APPENDIX A: EQUATORIAL WEDGE
There are two equatorial wedges used on Meade LX200 telescopes. Please
read the section, below, that applies to your telescope.
1. 8" Equatorial Wedge (For 7" and 8" LX200)
The Equatorial Wedge permits use of the 8" LX200 telescope in an astronomical,
or "equatorial," mode. The wedge fits onto the field tripod,
described below, and accepts the base of the 7" or 8" LX200 fork
mount. See Fig. 8.
NOTE: The Meade equatorial wedge is designed solely for use in conjunction
with the Meade field tripod. The wedge should never be used without
the field tripod, e.g. by placing the wedge alone on a table top and then
mounting the telescope on the wedge. The 7" or 8" LX200, placed
onto the equatorial wedge alone without the field tripod attached to the
wedge may become seriously imbalanced, to the point where the telescope
may actually tip over.
The equatorial wedge for the 7" and 8" LX200 telescope is of
modern design, with several important features incorporated to simplify
and facilitate telescope operation. After using the wedge, you will find
that the functional design features included are of very significant value
in routine telescope operations. Features included are:
1. Attachment of the wedge to the field tripod by means of only one manual
knob.
2. Quick azimuth adjustment by loosening the manual knob as described above.
3. Bubble level for rapid tripod/wedge leveling.
4. Etched latitude scale for fast adjustment of the latitude angle.
To assemble the equatorial wedge, follow this procedure (note that all
required wedge hardware and manual knobs are shipped within the wedge carton):
1. The wedge consists of two basic parts: the wedge body and the tilt-plate,
as shown in Fig. 8. Attach the tilt-plate to the wedge body by threading
in the four knobs provided. Two knobs, with washers, should be used on
each side of the wedge body so that a total of 4 knobs attach the tilt
plate to the wedge body.
2. Place the wedge onto the field tripod with the central threaded rod
of the tripod fitting through the center hole in the floor of the wedge.
Thread the 2-1/2" diameter manual knob onto the threaded rod of the
tripod and firmly tighten the manual knob.
a. Azimuth Control
The Azimuth Control for the Meade Equatorial Wedge and Field Tripod is
shipped in a plastic bag and includes the following parts:
1. Azimuth Base (large U shaped piece of aluminum)
2. Azimuth Arm (small T shaped piece of aluminum)
3. 2 - Azimuth Knobs
4. 2 - 8-32 x 1/2" flat-head machine screws
5. 2 - 8-32 x 1" round-head machine screws
To attach the Azimuth Control to your wedge and tripod, follow these steps:
1. Remove the 4 set screws from the wedge and field tripod (which plug
the attachment holes) using a screwdriver.
2. Attach the Azimuth Arm to the Equatorial Wedge using the 2 ea. 8-32
x 1/2" flat-head machine screws.
3. Attach the Azimuth Base to the Field Tripod using the 2 ea. 8-32 x 1"
round-head machine screws.
4. Thread the two Azimuth Adjustment Knobs into the Azimuth Base, until
they just touch the Azimuth Arm.
The Azimuth control is now ready to use. To adjust in Azimuth, loosen the
3" central wedge knob. Rotate the wedge by using the two Azimuth knobs
in a push-pull manner. After positioning the wedge, tighten the central
wedge knob.
b. Deluxe Latitude Adjuster
The Deluxe Latitude Adjuster (DLA) attaches directly to the Equatorial
Wedge and permits very precise adjustments in latitude angle by the simple
turning of one knob.
The Equatorial Wedge for Meade 7" or 8" Schmidt-Cassegrain telescope
is shipped with the main crossbar of the DLA already installed. Loosen
the two socket-head screws that lock the main crossbar in place, to allow
the crossbar to rotate slightly if needed. Thread the long adjustment knob
(3, Fig. 14) into the main
crossbar and position the end of the adjustment knob into the cavity on
the underside of the Equatorial Wedge Tilt-Plate. Tighten the two socket-head
screws locking the main crossbar into place.
The DLA is now ready to use. To make fine latitude adjustments, follow
this procedure:
1. Slightly loosen the knobs (5, Fig.
8), on each side of the wedge.
2. Turn the DLA's adjustment knob (pressing against the bottom of the tilt-plate),
so that the tilt-plate moves in latitude angle.
3. Re-tighten the two knobs, which were loosened in step 1, above.
NOTE: When installing the tilt-plate to the wedge, note that it is a tight
fit and the sides must generally spread slightly to accept the tilt-plate.
If the main crossbar of the DLA is already tightened into place this will
inhibit your installation of the tilt-plate. You will therefore see that
by releasing the screws on the ends of the DLA crossbar your installation
of the wedge tilt-plate will be facilitated.
2. SUPERWEDGE (For 10" and 12"LX200)
The Superwedge permits use of the 10" and 12" LX200 telescope
in an astronomical, or "equatorial," mode. The wedge fits onto
the field tripod, described below, and accepts the base of the 10"
and 12" LX200 fork mount. See
Fig. 10.
NOTE: The Meade Superwedge is designed solely for use in conjunction
with the Meade field tripod. The Superwedge should never be used without
the field tripod, e.g. by placing the Superwedge alone on a table top and
then mounting the telescope on the wedge. The 10" and 12" LX200,
placed onto the Superwedge alone without the field tripod attached to the
wedge may become seriously imbalanced, to the point where the telescope
may actually tip over.
The Superwedge for the 10" and 12" LX200 telescope is of modern
design, with several important features incorporated to simplify and facilitate
telescope operation. After using the Superwedge for your telescope, you
will find that the functional design features included are of very significant
value in routine telescope operations. Some of these features include:
1. Attachment of the Superwedge to the field tripod by means of only one
manual knob. (For photographic applications with the telescope where extreme
steadiness is required, 3 additional hex-head screws are provided).
2. Quick Azimuth adjustment by loosening the manual knob as described above.
3. Bubble level for rapid tripod/wedge leveling.
4. Etched latitude scale for fast adjustment of the latitude angle.
5. Built-in latitude adjustment control.
To assemble the Superwedge, follow this procedure (note that all required
wedge hardware and manual knobs are shipped within the wedge carton):
1. Locate the two 8-32 nylon set screws on the rim of the tripod head and
remove them. Attach the tangent arm to the tripod using the supplied 8-32
X 1/2" socket cap screws. (See Fig. 11a.)
.
.
.
.
.
Grasping the 2 fork arms of the telescope firmly, with the power panel
towards you, place the telescope onto the tilt plate of the wedge by sliding
the knob (7" and 8" LX200) or screw (10" and 12" LX200)
into the slot at the top of the curved-end of the wedge tilt-plate.
Insert the 2 remaining knobs for the 7" and 8" LX200, or socket
screws for the 10" and 12" LX200, through the underside of the
tilt plate and into the underside of the drive base. Tighten down all 3
knobs or screws to a firm feel. Extreme force is not necessary in
this regard.
The telescope is now fully mounted onto the wedge and field tripod. Adjustments
in wedge latitude angle and/or azimuth orientation may be made with the
telescope in place. Further details on telescope polar alignment see Appendix
B: Equatorial Use.
4. Magnetic Compass (for 7", 8" Equatorial Wedge and 10",
12" Superwedge)
The magnetic compass helps the observer to set-up the telescope without
actually seeing the pole star Polaris. This allows setting up before dark
or in locations where the view of Polaris is obstructed. The magnetic compass
has an adjustment to compensate for the local angle of Magnetic Declination.
Note: Magnetic Declination is the difference between Magnetic North (which
the compass shows) and true north (where the telescope should be pointed).
Magnetic Declination should not be confused with the astronomical term
"Declination," which, when used with "Right Ascension,"
describes the celestial coordinate system.
a. Setting Magnetic Declination
In order to obtain an accurate reading using the compass, you must first
adjust for the Magnetic Declination for your location.
1. First, determine the Magnetic Declination in your area using the Isogonic
Chart (Fig. 15)
2. Squeeze the clear central vial with thumb and index finger of the left
hand.
3. With the right hand, rotate the outer dial until the orienting arrow
(the black arrow painted on the inside clear surface) is lined up with
the desired Magnetic Declination angle on the declination scale. Notice
that East Magnetic Declination is to the right of the "North"
position and West Magnetic Declination is left of the "North"
position. As an example, Fig. 16. shows the correct setting for 16 degrees
West Declination, which covers Providence, Rhode Island.
Figure
16. b. Compass Installation
The Magnetic Compass is now set for the correct declination angle. To
attach to the Equatorial Wedge, follow these steps:
1. Snap the Magnetic Compass into the 3" diameter wedge attachment
knob (after setting the Magnetic Declination as described above). Position
the compass into the knob so that the 360 degree location on the direction
scale (the "North" position) lines up with one of the nine points
of the knobs. (See Fig.
16.) Press the compass firmly into the knob.
2. Assemble the Equatorial Wedge onto the Field Tripod as described in
the Instruction Manual using the knob/compass combination to attach the
wedge to the tripod.
Figure
17. c. Finding True North
The Magnetic Compass is now ready to use. Just
follow these simple steps for a quick and easy azimuth alignment:
1. Loosen the knob/compass slightly. This allows for rotation of the Equatorial
Wedge under the knob/compass (Fig.
17). The magnetic pointing arrow will point to magnetic north.
2. Rotate the knob/compass so that the magnetic pointing arrow lies directly
over the painted black alignment arrow (painted on the bottom surface of
the compass, Fig. 18). The "North"
position on the direction scale (and the point on the knob/compass) now
point directly north.
3. Rotate the Equatorial Wedge in azimuth (without moving the knob/compass)
until the centerline of the wedge lines up with the point of the knob/compass
(Fig. 19). The centerline of the Equatorial
Wedge now falls directly on the true north line.
4. Tighten the knob/compass, locking the Equatorial Wedge into place.
The Field Tripod and Equatorial Wedge are now pointed directly toward celestial
north, without ever having seen the North Star.
2. Lining Up with the Celestial Pole
Objects in the sky appear to revolve around the celestial pole. (Actually,
celestial objects are essentially "fixed," and their apparent
motion is caused by the Earth's axial rotation). During any 24 hour period,
stars make one complete revolution about the pole, making concentric circles
with the pole at the center. By lining up the telescope's polar axis with
the North Celestial Pole (or for observers located in Earth's Southern
Hemisphere with the South Celestial Pole. See section G. Mode Functions)
astronomical objects may be followed, or tracked, simply by moving the
telescope about one axis, the polar axis. In the case of the Meade LX200
7", 8", 10", and 12" Schmidt-Cassegrain telescopes,
this tracking may be accomplished automatically with the electric motor
drive.
If the telescope is reasonably well aligned with the pole, therefore, very
little use of the telescope's Declination slow motion control is necessary--virtually
all of the required telescope tracking will be in Right Ascension. (If
the telescope were perfectly aligned with the pole, no Declination
tracking of stellar objects would be required). For the purposes of casual
visual telescopic observations, lining up the telescope's polar axis to
within a degree or two of the pole is more than sufficient: with this level
of pointing accuracy, the telescope's motor drive will track accurately
and keep objects in the telescopic field of view for perhaps 20 to 30 minutes.
Begin
polar aligning the telescope as soon as you can see Polaris. Finding Polaris
is simple. Most people recognize the "Big Dipper." The Big Dipper
has two stars that point the way to Polaris (see Fig.
21). Once Polaris is found, it is a straightforward procedure to
obtain a rough polar alignment.
To line up the 7", 8", 10" or 12" LX200 with the Pole,
follow this procedure:
1. Using the bubble level located on the floor of the wedge, adjust the
tripod legs so that the telescope/ wedge/tripod system reads "level."
2. Set the Equatorial Wedge to your observing latitude as described in
Appendix A.
3. Loosen the Dec. Lock, and rotate the telescope tube in Declination so
that the telescope's Declination reads 90°. Tighten the Dec. Lock.
Loosen the R.A. Lock, and rotate the Fork Arms to the 00 H.A. position
(See section G. Mode Functions) and initiate the POLAR align sequence on
the Keypad.
4. Using the Azimuth and Latitude controls on the Wedge, center Polaris
in the field of view. Do not use the telescope's Declination or Right Ascension
controls during this process.
At this point, your polar alignment is good enough for casual observations.
There are times, however, when you will need to have precise polar alignment,
such as when making fine astrophotographs or when using the setting circles
to find new objects (see Refined Polar Alignment).
a. If the star drifts South (or down), the telescope's polar axis is
pointing too far East (Fig. 22).
b. If the star drifts North (or up), the telescope's polar axis
is pointing too far West (Fig. 23).
4. Move the wedge in azimuth (horizontally) to effect the appropriate change
in polar alignment. Reposition the telescope's East-West polar axis orientation
until there is no further North-South drift by the star. Track the star
for a period of time to be certain that its Declination drift has ceased.
(Please note that Figs. 22, 23, 24, and 25 show the telescope pointed in
the 90 degree position, and not the 0 degree position that is required
for "Drift" method alignment. This is done to illustrate the
position of the pole star relative to the polar axis of the telescope.)
5. Next, point the telescope at another moderately bright star near the
Eastern horizon, but still near the celestial equator. For best results,
the star should be about 20° or 30° above the Eastern horizon and
within ± 5° of the celestial equator.
6. Again note the extent of the star's drift in Declination:
a. If the star drifts South, (or down) the telescope's polar axis
is pointing too low (Fig. 24).
b. If the star drifts North, (or up) the telescope's polar axis
is pointing too high (Fig. 25).
7. Use the latitude angle fine-adjust control on the wedge to effect the
appropriate change in latitude angle, based on your observations above.
Again, track the star for a period of time to be certain that Declination
drift has ceased.
The above procedure results in very accurate polar alignment, and minimizes
the need for tracking corrections during astrophotography.
2. The CNGC Catalog
You will notice that the Messier (M) objects, and the NGC objects have
been incorporated into the Meade Instruments CNGC listing. CNGC stands
for "Computerized New General Catalog of Non-Stellar Astronomical
Objects". The CNGC is an enhancement from the RNGC (Revised
New General Catalog) in many ways. Angular sizes are given in arc-seconds
on the CNGC listing, and in a convenient scaled format on the LX200
Keypad Display.
The complete CNGC contains 7840 objects most of which appear in
the RNGC (Revised New General Catalog) with
the same number. More than 400 objects were added to the RNGC to create
the CNGC. Most of these "should have been" in the RNGC
in the sense that they are bright and large enough to have been included.
The CNGC is enhanced from the RNGC in many ways. Angular sizes are
given in arc-seconds on the CNGC listing, and in a convenient
scaled format on the LX200 display. Magnitudes are given to .1 magnitude
where possible.
The coordinates in the CNGC listing are listed for the year 2000. The LX200
calculates object positions upon power up to the current date (as shown
on the time/date display). This makes the LX200 pointing more accurate.
Therefore, the CNGC listing and the LX200 display will not exactly agree
on object positions.
Objects have been assigned a "Visual Quality Rating", henceforth
called VQ. A large number of VQs have been obtained by observing the objects.
To make the VQs as useful as possible, all observations have been made
with the same telescope and eyepiece under substantially identical observing
conditions. Only for very small objects was a higher power eyepiece used.
Your "Visual Quality Rating" of a particular object will vary,
largely due to sky conditions.
If the object has been rated by observation, an upper-case character (ABCDEFG)
is used for the VQ on the CNGC listing. If the object has not been observed,
the VQ has been estimated by a computer program from the object type, size,
and brightness and the VQ is specified in lower-case characters (abcdefg).
The VQs for visually-rated objects are a considerably more consistent guide
to observability and appearance than either the computed VQs or an examination
of the type, magnitude, and size data.
All, or very nearly all, of the objects in the CNGC are visible with
the standard instrumentation and observing conditions used to obtain the
visual quality ratings. It is a good indication of what can be expected
with similar equipment by experienced deep-sky observers in excellent sky
conditions. Naturally smaller telescopes and/or less optimal observing
conditions will lower the apparent quality of all objects.
The following is a description of the format of the optional CNGC listing
for each object:
The following types are distinguished in the CNGC.
3. The Star Catalog
The STAR Catalog contains the 250 brightest stars (STAR 1 through STAR
250), 100 interesting double stars (STAR 251 through STAR 350), plus Sigma
Octantis, the southern pole star (STAR 351).
4. Select Star by Name
When selecting a star from the object library, any of the 33 stars listed
in the LX200 Instruction Manual can now by accessed by its name.
1. Press the STAR key. The Keypad display will show "STAR object:" on the first line and a blinking cursor on the second line.
2. To enter a Star by number, simply type in the star number and press ENTER, as described in the LX200 Instruction Manual.
To enter a Star by name, press the ENTER key. The Keypad display will show a new menu.
3. Select the NAME menu option by pressing the ENTER key.
4. Scroll through the list of Star names (using the PREV and NEXT keys) until the desired Star name is selected.
5. Press ENTER to select this Star.
5. The M Catalog
The M Catalog has been the benchmark deep-sky catalog for years. Recently
expanded to 110 objects, the M (Messier) catalog contains most of the best
deep-sky objects.
6. The Planets
The LX200 calculates the orbital positions of the eight major planets for
the current calendar date. To access a planet, use the STAR key and enter
the appropriate number as indicated below:
7. Other Databases
The other object catalogs are accessed through the CNGC key on the Keypad.
1. Press the CNGC key. The Keypad display will show "NGC object:" on the first line and a blinking cursor on the second line.
2. To enter a NGC object, simply type in the NGC number and press ENTER, as described in the LX200 Instruction Manual.
To enter an object from a different database, press the ENTER key. The Keypad display will show a new menu of the available databases.
3. Select the database from the menu by moving the arrow to the selection desired and pressing the ENTER key. Press MODE to exit the database menu.
4. The Keypad display will ask for the object number. Enter the object number desired and press ENTER.
The LX200 will "remember" the database you last accessed. Each
time you press the CNGC key, the same object database will be displayed
on the first line of the Keypad display. To change databases, press ENTER
to bring up the database menu.
The STAR databases are accessed by pressing the STAR key and following
the above steps.
Variable stars from the GCVS are entered using a six digit number. The
first two digits, refer to the constellation where the variable star is
located and is listed in the table below.
The next four digits are assigned sequentially within each constellation
according to the standard sequence of variable-star designations (R, S,
...).
Therefore, the first variable star in the constellation of Virgo would
be entered as: 860001.
Table
13: Constellation Codes
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