Quick question about binoculars

[OzStarGazer]

Hi,

Sorry if this is a silly question... I have seen a pair of old binoculars in an OP shop. At first I thought I don't need them, but then when I came home I thought they might be good binoculars and also suitable for night vision. So I was thinking of going to the shop again tomorrow to have a better look.

So my question is.... Is there a way to check their quality and also if they are suitable for night vision? The people who work there won't have a clue, so I should have a clue myself. :)

Thanks!

[ZeroID]

Pick them up and look through them basically. :shrug:

I'm using a pair of old Zeniths @ 12 x 50 with some light sheilds on the front and they are surprisingly good. Look for a flat field, no coma or aberration at the edges primarily. Fungus or scratched lenses, drop them. Check mechanicals, focussing, hinges etc.

What sort of price are they asking?

I got mine for $10 so no loss if they didn't work well. I actually got a second pair for nix and combined the good parts. It also gave me the optics for my guide scope. :thumbsup:

[CJ]

Hi Ozstargazer.
I'm no expert but, obviously, have a look through them.
Firstly, can you see double everything? If yes, I wouldn't bother unless they are a good make and can be collimated.
Is the image reasonably bright and not milky?
What size are they? How much are they? What make are they?

I'm happy with my Olympus 10x50's for $130.

Cheers

[OzStarGazer]

Thanks for the replies. They want $30. I will check the brand for a start.
I can quickly check them, but it will be during the day of course. Obviously I can't check them at night. :(
I mean, sometimes you do find bargains, that's why I want to double-check.
Yesterday I found a pair of genuine Christian Dior glasses that look like new for $5 for example.
What are the best binoculars brands by the way?
:thanx:

[Monstar]

I can remember someone say to give them a gentle shake to make sure nothing is loose or has fallen off.

I don't know much about them (and I'm not recommending them as I not used any others)and I know they are nothing special but I got given an old pair of Tasco 8x30mm and was really surprised with how good they are and how much I use them. Beautiful wide/rich fields the ultimate grab n go. Apart from using them on their own they're good for searching for things before going in with the scope.

You mentioned night vision, what are you planning to do? I like following your "experiments" as you called them in an earlier post.

[OzStarGazer]

:) Well, I thought a pair of good binoculars might be useful on holiday for a start. :) Or for quick viewing, even from the window.

I have just read this though re binoculars:
The larger the objective lens, the more light it can gather, which is important in low-light activities such as astronomy or hunting at dawn or dusk.

The same as with telescopes obviously. Unfortunately I actually think they were a bit on the small side, but I will check anyway.

[julianh72]

The same as with telescopes obviously.
Well, yes - binoculars are simply two matched telescopes, so the same rules apply, but the other important factor is that they are going to be used hand-held a lot of the time, which means light-weight and balance in the hand are important (to get a steady view), and you don't want too much magnification, or you simply won't be able to keep a target in view for hand-held use.

Something in the range 7x50 to 10x50 is usually recommended as a good starter pair for general purpose and astronomical use. 50 mm objectives have good light gathering power, while still being light enough for comfortable hand-held use, and have a nice wide field - not too high powered. They are just as useful for daytime terrestrial use as for star-gazing.

The little pocket-sized 8x30s and similar are great for bush-walking, but they have a lot less light gathering power (only 36% of a pair of 50 mm!), and will only improve your night vision a little, but going for 50 mm objectives will make a world of difference.

The big astronomy "light buckets" (15x70, 20x80 etc) really need a tripod to use, and are of limited use for hiking and terrestrial use, but give a fabulous night sky view - as long as you have a good mount and a comfortable chair in which to use them.

[Monstar]

Absolutely, aperture is the name of the game.

If you look at mine straight on they look tiny.

[julianh72]

I want a pair of these:
http://deskofbrian.com/wp-content/uploads/navy-photo-looking-with-giant-binoculars.jpg

or better yet:
http://www.waynesthisandthat.com/images/voyager.jpg
"The telescope I use is a binocular with eight-inch f8 mirrors for objectives. Originally, it was mounted on the motorized mount pictured above that the observer sat in. It gave the impression of flying through the heavens."

[OzStarGazer]

Thanks, I will look for 7x50 or 10x50 binoculars. :)
Although I have to say those in the links are very pretty and really tempt me... :lol:

[Draco]

Apart from the basic things which are
- the lenses are clean
- there are no scratches
- no damages
- good aperture (as others have said) 10x50 for comfortable hand held or if you want to get a tripod then you can go for bigger ones

also ensure they are not ruby coated. these are mostly for antireflective properties but with astronomy you need the most light entering the lens, so a big no no for ruby coated lenses

[ZeroID]

Yeah, should have mentioned 10 x 50 is about the minimum. You need that 50 mm to grab those elusive photons.
Good comment from Chris re collimation ie the two images align. I had a pair that were funny and it ended up being a cross threaded front objective assembly. The threads are very fine and easily mismatched.

[Renato1]

Most important things to do when you see an old pair of binoculars after you've focused them (middle focuser with left eye open, right hand eyepiece focuser with right eye open).
1. Aim at a distant object (50 to 100 yards away) and alternate opening and closing right and left eyes. If the object stays in the same spot, all is well. If the objects jumps between two positions, that's the end of the test, walk away.

2. Less important, focusing on an object, look at other objects going to the edge of the field. Do they look as sharp, or very nearly as sharp as the object in the centre? If not, you'll see mushy stars in the sky. Only the better binoculars are nearly sharp or totally sharp across the field. The cheaper ones can be really bad at the edges, while others, while not perfect can be passable.

3. Does the image look crisp, or hazy/foggy? The better binoculars have nice contrast, and basically what you see in the binoculars is what you see without them in terms of that aspect. Cheaper binoculars aren't quite as good, but still are passable for stars. But sometimes that haziness is because a film or mold has grown inside the glass elements. Not desirable, because it might get worse, but may still be okay on stars, though you'll see a big glow around the moon.

In general, avoid small 8x20 or 10X25 pairs of binoculars, I've never found much use for them. 8X30s and 7X35s I didn't mind when I was a beginner, and found them good for constellations and brighter DSOs. But nowadays, the lowest I'd go is 8 or 10X42, while 10X50s and bigger is usually better.
Good Luck,
Renato

[OzStarGazer]

Thanks, guys. Unfortunately I cannot go today as I am sick. I will have a look tomorrow. I do think they were too small, but your advice is also good for the future. :) I do see binoculars all the time.
I would prefer hand-held binoculars. If I need a tripod I can also use my telescope.

[julianh72]

It is pretty standard advice that the first thing any new star-gazer should buy is a decent pair of binoculars; preferably a pair with reasonable aperture (50 mm +), and preferably a pair suitable for hand-held use, which tends to suggest 10x50 or thereabouts as an ideal first pair. (Not that there's anything wrong with 15x70 etc, as long as you understand the ramifications of the greater weight, smaller field of view and higher magnification for hand-held use.)

Let me highlight a key word: decent!!!

I've been using a cheap no-brand pair of 10x50 binoculars for some time - both for general daytime terrestrial viewing, and especially for night-time star-gazing use. I always thought they were optically "OK" - reasonably bright and sharp, etc. (However, if I'm honest, I always knew they were a little bit rubbish!) I really wanted an affordable pair of decent quality 10x50 binoculars.

Hunting around on the inter-webs, Pentax XCF binoculars seemed to come up over and over, with pretty good reviews. They're listed on many generic discount seller sites, but they're also carried by many more "reputable" optical specialists such as BinTel, which encouraged me to believe that they should be OK, so I dived in and bought myself a pair of 10x50s - and I have to say I'm absolutely delighted. (They're also available in 12x50 and 16x50, but I figured 10x50 was ideal for my needs.)

The XCFs only cost a bit more than no-brand 10x50s, but the build-quality and optical quality compared to my previous pair is chalk and cheese! The XCFs are so much brighter, sharper, and more contrasty, and also have a much wider field of view (6.5 degrees actual / 65 degrees apparent eyepiece field of view, compared to about 4.5 degrees actual / 45 degrees apparent for my old pair). The old binoculars feel like I am looking though a cardboard tube in comparison - a cardboard tube with a slightly greasy bit of glass at one end! :lol:

The coatings, lenses and prisms are clearly (pun intended!) far superior to my old binoculars, and it shows in the image quality. Everything is pin-sharp, right across the field of view, and the difference for star-gazing in particular is almost startling - they reveal a significantly wider expanse of night sky, and easily show much fainter stars and nebulae against the background. They are nicely weighted and balanced, and feel very good in the hand.

I would definitely buy the XCFs again, and I am happy to recommend them to others looking for good-quality budget-priced binoculars - they are a great value buy! Yes, I am sure that you can get an even better view from more upmarket models, but these are superb as an entry-level buy.

Does anyone want to buy a pair of unbranded binoculars? I know where there is a pair going cheap! :rofl:

[brian nordstrom]

Another reason 7x50"s are mentioned alot is the exit pupil is 7 mm that's the diameter
of 50mm divided by the magnifaction of 7 , that is 7mm the perfect size for the average person's dark adapted eye pupil, about 7mm so the eyes get a perfect image, no light waisted.
I got a pair of 8x56 binoculars at am OP shop in Napier NZ many years ago and they are awesome, perfect 7mm exist pupil, great astronomy binoculars , there are bargains out there if you look, good luck.
Brian.

[OzStarGazer]

Thanks,well, last week just before the big wet of the weekend I went to the store again and they had a pair of vintage 10x50 binoculars. I decided to give them a go because they also gave me a free case with them (the original one was lost), and the case they gave me is actually for a DSLR camera and two lenses, which is something I wanted to buy anyway, but it also fits the binoculars perfectly...
The view of the moon was not bad at all... During the day I could also focus etc., but the view was a bit bright during the day (50 lets through quite a lot of light of course)... I have not been able to test them much because of the big wet, but at least they can focus OK and the images are sharp, although the contrast is not optimal, and I now also have a camera bag! I have read on the net that the quality is equivalent to Tasco. So nothing professional, but you can still see stuff... I am still keeping my eyes open for something better though! Possibly with "fully multi-coated" lenses. :)

[OzStarGazer]

I bought a second pair of binoculars in an OP shop today. They work very well in daylight. The images were very clear.
They are like these http://www.ebay.com.au/itm/WATCHMAN-PRISMATIC-COATED-OPTICS-7-50-STRENGTH-BINOCULARS-TELESCOPE-/161440153999?pt=AU_Cameras_Telescop es_Binoculars&hash=item259695418f
... But I only payed $12.50, and for the price they are pretty good.
They also had a scope on sale, a "Precision" (brand) 8". It was cheap, but I would prefer a good brand for this kind of scope. Besides it was the only item in the store for which they said there was no warranty??? It was sold "as it is". (Usually they test items, but obviously they could not test it.) Now I also know for sure that I cannot move an 8" scope (I tried just to have an idea!). So obviously I would not have been able to do anything with it without a garden...