Refractor comparisonPosted By Tim Bloser |
Hi,
This is my first post here. A friend and I have just started comparing two refractors: a Televue 85 and a Takahashi Sky 90. We both noticed something interesting I wanted to ask all of you about here.
When we began, the weather wasn't cooperating, so we decided to start with an indoor test. I have seen Al Nagler point his scopes at a dollar bill to show off their optical quality, so we taped a dollar bill to a wall under good lighting about 25ft from the scopes. Using extension tubes, we got both to focus. At 200x, though the views through both looked very sharp and clear, the Televue was a bit sharper, and the difference wasn't too hard to see (we did this using the Tak both with and without its Extender Q).
The next day we took both scopes outside and repeated the dollar bill test. However, this time we set up the scopes about 60-70 yards from the dollar. Naturally we didn't get the same detail on the dollar. But we still noticed that from this distance, the Tak and the Televue were now neck and neck at 200x, and if anything, the Tak seemed to show a clearer view (again both with and without the Extender Q).
This result struck us both as a bit puzzling. Why would the Televue seem noticeably sharper from such close range, and yet not seem sharper (and if anything slightly less sharp) from much longer range? Any thoughts?
(And by the way: the outdoor daytime testing revealed something neither of us expected: even without its Extender Q, the Tak had slightly better color correction than the Televue.)
Sorry if this is a strange question, but we both are curious about these results.
Best,
Tim
This is my first post here. A friend and I have just started comparing two refractors: a Televue 85 and a Takahashi Sky 90. We both noticed something interesting I wanted to ask all of you about here.
When we began, the weather wasn't cooperating, so we decided to start with an indoor test. I have seen Al Nagler point his scopes at a dollar bill to show off their optical quality, so we taped a dollar bill to a wall under good lighting about 25ft from the scopes. Using extension tubes, we got both to focus. At 200x, though the views through both looked very sharp and clear, the Televue was a bit sharper, and the difference wasn't too hard to see (we did this using the Tak both with and without its Extender Q).
The next day we took both scopes outside and repeated the dollar bill test. However, this time we set up the scopes about 60-70 yards from the dollar. Naturally we didn't get the same detail on the dollar. But we still noticed that from this distance, the Tak and the Televue were now neck and neck at 200x, and if anything, the Tak seemed to show a clearer view (again both with and without the Extender Q).
This result struck us both as a bit puzzling. Why would the Televue seem noticeably sharper from such close range, and yet not seem sharper (and if anything slightly less sharp) from much longer range? Any thoughts?
(And by the way: the outdoor daytime testing revealed something neither of us expected: even without its Extender Q, the Tak had slightly better color correction than the Televue.)
Sorry if this is a strange question, but we both are curious about these results.
Best,
Tim
