Before using the scope photographically,
I replace the visual focuser
(an old Sky Micro Giant)...
... with a low-profile, helical, photographic focuser (from Novak).
In the field, I set up the scope & mount, and spend some time polar aligning. I use the "drift method" of alignment. This requires finding a star near the zenith, centering it in (preferably) a reticle eyepiece, and (with the drive running) watching whether it drifts north or south. This determines whether the polar axis is pointed east or west of the pole. I repeatedly adjust the azimuth until there is no further north-south drift over some long period of time (say, 10 minutes).
Then, using a star in the eastern (or western) sky at about the altitude of the pole, the same kind of measurement determines whether the polar axis is pointed too high or too low. Again, repeated adjustments are made until the drift is eliminated.
This process can be repeated, (the more iterations the more accurately aligned the scope will be), but I've found it not really necessary to do that for less than 1-hour exposures, especially if I use the same observing site each time and leave the altitude set the same. However, that requires the mount to be carefully leveled first!
The whole process usually takes me about 45 minutes.
Now, adding a Lumicon Newtonian Easy-Guider (from Lumicon, of course),
a Duo-View adapter from Spectra Astro Systems,
a Celestron 40mm Plossl (viewing port),
and an eyepiece for the guide port,
I'm ready to find and center my target and my guide star.
The 40mm Plossl gives a field of view that approximates the
field of a 35mm film frame,
and thus allows accurate placement of the object for photographing.
The eyepiece shown in the guide port is a 9mm Meade Plossl
with an illuminated reticle,
which is useful for accurate centering of the guide star
in a field of view appropriate for the SBIG ST-4 autoguider.
However, for locating and initially centering the guide star,
I use a Celestron 25mm RKE in that guide port.
That eyepiece happens to be pretty much parfocal with the ST-4,
and provides a wide enough view that
I can easily get the guide star in the field.
More astrophoto equipment can be seen at Page 2.
