Leisure Time LX20 - Manual (Page 21)

menu selection, the OBJECT INFORMATION menu
selection, or the FIELD menu selection.
4. PARAMETERS: It is here that you can edit the Press ENTER
to find eight options which can be reviewed by scrolling
through this menu selection using the PREV or NEXT key.
To edit an option, move the arrow to the desired option and
press and hold ENTER until a double beep is heard and a
blinking cursor appears (except in the BETTER option)
Where numerical values are to be input, simply type them in
from the keypad. If you make a mistake, you can move the
cursor backward using the W key, then re-enter the data. To
exit to the main option menu, press the ENTER key once
again. A description of the eight options and how to set them
is below:
a. TYPE GPDCO: This menu file option allows you to
select the type of CNGC objects that you wish to locate.
GPDCO represent:
OBJECT SYMBOL LEGEND
SYMBOL DESCRIPTION
G GALAXIES
P PLANETARY NEBULAE
D DIFFUSE NEBULAE
C GLOBULAR STAR CLUSTERS
O OPEN STAR CLUSTERS
Initially, the blinking cursor appears over the G symbol.
If you decide not to look for galaxies, press NEXT and
the symbol will change from an upper case letter (G) to
a lower case letter (g), to deselect the GALAXIES
category. If you wish to leave GALAXIES selected,
then 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.
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.
b. BETTER: The BETTER menu file option allows you to
define the visual object quality range. At power up, the
range is set at the bottom of the scale on VP, when
using the START FIND menu selection, it will select all
objects that are very poor through super or what could
be considered an "ALL" setting. The object quality
symbols are:
QUALITY SYMBOL LEGEND
SYMBOL DESCRIPTION
SU SUPER
EX EXCELLENT
VG VERY GOOD
G GOOD
FR FAIR
PR POOR
VP VERY POOR
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 will now select
objects that look Very Good through Super.
c. HIGHER: The Higher menu file option sets the horizon
setting for the telescope. At power up, the setting is 00
degrees, which assumes that you have an unobstructed
line-of-site to the horizon in every direction. If, however,
there are things obstructing a level horizon, or if the sky
quality is poor due to haze or light pollution, you can set
an artificial horizon level so that your LX200 will not try to
Enter the number of degrees above the horizon that
will clear the obstructions in the sky. To roughly judge
how many degrees the obstruction is taking up of the
sky, merely hold your fist at arms length. Each fist
diameter is approximately 5 degrees. So, if a tree is
three fists high, you would make a setting of 15 degrees
in the HIGHER setting. Once the setting is finalized,
press ENTER.
d. LOWER: The LOWER menu file option sets the zenith
limit setting for the telescope. At power up, the setting is
90 degrees, 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.
e. 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
CCDcameras. Enter the new value in arc minutes,
then press ENTER to exit to the option file.
f. SMALLER: This menu option is the upper size object
limit. At power up the setting is for 200 arc minutes or
3.33 degrees. 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.
g. BRIGHTER: The lower brightness limits based on
stellar magnitude can be limited in the BRIGHTER
menu. At power up, the magnitude value is set to a
very faint level of +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
also greatly affect the limiting magnitude due to
atmospheric haze, high clouds, light pollution, or
combinations thereof.
h. FAINTER: The upper level of brightness may also be
adjusted with the FAINTER menu file option, although
you may find few applications for limiting it to a lower
value.
i. RADIUS: The RADIUS value sets the boundaries of
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find objects below your setting.