Re: Drives for CCD photography

Hi Jim:

Insufficient? Maybe, maybe not. Chances are your mount, if well aligned
and balanced, will be just as good for CCDing as it was for film. That
said, if you're using a fairly small chip and fairly long focal
lengths, those guiding errors do tend to be pretty derned annoying.

There are ways around that, however. Many folks use short exposures, in
the 30 second range, and stack multiple images to create a final image.
If you can guide your scope, either manually or with an autoguider,
that's another out. Best advice? Try your mount before you throw it on
the scrap heap. If you are going to buy a new mount, what should you
look for?

Sturdiness.
PEC (it can help a lot).
An ST-4/SBIG compatible autoguiding port.


Jim Klein wrote:
Hi,

In visual and film photography through telescopes on equatorial
drives, the old RA drive system might use commercial gears (Boston
probably) and a synchronous drive motor like a BODINE or a HURST. This
would be controlled using a variable frequency controller.

This was used in conjunction with a DEC drive with another synchronous
motor and gears.

A contol box, held in the hand with 4 buttons and a reostate type
device for setting the system to a siderial rate would be used.

The user kept the target or a near by star in the cross hairs of a
guide scope or off-axis guiding device.

I have been told that this configuration is insufficiently accurate
for CCD photography

.