Meade LX200 Instruction Manual page 22

d. PARAMETERS: Press ENTER at the PARAMETERS menu
to find options that let you set such parameter limitations on
the objects that you wish to locate as the following:
Type
Visual object quality range
Horizon
Zenith
Size
Brightness
Field of view
You can scroll through the PARAMETERS menu using the
PREV or NEXT key. To edit, move the arrow to the desired
option, and press and hold ENTER until you hear a double
beep and see a blinking cursor (except in the BETTER
option). Where numerical values are to be input, type them
in from the keypad. If you make a mistake, you can move
the cursor backward using the W key, and re-enter the data.
To exit to the Main option menu, press the ENTER key once
again.
1. The TYPE GPDCO option lets you select the type of
CNGC objects that you wish to locate. Initially, the
blinking cursor appears over the G symbol, for Galaxies.
If you do not want to look for galaxies, press NEXT; the
symbol changes from an upper case G to a lower case
g. If you wish to keep GALAXIES selected, move the
blinking cursor over to one of the other category symbols
by pressing the W or E key on the keypad. You can then
deselect the undesired categories.
Parameter categories are abbreviated as follows:
OBJECT SYMBOL LEGEND
SYMBOL
G
P PLANETARY NEBULAE
D
C GLOBULAR STAR CLUSTERS
O OPEN STAR CLUSTERS
If you wish to recall a category symbol, move the blinking
cursor over the symbol and press the PREV key. After
your selections are made, press ENTER.
2. BETTER: The BETTER option lets you define the visual
object quality range. At power-up, the range is set at the
bottom of the scale, on VP for VERY POOR. The START
FIND option will select all objects that are very poor
through super or what could be considered an ALL
OBJECT-QUALITY SYMBOL LEGEND
SYMBOL
SU
EX
VG
G
FR
PR
VP
setting. The object-quality symbols are as follows:
If you wish to define the object quality range to Very
Good and better, press the ENTER key until the symbol
VG is displayed. From the VP setting to VG requires
three ENTER key presses. The LX200 now selects
DESCRIPTION
GALAXIES
DIFFUSE NEBULAE
DESCRIPTION
SUPER
EXCELLENT
VERY GOOD
GOOD
FAIR
POOR
VERY POOR
objects that look Very Good through Super.
3. HIGHER: The Higher option sets the horizon setting for
the telescope. At power-up, the setting is 00°, which
assumes that you have an unobstructed line of sight to
the horizon in every direction. If, however, there are
obstructions to viewing a level horizon or if the sky
quality is poor due to haze or light pollution, you can set
an artificial horizon level. Your LX200 will not try to find
objects below your setting.
Enter the number of degrees above the horizon that will
clear the obstructions in the sky. To estimate how many
degrees the obstruction is taking up of the sky, hold your
fist at arms length. Each fist diameter is approximately
5°. So, if a tree is three fists high, you would set 15° in
the HIGHER option. Once the setting is finalized, press
ENTER.
4. LOWER: The LOWER menu file option sets the zenith
limit setting for the telescope. At power-up, the setting is
90°, which assumes that you point the telescope straight
up. If, however, you have instruments on the telescope
which will not clear the fork arms, or if you want to avoid
the 10° field de-rotator limit, this setting can be used.
Enter the number of degrees from the zenith that you
want to limit. Once the setting is finalized, press ENTER.
5. LARGER: The LARGER menu file option allows settings
of the lower apparent size limit of the objects you wish to
see. At power-up it is set to 000' (arc minutes). In order
to make a decision as to the size limits that you may
impose, it helps to have a clear understanding of exactly
what an arc minute of sky is. A good example is the
apparent size of the Moon, which could be expressed as
1/2 of a degree, 30 arc minutes, or 1800 arc-seconds.
Each arc minute is 60 arc-seconds, and there are 60 arc
minutes for each degree of sky.
Some beginning observers have a tough time discerning
objects less than about 1 arc minute in size unless it is a
double star or a planet. Astrophotographers and those
involved with CCD imaging may want to set a higher
value based on the desired image scale coverage that
would be most impressive with different types of films or
CCD cameras. Enter the new value in arc minutes, then
press ENTER to exit to the option file.
6. SMALLER: This menu option is the upper size object
limit. At power-up the setting is for 200 arc minutes or
3.33°. This setting is high enough to cover the largest
objects in the OBJECT LIBRARY.You may want to lower
the value because of true field-of-view limitations of a
particular eyepiece (see the RADIUS parameter option
for calculating true field).
Other reasons for limiting the value in SMALLER is for
astrophotographic or CCD imaging requirements where
we don't want the object to exceed the imaging area of
the film or the CCD chip.
7. BRIGHTER: The lower brightness limits based on stellar
magnitude can be limited in the BRIGHTER menu. At
power-up, the magnitude value is at a very faint level:
+20.0.
You may want to adjust the magnitude level to a brighter
value, starting at perhaps the limiting visual magnitude of
your LX200, which is approximately 15.5 for the 16"
LX200. If you are taking astrophotographs, the limiting
magnitude is about 18.0. Sky conditions (haze, high
clouds, light pollution) also greatly affect the limiting