gregbradley
10-09-2010, 02:37 PM
I thought I would post my findings on the relative merits/disadvantages of these 50mm square filters.
I have 50mm sqaure Baader,50mm square Astrodon Gen11, Astronomik (not the latest Gen 11).
With the advent of the 16803 sized chips reflections became a real concern about 2 years ago and there was a lot of discussion on the net about it. So this aspect of the filters is very important.
The Astronomiks are quite good. I got good colour, they didn't cause any troubles and reflections were quite mild. They are thin at 1mm and they need a spacer otherwise they will fall out. Gert now sells the spacers for the 50mm square. He didn't when he first marketed them so they were not useable really then. I'd give them a 7 out of 10. Perhaps colour is a bit weak compared to the other 2 but pleasant. They are also a dye type filter where the glass is transparent with a coloured dye. The other 2 are mirrored reflection type.
The next set I had were the Baader's after reading a lot of posts. These give similar to slightly worse reflections (not bad but could be better). Colour is skewed to the red and red comes out stronger with these filters. They are not 1:1:1 colour combine as the marketing says the are. In fact they are a fair way away from that. What they don't take into account is the different CCD type responses to the various colours. Perhaps they may be 1:1:1 with an 3200ME chip - I don't know. But with 11002 or 16803 chips they are not. I also found them hard to get accurate colour combines perhaps because of this. I had to resort to normalising my RGB masters to get a sensible combine about 2 out of 3 images as otherwise I got silly results. I give them a 4 out of 10 for this otherwise they are good. They seem relatively parfocal - not as parfocal as the Astrodons though. There is a slight difference in focus between the filters so hence another slight weakness with the filters and not matching the marketing claims.
Astrodon Gen 11. These so far are by far the best. They are expensive but worth it. I get virtually no reflections, I get a very pleasing colour combine with no fiddling and a nice balance of colours without being skewed to one colour or another.
I definitely get the best results from these filters and I give them a 9.5 out of 10 with perhaps a mild deduction for being so expensive. But perhaps the rule of "you get what you pay for" applies here. I used to use Astrodon 50mm round filters with my STL11 and I liked those as well.
They did however give some reflections especially the green filter. So I would stick with the Gen 11 even if being used with a smaller chip.
A good choice of filters with these large chip cameras is vital and they are way more sensitive to reflections than the smaller chips. Part of the reason for that is they will always require a flattener in the scope and that these chips are quite a bit more sensitive than the 11002 chipped cameras (66% QE versus 40-50% QE).
I hope this may be of use to someone deciding on which filters to get.
Greg.
I have 50mm sqaure Baader,50mm square Astrodon Gen11, Astronomik (not the latest Gen 11).
With the advent of the 16803 sized chips reflections became a real concern about 2 years ago and there was a lot of discussion on the net about it. So this aspect of the filters is very important.
The Astronomiks are quite good. I got good colour, they didn't cause any troubles and reflections were quite mild. They are thin at 1mm and they need a spacer otherwise they will fall out. Gert now sells the spacers for the 50mm square. He didn't when he first marketed them so they were not useable really then. I'd give them a 7 out of 10. Perhaps colour is a bit weak compared to the other 2 but pleasant. They are also a dye type filter where the glass is transparent with a coloured dye. The other 2 are mirrored reflection type.
The next set I had were the Baader's after reading a lot of posts. These give similar to slightly worse reflections (not bad but could be better). Colour is skewed to the red and red comes out stronger with these filters. They are not 1:1:1 colour combine as the marketing says the are. In fact they are a fair way away from that. What they don't take into account is the different CCD type responses to the various colours. Perhaps they may be 1:1:1 with an 3200ME chip - I don't know. But with 11002 or 16803 chips they are not. I also found them hard to get accurate colour combines perhaps because of this. I had to resort to normalising my RGB masters to get a sensible combine about 2 out of 3 images as otherwise I got silly results. I give them a 4 out of 10 for this otherwise they are good. They seem relatively parfocal - not as parfocal as the Astrodons though. There is a slight difference in focus between the filters so hence another slight weakness with the filters and not matching the marketing claims.
Astrodon Gen 11. These so far are by far the best. They are expensive but worth it. I get virtually no reflections, I get a very pleasing colour combine with no fiddling and a nice balance of colours without being skewed to one colour or another.
I definitely get the best results from these filters and I give them a 9.5 out of 10 with perhaps a mild deduction for being so expensive. But perhaps the rule of "you get what you pay for" applies here. I used to use Astrodon 50mm round filters with my STL11 and I liked those as well.
They did however give some reflections especially the green filter. So I would stick with the Gen 11 even if being used with a smaller chip.
A good choice of filters with these large chip cameras is vital and they are way more sensitive to reflections than the smaller chips. Part of the reason for that is they will always require a flattener in the scope and that these chips are quite a bit more sensitive than the 11002 chipped cameras (66% QE versus 40-50% QE).
I hope this may be of use to someone deciding on which filters to get.
Greg.