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10x50 Suggestions

Started by Larry Seguin, 12/03/2008 06:22AM
Posted 12/03/2008 06:22AM Opening Post
Hey all,
I'm looking for a recommendation. I've been using 7x50's on an HD-F2 mount for casual sky scans, but thought a smaller exit pupil might be beneficial. Can anyone point me to an inexpensive but decent set of 10x50's for nighttime use? For that matter, does the move to a 5 mm exit pupil really offer any advantages, or should I just stand pat? Thanks for any help you can offer!
Posted 12/03/2008 03:39PM #1
These Chinese binos and similar models sold
elsewhere are very nice for the money. A
little heavy for hand-held, but nice on a mount.
http://www.bigbinoculars.com/ultra50.htm
http://www.telescope.com/control/product/~category_id=binocular_standard/~pcategory=binoculars/~product_id=09544

Whether 5mm is better is much a personal issue.
If the outer 2 of 3 mm of your eye pupil has
bad aberrations due to advancing age, then
4mm or 5mm will be much sharper than 7mm pupil.
Posted 12/03/2008 10:07PM #2
Larry,
I too have a 7x50 and love it. But my 10x50 goes considerably deeper. With a 10x50, you will be increasing the effective aperture to a true 50mm (assuming your eyes, like mine, don't actually open up to 7.1mm), so stars will be brighter. The extra magnification alone will increase the visibility of objects significantly, separate tightly packed stars in clusters, and split closer double stars. And, as you understand, you will be seeing all this against a darker sky background, and with improved sharpness, since the smaller pupil will not aggravate your astigmatism as much.

My greatest objection to the 10x50 is that 10x is too hard to hold steady unsupported and really get much out of the view. But you already get the idea, and mount your 7x50.

I'm not sure how much you want to spend. Over on the Cloudy Nights Bino forum, the most popular $150-ish 10x50s are the Pentax (narrow field, but sharp to the edge), and Nikon Action Extreme (wide field, but soft edges). Both are said to be good quality optically and mechanically.
Ron