My first impressions after unwrapping, were the robust
looking nature of the telescope, attention to detail throughout and very
professionally made. I opted for an AstroPhysics rear thread so that I could
use my AP accessories. The micrometer focuser is a joy to use, perhaps not
as smooth as a feather touch but very accurate and there was no discernable
focus shift when focusing with a CCD camera, a must! The tube rings are
solid and open via a quick release clamp. I like the quality of the dew
shield which snugs firmly onto the OTA. There is also a "wheel" on the rear
of the OTA allowing one to rotate the tube when required.
The day the TEC MCT arrived, the forecast was poor for that
evening, indeed a cold front quickly passed though with a little rain and
amazingly left a clear spell for 2 hours. I firstly star tested the scope
confirming that collimation was dead on and there was one residual heat
plume, but thin and I doubt had much effect on the in focus star pattern.
One concern with these larger MCT's is cool down time and TEC offer a
cooling system utilising a peltier device. My first experience was that I
might get away without it, although the larger swings of summer temperature
would be more of a test.
Star test - The seeing wasn't great after the cold front,
but in and out of focus images were very similar, just a trace of spherical
aberration visible. In focus, at times I could just see parts of the first
diffraction ring, but the star was boiling quite a lot. I hope to repeat
this with better seeing. I turned the scope to Saturn which was over my
neighbours house, but it gave a surprisingly crisp and steady image. Several
belts with subtle colour could be seen, Cassini's division was obvious all
the way round with the top of the globe now visible. The Enke minima was
clear and colour of the rings quite striking. Lastly a quick look at the
moon where Plato was well illuminated, I could see 2 cratelets which was not
anticipated in this seeing.
Next onto a CCD camera. I cobbled my ST10 onto the back of
the OTA, went through the usual routine of focusing, calibrating and tried
short exposures of the Eskimo nebula. I tried this because it is bright and
the gibbous moon was in the west. I measured the FWHM at 2.2 arc secs which
is excellent from my site and given the atmospheric conditions. I am
therefore optimistic that future images will have better resolution.
Below is the Eskimo image - 5x6 minute exposures
Are there any negatives of the TEC MCT? The rear opening of
the back plate is small so vignetting might occur with large format CCD
camera's, but i suspect this is part of the design. The OTA is made of
aluminium so focus may change with dropping temperatures. There is less back
focus than for SCT's, but initial use of binoviewers and CCD equipment
suggests this will not be an issue. Lastly, I thought I was buying a 10 inch
scope, but in fact the mirror is 250mm in diameter which is 9.85 inches, so
I will ask Yuri for a refund!
Finally, I purchased the Scopeguard case that is of real
quality and essential if transporting a quality scope around.
