A short-period comet that goes round the Sun every 5.9 years, at perihelion about June 2028
Returns in June 2028. First in reach from Georgetown about 22 February to 18 November 2028, with binoculars.
Returns in June 2028. First in reach from Georgetown about 22 February to 18 November 2028, with binoculars.
From Lethem, under a dark interior sky: Returns in June 2028. First in reach from Lethem about 22 January 2028 to 4 January 2029, with binoculars.
It is not placed for viewing tonight. On its next best night from Georgetown, 25 June 2028, face south (azimuth 186 degrees) at 2:45 am GYT and look high up, 71 degrees up. It will be 140 degrees from the Sun.
A window is a run of nights on which it is at least 10 degrees up with the Sun at least 12 degrees down and its forecast brightness reaches a camera or better from Georgetown. The forecast is from how the comet behaved on past returns.
From 16 July to 17 October 2027 it is hidden in the Sun's glare from Georgetown: 94 nights.
| In reach | Best night | Best time | Height and direction | Gear on the best night | Forecast magnitude | Nights at each rung |
|---|---|---|---|---|---|---|
| 22 February to 18 November 2028 | 25 June 2028 | 2:45 am GYT | 71 degrees, south | Binoculars | about 5.1 (likely 4.1 to 6.1) | 45 binoculars, 72 small telescope, 154 camera |
Nobody has reported its brightness to COBS in the last 30 days, so every number here is a forecast.
The forecast comes from past returns (2009, 2015, 2022): a law fitted to 85 eye estimates before perihelion and 211 after, with the Earth's distance at the time removed and this return's put in. Comets do change between returns.
On its best night from Georgetown, 25 June 2028, it could be about 5.1 (likely 4.1 to 6.1), reading 5.1 through the air. Chance of the naked eye: about 4%. Binoculars: about 94%. A small telescope: near certain. The range is one standard deviation either side: about two forecasts in three land inside it.
A comet's light is spread over a fuzzy patch, so it is harder to see than a star of the same magnitude. That is why the gear rungs ask for a magnitude in hand.
Plan for 25 June 2028: aim at azimuth 186 degrees, altitude 71 degrees, at 2:45 am GYT.
On a fixed tripod keep each exposure short enough that the stars stay round, then stack many frames. For a long stack, align on the comet as well as on the stars: it drifts against them from frame to frame. A dark site adds more than any lens.
22P/Kopff passes closest to the Sun (perihelion) about 28 June 2028, at 1.320 au, where 1 au is the Earth's distance from the Sun. One orbit takes 5.87 years. The orbit is tilted 5.2 degrees to the Earth's and its eccentricity is 0.5947 (0 is a circle, 1 an open curve).
Orbit: NASA/JPL Horizons osculating elements, solution JPL#K283/2, retrieved 8 October 2026. Positions on this page are computed from them in your browser and agree with JPL's own tables to half an arcminute.
22P/Kopff is a short-period comet that goes round the Sun every 5.9 years. The "P" in 22P marks a periodic comet, and the number is the order in which its return was first confirmed.
Brightest eye estimate reported to COBS on each past return: 2009: magnitude 8.5, 30 days before perihelion, 1.61 au from the Sun and 1.24 au from Earth; 2015: magnitude 9.0, 10 days before perihelion, 1.56 au from the Sun and 2.04 au from Earth; 2022: magnitude 10.6, 111 days after perihelion, 1.90 au from the Sun and 1.65 au from Earth. How bright a return looks depends as much on how near the Earth it passes as on the comet.
Orbits: NASA/JPL Horizons (Giorgini, JD and the JPL Solar System Dynamics Group), data retrieved 2026-10-08.
Catalogue brightness laws: JPL Small-Body Database and the IAU Minor Planet Center.
Observed brightness: COBS Comet Observation Database (https://cobs.si) and its contributing observers, CC BY-NC-SA 4.0.
Data updated 8 October 2026. "Forecast" means: Not measured yet this return. Based on how this comet behaved on past returns.
Gear rungs and ranges are estimates for a typical observer: your eyes, your sky and the night will differ.