C/2021 R7 (PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	17 Apr 2021	22.1	5.655 AU	6.636 AU	01h26m	+21°11'	11.3°	2.0°	338°
Nearest approach	30 Sep 2021	21.5	5.779 AU	4.793 AU	00h30m	+13°45'	169.1°	1.9°	185°
Today	5 Mar 2026	27.2	12.854 AU	13.485 AU	20h16m	-37°01'	48.8°	3.3°	241°

The interactive orbit chart above shows the comet's path through the solar system and its position at the given date. Green and blue lines are shown perpendicular to the ecliptic plane: Green if the path is above the ecliptic plane, blue if it is below. (Left-click and drag to rotate the view; Right-click and drag to move the view; Use scroll wheel to zoom in our out.)

Light curve

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations from COBS. The light curve is based on the absolute magnitude and slope parameter as calculated from an MPEC, or the latest values provided by the minor planet center. (10.5 + 5 log[∆] + 10.0 log[r]). An additional green curve is displayed when an increase in apparent brightness is expected due to forward scattering of sunlight, which occurs when a dust-rich comet is located between the Earth and the Sun. (See Marcus 2007)

Charts

The all-sky chart below shows the path of the comet over the same period as the light curve. The comet's current position is marked yellow.

The following chart shows the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Orbital elements

The orbital elements of C/2021 R7 (PANSTARRS) are:

    e (Eccentricity)                : 0.9948510
    q (Perihelion distance)         : 5.6547510
    i (Inclination)                 : 158.88130
    Ω (Longitude of ascending node) : 170.22590
    ω (Argument of perihelion)      : 140.43780
    L (Longitude of perihelion)     : 207.84637
    B (Latitude of perihelion)      : 13.26655
    T (Time of perihelion passage)  : 2459322.34780
    P (Orbital period in years)     : 36394.51

    Epoch                           : 2026 Mar 04
    Reference                       : MPEC 2022-X67

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-03-04 00:00 UT   20 16 20.9   -37 00 33    13.495   12.847   47.6    3.3   240   27.2 
2026-03-05 00:00 UT   20 16 31.8   -37 01 14    13.488   12.852   48.5    3.3   241   27.2 
2026-03-05 09:59 UT   20 16 36.2   -37 01 32    13.485   12.854   48.8    3.3   241   27.2 
2026-03-06 00:00 UT   20 16 42.4   -37 01 57    13.481   12.857   49.4    3.4   241   27.2 
2026-03-07 00:00 UT   20 16 52.8   -37 02 42    13.474   12.862   50.3    3.4   242   27.2 
2026-03-08 00:00 UT   20 17 02.9   -37 03 28    13.466   12.867   51.2    3.4   242   27.2 
2026-03-09 00:00 UT   20 17 12.8   -37 04 16    13.458   12.872   52.1    3.5   243   27.2 
2026-03-10 00:00 UT   20 17 22.4   -37 05 05    13.451   12.877   53.0    3.5   243   27.2 
2026-03-11 00:00 UT   20 17 31.8   -37 05 57    13.443   12.883   53.9    3.6   244   27.2 
2026-03-12 00:00 UT   20 17 40.9   -37 06 50    13.434   12.888   54.8    3.6   244   27.2 
2026-03-13 00:00 UT   20 17 49.7   -37 07 44    13.426   12.893   55.7    3.7   244   27.2 
2026-03-14 00:00 UT   20 17 58.3   -37 08 40    13.417   12.898   56.6    3.7   245   27.2 
2026-03-15 00:00 UT   20 18 06.6   -37 09 38    13.409   12.903   57.5    3.7   245   27.2 

    Terminology:
            
    delta:  distance between comet and earth in AU
    radius: distance between comet and sun in AU
    magn:   magnitude (brightness) estimate    
    ra:     right ascension in hours (24h = 360deg)
    dec:    declination in degrees
    elong:  elongation in degrees (angle sun-earth-comet)    
    phase:  phase angle in degrees (angle sun-comet-earth)        
    AU:     Astronomical Unit (mean distance between earth and sun: 149597870.7 km      
    

Orbital elements usually provided by the MPC (Minor Planet Center).
Observations contributed by observers worldwide, via COBS (Comet Observation Database) or the MPC (Minor Planet Center)
Calculations by a modified version of AAPlus, a C# implementation of the AA+ project by PJ Naughter from the algorithms presented in the book "Astronomical Algorithms" by Jean Meeus.
NGC2000 dso catalog and star labels from VizieR as provided by the Strasbourg astronomical Data Center.
Tycho2 catalog from the ESO archive.