The comet 21P/Giacobini-Zinner
From Cambridge , 21P/Giacobini-Zinner is visible between 00:20 and 04:57. It will become accessible around 00:20, when it rises to an altitude of 22° above your south-eastern horizon. It will reach its highest point in the sky at 02:39, 29° above your southern horizon. It will become inaccessible around 04:57 when it sinks below 22° above your south-western horizon.
Object Type Comet
|Magnitude:||21.78 (V) |
|Absolute mag (H):||9.40 |
|Slope parameter (n):||5.84 |
|Right ascension:||10h58m |
31.73 lightmin 
|Semi-major axis:||3.50 AU|
|Longitude ascending node:||195.38°|
|Argument of perihelion:||172.85°|
|Epoch of elements:||21 January 2020|
|Mean Anomaly at epoch:||75.03°|
|Orbital period:||6.54 years|
Where possible, the brightnesses of comets are estimated from absolute magnitude values computed by the BAA Comet Section, based on the observations they receive. We prefer these to the Minor Planet Center's own magnitude estimates, since the latter are less often updated. Nonetheless, comets are intrinsically unpredictable objects, and magnitude estimates must always be taken with a pinch of salt.