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will actually be deleted,  but they won't be shown until you turn the
checkbox back on.

   As with many other objects shown in Guide,  you can use "show at"
to tell Guide only to show the images at certain fields of view.  By
default,  images are shown only between zero and 1.6 degree fields of
view.  (They don't tend to look like much of anything above 1.6 degrees,
and there can be so many images at larger fields of view that the program
drags to a stop while drawing them.)

   By default,  Guide will show images in "normal" mode,  with stars
bright and the background dark.  Click on "Invert images",  and they
will be shown in a photographic negative mode,  with the background
bright and the stars dark.

   If you've extracted large numbers of images from CD-ROMs,  you may
want to free up the hard drive space they consume.  Clicking on "Clear
RealSky Images" will do this.  You'll get an "are you sure" message,
and if you confirm,  the images will be deleted.

   To extract RealSky/DSS images from CD-ROM,  you should first center
on the area of interest,  then click on "RealSky/DSS from CD".  You'll
get a dialog box in which you can tell Guide a bit about what size image
you want and whether you want to extract it from DSS or RealSky North or
RealSky South CD-ROMs.  There may be more than one scanned image
covering the region you're interested in;  if so,  you can select the
one you want to use..  (Though in general,  you'll just want to accept
the default image.)  You'll be asked to insert a given CD-ROM, and the
image will be extracted from it.  After this,  you'll be asked to put
the Guide CD back in the drive,  and Guide will draw a chart with your
newly-extracted image shown.

   "Add DSS Image" can be used to import a DSS image you've downloaded
manually from the Internet.  You'll normally want to use the "DSS from
Internet" option,  but there are still some holdouts who prefer to get
DSS images from various servers,  then import them to Guide using this
function.  There are currently at least six Web sites one can visit
and get DSS images from:

http://stdatu.stsci.edu/dss
   (Space Telescope Science Institute)
http://arch-http.hq.eso.org/cgi-bin/dss
   (European Southern Observatory)
http://cadcwww.dao.nrc.ca/dss
   (Canadian Astronomy Data Centre)
http://dss.mtk.nao.ac.jp/
   (National Astronomical Observatory of Japan)
http://terra.bo.cnr.it/skyeye/gb/
   (Instituto di Radioastronomia, Bologna, Italy)
http://ledas-www.star.le.ac.uk/DSSimage/
   (Leicester Database and Archive Service,

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