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40"
Dream Telescope & Facility |
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Because of the huge CCD chip and fast (f2.4) focal
ratio, a large (10") prime focus corrector is required.
There will be no greater than 8-9% light loss in the extreme
corners of the 111.7Mp CCD camera. |
The Prime Focus Assembly (PFA) is held by a PI
hexapod. The back of the hexapod
is affixed to the spider cage, which in turn is tensioned to
the upper ring of the telescope structure through the spider
vanes. |
The hexapod gives the telescope
an active prime focus assembly, due to its six Degrees Of Freedom
(DOF). |
The hexapod can move +/-2" X, Y and +/-1"
Z. All while having the ability to obtain a given actual position
within +/-1 micron over the entire range. This allows the use
of a "fixed" primary mirror, since the hexapod can
move laterally, then adjust tip/tilt and finally come to focus.
The system can therefore be perfectly collimated and focused
across the entire sky. |
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The telescope structure's declination attachment point
is facing down, near the lower/mid center of the structure. |
The primary mirror covers (carbon fiber) are also
shown in the rendering to the left, in the open position. The
prime focus corrector resides inside a baffle. The telscope will
be parked at a zero zenith angle, thus reducing dust
buildup on the prime focus corrector. |
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The carbon
fiber telescope, with all components shown to the right,
will weigh less than 500 lbs. This is less than 1/4 a conventional
telescope. |
A conventional 1m/40" telescope's primary mirror
alone can weigh 500-600 lbs. |
The use of a cellular
primary mirror and carbon fiber skinned sandwich
core structure and sub components allow this telescope to be
lighter, stiffer and track
ambient temperatures far better than other telescopes. The dome's
design was also based around sound thermal features that help
to produce the highest Delivered Image Quality (DIQ). |
If the DIQ can be reduced from a FWHM of 1.25 to 0.85
arc seconds, exposure times can be cut in half to reach the same
magnitude: 28 versus 14 minutes to reach mag 25 with a s/n=3
in r'. |
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The comparison to the left shows the 40" Dream
above the 0.4m (16") Dream
Astrograph for scale. |
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To learn more about
The Madawaska Highlands Observatory, please visit their web
site. |
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