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Anonymous
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Hi again,
I've been doing a lot of reading here and found some wonderful info but I still don't understand the whole astronomy thing....if you are using binoculars for star gazing...wouldn't the most powerful mag bring them in the closest?...I notice many here reccomending some in the 10-12 power range...wouldn't a 22 or higher be more suited for planet watching? Or does it not matter since they are so far away? thanks in advance...Dave
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KennyJ
Reged: 04/27/03
Posts: 10143
Loc: Lancashire UK
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If the sole intention is to view PLANETS ,forget binoculars really.
STARS are a completely alternative boiling appliance of veterbrate ("different kettle of fish" in the UK )
Stars are never going to look any BIGGER no matter which binoculars or which magnification you use.
That is not the aim. Stars are TOO far away and moving further away from us every second.
In fact , in simple terms , the qualities of a binocular are rated in how much SMALLER a star can be made to appear !
Strange but true.
The "holy grail" of the star-gazing binocular enthusiast revolves around a visual impression of diamonds against a matte black backdrop , which in optical terms embraces "sharpness" , "contrast" and the number of stars that can be seen , and for some people , an optical illusion that the universe is "flat" at the expense of number of stars seen in a given field of view , but for others a preference to enjoy a more "natural" wider picture with warts and all.
Somewhere in between is what most of us settle for , and if you want to magnify with an instrument that either magnifies more than about 12x , or has an objective lens above around 60mm -- for reasons of shaky image or sheer weight, or both , you are in the realms of having to purchase , carry and set -up tripods , mounts and all the other paraphenalia and inconvenience that goes with all of that.
There are many different kinds of astro binocular viewing, with differing aims and objectives ( no puns intended )
Regards --Kenny.
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Two eyes and a preference to use both
Zeiss 7 x 42 BGAT
Captain's Helmsman 7 x 50
Nikon 10 x 42 Superior E
Swift Audubon Kestrel 10 x 50
Helios 15 x 70 Observation
Strathspey 20 x 90
Televue 76 APO
Zeiss 85 Diascope
Helios 102 f5 refractor
Various eyepieces barlows tripods mounts etc.
Panasonic Lumix DMC - TZ5 digital camera
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Anonymous
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Ah.....thank you for that....I'm begining to see the big picture...by the way...congrats to you brits on the Office win and Ricky Gervais....it's my favorite show...
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Anonymous
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Here are some things I consider when looking for binoculars for astronomy.
I want the biggest magnification/FoV I can comfortably use. When first starting astronomy it will be very hard to find objects in the sky, so a wide FoV is very helpful- and always will be. But as you get more and more familiar with the sky a smaller and smaller FoV will be usable, meaning that as long as there isn't too much shake you can use higher magnifications. However, a big FoV is still useful- even for experts. But I (a newbie) prefere to use as much magnification as I can. The binoculars I use have a FoV a little over 4*, this makes it very difficult to find things with, but I am getting better with it at certain parts of the sky, because I'm so familiar with them.
Also, it's kind of fun to use a restricting FoV, because it makes it much more of a challenge to find things, I like that(Just make sure to use the biggest AFoV you can, this way you can max out the magnification). Also, the trade off between FoV is made up for by the much more pleasing image. Star colors jump out at you, and normally the exit pupil in larger binoculars are less than in smaller ones, so the sky looks darker- although it would be possible to find a smaller pair like this, but then the stars wouldn't be as bright.
If you're looking for a pair of binoculars I would suggest looking into Oberwerk 12x60mm and Oberwerk 15x70mm, just make sure you can hold the image steady enough, if you can't then they will have just lost most of their value.
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Anonymous
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Also, I forgot to say something.
Make sure you know how to adjust the focus properly in both eyes. People may laugh at me for this, but I was doing it completely wrong for more than 2 months! Thankfully I was given help by the members of this forum- specifically Erik D. If you think you might need help with this ask him or anyone else for help, I won't go into it now because it's not neccesary yet, but just keep it in mind.
Here are some of the changes which should be noted when both sides of the binoculars equally match the eyes(No, I haven't actually been able to test this yet because of clouds, but I'm fairly certain this is what I will find.)
Less flairing. Stars and planets will focus into smaller points and circles respectively.
More comfortable viewing. If the binoculars don't match, you may feel slightly dizzy or sick when viewing. This is not normal! It should be just as natural as if you were viewing with your naked eyes.
Hmm, I'm not yet sure what else, perhaps a sharper image, although I'm not quite sure, I think the mind corrects for this except on flairing. Once both sides of the binoculars are focused correctly it will be much easier to find the perfect focus- I do know this to be true, from close range objects.
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Anonymous
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Quote:
I still don't understand the whole astronomy thing....if you are using binoculars for star gazing...wouldn't the most powerful mag bring them in the closest?
In addition to reasons already stated, low power is not only useful but essential if you want to look at extended objects (nebulae and galaxies). If you keep the aperture constant and double the magnification, you are collecting the same number of photons and spreading it into a larger image. Thus the apprent surface brightness decreases. On the other hand if you use too low a magnification, the light beam exiting the eyepiece will be wider than your pupil so some of the aperture is wasted. This beam width is called exit pupil, and you can calculate it by dividing the aperture by magnification. 7mm is as wide as most people's pupils get at night, hence the popularity of 7x50 binocs (7mm exit pupil).
In fact, telescopes and binoculars never increase apparent surface brightness of an object. If it could, it would violate the laws of thermodynamics. So when you look at the Andromeda Galaxy with 7x50 binocs, the surface looks just as bright as with your naked eyes, only 7x larger. If you use 15x50 binocs, it will look 15x larger but 1/4 as bright.
Sorry if you know all this, but I remember it took a while to understand it when I started.
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Anonymous
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Because galaxys are easier to see the larger the exit pupil, it seems that the eye measures contrast by the actual difference in brightnesses between two objects instead of the ratio of the level of brightness based on some 'absolute brightness scale.' This is very interesting.
I keep learning at least 10 new things each day from this forum, it's amazing! 
But what would happen if the level of brightness for each object was reduced by an equal amount(Rather than divided)? I don't think it would get dimmer.. would it change color or something? Would nothing change? Or am I confusing brightness with contrast? I have no idea. And I don't think there's any method that can be used to achieve this, so it's going to need to be done mathamatically.
Edited by Daniel_Schwartz (02/05/04 04:32 PM)
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Anonymous
Unregistered
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I tested it out on a picture editing program, but I'm not sure exactly what it was doing, I think it was still keeping the ratios equal. Does anyone know exactly what's going on when you use brightness and contrast controls on a software program? I assume all software achieves the same thing.
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KennyJ
Reged: 04/27/03
Posts: 10143
Loc: Lancashire UK
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Hi Daniel,
One thing I like about you is that you keep asking questions
Whether or not anyone knows the answers to them all ,or whether or not if they do , they are not members of this forum , or even if they are members who happen not to have seen your question ,or even if they are members who have actually seen your questions, know the answer, but cannot be bothered to reply are all possibilities that are in a way, quite interesting in themselves.
I know NOTHING about software programs , but I do know that the terminology of "brightness" and "sharpness" and "contrast" as applied to T.V set user -adjustable features bear very little if any relationship to the jargon when applied to optical instruments such as binoculars.
I suspect with regard to the term "contrast" in binocular astronomy , there is a bit more to it than differences of what you refer to as "brightness".
At the end of the day ,if you think about it,all these terms such as "brightness" , "sharpness", "contrast" and "resolution" are NOT ONLY "relative", and in some instances inter -related, and doubtless varying in appearance from individual to individual according to individual perception , comparitive acuity and all manner of human eyesight imperfections,BUT ALSO, in the greater scheme of things, only "human attempts" to describe or classify specific aspects of the whole visual experience.
There is no law of physics that rules out the possibility of there being other hitherto undefined "classifications" that in real life experience ,in spite of the absence of such , may nonetheless make contributions to the overall "perceived quality" of a viewed image.
Keep asking the questions , and between us we may learn something !
Regards -- Kenny.
--------------------
Two eyes and a preference to use both
Zeiss 7 x 42 BGAT
Captain's Helmsman 7 x 50
Nikon 10 x 42 Superior E
Swift Audubon Kestrel 10 x 50
Helios 15 x 70 Observation
Strathspey 20 x 90
Televue 76 APO
Zeiss 85 Diascope
Helios 102 f5 refractor
Various eyepieces barlows tripods mounts etc.
Panasonic Lumix DMC - TZ5 digital camera
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Anonymous
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Thanks Kenny!
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