2003UB313 - "Eris"
or a Dwarf Planet by any other name..
Sample CCD images
Background
This page explains how to add the object
2003UB313 to TheSky. (I won't comment as to whether or not this object is
a
"planet" or a
"minor planet" or now officially a Dwarf Planet. That is up to the IAU.
The object the object "2003UB313" IS
available as a minor planet regardless of what it is called, therefore it can be imported into TheSky6
for plotting, searching, labeling, and watching its' motion over time using
TheSky's Minor Planet Importing.
The easiest way is to import "2003UB313" is
to use Data | Comets and Minor Planets | Minor Planets | By Name
command:
Import Minor Planet
By Name
After clicking the button "By
Name" highlighted above just type the name of the minor planet(s) you want to add.
Wait!
I don't see the option! You must have the latest
TheSky6 Hotfix
installed to see the feature.
WARNING! The entered name must be exact. Trying
to substring search or entering any name incorrectly will not return any minor planets.
Enter name(s) to search
Note the examples shown
UB313 Officially named "Eris"
Type in "Eris" here
Click the minor planet(s)
name you want!
Drag all of them
or select them individually
Once the object has been imported into
TheSky, you can find it using the Edit | Find command. Enter minor
planet designation 2003UB313
or the official name Eris.
Edit | Find
Enter name or find it
listed under Minor Planets
You can now center on the object. The
Object Information also shows current information.
Current information for August 16th 2006
Distance, magnitude, etc.
Because there are several sources that
offer an Ephemeris for the object this data can easily be plotted in
TheSky
to compare with TheSky's computed position for the object.
Ephemeris:
2003 UB313
a,e,i = 67.71, 0.44, 44
q = 37.808
Date TT R. A. (2000) Decl.
Delta r Elong.
Phase V
2005 07 29 01 39.38 -05 19.3
96.681 96.939 104.4 0.6
18.9
2005 08 08 01 39.30 -05 21.0
96.526 96.937 113.7 0.5
18.9
2005 08 18 01 39.16 -05 22.9
96.382 96.936 122.9 0.5
18.9
2005 08 28 01 38.97 -05 25.0
96.254 96.934 132.1 0.4
18.8
2005 09 07 01 38.72 -05 27.3
96.146 96.933 141.2 0.4
18.8
2005 09 17 01 38.42 -05 29.5
96.061 96.932 149.9 0.3
18.8
2005 09 27 01 38.10 -05 31.8
96.001 96.930 157.9 0.2
18.8
2005 10 07 01 37.74 -05 33.9
95.968 96.929 163.9 0.2
18.8
2005 10 17 01 37.37 -05 35.8
95.965 96.928 165.0 0.2
18.8
2005 10 27 01 37.00 -05 37.4
95.990 96.926 160.3 0.2
18.8
2005 11 06 01 36.64 -05 38.7
96.043 96.925 152.7 0.3
18.8
2005 11 16 01 36.30 -05 39.6
96.124 96.924 143.8 0.3
18.8
2005 11 26 01 35.99 -05 40.1
96.229 96.922 134.4 0.4
18.8
2005 12 06 01 35.72 -05 40.1
96.355 96.921 124.8 0.5
18.8
2005 12 16 01 35.50 -05 39.6
96.499 96.919 115.0 0.5
18.9
2005 12 26 01 35.34 -05 38.7
96.656 96.918 105.2 0.6
18.9
2006 01 05 01 35.25 -05 37.3
96.821 96.917 95.3 0.6
18.9
2006 01 15 01 35.22 -05 35.4
96.988 96.915 85.4 0.6
18.9
2006 01 25 01 35.26 -05 33.2
97.154 96.914 75.6 0.6
18.9
2006 02 04 01 35.36 -05 30.7
97.311 96.913 65.9 0.5
18.9
2006 02 14 01 35.53 -05 27.9
97.457 96.911 56.2 0.5
18.9
2006 02 24 01 35.75 -05 25.0
97.586 96.910 46.7 0.4
18.9
2006 03 06 01 36.03 -05 21.9
97.694 96.908 37.5 0.4
18.9
If we add the following header definition
needed to define the fields of information the above Ephemeris can easily be
compiled into and SDB and plotted in
TheSky for a direct comparison to
TheSky's computed position.
>SEARCH 1,10
>RAHOURS 15,16
>RAMINUTES 18,22
>DECSIGN 26,26
>DECDEGREES 27,28
>DECMINUTES 30,33
>MAGNITUDE 71,75
>PARSE "Date/Time" 1,10
>PARSE "Delta" 36,42
>PARSE "r" 45,51
>PARSE "Elong" 54,59
>PARSE "Phase" 63,67
>PARSE "V" 71,75
>IDENTIFIER Ephemeris 2003 UB313
>LOADMEMORY
>OBJECT TYPE 55
;NOTE The first two lines are commented out
with ; - semi colons
;Ephemeris:
;2003 UB313
a,e,i = 67.71, 0.44, 44
q = 37.808
Date TT R. A. (2000) Decl.
Delta r Elong.
Phase V
2005 07 29 01 39.38 -05 19.3
96.681 96.939 104.4 0.6
18.9
2005 08 08 01 39.30 -05 21.0
96.526 96.937 113.7 0.5
18.9
2005 08 18 01 39.16 -05 22.9
96.382 96.936 122.9 0.5
18.9
2005 08 28 01 38.97 -05 25.0
96.254 96.934 132.1 0.4
18.8
2005 09 07 01 38.72 -05 27.3
96.146 96.933 141.2 0.4
18.8
2005 09 17 01 38.42 -05 29.5
96.061 96.932 149.9 0.3
18.8
2005 09 27 01 38.10 -05 31.8
96.001 96.930 157.9 0.2
18.8
2005 10 07 01 37.74 -05 33.9
95.968 96.929 163.9 0.2
18.8
2005 10 17 01 37.37 -05 35.8
95.965 96.928 165.0 0.2
18.8
2005 10 27 01 37.00 -05 37.4
95.990 96.926 160.3 0.2
18.8
2005 11 06 01 36.64 -05 38.7
96.043 96.925 152.7 0.3
18.8
2005 11 16 01 36.30 -05 39.6
96.124 96.924 143.8 0.3
18.8
2005 11 26 01 35.99 -05 40.1
96.229 96.922 134.4 0.4
18.8
2005 12 06 01 35.72 -05 40.1
96.355 96.921 124.8 0.5
18.8
2005 12 16 01 35.50 -05 39.6
96.499 96.919 115.0 0.5
18.9
2005 12 26 01 35.34 -05 38.7
96.656 96.918 105.2 0.6
18.9
2006 01 05 01 35.25 -05 37.3
96.821 96.917 95.3 0.6
18.9
2006 01 15 01 35.22 -05 35.4
96.988 96.915 85.4 0.6
18.9
2006 01 25 01 35.26 -05 33.2
97.154 96.914 75.6 0.6
18.9
2006 02 04 01 35.36 -05 30.7
97.311 96.913 65.9 0.5
18.9
2006 02 14 01 35.53 -05 27.9
97.457 96.911 56.2 0.5
18.9
2006 02 24 01 35.75 -05 25.0
97.586 96.910 46.7 0.4
18.9
2006 03 06 01 36.03 -05 21.9
97.694 96.908 37.5 0.4
18.9
Save the new text file with both
the Ephemeris and header to a text file.
Next compile the text file into an SDB using Data | Import. <--
Click here to read exactly how that is done!
Sample screen shot showing predicted path in
TheSky versus Ephemeris.
Predicted path versus
Ephemeris above shown here
Cool!
Object Paths for 2003 UB313
Connected lines and labels
The minor planet positions of
objects with a stable orbit are
very accurate (on the order of an arcsecond or better when current refined
orbital elements are supplied).
NOTE: There is a small discrepancy when
comparing the Ephemeris data to the computed position, on the order of 8
arcseconds. I attribute that to either better orbital elements that have
been refined over time versus the older data found in the Ephemeris.
The default scaling of the 3D
Solar System mode is based Pluto's orbit, so 2003UB313's orbit simply will not show
immediately.
Use TheSky's Lock On feature from
the Object Information's Utility tab, you can take a ride on the object!
Lock On
the object
Then time skip say 60 days (60d)
60 day time skip
and take a ride!
Now you can watch the object
approach the solar system and cross Pluto's orbit!
Takes a looong time (in years)!
This puts things into perspective!
Early image of the object
taken remotely over the web - Las Campanas, Chile
Date July 30, 2005 5:00 UT from Italy
Click here for details on the completely remote
imaging site.
CCD Image Courtesy Gianluca Masi
C-14/Paramount
GT-1100S/Apogee CCD camera
2003 - UB313
C-14/Paramount
ME/ST-10XE
- 2 minute exposure
holes in stars are matching stars from TheSky's data
North is down in the above
image as indicated by the reported North angle 179.50 degrees. The Paramount
ME being a German EQ mount will flip north angle depending on what side of
the meridian the mount is on.
After performing the
one-click astrometry using
TheSky/CCDSoft we get the following position formatted for the Minor Planet
Center. Using 24 stars from the UCAC2 data and a residual filter of 0.5 we
get an RMS solution of 0.25 arcseconds or one quarter of an arcsecond
accuracy.
2003UB313 C2006 08
29.43683 01 39 26.36 -05 09 53.7 19.0 XXX
TheSky's coordinates
Equatorial 2000: RA: 01h 39m 26s Dec: -05°09'54" versus the astrometric
position: RA 2000 01h 39d 26.36s -05d 09m 53.7s. Only a few arcseconds
difference.
Equatorial: RA: 01h 39m 47s Dec: -05°07'39"(current)
<--refined for current date!
NOTE: TheSky reports
both Epoch 2000 coordinates and the currently refined local date/time
coordinates. They differ slightly! You must compare apples to apples or
Epoch 2000 to Epoch 2000. The current epoch coordinates are more accurate
but the convention for the MPC is to use Epoch 2000. Here you will see only
a small discrepancy in the computed position and the astrometric position.
But Wait!
Why aren't the positions
identical? Which one is more accurate?
Because the astrometric
solution is using the stars in the field to precisely compute an astrometric
solution to better than 1/2 an arcsecond this position is more accurate then
the computed position of the object by using the orbital elements supplied
to TheSky. This kind of astrometric accuracy allows the refining of the
orbital elements. Small differences in position are not unexpected
especially with newer objects or those with un-stable orbits. ALWAYS supply
the most recent set of orbital elements you can!
Why is the magnitude so far
off?
Actually at a difference of
~1/10th of a magnitude error this is reasonably accurate considering the
image was not calibrated (i.e. no flat field). And keep in mind that the
Minor Planet Center is more concerned with the positional accuracy (1/2 an
arcsecond or better) NOT the photometry.
TheSky's computed
information
Object name: 2003 UB313
Magnitude: 18.7
Equatorial: RA: 01h 39m 47s Dec: -05°07'39"(current)
Equatorial 2000: RA: 01h 39m 26s Dec: -05°09'54"
Horizon: Azim: 176°11'27" Alt: +44°09'43"
Visibility: Rise 04:55, Set 16:23
Transit time: 10:39
Object type: Minor planet
Sun distance (au): 96.86
Hour angle: -00h 10m 58s
Air mass: 1.44
Screen x,y: 1026.00, 580.00
RA rate (arcsecs/sec): -0.0002
Dec rate (arcsecs/sec): -0.0002
Minor planet epoch month: 8.0000
Minor planet epoch day: 29.0000
Minor planet epoch year: 2006.0000
Minor planet mean anomaly: 197.7624
Minor planet eccentricity: 0.4410
Minor planet semi-major axis: 67.6941
Minor planet inclination: 44.1793
Heliocentric: l: 00°21'37"b: 00°15'00"r: 96.8573
Heliocentric longitude: 00°21'37"
Heliocentric latitude: 00°15'00"
Sidereal time: 01:29
Image Link information - True
center of field
Object name: Image Link Information
Equatorial: RA: 01h 39m 39s Dec: -05°08'32"(current)
Equatorial 2000: RA: 01h 39m 18s Dec: -05°10'46"
Horizon: Azim: 257°58'59" Alt: +06°14'23"
Visibility: Rise 22:22, Set 09:55
Transit time: 04:11
Position angle: 179°23'
Hour angle: 05h 09m 55s
Air mass: 8.60
Screen x,y: 615.00, 454.00
Sidereal time: 06:50
Click distance: 500.0000
Scale: 2.1577
Height: 17.6058
Width: 26.1806 |
