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A-P BARCON was discontinued...

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#1 DaveJ

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Posted 24 October 2012 - 03:58 PM

Yes, the Astro-Physics BARCON was dropped from the lineup right about the time I needed one. I tried finding one at Astromart and the CN classifieds without success. Bummer. HOWEVER, yesterday I again checked the A-P Website and, lo and behold, a brand spanking new version is available - the newly designed by Roland Christen for a flatter field 2" Advanced Convertible Barlow (BARADV) for the same price, I believe, as the BARCON. Thought some others here might be interested since the BARCON was the Barlow of choice for the Mark V binoviewers. I called A-P and spoke to George about it. He assured me that the BARADV will do everything as well as the BARCON for visual, but is much improved over the BARCON for photographic purposes.

#2 johnnyha

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Posted 24 October 2012 - 06:03 PM

I recieved my used AP Barcon today that I bought from classifieds, in excellent condition. As I suspected from owning one previously, the AP filter threads on the Barcon element do not jive with the "universal filter threads" on my Televue 2" barrel extender. For all I love TV, their filter threads *always* seem to be proprietary! I can screw the Barcon in one or two revolutions but that's it.

#3 junomike

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Posted 24 October 2012 - 06:30 PM

Johnny, I use this for my TV Binoviewer and It works great. Maybe the Barcon will thread into this easier than the TV extension?
Not sure?

Mike

#4 johnnyha

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Posted 24 October 2012 - 08:06 PM

Thanks Mike. I have one of those but I don't think the T2 nosepiece will screw into the Leica adapter...? Without a filter thread to T2 adapter...

#5 George9

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Posted 24 October 2012 - 08:20 PM

I have a BARADV already on the way and will check the new threads. George

#6 johnnyha

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Posted 24 October 2012 - 08:57 PM

The Barcon threads are fine. Mine screwed into the Baader diagonal prism perfectly. My thesis is that Televue's "filter threads" are not the same as the universally excepted 48mm "filter threads". I also have a problem screwing my Lumicon OIII filter into the Televue barrel extension's filter threads.

#7 George9

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Posted 28 October 2012 - 03:08 PM

I got the BARADV. Seems to work well. I got it for my Denk II's, mainly for a Lunt solar scope. Really just a more portable way to go to higher power (as opposed to carrying two more eyepieces).

The T2 male thread extension in front of the 48mm male thread (on the eyepiece end of the BARADV) prevent you from attaching it to the Denk OCS or other devices directly, but the 1/2 inch long 48mm extension tube that Russ of Denk sent me fixes that.

I really wish the BARADV had 48mm female threads on the objecive end so you could throw on a filter when you want. Instead there is nothing.

George

#8 sixela

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Posted 28 October 2012 - 05:55 PM

What threads are on the inside of the retaining ring on the objective side? Or are these simply grooves for baffling?

#9 George9

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Posted 28 October 2012 - 07:37 PM

Excellent point. I measure almost exactly 1.5 inches, or around 38mm inside the retaining ring. So the male thread would be maybe 39mm. It's not a T2. The threads inside the ring appear to be painted flat black and have some burrs, so I think they were never intended to be used as threads. Normally AP produces shiny, perfect threads. I guess it would be possible to rig up an adapter.

The other choice would be to replace the retaining ring with a shorter one (it's now 1/4 inch long). The outer threads of the retaining ring appear to be 46mm rather than 48, so you would need an adapter there, too.

Yet another choice, if you have backfocus, would be to screw the eyepiece end of the BARADV into the previous element (say the diagonal) leaving the BARADV's 2" adapter free. Put the objective end of the BARADV into the eyepiece side of the adapter, and the objective end of the adapter does have a 48mm thread.

George

#10 George9

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Posted 30 October 2012 - 05:36 PM

I sent a message to George of Astro-Physics, who spoke with the owner, Roland. They'll consider the 48mm thread on the next iteration, but it can't be for a while. Either way, I am happy with the performance.

George

#11 Tamiji Homma

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Posted 02 November 2012 - 06:09 PM

I got Advanced BARCON this week.

New one has a little higher magnification factor than original BARCON.
1.50x BARCON->AP16T->Starlight Leica adapter -> Leica Zoom
1.62x ADV-BARCON->AP16T->Starlight Leica adapter -> Leica Zoom

It is hard to tell visually that Advanced BARCON is flatter/better edge than original BARCON.

Posted Image

Tammy

#12 Paraclete

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Posted 02 November 2012 - 07:13 PM

Hi Tammy. I hope you don't mind me quoting you from the eyepiece forum:

With barcon, outer 10% becomes a little bit murky/mushy due to field curvature.


So you don't see any improvement with the new BARADV?

#13 Tamiji Homma

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Posted 02 November 2012 - 09:12 PM

Hi Tammy. I hope you don't mind me quoting you from the eyepiece forum:

With barcon, outer 10% becomes a little bit murky/mushy due to field curvature.


So you don't see any improvement with the new BARADV?


The comment above was with Paragon 40 and Televue Plossl 32, I think. I was testing long focal end of Leica and Meopta Zoom eyepiece along with BARCON/ADV-BARCON.

I retested with Paragon 40/Televue Plossl and Vixen ED80SF f/7.5. I did see edge improvement of Advanced BARCON over original BARCON.

I'll try flat field scopes (TSA-102S+35FL, FS-60Q) later.

Tammy

#14 10gauge

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Posted 04 November 2012 - 10:43 AM

Hello Tammy, the previous Barcon had a stated magnification of 2.4X, but you measured 2.2X in a scope. Based on your ratios, I am guessing the magnification of the new BaradV might be around 2.3X. Have you measured the actual magnification of the new BaradV like you did for the previous Barcon in the following chain:

BaradV -- AP16 -- T2P -- QC -- MkV -- EP

Thanks

#15 Tamiji Homma

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Posted 04 November 2012 - 12:47 PM

Here is Barlow factor measurement with MarkV/Panoptic 24.
Base is with GPC 1.25x in place.

   1.00x AP16T-T2P-QC-1.25x-MarkV-Pano24
   2.28x BARCON-AP16T-T2P-QC-1.25x-MarkV-Pano24
   2.68x ADV_BARCON-AP16T-T2P-QC-1.25x-MarkV-Pano24

T2P: T2 Prism Star Diagonal
QC:  Baader Quick Changer
AP16T: Astro Physics T2 2" nosepiece

Following is BARCON/ADV_BARCON + 2" adapter + 6mm height 1.25" adapter + Nikon NAV SW 17.5
   1.00x NAV-SW-17.5 
   1.63x NAV-SW-17.5-BARCON-2"_ADP+1.25_5mm_ADP-NAV-SW-17.5
   1.79x NAV-SW-17.5-ADV_BARCON-2"_ADP+1.25_5mm_ADP-NAV-SW-17.5

Tammy

#16 10gauge

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Posted 04 November 2012 - 09:22 PM

Thank you, Tammy. Based upon a thread from last year about the Mk V bino, GPCs, and Barcon, I had compromised a chart of common magnification factors based upon your data from that thread. Here are the possible magnification factors:

1.00x AP16T-T2P-QC-MkV-EP
1.19x AP16T-T2P-QC-1.25xGPC-MkV-EP
1.42x AP16T-T2P-QC-1.7xGPC-MkV-EP
2.20x 2"EXT*-Barcon-AP16T-T2P-QC-MkV-EP
2.70x 2"EXT*-Barcon-AP16T-T2P-QC-1.25xGPC-MkV-EP
3.09x 2"EXT*-Barcon-AP16T-T2P-QC-1.7xGPC-MkV-EP
3.67x Barcon-2"EXT-AP16T-T2P-QC-1.7xGPC-MkV-EP

* Use 3.6" Extension if insufficient back focus @ high mag EP


They do differ from what you just posted, I am curious if you revised your data since?...
Are you including the Extension in your data?...
I wonder what the magnification factors would be with the BaradV in the above possible scenarios?...

Thanks,
George

#17 Tamiji Homma

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Posted 04 November 2012 - 09:54 PM

   1.00x AP16T-T2P-QC-1.25x-MarkV-Pano24
   2.28x BARCON-AP16T-T2P-QC-1.25x-MarkV-Pano24
   2.68x ADV_BARCON-AP16T-T2P-QC-1.25x-MarkV-Pano24

T2P: T2 Prism Star Diagonal
QC:  Baader Quick Changer
AP16T: Astro Physics T2 2" nosepiece

This measurement does not use 2" extension tube. I usually don't use 2" extension tube with T2 Prism Star Diagonal.
New measurement is without 2" extension tube.
Scope -> BARCON -> AP16T -> T2P -> QC -> 1.25xGPC -> MarkV -> Pano 24
Scope -> ADV_BARCON -> AP16T -> T2P -> QC -> 1.25xGPC -> MarkV -> Pano 24

Tammy

#18 10gauge

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Posted 04 November 2012 - 10:29 PM

Thank you, Tammy, for the prompt response! I will revise my chart. I didn't order the 2.6x GPC, but will order the new BaradV instead. I already have the 1.25x and 1.7x. The new MkV that I have has the mirror diagonal, instead of the prism - after waiting a whole year, Astro-physics made excuses for supplying the mirror diagonal because they couldn't secure the prism diagonal in sufficient numbers.






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