Hi all.

Let me start by saying that this forum has a wealth of great information not only with regard to astronomy stories, but also astrophotography and astronomical equipment.

I started reading and researching this particular part of the forum with the initial intention of purchasing my first telescope. But after reading responses from amateur astronomers who have a great deal more of experience than me and anyone I know, I realized that it would probably be a better idea to start out with binoculars. I have been naked eye observing for two years in January and am familiar with basic constellations and when and where to view the Planets (I've seen and photographed Mercury, Venus, Mars and Saturn--from what I gather it is somewhat difficult to view planets beyond that naked-eye). Still, I am not comfortable with locating deep sky objects. I think binoculars will give me invaluable experience in finding these objects, and truly learning the night sky.

I have read the sticky thread above and have visited most of the websites listed in it. Still, I consider myself a novice in the realm of binoculars and need some advice on my first purchase.

Any and all advice is greatly appreciated. Thank you in advance!

I have found a few binoculars that I am considering buying. My question to the more experienced astronomers out there is basically will these binoculars suffice and are they quality?

1. Celestron Ultima DX 8x56 http://www.celestron.com/c2/product.php?ProdID=174
-- BaK-4 glass
-- fully multi-coated lenses
-- exit pupil = 7mm

2. Nikon 7x50 Action Extreme ATB Binoculars http://www.binoculars.com/binoculars...b.cfm#navbar=a
-- Multi coated optics
-- Exit pupil = 7.1 mm
-- BaK glass


I am leaning more towards the Celestron binoculars right now. Even though they are slightly larger, I think I would be able to hold them steady (only 35oz and I have large hands). Also, I am younger (24) and have good eye vision, so I don't think that the exit pupil would be too much. But, as stated before, I am still a novice. All advice and any suggestions are welcome!

Thanks and clear skies.

Any of the binoculars you mentioned would be good starter (and beyond) instruments!
Personally, I am using a pair of $25 7x50s (Wal Mart specials) to tide me over until my 25x100s (Orion) arrive! Even "cheap" binoculars will show you more than you could study in a lifetime.

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I've got a great pair of 12x24 Bushnell binoculars that I've had for many years. Great for looking at moon features.

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As already mentioned, I doubt you'll see much difference between them. Main one you'd notice is the smaller FOV in the Orion. That goes with higher power with the same style of eyepiece and prism design. Getting a wider fov means a different eyepiece design and bigger prisms adding to weight. Either will serve you well.

I use two main pair for night viewing, 7x35 wide angle (about 9.5 degrees) and a pair of 10x50s. Both Bosch & Lomb (which doesn't make them any more except under the Bushnell brand). I use the 7x35 most as they are very light and I like the wide field. I see fainter stars in the 10x50 and a few more small galaxies. Both show both halves of the Veil and are great for most purposes. They are also over 40 years old, the 7x35's more like 55 or so. I've never felt a need for any others.

Of the two you are looking at I'd think Nikon would use BAK-4 glass in the prisms but since they don't say I'd lean to the Orion ones unless you can look through the Nikon's in a store. If so point them at a bright wall, and look at the exit pupil from a distance (not with your eye in viewing position but back and at an angle so you see the light coming out of the eyepiece). If it is square pass on them. For night viewing they need to appear round for most light transmission. -- most wide angle will be square however. A penalty for going wide I suppose.

Rick

The Celestron Ultimas are a very fine line of binoculars. The very best view of Comet Hyakutake that I had when it was close to the Earth in the spring of 1996 was through a friend's 8x56 Celestron Ultima. I've also used the Ultima 7x50s and 10x50s. I'm not familiar with the Nikon model.

However, if you're going to be observing primarily from sites that are light polluted to any extent a 10x50 binocular will probably make more sense, since your pupils won't dilate to 7mm anyway in those locations.

Dave Mitsky

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Thanks all for the advice.

I live in a city of about 85,000 so it is fairly light polluted here. But I live in Northern Minnesota and there are no other large cities around. As a result, I can drive 15-20 miles up the shore of lake superior, I find very clear skies. Also, I move back and forth from here to the Upper Peninsula of Michigan where light pollution is a non issue. I am going to go with the celestrons.

Thanks again for the advice.

Unless you're under 30, I might consider avoiding the 7X50's or 8X56's, simply because it's very unlikely your pupils will dialate to the full exit pupil provided by either of those binocs. To find exit pupil, divide the aperature by the maginifcation. Either of those will yeild a 7mm exit pupil. However, as we age, our exit pupil drops from a maximum of 7mm (when fully dark adapted in a dark sky) to around 5mm. A 10X50 might be a better choice.

Good point, I am fond of the view through 7 x 50 and 10 x 50 binocs. Try a flea market, just be careful about the prisms being out of alignment. You should be able to bargain to around 10 dollars for a decent pair. But be careful of the telescopes, they run to stopped-down junk.

Then you can put your money into a holder for the binoculars. S&T has had a lot of nice home made holder designs over the years. If you can't manage a holder, an ordinary lawn chair (flea market again, 3 to 5 dollars) is a big help.

edit: My best view of comet Holmes so far has been through an ordinary pair of 7 x 50's.

Even when I was young enough for a 7mm exit pupil I prefered 5mm for binoculars. I view from a mag 6.5 zenith limiting magnitude site so light pollution isn't the problem. I live about 2.5 hours west of Duluth that Gob332 mintions and in much darker skies. To me, the 7mm exit pupil gives such a bright sky, contrast is too low. I saw more at a 5 mm exit pupil even when young. So I quickly retired my 7x50's and used the 7x35 pair. Even with the smaller objective I could see fainter objects than I could in the 7x50's. For fainter stuff yet, I use the 10x50's. Larger than that I can't hold steady. To me, a stand, no matter how comfortable takes away from the reasons I use binoculars in the first place.

I fellow I know who died recently was an aide to Gen. MacArthur during WWII. He took a pair of 25x150's off a Japanese bunker. Now that was a pair of binoculars! They needed one heck of a support structure! I bet they weighed over 30 pounds. I don't know what happened to them after he died. Since I'm entering my 7th decade of stargazing I'm doubt I even get to 5mm any more but those 6mm exit pupils seemed too low of contrast for me. I'd have preferred something around 30x for better contrast.

Rick

I'm 24, so from what I have been reading a 7mm exit pupil should be about right for me assuming I am observing from darker skies. I have one question though. As I age, will the view from these binoculars deteriorate? That is, what real impact will the exit pupil have?

As the eye ages it opens less, so some light is wasted, but at the same power, 8 in this case, there's nothing that can give you a brighter image no matter what your pupil size is. When you open only 5mm then 8x40 binoculars will be identical to 8x56 as far as the view is concerned. You lose that extra light so are holding up heavier binoculars than you need but that's all. These are paid for and new 8x40's cost bucks so there's nothing to do but live with it. You can't buy any that will make it any brighter (unless they have built in light multipling tubes of course).

It's just that as the exit pupil of a telescope or binoculars, as long as all sizes we are talking about fit your eye, the "black" sky gets darker faster than the object does so contrast goes up. I saw a rather gray sky even in the darkest of locations with a 7mm exit pupil in any scope or binocular. This is why I preferred 5 mm exit pupils even when my eye would open to 7. The view was higher contrast and I actually saw more, not less of faint things like the Helix, Veil, various star clouds in the Milky Way. etc. I find this true at the telescope eyepiece as well. There I prefer a 4mm exit pupil for contrast of large low power objects if they fit that FOV. Contrast is higher. Something that is often lost in the rush to see the brightest image possible.

While our skies here in northern MN are dark they aren't as dark as other places. There's more sky glow at our latitude (+47.08 for me) to deal with. Even though there's less light pollution here than where I used to live in Nebraska, I've lost 0.2 magnitudes due to sky glow on most nights. Its worse in winter with ice crystals in the air as well. I lose another 0.1 from the ice on a typical night.

Rick

Rick,

Thanks again for the insight. Since you also live in Northern Minnesota I have a question for you with regard to the ice crystals in the atmosphere. From casual naked eye observing I have percieved that on very cold, clear nights the skies look remarkably clear--much more so than on hazy humid nights of summer. Even with these cold, clear nights should I expect to lose magnitude?

Gob332,
The differences RickJ is talking about are extremely subtle. I am not a beginner (far from it) but I doubt I could detect a a difference of 0.1 or 0.2 magnitude in limiting magnitue without very careful scrutiny of a patch of sky I know extremely well.

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Hi Gob332.

I've been using a pair of Mason (Japanese import) 7 x 50s since 1972 and have always enjoyed the view.There have been times where I need to plant my elbows on something solid to damp the vibration, such as observing Alberio. Next to my hand-made 4 1/4 RFT Newtonian, those binocs are probably the most versatile piece of observing equipment I own.

So you observe in the Yooper, eh? Got to see da winter skies up there a few times doncha know. Really dark skies, eh?

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ha yes indeed. And the dark skies are really the only good thing about the U.P.

eh

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