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🌎  Observing from: Greenwich, United Kingdom [change]
🌅 Sunrise: 6:38  ☀️ Transit: 13:03  🌅 Sunset: 19:28

Comet 77P/Longmore

Comet 77P/Longmore is currently in the constellation of Hydra. The current Right Ascension of Comet 77P/Longmore is 14h 25m 58s and the Declination is -25° 40’ 41” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom [change]). The current estimated magnitude of Comet 77P/Longmore is 15.61 (JPL) while the latest observed magnitude is 14.4 (COBS).

14h 25m 58s
-25° 40’ 41”

Today's rise, transit and set times of Comet 77P/Longmore from Greenwich, United Kingdom [change] (all times relative to the local timezone Europe/London):

Azimuth: 115.7°
Max altitude: 13.0°
Azimuth: 244.5°
  • 77P/Longmore is above the horizon from Greenwich, United Kingdom [change].
  • Right now it is placed in the South-East direction at an altitude of 2° above the horizon.
  • Given its current magnitude, 77P/Longmore is visible with the help of a telescope havng an aperture of 14 inches (350mm) or more.
  • 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.

Available Resources

Comet 77P/Longmore Position and Finder Charts

Below we provide Comet 77P/Longmore finder charts showing where the object is right now in the sky with respect to the brightest stars. The first finder chart has a field of view of 50 degrees, while the second one has a field of view of 10 degrees. Click on each finder chart to access a full screen interactive Online Planetarium.

Map showing Comet 77P/Longmore in Hydra on March, 31 2023
Field of view: 50x30 degrees
View fullscreen
Map showing Comet 77P/Longmore in Hydra on March, 31 2023
Field of view: 10x6 degrees
View fullscreen
 = visible to the naked eye
 = binocular, brighter than 10th magnitude
= current altitude ≥ 30°   = current altitude < 30°   = below the horizon
Location: Greenwich, United Kingdom [change]

Higher precision deep sky finder chart, 60 arcmin wide, showing where Comet 77P/Longmore is right now. Click on the image to see a more detailed fullscreen tracker view.

RA: 14h 25m 58s
Dec: -25° 40’ 41”
Deep sky finder chart for Comet 77P/Longmore
Field of view: 60x40 arcmins
View fullscreen

Also check out Where is Comet 77P/Longmore?, a page that provides all the information needed to find Comet 77P/Longmore in the sky and additional links to sky charts.

Comet 77P/Longmore Distance from Earth

The distance of Comet 77P/Longmore from Earth is currently 216,870,178 kilometers, equivalent to 1.449688 Astronomical Units. Light takes 12 minutes and 3.4010 seconds to travel from Comet 77P/Longmore and arrive to us.

12 minutes and 3.4010 seconds

The following chart shows the distance of Comet 77P/Longmore 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.

Chart of the distance of Comet 77P/Longmore from Earth in Astronomical Units (au)

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 77P/Longmore from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest Approach of Comet 77P/Longmore to Earth

Between 1 January 2013 and 30 December 2100, the closest approach of Comet 77P/Longmore to Earth happens on Sun Apr 22 2063 at a distance of 1.005949 Astronomical Units, or 150,487,808 kilometers:

Sun Apr 22 2063

NOTE: values for the closest approach are computed with a sampling interval of 1 day.

Comet 77P/Longmore Brightness

The current visual magnitude of Comet 77P/Longmore is 15.61.


The observed magnitude and coma diameter values are derived from the Comet Observers Database by averaging the values reported in recent observations (more recent than 4 days), when available. The Estimated Magnitude comes from the JPL Horizons ephemerides service and might be inaccurate given the highly dynamic and unpredictable behavior of comets. When available, please refer to the Observed Magnitude value and consider the Estimated 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.

The following chart is the predicted light curve (visual magnitude as a function of time) of Comet 77P/Longmore, 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.

Chart of the magnitude of Comet 77P/Longmore as a function of time

Comet 77P/Longmore Orbital Elements

The following table lists the orbital elements of Comet 77P/Longmore at epoch 19 May 2011 00:00 UTC (JD: 2455701.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.35722445
Orbit inclination i 24.39989618°
Perihelion distance q 2.31633337 AU
346,518,541 km
Aphelion distance Q 4.89095194 AU
731,675,997 km
Semi-major axis a 3.60364266 AU
539,097,269 km
Orbital period period 6.8410 years
2,498.6821 days
Date of perihelion transit Tp 2009-Jul-08 01:51:19
2,455,020.5773 JD
Next perihelion transit 2016-May-10 18:13
2,457,519.2594 JD
Argument of perihelion peri 196.95865461186°
Longitude of the ascending node node 14.909174866021°
Mean anomaly M 98.104583831402°
Mean motion n 0.14407595°/day

Visualization of Comet 77P/Longmore Orbit

This 3d orbit diagram is a feature of our 3D Solar System Simulator and shows the orbit of Comet 77P/Longmore with respect of the Sun and the orbits of the major planets. The position of Comet 77P/Longmore and the planets along their orbits in this diagram accurately represents the current configuration of the objects in the Solar System. This is an experimental feature and it requires a WebGL enabled browser. Please provide us feedback!

Orbit Diagram of Comet 77P/Longmore
View Comet 77P/Longmore in the 3D Solar System Simulator

Comet 77P/Longmore 15 Days Ephemeris

The following table lists the ephemerides of Comet 77P/Longmore computed for the past and next 7 days, with a 24 hours interval. Click on each row of the table to locate Comet 77P/Longmore in our Online Planetarium at the chosen date.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2023 Mar 24 14h 31m 22s -23° 59’ 38” 15.69 Libra
2023 Mar 25 14h 30m 48s -24° 12’ 38” 15.68 Libra
2023 Mar 26 14h 30m 12s -24° 25’ 35” 15.67 Libra
2023 Mar 27 14h 29m 35s -24° 38’ 26” 15.66 Libra
2023 Mar 28 14h 28m 54s -24° 51’ 12” 15.65 Libra
2023 Mar 29 14h 28m 13s -25° 03’ 52” 15.64 Hydra
2023 Mar 30 14h 27m 29s -25° 16’ 27” 15.62 Hydra
2023 Mar 31 14h 26m 43s -25° 28’ 57” 15.61 Hydra
2023 Apr 01 14h 25m 55s -25° 41’ 17” 15.61 Hydra
2023 Apr 02 14h 25m 05s -25° 53’ 32” 15.60 Hydra
2023 Apr 03 14h 24m 15s -26° 05’ 39” 15.59 Hydra
2023 Apr 04 14h 23m 21s -26° 17’ 39” 15.58 Hydra
2023 Apr 05 14h 22m 27s -26° 29’ 30” 15.57 Hydra
2023 Apr 06 14h 21m 30s -26° 41’ 12” 15.56 Hydra