 

Now this is a very specific, basically niche, low power bino-friendly configuration which avoids a GPC.  But it gets me "there" with my Stowaway.  That was important to me.

 

Ray, as you already have the MKV, you would need the modified AP adapter and the cheaper Zeiss T2 prism diagonal and you just might get "there" with 24mm Pans, especially if they focus a little further out than my Ultimas.

 

I've added some pictures.

 

Jeff

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  • Stock AP Thin and Modified.jpg
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  • Mod Adapter Installed.jpg
  • Bino Friendly MKV, 30MM Ultimas.jpg

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#19 rdjamieson

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Posted 09 February 2024 - 03:47 PM

Jeff, this is excellent.  I will let you know what happens, and it looks like I will be purchasing another diagonal. Doh!


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#20 rdjamieson

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Posted 13 February 2024 - 05:14 AM

Progress.  I just picked up a pair of Panoptic 19s to go with the 24s.  Also, I obtained a complete set of the Fujiyama OR-HDs.  If I like them one-eyed, I may grab a second set to go with the BVs.  Any concerns about that, especially re eye relief?  I don’t wear glasses while observing, but I’ve read that the short FLs can get tight. 
 

I’m holding off on a second Nagler Type 5 16mm.  As much as I love the eyepiece, member experience with it in a BV seems a bit mixed.  Perhaps a second Nagler Type 6 13mm, or second Panoptic 15mm.

 

Waiting for my A-P package to arrive, along with some clear skies.  Then I will finally put this thing together and give it a try.

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#21 betacygni

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Posted 13 February 2024 - 02:33 PM

Looks like you’re off to a great start, all those eyepieces should work exceptionally well!

The Naglers are indeed a very personal preference. Most find the 60-70 degree AFOV ideal binoviewing, because unlike mono you can’t move your head around to see the edges of the FOV with both eyes having to stay on each exit pupil. I’ve recently enjoyed my 85* Masuyamas, but the larger AFOV is mainly for framing, you can’t really directly look at the edges unlike with mono.

#22 RAKing

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Posted 13 February 2024 - 04:46 PM

Hmmm, maybe I am different, but I don't have any trouble with my Naglers.

 

I like to estimate variable stars, and most of the time, the comparison stars are some distance away from the variable.  They are within the actual 3-degree views I have with my AAVSO charts, but most of them are not side-by-side, so there is some shifting of focus needed to enjoy this facet of our hobby. 

 

But I don't have any trouble focusing my attention to different places within that wide view as I shift my focus looking back and forth to compare those stars - and I certainly don't feel like I am forced to "lock" my head in one spot as I am viewing.  The entire FOV is focused within the exit pupil and as long as you stay relaxed, you can enjoy the entire view.

 

Maybe it's because I have been doing this for so many years, but I love the wider views I get with the Naglers.  I also love my little Panoptics, but the old 15mm was not as good for me as the 16T5 Nagler, so it "left the building" many years ago. 

 

I hope you get your gear and some decent weather soon, so you can see things for yourself!  waytogo.gif

 

Ron


Edited by RAKing, 13 February 2024 - 04:47 PM.

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#23 betacygni

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Posted 13 February 2024 - 06:25 PM

Hmmm, maybe I am different, but I don't have any trouble with my Naglers.

I like to estimate variable stars, and most of the time, the comparison stars are some distance away from the variable. They are within the actual 3-degree views I have with my AAVSO charts, but most of them are not side-by-side, so there is some shifting of focus needed to enjoy this facet of our hobby.

But I don't have any trouble focusing my attention to different places within that wide view as I shift my focus looking back and forth to compare those stars - and I certainly don't feel like I am forced to "lock" my head in one spot as I am viewing. The entire FOV is focused within the exit pupil and as long as you stay relaxed, you can enjoy the entire view.

Maybe it's because I have been doing this for so many years, but I love the wider views I get with the Naglers. I also love my little Panoptics, but the old 15mm was not as good for me as the 16T5 Nagler, so it "left the building" many years ago.

I hope you get your gear and some decent weather soon, so you can see things for yourself! waytogo.gif

Ron

Maybe you just have eye stalks lol.gif

So you can look at the very edge of the FOV with direct vision and don’t lose the exit pupil with the other eye? The way I experience it as the pupil moves to the side it’s going to lose the exit pupil (unless you can move your head to compensate keeping it centered like in mono, which you can’t with the other eye also trying to keep on the exit pupil). I can see most the FOV with peripheral vision, just can’t use direct vision towards the edges, eyes have to stay roughly forward looking for me.

Edited by betacygni, 13 February 2024 - 06:29 PM.


#24 rdjamieson

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Posted 15 February 2024 - 09:09 AM

Do you break down and put away your binoviewer every time?  I’m trying to streamline my set up time as much as I can, and it would save time if I left the binos and a couple EPs in place on the Stowaway all the time.  However, I’m accustomed to everything being in its place, and psychologically it feels wrong not to put everything away between viewings because, as I’ve drummed into my kids, nice things that aren’t put away get broken, dirty, etc.  Thoughts?



#25 betacygni

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Posted 15 February 2024 - 01:44 PM

Do you break down and put away your binoviewer every time? I’m trying to streamline my set up time as much as I can, and it would save time if I left the binos and a couple EPs in place on the Stowaway all the time. However, I’m accustomed to everything being in its place, and psychologically it feels wrong not to put everything away between viewings because, as I’ve drummed into my kids, nice things that aren’t put away get broken, dirty, etc. Thoughts?

I keep my binoviewers assembled (eyepieces in, amplifier still on, and still even diagonal on sometimes). I treat them essentially as large eyepieces.

You could keep it on scope in theory, but I don’t see a reason to as it only takes seconds to attach the binoviewer. It’s also generally not advisable to transport a scope still mounted, too many door jams, things to trip over, etc.


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