Your guide to the Solar System and the night sky
Please donate now to help keep TheSkyLive ads-free. This site cannot run without your voluntary donations.
🌎  Greenwich, United Kingdom [change]

Comet 77P/Longmore

Comet 77P/Longmore is currently in the constellation of Lynx. The current Right Ascension of Comet 77P/Longmore is 08h 04m 49s and the Declination is +52° 35’ 07” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom [change]). The current estimated magnitude of Comet 77P/Longmore is 19.54 (JPL).

Summary of key facts about Comet 77P/Longmore [tip: you can also create a Quick Access page for this data if you access it frequently and would like to have a simpler view]:

08h 04m 49s
+52° 35’ 07”
  • 77P/Longmore is above the horizon from Greenwich, United Kingdom [change].
  • It is visible looking in the North-West direction at an altitude of 26° above the horizon.
  • Given its current magnitude, 77P/Longmore is visible only through long exposure photography.
  • See also 77P/Longmore rise and set times.
  • 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.

Additional information about Comet 77P/Longmore available on TheSkyLive:

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 Lynx on December, 09 2021
Field of view: 50x30 degrees
View fullscreen
Map showing Comet 77P/Longmore in Lynx on December, 09 2021
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: 08h 04m 49s
Dec: +52° 35’ 07”
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 423,804,303 kilometers, equivalent to 2.832957 Astronomical Units. Light takes 23 minutes and 33.6590 seconds to travel from Comet 77P/Longmore and arrive to us.

23 minutes and 33.6590 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.

Distance of Comet 77P/Longmore from Earth between January 2013 and December 2100

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 January 2013 and December 2100, the closest approach of Comet 77P/Longmore to Earth happens on Sun Apr 22 2063 at a distance of 1.005967 Astronomical Units, or 150,490,463 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 19.54.


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.

Predicted magnitude of Comet 77P/Longmore between January 2013 and December 2100

Comet 77P/Longmore rise and set times

Location: Greenwich, United Kingdom [change]
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

Comet 77P/Longmore is circumpolar and transits at 02:52 UTC (altitude: 88.9°)

The rise and set times are defined as the time at which the upper limb of Comet 77P/Longmore touches the horizon, considering the effect of the atmospheric refraction. As the atmospheric conditions cannot be modeled precisely the times reported here should be considered correct with an approximation of few minutes.

Comet 77P/Longmore Orbital Elements

The following table lists the orbital elements of Comet 77P/Longmore at epoch 26 August 2010 00:00 UTC (JD: 2455435.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.35787590
Orbit inclination i 24.39945385°
Perihelion distance q 2.31145812 AU
345,789,213 km
Aphelion distance Q 4.88795431 AU
731,227,558 km
Semi-major axis a 3.59970621 AU
538,508,385 km
Orbital period period 6.8298 years
2,494.5891 days
Date of perihelion transit Tp 2009-Jul-08 00:09:53
2,455,020.5069 JD
Next perihelion transit 2016-May-06 14:18
2,457,515.0959 JD
Argument of perihelion peri 196.77265024138°
Longitude of the ascending node node 14.911972579259°
Mean anomaly M 59.888631793644°
Mean motion n 0.14431235°/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
2021 Dec 02 08h 08m 07s +51° 38’ 53” 19.64 Lynx
2021 Dec 03 08h 07m 46s +51° 46’ 32” 19.63 Lynx
2021 Dec 04 08h 07m 24s +51° 54’ 11” 19.62 Lynx
2021 Dec 05 08h 07m 00s +52° 01’ 46” 19.60 Lynx
2021 Dec 06 08h 06m 34s +52° 09’ 21” 19.59 Lynx
2021 Dec 07 08h 06m 06s +52° 16’ 54” 19.57 Lynx
2021 Dec 08 08h 05m 36s +52° 24’ 24” 19.56 Lynx
2021 Dec 09 08h 05m 04s +52° 31’ 50” 19.55 Lynx
2021 Dec 10 08h 04m 31s +52° 39’ 15” 19.53 Lynx
2021 Dec 11 08h 03m 55s +52° 46’ 33” 19.52 Lynx
2021 Dec 12 08h 03m 16s +52° 53’ 49” 19.51 Lynx
2021 Dec 13 08h 02m 38s +53° 01’ 00” 19.50 Lynx
2021 Dec 14 08h 01m 55s +53° 08’ 05” 19.48 Lynx
2021 Dec 15 08h 01m 11s +53° 15’ 06” 19.47 Lynx