What size binoculars do you like?

My favorite binoculars are my Fujinon FMT-SX 7x50's.  The field is generous at 7.5 degrees.  I do only a few binocular variables: Rho CAS, R SCT, W ORI, P CYG and others due to bright skies here in northern Houston.  Kevin  - PKV

I use my 8x40 Helios Naturesport most. It wasn't expensive and has a 8.2° wide angle. I use a handy monopod with my 10x50, a parallelogram mount with my 20x80 and a tripod for my 25x100. The bigger the bino, the less I use it! A 8x40 is just "fast", to make quick observations between the clouds or in the summer when it's dark, late in the evening.

When I was observing, I used three different binoculars, all to good effect. A pair of 7X50 Sears binoculars got me started, but I upgraded to a larger binocular, 9X63, and used those for a number of years and loved them. When the 9X63  pair was stolen, the insurance company replaced them with a pair of Nikon 10X70's which are good, but heavier. I can sympathize with your problems hand holding anything much larger than the 7X50's.

Back to the 9X63's which I consider the ideal for vsoing. During WWII, the need existed for binoculars with larger apertures to be used by bombadiers on bombing missions. Bausch & Lomb, who manufactured large numbers of the 7X50's for other military applications, produced the 9X63 by screwing extension tubes into their usual 7X50 units in place of the 50mm objectives, and added the 63mm objectives at the slightly longer focal length. The combination produces the same exit pupil, best for dark night skies but perhaps not so great in urban or nearby suburban areas. The weight of binoculars is for the most part in the prisms and focusing mechanism, so the change in objective diameter had very little effect on the overall weight or balance of the binoculars. You will occassionally see a pair of the WWII B&L 9X63's for sale and if you can find those I highly recommend them for vsoing.

I've purchased a 20x60B russian (Tento) binoculars around 20 years ago, when it was very popular among Hungarian observers. This is perfect for variable stars. I use it without tripod. Nowadays several of my friends who observe variables use 15x70B (Skywatcher?). It is much lighter then the old russian 20x60B, but smaller magnification.

My 20x60B is perfect for variables in the range of 7-10th magnitude (even from the light polluted Budapest).

Hi, Chris,

I use 7x50 Pentax binoculars. Those are the only ones I own and I like them, they are luminous. In the best nights (like last night) I get to a limitting magnitude of 9.0 from the city. I don't have a mount, I always observe resting my arms on the arms of my lawn chair. I couldn't observe in any other way without a mount. I have tried 10x50s but I didn't like the darker background and the fact that I couldn't get the image steady due to the larger magnification. They are more comfortable to sweep Milky Way fields and general observing but didn't find it appealing for variable star observing.

Cheers,
Sebastian

Hi all, I like to use my astrophysics 15x70 binos, they are great quality but a little heavy to hand hold and are amazing for the brighter variables. Also sometimes I like to use mt 20x90's on my parrallelogram mount which doesn't take too much time to set up, on a good night they can get me down to magnitude 11.5

Nova patrol is my thing, but I find that although you can memomize starfields, I am thinking about going over to DSLR imaging instead, although with my binoculars, I love that 'live' view feeling.

Keith.

I enjoy my Orion 15x70 binoculars for visual variable star estimates, solar observing, lunar observing, and deep-sky observing.   I mount them on a Bogen tripod.  The entire setup is sturdy and quite portable.

Regards, Doug

I use Orion 10x50 binoculars but have a hard time holding them steady. I gave Canon 10x30 IS binoculars to my wife primarily for bird watching, and was amazed by how well the image stabilization works. I tried them on the stars and was equally impressed. The steady view goes along way towards making up for the lack of aperture. Has anyone had a chance to use larger Canon IS binoculars? Unfortunately they are very pricey.

As someone with a long, long history of employing binoculars for the observation of variable stars (and comets), particularly so in my early AAVSO years, I always highly preferred 10x50 WA binoculars. When I first moved to my rural home some 4 decades ago these binoculars were quite capable of allowing estimates as faint as the mid 11's without difficulty. Needless to say, urban sprawl since then has steadily reduced their ability and today my choice has become a pair of 15x70 binoculars, which I still generally hand hold during observing.

Early in my observing career with the AAVSO I was mentored by the organization's premier binocular observer, Edward Oravec. One especially valuable lesson he passed on to me was that the best choice in a pair of binoculars for variable star observing was one affording a 4mm or 5mm exit pupil, not one with 6-7mm. This, he pointed out, was particularly true in the case of urban and suburban observing situations, something that has today become almost universal for AAVSO observers. Ed's longtime choice in binoculars was a pair of 10x42's. With those he made more than 150,000 estimates.

Except in a truly dark location the pupil of the eye never fully opens beyond 5mm, or possibly 6mm in the case of the very young. For older observers like myself, even at a dark site the pupil likely never exceeds the former value when it is opened to its maximum. Obviously then, if the exit pupil of the binoculars is 7mm, and the opening of the eye only 5mm, then you are essentially reducing significantly the relative aperture of the instrument, wasting light and limiting your magnitude threshold. The sky background darkening effect with increasing magnification, along with the greater separation of the comp stars in congested fields, are also advantages not to be overlooked.

J.Bortle   (BRJ) 

My favorite binoculars for VSOing are my Orion 12x63's. They give a large enough FOV and I can still hand hold them and I gain about a magnitude over my 10x50's.

Rich Tyson (TYS)

I have used Canon 15x50IS binocs for years, both for VSO and general observing.  As John points out, exit pupil is important.  The exit pupil, 15x magnification, and 4.5 deg FOV make these binocs wonderful if you can afford them.  I sold my first pair to raise money for another project, but could never find less expensive binocs that I liked nearly as well so I ended up buying another pair and will never let them go.

If you can afford them, they're the bomb!

AstroFriends,

I prefer a 15x60 to offer a better contrast in cities with high light pollution. I do not use mount, only my arms. I use a 7x35 for stars brighter and larger fields.

João Marcos, Brasil

Similar to ajc, I like to use both 7x35 and 12x60.  My 7x35 shows a 9.3 degree field of view and easily reaches down to magnitude 6 or 7, depending on the skies.  The 12x60 is surprisingly lightweight and convenient, and easily shows much fainter stars (down to magnitude 9.9 on a couple of occasions under excellent skies).  While I have found 10x50 to be a decent compromise, I'm reminded of the advice about telescopes given to me years ago by a wise mentor:  "one is never enough."  I think the same might apply to binoculars, if they will be used often. 

10x50 of different makes.

I used a Chinese made 10x50 from 2012 'till 2014, when I got a USSR made Tento 10x50, with better focusing mechanism. Since 2018 I now use a Jenotem 10x50W during the warm season, and the Tento during the winter (I sold the Chinese one for a fraction of the price I paid for it - it was a pretty good binocular, and it was a pity to have it sit on my desk gathering dust).

When I'm ready to go to bed but I still have a few minutes, or when the sky clears up unexpectedly, I use a Japanese made Greenkat 12x50 or a '50s made Skybolt 10x50 (I know, too many 10x50s), depending which one happens to be next to my window.

I have only just started out observing variable stars and I have several pairs of binoculars but so far my go to pair for this are my BUSHNELL 10X50 Legacy WP Binoculars.

Whatever I can hold - usually 7 x 50. However, I have my Celestron 15x70 on a parallelogram mount and that works well.

Mike

Any thoughts on the best value for the price on a parallelogram binocular mount?  Or a good build-it-yourself plan?  Like Mike, I have a pair of 15x70 that I'd like to use more often.

Arne

I have been estimating variable stars for 20 years with 15 x 70 binoculars. They provide you a darker field from suburban skies compared with 10 x 50 ones and are manageable yet looking for distant comparisons dealing with brighter vars. Under a really clear sky thanks to siberian winds I got M33 from my windows , then they have the upper hand as deep sky companions too. When they have been suffering mechanically and optically I got a similar, unbranded 15 x 70 pair again. Someone can manage 20 x 80 binoculars, but given price and need for a tripod a short tube telescope 80 f/5 is a better option. I used to be a receiver, not a linebacker.

Hello! I use the Orion Paragon Plus Parallelogram mount and tripod as well. Mike

I love my Fujis 10x50: 6.5º of flat field and high contrast views. I use them on a camera tripod which makes a very neat rig for brighter VSO.

I was just thinking about this today.  I've been using a 10x50 Pentax on a Peterson mount.  (Which is a dream to use.  https://petersonengineering.com/binocular-mount/).

I like the 10x50 as it gets me a 5 mm exit pupil (I am never going to get suitably dark adapted for a 6-7 mm exit pupil where I live, if my eye pupuls will even open the wide anymore) and is decently lightweight.

Still, I keep wanting a bigger pair....and while a 15x70 doesn't seem that much heavier, I must remember that for any weight I must double it (to count for the counterweights on the mount).  Also, a 15x70 would give me an event smaller field of view and I find the 10x50 ~5 degree FOV just about perfect.  

Convinence is a huge factor for me.  If I went any larger than 10x50....I probably would observe less and that just isn't good.  :)

--Michael in Houston

Hi Michael,

re "wanting a bigger pair" (and weight) ... there is an alternative option to larger objective lens/more power and a heavier unit and that is binoculars that transmit more light thus brighter and able to see lower magnitude stars.  The issue is co$t as these are expen$ive.

I stumbled across my well hidden second ever binoculars the other day (my first was 7X35 Bushnell), 10X50 Minolta.  I had not picked these up in 45 years +.  When I went out in daytime, they actually looked pretty good but at night, it was as if the gods turned the lights off.  My 8X42s were far superior (and much brighter) to these 10X50s due to 45 year newer prisms, coatings and technology.  Likewise, I imagine the Zeiss 10X54 Victory HT (advertised as highest light transmission in industry) would allow magnitudes to be seen that many 12 power or greater binoculars can't reach due to technology (and thus co$t) differences.  If these 10X54 could be handheld vs using a tripod, that would be terrific. 

I did read that power is a more dominant factor than light gathering in being able to see faint stars but still, the difference high-end binoculars can make with best availalble light transmission in a relatively small/light unit could be ideal for those concerned (rightfully so) about weight of unit. 

Co$t of unit?  That's the real limiting factor.

From a heavily light polluted Orlando suburb, Bob SRGA.  Keep looking up!

You can go with 10x50 binoculars. Let me explain why I am saying this

Hi All,

I'll chime in on my nightly binocular use... 

I use Bresser 10x42mm binoculars nightly on bright variables, normally 5th magnitude or brighter. Then I switch over to Oberwerk 25x100's that get me to about 9th mag, and I also use Explore Scientific 125mm Bino's at 33x to get to 11th mag. I'm in Bortle 8/9 skies so difficult to go fainter with the binoculars I have.

I really enjoy brighter stars and visual observing, and I hand hold all the way to 25x, and it does not really affect the visual estimate. In some cases not have rock steady views can make it easier for me to estimate the magnitude. I do this regularly with the 25x100's. I have a great outdoor chair that can swivel 360 degrees, my neck/head can lean back on the top of the chair, and my arms are firm on the arm rests. That gives great stability with those big binoculars. I would not use them hand held for any other type of observing, not even planetary, as you really need the steadiness of a tripod to see the detail. But a slightly out of focus variable star, to help estimate the magnitude, with a little instability, does not hurt the estimation.

I also have various other bino's and regularly use 10x50 and 20x80 depending on time of year and variable magnitude.

Andrew Corkill (CANG)

www.riverstarobservatory.com