skymap cursor keys

	c	Replot with celestial coordinates labels
	f	Flip the chart horizontally, reverse X axis
	k	Draw the brightness key, scale, and titles
	l	Label stars with name column
	m	Move coordinate at cursor to plate center
	n	Print table entries for stars near cursor
	p	Zoom out:  replot at twice the scale
	q	Quit
	r	Replot with labels in mm from the center
	s	Replot with labels in "arc from the center
	z	Zoom in:  replot at half the scale
	?	Page this cursor keys help text
	:	Command with arguments (see below)


colon commands;  may be abbreviated to a single letter

	:bright b1 b2	Plot only stars between b1 and b2 mag. 
	:label format	Label stars with name column using format
	:move ra dec	Center at ra in hours, dec in degrees
	:newbox size	Change the search box size to size * default
	:scale s	Replot at scale s in "arc/mm
	:width w	Replot with width w in degrees
	:zoom factor	Magnify (demagnify) by factor