C/2017 D2 (Barros)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	14 Jul 2017	15.4	2.500 AU	1.595 AU	22h01m	-33°53'	145.6°	13.3°	281°
Nearest approach	7 Aug 2017	15.3	2.514 AU	1.520 AU	21h39m	-29°21'	165.3°	5.9°	330°
Today	4 Aug 2025	30.1	20.387 AU	21.044 AU	06h01m	+50°51'	48.5°	2.1°	297°

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.)

The orbital elements of C/2017 D2 (Barros) are:

            e (Eccentricity)                : 0.9998490
            q (Perihelion distance)         : 2.5000880
            i (Inclination)                 : 31.25650
            Ω (Longitude of ascending node) : 330.95930
            ω (Argument of perihelion)      : 334.65390
            L (Longitude of perihelion)     : 308.91485
            B (Latitude of perihelion)      : -12.83362
            T (Time of perihelion passage)  : 2457948.99800

            Epoch                           : 2022 Jul 23
            Reference                       : MPC112391

            Classification(s):              : Nearly isotropic; New (a > 10000 AU)
        

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (11.00 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 10.40 + 5 log[∆] + 10.00 log[r]).

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.
A more printer-friendly version of the same chart can be found further down this page as well.

The following chart shows the current location of the comet in a smaller, upside-down telescopic field of view.

A printable version of the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-08-04 00:00 UT   06 01 21.2   +50 50 38    21.047   20.385   48.2    2.1   298   30.1 
2025-08-04 12:27 UT   06 01 28.8   +50 51 02    21.044   20.387   48.5    2.1   297   30.1 
2025-08-05 00:00 UT   06 01 35.9   +50 51 25    21.042   20.390   48.9    2.1   297   30.1 
2025-08-06 00:00 UT   06 01 50.4   +50 52 13    21.036   20.395   49.6    2.2   296   30.1 
2025-08-07 00:00 UT   06 02 04.8   +50 53 02    21.031   20.400   50.4    2.2   296   30.1 
2025-08-08 00:00 UT   06 02 18.9   +50 53 52    21.025   20.405   51.1    2.2   295   30.1 
2025-08-09 00:00 UT   06 02 32.9   +50 54 42    21.020   20.410   51.9    2.2   294   30.1 
2025-08-10 00:00 UT   06 02 46.6   +50 55 34    21.014   20.415   52.6    2.3   294   30.1 
2025-08-11 00:00 UT   06 03 00.2   +50 56 26    21.008   20.420   53.4    2.3   293   30.1 
2025-08-12 00:00 UT   06 03 13.6   +50 57 19    21.002   20.425   54.1    2.3   293   30.1 
2025-08-13 00:00 UT   06 03 26.7   +50 58 13    20.995   20.430   54.9    2.3   292   30.1 
2025-08-14 00:00 UT   06 03 39.7   +50 59 08    20.989   20.435   55.6    2.3   291   30.1 

    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.