alias xepr 'perl -p -e "s/\.[\d]+ setgray/0 setgray/"'Then either "source .cshrc" in each of your terminal windows, or log out and log back in. You won't need to worry about this step again.
2. From the View menu, choose Sky View. You can drag the corner of the window to make it bigger, but if you do, hit the "1:1" button at the lower left after resizing, to make the field square.
3. From the Control menu of the Sky View window, choose Filter. From the same menu, choose Options. (Both open windows that you will need.)
4. In the Options window, set Display Mode to RA-Dec, the Grid Control parameters to Grid, Auto, and RA-Dec, and turn off Auto Magnitude and Field Stars (listed under View Options).
5. From the Control menu of the Sky View window, choose Field Stars. In the window that pops up, choose either "Internet to xephemdbd" or "Internet to ESO" to get the HST Guide Star Catalog (GSC).
6. Center your field or target object in the Sky View window, using either the RA and Dec sliders (bottom and right edge of the window) or the Search Memory option under the Objects menu in the XEphem main window. You may need to adjust the Limiting Magnitude sliders in the Filter window to be able to see your targets. Hit the Apply button after moving any of these sliders.
7. Use the field of view slider (left edge of the Sky View window) to zoom in. The field width is shown at the bottom, in degrees:minutes. It is strongly recommended that you use a 1 degree (1:00) field always, unless you have a compelling reason to do otherwise.
8. Go back to the Options window and turn the Field Stars back on.
9. Adjust the plot symbols by changing the Stars Limiting Magnitude in the Filter window. Setting this to the limiting magnitude of the catalog (16 for the GSC) is reasonable. You should now see lots of faint stars in your field.
10. Near the bottom of the Options window, the first line under Labelling says Stars; to the right of this are two buttons marked N and M. Turn the N button off to suppress star names. Turn the right button on to show the magnitudes (decimal points are omitted).
11. To print the map, choose Print from the Control menu of the Sky View window. XEphem has a printing quirk that will produce a difficult-to-read gray map unless you have done the preliminary setup described above and follow this advice: Choose Grayscale and Save to file; the default file name will be "xephem.ps" in your ~/XEphem directory. Hit the OK button. From another Unix prompt, type
xepr < ~/XEphem/xephem.ps | lpr -P[printer]where [printer] is the name of the printer you want to use: pcl (room 255), pcla (room 243), or pclb (room 338). Color charts are not recommended because they are difficult to read at night.
12. Use an appropriately enlarged or reduced copy of the ST-8 focal plane diagram (sec. N of the Observer's Guide) to locate possible guide stars that can be made to fall within the field of the guiding CCD when your target is in the main field. Guide stars brighter than 12th magnitude are highly desirable for the broadband filters; for H&alpha guide stars brighter than 8th magnitude are needed. Trace the main field onto the map so that you will know how to position it to catch the guide star.
Note: XEphem can load only up to a certain number of field stars from the catalogs, so if you have an exceptionally starry field you may get only a fraction of the stars. If you zoom out, you will see that it has loaded the stars only in the vicinity of your field center. Before making a new chart of a new field, turn the field stars off, move to the new field, and turn them back on.