Slight chance to see Artemis II
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Gil Funk
Apr 3, 2026, 6:02:45 PM (4 days ago) Apr 3
to NOVAC, greenbe...@groups.io, capitalas...@groups.io, howar...@googlegroups.com
ALCON,
I’ve read on Cloudy Nights that someone has captured the Artemis II capsule on their Seestar S50, (20 sec exposure looks like a faint streak). The ephemerides are on JPL’s Horizon site.
If the clouds allow, there may be a chance to capture this yourself. I’m going to try tonight with my Dwarf III.
Here are the details from the JPL site.
Clear skies!
| Date (UT) | R.A. (ICRF) | DEC | APmag | S-brt | Delta | Deldot | S-O-T /r | S-T-O | Sky Motion | Sky Mot PA | RelVel-ANG | Lun Sky Brt | Sky SNR |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026-Apr-03 00:00 | 10 38 43.08 | -19 43 06.3 | n.a. | n.a. | 0.00002155626451 | 8.0781805 | 145.4522 /T | 34.5472 | 19753.912 | 71.994867 | 57.496474 | n.a. | n.a. |
| 2026-Apr-04 00:00 | 16 02 59.22 | -26 03 44.3 | n.a. | n.a. | 0.00140681539553 | 1.1637535 | 129.8151 /L | 50.1233 | 32.660711 | 109.70074 | 64.487580 | n.a. | n.a. |
| 2026-Apr-05 00:00 | 16 24 48.49 | -26 55 04.5 | n.a. | n.a. | 0.00206513802255 | 0.6741496 | 125.8519 /L | 54.0525 | 18.931037 | 109.50019 | 54.970675 | n.a. | n.a. |
*******************************************************************************
Revised: Apr 03, 2026 Artemis II / Spacecraft (Earth) -1024
18:09 UTC https://www.nasa.gov/mission/artemis-ii/
BACKGROUND:
Four astronauts will fly aboard NASA's Orion spacecraft to confirm the
spacecraft's systems operate as designed in preparation for a sustained
human presence on the Moon.
Artemis II astronauts are NASA's Reid Wiseman (Commander), Victor Glover
(pilot), Christina Koch (Mission Specialist), and CSA (Canadian Space
Agency) astronaut Jeremy Hansen (Mission Specialist).
"Artemis II" refers to a specific mission within the broader Artemis program.
"Orion" refers to the spacecraft/capsule the astronauts ride within. The
crew has chosen the nickname "Integrity" for the Artemis II Orion capsule.
"SLS" refers to the Space Launch System, or rocket launching Orion into space
MAJOR EVENTS:
Launched April 1 @ 22:35:12 UTC from pad LC-39B at the Kennedy Space
Center, USA. Mission length is 10 days.
MET column below gives timings of major dynamical events RELATIVE TO LAUNCH.
Format is "days/HH:MM:SS" since launch. Given launch time, MET converted to
absolute UTC date/time is also given, format "date HH:MM:{SS}". As the
mission develops, some times may differ somewhat from planning:
Day 1 MET Apr UTC
launch 0/00:00 1 22:35:12 - Launch April 1, 22:35:12 UTC
launch + 0/00:20 1 22:55 - Orion deploys solar arrays in Earth orbit
0/00:49:50 1 23:25:02 - Perigee raise maneuver (2223 x 185 km)
0/01:47:57 2 00:23:09 - Apogee raise maneuver (70377 km)
0/03:24:18 2 01:59:30 - Orion/ICPS separation
0/04:50 2 03:25 - Orion upper stage separation burn
0/05:00 2 03:35 - ICPS disposal burn for Pacific splashdown
0/05:04 2 03:39 - Cubesats deploy at one minute intervals
0/12:55 2 11:30 - Perigee raise burn
Day 2
launch + 1/01:14 2 23:49 - Start Translunar Injection burn (5m 55s)
1/01:19 2 23:54 - End TLI (delta-v= 388 m/s)
1/01:35 3 00:10 - Earth shadow entrance
1/02:41 3 01:17 - Earth shadow exit
Day 3
launch + 2/00:08 3 22:43 - Orbit trajectory correction burn #1
Day 4
launch + 3/01:08 4 23:43 - Orbit trajectory correction burn #2
Day 5
launch + 4/04:29 6 03:04 - Orbit trajectory correction burn #3
4/06:08 6 04:43 - Orion enters lunar sphere of influence
Day 6
launch + 5/00:31 6 23:06 - Closest approach to the Moon
5/00:34 6 23:09 - Maximum distance from Earth
Day 7
launch + 5/18:52 7 17:27 - Orion exits lunar sphere of influence
6/01:29 8 00:04 - Return trajectory correction burn #1
Day 8
launch + 7/04:20 9 02:55 - Manual piloting demonstration
Day 9
launch + 8/04:29 10 03:04 - Return trajectory correction burn #2
Day 10
launch + 8/20:29 10 19:04 - Return trajectory correction burn #3
9/01:09 10 23:44 - Orion crew and service module separation
9/01:12 10 23:47 - Crew module raise burn
9/01:29 11 00:04 - Entry interface (122 km above Earth)
Events by altitude:
11 km : Forward bay cover deploys
7.6 km: Droque parachute deploys
2.9 km: Pilot parachutes deploy @ 2.9 km,
pulling out 3 main parachutes
9/01:42 11 00:17 - Splashdown, Pacific Ocean, off Baja Cali.
9/01:57 11 00:32 - Orion final power down
SPACECRAFT DETAILS
SLS
* Height : 98 meters
* Mass at liftoff : 2.61 million kg
* Thrust at liftoff : 39.1 million Newtons
* Payload to the moon : 27,000 kg
Orion module ("Integrity")
* Crew + service mod hgt: 7.92 meters
* Pressurized volume : 19.6 m^3
* Mass to the Moon : ~27,000 kg
* Return mass at landing: ~10,400 kg (6500kg srvc mod, 1000kg adpt. discard)
* Propellant usage : ~ 9,000 kg
CUBESATS DISPENSED
All are 12U CubeSats from international partners tied to the Artemis Accords.
Independent missions and trajectories once released on Day 1.
1. ATENEA (Argentina space agency, CONAE)
Studies: Radiation environment, shielding techniques, communication
systems
Goal : Improve future deep-space mission design
2. TACHELES (Germany, German Aerospace Center (DLR))
Focus : Testing electronics and components
Goal : Validating tech for future lunar vehicles and infrastructure
3. K-RadCube (South Korea, Korea AeroSpace Administration (KASA))
Mission: Measure space radiation using materials that mimic human tissue
Goal : Study biological effects of radiation in space
4. Space Weather CubeSat-1 (Saudi Arabia, Saudi Space Agency)
Studies: Solar radiation, magnetic fields, space weather conditions
in high Earth orbit
SPACECRAFT TRAJECTORY:
Post-launch Orion II trajectory data from NASA/JSC navigation (concatenated):
Trajectory data starts after nominal ICPS separation, 3h24m18s after launch,
Trajectory name Start (TDB) Stop (TDB)
----------------------------------------- ----------------- -----------------
Orion_OEM_20260401_0335.V0.1 2026-Apr-02 01:59 2026-Apr-10 03:27
Orion_OEM_20260402_1414.V0.1 2026-Apr-02 03:27 2026-Apr-02 12:45
Orion_OEM_20260403_0318.V0.3 2026-Apr-02 12:45 2026-Apr-03 00:03
EPH_OEM_20260403_1626.V0.1 2026-Apr-03 00:03 2026-Apr-10 23:52
*******************************************************************************
*******************************************************************************
Ephemeris / WWW_USER Fri Apr 3 12:51:01 2026 Pasadena, USA / Horizons
*******************************************************************************
Target body name: Artemis II (spacecraft) (-1024) {source: Artemis_II_merged}
Center body name: Earth (399) {source: DE441}
Center-site name: (user defined site below)
*******************************************************************************
Start time : A.D. 2026-Apr-03 00:00:00.0000 UT
Stop time : A.D. 2026-Apr-05 00:00:00.0000 UT
Step-size : 1440 minutes
*******************************************************************************
Target pole/equ : undefined
Target radii : undefined
Center geodetic : 282.9, 39.08, 1.61706E-12 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 282.9, 4957.73334, 3999.21518 {E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : ITRF93 {East-longitude positive}
Center radii : 6378.137, 6378.137, 6356.752 km {Equator_a, b, pole_c}
Target primary : Earth
Vis. interferer : MOON (R_eq= 1737.400) km {source: DE441}
Rel. light bend : Sun {source: DE441}
Rel. lght bnd GM: 1.3271E+11 km^3/s^2
Atmos refraction: NO (AIRLESS)
RA format : HMS
Time format : CAL
Calendar mode : Mixed Julian/Gregorian
EOP file : eop.260402.p260629
EOP coverage : DATA-BASED 1962-JAN-20 TO 2026-APR-02. PREDICTS-> 2026-JUN-28
Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s
Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass (>38.000=NO), Daylight (NO )
Table cut-offs 2: Solar elongation ( 0.0,180.0=NO ),Local Hour Angle( 0.0=NO )
Table cut-offs 3: RA/DEC angular rate ( 0.0=NO )
******************************************************************************************************************************************************************************
Date__(UT)__HR:MN R.A._____(ICRF)_____DEC APmag S-brt delta deldot S-O-T /r S-T-O Sky_motion Sky_mot_PA RelVel-ANG Lun_Sky_Brt sky_SNR
******************************************************************************************************************************************************************************
$$SOE
2026-Apr-03 00:00 C 10 38 43.08 -19 43 06.3 n.a. n.a. 0.00002155626451 8.0781805 145.4522 /T 34.5472 19753.912 71.994867 57.496474 n.a. n.a.
2026-Apr-04 00:00 C 16 02 59.22 -26 03 44.3 n.a. n.a. 0.00140681539553 1.1637535 129.8151 /L 50.1233 32.660711 109.70074 64.487580 n.a. n.a.
2026-Apr-05 00:00 C 16 24 48.49 -26 55 04.5 n.a. n.a. 0.00206513802255 0.6741496 125.8519 /L 54.0525 18.931037 109.50019 54.970675 n.a. n.a.
$$EOE
******************************************************************************************************************************************************************************
Column meaning:
TIME
Times PRIOR to 1962 are UT1, a mean-solar time closely related to the
prior but now-deprecated GMT. Times AFTER 1962 are in UTC, the current
civil or "wall-clock" time-scale. UTC is kept within 0.9 seconds of UT1
using integer leap-seconds for 1972 and later years.
Conversion from the internal Barycentric Dynamical Time (TDB) of solar
system dynamics to the non-uniform civil UT time-scale requested for output
has not been determined for UTC times after the next July or January 1st.
Therefore, the last known leap-second is used as a constant over future
intervals.
Time tags refer to the UT time-scale conversion from TDB on Earth
regardless of observer location within the solar system, although clock
rates may differ due to the local gravity field and no analog to "UT"
may be defined for that location.
Any 'b' symbol in the 1st-column denotes a B.C. date. First-column blank
(" ") denotes an A.D. date.
CALENDAR SYSTEM
Mixed calendar mode was active such that calendar dates after AD 1582-Oct-15
(if any) are in the modern Gregorian system. Dates prior to 1582-Oct-5 (if any)
are in the Julian calendar system, which is automatically extended for dates
prior to its adoption on 45-Jan-1 BC. The Julian calendar is useful for
matching historical dates. The Gregorian calendar more accurately corresponds
to the Earth's orbital motion and seasons. A "Gregorian-only" calendar mode is
available if such physical events are the primary interest.
NOTE: "n.a." in output means quantity "not available" at the print-time.
SOLAR PRESENCE (OBSERVING SITE)
Time tag is followed by a blank, then a solar-presence symbol:
'*' Daylight (refracted solar upper-limb on or above apparent horizon)
'C' Civil twilight/dawn
'N' Nautical twilight/dawn
'A' Astronomical twilight/dawn
' ' Night OR geocentric ephemeris
LUNAR PRESENCE (OBSERVING SITE)
The solar-presence symbol is immediately followed by a lunar-presence symbol:
'm' Refracted upper-limb of Moon on or above apparent horizon
' ' Refracted upper-limb of Moon below apparent horizon OR geocentric
ephemeris
'R.A._____(ICRF)_____DEC' =
Astrometric right ascension and declination of the target center with
respect to the observing site (coordinate origin) in the reference frame of
the planetary ephemeris (ICRF). Compensated for down-leg light-time delay
aberration.
Units: RA in hours-minutes-seconds of time, HH MM SS.ff{ffff}
DEC in degrees-minutes-seconds of arc, sDD MN SC.f{ffff}
'APmag S-brt' =
The targets' approximate apparent visual magnitude and surface brightness.
For planets and natural satellites, output is restricted to solar phase angles
covered by observational data. Outside the observed phase angle range, "n.a."
may be output to avoid extrapolation beyond the limit of model validity.
For Earth-based observers, the estimated dimming due to atmospheric
absorption (extinction) is available as a separate, requestable quantity.
Surface brightness is the average airless visual magnitude of a
square-arcsecond of the illuminated portion of the apparent disk. It is
computed only if the target radius is known.
Units: MAGNITUDES & MAGNITUDES PER SQUARE ARCSECOND
'delta deldot' =
Apparent range ("delta", light-time aberrated) and range-rate ("delta-dot")
of the target center relative to the observer. A positive "deldot" means the
target center is moving away from the observer, negative indicates movement
toward the observer. Units: AU and KM/S
'S-O-T /r' =
Sun-Observer-Target apparent SOLAR ELONGATION ANGLE seen from the observers'
location at print-time.
The '/r' column provides a code indicating the targets' apparent position
relative to the Sun in the observers' sky, as described below:
Case A: For an observing location on the surface of a rotating body, that
body rotational sense is considered:
/T indicates target TRAILS Sun (evening sky: rises and sets AFTER Sun)
/L indicates target LEADS Sun (morning sky: rises and sets BEFORE Sun)
Case B: For an observing point that does not have a rotational model (such
as a spacecraft), the "leading" and "trailing" condition is defined by the
observers' heliocentric ORBITAL motion:
* If continuing in the observers' current direction of heliocentric
motion would encounter the targets' apparent longitude first, followed
by the Sun's, the target LEADS the Sun as seen by the observer.
* If the Sun's apparent longitude would be encountered first, followed
by the targets', the target TRAILS the Sun.
Two other codes can be output:
/* indicates observer is Sun-centered (undefined)
/? Target is aligned with Sun center (no lead or trail)
The S-O-T solar elongation angle is numerically the minimum separation
angle of the Sun and target in the sky in any direction. It does NOT indicate
the amount of separation in the leading or trailing directions, which would
be defined along the equator of a spherical coordinate system.
Units: DEGREES
'S-T-O' =
The Sun-Target-Observer angle; the interior vertex angle at target center
formed by a vector from the target to the apparent center of the Sun (at
reflection time on the target) and the apparent vector from target to the
observer at print-time. Slightly different from true PHASE ANGLE (requestable
separately) at the few arcsecond level in that it includes stellar aberration
on the down-leg from target to observer. Units: DEGREES
'Sky_motion Sky_mot_PA RelVel-ANG' =
Total apparent angular rate of the target in the plane-of-sky. "Sky_mot_PA"
is the position angle of the target's direction of motion in the plane-of-sky,
measured counter-clockwise from the apparent of-date north pole direction.
"RelVel-ANG" is the flight path angle of the target's relative motion with
respect to the observer's line-of-sight, in the range [-90,+90], where positive
values indicate motion away from the observer, negative values are toward the
observer:
-90 = target is moving directly toward the observer
0 = target is moving at right angles to the observer's line-of-sight
+90 = target is moving directly away from the observer
UNITS: ARCSECONDS/MINUTE, DEGREES, DEGREES
'Lun_Sky_Brt sky_SNR' =
Sky brightness due to moonlight scattered by Earth's atmosphere at the
target's position in the sky. "sky_SNR" is the visual signal-to-noise ratio
(SNR) of the target's surface brightness relative to background sky. Output
only for topocentric Earth observers when both the Moon and target are above
the local horizon and the Sun is in astronomical twilight (or further) below
the horizon, and the target is not the Moon or Sun. If all conditions are
not met, "n.a." is output. Galactic brightness, local sky light-pollution
and weather are NOT considered. Lunar opposition surge is considered. The
value returned is accurate under ideal conditions at the approximately 8-23%
level, so is a useful but not definitive value.
If the target-body radius is also known, "sky_SNR" is output. This is the
approximate visual signal-to-noise ratio of the target's brightness divided
by lunar sky brightness. When sky_SNR < 1, the target is dimmer than the
ideal moonlight-scattering background sky, so unlikely to be detectable at
visual wavelengths. In practice, visibility requires sky_SNR > 1 and a
detector sensitive enough to reach the target's magnitude, even if it isn't
washed out by moonlight. When relating magnitudes and brightness values,
keep in mind their logarithmic relationship m2-m1 = -2.5*log_10(b2/b1).
UNITS: VISUAL MAGNITUDES / ARCSECOND^2, and unitless ratio
Computations by ...
Solar System Dynamics Group, Horizons On-Line Ephemeris System
4800 Oak Grove Drive, Jet Propulsion Laboratory
Pasadena, CA 91109 USA
General site: https://ssd.jpl.nasa.gov/
Mailing list: https://ssd.jpl.nasa.gov/email_list.html
System news : https://ssd.jpl.nasa.gov/horizons/news.html
User Guide : https://ssd.jpl.nasa.gov/horizons/manual.html
Connect : browser https://ssd.jpl.nasa.gov/horizons/app.html#/x
command-line telnet ssd.jpl.nasa.gov 6775
e-mail/batch https://ssd.jpl.nasa.gov/ftp/ssd/horizons_batch.txt
Author : Jon.D.G...@jpl.nasa.gov
******************************************************************************************************************************************************************************
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