Takahashi video about CCA-250
Posted 13 November 2012 - 11:59 PM
The video is of quite poor quality but might be still interesting since it shows a quick view into the production:
Posted 14 November 2012 - 07:58 AM
So this is their corrected cassegrain astrograph that replaces the BRC-250, (corrected-RC). It is another example of a flat field design that relies on a spherical secondary and corrective lenses toward the image plane. So - it is similar to cdk but faster at f/5 and with wider field, but much larger central obstruction at 58%, and uses 3 instead of two lenses. Also - it focuses with the secondary, and has two other f/ratio options with added lenses, at f/3.6 and f/7.5.
It has a very wide field out to 80mm diameter - but I'm not sure what detector you would use with that.
Posted 14 November 2012 - 12:10 PM
Inconsistently misshapen stars at the edges of our U16 field caused us to send it back. Tak had it for 6 months trying to figure out what was wrong with it. Finally decided that the optics were mis-figured and sent and entirely new one.
Focuser didn't work out of the box on the new one. Motors didn't turn, didn't even make a sound when trying to focus. Back it went again where they replaced the motor and controller. Got it back two weeks ago and again, out of the box the focuser still didn't work. Motor turned, but the secondary didn't move. It's gone back for the last time. Almost 18 months of screwing around and nothing to show for it. Good riddance.
Posted 14 November 2012 - 01:47 PM
Posted 14 November 2012 - 07:59 PM
Well that is bad news... maybe the system is just too complex.
They have on in the showroom of Starbase here in Tokyo, looks impressive but the price is incredible and it is a pure photographic system.
Hopefully they can fix the problem this time around, so as I understand you were never able to use it?
Posted 15 November 2012 - 05:43 AM
Posted 16 November 2012 - 10:33 AM
However, it's been 13 months now since original purchase, two of which the scope was in our actual possession, and the optics in the current one that has been shipped back and forth 4 times are still a question mark as the focuser has never worked on the replacement.
I'm still skeptical.
Posted 16 November 2012 - 07:22 PM
I would love to hear how the optics perform.
I fully agree, that a problem can happen once, but not three times.
It leaves some questions regarding the stability of their design...