More Uses for Your Timex/Sinclair 1000: Astronomy On Your Computer, by Eric Burgess, F.R.A.S. and Howard Burgess, Sybex Inc., 176pp., $8.95.
If the recent flights of the space shuttle have sparked your interest in astronomy then this might be the book you’ve been waiting for. More Uses for Your Timex/Sinclair 1000: Astronomy On Your Computer, is a collection of twenty programs dealing with amateur astronomy. The programs are quite varied, ranging from the EASTR program which calculates the date of Easter Sunday for any year, to the CONST program which randomly selects a constellation for display and gives you a chance to identify it. All the programs in this book require a TS1000 or a ZX81 with 16K RAM.
The book is divided into four sections. The first section deals with time and dates and the conversions between them. The second section is comprised of four programs dealing with the moon. The third section will help you learn your way around the planets and the fourth section contains three general purpose programs. I’ve entered three or four programs and all have performed as expected. The listings are lengthy but appear to be accurate. All the programs include a sample display so it is easy to check your program for accuracy.
Of the programs that I have used, the SKYPT program has been the most rewarding. SKYPT (for Skyplot) plots the position of the visible planets, the sun, and the moon for any date, time, and location of your choice. When you RUN the program the prompts will ask you for the necessary information such as the date, the time, the time zone and whether or not you wish to change the longitude and latitude. (The authors do note that this program should not be expected to run accurately at latitudes exceeding 85 degrees north and south.)
The following prompt will then ask you to choose a horizon centered on north, south, east or west. Now the fun begins! At the bottom of your screen the program generates an artificial horizon that makes excellent use of the Sinclair graphics. Next the program begins to plot the sun, the moon, and the planets. The planets are identified by various letters of the alphabet and other characters. (See figure 1.) On the right of the display the elevation in degrees is shown and at the top of your screen the date, the local time, and the location is printed. Overall the screen display is quite pleasing and easy to understand. If you have a Sinclair or Timex printer the screen can be copied (using the Sinclair COPY command) by answering the prompt at the bottom of the screen. (See figure 2.) The SKYPT program alone is well worth the price of the book.
FIGURE 1
PLANETS ETC. ARE IDENTIFIED AS... SUN....... O MERCURY... + VENUS..... V MARS...... M JUPITER... J SATURN.... S URANUS.... U NEPTUNE... N PLUTO..... P MOON NEAR FULL O BEFORE FULL ) AFTER FULL (
FIGURE 2
In general the programs are aimed at two types of astronomers, armchair astronomers and amateur astronomers. Armchair astronomers being those without telescopes and amateur astronomers being those who have telescopes. For amateur astronomers some of the programs contain information that will be useful for the setting of circles on equatorially mounted telescopes.
The authors point out that some of the programs that complement each other can be merged, the RADEM program and the RADEC are good examples. The RADEM program finds the right ascension and declination (position) of the moon and the RADEC program finds the right ascension and declination for all of the planets. The authors suggest that the program lines in the RADEM program be keyed in at higher line numbers and used as a subroutine for the RADEC program. Although I have not tried this I believe it should work as neither one of the program listings is excessively long.
If you have more than a passing interest in astronomy or if you are looking for a new way to use your TS1000 or ZX81, then this is a book to buy. The programs in Astronomy On Your Computer will give you many hours of pleasure under the summer skies.