Telescope Reviews: Nikon 10X70 IF SP "Astroluxe"

Marco,

I can't and am not saying that the 10x70s are optically superior to the 7x50 Prostars. If anything, I think the Prostars are a little sharper out towards the far edge of the field. Nevertheless, the 10x70 Astroluxes are more than sharp enough so I don't consider that to be much of an issue between them.

For hand-holdable use the 7x50s are better because of their lower power (i.e., easier to hold steadier), smaller size and lighter weight.

Both binoculars perform superbly for terrestrial use (on longer distance targets). The 7x50s have the advantage of a larger true field and the 10x70s the advantage of providing a larger image scale but no drop off in brightness.

For astronomical use I don't use either of those binoculars very much between the months of October and May because the skies where I observe at during those months are not dark enough to enable either of those binoculars to perform well enough that I'm captivated by the views they provide. My 8.5x42 Swaros and 15x60 B/GATs perform much better under "ordinary dark skies" or in suburban settings.

However, under really dark skies at sites far away from any cities or even small towns, then the two Nikons will excel. However, between those two I find the 10x70s to be more useful and consequently I spend a lot more of my observing time with them than I do the 7x50s. Under perfect conditions I will spend maybe 30-45 minutes using the 7x50s to view everything that I think that I can profitably use them on during mid-summer night observing session. However, with the 10x70s I usually spend about 2 hours with them and on the whole come away much more impressed by what I've seen through them. By the way, I could probably spend even more time using them but have to I have to allocate some time to use with my other binoculars and telescope/binoviewer.

Even though both of those binoculars have large 7mm exit pupils, the 10x power of the Astroluxes does seem to darken the sky somewhat and improve the contrast. Also, there is a signifigant difference in image scale between 7x & 10x.
So on the whole more objects look better to me through the 10x70s than they do through the 7x50s.

The 7x50s show the really fainter Milky Way clouds better than the 10x70s do, but the latter show most of the brighter ones much more impressively than the 7x50s do. But the bottom line is that when I'm at really dark sky sites (which I'm usually at for 4 - 8 hour observing sessions on 5 - 10 nights each summer season)I find in practice that I spend at least 3 times as much time observing with the 10x70s than I do with the 7x50s.

So do I think that you should get a pair of the 10x70s? Well, if you can get to some REALLY DARK SKY SITES where the Milky Way is bold and bright to the naked eye, then yes I would recommend getting the 10x70s. However, if you're not able to get to such sites to observe with them at, then I'd recommend that you consider getting a pair of the 15x60 Doctor Optics Nobilems, the 16x70 Fujinons or the 18x70 Nikons instead.

John Finnan