Software

Other Software and Utilities


This section describes miscellaneous software, such as a spreadsheet program (20/20), a calculator (CALC), and a program for printing sky plots (FINDER).

20/20

20/20 is a spreadsheet program available on KEPLER and DEVVAX. It works much like Lotus 1-2-3 or other PC spreadsheets and is useful for forecasting and planning.

Startup:

To start 20/20, you would type the following command:

$ S2020
You will be prompted for a terminal type. Most users will want to specify either VT100 or VT220, although there are more then 50 valid terminal types recognized by the program, including Tektronix and Wyse terminals. A list of supported terminal types can be seen by typing ? in response to the terminal type prompt.

Basic Commands:

Once you're in 20/20, commands are specified by pressing the slash key (/) (just as you would in Lotus). Available commands are listed across the top of the screen and can be selected by pressing the first letter of the command (or enough letters to make the command unambiguous). Figure 7.1 shows a sample of a 20/20 session.



Figure 7.1: Sample 20/20 Spreadsheet

Limited help is available from the system level by typing:

$ HELP 2020
Additional help is available from within the program by typing /H. A reference copy of the 20/20 users manual is available in the Science Software Support Office.

CALC

The VMS CALC utility emulates a desktop calculator. Arithmetic expressions are evaluated much as they would be in FORTRAN, with calculations performed on either 4-byte integers or 8-byte real values. Operators are evaluated using FORTRAN precedence rules. Variables can be used, but are limited to a single alphabetic character. It is also possible to create a file containing CALC commands. The most common use of CALC is to enter arithmetic expressions on a single line, and then pressing Return to end the line. When you're finished calculating, type *E or *S.

Variables:

Variables can be used to retain calculated values for later use. Variables consist of a single letter, and I-N can only be used to store integer values, while A-H and O-Z can be used for real values. Variables are assigned using FORTRAN-like syntax. For example, the following command could be used to assign a value to the variable I.

I=2**10-1.

Functions:

A variety of commonly-used mathematical functions are recognized by CALC; these functions are described in the following table:

Table 7.2: CALC Functions

Commands issued to CALC (that are not part of the expression to be evaluated) are preceded by an asterisk (*). For example, *@filename, which reads in a text file composed of valid CALC expressions. Additional arguments are possible, and these are explained in the online help.

FINDER

FINDER is a program, available on the Science Cluster, for producing laser printer plots of overlays on a user-specified scale (usually Palomar Sky Survey) covering an area of 1 square degree about a specified position. When the plotted symbols on an overlay are aligned with the star images on a plate, the tick marks in the center of the overlay will indicate the position of the specified coordinates with an accuracy of about +/- 8.5 arcseconds.

FINDER applies precession correction to input data and indicates the Sky Survey plate on which the specified position appears. Proper motions of the finder stars are considered when making the finder plots. FINDER also produces a list giving the approximate X,Y positions (relative to one reference star) of all reference stars and objects in the search area.

Instructions for setting up and using FINDER is available in Chapter 5 of the STScI Software Users Guide.

StarView

StarView is the user interface to the HST data archive. Three versions are available: a distributed version, one for character cell terminals, and another for X-windows.

The X-windows version is started by typing the command:

$ xstarview
The character cell version is started by typing the command:

$ starview 
More information is available in the HST Archive Primer and the HST Archive Manual. These are available outside room S210. If you have problems using StarView, send e-mail to ARCHIVE.

20/20
Startup:
Basic Commands:
Figure 7.1: - Sample 20/20 Spreadsheet
CALC
Variables:
Functions:
Table 7.2: - CALC Functions
FINDER
StarView

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