A long-period comet, at perihelion about November 2028
Hidden in the Sun's glare from Georgetown until about 4 March 2028.
Hidden in the Sun's glare from Georgetown until about 4 March 2028.
Tonight it does not climb 10 degrees above the horizon while the sky is dark from Georgetown.
From Lethem, under a dark interior sky: Hidden in the Sun's glare from Lethem until about 25 December 2027.
It is not placed for viewing tonight. On its next best night from Georgetown, 1 June 2028, face south-west (azimuth 234 degrees) at 7:09 pm GYT and look halfway up, 41 degrees up. It will be 80 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 an early estimate from a catalogue law.
From 8 to 23 October 2026 it is hidden in the Sun's glare from Georgetown: 16 nights.
From 23 August to 19 October 2027 it is hidden in the Sun's glare from Georgetown: 58 nights.
| In reach | Best night | Best time | Height and direction | Gear on the best night | Forecast magnitude | Nights at each rung |
|---|---|---|---|---|---|---|
| 4 March to 8 July 2028 | 1 June 2028 | 7:09 pm GYT | 41 degrees, south-west | Camera | about 10.5 (likely 8.4 to 13.7) | 127 camera |
| 19 September to 17 October 2028 | 15 October 2028 | 4:53 am GYT | 11 degrees, south-east | Small telescope | about 5.7 (likely 2.8 to 10.1) | 25 small telescope, 4 camera |
| 12 November 2028 to 4 January 2029 | 20 November 2028 | 6:35 pm GYT | 26 degrees, south | Binoculars | about 5.2 (likely 2.3 to 9.6) | 37 binoculars, 17 small telescope |
Nobody has reported its brightness to COBS in the last 30 days, so every number here is a forecast.
No one has followed this comet through a return like this one, so the forecast is a catalogue estimate with a wide range. It looks like a first-time visitor from the outer Solar System, and those usually brighten more slowly than their early numbers suggest.
On its best night from Georgetown, 1 June 2028, it could be about 10.5 (likely 8.4 to 13.7), reading 10.6 through the air. Chance of the naked eye: about 1%. Binoculars: about 11%. A small telescope: about 24%. 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 1 June 2028: aim at azimuth 234 degrees, altitude 41 degrees, at 7:09 pm 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.
C/2026 C1 (Tsuchinshan) passes closest to the Sun (perihelion) about 6 November 2028, at 1.150 au, where 1 au is the Earth's distance from the Sun. Its orbit is so stretched that it will not return in our lifetimes. The orbit is tilted 99.7 degrees to the Earth's and its eccentricity is 0.9999 (0 is a circle, 1 an open curve).
Orbit: NASA/JPL Horizons osculating elements, solution JPL#19, 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.
C/2026 C1 (Tsuchinshan) is a long-period comet. The "C/" marks a comet that is not known to return within 200 years; the year and letters record when it was found.
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. "Early forecast" means: A catalogue estimate. Early predictions are often wrong in both directions.
Gear rungs and ranges are estimates for a typical observer: your eyes, your sky and the night will differ.