Field Of View - Celestron NexStar 90 MAK Instruction Manual

TheSkyX First Light Edition User Guide
compass direction displayed at the bottom of the
screen indicates E, for east. Experiment with the
other compass direction buttons.
In addition to the compass direction buttons, a set of
arrow buttons can be used to shift your viewing
direction incrementally. Click the right arrow
button. Notice how the view shifts slightly to the
left (how far the Sky Chart shifts depends on your
field of view, discussed below), just as if you were
outside, looking at the real sky, and turning your
head to the right. The left, right, up and down
buttons function similarly (if your computer's
monitor is small, or the screen resolution is low, the
entire toolbar may not fit on the screen, so you may
need to click the ">>" symbol to display the up and
down buttons), mimicking the movement of your
head in the indicated directions.
You can also press and hold the key then
CONTROL
drag the mouse to adjust the position of the Sky
Chart.
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Field of View

You probably know that a circle can be divided into
360 degrees. Imagine a pie cut into six equal slices.
The angle between the edges of a given slice is 360
/ 6 = 60 degrees. Astronomers measure angles in
degrees, and fractions of a degree: each degree is
divided into sixty minutes, and each minute is
divided into sixty seconds.
When you look at the sky, you can only see a
portion of it. Imagine for a moment that the sky is
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