38P/Stephan-Oterma |
ephemeris |
date |
magn |
radius |
delta |
ra |
dec |
elong |
phase |
PA |
Perihelion | 13 Nov 2018 | 6.8 | 1.580 AU | 0.820 AU | 07h25m | +21°43' | 121.4° | 32.3° | 278° |
Nearest approach | 15 Dec 2018 | 6.9 | 1.631 AU | 0.731 AU | 08h11m | +34°49' | 143.4° | 21.1° | 263° |
Today | 2 Jul 2025 | 41.8 | 14.508 AU | 13.795 AU | 15h32m | -11°38' | 133.0° | 2.9° | 111° |
38P/Stephan-Oterma- 2025-07-02
astro.vanbuitenen.nl
The interactive orbit chart above shows the comet's path through the solar system and its position at the given date.
Green and blue lines are shown perpendicular to the ecliptic plane: Green if the path is above the ecliptic plane, blue if it is below.
(Left-click and drag to rotate the view; Right-click and drag to move the view; Use scroll wheel to zoom in our out.)
The orbital elements of 38P/Stephan-Oterma are:
e (Eccentricity) : 0.8597710
q (Perihelion distance) : 1.5796780
i (Inclination) : 18.41420
Ω (Longitude of ascending node) : 77.86120
ω (Argument of perihelion) : 359.59290
L (Longitude of perihelion) : 77.47494
B (Latitude of perihelion) : -0.12860
T (Time of perihelion passage) : 2458436.36970
P (Orbital period in years) : 37.81
Epoch : 2025 Jun 30
Reference : MPEC 2024-YC7
Classification(s): : Nearly isotropic; Returning (a < 10000 AU); Halley type (P < 200 years)
The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC.
The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (3.50 + 5 log[∆] + 30.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 1.26 + 5 log[∆] + 30.00 log[r]).
The all-sky chart below shows the path of the comet over the same period as the light curve. The comet's current position is marked yellow.
The following chart shows the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.
A more printer-friendly version of the same chart can be found further down this page as well.
The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.
A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.
Ephemerides:
Date Time RA (2000) DEC (2000) delta radius elong phase PA magn
2025-07-02 00:00 UT 15 32 18.5 -11 38 28 13.793 14.507 133.1 2.9 111 41.8
2025-07-02 02:51 UT 15 32 17.3 -11 38 27 13.795 14.508 133.0 2.9 111 41.8
2025-07-03 00:00 UT 15 32 08.7 -11 38 25 13.808 14.511 132.2 3.0 111 41.8
2025-07-04 00:00 UT 15 31 59.0 -11 38 23 13.824 14.514 131.2 3.0 110 41.8
2025-07-05 00:00 UT 15 31 49.6 -11 38 23 13.840 14.517 130.2 3.1 110 41.8
2025-07-06 00:00 UT 15 31 40.4 -11 38 24 13.856 14.520 129.2 3.1 110 41.8
2025-07-07 00:00 UT 15 31 31.5 -11 38 25 13.872 14.524 128.3 3.2 110 41.8
2025-07-08 00:00 UT 15 31 22.8 -11 38 28 13.888 14.527 127.3 3.2 110 41.8
2025-07-09 00:00 UT 15 31 14.3 -11 38 32 13.904 14.530 126.3 3.2 109 41.8
2025-07-10 00:00 UT 15 31 06.0 -11 38 37 13.921 14.533 125.3 3.3 109 41.8
2025-07-11 00:00 UT 15 30 58.0 -11 38 43 13.938 14.536 124.4 3.3 109 41.9
2025-07-12 00:00 UT 15 30 50.3 -11 38 51 13.955 14.540 123.4 3.3 109 41.9
Terminology:
delta: distance between comet and earth in AU
radius: distance between comet and sun in AU
magn: magnitude (brightness) estimate
ra: right ascension in hours (24h = 360deg)
dec: declination in degrees
elong: elongation in degrees (angle sun-earth-comet)
phase: phase angle in degrees (angle sun-comet-earth)
AU: Astronomical Unit (mean distance between earth and sun: 149597870.7 km
Orbital elements usually provided by the MPC (Minor Planet Center).
Observations contributed by observers worldwide, via COBS (Comet Observation Database) or the MPC (Minor Planet Center)
Calculations by a modified version of AAPlus, a C# implementation of the AA+ project by PJ Naughter from the algorithms presented in the book "Astronomical Algorithms" by Jean Meeus.
NGC2000 dso catalog and star labels from VizieR as provided by the Strasbourg astronomical Data Center.
Tycho2 catalog from the ESO archive.