Celestron 91076, Инструкция по эксплуатации

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Specifications
Optical Design
Rowe-Ackermann Schmidt
Aperture
279 mm
Focal Length 620 mm
Focal Ratio 2.22
Central obstruction diameter 114 mm
Optical Coatings StarBright XLT
Optical Window Broadband AR fully-multicoated removable optical window
Focuser Ultra-Stable Focus System
Cooling Fan 12V DC, MagLev, 5.5 mm/2.1 mm tip positive power jack
Optical Tube Dimensions
33 in. long x 13 in. diameter
Total Telescope Kit Weight
35 lb
Backfocus from included camera adapters 55 mm
Total back focus from flat surface above optical window 72.8 mm
Wavelength Range 400-700 nm
On-axis RMS spot size <2.00 µm
RMS spot size 21 mm off-axis <2.25 µm
Relative illumination 21 mm off-axis 78%
Optimized Image Circle Diameter 43.3 mm
Total Usable Field 52 mm
Dew Prevention
The Schmidt corrector is especially susceptible to condensation forming on it because the
glass is directly exposed to the night sky, like the windshield on your car. If the temperature
of the corrector drops below the dew point, dew may form on the corrector within minutes.
The easiest way to help prevent dew is to add an optional dew shield, available from
Celestron, which shrouds the front of the astrograph and reduces radiant cooling of the
corrector. If conditions are more severe, a dew heater, commonly available from other
manufacturers, can be added to apply slight heat to the corrector to keep above the dew
point and dry all night.
If light dew has already formed on the corrector, you can try pointing the astrograph
downward to allow the corrector to warm a bit until it clears. If heavy dew forms, you can
use a hair dryer to heat the corrector and evaporate the moisture until it is clear.
Do not store the astrograph if covered in dew. Allow it to dry first without the dust cover on.
Storing optics when wet can promote mold growth on the optical surfaces.
Cleaning of the Optics
Dust, debris, and fingerprints on the optics will generally have little effect on imaging
with the RASA.
However, if the external surfaces of the Schmidt corrector or the lens group become exces-
sively dirty, they should be cleaned. Dust can be removed with a blower bulb or an optical
cleaning brush. Then, use optical cleaning solution and lens cleaning tissue to remove any
remaining debris or stains. Apply the solution to the tissue and then apply the tissue to the
lens. Use low pressure strokes, do not rub in circles. When cleaning the corrector, strokes
should go from the center to the outer edge. Use a new tissue for each stroke so as not
to spread any oils or debris.
To minimize the need for cleaning, keep the dust cover on the astrograph when it is not
in use.
Cleaning the internal optical surfaces should only be done by the Celestron Repair De-
partment. If your RASA needs internal cleaning, please contact Celestron for a return
authorization number and price quote.
© 2019 Celestron • All rights reserved
celestron.com/pages/technical-support
2835 Columbia Street • Torrance, CA 90503 USA • 10-19
WARRANTY
celestron.com/support/warranties
FCC NOTE: This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential installation. This equipment generates, uses,
and can radiate radio frequency energy and, if not installed and used in accordance with the instructions,
may cause harmful interference to radio communications. However, there is no guarantee that
interference will not occur in a particular ninstallation. If this equipment does cause harmful interference
to radio or television reception, which can be determined by turning the equipment off and on, the
user is encouraged to try to correct the interference by one or more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.
This product is designed and intended for use by those 14 years of age and older.