Meade Instruments LX200 - Manual (Page 39)

Meade Instruments Corporation - Meade LX200 Instruction Manuals
stars that are not too close together–try to use stars that are at least 90° apart. Do not use Polaris as one
of the stars because RA changes very fast at the Pole and minor centering errors can translate to large RA
pointing errors. Also, avoid stars near the zenith (straight up) since azimuth changes very fast in this area.
Generally speaking, choosing two stars as far apart as possible will yield very accurate pointing.
[ toc ] c. Unknown SITE
To use the LX200 telescope at an unknown location, use the following procedure:
(1) Select site #5 (UNKNOWN) from the SITE menu. (Note: This site cannot be edited like site numbers 1-4
as described on steps 4-10.)
(2) Follow the Keypad display prompts to select and center the two alignment stars.
As described above, the LX200 will check the accuracy of the two stars and give the "Align Mismatch -
Check Stars" message if it detects an error.
[ toc ] d. Which Alignment Method To Use?
Each of the three methods described above have advantages and disadvantages. The following table
summarizes these properties.
Pointing Accuracy
Determined By:
Atmospheric
Refracting
Correction*
Atmospheric
Refraction
Correction
Determined By:
When Best Used
1-Star Known
SITE Level of
Telescope
Yes Level of Telescope
Best used when the
telescope is
permanently
mounted and
accurately leveled.
2-Star: Known
SITE
2-Star Alignment Yes Level of Telescope
Best used on a
transportable
telescope with the
SITE information
available.
2-Star:
Unknown
SITE
2-Star Alignment No N/A
Best used when the
SITE information is
not available.
*Atmospheric Refraction Correction: Light from a astronomical object is "bent", or refracted, as it
passes through the atmosphere. This bending is more pronounced near the horizon because there is
more atmosphere for the light to pass through, and it shifts the apparent position of the star. The
LX200 calculates this bending and compensates for it when slewing to objects near the horizon.
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