The OAG uses a small prism to
direct light into the Lodestar camera. Pulseguide commands are sent to the
mount to ensure that the selected guide star does not deviate from its original
position.
Because
the Lodestar is rigidly connected to the main imaging camera, flexure is
totally removed. |
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This shows the prism and the
main camera CCD.
The
thumbscrew allows the prism position to be adjusted. If it is too close to the
main CCD it will obstruct the light forming the image - if too far away not
enough light will enter the guide camera to form a useable
image.
I suspect
trial and error will determine the optimum position.
The main camera is focused on the
star field and then two small grub screws allow the guide camera to be adjusted
to achieve focus also. Once this position is found it should not need to be
altered.
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This is a stack of 6x 6minute
exposures of part of the Dumbbell Nebula. Stars are nice and round showing that
the guiding is working
well.
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Full size
image
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