Starry Night FAQ
Frequently Asked Questions For Starry Night
Starry Night Pro 4.x FAQ
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Open the Find pane and double-click on the Moon’s name. If you get a message saying that the moon is beneath the horizon, click the Reset Time button. Zoom in on the Moon if you want a closer look. Now change the time step in the Control Panel to a discreet value of 1 day. Use the Single Step Forward button in the time mode controls to watch the Moon's phase change day-by-day. You may have to hide the horizon by choosing View->Horizon to keep the Moon in view.
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The position of the eight major planets should be accurate to within 5 arcseconds
for times within 3000 years of the present. The theory used to predict Pluto’s
position is less accurate: between the years 1885 and 2099, its position is
accurate to within 1 arcsecond, but the accuracy will decline significantly
outside these dates. The position of our moon should be accurate to within 10
arcseconds for several thousand years in either direction. The theories used
to predict the positions of other moons are simpler and therefore potentially
less accurate.
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Starry Night Pro uses a file called "JupiterGRS.txt" located in the Sky Data folder to determine the mean longitude of the GRS. To change the GRS's position you can open this file and enter a new mean longitude. The GRS drifts non-algorithmically so the GRS mean longitude will need to be updated from time to time. The latest mean longitude is available from Sky & Telescope's excellent Great Red Spot web page.
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The orbits of Pluto and Neptune do overlap. However, because the orbit of Pluto
is tilted at an angle to that of Neptune, it can appear from your perspective
that Pluto is always outside Neptune. A neat way to see this is as follows:
Choose "Go | Solar System" and rotate your view so that you are directly over
the north pole of the sun looking back down on the solar system. The orbit of
Pluto will appear to be completely outside the orbit of Neptune. Now blast off
using the elevation button until you are about 3000 AU above the sun. Use the
zoom button to enlarge your view so you can clearly see the two orbits. Now
you can see that Pluto's orbit does come within that of Neptune. The "correct"
view of the orbits can only be seen when you are very far away, and the effect
of Pluto's tilt is small compared to this distance.
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Unfortunately, predicting comet positions on past trips around the sun is one
area of astronomy where simulation programs like Starry Night are not very effective.
As a comet goes around sun, its orbit is altered by the gravitational
influence of the sun and planets in ways that can't be predicted by Starry
Night. The gas and dust released by the comet as it gets closer to the Sun also causes the orbit of the comet you are interested in to change. For example, the orbital period of Halley's
comet has varied from 76 years to 79 years over the last thousand years. The
bottom line is that the orbital elements for a comet in Starry Night are valid
only for its most recent trip around the sun and can't be used to predict its
appearance in the more distant past.
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With Starry Night, you can add Solar System objects such as asteroids, satellites
and newly discovered comets using the Orbit Editor. For more information, refer
to the Starry Night Pro User's Guide. You can also download the latest comet,
satellite
and asteroid
files which have updated orbital elements for the 100 or so most prominent of
each of these objects.
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See our Orbital Elements Page for this information.
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The orbital elements of artificial satellites (including the ISS) are constantly being adjusted slightly. You need to update satellite elements on a regular basis to keep the satellites in their proper position. You do this by choosing "Livesky->Update Comets/Asteroids/Satellites", which will download new elements from our website. You need to close and reopen Starry Night before it will use the new elements.
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The file "Prefs.txt" in the "Starry Night Pro 4\Sky Data\Prefs\" folder has fields named "MaxNumOfAsteroids", "MaxNumOfComets", "MaxNumOfSatellites" and Starry Night will only read in a number of objects equal to the values in these fields. You can change the values of these fields to read in more objects (this may slow the program down if you read in too many objects).
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This feature will not work properly under certain conditions. If you are
connected to the Internet via a proxy server, you will be unable to use this
feature. We plan to add proxy support for a future version of Starry Night.
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