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RAKing
Postmaster

Reged: 12/28/07

Loc: West of the D.C. Nebula
Re: Leica ASPH Zoom in a Fast Newtonian [Re: sixela]
#5482386 - 10/21/12 05:34 PM

Quote:

Yes, I know about yours, but even that will yield a factor of 1.43x with a BarAdv (4,5mm from focal plane to shoulder, 28mm for your adapter, and 12mm from the threads of the BarAdv to its principal plane, the sum divided by 102mm, and then +1).

And yours is shorter than the commercial ones I know. I'm simply puzzled by what RAKing and Bob S. are doing.

If I remember the Barcon element well, it doesn't fit inside a 2" barrel, so it's bound to end up a lot further from the eyepiece's focal plane. Or does it have different housings, one of which is more narrow than a 2" barrel andallows it to go into Markus's 2" adapter?

Reading this again, it looks like I went the wrong way with one of my measurements.

Recalculating............. Now the math gives me 116mm as the focal length for the Barcon and if you screw the Barcon directly to the base of my adapter, it calculates to 1.2x.

If I add up the components for my current spacers, I now get 1.52x - which is still good for me.

Hope this helps,

Ron

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sixela
Postmaster

Reged: 12/23/04

Loc: Boechout, Belgium
Re: Leica ASPH Zoom in a Fast Newtonian [Re: RAKing]
#5482417 - 10/21/12 05:48 PM

Which adapter is it? As I said, mine is 42.5mm long so if the 2" BarAdv is simply at the end of it, it's quite far from the Leica's focal plane.

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RAKing
Postmaster

Reged: 12/28/07

Loc: West of the D.C. Nebula
Re: Leica ASPH Zoom in a Fast Newtonian [Re: sixela]
#5482436 - 10/21/12 06:01 PM

Quote:

Which adapter is it? As I said, mine is 42.5mm long so if the 2" BarAdv is simply at the end of it, it's quite far from the Leica's focal plane.

I don't know. It's the one that Markus supplied with the eyepiece. It's a nice unit, with three long grub screws, and it is much shorter than the one you have. You are closer to him, I suggest you give him a shout and see if you can get one.

The Barcon will not fit all the way into this adapter -- but you must keep in mind that the lens of the Barcon is set about 5mm before the threads end. Thus, it is possible to screw the Barcon partially into this adapter and that is where the close proximity issue between the Barcon and the Leica's field lens retainer occurs.

So if I ran my numbers: 4.5mm to focal plane + 25mm adapter - (minus) 5mm to principal plane divided by 116mm focal length, I get 0.211. Add 1 for 1.21x. Does this sound correct?

Cheers,

Ron

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Bob S.
Carpal Tunnel

Reged: 07/14/05

Re: Leica ASPH Zoom in a Fast Newtonian [Re: sixela]
#5482446 - 10/21/12 06:05 PM

Astro Buds, I had done some sky meter readings this morning when I bagged the 15th magnitude I star in the trap. The SQM reading on my sky meter was 20.92 that Cruxis translated into a Naked Eye Limiting Magnitude of 6.4 and Telescope Limiting Magnitude of 15.2 mag. The Leica ASPH coupled with a superb Lockwood primary/secondary was able to present a point of light that was only .2 below its theoretical limit. This boggles my mind because I am currenlty fighting a healthy dose of cataract problems with my eyes that was recently diagnosed and yet my eye was able to discern this faint point of light with the help of superb optics and very pleasant eye relief. Andreas observations about this eyepiece being as good as a Zeiss Abbe Ortho II is certainly gaining credence in my book<g>. I was, during parts of this observing session, using a pair of 16mm ZAO II's in a Baader Mark V and the views were brilliantly neutral renditions of the planet with a light blue festoon and tons of white ovals linked in one of the equatorial bands. I don't think they will be going anywhere because unlike Tammy, there is no way that my IPD would allow for binoviewing ASPH's. Bob

Edited by Bob S. (10/21/12 06:27 PM)

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johnnyha
Postmaster

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Leica ASPH Zoom in a Fast Newtonian [Re: Bob S.]
#5482449 - 10/21/12 06:07 PM

My wallet will not allow binoviewing with ASPHs.

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RAKing
Postmaster

Reged: 12/28/07

Loc: West of the D.C. Nebula
Re: Leica ASPH Zoom in a Fast Newtonian [Re: Bob S.]
#5482459 - 10/21/12 06:12 PM

Naked eye = 6.4? I can only wish!

I alert the media when I get 4.8.

I am sitting here holding my zoom because of the calculations and it would be awesome to bino a pair of these.

I have the cataracts, plus I have a condition called "asteroid hyalosis", yet I was able to pick out a mag. 12.5 comp star with my 130mm refractor the other night using this eyepiece. I was very happy with its performance.

Cheers,

Ron

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sixela
Postmaster

Reged: 12/23/04

Loc: Boechout, Belgium
Re: Leica ASPH Zoom in a Fast Newtonian [Re: RAKing]
#5482481 - 10/21/12 06:28 PM

Yes, if your adapter is 2cm shorter and if the Barcon's M48 thread is that long that explains a lot.

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andydj5xp
Pooh-Bah

Reged: 05/27/04

Loc: 52.269 N/10.571 E
Re: Leica ASPH Zoom in a Fast Newtonian [Re: Bob S.]
#5483071 - 10/22/12 04:13 AM

Quote:

Astro Buds, I had done some sky meter readings this morning when I bagged the 15th magnitude I star in the trap. The SQM reading on my sky meter was 20.92 that Cruxis translated into a Naked Eye Limiting Magnitude of 6.4 and Telescope Limiting Magnitude of 15.2 mag. The Leica ASPH coupled with a superb Lockwood primary/secondary was able to present a point of light that was only .2 below its theoretical limit. This boggles my mind because I am currenlty fighting a healthy dose of cataract problems with my eyes that was recently diagnosed and yet my eye was able to discern this faint point of light with the help of superb optics and very pleasant eye relief. Andreas observations about this eyepiece being as good as a Zeiss Abbe Ortho II is certainly gaining credence in my book<g>. I was, during parts of this observing session, using a pair of 16mm ZAO II's in a Baader Mark V and the views were brilliantly neutral renditions of the planet with a light blue festoon and tons of white ovals linked in one of the equatorial bands. I don't think they will be going anywhere because unlike Tammy, there is no way that my IPD would allow for binoviewing ASPH's. Bob

Thanks for the beautiful reports, Bob.

How about starting another thread labeled "Leica ASPH Zoom in a TEC 160FL"? This combo will be as close to perfection as possible.

Andreas

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ausastronomer
Carpal Tunnel

Reged: 06/30/03

Loc: Kiama NSW (Australia)
Re: Leica ASPH Zoom in a Fast Newtonian [Re: andydj5xp]
#5483074 - 10/22/12 04:16 AM

Is the Leica ASPH zoom suitable for use with eyeglasses ? What is the eye relief stated as ?

That's a deal breaker for me. Gotta be able to use it easily with glasses on.

Cheers

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johnnyha
Postmaster

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Leica ASPH Zoom in a Fast Newtonian [Re: ausastronomer]
#5483077 - 10/22/12 04:24 AM

ER is stated as 18mm.

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andydj5xp
Pooh-Bah

Reged: 05/27/04

Loc: 52.269 N/10.571 E
Re: Leica ASPH Zoom in a Fast Newtonian [Re: ausastronomer]
#5483096 - 10/22/12 04:53 AM

Quote:

Is the Leica ASPH zoom suitable for use with eyeglasses ? What is the eye relief stated as ?

That's a deal breaker for me. Gotta be able to use it easily with glasses on.

Cheers

I've measured the eye relief to be between 19mm to 17mm. See here

But there are also measurement results obtained by BillP to be between 16mm and 13mm (scroll up the link).

Therefore, it's still a bit mysterious.

Andreas

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Bob S.
Carpal Tunnel

Reged: 07/14/05

Re: Leica ASPH Zoom in a Fast Newtonian [Re: andydj5xp]
#5483144 - 10/22/12 06:26 AM

Quote:

Quote:

Astro Buds, I had done some sky meter readings this morning when I bagged the 15th magnitude I star in the trap. The SQM reading on my sky meter was 20.92 that Cruxis translated into a Naked Eye Limiting Magnitude of 6.4 and Telescope Limiting Magnitude of 15.2 mag. The Leica ASPH coupled with a superb Lockwood primary/secondary was able to present a point of light that was only .2 below its theoretical limit. This boggles my mind because I am currenlty fighting a healthy dose of cataract problems with my eyes that was recently diagnosed and yet my eye was able to discern this faint point of light with the help of superb optics and very pleasant eye relief. Andreas observations about this eyepiece being as good as a Zeiss Abbe Ortho II is certainly gaining credence in my book<g>. I was, during parts of this observing session, using a pair of 16mm ZAO II's in a Baader Mark V and the views were brilliantly neutral renditions of the planet with a light blue festoon and tons of white ovals linked in one of the equatorial bands. I don't think they will be going anywhere because unlike Tammy, there is no way that my IPD would allow for binoviewing ASPH's. Bob

Thanks for the beautiful reports, Bob.

How about starting another thread labeled "Leica ASPH Zoom in a TEC 160FL"? This combo will be as close to perfection as possible.

Andreas

Andreas, I have yet to put the ASPH in my TEC 160FL. With 16.5" of aperture vs. 6.2", it is sometimes difficult to carry the refractor down from my study and mount it. However, I need to see the magic of the ASPH in the TEC for sure! I have not compared the ASPH monocularly with the Zeiss because I have been playing so hard with e Baader Mark V's. For lunar/planetary observation, I am finding that what I give up in light throughput and sheer monocular resolution is made up for and then some on the planets/Moon with binovision. I promise in the weeks to come to get that beautiful Leica into my beautiful refractor. Bob

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RAKing
Postmaster

Reged: 12/28/07

Loc: West of the D.C. Nebula
Re: Leica ASPH Zoom in a Fast Newtonian [Re: sixela]

Folks,

Sixela asked me to take a picture of my Leica zoom with the adapter and I think it might help clarify things if I go ahead and post the picture.

It shows the Leica Zoom with the 25mm adapter, plus I included the A-P Barcon in the shot.

The inner threads on the Barcon are T2 and the outer threads are M48. The Barlow lens inside the barcon sits about 5mm "up" from where the M48 threads end at the main body.

It's also worth noting that the Leica field lens is only about 5mm "up" from the bottom of the adapter. It's possible to get the Barcon and the Leica in very close proximity.

Hope this helps explain things in this thread.

Cheers,

Ron

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johnnyha
Postmaster

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Leica ASPH Zoom in a Fast Newtonian [Re: RAKing]
#5484013 - 10/22/12 05:05 PM

Thanks Ron!

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johnnyha
Postmaster

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Leica ASPH Zoom in a Fast Newtonian [Re: johnnyha]
#5487498 - 10/24/12 07:10 PM

I received my used AP Barcon today, still waiting on the Leica Zoom. However I though it was worth noting, the AP Barcon barlow element does not jive with the Televue 2" barrel extender's "universal filter threads". I can screw it in one revolution and then it sticks. This jives with my other Televue stuff, it is not actually universal and appears to be proprietary to TV filters, etc idea of what filter threads are. The Barcon is usable on the TV barrel extender but I suspect the same will be true when I get the Leica, the barrel extender will undoubtedly not screw into the Leica's filter threads fully, since it is slightly different. I'll probably just get a T2 extension and adapt it to the Leica filter threads or use the Leica Zoom in the native 1.7X AP Barcon. Unfortunately though while the length is perfect, I am not satisfied with the TV 2" barrel extender as a way to achieve 1.5X with the Leica Zoom.

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sixela
Postmaster

Reged: 12/23/04

Loc: Boechout, Belgium
Re: Leica ASPH Zoom in a Fast Newtonian [Re: johnnyha]
#5487562 - 10/24/12 08:00 PM

Got a short adapter from Markus.

If anyone wants an unused longer one, PM me.

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ohioalfa64
super member

Reged: 08/16/12

Loc: Ohio
Re: Leica ASPH Zoom in a Fast Newtonian [Re: sixela]
#5487713 - 10/24/12 09:49 PM

How does an outsider obtain the shorter 25mm Markus adaptor?

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sixela
Postmaster

Reged: 12/23/04

Loc: Boechout, Belgium
Re: Leica ASPH Zoom in a Fast Newtonian [Re: ohioalfa64]
#5488047 - 10/25/12 04:24 AM

You just buy it. It's listed on his web site for €60 (and less for people who don't pay VAT).

Markus tells me he no longer makes the long adapter (I have one to sell to anyone interested; if you don't plan to screw on a barlow it's a bit better to register the eyepiece in the focuser, as the new adapter is frighteningly short for such a large eyepiece; but of course extending that small barrel is trivial while taking a saw to the old longer one is more frightening).

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sixela
Postmaster

Reged: 12/23/04

Loc: Boechout, Belgium
Re: Leica ASPH Zoom in a Fast Newtonian *DELETED* [Re: ohioalfa64]
#5488050 - 10/25/12 04:28 AM

Post deleted by sixela

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johnnyha
Postmaster

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Leica ASPH Zoom in a Fast Newtonian [Re: sixela]
#5488059 - 10/25/12 04:59 AM

I have a question - does the current 2" adapter have just standard 48mm filter threads or does it have a T2 thread as well?

Arg - OK I see Markus offers two separate 2" adapters, 48mm and T2. I did not specify so I bet i got the 48mm. Shoulda got the T2.

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