Thursday, November 29, 2007

Guiding exercise

Took my TG-SP II out, set it up by the window, put my Borg 45ED II there, insert the 9mm Meade reticle, given the good sky these days, I could easily see three stars in the same field randomly. Balancing the Borg 45ED II requires only the bundled counter weight at nearly the front end, that means if I'm to guide using the Borg with a C mount lens, this counter weight will be enough. Very portable!

I centered the adjustable cross hair of the reticle eyepiece in a star, feels like video game! Then I pressed the red button, i.e. to stop the RA drive, the star drift very nicely. I rotated the eyepiece to align the cross hair with the RA axis. Then I press the blue button to set the RA drive at 2x, soon the star went back to the center. With this simple stop and 2x mechanism, no backlash will be seen, since the drive is always running in a single direction. Simple and elegant.

Then I left the setup for a while, let the star drift.

The mount is not polar aligned basically, I just polar aligned very roughly by pointing it to the magnetic north. :-)

After a few minutes, I finally detect drift. I carefully turn the DEC knob and soon it's back to the place. Turning the knob does not induce much vibration, not really detectable to the view in the eyepiece. A good sign.

Seems like it's a very reasonable setup to do some simple imaging. I always want to do short exposure like within 2-3 minutes with 200mm at most, so I think that's enough.

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