Posted By Ed Zarenski
Resolution notes: For wide, open clusters, I carefully pick outline boundaries and count stars within to see how deep binocs can see. On the Christmas Tree cluster, NGC 2264, both the Oberwerks see 17*, the Fujinon see 19*. On M44, 15x70s see 71*, 20x80s see 73*, the Fujinon 16x70s see 80*. Several other clusters produced similar results.
On small dense clusters that often just look like a glow in binoculars, I saw a real difference. The Fujinons contrast and resolution made it easier to discern stars within the glow of tight clusters. On M36, Ob15x70 saw 4*, Ob20x80 saw 4*, Fuji16x70 saw 8*. On M37, the 15x70s saw 3* while the Fujinon 16x70s saw 8*.
The Fujinon can be focused to a finer point of light than either of the Oberwerks. The Fujinon contrast and resolution makes it easier to pick out the fainter stars and pick out the stars embedded in the glow of many in the small tight clusters.
Although all the binocs could see the Pinwheel, the contrast in the Fujinons made it much easier to see the faint diffuse light of M33. Last week, using the Fujinons, I found M31 in daylight about 30min before darkness. Saturn’s rings are separated from the disk in all three binocs. The Trapezium is resolved to 3 stars in all three binocs. A-B at 8.7” is not resolved, but several times did appear elongated in the Ob20x80 and the Fuj16x70.
Cold weather notes:
I viewed for about an hour or two on Saturday night. I left the binocs out over-night so the equipment would be set up for a 5AM session. Temperature in the evening was in low/mid 20s, by morning temp was 18°.
The Fujinons were exactly as I left them, focused and ready to go. Both the Oberwerks changed focus, had to be refocused. I did gain additional diopter range on the 80's, which I usually have at the max minus even with my glasses on. Didn't need them at max minus in the morning.
The Oberwerk 20x80 became nearly impossible to move the focus dial.
The Oberwerk 20x80s changed collimation. They were out by morning.
Could it be the mass and length of the steel barrles has such a coefficient of expansion that the 20x80s literally changed shape overnight?