Telescope Reviews: Fuji 25x150 Observing Report

I just got back from 4 days at the Rocky Mountain Star Stare with the new (to me) Fuji 25x150s. I have a few comments about them, but the upshot is that I'm very pleased with their performance. Limiting magnitude there was about 6.5 so it was reasonably dark.

Observing:

I got to spend quite a bit of time scanning the summer Milky Way. By far the most impressive object was the the Lagoon Nebula (M8). The amount of nebulosity surrounding the cluster was jut amazing. Certainly more than I've seen in any other instruments I've owned.

Some objects were so bright they seemed "over exposed". This was true of the Swan Nebula (M17) and the the Wild Duck cluster (M11). At 25x they were smaller than I'm used to in a scope, but they were so bright that they didn't have the translucent look you get in scopes. They were almost solid white patches.

The Small Sagittarius Star Cloud (M24) was a huge swarm of pinpoints of light, backed by the unresolved glow from a multitude of fainter stars. The two dark nebulae B92 and B93 on the NW edge of the star cloud stood out with their inky blackness.

Another highlight was the Andromeda Galaxy (M31) and its companions. It was only about 25º up when I observed it but M31 filled the 2.7º FOV with a distinct dusk lane on its north west side. The companions stood out well and were obvious. This fine view was very memorable.

The Double Cluster was also a treat. This has always been one of my favorite objects with my TEC 180 refractor and a 35mm Panoptic eyepiece. The view in the Fuji's rivaled the TEC's view. The stars are a bit sharper in the TEC, but that is a very expensive APO. The binocular view made up for any small difference in sharpness.

While near the Double Cluster, I swung over to Stock 2, a large (~ 1º) open cluster to the north. The FOV in the Fuji's really framed this object well and the twin 6 inch objectives pulled in the faint stars for a memorable view. One other experienced observer with me said it was the best view of Stock 2 he'd ever seen.

Mechanics:

One concern I had was the stated minimum IPD of 60mm for the binocs. The minimum actually measures more like 58mm which is very close to my eye separation. As it turns out, the eyepieces close down just right for me. My preferred setting was actually about 1 mm larger than the minimum. The large eye lenses and the large exit pupil made eye placement fairly forgiving.

As I mentioned in an earlier post, the eye relief was adequate for observing with glasses. I could see about 2.5 of the 2.7 FOV and that was just fine. My facial structure was also such that I had no problem with "nose relief" which I understand is a problem for some (similar to the Fuji 16x70s).

Another concern was whether this instrument would be good for public outreach, which I do a lot of. Although this star party was not a public event, there were quite a few people there that had obviously never look through a scope much. I got many comments from folks on how they much preferred the view through my binoculars. They said it was much easier to look with two eyes. In most cases I never changed the focus or IPD from around 60mm and the majority were able to enjoy the view just fine. Excellent!

The UA Sirius Mount worked very well. Even observing near zenith was fine for quick looks. On the Meade Giant Field Tripod, I was able to stand fully erect underneath the eyepieces when observing straight up. Motions were smooth and predictable.

The one problem was that the vertical "center of gravity" adjustment on the right angle bracket would slip a bit. If I tightened it enough to prevent slippage, then the altitude motion was too stiff. I contacted Larry at UA about it and it turns out Im missing a spring washer that goes under the tightening nut. He said it is not something I'll find locally so he is sending one out to me. Larry's support has been great during this project. He also had to make a new mounting post for me with the correct holes for the Meade GFT I have.

Cons:
I'm quite happy with the setup. The only thing I'll sort of miss is changing magnifications. 25X is a great overall compromise, but I occasionally wished for something to bump it up to 40x or so. It wouldn't surprise me if it were possible to manufacture an optical train to attach to the eyepieces that would double the power. Something to explore.

Bill