stars_in_my_eyes
sage
Reged: 03/24/08
Posts: 437
|
|
I notice that the Orion Megaview 30x80 binos seem to be discontinued.
It seems that higher mag binos are not as popular as I would expect...why?
Thanks
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12516
Loc: Cumberland, R I , USA42N71.4W
|
|
Perhaps at some point people begin to consider that a binocular of that size is larger, heavier and bulkier than a telescope and a telescope offers a wider variety of powers. My 80mm telescopes weigh in at 5# to 6#, and I can use them from 15x with a 3.5° fov all the way up to 150x.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2423
|
|
That and- in addition to what EdZ said, as the weight and bulk goes up, so does the requirements (cost) of a mount sufficient to satisfactorily mount the binoculars.
edit: But good big ones are sure a pleasure to view through- properly mounted.
--------------------
Wes
Atlantic Beach, FL
Some bino’s from Miyauchi 5x32 Binon's up through Garrett 20x110 Signature's,
Some telescopes from a Stellarvue 80mm NHNG up through a couple of 8” reflectors…
And a wonderful 4.25" Delmarva Shiefspiegler!
Some good friends, made here on C/N.
Oh- several cats and a wonderful wife!
Anyone want a cat???? :-O
"When your work speaks for itself- Don't Interrupt" -Gamble Rogers
Edited by Wes James (08/16/08 01:54 PM)
|
Tony Flanders
Carpal Tunnel
Reged: 05/18/06
Posts: 2062
Loc: Cambridge, MA, USA
|
|
stars_in_my_eyes asked:
Quote:
I notice that the Orion Megaview 30x80 binos seem to be discontinued. It seems that higher mag binos are not as popular as I would expect...why?
And EdZ answered:
Quote:
Perhaps at some point people begin to consider that a binocular of that size is larger, heavier and bulkier than a telescope ...
I'm not convinced by this answer. There's no reason that 30x80 binoculars need to be significantly bigger than 20x80s, which are popular. And 30x80s certainly show much fainter objects, and much more detail in bright objects, than 20x80s.
From the manufacturer's point of view, high magnification is hard to pull off because it places more stringent demands on collimation and on the optical quality of the objectives. But if the manufacturers can make 30x80s that work well at a reasonable cost, why don't people buy them?
Perhaps a better way of putting it is: why are binoculars with exit pupils smaller than 3 mm unpopular for astronomy? The question is every bit as valid at 50 mm or 30 mmm as at 80 mm.
People who have never looked through 10x30 binoculars sneer that my IS 10x30s can't be any good for astronomy because their exit pupil is too small. The fact that I can see most of the Messier objects through these binoculars doesn't seem to deter the doubters.
One reason, no doubt, is fashion. It used to be believed (for no good reason at all) that any exit pupil smaller than 7 mm was undesireable for astronomical binoculars. Fashion in exit pupils has been creeping steadily downward, and it may yet get as low as 2.5 mm.
But there's also an objective reason. There's a handful of people who really abhor viewing with one eye, or who have physiological problems doing so because of floaters or other problems. But in my experience, most people who use both binoculars and telescopes for astronomy feel much as I do. As far as I'm concerned, using two eyes is nice, but it's not all that big a deal. One eye, two eyes, it's all much the same to me.
So why do people like me use binoculars at all? Because there's one place where binoculars objectively excel -- where they do things that monoculars scopes simply can't match. Namely, low-power, wide-field viewing. The only way to replicate the view through 20x80 binoculars with a monocular telescope would be with an aperture around 120 mm. That would deliver a 6-mm exit pupil, which is bigger than my eyes can handle. In other words, no monocular telescope can show me a view equivalent to what I see through 20x80 binoculars.
And even for people who can handle a 6-mm exit pupil, it would be using the inefficient outer part of their eye's lenses. So at exit pupils of 4 mm, binoculars are hard to beat, and at exit pupils wider than 5 mm, binoculars have no competition.
By contrast, the view through 30x80 binoculars would be quite easy to replicate with a monocular scope. Maybe not subjectively -- one eye is never the same as two. But objectively, a 120-mm scope at 30x would show everything that 30x80 binoculars can, and maybe more. That would deliver a 4-mm exit pupil, which is easy for just about everyone to handle.
So while binoculars are an option in this category of viewing, they're not a necessity, as they are at wider exit pupils.
--------------------
Tony Flanders
eyeglasses
6x15 and 8x32 monoculars
8x25, 7x35, 10x30 IS, 10x50, and 15x70 binoculars
70mm and 100mm achromatic refractors
4.5", 7", and 12.5" Dobs
|
Parker Nite Fly
member
Reged: 02/05/06
Posts: 99
|
|
Quote:
I'm not convinced by this answer. There's no reason that 30x80 binoculars need to be significantly bigger than 20x80s, which are popular. And 30x80s certainly show much fainter objects, and much more detail in bright objects, than 20x80s.
Thank you Tony for this post. This is starting to make some sense to me now. The exit pupil with a very comfortable 9mm plossl on my F6 dob would be 1.5mm correct? So I am already agreeing without knowing it that an exit pupil less than 5mm is comfortable. The difference is in the dob I am at 133x instead of 30x. On my 130ST (F5) at 26x (25mm) I am at 5mm exit pupil. But I am limited to one eye viewing.
Now to help me understand further what is the visual difference between a 30x80 with two eyes observing and my F6 scope at 26x? It probably isn't that simple a question but considering similar quality can you offer some thoughts?
--------------------
Hardin DSH-8
Orion SpaceProbe 130ST
11x56 Oberwerk
7x35 Jason (don't laugh - you'll hurt its feelings)
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12516
Loc: Cumberland, R I , USA42N71.4W
|
|
Binocular - Scope - Binocular Vision equivalents
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
BobinKy
scholastic sledgehammer
Reged: 04/27/07
Posts: 930
Loc: Country road
|
|
Tony--
Thank you for your comments on exit pupil--a subject where I really want to learn.
EdZ--
Thank you for the binocular-scope-binocular vision links. There is some really good stuff there.
--------------------
Bob
38° Kentucky, USA
|
CESDewar
GorillAstronomer
Reged: 01/16/05
Posts: 1802
Loc: Morganton, GA, USA
|
|
There are some reasons why this is so. With higher-power binoculars, it becomes increasingly essential to have them mounted, and this leads to two options: (a) tripod mounting, which is still inconvenient, unless the binoculars have 45° or 90° oculars, or (b) a p-arellelogram type mount which also requires some kind of chair that allows a near-supine position for viewing.
In the case of (a) such binoculars have typically commanded a premium price tag - in the case of (b) the mount has commanded a premium price. People who spend $400 on say a pair of Oberwerks 25x100 binoculars or equivalent (certainly a fine buy) are a bit reluctant to spend an equal or larger greater amount of money to mount them (although it's a very worthwhile investment).
Certainly for me, this is a compelling reason why I use my Canon 18x50 binoculars so frequently - the freedom from a mount is very compelling, although I do use a nice chair for viewing near the Zenith.
--------------------
|
hallelujah
Carpal Tunnel
Reged: 07/14/06
Posts: 1639
Loc: Colorado Rocky Mt. High
|
|
Quote:
I notice that the Orion Megaview 30x80 binos seem to be discontinued.
It seems that higher mag binos are not as popular as I would expect...why?
C O S T!!!! 
Orion MEGAView 30x80mm binocular $500 + S & H
Manfrotto 3246 tripod/501HDV Head $460 + S & H
One Inch Center Post Extension $25 + S & H
Not too many people willing to part with $1,000.00
--------------------
Pentax 12x50mm PCF WP II FMC/WP/FP
Pentax 16x60mm PCF WP FMC/WP/FP
Pentax 20x60mm PCF WP II FMC/WP/FP
Orion 12x63mm Mini Giant FMC/JAPAN
Orion 15x70mm Little Giant II FMC/JAPAN
Orion 16x80mm Giant FMC/JAPAN
Orion 20x70mm Little Giant II FMC/JAPAN
Orion 30x80mm MEGAView FMC/JAPAN
Barska 30x80mm X-Trail LW FC
Burgess Optical Series II 20x90mm FMC/WP/FP
Handel's Messiah**Hallelujah! For the LORD God Omnipotent Reigneth
|
Vincent33
member
Reged: 09/18/07
Posts: 95
|
|
My two cents ...
IMHO it's not a problem with cost, exit pupil or the need for a tripod (meaning for "tripod" everything to hold a binoculars), because to use a more than 15x needs always a support; a FIXED enlargement of 30x is halfway from a wider FOV and the need to have a better vision of planets, moon and narrow objects. I would far more prefer something with interchangeable eyepieces, to switch with the SAME binoculars mounted from a wider view to more detailed one (that's why I'm cosidering something like a 100mm with 90° view).
Bye.
|
EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12516
Loc: Cumberland, R I , USA42N71.4W
|
|
It is correct that the Megaview is rather light. At 5#4oz. it could be mounted on the Bogen 3011/3130 or even the Orion Paragon HD-F2. So, a mount for this binocular can be had for under $100. So total package cost would be about $590 to $625.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
|
hallelujah
Carpal Tunnel
Reged: 07/14/06
Posts: 1639
Loc: Colorado Rocky Mt. High
|
|
Quote:
It is correct that the Megaview is rather light. At 5#4oz. it could be mounted on the Bogen 3011/3130 or even the Orion Paragon HD-F2. So, a mount for this binocular can be had for under $100.
edz
I have tried my Manfrotto 3021BN tripod with 501 head, and although it is workable, using a tripod without a geared center cloumn leaves much to be desired, in my opinion. 
Also, the overall height was lacking for me.
--------------------
Pentax 12x50mm PCF WP II FMC/WP/FP
Pentax 16x60mm PCF WP FMC/WP/FP
Pentax 20x60mm PCF WP II FMC/WP/FP
Orion 12x63mm Mini Giant FMC/JAPAN
Orion 15x70mm Little Giant II FMC/JAPAN
Orion 16x80mm Giant FMC/JAPAN
Orion 20x70mm Little Giant II FMC/JAPAN
Orion 30x80mm MEGAView FMC/JAPAN
Barska 30x80mm X-Trail LW FC
Burgess Optical Series II 20x90mm FMC/WP/FP
Handel's Messiah**Hallelujah! For the LORD God Omnipotent Reigneth
|
hallelujah
Carpal Tunnel
Reged: 07/14/06
Posts: 1639
Loc: Colorado Rocky Mt. High
|
|
Quote:
a FIXED enlargement of 30x is halfway from a wider FOV and the need to have a better vision of planets, moon and narrow objects.
I don't understand this statement, please clarify.
--------------------
Pentax 12x50mm PCF WP II FMC/WP/FP
Pentax 16x60mm PCF WP FMC/WP/FP
Pentax 20x60mm PCF WP II FMC/WP/FP
Orion 12x63mm Mini Giant FMC/JAPAN
Orion 15x70mm Little Giant II FMC/JAPAN
Orion 16x80mm Giant FMC/JAPAN
Orion 20x70mm Little Giant II FMC/JAPAN
Orion 30x80mm MEGAView FMC/JAPAN
Barska 30x80mm X-Trail LW FC
Burgess Optical Series II 20x90mm FMC/WP/FP
Handel's Messiah**Hallelujah! For the LORD God Omnipotent Reigneth
|
Vincent33
member
Reged: 09/18/07
Posts: 95
|
|
Quote:
Quote:
a FIXED enlargement of 30x is halfway from a wider FOV and the need to have a better vision of planets, moon and narrow objects.
I don't understand this statement, please clarify.
I mean that 30x is a high enlargement, a very specialized one; you could need it just to look at bird's nests, moon's details, but it's still far from offering a wide view and maybe too low to look at details. So, as a single instrument, it enters in a 'dead zone' where spotting scopes (or binoculars) with variable enlargement are the right choice. Always IMHO, cheers.
|
hallelujah
Carpal Tunnel
Reged: 07/14/06
Posts: 1639
Loc: Colorado Rocky Mt. High
|
|
Quote:
So, as a single instrument, it enters in a 'dead zone'
 http://en.wikipedia.org/wiki/Dead_zone_(ecology)
--------------------
Pentax 12x50mm PCF WP II FMC/WP/FP
Pentax 16x60mm PCF WP FMC/WP/FP
Pentax 20x60mm PCF WP II FMC/WP/FP
Orion 12x63mm Mini Giant FMC/JAPAN
Orion 15x70mm Little Giant II FMC/JAPAN
Orion 16x80mm Giant FMC/JAPAN
Orion 20x70mm Little Giant II FMC/JAPAN
Orion 30x80mm MEGAView FMC/JAPAN
Barska 30x80mm X-Trail LW FC
Burgess Optical Series II 20x90mm FMC/WP/FP
Handel's Messiah**Hallelujah! For the LORD God Omnipotent Reigneth
|
Vincent33
member
Reged: 09/18/07
Posts: 95
|
|
Quote:
Quote:
So, as a single instrument, it enters in a 'dead zone'
http://en.wikipedia.org/wiki/Dead_zone_(ecology)
http://www.imdb.com/title/tt0085407/
I was trying to say it's an enlargement that is more for other kind of instruments, like spotting scopes ... and that English is not my motherlanguage ... :-)
|
hallelujah
Carpal Tunnel
Reged: 07/14/06
Posts: 1639
Loc: Colorado Rocky Mt. High
|
|
Quote:
English is not my motherlanguage ... :-)
Vincent,
So, where DO you live?
Don't mind me, it's just THE FULL MOON, my circuitry gets scrambled during this time of the month.
Maybe it's male hormones or something. 
--------------------
Pentax 12x50mm PCF WP II FMC/WP/FP
Pentax 16x60mm PCF WP FMC/WP/FP
Pentax 20x60mm PCF WP II FMC/WP/FP
Orion 12x63mm Mini Giant FMC/JAPAN
Orion 15x70mm Little Giant II FMC/JAPAN
Orion 16x80mm Giant FMC/JAPAN
Orion 20x70mm Little Giant II FMC/JAPAN
Orion 30x80mm MEGAView FMC/JAPAN
Barska 30x80mm X-Trail LW FC
Burgess Optical Series II 20x90mm FMC/WP/FP
Handel's Messiah**Hallelujah! For the LORD God Omnipotent Reigneth
|
Vincent33
member
Reged: 09/18/07
Posts: 95
|
|
Quote:
Quote:
English is not my motherlanguage ... :-)
Vincent,
So, where DO you live?
Central Italy ... now I'm in Rome but soon I'll escape to a little town 20 miles North ...
Quote:
Don't mind me, it's just THE FULL MOON, my circuitry gets scrambled during this time of the month.
Maybe it's male hormones or something.
I was born in a day of full moon ... does it means something? Cheers.
|
Tony Flanders
Carpal Tunnel
Reged: 05/18/06
Posts: 2062
Loc: Cambridge, MA, USA
|
|
Quote:
I mean that 30x is a high enlargement, a very specialized one ... it's still far from offering a wide view and maybe too low to look at details.
There's some truth to this. It's not that 30X is an oddball magnification in an of itself. For instance, it's a lovely low-power wide-field magnification in my 7-inch Dob. But 30X is indeed a bit of a "dead zone" with respect to 80 mm of aperture.
I'd say that true widefield viewing includes exit pupils from 4 mm to 7 mm -- or to state precisely the same thing in different terms, magnifications from 3.5X to 6X per inch of aperture.
But for viewing individual deep-sky objects up close, exit pupils between 1 and 2 mm (magnifications from 12X to 25X per inch of aperture) almost always show the most detail, and let you see the faintest objects. People often stretch that to 2.5 mm (10X per inch) to gain a little extra field of view while taking only a minor hit in how much detail they can see.
That leaves exit pupils of 2.5-4 mm (magnifications of 6X to 10X per inch) as a kind of neither-here-nor-there. There are always going to be some situations where this is the absolutely best possible magnification, but they're pretty rare. The one big exception is when using aggressive filters like an O-III or an H-Beta, where 2.5-4 mm turns out to be a sweet spot. But few people use filters on binoculars; it's tricky to arrange.
It's true that the Canon image-stabilized binoculars, which I and many other people think are just wonderful for astronomy, happen to have exit pupils mostly in this "dead zone." But that's really just a practical compromise. I would love to have 50 mm of aperture to go with the 10x of my image-stabilized binoculars if it were available at reasonable cost and weight. But in fact, the closest I can come (the 10x42s) are far out of my price range and not very attractive in terms of weight and bulk.
Conversely, one could in theory go the other way and get a big exit pupil by reducing the magnification. 6x30 binoculars have much wider fields of view than my 10x30, and they could in theory be fitted with image stabilization. But really, image stabilization would be a waste of money at such a low magnification.
So it turns out that for practical reasons having nothing to do with optics and a lot to do with mechanical engineering and economics, 3 mm is a pretty nice exit pupil for image-stabilized binoculars.
--------------------
Tony Flanders
eyeglasses
6x15 and 8x32 monoculars
8x25, 7x35, 10x30 IS, 10x50, and 15x70 binoculars
70mm and 100mm achromatic refractors
4.5", 7", and 12.5" Dobs
|
Mike Rapchak
sage
Reged: 11/17/06
Posts: 449
Loc: Indiana, USA
|
|
My personal opinion - which may or may be representative of other bino viewer's decisions when considering the purchase of such an instrument: My initial reaction is that 30x is too much for an 80mm bino. Not only would I be concerned with dim views (exit pupil), the FOV would be too small. To me these factors work against the resaons why I like using binos in the first place (a wide view with adequately bright images). Also, 30x in an short-FL 80mm achromat is not going to cut it as far as clean, detailed views of astronomical objects is concerned; that's what a telescope is for. Again, this is my personal opinion/reaction to these 30x80s; I've never looked through a pair so I can't say for sure that it's an accurate opinion. Still, this isn't what I want in a bino. I'd have to go to a 100mm- or larger pair w/interchangeable EPs to justify using such an instrument (higher mag, narrow FOV) instead of a telescope. I owned a pair of 25x100s for a short time in late 2006. I actually found them less than satisfying visually and use-wise; meaning that for as big as they were the views weren't all that rewarding, especially considering their size/weight/bulk and the need for a stout tripod. Again, I felt that this size/magnification/FOV was approaching what I call telescope territory. In these ways everything about them was a compromise re my reasons why I enjoy binocular viewing. I may be in the minority here, but this is how I see it.
I returned these binos (though the main reason was defective optics) and swapped for a pair of Vixen ARK 11x80s (based largely on my memories of the overall performance of my late-'70s pair of University Optics 11x80s). The Vixens were quite a delight; half the weight of the 25x100s, larger FOV, and considerably brighter images. Yet after a while I started desiring more magnification as I aleady owned a beautiful pair of 10x50s (Celestron Nova). So I swapped the 11x80s for a pair of Vixen 16x80s. These are even more enjoyable to use than the 11s, yet they're a bit of a compromise. I stated wondering if I shouldn't have opted for 20x80s instead, and soon realized that in the end it wouldn't make that much difference, and I'd then be even further away from my primary reasons for using binoculars in the first place. Although the Vixens are wonderful and perform great, they're still a bit closer to that "no man's land" (a/k/a "dead zone") between convenient, hand-held, wide-angle, low-power viewing (wich are the things I love binos for) and a telescope. They leave me with a case of aperture fever in that they whet my appetite for more magnification. IMO this can only be truly satisfied with a telescope as binos aren't really meant/designed for such performance. Thus I find myself grabbing my Celestron 10x50s as often or more than I do the Vixens since the Celestrons more satisfyingly conform to my ideas of bino use/viewing; plus they're truly grab-&-go as they're relatively small and light and do not require a tripod.
Sorry for the long ramble; but as a bino user these are the reasons why I'd never consider a 30x80 pair. And as someone else here mentioned, price would also be a factor. Considering my priorities there's no way I could justify it. To illustrate this point, I've found myself occasionally drooling over those big Oberwerks - what are they, 25x120s? Yet for the total cost with the mount and an adequate tripod I could almost buy a Celestron CPC 1100 - which is the route I'd go since the big Obies are, IMO, in "telescope territory".
I'm sure that there are others who will disagree with me on all this, which is fine since there are many individual opinions/preferences regarding this topic. Still, I'm thinking that these may well be at least some of the reasons why binos like the 30x80 are not that popular.
Mike Rapchak Jr.
|
BobinKy
scholastic sledgehammer
Reged: 04/27/07
Posts: 930
Loc: Country road
|
|
Tony--
Very interesting post on exit pupil. Thank you.
--------------------
Bob
38° Kentucky, USA
|
edwincjones
Post Laureate
Reged: 04/10/04
Posts: 4359
|
|
also, at some point, it makes more sense to use a telescope with/without
binoviewers
for me, that point is around 1.5-2 degrees FOV
edj
--------------------
n w arkansas
Binocular, Solar, General Amateur Astronomy
|
Vincent33
member
Reged: 09/18/07
Posts: 95
|
|
Quote:
The one big exception is when using aggressive filters like an O-III or an H-Beta, where 2.5-4 mm turns out to be a sweet spot. But few people use filters on binoculars; it's tricky to arrange.
I have the tentation to arrange these filters on my Canon 15x50 IS, because they have a standard 58 mm filter thread,. I've searched a LOT on eBay and Google for "filters adapters" of this kind, until I found them ... in Italy!
There should be a little loss in aperture (about 50 > 45 mm), but with these adapters every 2" eyepiece filter can be used on the Canons. What do you think should be the "first" filters to use/buy? Cheers.
|
Vincent33
member
Reged: 09/18/07
Posts: 95
|
|
Quote:
My initial reaction is that 30x is too much for an 80mm bino. Not only would I be concerned with dim views (exit pupil), the FOV would be too small. To me these factors work against the resaons why I like using binos in the first place (a wide view with adequately bright images). Also, 30x in an short-FL 80mm achromat is not going to cut it as far as clean, detailed views of astronomical objects is concerned; that's what a telescope is for. Again, this is my personal opinion/reaction to these 30x80s; I've never looked through a pair so I can't say for sure that it's an accurate opinion. Still, this isn't what I want in a bino. I'd have to go to a 100mm- or larger pair w/interchangeable EPs to justify using such an instrument (higher mag, narrow FOV) instead of a telescope.
I do agree, and that's what I've tryied to say in a former message. Bye.
|
BobinKy
scholastic sledgehammer
Reged: 04/27/07
Posts: 930
Loc: Country road
|
|
Quote:
EdJ wrote--
also, at some point, it makes more sense to use a telescope with/without
binoviewers
for me, that point is around 1.5-2 degrees FOV
EdJ--
Thank you for expressing major issues in such simple terms--as you always do.
As for me, I have this very bad habit of mucking issues up by over-complicating them.
Thanks again.
--------------------
Bob
38° Kentucky, USA
|
Swedpat
Pooh-Bah
Reged: 02/18/05
Posts: 1033
Loc: Boden, Sweden, Scandinavia
|
|
Thank you Mike for your point of view, which I find valuable and interesting.
About the 30x80 binocular I think you are right. The 2,7mm exit pupil makes this glass to be a daytime long distance, and astronomy binocular. At dawn and dusk the image will be quite dim. Therefore it will lose the usual point with a large binocular to provide a clear image under low light conditions. Also the TFOV will be narrow, and it will, as you call it, approach "telescope territory".
Regards, Patric
--------------------
*2,3x40 Constellation View Wide-Bino
*Leupold 6x30 Yosemite
*Leupold Katmai 6x32
*Swarovski SLCNew 7x42B
*Bresser (Lidl) 10x50
*Oberwerk 11x70
*No name (Kunming) 15x70
*Scopos ED APO 66
*Meade 5000 26mm Plössl, Vixen LV 10/5mm
Psalm 19:2
|
Joe Ogiba
Post Laureate
Reged: 02/14/02
Posts: 3340
Loc: NJ USA
|
|
With my Denk II in my C9.25 I could get the power down alot by using my 40mm Plossls in .66x focal reducer mode and then switch to 20mm Pentax XW's for a wide 70° AFOV or 13mm Ethos for a 100° AFOV. The highest power I use in my binoculars is 32x (RA-88-SA's) and higher than that I use my Denk II binoviewer with a myriad of eyepice/scope combinations.
--------------------
Pentax PF-80ED
Meade 102ED APO
Orion EON 72
120ST
Apex 127
C6 XLT
CR150
C9.25
XT10
Zeiss 7x42 FL
Canon 10x42L IS WP
15x50 IS
12x36 IS II
Garrett Optical 28x110 HD-WP Signature Series
Oberwerk BT-80 45
Apogee RA-88-SA
Denk II Power x Switch binoviewer w/13mm Ethos, 20mm Pentax XW's, 20mm Widescan III's.
|
Mr. Bill
Carpal Tunnel
Reged: 02/09/05
Posts: 2748
Loc: Just passing through.....
|
|
Quote:
But for viewing individual deep-sky objects up close, exit pupils between 1 and 2 mm (magnifications from 12X to 25X per inch of aperture) almost always show the most detail, and let you see the faintest objects. People often stretch that to 2.5 mm (10X per inch) to gain a little extra field of view while taking only a minor hit in how much detail they can see.
That leaves exit pupils of 2.5-4 mm (magnifications of 6X to 10X per inch) as a kind of neither-here-nor-there. There are always going to be some situations where this is the absolutely best possible magnification, but they're pretty rare. The one big exception is when using aggressive filters like an O-III or an H-Beta, where 2.5-4 mm turns out to be a sweet spot. But few people use filters on binoculars; it's tricky to arrange.
Your assessment may be appropriate when observing in typical suburban conditions; however, when viewing in the darkest night skies (mag 7+) I would suggest the following is true....
I find that 2.5 to 5mm exit pupil to be optimal for viewing large scale structure in the MW arms...that is light and dark nebulae (Sharpless and Barnard nebulae)and starfields and open clusters.
I normally observe at 25x (4mm ep) with the BT100s and find it to be a wonderful balance of contrast/wide fov.
I also find 42x (2.33mm ep) using the 14mm Denk eps in the BTs to be excellent for medium power where more detail is desired.
I don't like exit pupils less than 1.5mm....if I need more magnification, I get a bigger aperture.
--------------------
10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork m |
Previous
Index
Next
Threaded
Edit
Reply
Quote
[Re: