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Download the raw, full-frame FITS files from
this
folder. Absolutely no processing has been done to
the files. They are the raw, unaltered images. Ask manufacturers
for raw, full-frame files. Otherwise the shape of the stars can
be misleading because they've either cropped in, loosing field
coverage and not showing the actual performance you will obtain,
or they have processed the images (also not showing you the actual
performance). Real-world performance can only be judged from
full-frame raw, unaltered images. |
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The telescope is mounted on an equatorial mount, which is far
more mechanically demanding on the mechanics of the optical system
than an alt/az mounted telescope test. If you plan to mount the
telescope EQ, make sure the sample images you are being shown
were taken on an EQ mount. |
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Focus position was not touched during these tests and on this
design focus is sensitive to +/-8µ from the optimal focus
position. Move outside this 16µ window and off-axis stars
will go comatic. Dream is the industry leader in actual high-stiffness
and high-performance opto-mechanical systems because from day
one Dream has focused on engineered, high-consistency CFSC™ structures that chase stiffness, not
strength. If an optical system requires focus, to compensate
errors that can be seen as the telescope angle changes, it is
a red flag that mechanical bending of the structures is occurring.
Adjusted focus images are not a true indication of total performance.
Ask a manufacturer for raw images where focus and collimation
are not touched at all during testing. |
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Sample images taken 10 minutes after the telescope was slewed
to a new sky position show that Dream has unmatched stiffness;
no focus shift due to sky location (slew to and immediately image)
and no settling affect either. Because of the high stiffness
and athermal nature of Dream's carbon fiber structures and zeroDELTA™ lightweight
mirrors, our opto-mechanical systems are at the cutting edge
of both mechanical and thermal performance. |
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The CCD used is a KAI-11002
chip: 9 microns square, 4008 x 2672 (full-format, 42mm diagonal). |
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Collimation of this and
all of the Dream Astrograph telescopes is achieved by using the
custom tools provided to our customers. They are used during
the day and only once. Collimation was accomplished on the
first day with this telescope, then it was not touched
again (adjusting collimation would change focus). |
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The ambient temperature was -7C (19F, +/-5F)
during these all-sky tests. Dream has tested this telescope design
over as much as a 20°F temperature change and still not detected
degradation of the off-axis quality, all while leaving the focus
position untouched. No other manufacturer is delivering this
level of performance. Dream has been delivering performance since
2003. |
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Use the file number and descriptions below as a quick
reference to know what direction the telescope was pointing for
that given image. |
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2660: Zenith, OTA on east side of mount. |
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2661: North field. |
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2662: same as above but ~10 minutes later. |
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2665: West field. |
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2666: same as above but ~10 minutes
later. |
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2670: South, SW field. |
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2672: same as above but ~10 minutes
later. |
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2673: Zenith but OTA now on west side of
mount. |
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2675: same as above but ~10 minutes later. |
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2677: North field. |
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2678: same as above but ~10 minutes later. |
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2679: East field. |
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2681: same as above but ~10 minutes later. |
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2682: Southern field. |
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2683: same as above but ~10 minutes later. |
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You can look at data from two
additional telescopes on this web site. |
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