Skip to content
Public Universe
Asteroid Near-Earth

2021 SG1

Add to an observing list or journal →

(2021 SG1)

Where is it now

Distance from Sun
1.12 AU
True anomaly
209.44°
Distance from Earth
1.158 AU
As of
22 October 2026

Two-body Kepler propagation — accurate to ~0.1% for major planets over decades, less so for highly-perturbed bodies. Use JPL Horizons for high precision.

Sun Earth — 0.995 AU from the Sun Earth 2021 SG1 — 1.12 AU from the Sun 2021 SG1
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2021 SG1 is 1.158 AU from Earth today (9.6 light-minutes).

In the sky

Right ascension
09h 49m 20s
Declination
+03° 20′ 40″
Constellation
Sextans
Distance from Earth
1.15 AU
Elongation from the Sun
62.2° — well clear of the Sun

Visible from both hemispheres.

From your location

See how high it is right now, whether it is up after civil twilight, and when it rises and sets where you are.

How do I find my coordinates?

Google Maps on a computer

  1. Right-click the spot where you'll be observing.
  2. The first line of the menu is the coordinates, e.g. 51.50722, -0.12758 — click it and they're copied.
  3. Paste them above.

Google Maps on a phone

  1. Press and hold the spot to drop a pin.
  2. The coordinates appear in the search bar (or on the pin's card) — tap to copy, then paste above.

A full Google Maps link works too, but the short maps.app.goo.gl share links don't carry coordinates — copy the numbers instead. We round to about a kilometre; that's all the sky calculation needs.

Know your what3words address? Paste it, e.g. ///filled.count.soap. This is optional — the three words are sent to what3words to convert them, and we don't store the address or the result.

Your location stays in your browser and is sent only for this calculation. Using a what3words address is optional; if you do, the three words go to what3words to be converted and we don't record them. Set a location first, then you can save an email alert for this object. See our privacy policy.

Two-body approximation, good to about a degree for the planets — enough to find the constellation and know whether it is up.

Orbital elements

Semi-major axis
0.964 AU
Eccentricity
0.199
Inclination
9.6°
Orbital period
345.8 days
Perihelion
0.772 AU
Aphelion
1.156 AU
Longitude of ascending node
180.15°
Argument of periapsis
65.43°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 1.3 LD
0.0034 AU
Tisserand (Jupiter)
6.229

Orbit quality

Orbit poorly determined (uncertainty code 7).

Observations used
20
Data arc
5 days
First observed
26 September 2021
Last observed
1 October 2021
Residual RMS
0.48 ″
Solution · Otto Matic
1 October 2021

Visual & observation

Absolute magnitude (H)
25.56

Discovery & classification

Aten Near-Earth Object

Close approaches 61 on record

Flyby geometry
Ecliptic flyby of 2021 SG1 at 2038-09-30 05:43 UTC Top-down view of the ecliptic, Earth at the centre, for the 2038-09-30 05:43 UTC close approach of 2021 SG1. Catalogue miss distance 99.1 LD · 3.81 × 10⁷ km. The curve is the geocentric path from 2038-09-27 to 2038-10-03, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 99.1 LD · 3.81 × 10⁷ km 2038-09-30 05:43 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2038-09-30 05:43 UTC close approach of 2021 SG1. Catalogue miss distance 99.1 LD · 3.81 × 10⁷ km. The curve is the geocentric path from 2038-09-27 to 2038-10-03, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate.

JPL Horizons

When (UTC) Body Distance Lunar distances Relative speed
2027-02-14 21:18:00 Venus 0.1061 AU 41.3 LD 9 km/s
2038-09-30 05:43:00 Earth 0.2546 AU 99.1 LD 14.8 km/s
2039-06-05 21:52:00 Venus 0.1012 AU 39.4 LD 8.8 km/s
2039-09-23 19:35:00 Earth 0.0725 AU 28.2 LD 6.4 km/s
2042-02-12 20:20:00 Earth 0.1409 AU 54.8 LD 10.6 km/s
2043-01-25 23:00:00 Earth 0.4507 AU 175.4 LD 20.4 km/s
2055-10-05 07:56:00 Earth 0.3743 AU 145.7 LD 18.3 km/s
2056-09-22 23:01:00 Earth 0.0422 AU 16.4 LD 8.9 km/s
2057-07-13 07:15:00 Earth 0.2568 AU 99.9 LD 6.2 km/s
2057-11-10 03:48:00 Earth 0.2222 AU 86.5 LD 5.9 km/s

Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.

Sources