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Proposal Planning Toolkit |
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Proposal Planning Toolkit: Precess Help
Note: Cookies must be enabled in your browser to run Precess.
A future release may eliminate this requirement.
Input Coordinates
The user may enter the input coordinates or resolve a Target Name
using the Resolve Name button.
Coordinate System
Select the coordinate system to convert from/to.
Precess supports the following choices:
- Equatorial(B1950) - Equatorial w/ Besselian epoch B1950
- Equatorial(J2000) - Equatorial w/ Julian epoch J2000
- Equatorial(Xxxxx) - Equatorial w/ specified Besselian or Julian epoch
- Galactic - Galactic
- Ecliptic(B1950) - Ecliptic w/ Besselian epoch B1950
- Ecliptic(Bxxxx) - Ecliptic w/ specified Besselian epoch
- (CONVERT "TO" ONLY) Constellation - Returns the constellation
located at the given input position
Note about Ecliptic: Precess does not allow conversions from one
Ecliptic system to another Ecliptic system. The GUI therefore will
allow Ecliptic to be in either the Input list or the Output list,
but not both at the same time.
Equinox
Specify the epoch. This is enabled only if the selected
Coordinate System is Equatorial(Xxxxx) or Ecliptic(Bxxxx).
Coordinates
Input a set of coordinates in the format of the
selected coordinate system or resolve a target name which will
set the RA/Dec coordinates in J2000.
The supported coordinate ranges are listed below.
- EQUATORIAL - RA
- Right Ascension, given in either sexagesimal or
decimal format. Sexagesimal values are specified as "hh mm [ss[.ss]]"
(that is, hours and minutes are required, seconds and fractions of
seconds are optional).
The range for RA is:
Sexagesimal 00 00 00.00 to 24 00 00.00
Decimal 00.00 to 360.00
- EQUATORIAL - Dec
- Declination, given in either sexagesimal or
decimal format. Sexagesimal values are specified as "sdd mm [ss[.ss]]".
The range for Dec is:
Sexagesimal -90 00 00.00 to 90 00 00.00
Decimal -90.00 to 90.00
- GALACTIC - L2
- Longitude, given in either sexagesimal or decimal
format. Sexagesimal values are specified as "hh mm [ss[.ss]]". The
range for L2 is:
Sexagesimal 00 00 00.00 to 24 00 00.00
Decimal 00.00 to 360.00
- GALACTIC - B2
- Latitude, given in either sexagesimal or decimal
format. Sexagesimal values are specified as "sdd mm [ss[.ss]]". The
range for B2 is:
Sexagesimal -90 00 00.00 to 90 00 00.00
Decimal -90.00 to 90.00
- ECLIPTIC - EL
- Ecliptic Longitude, given in either sexagesimal or
decimal format. Sexagesimal values are specified as "hh mm [ss[.ss]]".
The range for EL is:
Sexagesimal 00 00 00.00 to 24 00 00.00
Decimal 00.00 to 360.00
- ECLIPTIC - EB
- Ecliptic Latitude, given in either sexagesimal or
decimal format. Sexagesimal values are specified as "sdd mm [ss[.ss]]".
The range for EB is:
Sexagesimal -90 00 00.00 to 90 00 00.00
Decimal -90.00 to 90.00
Target Name
Enter a valid target name and click the Resolve Name button.
This will query the catalog[s] specified in the
Name Resolver field.
If one, and only one entry is found, the coordinates will be
displayed in J2000. If no entry is found or more than one entry
is retrieved, the user will be asked to modify the Target Name
and try again.
Name Resolver
Name of the service or services that will be used to resolve
the target name when the Resolve Name button is pressed. The
services will be chosen in the specified order. For example,
"NED/SIMBAD" will first search for the target name in NED and
then, if the name was not found, in SIMBAD.
Constellation Output
The output is the constellation in which the given input
position lies. Positions are precessed to B1875.0 and compared with
the Delporte (1935) constellation definitions.
Output Format
The output is provided in two formats.
- Sexagesimal: hh mm ss.ss & sdd mm ss.ss
- Decimal: ddd.dddd & sdd.dddd
For online support please contact the CXC Helpdesk
Last modified:
07/16/08
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