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on 9 December 2009
This posting begins with a discussion of some core information about binoculars for astronomical viewing that should help potential purchasers make a more informed purchase decision.

If you have other viewing objectives than astronomical objects, or are already familiar with binocular specifications, you may want to stop here or just read the latter part of this review before going on to other postings; otherwise, read-on.

There are two main styles of "true" binoculars. Here, binoculars that do not use prisms such as opera glasses, are not discussed further. Most binoculars use one of two type prisms, either roof prisms or Porro prisms. Roof prisms are more modern and have a straight through appearance, i.e., the binocular cylinders form straight tubes. Porro prism binoculars (named after Ignazio Porro) have a tell-tale right angle bend. These usually are manufactured with two prism on each side of the binoculars, i.e., double Porro prisms. Although considerably larger in size, because of their improved optical qualities Porro prism binoculars, such as the model reviewed here, are preferred over roof prism binoculars for astronomical viewing.

Another important aspect of binoculars is the size of their exit pupil. Younger folks have pupils that can open, dilate, to a maximum size of slightly over 7mm. However, as one gets older the size of this window into the eye reduces. Over the age of thirty most folks have a reduction in their dark adapted pupil size of approximately 1mm every 20 years. The exit pupils for a pair of binoculars should ideally approximate the entry pupil of the observer's eye. Although some studies suggest an even smaller exit pupil size, see below. The size of a binoculars' exit pupil is found by dividing aperture by magnification. For example, common 7 x 50 binoculars (7 power by 50mm) have an exit pupil of approximately 7.14mm. In practice, this exit pupil size is larger than many adult's dark-adapted pupil size, particularly when some extraneous light is also present. In most viewing environments such as in or near a city such extraneous "light pollution" is almost always present. In addition, the periphery of the eye's lens exhibits some inherent optical degradation. Thus, an exit pupil size around 5mm may be preferred, although some experimental evidence suggests an exit pupil even less than 4mm may be most appropriate. These 15 x 70mm binoculars have an exit pupil of approximately 4.7mm resulting in more of the light exiting the lenses entering the eye than might occur with e.g., 7 x 50mm binoculars.

One of the most important considerations when choosing binoculars is their light gathering ability. Binoculars are essentially "light buckets". The human eye at its widest has a 7mm plus entry window. The 70mm objective lenses here have over 50 times the light gathering area of the human eye. Another factor affecting the light transmitted by binoculars are the materials used in their lenses and lens coatings. The least expensive binoculars have uncoated lenses or single coated lenses. Multi-coated binocular lenses and BaK-4, barium crown glass prisms, as in these Celestrons, are typically more expensive but improve light transmission resulting in sharper and brighter images.

The best eye relief, i.e., the distance your eyes needs to be behind the exit pupil of a binocular to see the full exit image is probably between 15mm and 20mm. These binoculars provide 18mm and additionally come with rubber eyecups. Thus, I've been able to use these both with and without glasses. I use lightly tinted sunglasses when viewing the moon to see more detail. In this case I leave the eyecups raised. When viewing without glasses I leave the eyecups down.

In use, I've found the images sharp and with adequate contrast to enjoy star clusters, the moon and planets. This pair's primary negative is its size and weight. These binoculars are really big. Owing both to their size and weight and as well as the relatively high magnification they are not comfortable to use hand-held for any but the shortest period of time. Because of their magnification, the slightest shake moves the astronomical object out of the field of view. Fortunately, they come with a tripod adapter. However, for some the need to use a tripod may defeat the value of having a "portable" pair of hand-held binoculars. For these observer's a smaller 50mm binocular is more appropriate. A minor problem is the carrying case, mine arrive with missed stitching on about a 1" section of a vertical seam, letting light through and possibly rain. The case is also a bit tight making it more difficult to easily insert and remove the binoculars, a better degree of quality control for the case, and a slightly larger size would seem more appropriate. Simply holding the case to the light and looking inward will reveal any stitching missed.

However, even recognizing that these binoculars cannot be hand-held for any extended period, they are probably one of the best choices for astronomical observers who need relative portability compared to a probably more cumbersome and expensive telescope. Perhaps surprisingly, they are also an extremely useful adjunct for those who use telescopes.

In summary, these binoculars allow for considerable additional exploration of astronomical objects compared to the naked eye. However, a tripod is required for any extended observations. Highly recommended.
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on 24 April 2017
Good for the money.
Despite their very large size l do not find them heavy which surprised me.
They are big though 13" x 8.5" 33cm x 22cm.
They come with lens caps and a bag.
They are well built and seem sturdy.
The downside is the cap covering the eye pieces does not fit very well at all, the end caps fit ok but l have found they do tend to come off now and then.
The worse thing is the bag, it is thin and floppy! it offers very little in the way of protection and worse the bit of hook and loop is barely enough to keep it in the bag.
The optics are quite good given the price and it is very easy to mount on a tripod, l was confused as to how this was possible but when it arrived l saw that the big sliver knob thing, well lets see if l can explain, the silver knob you can see in the photo is for tightening a bar that extends down between the binoculars to a standard fitting for a tripod shoe, if thats the right word? so you dont have to buy the adapter thing shown in the section frequently bought together. l will see if l can add a photo.
To sum up these are great for the money and worth buying just to see the moon! they are good for night time as the big front lenses let in a good amount of light, they are also as good in the day for looking at the landscape. Used with a tripod gives even better and relaxed viewing.
The photo shows the binoculars viewed from the front with the tripod shoe fitted, it just screws on and there is a locking ring for easier tightening, the silver knob allows the mount to be adjusted along the silver bar to find the point of balance when used on a tripod, thats what l use it for. Hope this is of help.
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on 8 April 2017
These binoculars let in a huge amount of light helping you see stars easily. I haven't used them in anger much yet but have been great to pick up and have a look at the moon and other celestial objects. So far I've seen the Orion Nebula, the Pleiades, the odd planet, and the moon. Been waiting for a nice clear night to try and see more.

These are my 3rd set of these unfortunately. The focus adjustment was damaged on my first two sets but amazon sent replacements very speedily. Checks yours when they arrive. I would have hoped the build quality was better but I may have just been unlucky.

The plastic tripod mount is very wobbly, best to try and buy a metal one, although the metal one will still wobble a little it is a lot lot better.

The minimum focus is probably around 40m so no great for looking at anything in most back gardens, or your next door neighbour.

Had a look through them this evening and observed Jupiter and its moons and an almost full moon. Took some pictures on iPhone 7+ through the bins at 1x and 2x on the iPhone to give a rough idea of what you can see. The 2x pictures are more likely what your eye will see. They are wobbly and a little burry but it was the best I could do. The clarity through the bins is great but the iPhone pictures are just to show the magnification so ignore the quality and the flares from a nearby street lights. I have been observing the moons moving around Jupiter over the last few nights and it is amazing to see them change every night.

I did a little bit of research before buying these and the Amazon reviews for these really helped as I was after a pair just for astronomy.
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on 7 November 2017
I bought these for casual astronomical observation - something to keep in the boot of the car - and for that purpose they fit the bill nicely, but it's important to be realistic about the mechanical and optical quality you're going to be getting for less than £100. There are better options available if your budget can stretch to £150-200.

1) 25x magnification and 70mm objective will give you entertaining views of the moon and other prominent solar system objects on clear nights. Just remember that everything else will still be tiny dots of light - these are only binoculars.
2) They are just about light enough to be hand held, but you'll need to use a tripod for any extended viewing. A cheap plastic tripod mount is supplied with the package.

1) The casing is rubberised for good grip but offers minimal shock protection so you wouldn't want to drop them.
2) The supplied tripod mount is plastic and offers minimal torsional rigidity (you'll get a lot of side-to-side wobbling if you touch the binoculars while viewing). You may want to invest in a more robust tripod mount like Opticron Binocular Tripod Mount for Binoculars +50mm OG.
3) The supplied carry case and strap are cheap and nasty nylon and offer zero protection. Keep the bubble wrap.
4) They are supposedly 'water resistant' but certainly not shockproof, waterproof or fog proof.
5) You will notice some chromatic aberration or 'colour fringing', particularly on full moons, but probably not enough to spoil the experience at this price range.
6) You will get pot luck with the collimation (the mechanical alignment of the internal optics). My pair weren't too bad but other reviewers have reported very poor collimation out of the box. While the supplied manual offers no guidance whatsoever, it is possible to find instruction videos on YouTube (Google "Celestron binocular collimation") which identify the small grub screws which can be used to adjust the collimation - they're actually just underneath the rubber grips but can be accessed by gently prising away the edge of the grips (at your own risk). You may be lucky enough to have a friendly local retailer that will do this for you.
7) I suspect the 'Limited lifetime warranty' might be extremely difficult to invoke in practice after a year or more, particularly via cut-price Amazon suppliers. Also, according to the manual supplied with my pair the warranty only applies in USA and Canada anyway.
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on 5 November 2015
Despite the size of these - I didnt see much. The tiny stars in the sky - continue to look like 'tiny stars in the sky'.

You cant see craters on the moon despite others reviews.
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on 9 November 2016
Bought last night @18:35. Postman brought to me this morning (Left them in the shed), all the way up here in the mountains of North Wales.
Packed well enough. As they'd been left in the shed on this cold morning they didn't need to acclimatise so tried them out like an excited kid, I'm bald and certainly not a kid, well not by age anyhow.
These are really good. I needed to adjust the right eye as it was wound all the way up but that is not important. There's a lot of adjusting there for folk that need to balance the focus for their needs. Once the right eye is set it is rock solid and doesn't move if I wedge the bins on my face. The focus wheel is very resistive and is great for fine control. I'm left handed and I've found that I gold the right side at the far end of the bins and my left hand is by the focus wheel. Works well to counteract the slight vibrations I can't quite eliminate from my hands. Won't be a problem when I look to the night skies as once the focus is set it won't need adjusting and I'll hold the far ends of the bins.
There is a lot of adjustment available for the width seperating your eyes and is resistive so fine adjustment is a doddle, once it's set it too is rock solid. My 6 year old daughter can use them when set to the narrowest. We rested them on a convenient fence and she scanned the hills and skys that make up our view. She is blown away, as am I.
From the house we are lucky to be able to see for around 30 miles and the view is filled with rolling hills, mountaind (Snowden, Siabod, Tryfan The Arans, Berwyns etc). These distant, usually wet hills are amazing in these. Birds look fantastic as do distant running horses.
They are not perfect though. Looking at the jagged bluffs in the distant and the edges are rainbow edged (is this chromatic aberation?). White birds on a brilliant white cloud are the same. BUT I was lucky to have 2 swans fly in to my field of view and it was wonderful to watch them with the green hill behind them. The 3D effect (caused by focusing at a certain point) is awesome, like paralax scrolling. Lovely detail and crystal clear with excellent detail for things miles or hundreds of metres away.

Earlier this year I bought Olympus DPS-1 8x40 for my in-laws. These are used for bird spotting and are very very good. Have tried them for astronomy but a little to restricted for me. Also if held against the face too hard then the right eyeiece can slide from the focus position it was in. Not a very fair comparison as they are more of a premium brand and way smaller BUT compare I will and these are better in most ways, clearer, more to see because of the magnification and bigger lense, more resistive focus (I prefer this as it's easier for tiny adjustment). BUT are a bit heavier and they don't have the rainbow edge fringing as much as these (it is there though). They are much more portable too. These celestions have a much longer body after the lense so in the rain earlier no rain got to the lense due to this overhang but does on the smaller binoculars.
I bought these Celestrons for astronomy as I don't have time to get out my telescope much these days (Tal-1). I know these binoculars can't replace my telescope. It is an amazing device and I have huge open skies with no light pollution but I work shifts, got 2 young kids one thing I lack is time. With these I'll just need to pop out in a thick coat and go for it. I will update my review after a clear night allows me a look at the skies.
I don't know the technical terms for much regarding binoculars, have read loads of positive and negative reviews and I'm very glad I took a gamble on these beasts. The rubberised body is nice to hold and goes right over the big ends and back up towards the lense too. The strap is crap, digs in my neck. The eyepiece cap is tethered but the other 2.
For me there are as yet no negatives.

5 people have used these and had no problems, all impressed but then one other friend used them and could not gat a single image, constantly seeing double. We have used them since and nobody else sees double, strange.

XXX UPDATE XXX I can now scan the skies directly above using these. Almost impossible with my telescope. I found a big white galaxy, really clear, some awesome star clusters but had no means of identifying anything. Awesome binoculars.
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on 14 October 2016
I will caveat my five stars to say that I think these bins deserve that rating in the £50-£250.00 price bracket.

When I choose bins I rarely go for anything where the focus doesn't divide into the object lens size by at least five times (just my estimate). These are 15 x 70, so just under that BUT the exit pupil is large, so you get lots of light through. They are never going to be as bright as my 7x42 bushnell of course, but nor will my bushnell get the distant these give! All the same, at 15 x 70 the image is still nice and clear. I can't really see why you would go for 20x or more because of the loss of light, unless you get an object lens of 100 or more, which would be really big!

Anyway, I bought mine mostly for watching the killer whales and harbour porpoise that swim along the coast near my house, and maybe to see what more distant neighbours are up to, sorry, I mean stars and stuff. Trying them today, they have been perfect. I have actually NOT tried these for astronomy as yet, but I'm sure I will.

Weight wise, they are heavy and they are big in length, the main body is pretty much in keeping with a 10x50 pair of traditional bins. Though, using them mostly for watching sea life and birds means that I scan the ocean with my eyes and then use these to focus in on detail. If I was to keep them at eye level all the time, it would be a real test of strength! So I've no doubt I will look at a tripod.

So Tripod? Yes, if you are going to use these for extensive periods of time, and something good, not your standard £9.99 aldi type. The adapter that comes with it, as already been said by others, is pointless. Get another one, they are pretty cheap anyway. I really wish they would just drop that in the package and improve the case, or use the saving on some other area of the bins.

Technically, I guess I'm lucky, I have had NO collimation issues from the box, they were perfectly aligned. Overland viewing gives no fringe, not sure with astronomy stuff as that is not really my field.

Focusing is a little stiff at the moment, though I'm used to that with new bins, so I expect they will loosen up.

The carrying case is pretty basic, no, the carrying case is very basic and will offer no protection from bumps whatsoever. I guess when you make a decent pair of bins, you have to cut costs elsewhere; celestron have done the cost cutting with a naff neck strap, near to useless carry case and a very useless tripod adapter. BUT don't let that put you off. The binoculars themselves are excellent.

So in short, large, but bright, and a great price for a decent set of binoculars. Very pleased with the purchase.
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on 3 October 2015
I purchased these binoculars specifically to view the moon, as I was travelling it was a couple of weeks before being able to test them - when I did, they are so badly out of collimation there are 2 completely separate images and consequently they are completely useless. I have just checked the return process and discovered I am just 2 days too late. Very poor show for the product and poor show for Amazon having such a short return window. This has been a complete waste of money and my first ever bad review on Amazon.
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on 30 December 2017
I was looking for a good set of binoculars that I could use purely for astronomy, the Celestron Skymaster Binoculars are good quality and if you are wise you can shop around and get them at a reasonable price. I first researched many astronomy magazines and watched a few You-Tube videos to ensure I purchased my first dedicated astronomy binoculars. I purchased the Celestron Skymaster 20 X 80 set of Binoculars and they are incredibly powerful and perfect for observing the Moon (close up and personal on a clear cold night) and some star formations, they are also good for viewing high flying aircraft on a clear day as long as you have a good solid tripod to hold them up as these are far too heavy to be held up in your hands for longer than a few minutes. My best advice is research before you purchase, buy the best you can afford and ensure that you buy the right size and support so that you can use them at any time of the day and night; if you buy these 20 X80 Binoculars, then make sure you also have a good solid tripod with moveable head to hold them up because you will very soon realise they are very heavy to lift up for more than a few minutes without your hands and arms becoming very tired. I love my new binoculars and so does my family.
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on 23 December 2017
For some unaccountable reason the reviews are all jumbled up, so different sizes and powers appear under this heading, making the reviews less useful than they could be. The 80mm binoculars will be a lot heavier.

Also remember there are three versions of the Celestron 15 * 70. This version is around £70, the Skymaster Pro is around £200 and the Echelon is around £800. You get what you pay for. If you really need the best binocular at this size then you can easily spend well over £1000 on some makes. Then ask yourself why. For that price a good astronomical or bird spotting scope might be a better bet.

I have found that these give a decent magnification and bright image at night, but are not a lot of fun during the day because of colour fringing and a lot of unwanted reflection. However I bought them specifically for looking at constellations. I don't expect to see any planet detail through these. But the bright image will show many more stars, and a wider field of view. I don't plan to use a tripod, but expect to sit in a folding chair to aid stability.

They are cheap and are good enough for the purpose for which I require them. If you want this or greater degree of magnification in day time use bite the bullet and spend a lot more. And consider a spotting scope as an alternative.

Definitely don't buy them as general purpose binoculars.
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