Vixen Sphinx SXP - Manual (Page 58)

East
West
North
South
★
・
・
・
・
・
West
East
North
South
★
・
・
・
・
・
East
West
South
North
★
・
・
・
・
・
(Inverted View) (Erect View) (Mirror-Reverse View)
Look for east
in the sky
Chapter 5 APPLICATION
Drift Alignment in the Northern Hemisphere
East West
North
South
★ ・ ・ ・ ・ ・
West East
North
South
★ ・ ・ ・ ・ ・ East West
South
North
★ ・ ・ ・ ・ ・
(Inverted View) (Erect View) (Mirror-Reverse View)
Precise Polar Alignment (Drift Alignment)
Look for south
in the sky
1
2
If you align the mount with the provided polar axis scope correctly, the mount will be able maintain tracking celestial objects within the field
of view of your telescope's eyepiece. For astrophotography, it enables you to take exposures of 5 to 10 minutes with a telephoto lens of
200mm focal length or less.
However, if you want to take longer exposures than 10 minutes or use a telephoto lens of longer focal length than 200mm, more precise
polar alignment is required. The following method of polar adjustment will be done by watching the movement of a bright star in the
eyepiece and it is called drift alignment.
Align the mount to the north celestial pole by using the polar axis scope. This will save time during the process of drift alignment.
Align the Mount in Azimuth
Prepare an eyepiece with illuminated reticle (cross hairs) or you use a Vixen OR12.5mm with illuminated reticle. Choose a bright star
near the celestial equator and near the meridian, and put it in the filed of view of the eyepiece. Turn off the power switch of the mount
momentarily while looking into the eyepiece to see which direction the star moves. Confirm the west and rotate the eyepiece so that one
of the cross hairs is parallel to the east-west direction in the field of view. The figure on the right shows the directions of north, south,
east and west in the eyepiece according to a type of your telescope with or without a star diagonal.
3 Align the Mount in Altitude
Choose a bright star near celestial equator in east but not too low, and put it in the filed of view of the eyepiece. Turn off the power
switch of the mount momentarily while looking into the eyepiece to see in which direction the star moves. Confirm the west and rotate
the eyepiece so that one of the cross hairs is parallel to the east-west direction in the field of view. The figure on the right shows the
directions of north, south, east and west in the eyepiece according to a type of your telescope with or without a star diagonal.
The following descriptions are based on a telescope without a star diagonal.
Drive the mount at sidereal rate and look into the eyepiece to monitor the drift motion of the star in the north-south direction.
If the star drifts north (i.e. moves down due to inverted view), move the mount to east in azimuth.
If the star drifts south (i.e. moves up due to inverted view), move the mount to west in azimuth.
Adjust the mount with the azimuth adjustment screws. Make appropriate adjustments to the polar axis to eliminate the drift.
The following descriptions are based on a telescope without a star diagonal.
Drive the mount at sidereal rate and look into the eyepiece to monitor a drift motion of the star in the north-south direction.
If the star drifts south (i.e. moves toward the lower left due to inverted view), move the mount to low in altitude.
If the star drifts north (i.e. moves toward the upper right to inverted view), move the mount to high in altitude.
Adjust the mount with the altitude adjustment screwｓ. Make appropriate adjustments to the polar axis to eliminate the drift.
Refrain from doing the star alignment with the STAR BOOK TEN if you need to perform the drift alignment. If the mount type is chosen
as "Equatorial mount without polar setting", the position information collected by the star alignment will be applied for the polar
alignment. This will spoil the drift alignment as any drifts from the celestial pole are detected and corrected automatically. Choose
"Equatorial mount with polar setting" to avoid these corrections. Also turn off the function of depressing atmospheric refractions.
CAUTION
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