Dear User,

VSTAR is a very simple program, a tool which does only one thing: it goes through the validation file and extracts lines which satisfy
one of three very simple criteria:

a. the star is brighter than given value at maximum and minimum, and, at the same time, has amplitude greater than some limit. 
b. the star in question is within a given declination window 
c. the star in question is within a given right ascension window


I did not bother to program simultaneous search in several of these parameters. So, first select stars according to one criterium, then simply rerun the program on
the newly created file and ask more... The program is written simply, and without any error checking, so you have to think about what you enter. The computer will
do the rest... One more comment: the program assumes that the information it seeks is at particular place in line (for instance the first two characters in the
line represent hours of rectascension (OK OK, they are part of the star designation, and correspond to year 1900, but are sufficient for the purpose...). So, if
AAVSO (or you, intentionaly or unintentionaly) changes this (for example by unintentionaly typing a blank at the beginnig of the line) the program will either
break with some sort of run-time error (like this would help you anyhow) or the output will be garbled. In such a case please check the input file, and then the
values you entered in the program...

I wrote this program to help me select stars for observing. Here, I feel limited by exactly the three parameters listed above. First, my scope is small, and my sky
quite poluted, so I need bright stars. Second, my balcony is not rotatable, so I see a slice of the sky roughly from SE to SW (which requires selection in RA) and
only up to near zenith, which for me translates in a slice of sky between DEC -30 and about +30, where I can observe. One thing that VSTAR can not do is to tell
you if for the particular star there is an AAVSO chart or not. For this, you will have to search the CD, or better, the AAVSO site. The search in coordinates is
not very sophisticated, as its main purpose is to reduce output file to a manageable size. You can then easily select manually whatever you want from it. Especialy
in RA, only full hours are taken into account, and full degrees in DEC. Even with such a crude selection, the list I get is compact enough that I can decide myself
which stars I will observe and which not...

When you start the program, it will ask you for the name of the input file (the file in which you will search for whatever you like). I usualy make a copy of the
first half of the validation file for this. This is the part of the file in which the stars are sorted according to designation, which at the same time corresponds
to RA and DEC of the year 1900. The second part of the validation file is not needed, and will puzzle the serch program, so cut it out. Note that the file name and
extension must satisfy the old MS-DOS name convention, i.e. the file name can be up to 8 characters long, and extension up to three.

You will then have to enter the name of the output file, in which the results of the search will be saved. Again, max. 8+3 characters. If you "hit" an existing
name, you will be warned, but when you say "Y" to overwrite, the old one is gone, so be carefull!

Now something strange will be required of you: to enter the number of comment lines at the beginning of the validation file. This is because these lines will be
skipped in search, but will be copied to output file. When you later open the output file, you will be reminded on the original file from which the data were
taken. Also, the program will write the search criteria you chose into the output file, producing a few more comment lines. The output file is a simple ASCII file,
so you can enter your comments using any ASCII file editor you like (Notepad in Windows, for example). The validation file from AAVSO CD V1 which I use has 13
comment lines at the beginning. If you are not sure, open the file with a text editor and count...

Note that some comment lines will be added to the output file, sou if you run the program again over it, count the total of comment lines before doing it.

Now, you have to choose how will you search the file. You have three options:


a. Extract all stars that are brigter than given magnitude in minimum and in maximum (diferen magnitudes, of course) and with amplitude larger than whatever you
want to have! Enter all magnitudes with a decimal point! When you enter all three values, the program will do its job and tell you when it is finished. If you see
anything else than DONE! written on the screen, something has gone wrong. Sorry, no help here, either you entered something that program does not understand, or
there is something in the input file that puzzles it.


b. Extract all stars that are within given declination window. Only full degress are taken into account, so do not bother to enter decimals. As usuall, north is +
and south -....

c. Extract all stars that are within given RA window. Here only full hours are looked at, so again, do not bother to enter more...


Happy searching!


Zeljko Andreic (AZE) 
andreic@rudjer.irb.hr