Re: [guide-user] Comet Panstarrs (C/2013 X1)

Bill Gray Dec 6, 2015

Hi Tom,

I think I know what's going on here...

Guide displays asteroids first from the MPC's "soft02cm.txt" file,
on the theory that that file tends to stay up to date. Then it looks
through the IMCCE's "eltdat.txt" file, and finally the built-in
"cometg.txt" file.

When you're zoomed in, and comets are displayed to magnitude 13.3
or fainter, Guide finds C/2013 X1 in the first file and displays it,
and marks that fact so it doesn't get displayed twice.

When you are _not_ zoomed in, Guide finds C/2013 X1 in the first
file and decides it's too faint to be displayed. Then it finds the same
comet, but with brighter magnitude parameters, in the IMCCE file. And
this time, it's bright enough to show up.

There really should be a decent way around this. (The same bug could
cause other weird effects. If the IMCCE elements disagree with the MPC
ones, which is apt to happen in some cases, you might find that not only
do comet magnitudes vary depending on where you are, but so do comet
positions.) I may just have to keep track of _all_ comets from the MPC
file, displayed or not, and suppress _all_ of them from being shown
from the IMCCE and 'cometsg.txt' files.

Bottom line for this case, though, is that MPC is probably right,
and the comet isn't as bright as IMCCE thought it was.

-- Bill

On 12/05/2015 10:42 PM, 'Tom Kunsitis' kunsitis@... [guide-user] wrote:
> I noticed a strange phenomenon regarding Comet Panstarrs (C/2013 X1) in Guide 9.0. When I right click and ask for more information, it will give the estimated magnitude as 10.1 for zoom levels 4 and 5 and then show it as 13.3 for levels 6 and higher. The go to comets function always shows it as magnitude 13.3. I have data shown for comets set to auto at magnitude 11 for level 4 and magnitude 12.3 for level 5 so Panstarrs should not be showing at these levels. I am running the 27 July 2015 version of Guide 9.0. Has anyone else had this happen?
> ---------------------------------------------------------
> Tom Kunsitis - Richmond, Virginia USA