Both will be great for astronomy.

Celestron SkyMaster DX 8x56 Binocular

If you're over 25, either has the disadvantage of having more exit pupils than your eyes can probably use. As a result, they will be heavier than they should be for the quality of the views you'll get. After 25 or so, most people's pupils only dilate to 4 or 5 mm even in total darkness rather than the 7mm these provide for. 10x50s or 8x40s, or even 7x35s, might be better for users over 25 or those observing from a light-polluted urban environment. For older folks, for example, 7x50s will effectively just be a hefty and bulky pair of 7x35s, and 8x56s will function like an unnecessarily heavy, bulky pair of 8x40s. That said, 7x50s will be more easily hand-holdable, although the difference isn't huge. The image will be slightly bigger with the 8x56s. As the video mentions, the eyepieces on 8x56 are more likely to be suitable for those who wear glasses. Unless you're pretty young or one of those rare older people with exceptionally supple pupils, you would probably be better off with 10x50s, 8x40s, or 8x42s than with either 7x50s or 8x56s.

@@RobertEWaters I have read conflicting information on the pupils issue, its a gradual process. From 18 to the 40s most people pupils dilate to 7mm, but they on the average people lose 1mm per decade after your 40s, so a person over 60 will get maximun 5mm pupils. So for them a 7x35 will be as bright as a 7x50, a 8x42 as bright as a 8x56, and a 10x50 as bright as a 10x70. Yet bigger pupils do have another use, like using the binoculars from a moving plataform, one of the reasons why the military and sailors love the 7x50. With the moving vehicle adding to the movement of your hands, bigger exit pupils are easier to aling with your smaller 4mm daylight eye puplis. For astronomy 10x50 seems the secure choice with better constrast and power. But i do like the 7x50 for handheld stargazing because it has less shakier images due to the smaller agumentation, and the larger pupils do help with the shakes. I got a monopod to use with the 10x50s. Yes, a 7x50 will waste some light in my 50 something eyes, but i do not care, light comes free and I got those binos (1990s Steiners) since I had younger eyes. PD. I got 10X50 Nikon Aculons to test the idea of a 10X50. So far so good, also got a second hand battered up Fujinon FMTR SX 7X50, they are amazing. Now I need a Fuji in 10X50 to get seal the collection, and retire the others from the astronomy job.

Right now yes... and saldy the 7x35 and 7x 42 are even harder and harder to get too.

Glad we could help! Thank you for watching.

But be careful. If you're over 25 you probably won't be able to make use of the 7mm exit pupil because your own pupils will only dilate to 5mm or so in total darkness.

@@RobertEWaters Thanks I want with the Nikons 10x50 Extreme ATB no regrets :-)

@@RoigRivera Excellent choice!

Fixed focus binos work the same as focusable binoculars. Only difference is the fixed focus. Terms as „Sports Autofocus“ are just nifty marketing. Fixed focus is advisable for low light environments like hunting at dusk and dawn since it is more difficult to get a good focus in these environments. Fixed focus binos are also useful for marine optics since it is easier to waterproof them and you dont need to refocus them often anyway.

@@fd1053 Also Fixed focus is used in high end astronomy binoculars too. Is Simpler mechanically, so is cheaper to make, and more abuse proof, so marine and military binoculars often get Independent eye fixed focus, IF. Also since sailors, miltarymen and astronomers are not interested in observing things like birds or butterflies at close range, like nature watchers do, with iF once you get the right, 20 meters to infinte focus for your eyes, you leave the binoculars alone and they will be always in focus.

Unless you're under 25, avoid both. The pupils of your eyes won't dilate enough to use a 7mm exit pupil. Get a pair of 10x50s or 8x40s. Their 5 mm exit pupil will probably be all your eyes can use.

7x 50 for better field of view

@@RobertEWaters I always had very large pupils. Any time I went to have my eyes checked, the opticians always remarked how big they were. I'm in my 50s now and my pupils in dim light (still not fully relaxed) are 6mm. So, some people are outliers. But what you say is, in general, correct. Also, when younger I had very large focus accommodation ability. When I was a kid I could focus on the end of my nose (and my nose isn't big!). When I was in my 20s I had a pair of Fujinon 10x50s. These binos are supposed to have a close focus distance of about 20 meters, but because of my large focus accommodation ability I could comfortably use the binos to look at objects from infinity all the way down to about 2 meters away without ever having to touch the focus on the binos. I loved those binos, although they broke after about 8 years due to constant use and abuse.

If you're over 25, you probably won't be able to take advantage of their low-light performance because the pupils of your eyes will likely only dilate to 4 to 5mm even in total darkness. You'd be better off with 7x35s, 8x40s, or 10x50s. Generally, porros are better for astronomy.

Human pupils go from 4mm in strong daylight to 7mm at night in a younger person. But as you get older you do lose night vision, and the average 60 years old pupils will be like 5mm max at night. So older people do not get the same brightness from larger exit pupils than younger eyes do. For a older person a 7x35 would be as bright as 7x50, a 8x42 as bright as a 8x56, and a 10x50 as bight as a 10x70. But in daylight well everyone will get 4mm pupils. So your 8X56 will turn into 8X32s and your 10X56 will become 10X42s in daylight. Im settled into 10x42 at day and 7x50s at night but the 10X50s are coming soon. 8X40 or 42 is probably the best general use size. You get 5mm pupils at night and is not too big to hang around. Not too dark for a younger person and without of the size and weight penalties of larger objetive lenses a older person might no find usefull.

After explaing the puplis issue, well the answer about there is a disadvantage of using a 7x50 or a 8x56 in broad daylight.. The answer is no. Only that since your pupils will be smaller during the day you will be using a 7X28 or a 8X32 but a very bulky one! Got a 10X50 Nikon Aculons to test the idea of a 10X50 at night for fifty something persons. I still found then darker than my Steiner MM and my Fuji FMTR SX 7X50s. Maybe is the cheaper glass plus the 5mm pupils. But the difference in constrast at night makes a huge difference. Time to start saving for a FMT SX2 10X50. Im keeping my 7x50s, they are comfy for long hand held view sessions and to see whole fields of stars, but for the Moon, planets and to see the stars among city lights the 10X50 are better.

@@ricardosoto5770 I appreciate your analysis and insight. Thank You!

@@ricardosoto5770 I have military issued Fujinon 7x50 M-22s. Besides the laser filters I noticed the bluish tint in the lenses. I was disappointed at first because they didn’t seem very bright but came to understand and appreciate the tint reducing the glare of the ocean, snow and sun when needed.

No. Steiner does not comes with a tripod adapter, it will be a bit of a overkill to use them as a fixed target spoters, a spotting scope is better.Also since they are Independent Eye Focus, they cannot be used for pistol shooting. Get cheap 10x28s for that. But, but, for sniping/countersniping, the 8X56s might have and edge, the Major John L Plaster, in his book The Ultimate Sniper, called the Steiner 8X56 Nighthunter (sold as Shadowquest in the USA) the best countersniper binoculars he has ever tested, due to the ability to fish out well camouflaged snipers fron their hides. The books chapter on binoculars and spotting scopes is a must read.