Hi Lawrence,

Short answer: go to the Inversion dialog, and select "Zenith Up". Keep the
simple cylindrical projection (or at least some sort of cylindrical projection).

Longer answer, explaining why the above works:

As you found, just selecting a simple cylindrical grid (or any other cylindrical
projection), and doing nothing else, gets you a projection in which following a
vertical grid line shows changing azimuth, but constant right ascension. Following
a horizontal one gets you a constant declination. This is similar to, say, a
Mercator projection of the earth, where meridians of longitude are vertical lines
on the map and parallels of latitude run horizontally. The North and South poles
become lines at the top of the map... which, for star charts, means the areas
around Polaris and Octans. (Which is why you don't _usually_ use a cylindrical
projection for star charts.)

Switch to "Zenith Up", and Guide stops projecting RA/decs and starts projecting
alt/azimuths. Suddenly, it's the lines of constant azimuth that project as vertical
lines and the lines of constant altitude that become horizontal lines on the chart.
And instead of the north and south celestial poles getting horribly distorted, it's
the areas around the zenith and nadir that look ugly.

Actually, as Konstantin suggests, you could make a user-defined "horizon" that
shows what you're looking for. As you may have seen, you can go into Display...
Backgrounds, turn on "Horizon Objects", and get a slew of objects (trees,
mountains, houses, cars, streetlights, etc.) shown around your horizon.
If you edit the files 'horizon.dat' and 'objects.dat' in your Guide folder,
you'll see that you can modify these. Most people do so just to alter the
horizon to show what's blocked at their site. A few people have added circles
above a particular declination or altitude, to show the area they can't image
because of their equatorial mount or "Dobson Hole" situation. But you could,
in theory at least, make a box that shows your observatory shutter.

Dunno if I'd recommend this, though, because (unlike the objects around
your horizon) your shutter moves from time to time. I didn't really have that
in mind when I put the horizon system together!

-- Bill