Slew Speeds; Observe The Moon; Astronomical Observing; To Track An Object Automatically - Meade DS-2090 Instruction Manual

Slew Speeds

NOTE:
Do not look through
Autostar has nine slew speeds that are directly proportional to the sidereal rate (this is the
the telescope's eye-
speed at which stars move) and have been calculated to accomplish specific functions.
piece or viewfinder
Pressing the SPEED/? key changes the slew speed, which is then shown for about two
while it is rapidly
seconds on Autostar's display.
moving. Children
The nine available speeds are:
should always have
adult supervision {
while observing.
{
{
{
{
TIP: When a mes-
{
sage is scrolling
across the display,
{
press and hold the
{
Up Arrow key to
{
increase the scrolling
speed or press and
hold the Down Arrow
Speeds 1, 2, or 3: Best used for fine centering of an object in the field of view of a higher power
key to decrease the
eyepiece, such as a 12mm or a 9mm eyepiece.
scrolling speed.
Speeds 4, 5, or 6: Enables centering an object in the field of a low-to-moderate power eye-
piece, such as a standard 25mm eyepiece.
Speeds 7 or 8: Best used for rough centering of an object in the eyepiece.
Speed 9: Moves the telescope quickly from one point in the sky to another.

Observe the Moon

Point your telescope at the Moon (note that the Moon is not visible every night) and practice
using the Arrow keys and the slew speeds to view different features. The Moon contains many
interesting features, including craters, mountain ranges, and fault lines. The best time to view
the Moon is during its crescent or half phase. Sunlight strikes the Moon at an angle during these
periods and adds a depth to the view. No shadows are seen during a full Moon, causing the
overly bright surface to appear flat and rather uninteresting.
Consider the use of a neutral density Moon filter when observing the Moon. Not only does it cut
down the Moon's bright glare, but it also enhances contrast, providing a more dramatic image.

Astronomical Observing

Used as an astronomical instrument, your telescope has many optical and electromechanical
capabilities. It is in astronomical applications where the high level of optical performance is
readily visible.

To Track an Object Automatically

As the Earth rotates beneath the night sky, the stars appear to move from East to West. The
speed at which the stars move is called the sidereal rate. You can setup your telescope to move
at the sidereal rate so that it automatically "tracks" the stars and other objects in the night sky.
In other words, if the telescope is not tracking an astronomical object, the object will drift out of
the eyepiece field of view. The tracking function automatically keeps an object more or less cen-
tered in the telescope's eyepiece.
To track objects, you must first set the telescope in the home position, then initialize Autostar,
and finally select "Targets: Astronomical" from the Autostar Setup menu. You must also learn
how the Autostar keypad operates in order to move through the Autostar menus.
Speed 1 = 2x =
Speed 2 = 8x =
Speed 3 = 16x =
Speed 4 = 32x =
Speed 5 = 64x =
Speed 6 = 0.5° = 120 x sidereal (30 arc-min/sec or 0.5°/sec)
Speed 7 = 1°/s = 240 x sidereal (60 arc-min/sec or 1°/sec)
Speed 8 = 2°/s = 480 x sidereal (120 arc-min/sec or 2°/sec)
Speed 9 = Max = (Maximum speed possible, dependent on battery power)
2 x sidereal (0.5 arc-min/sec or 0.008°/sec)
8 x sidereal (2 arc-min/sec or 0.033°/sec)
16 x sidereal (4 arc-min/sec or 0.067°/sec)
32 x sidereal (8 arc-min/sec or 0.13°/sec)
64 x sidereal (16 arc-min/sec or 0.27°/sec)
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