revans
Carpal Tunnel
Reged: 09/26/05
Posts: 1514
Loc: Fitchburg, MA
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I see that Leica and Zeiss make fluorite lens binoculars but I'm not sure if these are real fluorite or some sort of FPL low dispersion glass. The most interesting to me was the Zeiss Victory which is 8 x 56 mm. I assume that these high end and very expensive binoculars are intended to be apochromatic... but from what I know about telescopes it is impossible to make an apochromat with a real low f-ratio.... and what could have a lower F ratio than binoculars?
Is there any advantage to fluorite lens or ED lens binoculars for astronomic use? Is it worth the price premium?
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Rick Evans
http://www.freewebs.com/revans_01420/
"The universe is there for us to see, but it cannot be understood without learning its language -- mathematics." Galileo Galilei
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Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 908
Loc: By Edinburgh , Scotland
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Im new to Binos not Refractors,but from my brief experience i would say that CaF2 objectives are worth it,im not sure that the Leica or Zeiss options (as much as i "Worship" these Manus) are CaF2,but be careful as once you try fluorites there is no going back,im already thinking about larger objectives 
Brian
PS i would love to hear about other CaF2 binos apart from the obvious Highlanders/Taks
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" Gentlemen only ever use Refractors "
Edited by Solar B (10/18/09 06:35 PM)
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jkevn
sage
Reged: 03/02/06
Posts: 211
Loc: Tucson, Arizona
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Except for the moon, Jupiter, Venus, possibly Mars at opposition, and very bright stars, chromatic aberration isn't very noticeable for me. It would seem that with apochromatic 3-element objectives or ED glass, more light would be concentrated from stellar point sources, so this might extend the limiting magnitude a little, but someone would have to test this to see by how much, if at all. I wouldn't think that it would make much of a difference for diffuse objects like nebula.
If you really like views of the moon without color fringing on the moon's edge, then maybe it would be worth it.
Chromatic aberration, for me, is far more distracting in daytime viewing (possibly because I know it is there and I look for it automatically). I can see how this would be important for birding.
Since I had cataract surgery in both eyes, I notice it more at night looking at the moon and bright stars with binoculars and through my 12" scope.
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GaryS
super member
Reged: 10/30/06
Posts: 191
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Quote:
Is there any advantage to fluorite lens or ED lens binoculars for astronomic use? Is it worth the price premium?
I carefully compared cosmetically identical 10x50s by Orion and William Optics for a S&T Test Report once. The W.O. binos claimed to use ED glass, the Orions did not. In performance, they appeared to be identical. That's not a definitive answer to your question, but it is a direct comparison with a minimum number of variables in the mix.
That said, I'd be surprised to discover any colour correction differences at binocular magnifications that could be traced to the objective lenses. Other factors (overall optical quality, mechanical build) are likely to be more important.
Regards,
Gary
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Sky & Telescope Contributing Editor
SkyNews Columnist & Blogger
www.GarySeronik.com
A place for stargazing enthusiasts.
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charen
Pooh-Bah
Reged: 05/28/05
Posts: 1082
Loc: New Zealand
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"The W.O. binos claimed to use ED glass, the Orions did not. In performance, they appeared to be identical"
Previous reviews on these W.O. binos appear to indicate that the ED glass is in the oculars not in the objectives ?
I have not been able to verify this.
This ED glass positioning would not have such a significant effect in image quality as if they were in the objectives.
I do have a excellent Minox 10x58 ED. The image - contrast, brightness and resolution is very good - however CA is still mildly discernable. As Gary says are other multible factors do go into making a superior bino. I guess ED glass helps that process.
Chris
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35 binos.
80mm Cat.
WO66ED
SV NH 80mm / EQ3
Meade 8in.LX90
Skywatcher Equinox ED120 / Goto HEQ5.
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GaryS
super member
Reged: 10/30/06
Posts: 191
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Quote:
Previous reviews on these W.O. binos appear to indicate that the ED glass is in the oculars not in the objectives ?
I have not been able to verify this.
From the description of the 10x50s on the William Optics web site:
"Extra-low dispersion glass objectives for an exceptional color correction (almost no false colour)." (Emphasis mine.)
Never heard the story about using ED glass in the eyepiece before.
Gary
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Sky & Telescope Contributing Editor
SkyNews Columnist & Blogger
www.GarySeronik.com
A place for stargazing enthusiasts.
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charen
Pooh-Bah
Reged: 05/28/05
Posts: 1082
Loc: New Zealand
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Hi there was a thread about a year or so ago regarding this subject re. the ED glass position - which I cannot find now. Sorry for the confusion.
Chris
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35 binos.
80mm Cat.
WO66ED
SV NH 80mm / EQ3
Meade 8in.LX90
Skywatcher Equinox ED120 / Goto HEQ5.
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John F
sage
Reged: 02/16/04
Posts: 383
Loc: Washington State
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I certainly feel that the 22x60 Takahashi Astronomers were well worth the $1050 I paid for them (new) back in 2005. They're outstanding binoculars in general and do provide false color-free images of the moon.
As to whether I think the 32x82 Kowa Highlander Prominar model (i.e., the fluorite one) is worth the extra $1400 it costs over the non-fluorite model I can't say. I've never seen a review of those two models and how they compare to one another. Obviously, for lunar and planetary viewing the Prominar model would have an advantage. However, for deep sky observing (which is what binocular are primarily used for) I'm not sure so sure that they Prominars are worth their extra $1400 cost. Are there any 32x82 Kowa Highlander users (i.e., of the non-Prominar model) out there who can speak for how well they think they perform in general as well as (in particular) they perform for deep sky observing?
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BINOCULARS
Nikon 7x50 Prostar
Swarovski 8.5x42 EL
Nikon 10x70 Astroluxe
Zeiss 15x60 B/GAT
Takahashi 22x60 Astronomer
SCOPES
Questar 3.5-Inch
Tele Vue NP-127 with TV Bino Vue
EYEPIECES
Deep Sky: 31Nagler, 17-13-10-8-6 Ethos
Lunar & Planetary: 16-10-6-4 ZAO-II
Binoviewing: 24Pan,16Nagler, 10ZOA-II,7.5Taks
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nocturne
newbie
Reged: 11/08/08
Posts: 4
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Quote:
I see that Leica and Zeiss make fluorite lens binoculars but I'm not sure if these are real fluorite or some sort of FPL low dispersion glass.
It's not flourite (CaF2) but fluoride-doted glass.
How good the effect is depends on the total configuration of the optical system it seems.
Most certainly, not all hyped "ED"s are equal.
There has been a very enlightening explanation of the background here:
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3193178/page/0/view/collapsed/sb/5/o/all/fpart/1
some additional discussion here:
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3016684/page/0/view/collapsed/sb/5/o/all/fpart/1
T
Edited by nocturne (10/20/09 05:11 AM)
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edwincjones
Postmaster
Reged: 04/10/04
Posts: 5657
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I have the Miyauchi 100mm fluorite binoculars, and the dark, crisp, constrast is very pleasing; and better optics than my Fuji 25x150MTs.
(but I still have color and APO is ?)
Other have pointed out that the fluorite is less important in lower magifications.
edj
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n w arkansas
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Luigi
Post Laureate
Reged: 07/03/07
Posts: 4933
Loc: MA
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In my experience, high quality ED bins produce very crisp, sharp, fine detail on objects like bird feathers, flowers and leaves, spider webs, surfaces of rock, etc.. The low CA preserves contrast on these fine details. For me, the benefits are less significant for bino astro observing.
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17.5" f/5 Dob. IM-715 MCT. 120ED. Lunt 60mm Ha.
Zeiss, Leica, Fujinon, Nikon, Pentax, Bushnell bins
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Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 908
Loc: By Edinburgh , Scotland
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Quote:
I certainly feel that the 22x60 Takahashi Astronomers were well worth the $1050 I paid for them (new) back in 2005. They're outstanding binoculars in general and do provide false color-free images of the moon.
Well that would mean that i could have bought a new pair
a few years ago Stateside for about £550,you would be lucky to get a secondhand pair over here now for less than £800.
Brian
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" Gentlemen only ever use Refractors "
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milt
professor emeritus
Reged: 09/13/04
Posts: 551
Loc: Arizona
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Quote:
For me, the benefits are less significant for bino astro observing.
I would agree for low magnifications. However at higher mag's, the ability to bring as much of the visual bandwidth as possible to the same focus determines how many faint stars can be resolved in clusters - which are a popular target for me, anyway. This requires two things: ED glass (not necessarily fluorite) to bring the blue and red ends of the spectrum to the same focus as green, and good spherical correction to bring rays entering all parts of the objective to the same focus. You pay big bucks for binoculars that can do this, but they do have better stellar limiting magnitudes. As usual, the last 10% always seems to cost 10x as much...
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Clear skies, Milt
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 14713
Loc: Cumberland, R I , USA42N71.4W
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Quote:
at higher mag's, the ability to bring as much of the visual bandwidth as possible to the same focus determines how many faint stars can be resolved in clusters - which are a popular target for me, anyway. This requires two things: ED glass (not necessarily fluorite) to bring the blue and red ends of the spectrum to the same focus as green, and good spherical correction to bring rays entering all parts of the objective to the same focus. You pay big bucks for binoculars that can do this, but they do have better stellar limiting magnitudes. As usual, the last 10% always seems to cost 10x as much...
I commented on this in my recent tests with the Tak 22x60 vs the WO22x70 and GO22x85. A nice group to test since they are all the same power. Although the GO has significantly greater aperture, both the WO and the Tak have significantly smaller spot size. They can see just about equally deep in magnitude and can see significanly better close doubles.
The spot size in the WO is smaller than the GO, But to see the difference between the Tak spot size and the GO spot size is remarkable. However, it's been mentioned, that is not all just due to CA correction in ED glass, or in the case of the Taks, true flourite. Much of it has to do with the correction of the lenses, for instance the degree of spherical aberration. The GO spot size isn't twice as large as the Tak simply due to color correction.
Most people still don't get it, but Milt made a very significant point about color correction at low powers, a point being overlooked by a multitude of people. See the links above to ED in binoculars. Most of what you read from people about color correction in low power binoculars being attributable to ED glass is ...... well, go read that other thread.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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I'd rather have a well corrected achromat than a poorly corrected ED/Fluorite doublet.
It doesn't hurt to have a slower focal length ratio either.
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
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BillC
on a new path
Reged: 06/04/04
Posts: 2237
Loc: Washington, USA
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"I'd rather have a well corrected achromat than a poorly corrected ED/Fluorite doublet.
Seems PCAD doesn't fall for the buzzword games!!! Good man!!!
Cheers,
Bill
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William J. Cook, Chief Opticalman, USNR-Ret.
Founding Editor, Amateur Telescope Making Journal
20-year vet. of Captain's Nautical Supplies, Optics Dept. Mgr.
Optics Machanic, WG11-3306, Ft. Lewis, Tacoma,WA
Yata, Yata, Yata . . .
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Swedpat
Pooh-Bah
Reged: 02/18/05
Posts: 1120
Loc: Boden, Sweden, Scandinavia
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Personally I doubt it's worth, when talking about "normal" handhold magnifications. I usually never become aware of CA of binoculars. But I understand that this really is a matter of sensitivity, which can vary between different persons.
Regards, Patric
Off topic: I just noticed that BillC at the post before me had exactly twice the numbers of total posts than me. (2226 vs 1113) How big chance is that this shall happen at the same time and the posts beside each other...
Edited by Swedpat (10/21/09 12:24 PM)
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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With the Tak's, which I expect will be back in my hands soon, I believe the performance has more to do with the objectives being well corrected and well figured compared to standard binocular objectives. Their long f/6ish focal ratio helps a lot also.
The Tak's objectives are high quality telescope objectives which likely could be used at 120x or more. At these magnifications having APO performance makes a differance. At 22x, not so much.
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
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GaryHeath
super member
Reged: 08/13/09
Posts: 118
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Interesting thread ....
Other than the colored rings on bright objects, it appears that you need to be at a power then can appreciate the benefit of the fluorite/ED glass.
Then the next gate is you have to have eyes that can appreciate whatever additional benefit is attributed to the somewhat limited increase at typical binocular powers, which (in most practical bino observing) is in turn further limited to the amount of targets that can benefit from which in practical use basically gets back to the color halo reduction as the main benefit of the additional expense.
So ...... unless you are already looking at large hi power binos, and bright targets viewed by younger eyes than mine, it appears to be something that one might be better off using the dollar difference to go ahead and buy those larger binos .... but as achro's, and using the "saved" money to purchase better mounting for them ..... both at significantly less cost than "premium glass". binos.
For example ...... the difference between the Fuji 25X150 MT and ED is enough to buy the MT's 'and' a delivered StarChair 3000 ...... with some left over to also buy a really nice "make-up" gift for the wife, to be presented at a 5 star restaurant prior to an evening of dancing and romance!
That's what I did ......... 
And it was all paid for with my settling for only a hint of colored rings, and then on a only a 'few' of the brightest bright objects (that aren't the typical target for my binos) and the most remote possibility of more faint stars for my old eyes to try and see. As almost certainly ...... any increase in detail of diffuse objects (my normal targets for binos) brought on by all of the spectrum being in better focus would be so elusive that I probably couldn't see the difference in these targets ....... even in my younger eye'd days.
Also ........ I have a W.O. FluoroStar 110mm refractor and an AP155EDF.
Although the TEC objective in the W.O. 'is' the premium glass version of this scope, and there is no false color to bright objects, there 'is' a yellow/warm cast to the image when looking through it, that I don't see unless I do a 'side by side' with my AP155EDF.
The original AP binoviewers did a similar thing to the image, they added a blue/cool cast to it that wasn't seen unless I compared it to a set of TeleVue binoviewers during the same session.
So I would add to this conversation, that even though a given set of optics is in fact premium, there can be more to it than that.
And both brand name and type of glass used, is not a guarantee that you will get what you might think you are, from only the advertisements and spec's.
At the price increase for premium glassed binos, I would want to do a 'side by side' to verify I was truly getting what I was paying that extra money for.
Best regards,
Gary
Edited by GaryHeath (10/22/09 02:51 PM)
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milt
professor emeritus
Reged: 09/13/04
Posts: 551
Loc: Arizona
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Quote:
At the price increase for premium glassed binos, I would want to do a 'side by side' to verify I was truly getting what I was paying that extra money for.
Gary, yours was a thoughtful post that I'm sure most here will agree with.
In Peter's case, his premium binocular glass is actually long-proven Takahashi telescope fluorite objectives. And since you are the extremely lucky owner of an AP155EDF you might appreciate this story: A friend of mine who owns several A-P's also collects binoculars and is an occasional poster to this forum. The first night I set my Kowa 32x82 fluorite up next to his 155EDF he was so impressed that he ordered one for himself along with the optional 50x eyepieces!
So, yes, premium glassed binos can play with the big boys.
Milt
PS - The warmer coloration you saw in the WO110 relative to the AP155 may have been due to the dimmer image. I noticed the same effect when comparing my 130EDT to a larger TEC on Saturn. In this case the A-P being smaller had the warmer coloration.
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Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 908
Loc: By Edinburgh , Scotland
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Im thinking that due to the general faster nature of binos compared to refractors fluorite may be more beneficial,than say fpl53 over fluorite in slower refractors where the difference is less noticable.
But for me its not so much the colour correction the taks offer but their contrast and perhaps this may just be due to their baffles.
http://www.trutek-uk.com/takahashi/takbins.html
NB this is an Old out of date Ad
Brian
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" Gentlemen only ever use Refractors "
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 14713
Loc: Cumberland, R I , USA42N71.4W
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Quote:
But for me its not so much the colour correction the taks offer but their contrast and perhaps this may just be due to their baffles.
Premium contrast is achieved in instruments with better lenses. To improve contrast, the lens must be figured such that all the light in the image is concentrated into the smallest image circle. In that way, the concentrated light of the object does not have as large an image blur circle that tends to overlap with adjacent areas, and the result is sharp definition at the edges between light and dark areas, hence improving contrast. Therefore improved contrast would primarily be a function of a premium lens figure, or a reduction of aberrations in the lens, or a lack of spherical aberration, astigmatism, coma, chromatic aberration.
Proper baffles will prevent stray light from interfering with image, but for most viewing the objects we look at are much to faint to cause internal stray light bright enough to interfere with the image.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 908
Loc: By Edinburgh , Scotland
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Well thanks again for that concise information Edz
What i can say is that im going of refractors faster than i can say Jack Robinson,Binos are just so easy to use and i can have a pair outside on a mount in less than a minute 
Back on topic,if you consider the price of a couple of Tak Sky 90s then the Prominar Highlanders albeit 82s may well be worth it.
Brian
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" Gentlemen only ever use Refractors "
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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True, but still a chunk 'o change.
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
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milt
professor emeritus
Reged: 09/13/04
Posts: 551
Loc: Arizona
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Quote:
the general faster nature of binos compared to refractors fluorite may be more beneficial,than say fpl53 over fluorite in slower refractors
Brian, I am not an optical designer but from what I have gleaned from Roland Christen's posts over the years I believe this is a correct statement. Roland, being an imager, designs fast lenses with good correction into shorter wavelengths and has said that all other things being equal, fluorite offers an advantage over FPL53 to achieve this.
The other marginal advantage of CaF2 over FPL53 is that CaF2 has zero light scattering, which is why a green laser completely disappears when passing through it.
Quote:
Premium contrast is achieved in instruments with better lenses.
Very true, and one of the ways lenses can get better is when the optical designer has more degrees of freedom. The majority of binocular objectives are cemented doublets, which means that the inner radius of the first lens must exactly match the inner radius of the second lens it is cemented to.
Both the Takahashi and Kowa fluorite objectives are air-spaced doublets, meaning that these inner radii can be different as required to improve the correction - but now they also have to be coated. This is a more expensive objective to make both because of the figuring and the more involved cell required to keep the two lenses in precise alignment to each other and the optical axis.
Milt
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Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 908
Loc: By Edinburgh , Scotland
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Quote:
True, but still a chunk 'o change.
Aint it the truth Peter and i havn,t got that kinda spare change kicking about 
Hi Milt...well if Roland says something i believe it 
Yep i knew that green lasers are absorbed by Caf2,its one neat trick to try on objectives
I like Edz "premium contrast" comment,gonna have to get me some more of those devices .
Brian
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" Gentlemen only ever use Refractors "
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1250
Loc: Ottawa, Ontario, Canada
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Regarding the issue of contrast transfer. I think of it as being an issue divisible into two scales.
As EdZ has relayed, accuracy of figure determines how well image-forming light is delivered to the Airy disk. Poor optical figures cause 'spill' of light outside the Airy disk, resulting in one or more optical aberrations. This affects image contrast, but on necessarily small scales. Such objects as planetary detail and close binary stars are adversely impacted by this small-scale degradation of contrast.
On a much larger scale, contrast transfer is affected by scattered light. Sources of scatter include poor baffling, inefficient coatings and non-blackened lens/prism edges. This results in a veiling glare not very unlike a distractingly bright light in one's line of sight.
However, is it fair to state that at the low light levels encountered during astronomical observation this veiling glare will be of a too-low intensity to be significant? To be sure, the visual system's inherent and ever increasing 'noise' as image brightness decreases does put glare's contribution deeper into that noise. But it can't be discounted, for two reasons:
- The ratio of non-image glare to image-forming light remains constant at all times, irrespective of image surface brightness. If veiling glare in a daylight scene constitutes 5% of the mean surface brightness, so too will it at night.
- In faint object observation, where contrast is already necessarily *very* low and an object might be brighter than the sky by 5-10%, that veiling glare can assume somewhat more significant proportions than it would for a rather more contrasty daylight scene.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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milt
professor emeritus
Reged: 09/13/04
Posts: 551
Loc: Arizona
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Quote:
Yep i knew that green lasers are absorbed by Caf2,its one neat trick to try on objectives
Brian, I wouldn't have used the word "absorbed" (maybe a different definition on the other side of the pond)? It's more that the laser beam passes through without leaving a trace. Yes, it's a fun test - I have attached a picture of CaF2 crystal sandwiched between two glass lenses.
Milt
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1250
Loc: Ottawa, Ontario, Canada
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Milt,
If such a picture is presented for us rubes to assimilate, please explain what it is we are seeing. For example, is the gap separating the two bright line segments occupied by the CaF2 element? (And by extension, are the bright line segments themselves caused by scattering within the (simple) glass plates?) Are the bright spots terminating the line segments the air-glass and glass-CaF2 interfaces, where reflection would be greatest?
I'll assume the array of faint spots are largely if not completely immaterial.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 14713
Loc: Cumberland, R I , USA42N71.4W
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Correct on all counts.
It's hard to remember sometimes in these forums that issues/tests/discussions and even photos that document all the things we've found over the years, although still in residence and accessible here thru our links, did not have the participation of all members, nor have they been read or seen by everyone.
There is an older series of posts with photos showing the images of a green laser thru a variety of lenses.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 908
Loc: By Edinburgh , Scotland
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Hi Milt,Im guessing the lefthand laser image is the entry point and the righthand is exit,thanks for the image
Hi Glenn i don.t know who rubes are but then again i don,t know what grits are either and im needing dew shields 
Ive got a lot of catching up to do have to work my way through the Best of Binos sticky
Brian
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" Gentlemen only ever use Refractors "
Edited by Solar B (10/25/09 06:34 AM)
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milt
professor emeritus
Reged: 09/13/04
Posts: 551
Loc: Arizona
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Quote:
I'll assume the array of faint spots are largely if not completely immaterial.
Glenn, As Ed says the green laser test has been covered before but I believe you are the first to comment on the array of faint spots.  They appear to be fainter orthogonal versions of the main laser beam but the two detached spots could be reflections from farther down the tube. I will add that one of the "simple" glass lenses is BK7. I don't know what the other one is.
Here is a picture I just took of my 82mm Highlander objective. I had to hold the laser at a steep angle to capture the two lenses, which resulted in many more unwanted reflections that I removed for clarity. From left to right the brightest spot is the entrance point, then a visible line through the front glass lens, then spots for glass-to-air and air-to-CaF2 transitions, nothing visible in the CaF2 lens and finally a fourth spot at the CaF2-to-air exit.
I believe in the Takahashi 22x60 the CaF2 lens is in front of the glass lens, so the sequence would be reversed.
Milt
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Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 908
Loc: By Edinburgh , Scotland
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Tried the Taks on a "bright" Moon last night "Halloween" for the first time,no colour fringing at all that i could detect (sorry but i was looking for it)
To be honest a bit of colour would not have been a problem as i was delighted with the 3D view.
However i would say that they are Astro only binos.
Brian
PS the seller had stated in his advert that the belts on Jupiter could be easily viewed,im having trouble seeing them.
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" Gentlemen only ever use Refractors "
Edited by Solar B (11/01/09 01:14 PM)
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milt
professor emeritus
Reged: 09/13/04
Posts: 551
Loc: Arizona
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Quote:
Tried the Taks on a "bright" Moon last night "Halloween" for the first time,no colour fringing at all
Brian, did I miss something and you acquired a Tak 22x60? And couldn't you leave it mounted and point it at something terrestrial during the day...?
Milt
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mooreorless
Just worried
Reged: 07/05/05
Posts: 1821
Loc: Cornpropst Mills,Huntingdon,Pa
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I don't understand how the Tak 22x60 could not be a terrestrial binocular as well. I would think it would make an excellent lower power daytime binocular.
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Regards,Steve M
Edited by mooreorless (11/01/09 01:43 PM)
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Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 908
Loc: By Edinburgh , Scotland
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Hi Milt
yes i got a pair a few weeks ago. http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3391506/page/3/view/collapsed/sb/5/o/all/fpart/1
My current idea or ideal for terrestrial views Steve are hand-held and low power,but i guess you could leave a pair mounted.i have some cracking views over the "Firth of Forth" from my front door,which includes some wee islands...
Brian
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" Gentlemen only ever use Refractors "
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Mark9473
Post Laureate
Reged: 07/21/05
Posts: 3204
Loc: 51°N 4°E
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Brian, try looking at Jupiter during twilight.
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Mark
Leica 8x20; Vixen 8x42; Swift 8.5x44, 10x50 and 20x80; TS 7x50; Orion 15x63; Docter 15x60
WO Megrez II 80 FD + Baader 90° T2 Amici
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milt
professor emeritus
Reged: 09/13/04
Posts: 551
Loc: Arizona
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Quote:
yes i got a pair a few weeks ago.
Brian, sorry I completely missed that thread. So, a belated congratulations!
I recall from a Takahashi group that the biggest danger to the exposed CaF2 lenses in the FS series is extreme thermal shock, such as using a hair drier to defog a very cold lens, or even worse spilling a hot liquid on it. When observing in below-freezing conditions it is recommended to put lens cover(s) on and the instrument back in its case outside so it can warm up slowly once the case is inside. This also prevents condensation and is a good idea for any telescope or binocular.
As to viewing bands on Jupiter there is no question the Tak will do it. In addition to viewing at twilight, try verifying that you have your focus spot-on by using a bright star first. Often you can also pick up more detail by using averted vision.
Enjoy,
Milt
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mooreorless
Just worried
Reged: 07/05/05
Posts: 1821
Loc: Cornpropst Mills,Huntingdon,Pa
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Hi Brian, Now I understand, I guess I should of realized.Have fun with the Tak. :-)
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Regards,Steve M
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medinabrit
professor emeritus
Reged: 10/27/04
Posts: 648
Loc: medina ohio USA.
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Tak astronomers are also an exellent daytime binocular.
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Solar B
scholastic sledgehammer
Reged: 02/28/07
Posts: 908
Loc: By Edinburgh , Scotland
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Thanks Milt & Steve
I was given the same advice at the Star Party i was at re the Thermal shock,from a gentleman with an FS78,so i will be very careful,in both cool down and warm up exposure.
I should have bought a pair of Prominars 
Will keep trying on good old Jupiter to.
Its true that they do work well during the day but im pretty sure their real niche is astro use,Medinabrit.
Brian
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" Gentlemen only ever use Refractors "
Edited by Solar B (11/02/09 04:07 AM)
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