Where is Frank? the moon "Anthe", not the Gregorio

[Chuft-Captain]

After installing the latest version of Grant Hutchison's numberedmoons.ssc (http://shatters.net/forum/viewtopic.php?t=4369&highlight=ephemerides),
I noticed a couple of things...

Firstly, where is Frank?

According to this article :

...The moon's location in the Saturnian sky is between the orbits of Methone and Pallene.

but this is all I see:


Secondly, according to that same article Saturn currently has 60 moons, but I'm seeing 62 in the Solar System Browser.
Have another couple of moons been discovered since Jul. 19, 2007?

Could the 2 extras be 2007S2 and 2007S3???

[John Van Vliet]

hi you do realize that that was posted in 04

' Posted: Tue Feb 10, 2004 6:32 am"

[Derek]

Hi,

There is no Frank but rather Anthe (S2007 S4) and Grant's numberedmoons has in fact missed this one somehow otherwise it is up to date.
And yes there are in fact 63 saturn moons according to the following website:
http://www.dtm.ciw.edu/sheppard/satelli ... tdata.html

[Chuft-Captain]

hi you do realize that that was posted in 04

' Posted: Tue Feb 10, 2004 6:32 am"

Thanks for spotting that John, however I downloaded Revision1.35 (which is about 3 weeks old) from here: http://celestia.cvs.sourceforge.net/cel ... c?view=log

Hi,

There is no Frank but rather Anthe (S2007 S4) and Grant's numberedmoons has in fact missed this one somehow otherwise it is up to date.
And yes there are in fact 63 saturn moons according to the following website:
http://www.dtm.ciw.edu/sheppard/satelli ... tdata.html

Thanks Derek,
Frank was a temporary name assigned when it was first discovered, until a more suitable name was decided on. "Anthe" must be the name they finally settled on.

[Derek]

Hi,

Whoops can't count 60 moons rest of the info is correct

[Chuft-Captain]

WIKIhas 60 moons + 3 "uncertain objects around the F-Ring". (2004S3, 2004S4, 2004S6).

I note that Grant's SSC includes these 3 as well, so with the addition of Anthe, this would make the total 63.

[granthutchison]

Anthe is missing because I've yet to see a full orbital spec for it.
If you want to see it, download poormoons.ssc, hosted by Selden. Moons make the transition from poormoons.ssc to the distribution files when I get a good orbit for them.
Get the file here:
http://www.lepp.cornell.edu/~seb/celestia/hutchison/poormoons.html
or use this code:

Code: Select all

"Anthe" "Sol/Saturn" # IAUC 8857
{
   Texture       "asteroid.jpg"
   Mesh      "asteroid.cms"
   Radius      1

   EllipticalOrbit
   {
   Period      1.03650
   SemiMajorAxis   197700
   Eccentricity   0.001
   Inclination   0.1
   }

   Albedo 0.06 # Estimate
}

Grant

[Chuft-Captain]

Thanks Grant,

Looks good. .. I assume that this orbit is not very accurate because it's based on only a very few observations, and that's the reason you didn't include it.

I am guessing that once there are a few more observations, then HORIZONS will publish an accurate orbit at which time you'll stick an updated orbit into numberedmoons.ssc.

Is that the procedure??

Cheers
CC

[granthutchison]

Looks good. .. I assume that this orbit is not very accurate because it's based on only a very few observations, and that's the reason you didn't include it.

I like to have a mean anomaly or a mean longitude, so that the moon is positioned approximately correctly in its orbit: when I get a value for that, I "promote" the moon out of poormoons.ssc.
I've been considering moving 2004S3, 2004S4 and 2004S6 the other way, since they're looking likely to be temporary clumps in the ring material, but I'm hoping for some definitive information before I delete or demote them.

Grant

[ajtribick]

I'm wondering how an object which apparently doesn't have a well-characterised orbit has ended up getting a name... seems rather ridiculous to me.

[granthutchison]

I'm wondering how an object which apparently doesn't have a well-characterised orbit has ended up getting a name... seems rather ridiculous to me.

Given that it has been named, I'm sure it has a well-characterized orbit somewhere: just not published by the IAU or JPL so far.
In the past, I've been able to dig orbital elements out of the associated peer-reviewed publications, but I've come up empty with Anthe so far.

Grant

[BobHegwood]

Grant,

This is a related question. Given that releases of Celestia obviously
do NOT include all known moons and other planetary objects, do you
have a recommendation as to where most of the known moons can be
accessed in a format familiar to Celestia?

I know it's a dumb question, but I saw on the Science Channel the
other day that Saturn's known moons number at least 63 now, and
the actual moons of Jupiter are estimated at something approaching
200.

Would be nice to be able to add some of these things.

Thanks, Brain-Dead

[selden]

Bob,

In general, JPL's Horizons ephemeris service gives results which are easily transcribed into Celestia's SSC format. http://ssd.jpl.nasa.gov/?horizons

But what gave you the impression that there are a significant number of known moons omitted from Celestia?

All 60 of Saturn's moons for which orbital elements are known are included, for example. (See eariler in this thread.) Most of the orbital elements of the other 3 are simply not known, and Grant is unwilling to put those 3 in the official distribution until the information is available so Celestia can draw them in a reasonably accurate orbit. If you really want them anyhow, you can download his poormoons addon as described earlier in this thread.

[granthutchison]

Bob:
You'll have all the designated moons if you combine the Celestia distribution files (including numberedmoons.ssc) with the poormoons.ssc file I linked to above.
Definitive updates with good orbits go into numberedmoons.ssc. New discoveries with poorly defined orbits go into poormoons.ssc, and graduate to numberedmoons.ssc as good data come in. Poormoons.ssc always contains a header referencing the oldest compatible version of numberedmoons.ssc, like this:

Code: Select all

# Confirmed moons with poor orbital data.
# Only approximate data are used - positions in orbit as seen in
# Celestia are therefore *incorrect*, even for epoch.

# This file is maintained in tandem with "numberedmoons.ssc", available
# on the CVS tree at:
# http://celestia.cvs.sourceforge.net/celestia/celestia/extras/numberedmoons.ssc
# To avoid overlaps and drop-outs, you should use the current version of
# both files: this version of "poormoons.ssc" is not compatible with versions
# of "numberedmoons.ssc" prior to CVS version 1.26 (2006 October 19).

Grant

[BobHegwood]

Bob:
You'll have all the designated moons if you combine the Celestia distribution files (including numberedmoons.ssc) with the poormoons.ssc file I linked to above.
Definitive updates with good orbits go into numberedmoons.ssc. New discoveries with poorly defined orbits go into poormoons.ssc, and graduate to numberedmoons.ssc as good data come in. Poormoons.ssc always contains a header referencing the oldest compatible version of numberedmoons.ssc, like this

Okay, as always thanks for your help (and, of course, Selden's)

Unfortunately, my brain (never very good anyway) simply doesn't work
as well as it used to. There are a number of reasons for this, but this
is true now primarily because of my health.

Appreciate all the help, truly Brain-Dead Bob

[Chuft-Captain]

FYI,

I'm pretty sure that numberedmoons.ssc was NOT included in the 1.5.0 distribution. I had to get it separately from CVS.

CC

[Guckytos]

numberedmoons.ssc is definitly NOT included in the standard package of Celestia 1.5.0 (at least the windows version).