Re: [guide-user] Asteroids display dependent on azimuth

Gerhard Dangl Apr 15, 2017

Hi Bill,

many thanks for the very fast analysis, the explanation and fix of the
MP display problem.

It works perfect now.

Best regards
Gerhard Dangl

Am 15.04.2017 um 19:09 schrieb Bill Gray pluto@...
> Hi Gerhard,
> The screen shots did the trick. After setting the same lat/lon,
> time, etc., I got the same behavior. If I center on the RA/dec
> for the "mp_off" image, most of the minor planets are missing;
> move a little, and they go back on again. That allowed me to track
> down the bug. It would affect any wide fields near the ecliptic
> poles.
> Guide has some code that computes a rectangle, in ecliptic
> coordinates, that covers the on-screen rectangle. It can then very
> quickly recognize that most asteroids, at the currently-specified
> time, cannot possibly be in that range of ecliptic latitude or
> longitude.
> The code in question makes displaying asteroids a _lot_ faster.
> But for some wide fields near the ecliptic poles, it could decide
> that the range in ecliptic longitude was effectively zero. That
> made it run even faster (since it would mean there were almost
> no asteroids to display), but it wasn't really what you would
> want to have happen. Fortunately, changing one line of code
> caused it to work properly.
> To ge the fix, download one of the following files and unZIP
> it in your Guide folder :
> Use the first for Guide 9 or 9.1, or the second for Guide 8.0.
> Things are actually a little trickier for Guide 8.0 users (though
> not by a lot); they should take a look at the following :
> Essentially, this boils down to "don't apply a Guide 9 update
> unless you've applied the latest Guide 8.0 update."
> -- Bill