Telescope Reviews: Nikon 18x70 Astroluxe Choice again

That's a fine offer Wes, but you'll have to pry my 15X80 Steiner's from my cold dead hands! I went observing Friday on the packed snow with the Mortar and my Steiners; aperture Rules. The 18X70 Nikons have about the same TFoV as my Steiners, and more power, but also more weight - these weigh 58oz, not 5 lbs, yet they're still waterproof, nitrogen purged and solidly built. For night use the lower magnification comes in handy keeping my favorites in view. The lighter weight of the Steiners is less tiresome when held by hand and they came with a tripod adapter for when I acquire one. These are actually model 416 Military which includes the compass/rangefinder - very handy when I'm storm spotting, or identifying aircraft - such as the space shuttle as it passed over Nebraska.

I admit, the compass intrudes into the lower third of the right eyepiece, but I'm left eye dominant anyway - it doesn't bother me at all in dark skies. Yes, there is modest CA, as well as a little astigmatism, but as Pedro explained, there is a simple cure, install a field stop to lengthen the f/ratio. It was fairly obvious at night at the edge of the field, but not not objectionable for such fast optics. If I were more of a true binocular afficianado, I would have been looking for 20X80s with at least a 500mm Fl weighing in at over 8 lbs. I'm used to testing my optics at night. I hadn't noticed it much during the day - with a 375mm FL and ~4 deg TFoV I wasn't expecting perfection. The Steiners have ~60 deg AF @ f/4.7 vs 72 deg AF @ f/4 for the 18X70 Nikons - no doubt why Nikon pays such special attention to the coatings, they Need to, for both the objectives And the eyepieces for such quality performance. The icing on the cake, for me, was the price - $400 Less than the Nikons. These are a discontinued model, the compass/rangefinder uses passive illumination instead of the active illumination of the new version. For some reason, I seem to have this propensity for accumulating red flashlights; I didn't feel it necessary to pay for the latest "feature".

However, for daytime use, I tend to agree with Rick. Magnification rules the daytime, within the focal distance, and the ability to fit within the FOV with a large sweet spot. It should be easier to maintain a longer f/ratio, preserving the hand held ease of use, yet reducing the CA and astigmatism, with a good IS binocular. Extra magnification also helps me spot smaller, yet brighter targets with my 12X50s at least as well, if not better, as a friend's 10X60s. 18X50s would be my preference for daytime use; lighter, longer f/ratio, probably less CA and astigmatism, with my 12X50s as a waterproof back-up. For the short term, my choice was aperture over magnification. The improvements in IS tech appear to be advancing faster than the long proven compromises with more standard binoculars. Look how much the prisms, servos, electronics, magnification, multi axis control, weatherproofing, and battery life have improved since IS binos were first introduced. I needed aperture more now, I can grab improved IS tech later; water proof please, with fewer dead batteries. Buy for what you need most NOW, NOT 30 years from now. I'm not waiting for the UNOPTOCULAR.

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John, "Have eyepiece - will travel!"

8" f/5 Dob w/2.14" sec in a 12" alum tube "The Mortar" - w/PCorr 2.16° TFoV @ ~32.5X 70+% illum *Yes!*
24Pan, 5-8 SW, 3 Faworskis (16.8, 10.5, & 7mm), TMB 3.2mm, Hyp 36mm Aspheric, 20T5, & 14ES100
Other 2": Paracorr (Green Parrot), 2X PowerMate, Antares 1.6X Barlow, Astronomik Hß, (older) Lumicon UHC & OIII
60mm $50 Walmart Special in training - aka "Backpack Observatory"
Binoculars: Minolta Activa 12x50s & Steiner 15X80s