Go to ESO/Uppsala
This option is used when you want to recenter on a
galaxy by typing in its ESO (ESO/Uppsala) catalog
number.
When you select this option, you are asked for an ESO
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel.
An ESO designation consists of two numbers, separated
by either a space or a minus (-) sign. Sometimes a letter
is added.
Go to Galaxy
The Go to Galaxy menu (found withing the Go To menu)
provides assorted ways to find a galaxy:
Go to PGC (Principal Galaxy Catalog)
Go to UGC (Uppsala Galaxy Catalog)
Go to MCG (Merged Catalog of Galaxies)
Go to ESO/Uppsala (European Southern Observatory extension
to the UGC)
Go to CGCG (Catalog of Galaxies and Clusters of Galaxies)
Go to Markarian (Markarian catalog of active galaxies)
Go to Abell cluster (Abell catalog of clusters of galaxies)
Go to Zwicky cluster (Zwicky catalog of clusters of galaxies)
Go to galaxy name (such as Copeland's Septet, Leo A, etc.)
Go to Hickson (Hickson Catalog of compact groups of galaxies)
Go to Arp (Arp Catalog of Peculiar Galaxies)
go to galaxy name
This option is used when you want to recenter on a
galaxy by clicking on its common name.
Quite a few galaxies have, along with the usual
catalog number, a common name. For example, Centaurus
A is better known by that name than as NGC 5128; the
nearby galaxies Maffei I and II are better known by those
designations than by their PGC numbers.
When you select this option, you will see a list of
common galaxy names. If you click on one, you will
recenter on that object. You can also hit escape at that
point to cancel.
go to globular cluster
The Go to Globular Cluster option lists globular
clusters not found in the NGC and IC catalogs, such
as those in the Palomar and Terzan series. It also lists
objects such as 47 Tucanae and Omega Centauri, since
these objects are far better known by those names than by
their NGC numbers.
Go to GSC
This option is used when you want to recenter on a star
by typing in its GSC (Guide Star Catalog) area and
number.
When you select this option, you are asked for the
GSC identifier of the star on which you wish to recenter.
After you enter this, Guide will recenter on the star.
You can hit escape at any point in this process to cancel.
The identifier consists of two numbers: a zone ranging from
1 to 9537, and a number designating the specific star in
that zone. This second number can range up to about 12,000.
Go to HD
This option is used when you want to recenter on a star
by typing in its HD (Henry Draper) catalog number.
HD numbers range from 1 to 359083.
When you select this option, you are asked for an HD
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel.
Go to Hickson
This option is used when you want to recenter on a
galaxy by typing in its Hickson catalog number.
When you select this option, you are asked to enter
a Hickson catalog number. If you enter one, you will
recenter on that object. You can also hit escape at that
point to cancel.
Go to Hipparcos
This option is used when you want to recenter on a star
by typing in its Hipparcos catalog number.
When you select this option, you are asked for an
Hipparcos catalog number. If you enter one, you will
recenter on that object. You can also hit escape at that
point to cancel.
Go to IC
I
This option is used to find an IC object and recenter
on it. IC numbers range from 1 to 5386.
When you select this option, you are asked for an IC
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel.
You can reach this option at any time by hitting 'I',
unless that key is already in use by the menu.
Go to LBN
This option is used when you want to recenter on a
nebula by typing in its Lynd's Bright catalog number.
When you select this option, you are asked for a
Lynd's Bright Nebulae catalog number. If you enter one,
you will recenter on that object. You can also hit escape
at that point to cancel.
Go to Mark
{
This program comes with some preset marked locations.
When you click on this option, you'll get an alphabetized
list of all marked locations presently available. You can
click on any of them and the program will go to that mark
location and settings.
If you want to add a mark, you can use the Save a Mark
option.
This item can be reached at any time via the {
hotkey; or, you can reach it from within the File menu.
Go to Markarian
This option is used when you want to recenter on a
galaxy by typing in its Markarian catalog number.
When you select this option, you are asked for a
Markarian catalog number. If you enter one, you will
recenter on that object. You can also hit escape at that
point to cancel.
Go to MCG
This option is used when you want to recenter on a
galaxy by typing in its MCG (Morphological Catalog of
Galaxies) number.
When you select this option, you are asked for a UGC
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel.
An MCG number consists of three parts: a starting
number ranging from -5 to 15, a second number from 0
to 60, and a third from 0 to 214. (Sometimes a letter
is added to this.) You can separate the numbers by spaces
or by minus (-) signs, as desired.
Go To menu
ALT-G
The Go To menu lists all the methods available to find
("go to") a given object or coordinates. In "normal" star charting
mode, the options available are:
Messier
NGC
IC
Horizon dialog
Go to Satellite
Go to planet
Go to planet feature
Go to comet
Go to asteroid
Go to star
Go to nebula
Go to open cluster
Go to globular cluster
Go to constellation
Go to galaxy (this includes clusters of galaxies)
Go to coordinate
Go to .TDF object
If you have used the Show Eclipse feature, so that charts of the
Earth are shown instead, the following functions will be given in this menu:
Go to Country
Go to City
Go to Messier
M
This option is used to find a Messier catalog object
and recenter on it. Messier numbers range from 1 to 110.
When you select this option, you are asked for a
Messier catalog number. If you enter one, you will
recenter on that object. You can also hit escape at
that point to cancel.
You can reach this option at any time by hitting 'M',
unless that key is already in use by the menu.
Go to Nebula
The Go to Nebula menu (found withing the Go To menu)
provides assorted ways to find a nebula:
Go to Sharpless (Sharpless catalog of bright nebulae)
Go to LBN (Lynd's Bright Nebulae catalog)
Go to PK (Perek-Kohoutek, or "Strasbourg" catalog of
planetary nebulae)
Go to Van den Bergh
Go to Barnard (Barnard's catalog of dark nebulae)
Go to nebula name (such as Veil, Trifid, Helix, etc.)
Go to Abell planetary (Abell's catalog of planetary nebulae)
Go to Nebula name
This option is used when you want to recenter on a
nebula by clicking on its common name.
Quite a few nebulae have, along with the usual
catalog number, a common name. For example, M-57 is
better known as the Ring Nebula, and NGC 7000 is better
known as the North American Nebula.
When you select this option, you will see a list of
common nebula names. If you click on one, you will
recenter on that object. You can also hit escape at that
point to cancel.
Go to NGC
N
This option is used to find an NGC object and recenter
on it.
When you select this option, you are asked for an NGC
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel. NGC numbers range from 1 to 7840.
You can reach this option at any time by hitting 'N',
unless that key is already in use by the menu.
Go to NSV
Ctrl-N
This option is used when you want to recenter on a star
by typing in its NSV (New Suspected Variable) catalog
number. NSV numbers range from 1 to 14811.
When you select this option, you are asked for an NSV
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel.
You can select this option at any time by using the
Ctrl-N hotkey.
Go to Open Cluster
The Go to Open Cluster option lets you find an open
cluster from any of over 40 catalogs, such as the Stock,
Berkeley, Trumpler, and Melotte catalogs. It first asks
that you specify a catalog; then, it asks that you
provide the number of the object in the catalog. Guide
will then recenter on that open cluster.
Go to PGC
This option is used when you want to recenter on a
galaxy by typing in its PGC (Principal Galaxy Catalog)
number.
When you select this option, you are asked for a PGC
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel.
Go to PK
This option is used when you want to recenter on a
nebula by typing in its PK (Perek-Kohoutek) catalog
number.
When you select this option, you are asked for a PK
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel.
A PK designation consists of two numbers, separated
by either a plus (+) or minus (-) sign. The numbers are
actually rough galactic coordinates for the object.
Go to Planet
=
When you select this option, you will see a list of
the planets that this program knows about, as well as
the Moon, Sun, and the moons of Jupiter and Saturn.
Click on one, and Guide will recenter on that object.
You can reach this dialogue box at any time by hitting
the = hotkey.
Go to planet feature
If you have zoomed in on a planet or natural satellite, you can use the
Go to Planet Feature option to get a list of features that would currently
be on-screen. Select one, and Guide will recenter the chart on that
feature.
Remember that only features currently on-screen, and therefore on the
side of the planet currently facing you, will be listed. An object on
the lunar farside, for example, is not going to be listed unless your
home planet is someplace other than Earth.
Go to PPM
This option is used when you want to recenter on a star
by typing in its PPM catalog number.
When you select this option, you are asked for a PPM
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel.
Go to SAO
This option is used when you want to recenter on a star
by typing in its SAO catalog number.
When you select this option, you are asked for an SAO
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel. SAO numbers range from 1 to 258,997.
Go To Satellite
The Go to Satellite option in the Go To menu provides a way to
find an artificial satellite from its name. When you click on this
option, Guide will prompt you to enter the satellite name. You
usually don't have to enter the complete name; for example, "Mir
Com" will be enough to get the "Mir Complex".
Go to Sharpless
This option is used when you want to recenter on a
nebula by typing in its Sharpless catalog number.
When you select this option, you are asked for a
Sharpless catalog number. If you enter one, you will
recenter on that object. You can also hit escape at
that point to cancel.
Go to Star
The Go to Star menu (found withing the Go To menu)
provides assorted ways to find a star.
Go to Bayer/Flamsteed (such as Alpha Cen, 61 Cyg, etc.)
Go to Yale (BSC) (also known as the HR catalog)
Go to SAO (Smithsonian Astrophysical Observatory) star
Go to PPM (Position & Proper Motion catalog) star
Go to HD (Henry Draper catalog) star
Go to GSC (Guide Star Catalog) star
Go to Common Star name (such as Vega, Rigel, etc.)
Go to Variable star (such as SS Cyg, Z Cam, etc.)
Go to NSV (New Suspected Variables catalog) star
Go to Double Star (such as the Struve, Aitken, etc.
catalogs)
Go to Supernova (in other galaxies, such as 1987A,
1993J, etc.)
Go to Durchmusterung (DM) star; includes the BD,
SD, CPD, and CD catalogs
Go to Hipparcos star
Nearby star
Go to Supernova
This option is used when you want to recenter on a star
by typing in its supernova designation.
When you select this option, you are asked to enter a
supernova designation, such as 1993J or 1885A. When you
have done so, Guide will recenter on that star.
Go to UGC
This option is used when you want to recenter on a
galaxy by typing in its UGC (Uppsala General Catalog)
number.
When you select this option, you are asked for a UGC
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel.
Go to Van den Bergh
This option is used when you want to recenter on a
nebula by typing in its van den Bergh (vdB) catalog
number.
When you select this option, you are asked for a
van den Bergh catalog number. If you enter one, you will
recenter on that object. You can also hit escape at that
point to cancel.
Go to Variable
CTRL-V
\
This option is used when you want to recenter on a
variable star by typing in its variable star designation.
(Examples are R CrB, SS Cyg, VZ Cam, and V1016 Ori.)
When you select this option, you are asked to type in
a variable star designation. If you enter one, you will
recenter on that object. You can also hit escape to
cancel. If the constellation or star does not exist, you
will get a message to that effect and will stay where you
are.
You can reach this option at any time with the Ctrl-V
or \ hotkeys.
Go to Yale (BSC)
This option is used when you want to recenter on a star
by typing in its HR (Bright Star) catalog number.
When you select this option, you are asked for an HR
catalog number. If you enter one, you will recenter on
that object. You can also hit escape at that point to
cancel. HR numbers range from 1 to 9110.
Go to Zwicky cluster
This option is used when you want to recenter on a
cluster of galaxies by typing in its Zwicky catalog
number.
When you select this option, you are asked for a
Zwicky catalog number. If you enter one, you will
recenter on that object. You can also hit escape at that
point to cancel.
GPO-V
This plate in the GSC was taken using the GPO (Gran
Prism Objectif) telescope at La Silla, using IIaD
emulsion and GG495 filter.
Great Red Spot
GRS
GRS longitude
Alt-/
The Great Red Spot (GRS) on Jupiter is an enormous
circular storm, much like a hurricane. It has existed at
least since telescopes were first pointed at Jupiter, almost
400 years ago. It has varied in size and color over the years,
and at times, has almost vanished from sight. In the late
Summer of 1996, the GRS has been pale orange- tan, darkened
toward the southern edge.
When you click for "more info" on Jupiter, the time of
the next transit of the Great Red Spot (that is, the time
at which it will next be well-placed for observing) will
be given. It will be reasonably well-placed for about
50 minutes before and after that time.
Also, there is a command to make a list of GRS "transits"
in the Tables menu.
Like all cloud features, the GRS moves a little; Guide
assumes a Jupiter System II longitude of 66 degrees. In
Windows Guide, you can change the GRS longitude by
right-clicking on Jupiter, then on "Display", then on
"Options...". The Options dialog for Jupiter includes a line
for the GRS longitude. The value you enter here will be used
to draw the GRS in the correct part of the chart, and in
computing transit times.
In DOS, you can change the GRS longitude with the Alt-/ hotkey.
grids
Grids are the lines indicating intervals of right
ascension and declination that are common to many star
charts. You can adjust their spacing and turn them on
and off within the measurements dialog.
Group Membership
Many stars appear in groups, some not obvious from the
viewpoint of the Earth. These groups usually share a
common part of the sky and move in a common direction.
The Bright Star catalog will sometimes remark on a star's
Group Membership in the Remarks.
GSC
Guide Star Catalog
The Hubble Guide Star Catalog is a catalog of about 18
million stars that was made for the purpose of providing
precise pointing for the Hubble Space Telescope. This
catalog contains most of the stars down to magnitude 15.
It has many more stars than the SAO and Bright Star
catalogs, but it doesn't have as much detail about each
star. In fact, about the only information it contains on
each star is its magnitude and position, plus a guess
as to whether the object is a star, galaxy, or non-star
(meaning an asteroid, comet, scratch, or something
else).
If you know an object's GSC area and number (its GSC
identifier), you can recenter on it using the Go to GSC
option in the Go to Star menu in the Go To menu.
GSC identifier
GSC #
The Hubble GSC specifies each object by two numbers.
It first divides the sky into 9537 tiles, each with
roughly the same number of stars. (This means that tiles
tend to be smallest where stars are densest.) Any star in
the catalog can be described by its region and number
within that region. Combined, the two form a catalog
number, the GSC identifier for the star.
When you click on a GSC star, its identifier is shown
right away, and is shown again when you "click for more
info." If you already know a star's GSC identifier and
want to find that star, you can do so using the Go to
GSC option in the Go to Star menu under the Go To menu.
GSR
galactic standard of rest
When given a galaxy RV (radial velocity), it's
important to know from what point it is measured. A logical
point to use is the center of our own galaxy, the GSR or
galactic standard of rest. One can also use the sun or the
3K background for a point of reference.
GUIDE
Project Pluto
Help with GUIDE is available from:
Project Pluto
168 Ridge Road
Bowdoinham, Maine 04008
Telephone (207) 666 5750
(800) 777 5886 (1-800-PRPLUTO)
Fax (207) 666 3149
Internet pluto@projectpluto.com
http://www.projectpluto.com
Support is available from 8 AM to 7 PM Eastern time
(13.00 to 24.00 UT).
Version 1.0 of GUIDE was released in April 1993;
version 2.0, in July 1993; version 3.0, May 1994;
version 4.0, July 1995; version 5.0, August 1996;
version 6.0, September 1997; and version 7.0,
November 1998.
You are running the 4 September 1999 version.
H alpha
H beta
The H alpha and H beta lines are emitted by hydrogen
atoms whose electrons have been bumped into a high-energy
state, and have jumped back down to a lower-energy state.
They are the first two members of the Balmer series of
hydrogen spectrum lines.
Quite a few filters have been produced that allow only
light close to the H alpha frequency to pass. The
advantage of such a filter is that when used to observe
the Sun, certain features (such as prominences) can be
much more readily seen.
hatches
Hatches are lines on the edge of the screen showing
intervals of right ascension and declination. Common on
most star charts, this program lets you turn the display
of hatches on or off and to adjust their spacing within
the measurements dialog.
HD
Henry Draper
The Henry Draper, or HD, catalog is a commonly
used catalog of stars. It includes spectral types and
positions for most stars down to about magnitude 8. It
was compiled early in this century; it does not have
very good positional data (which is why Guide doesn't
show positions from this catalog), but it is often the
only available source of spectral type information.
Hebrew calendar
The Hebrew calendar is the official calendar of Israel and of the
Jewish faith.
Like the Chinese calendar, the Hebrew calendar is a lunisolar
calendar. As with all lunisolar calendars, the rules of the Hebrew
calendar are somewhat complex. A year can have 12 or 13 months; in a
13-month "leap" year, the extra month of Adar II is inserted in the
middle of the year. Seven such months are inserted in a 19-year cycle.
The result is that there are 12*19+7=235 months every 19 years; it
so happens that 235 lunations is very close to 19 solar years, allowing
the Hebrew calendar to match both cycles quite well.
An "ordinary" 12-month year contains 354 days; a "leap" 13-month
year contains 384 days. But each variety can be extended or shortened
by one day, resulting in "complete", "regular", and "deficient"
years! Here is a table of the months and their lengths, in each of
the resulting six varieties of a year:
Ordinary Leap
Defic Regul Compl Defic Regul Compl
30 30 30 30 30 30 Tishri
29 29 30 29 29 30 Heshvan
29 30 30 29 30 30 Kislev
29 29 29 29 29 29 Tevet
30 30 30 30 30 30 Shevat
29 29 29 30 30 30 Adar
-- -- -- 29 29 29 Adar II
30 30 30 30 30 30 Nisan
29 29 29 29 29 29 Iyar
30 30 30 30 30 30 Sivan
29 29 29 29 29 29 Tammuz
30 30 30 30 30 30 Av
29 29 29 29 29 29 Elul
--- --- --- --- --- ---
353 354 355 383 384 385
Notice that, in leap years, the extra month of Adar II is inserted
and a day is added to Adar. In deficient years, a day is removed
from Kislev; in complete years, one is added to Heshvan.
By allowing for six different lengths of the year, the Hebrew
calendar can satisfy several design constraints. It can have months
that match the lunar cycle with great precision. It can also prevent
the holy day of Hoshana Rabba (Tishri 21) from occurring on the
Sabbath (Saturday), and Yom Kippur (Tishri 10) from occurring on the
day before or after the Sabbath. (To accomplish that, it is necessary
to have Tishri 1 occur on a Monday, Tuesday, Thursday, or Saturday.)
The years are counted from the Era of Creation, or "Era Mundi".
In this system, 1 Tishri 1 A.M. ("Anno Mundi", or "Year of the World")
corresponds to -3760 October 7 (in the Julian calendar).