ETB editing/minor problems/A2.0/eclipses

Bill J Gray May 27, 2003

Hi folks,

Oliver's post sums up the method nicely. The only thing I'd add
is to mention that editing 'events.dat' is sufficient for getting rid
of the CD-based event lists. You don't actually _need_ to delete
other files, because once they are no longer listed in 'events.dat',
Guide won't know about them.

Essentially, all Guide does is to look for .etb files in the Guide
directory, and combine them with any listed in 'events.dat'. You
may still have (for example) "worldocc.etb" out on the CD-ROM,
but once it's absent from "events.dat", Guide will ignore it.

Truman, I don't have actual answers to either problem. I
would warn you that if you copy the old software over on top
of the updated one, all sorts of things will break. One example
of many: the updated software makes use of the full range of
32-bit colors, and writes out data in that format in Guide's
"startup.mar" file. Suppose you run that updated software,
and it creates this (and several other) files in newer formats.

Then you go back to the older software. It has absolutely
no idea how to deal with these revised formats, none of which
were more than a "gee, I ought to do that someday" back
when said older software was written. Crash, burn, ugly
things happen...

I doubt that it's possible to fix all the files that would be
corrupted by this. You will probably have to delete your
Guide folder and re-install.

This _may_ account for the problem with your lat/lon.
Another possibility that seems likely to me is that the file
'startup.mar' has been set to be read-only. This would keep
Guide from changing it so that _all_ values, such as mag
limits, observer location, colors, displayed items, etc.,
would be fixed; any changes you made while running Guide
would fail to be stored to disk when you were done.

Depending on when you did it, though, it could mean that
'startup.mar' is still in the older format. That might explain
why your older Guide is able to read it, instead of crashing
almost immediately after starting up.

David, about the suggestion that the A2.0 CD might not be
ready: Guide asks you for the disk(s) needed to cover the given
area, and waits for you to click "OK". If you do that before the
disk has "settled", or with the wrong disk in the drive, Guide
just asks you for the disk(s) again. Under no circumstances
should it go to an "open file" dialog. This is _very_ puzzling to me.

Dario, I'll have to dig into this a bit... it looks as if that NASA
site has been updated. It used to use DE-200, and I used the
data from it in Guide's "Extras... Solar Eclipses" function. (If
you click on that, and ask for data for the eclipse in question,
you will see that the time given is slightly different, and matches
that given by Guide.)

It is possible to use Guide with any of JPL's DE ephemerides,
including DE-406. I'll write up something about this and post it.

-- Bill