Comet C/2021 T4 (Lemmon)
Comet C/2021 T4 (Lemmon) is in the constellation of
Coma,
at a distance of
View interactive star map
Celestial Coordinates
Apparent
J2000
Additional Information
The observed values of Magnitude, Coma Diameter and Tail Length are derived from the most recent observation recorded at the Comet Observers Database. The value of Predicted Magnitude comes from the JPL Horizons ephemerides service and, in the case of comets, might be inaccurate given the highly dynamic and unpredictable behavior of these objects. When available, please refer to the Observed Magnitude value and consider the Predicted Magnitude as a directional indication. We acknowledge with thanks the comet observations from the COBS Comet Observation Database contributed by observers worldwide and used in this table to report recent comet observations.
Rise and Set Times
Today's rise, transit and set times of Comet C/2021 T4 (Lemmon) from Greenwich, UK (all times relative to the local timezone Europe/London):
- C/2021 T4 (Lemmon) is above the horizon from Greenwich, UK.
- Right now it is placed in the East-North-East direction at an altitude of 3.49° above the horizon.
- Given its current magnitude, C/2021 T4 (Lemmon) is visible only through long exposure photography.
- Go to interactive sky chart
If you need to access this information frequently for your observations, you can create a simple customized Quick Access page, so that you can easily bookmark it in your browser favorites or add a shortcut to your mobile phones' home screen.
Finder Charts
High precision deep sky finder chart, 60 arcmin wide, showing where Comet C/2021 T4 (Lemmon) is right now. Click on the image to see a more detailed fullscreen tracker view.
Also check out Where is Comet C/2021 T4 (Lemmon)?, a page that provides all the information needed to find Comet C/2021 T4 (Lemmon) in the sky and additional links to sky charts.
Distance from Earth
The distance of Comet C/2021 T4 (Lemmon) from Earth is currently
The following chart shows the distance of Comet C/2021 T4 (Lemmon) from Earth as a function of time. In the chart the distance data is measured in Astronomical Units and sampled with an interval of 1 day.
The value of the reported distance might be somewhat inaccurate around the times of closest approach for objects passing extremely close to Earth. The value of the distance of C/2021 T4 (Lemmon) from Earth is also available as a real time updated value in the Live Position and Data Tracker.
Closest Approach
Between 1 January 2000 and 31 December 2099, the closest approach of Comet C/2021 T4 (Lemmon) to Earth happens on Fri Jul 21 2023 at a distance of 0.541534 Astronomical Units, or 81,012,307 kilometers:
NOTE: values for the closest approach are computed with a sampling interval of 1 day.
Light Curve
The following chart is the predicted light curve (visual magnitude as a function of time) of Comet C/2021 T4 (Lemmon), according to the most recent ephemerides data. Magnitude data is sampled with a 2 days interval and there might be inaccuracies for objects changing brightness very rapidly during the course of a few days. For comets there could be large discrepancies between the observed and predicted brightness because of their highly dynamic behaviour.
Orbital Elements
The following table lists the orbital elements of Comet C/2021 T4 (Lemmon) at epoch 19 August 2022 00:00 UTC (JD: 2459811.5). Source: JPL Small-Body Database
| Element | Symbol | Value |
|---|---|---|
| Orbit eccentricity | e | 0.99996874 |
| Orbit inclination | i | 160.75778068° |
| Perihelion distance | q | 1.48199298 AU 221,702,995 km |
| Aphelion distance | Q |
94,810.21049579 AU 14,183,405,639,233 km |
| Semi-major axis | a |
47,405.84624439 AU 7,091,813,671,114 km |
| Orbital period | period |
10,321,814.6864 years 3,770,042,814.1990 days |
| Date of perihelion transit | Tp | 2023-Jul-31 12:33:47 2,460,157.0235 JD |
| Next perihelion transit | 2023-Jul-31 12:33 3,772,502,971.2225 JD |
|
| Argument of perihelion | peri | 329.7808734849° |
| Longitude of the ascending node | node | 257.8014092137° |
| Mean anomaly | M | 359.99996700609° |
| Mean motion | n | 0.00000010°/day |
Orbit Visualization
View Comet C/2021 T4 (Lemmon) in the 3D Solar System Simulator
15 Days Ephemeris
The following table lists the ephemerides of Comet C/2021 T4 (Lemmon) computed for the past and next 7 days, with a 24 hours interval. Apparent celestial coordinates are provided.
| Date | Right AscensionR.A. | DeclinationDec. | MagnitudeMag | Constellation |
|---|---|---|---|---|
| 2024 Sep 11 | 12h 03m 26s | +17° 02’ 14” | 18.52 | Coma |
| 2024 Sep 12 | 12h 03m 51s | +16° 59’ 45” | 18.53 | Coma |
| 2024 Sep 13 | 12h 04m 16s | +16° 57’ 18” | 18.54 | Coma |
| 2024 Sep 14 | 12h 04m 42s | +16° 54’ 54” | 18.55 | Coma |
| 2024 Sep 15 | 12h 05m 07s | +16° 52’ 32” | 18.56 | Coma |
| 2024 Sep 16 | 12h 05m 32s | +16° 50’ 14” | 18.57 | Coma |
| 2024 Sep 17 | 12h 05m 57s | +16° 47’ 57” | 18.58 | Coma |
| 2024 Sep 18 | 12h 06m 23s | +16° 45’ 44” | 18.59 | Coma |
| 2024 Sep 19 | 12h 06m 48s | +16° 43’ 33” | 18.60 | Coma |
| 2024 Sep 20 | 12h 07m 13s | +16° 41’ 25” | 18.61 | Coma |
| 2024 Sep 21 | 12h 07m 39s | +16° 39’ 20” | 18.61 | Coma |
| 2024 Sep 22 | 12h 08m 04s | +16° 37’ 18” | 18.62 | Coma |
| 2024 Sep 23 | 12h 08m 29s | +16° 35’ 19” | 18.63 | Coma |
| 2024 Sep 24 | 12h 08m 54s | +16° 33’ 22” | 18.64 | Coma |
Additional Resources
- Position and finder charts (see also Where is Comet C/2021 T4 (Lemmon)?)
- Distance from Earth (see also How far is Comet C/2021 T4 (Lemmon) from Earth?)
- When does Comet C/2021 T4 (Lemmon) rise and set?
- Brightness (see also How bright is Comet C/2021 T4 (Lemmon)?)
- Orbital elements. Detailed information about Comet C/2021 T4 (Lemmon) orbital parameters.
- Interactive orbit visualization. 3d visualization showing the orbit of Comet C/2021 T4 (Lemmon) with respect to the major Solar System objects.
- 15 days ephemerides. Table showing celestial coordinates and magnitude of Comet C/2021 T4 (Lemmon) for the past and next 7 days.
- Interactive sky chart. An online planetarium application that shows where to locate Comet C/2021 T4 (Lemmon) in the sky from your location.
- Live position tracker. A high precision sky chart that uses real deep sky imagery to help locate Comet C/2021 T4 (Lemmon) with your telescope or on your astrophotographies.