Optimal Binoculars For Pinpointing Galaxies?

[doubledipsoon]

I've recently gotten the Astronomy Bug and have been viewing the black California sky for many nights in a row. I have a old pair of Bushnell binoculars that are out of collimation, so have been using one eye to locate my new obsession- galaxies. Can anyone suggest the optimal binoculars for locating deep space objects like M-33, M-81, and M-101? I have found M-31 and M-33, but I need some recommendations for the proper "magnification" and "lens size", ala "7 X 50" ie. I've heard that it's best to keep the magnification low (7 or 10) and maximize the lense diameter for max light gathering. Does anyone have experience with bringing in these "smudgy" galaxies into a fuller view? Then I can point the view-finder of my Orion 5 inch reflector at that area for an easier viewing, Thanks and look forward to your responses.

[AstroJOE]

A decent pair of 8x40 or 10x50 if your doing handheld bino astronomy is arguably the most popular choice that tends to come up or something a bit larger like a 15x70 or 20x80 if you're going to be mounting them. I'm not sure thre is an 'optimum' size I guess it comes down to personal preference and the quality of the ones you buy. Bigger apeture will gather more light but you may get more regular use from the smaller ones. Make sure you go BAK-4 ones whichever size you opt for.

[Charic]

doubledipsoon........Hi, I purchased some Bresser Hunter 7x50's some 18 Years ago specifically to get the widest exit pupil, and I still love them today. Their nice and bright and take in whole vistas of the sky. I've also owned Helios 'Stellar 20x80's They were heavy, used mainly for Daylight reconnaissance? I saw jupiter with them, but unless you leant against the wall or tripod mount, the image was all over the place. due to the weight and high magnification. They were only really good for single small targets. I bought them new with an accessory pair of pocket binoculars, simply because I was at the right time and place. They were mis-priced by under £100 so I bought them there and then. I did sell them for a lot more when I came to move them on. I was`nt so deeply involved with astronomy at the time. Now anyone over 40 may not get the best out of a 7x50, but I still like mine. If I were to purchase again, It would be another  7x50 with BAK4 prisms or a 20x60 binocular?

[YouCannotBeSirius]

I use Olympus 10x40 binoculars which were about £54 on Amazon, they're big but not to heavy at all and I don't require a tripod for good, steady or prolonged viewing. I can easily locate and view M31 with them and I use them to locate things whilst using my telescope too. They offer good views of other DSO's like M42 and M45 but I haven't specifically seen other galaxies with them (though admittedly I haven't tried to) yet and I live in a location where I can fairly often find M31 with the naked eye.

[acey]

10x50 binoculars are great for galaxy viewing at a dark site - my first view of M104 was with those, as well as my first view of M33, plus numerous star clusters. For hand-held binoculars (without image stabilization) I wouldn't go above x15. The "optimal" exit pupil for night-time viewing seems from various people's experience to be about 3mm, which you would get with 20x60 bins, but in that case you would really want a mount for them. I have 9x63 and 15x70 as well as 10x50 bins, and personally I like the 15x70 best, but the weight and image-shake would be too much for some. 10x50 strike me as the best compromise. Somebody (I can't remember who) proposed judging astronomical binoculars by multiplying the numbers, i.e. 10x50 = 500, with higher being better, so 9x63 = 567 scores a bit better on that scale, though I find anything less than x10 generally too low to give interesting views. With 10x50 I could see the elongated shape of M104.

Edit: the product rule (termed "visibility factor") was first proposed by Roy Bishop, while another idea (due to Alan Adler) is to take magnification times the square root of lens diameter. This article explains and compares the two ways, and judges Adler's to be best:

http://www.garyseronik.com/?q=node/16

Adler's rule would give a rating of 70.7 for 10x50 bins. Interestingly, it gives roughly equal rating for 15x70 and 18x50 bins (125.5 and 127.3 respectively). Moreover, 18x50 bins would give the "optimal" exit pupil of 2.8mm. Image shake would potentially be an issue with 18x50, but this might be off-set by lighter weight compared to 15x70. So if you can find a pair of 18x50s then this might be what to go for. In fact Canon make an image stabilized 15x80 binocular, and it sounds like this might be the ideal instrument if you can afford the $1500 price tag.

[doubledipsoon]

A special thanks to all you chaps back in the UK for all your replies- Hey, I really appreciate the info. I think a good compromise (and it's ALWAYS a compromise) would be a 12 X 60 pair of Celestron Skymasters with "BAK-4" lenses, as some of you suggested. ...............The only thing keeping me from buying a pair right now is their relatively cheap price off Ebay. They only go for $50-$70. Can I expect any significant sharpness/clarity issues with such an inexpensive pair?  

[Charic]

US $32.oo here. Got to be worth a chance, Used, but informant says no defects?

http://http://www.ebay.com/itm/Celestron-SkyMaster-12x60-Binoculars-/121244774537?pt=Binocular&hash=item1c3ac07089

[doubledipsoon]

After brainstorming on which binoculars would be most advantageous for spotting "galactic smudges" in the sky, I have chosen the Celestron 12 X 70 Skymaster. It's all about maximizing aperature  (70 mm) with minimal magnification. This should be an improvement over my Bushnell 10 X 50 binoculars which are minimally out of collimation, as I have to use one eye to view the object......So far I have identified M 33 (other than the obvious larger M31). Next galaxies will be the triplet, M 65/66/NGC3628, which is (from what I've read, an easy "smudge" to locate with binoculars. It's in Leo, so it's a 2-3 am adventure for us crazies here in California. After that it's the Big Dipper galaxies- M 51, M 101, and M 81/82. So many galaxies- so little time.

[Charic]

doubledipsoon........Hi, Oops! I've just noticed the error in the link above for the Celestron Skymaster 12x60 binoculars  that went for US$32.oo    http://http://www.eb...=item1c3ac07089  It was cut and paste, so not sure how the link was damaged. Glad your happy though with what you purchased. clear skies.