Of many, many things...

Bill J Gray Jun 20, 2003

Hi folks,

A lot of territory to cover... Robert Orso's handy new program
for getting planet bitmaps into Guide; a new "test update" to
Guide that addresses various problems mentioned on this list;
position angle conventions; the Micro-Guider I; and Titan
dropping off printouts. In order:

QWE CONVERSION:

Robert, many thanks for the QWE converter! I've long thought
I ought to provide such a program, and am glad to see it finally
in operation.

I'll be compiling a list of links to images suitable for
conversion. Just for starters, some good images can be found at:

http://maps.jpl.nasa.gov/
http://www.mmedia.is/~bjj/
http://gw.marketingden.com/planets/planets.html

That last includes an image for the Sun, so you can get something
a little more realistic than the "black triangles on a yellow disk"
that is the norm for our nearest star.

I hope also to provide a QWE with an ALPO Mars map for the 1956
opposition, complete with intricate web of "canals". (This can be
seen in "miniature" form on page 32 of the June 2003 _Sky & Telescope_,
in full form on pages 502 and 503 of the September 1956 issue, and
also appeared in the _Strolling Astronomer_.) Sort of a follow-up
to the Schiaparelli map I posted a while back.

TEST UPDATE POSTED:

I've just posted a "test update" at

http://www.projectpluto.com/new.htm

which includes such things as the +/-12:00 hour angle (as well as
a way to get the original 0-24h behavior), the "second time", the
"sec(z)", the "user-adjusted horizon altitude", plus fixes to
assorted bugs reported both on and off-list.

REVERSE POSITION ANGLE:

Paul, can't say I've ever heard of position angle being measured
"backwards" like that... azimuth is sometimes reckoned clockwise from
the south instead of clockwise from the north, but I know of only
one convention in use for PA. Perhaps the artificial satellite folk
have an alternative convention?

MICRO-GUIDER I:

Ray, if the MG-I is responding to the 'Q' command, then it's
probably Tangent-compatible and Guide ought to be able to use it
(after you've gone through the initialization routine, aligning
on two stars). This assumes it replies to the 'Q' command in the
Tangent-compatible manner described at

http://www.projectpluto.com/encoders.htm#communication

Only the 'Q' command is absolutely essential. If the device
balks at attempts to use the 'R' resolution-setting command, then
you will get an error message such as

Sent 'R08192,08192' for resolution; got back '-1'

when Guide attempts to first communicate with the scope. But
the error message can be ignored in such cases... and I see that
the Celestron Advanced Astro-Master is one of these, so perhaps
the MG-I also has no "set resolution" command, and therefore falls
into the same trap. See

http://www.projectpluto.com/encoders.htm#aam

for further comments on this.

Aside from that, yes, Guide will do the functions you mention.

TITAN ABSENCE ON PRINTOUTS:

Julian, Guide probably _is_ showing Titan... but at level 11, it's
too small to show a disk (and becomes just a labelled symbol). At
level 12, it's becoming a disk (albeit a tiny one, possibly too small
to be obvious on the printout.)

On a printout, you've got higher resolution than on-screen, and
Guide adjusts the disk/symbol boundary accordingly. Thus, Titan
appears as a disk on the printout, but doesn't change to a disk on-screen
until you zoom in another level or so.

To adjust that disk/symbol limit, hit Alt-J and enter

MIN_PLANET_SIZE=5

The default is 2. Experiment a bit, and you'll find a limit with
which you're comfortable (i.e., when a planet/satellite becomes a disk,
it's more blatantly visible.)

-- Bill