User`s guide

184 Starry Night User’s Guide
How faint can I see?
The stellar limiting magnitude is
approximately 14. Although we have seen
fainter stars — almost 15th magnitude —
we have chosen to be conservative in our
claims. Since Starry Night is comprised of
real images taken under varying
conditions, the actual stellar limiting
magnitude can vary somewhat. However,
in the process of equalizing the imagery
for the mosaic, limiting magnitude
differences have been reduced to less than
those apparent in many published
photographic atlases.
How well do small objects like galaxies
appear inStarry Night?
The native resolution of the original
images is 12 arc seconds per pixel. This
sampling rate allowed us to fit all the sky
image data on one DVD, while still
showing a tremendous amount of detail in
deep sky objects. For example, there is
enough resolution to show structure in the
larger showpiece galaxies. Indeed, the
recorded detail in most "fuzzies" such as
galaxies and nebulae requires 6 to 10-inch
(15 to 25 cm) apertures to see visually.
Starry Night Pro Plus, as it is, is pushing
the limits of modern computer technology
commonly found at home. Had a finer
resolution setting been used, the volume of
data would have ballooned to
unmanageable levels. That would have
made scanning around the sky, currently
so easy with Starry Night, frustratingly
slow.
How far can I zoom in and out?
The widest view possible is 180 degrees,
which is imposed by the projection
currently used. This is equivalent to the
amount of sky visible above an
obstruction-free horizon, or one-half of the
entire celestial sphere. The closest you can
zoom in to is a 0.5 degree high field of
view — at typical monitor screen sizes,
this is equivalent to viewing a globe of the
sky about 240 feet (75 meters) in
diameter!
How well does the imagery show double
stars?
At the imaged resolution of 12 arcseconds
per pixel, two faint stars separated by this
amount would appear as an elongated
blob. In actuality, star images occupy at
least a few square pixels in area, so the
closest resolvable pair would be nearer to
20 arcseconds.
Can I adjust the view in order to
simulate what I might expect to see in
my telescope?
You can adjust the brightness of the
AllSky image to to quite closely mimic a
telescopic view. And when you take Starry
Night Pro Plus outside with your
telescope, switch to night vision (red)
mode to preserve your dark adaption.
Can I capture images of the sky display
for use elsewhere?
You can export areas of interest as an
image by selecting Export as Image from
the File menu..You can save the image in a
number of popular image formats.