I just got the Fringe Killer and tried it with my AstroView 90 Refractor. I know there's been a lot of questions about minus-violet filters so here's what I saw.
Seeing was not all that great, maybe 4/10. Because of this I held the power down. Saturn was 70 degrees high. There were occasional moments of steadiness.
At 100X without the filter I focused on Saturn and of course, it looked good, but with the trademark violet fringe. Not bad but it was there. I put the Fringe Killer in and yes, it did reduce the violet but not by as much as I would have liked, about half. The main benefit seems to be in sharpness, which is what Baader claims. Again, not a humungous difference but enough to make it worth it.
I had previously tried the Orion V-Block and it didn't do much. The Fringe Killer works better.
After a while I thought, since I had used a #12 yellow filter with minor success, probably mostly due to narrowing the spectral passband, I'd try stacking. That's when it got interesting. The violet dropped some more and the sharpness went up considerably. There was what I'd call a humungous difference. Contrast was excellent, the sky was quite dark, but from 15 miles from center city Philadelphia, you don't get black. But this was far better than I'm used to.
I don't know what Apo views look like, but I've owned a lot of scopes including several small refractors, and this is the best resolution and contrast I've ever had. Due to the seeing, my 8 in SCT could not keep up with the AstroView on this particular night. The colors were quite natural, I guess the violet cast and the yellowish tints came pretty close to correcting each other. Or maybe my eyes adjusted. But it looked great.
The rings showed nice detail - contrast was pronounced between the various sections of ring, with a thread-like quality toward the outside. Banding on the globe was more contrasty than even the SCT on a good night.
I'm a pretty happy camper.
Bob
Seeing was not all that great, maybe 4/10. Because of this I held the power down. Saturn was 70 degrees high. There were occasional moments of steadiness.
At 100X without the filter I focused on Saturn and of course, it looked good, but with the trademark violet fringe. Not bad but it was there. I put the Fringe Killer in and yes, it did reduce the violet but not by as much as I would have liked, about half. The main benefit seems to be in sharpness, which is what Baader claims. Again, not a humungous difference but enough to make it worth it.
I had previously tried the Orion V-Block and it didn't do much. The Fringe Killer works better.
After a while I thought, since I had used a #12 yellow filter with minor success, probably mostly due to narrowing the spectral passband, I'd try stacking. That's when it got interesting. The violet dropped some more and the sharpness went up considerably. There was what I'd call a humungous difference. Contrast was excellent, the sky was quite dark, but from 15 miles from center city Philadelphia, you don't get black. But this was far better than I'm used to.
I don't know what Apo views look like, but I've owned a lot of scopes including several small refractors, and this is the best resolution and contrast I've ever had. Due to the seeing, my 8 in SCT could not keep up with the AstroView on this particular night. The colors were quite natural, I guess the violet cast and the yellowish tints came pretty close to correcting each other. Or maybe my eyes adjusted. But it looked great.
The rings showed nice detail - contrast was pronounced between the various sections of ring, with a thread-like quality toward the outside. Banding on the globe was more contrasty than even the SCT on a good night.
I'm a pretty happy camper.
Bob
