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Posts Made By: Milton Wilcox

October 7, 2002 07:29 PM Forum: Astro Binoculars

High-End Binoculars Revisited

Posted By Milton Wilcox

Frustration over my inability to find a binoviewer that can preserve the FOV as well as image quality of my TV101 has brought me into this forum. FYI, my other binoculars are 1) 25yr. old Nikon 12x36 that have excellent optics but small aperture and unmountable and 2) Canon 18x50IS that I really enjoy when traveling but lack the image quality of the Nikons or TV.

I found several threads from this summer very interesting, like the one on the Kowa Highlander 32x82. This seems to be a unique binocular, with 45deg. viewing, f/5.5 and excellent FOV for its telescope-like power. The obvious downside is the very high price, and no one mentioned the extra $1k for its mount that would undoubtedly require custom work to fit to my Losmandy tripod...

So does it deliver the goods? Do you Markus or anyone else have any observing experiences to report?

Other helpful threads compared the Takahashi 22x60, Fujinon 16x70 and Miyauchi 20x77. With 45deg. viewing, the Miyauchi 20x77 seems like an incredible bargain compared to the Highlander. However, I don't believe it is available in an apo version and the FOV seems low for its power (as with the Tak). Oberwerk was also mentioned, but they seem to weigh twice as much as anything else. Then there's Borg (some assembly required).

Has anyone heard of anything new on the horizon? It seems there are many more choices for one eye than for two!

Thanks, Milt

November 3, 2002 02:56 PM Forum: Astro Binoculars

KOWA HIGHLANDER EP QUESTIONS/COMMENTS

Posted By Milton Wilcox

Can anyone tell me what the third EP set is for the Kowa Highlander? Neither the Kowa nor Anacortes websites list anything other than the 32x and 50x EP's. There is a 27x listed under the 82mm spotting scope, but it has a narrower FOV than the 32x, so what's the point?

It's too bad Kowa chose not to use 1-1/4" EP holders, likely because of weather-proofing that I could care less about (someone should tell Kowa that we don't look through astro binoculars in the rain). For the outrageous price of their 50x EP's, one could buy a pair of 9mm Nagler T6's, get 25% more FOV and $190 in change. A pair of the new 24mm Panoptics would yield a gorgeous 3.6 deg. FOV.

If Kowa offered 1-1/4" EP compatibility in the Highlander, I wouldn't even be considering Vixen.

Milt

December 21, 2002 09:58 AM Forum: Astro Binoculars

Markus, Any Luck With Kowa?

Posted By Milton Wilcox

Hi Markus,

I am following up on your quest to get Kowa to increase the power on the Highlander.

You have probably already thought of this, but rather than asking them to modify the focusers, do you think they could do an adapter with a male end the same as their EP's and a female end designed to take standard 1-1/4" EP's?

Because this would move the EP further away from the body, a negative correction lens would be required in the adapter to achieve focus. However, any increase in power would not be a problem because this is what you are looking for anyway. (Kowa already has the low power end nicely covered with the 21x 3deg. EP)

What do you think? These types of suggestions probably carry more weight when coming from a dealer.

George, if you are reading, have you received your Highlanders yet?

Merry Christmas, Milt

January 5, 2003 10:07 AM Forum: Eyepieces

Observing Report 24 vs 22 Panoptics

Posted By Milton Wilcox

I recently received my new 24Pan from ATWB (<1 wk!) The following comparisons used my only scope, a TV-101 (4" f/5.4). To start with, there are several non-optical advantages for the 24Pan: Parfocal with most other TV EP's, less than half the weight of the 22Pan, compact size, and a more comfortable (for me) smaller diameter eye cup.

My observing was done over two mild (45F) clear nights in AZ. Reviewing my notes, I realized that every difference I noted related back to the 10% change in FOV and/or Mag - not the optics themselves, which are both excellent.

CONTRAST: M31/32/110 is a beautiful sight in either EP. I used the outer reaches of M31 and shape & orientation of M110 to test contrast, and after much swapping back and forth decided I could see no difference. Likewise, on a last look at the Veil (only brighter half visible w/ Orion UltraBlock), I could detect no difference.

COLOR: For bright objects, I waited until after 11pm to use Jupiter and Sirius. When centered in the field of either EP, Jupiter had a sharp limb with bands visible and Sirius was a dense white ball. However, when either object was moved to the edge of the field in any direction, they produced inward magenta fringing. This effect was identical in the 22Pan and 24Pan, suggesting that it may be coming from the scope itself.

10% FOV DIFF: In my 101 I can't quite fit all 3 stars of Orion's belt into the FOV of the 22Pan, but I can comfortably with the 24Pan. When focused on the center star Alnilam, both outer stars remain focused, and the wide double Mintaka is a sharp split just inside the field stop. Similarly, with the Double Cluster at the edge of the FOV, the huge Stock 2 cluster doesn't quite fit in the 22Pan, but does in the 24Pan. The stars are pinpoint throughout the field - beautiful.

10% MAG DIFF: No one is going to use these EP's to split tight doubles, but I tried the lovely 10" double Almach anyway. Here, the 22Pan was marginally better at showing a white protrusion off the orange globe.

So I would definitely give the 24Pan the edge, but for factors other than image quality. I have to wonder if the 24Pan would even exist if Meade had not one-upped TV with their 24.5 SWA ;-)

Clear Skies, Milt

January 25, 2003 01:41 PM Forum: Astro Binoculars

Minimum Exit Pupil for Eye Alignment

Posted By Milton Wilcox

Here is a topic that I have not seen discussed since I have been on the forum. I wish I could take credit for thinking of it, but it was actually Mr. Alan Adler, who has authored many relevant binocular articles.

Anyone who has looked through a 3"-4" refractor at planetary magnifications will know that it sometimes takes a moment to "find" the exit pupil with your eye. The trick is usually to find the image from a distance and try keep your eye centered as you move to the eyepiece.

If this is a problem for one eye, Mr. Adler points out that it is hell to do simultaneously with both eyes. Not only that, but if only one eye is receiving light, the brain won't care because there is nothing to process on the blacked out side. So you might not even know that you were only using half of your binocular unless you closed one eye at a time to check.

For the vast majority of binoculars discussed on this forum, this is a non-issue because the exit pupils (Aperture divided by magnification) are typically several millimeters. But when you get into the interchangeable EP binos that I have been considering, I believe this could put an upper limit on usable magnification.

Just to talk numbers, my Canon 18x50's have a 2.8mm exit pupil and are NO problem. A Vixen 125mm zoom at 75x would drop to 1.7mm. Still easily usable? At one point Markus talked about taking Kowa Highlander's to 150x, which would drop the exit pupil to only 0.5mm! I suspect that this power on this bino would not be easily used, even if the collimation was perfect.

I would love to hear from anyone who owns, or has looked through binoculars with small exit pupils. Have you ever tried closing each eye in turn to see if the image disappears?

Still Thinking, Milt

January 30, 2003 12:32 PM Forum: Astro Binoculars

Another Advantage of Binos?

Posted By Milton Wilcox

Hello All,

Another reason to like binos for astronomy occurred to me in the wee hours this morning: It seems to me that all other things being equal, binos should show less color than single objective spotters or other refractors. My reasoning is that when the light gathering gets split between two objectives totalling the same area as one, the lenses don't have to be as fast to produce the same FOV.

Take 16x70's, for example, which have the same light gathering area as a single 100mm objective. Let's say their focal length is 300mm (I'm guesstimating since the f.l. is seldom given for fixed-mag binoculars). Dividing 300 by 70 yields f/4.3, already a fast lens. Now try to maintain the same focal length with a single 100mm objective, and you would need an f/3 lens! More bending equals more color, right? Or am I missing something here?

Thinking too much,
Milt

February 9, 2003 02:26 PM Forum: Astro Binoculars

My Decision and Thank You

Posted By Milton Wilcox

Hello All,

I recently ordered the Hutech/Astromeccanica Borg 100ED binoscope. I wish to thank Markus Ludes, Erik Lin, David Minnick, George Page, Ed Zarenski, Daryl Crowley, Mike Swaim, Larry Patriarca, and Davide Del Vento for your many insights during my 6 months of research. Davide, I'm sure, will be particularly impressed with my choice .

In the end I felt that this approach would provide the best balance of parameters that were important to me in an astronomical binocular. Since I already own one 24mm Panoptic, that will be my first EP pair, yielding 26.5x & 2.5deg.

I am assuming that this forum is meant to include binoscopes as well as binoculars, so I can pass along any surprises on this product, either good or bad... My mount and all eyepieces will be purchased from Astromart sponsors.

When you see the clouds gather over Arizona, you will know it's arrived :-)

Thanks again and Clear Skies,
Milt

February 10, 2003 10:48 AM Forum: Astro Binoculars

Vintage Japanese Binoculars

Posted By Milton Wilcox

Hello All,

While researching my late father-in-law's 40yr. old Japanese 7x50's, I came across a couple of websites that may be of interest to this forum. The first one is
http://home.europa.com/~telscope/jbcode.txt
which describes the Japanese Manufacturer's Code for optical products started in 1959. A list is given that allows you to decode the manufacturer based on numbers stamped in the frame. In my case, I found that these 'Tower' binoculars were actually manufactured by Ofuna, who made Japanese military binoculars for WWII.

The second site is
http://home.europa.com/~telscope/JpnSurvy.txt
which keeps track of data from vintage Japanese binoculars, with a form that you can use to add your binos to the anonymous database.

Old Japanese binoculars should not be overlooked for astronomy. These Ofuna's are very well made and still work well. Although only single-coated, they show little color due to the low magnification. At 7.1 degrees (about 80% usable), they provide a wider FOV than anything else I own.

Gotta quit collecting,
Milt

February 27, 2003 11:25 AM Forum: Astro Binoculars

Prof. Zarenski Writes the "Book" on Binos

Posted By Milton Wilcox

Hi Ed,

I have just finished reading your 'Comprehensive Comparison' report on CloudyNights and congratulate you on a job well done. The strength of your article extends far beyond the bino comparison, providing the best description of methodology I have seen. Before anyone buys another binocular of any size or type for astronomy, they should go to http://www.cloudynights.com/breviews/4way-2.htm and read your report!

IMO, the most significant aspect is that you confirmed Mr. Adler's performance index with quantitative measurements. I don't know how many threads I have read on this subject, but the arguments were always qualitative "I feel this way" or "I believe that." You have hopefully laid the matter to rest with definitive star counts. But you didn't stop there; your (-)10%, 0, (+)10% corrections for coating and baffle quality is a worthwhile improvement that helps to integrate Nikons, Fujinons, Kowas and Takahashis into the mix. Bravo.

Your point is well taken that magnification is so low in binos that the limiting magnitude and maximum resolution abilities of the objective lens cannot be reached. Consider this: if you used the 50x per inch of aperture rule, you would end up with 0.5mm exit pupils. Not much chance of simultaneously aligning both eyes to those!

In your eye relief discussions, the eyecup function really caught my eye . The more I have used my Canon IS', the more aggravating the 48mm OD eyecups have become because they rub the bridge of my nose. I much prefer the smaller diameter eyecups of my telescope EP's.

There is one minor caveat that could be placed on your focal ratio calculation: I think it only works if you have a single objective system like a closely spaced doublet. An example of a binocular with a negative (diverging) lens buried back in the tube is the Vixen BT80. If you calculate based on the light path length, it should be an f/5.5, but is actually an f/11. My TV101 scope has a second positive (converging) doublet, has the tube length of an f/8.5, but is really an f/5.4. As far as I know, your calculation should work fine for all fixed-mag binos.

I liked your common sense approach to evaluating coatings. Also the clear explanation of the difference between field sharpness and flatness, a distinction that I had missed! The use of tight (for binos) doubles to check edge sharpness is great, and your TFOV chart with various star spacings will come in very handy.

We'll have to start calling you professor!

Clear skies, Milt

March 4, 2003 08:59 AM Forum: Astro Binoculars

Kenny's Moon View

Posted By Milton Wilcox

Hi Kenny,

Just had to comment. A couple of years ago I did an impromptu survey with family and neighbors about what their favorite moon view was through my scope. They chose my 1 deg. Nagler view! I agree; there's something magic about seeing the whole limb surrounded by black.

Now this is the view I always show at star parties - hope to duplicate it soon in my binoscope.

Clear lunar views, Milt