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APM 100ED v.s. Kowa Highlander

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#51 APM M.Ludes

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Posted 03 May 2011 - 10:15 AM

Hi Rich

I used a Nagler 4.8 mm Type and maschine off the 1.25" barrel front the filter thread, height, that was enough to reach focuse with it.

what wonders me partly. Kowa use the same glas for here spotting scope eyepieces which housing seems to me more expensive then the bino eyepiece housing, but the spotting scope eyepieces cost only half. Maybe due production volume ????

Tracking a Kowa with such high power as my Naglers did, is no fun anymore. I enjoy the kowa power up to 50 times and for me its enough.

The problem I see with Kowa is that you cannot screw in 1.25" filters , therefore a US Filter company polished and coated me full size 90 mm UHC and O-III Filters

1 Filterset ( 2 pc Filters) diameter 90 mm with your O-III coating, 1/4 wave, 12 nm wide each US $ 1,175 and the set UHC Filters was $ 1,250 , but this was in the year 2005.
I cannot name the company, by TOS, but if somebody is interested to order such filters at that company, i can give you the infos offline

#52 Rich V.

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Posted 03 May 2011 - 11:13 AM

Thanks for the info, Markus.

I like your "work-around" for the use of UHC and OIII filters; unfortunately, custom-made 90mm filters are a bit rich for most of us, I'm afraid. You are fortunate to be in the business!

Luckily, I found I can fit standard 1-1/4" filters onto the 1.3" Miya eyepiece barrels with an easy modification and there is enough room between the rear prism window and the filter to allow focus.

I think that high magnification in most BTs enters into the area of diminishing returns at moderate powers. I enjoy 71x in my Miya Saturns but don't understand why Miya produced 150x/115x (5mm) eyepieces for their Saturn series. Rarely are conditions good enough here to use such a magnification and the limits of CA and SA are quite apparent even if they are. I think 100x would be pushing the limits of resolution with the Saturn IIIs; their optics are definitely not up to the level of the Kowas. There are instruments much better for use at 100x or greater than a BT!

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#53 Tamiji Homma

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Posted 03 May 2011 - 11:55 PM

It will be interesting to see if Tammy finds that the premium optics of the Kowa compensates for its smaller aperture compared to the APM in lower magnification views. It might since the Kowa should concentrate more light to a smaller spot size.



I did 1.5 hour side-by-side comparison, just to spot Saturn 6 moons. Well, I should have used the same power but I didn't.

I was able to spot 6 moons with both instruments. I had better chance to spot them with APM 100ED at 71x (Nikon NAV SW 7mm) than Kowa Highlander at 50x (Kowa 9mm). Saturn looked sharper with Kowa, though due to lack of CA. Seeing was about average, Enceladus and Dione were visible momentarily when seeing improved, no more than a few seconds using averted vision.

Next time I'll try at the same power using XW 10 on APM 100ED.

Tammy

#54 BobinKy

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Posted 04 May 2011 - 08:08 AM

Tamiji...

I think I have seen photos and posts of your Takahashi scope(s) with binoviewers. How does the Kowa Highlander compare?

#55 Tamiji Homma

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Posted 04 May 2011 - 09:31 AM

Tamiji...

I think I have seen photos and posts of your Takahashi scope(s) with binoviewers. How does the Kowa Highlander compare?


Hi Bob,

I think that TSA102 gives better view than Kowa at higher power. So far I can go up to 50x with Kowa. I am looking for shorter focal length eyepiece option to reach around 100x. Yesterday, I found that Siebert Ultra Series 28mm almost came to focus with Kowa. I emailed to Harry@Siebert to see if he can make custom eyepiece (shorter nosepiece to bring focal plane closer to OTA) with his new Triple S, Super Star Splitter.

I'll do comparison Tak with Kowa 21mm eyepiece on MarkV (yielding 48.6x) against Kowa Highlander with Kowa 9mm (yielding 50x) tonight. I'll let you know how it goes.

Tammy

#56 Tamiji Homma

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Posted 05 May 2011 - 12:27 AM

Hi Bob,

Seeing was above average, quite good tonight but transparency wasn't that great.

Judging from Saturn image, TSA102S/MarkV/Pano 19 (51.2x, 1.25 degree TFOV, 1.99mm exit pupil) shows sharper and more contrast image than Kowa (50x, 1.34 degree, 1.64mm).

Kowa had brighter Image than TSA102S. I felt Kowa was easier to spot 6 moons but pretty close.

Oh I forgot to mention that I used Baader Amici Prism Diagonal with TSA102S.

Waiting for Saturn:
Posted Image

Tammy

#57 Jawaid I. Abbasi

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Posted 05 May 2011 - 01:50 AM

Tammy,
Is not because of exit pupil(1.99) in your TSA?

#58 Mark9473

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Posted 05 May 2011 - 02:03 AM

Jawaid, don't forget that for the same size exit pupil, the image through binoviewers is only half as bright as in the binoculars.

Tammy, I have one of Harry Siebert's SSS eyepieces and the field lens is immediately behind the filter thread, at least in my 8.4mm EP. That would mean he can only take off 2 mm or so of the nosepiece length.

#59 BobinKy

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Posted 05 May 2011 - 07:01 AM

Tammy...

Thanks for the comparison between your Tak with binoviewers and Kowa Highlander. This is very helpful.

You have some fantastic equipment. Can you describe the tripod, mount, and push-to electronics of both setups (left and right).

Thank you.

#60 Tamiji Homma

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Posted 05 May 2011 - 08:34 AM

Thanks, Mark for the information.

Harry hasn't responded to my query yet. I guess I should give him a call :)
I hope focal plane is close to field lens. Kowa eyepiece holder depth is only 18mm so length of nosepiece is also important factor to find eyepiece to reach focus.

Tammy

#61 Tamiji Homma

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Posted 05 May 2011 - 09:06 AM

Can you describe the tripod, mount, and push-to electronics of both setups (left and right).



Hi Bob,

On left, the tripod is Berlebach Planet. The mount base is Losmandy G11 mount compatible. The alt/az mount is Kokusai Kohki T-REX mount, bottom of T-REX is Discmounts G11 adapter for DM-6 mount. Single center 3/8" screw is used to attach T-REX and the G11 adapter. It has slow-motion control. It works very well. You can track 40+lb 6" f/8 at 300x on T-REX.

The T-REX has built-in alt/az encoder. You can connect computer like SkyCommander.
Posted Image

You can read about T-REX here.
http://www.kkohki.co...T-REXmount.html
http://www.cloudynig...hp?item_id=2596

On right, the mount is HalfHitch alt/az mount. It is the smoothest alt/az mount that I've ever used. It is sensitive to unbalanced scope but once you achieve perfect two axis balance, it is amazingly smooth and accurate. Scope weight almost disappears. I think it is the best alt/az for 100mm-ish binoculars. It also has alt/az encoder for computer.

The tripod is one came with William Optics EzMount. I am replacing the tripod with lighter and sturdier carbon fiber tripod soon.

Tammy

#62 Mark9473

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Posted 05 May 2011 - 01:15 PM

I hope focal plane is close to field lens.

There's a good probability for that, as with the SSS I need significantly more back-focus.

#63 Rich V.

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Posted 05 May 2011 - 01:52 PM

Tammy, hopefully when you get a chance, we can hear more about direct side-by-side comparisons between the Kowa and the APM on a variety of objects.

This would be more of an apples-to-apples comparison and I'm sure many of us here would love to read more about it. I'm looking forward to a "finesse" vs. "brute force" binocular evaluation particularly on DSOs.

Thanks,

Rich V

#64 rodb

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Posted 05 May 2011 - 03:52 PM

Tammy, hopefully when you get a chance, we can hear more about direct side-by-side comparisons between the Kowa and the APM on a variety of objects.

This would be more of an apples-to-apples comparison and I'm sure many of us here would love to read more about it. I'm looking forward to a "finesse" vs. "brute force" binocular evaluation particularly on DSOs.

Thanks,

Rich V


Yes, indeed.

To go further, if you're willing to play along here on this highly subjective exercise, I'm wondering how many of you would spend the considerably extra $$ to get the Kowa, assuming of course that the purchase wouldn't hurt you or your family. (Or any similarly deluxe items as compared with quite serviceable but lesser equipment.)

(On a personal note: I'm retired, having worked 39 years in my profession, with a good pension, I take care of my adult son who only has a part-time job (since the recession broke), bought him a car and making the payments and giving him several hundred in cash/month. And my "good" days are "numbered." :grin: Money-wise I can afford it, i.e., it wouldn't impede my "life-style," so I shouldn't feel guilty about making this purchase, yet psychologically/emotionally it still would be a major stretch. Hard to change old habits. Following my namesake: R.O.D. Responsibilities, Obligations, Duties. ;))

Just how much better performance might this fluorite "APO" be in comparison with the APM or other 100mm BTs? Tammy, hopefully, will provide some viewing experiences.

Now I fully understand that as you go way upscale in equipment expenditures, you may only be getting an equivalently smaller amount in performance, i.e., not a bang-for-the-buck transaction. And only you can decide on this formulation.

So, given the above proviso of personal affordability, are you willing to spend that significantly extra amount to get that extra bit of performance satisfaction in an instrument like the Kowa - that AH! moment that you can't get in any other equipment?

Thanks for playing along, and I'd be most interested in your thoughts.

I may not have stated my case very elegantly, but I hope you understand what I'm trying to get at.

Regards, Rod

#65 GamesForOne

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Posted 05 May 2011 - 04:36 PM

So, given the above proviso of personal affordability, are you willing to spend that significantly extra amount to get that extra bit of performance satisfaction in an instrument like the Kowa - that AH! moment that you can't get in any other equipment?


If money is absolutely no concern, sure.

I keep hoping that APM can produce APO binoculars in the 100mm range for perhaps $2000 or less with all the flexibility in eyepiece choice as currently is the case with the ED100. That would be something I perhaps could afford and would consider, but I am pretty happy with the ED100 for now.

But $5000? No. It would be smarter to buy the ED100 and an APO (for higher mag views) in my opinion.

If money is no object heck I'd rather have the 141mm Miya binos that were available in the past.

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#66 rodb

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Posted 05 May 2011 - 05:52 PM


So, given the above proviso of personal affordability, are you willing to spend that significantly extra amount to get that extra bit of performance satisfaction in an instrument like the Kowa - that AH! moment that you can't get in any other equipment?


If money is absolutely no concern, sure.

But $5000? No.
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Michael Mc


Thanks, Michael, I'm up against the same personal limit. Too bad, I imagine the Kowa would be terrific.

But would you know how good the Kowa really is, given the subjective nature of this query?

And while I'm at it, I'm still not firm on the 100mm BT vs. the 70MM BT (Garrett). I read that people think this 70mm is sharper and with better contrast as Garrett's 100mm version. Is this the consensus?

Rod

#67 EdZ

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Posted 05 May 2011 - 06:09 PM

I read that people think this 70mm is sharper and with better contrast as Garrett's 100mm version. Is this the consensus?



This is one of those things that makes no sense. Given no serious optical aberrations, no optical misaligmnet and no defective coatings, when comparing two optics, contrast transfer is a function of aperture. So a larger aperture will always show better contrast.

The only thing I can think of that would make people "think" they see better contrast in a 70mm vs a 100mm is that it would have a smaller exit pupil at same magnification. That's not really better contrast.

If you campared both at 20 power, 20x70 and 20x100, you would have 3.5mm exit pupils and 5mm exit pupils. The 70mm would show a darker background, but probably not any more or less objects.

If you were to compare the 70mm and the 100mm at a 2.5mm exit pupil, 28x70 and 40x100, the image brightness in both will be equal and you are going to see much much fainter objects in the 100mm against the same sky background.

edz

#68 rodb

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Posted 05 May 2011 - 06:54 PM

Thanks, EDZ,
Very helpful. This might just help nudge me off the razor sharp precipice of analysis/paralysis.

Regards, Rod

#69 BobinKy

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Posted 05 May 2011 - 08:19 PM

Tammy...

Thank you for taking the time to share information about the tripod, mount, accessories, and push-to electronics of both setups. Your knowledge of premium optics and equipment is excellent. I find it very helpful to know what is required to put together a premium setup.

I certainly appreciate the time you have invested in selecting and acquiring the tripods, mounts, accessories, and push-to electronics in the setups. For my own small part, I have invested more than 80 hours in researching a stable setup for my Celestron C6 6-inch sct. Optics are one thing--tripods, mounts, and accessories are another. And to have knowledge of all four, as you most certainly do, is a great thing.

I always enjoy reading your posts. Thank you again.

#70 Tamiji Homma

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Posted 05 May 2011 - 11:24 PM

This would be more of an apples-to-apples comparison and I'm sure many of us here would love to read more about it. I'm looking forward to a "finesse" vs. "brute force" binocular evaluation particularly on DSOs.


Yes, I'll report when I have good DSO observing sessions. My expectation (guess) is that Kowa Highlander gives prettier image for objects that are not near visibility threshold (brightness) and APM 100ED will outperform Kowa when there is not enough light for Kowa. I mean "aperture" win case.

I don't think optical quality alone can overcome 48% more light gathering power of APM 100ED over Kowa.

I also use the binoculars for terrestrial viewing. There is no competition for daytime viewing. Kowa wins big daytime.

By the way, I just came back from short session. I didn't use binoculars tonight. I observed Saturn with TMB 80SS f/6.3. Seeing is superb tonight. I was at 201x (2x Zeiss Barlow + Tak LE 5), image was crisp, CD was not just darken blip on ring but I could see CD ring as line and two creamy bands on Saturn. I don't think I have seen this much with 80mm scope before.

I'll go back to observation :)

Tammy

#71 Tamiji Homma

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Posted 05 May 2011 - 11:51 PM

If money is no object heck I'd rather have the 141mm Miya binos that were available in the past.


Hi Michael,

If money is no object, you would want to move to high elevation dark site instead :)

I wonder if CNer BlueRidge is up to with BR-141?

Tammy

#72 GamesForOne

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Posted 06 May 2011 - 07:38 AM

But would you know how good the Kowa really is, given the subjective nature of this query?


FWIW, I have a 105mm triplet APO with Denk II binoviewer. I know how a good refractor image appears. I do love it.

The APM puts up a respectable image in the 25x - 50x range in my opinion, for the price, and they are considerably easier to setup with more portability.

That said, I do see the APM's shortcomings (CA) at night with increasing magnification and I am sure the Kowa's dust the APM's daylight performance. However, you can also put 82mm masks on the APM's objectives and probably get closer.

It depends on what you want to do with the binos and how much disposable income you have. Just to give you more to think about, you can also consider the Miya 100mm as well but note these do not have APO objectives nor do they accept standard 1.25" EP's.

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Michael Mc

#73 GamesForOne

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Posted 06 May 2011 - 07:45 AM

Hi Michael,

If money is no object, you would want to move to high elevation dark site instead :)


Yeah, yeah, that's the ticket. Let's see:

- Comfortable house and observatory at Arizona Sky Village or somewhere near Cloudcroft in NM (or if money is really no object perhaps the Canary Islands?).

- Personal jet ready to go at moments notice to get me there.

- Nice 20"+ RC and astrocamera setup, fully automated so I can take pictures from anywhere over the Net.

- 30"+ dob in a roll-off at the site.

- 6"+ APO for planetary observing.

- Become a philanthropist so everyone would love me and I would get to talk at TED.

That's a start at least, but I would still want the binos too.

I wonder if CNer BlueRidge is up to with BR-141?


Did someone in NC buy them? I'll have to look that up and find out when and where. :step: I am only about two hours from prime NC Blue Ridge locations.

---
Michael Mc

#74 rodb

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Posted 06 May 2011 - 08:08 AM

[quote name="GamesForOne"][quote]

The APM puts up a respectable image in the 25x - 50x range in my opinion, for the price, and they are considerably easier to setup with more portability.

That said, I do see the APM's shortcomings (CA) at night with increasing magnification and I am sure the Kowa's dust the APM's daylight performance.

It depends on what you want to do with the binos and how much disposable income you have. Just to give you more to think about, you can also consider the Miya 100mm as well but note these do not have APO objectives nor do they accept standard 1.25" EP's.

---

Michael Mc [/quote]

Michael, thanks. Could you be a bit more specific, if possible, in defining "respectable," as in "The APM puts up a respectable image in the 25x-50x range (in your opinion, for the price)...

Also I'm curious of your opinion of the value of the Miya 100mm BT, given the price of $3150, which includes two sets of EPs and a case, considering it is not an APO and doesn't accept standard 1.25" EPs. They are relatively light (13#) and cosmetically quite beautiful. Is the additional price reflective more of currency exchange rates than of viewing quality, as compared with the APM (or GBT, for that matter)?

I'm trying, in my own way, to sort out all these BT options and to see whether paying more is justified, especially for my light polluted city balcony.

Regards, Rod

#75 BobinKy

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Posted 06 May 2011 - 08:15 AM

Ah, but your dreams are so small. Why not build your own observatory with two or three domes. Surely, you will want a 120" reflector to rival the one at Lick Observatory, and a 6" refractor could easily become 12" or more. And then, you will also want to employ several astronomers to pursue observing programs. At least 14 astronomers, so two can share the scopes each night of the week.

Dreams - yiruma

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