Comet 29P/Schwassmann–Wachmann, also known as Schwassmann–Wachmann 1, was discovered on November 15, 1927, by Arnold Schwassmann and Arno Arthur Wachmann at the Hamburg Observatory in Bergedorf, Germany. Outbursts are very sudden, rising to maximum in about 2 hours, which is indicative of their cryovolcanic origin; and with the times of outburst modulated by an underlying 58-day periodicity possibly suggesting that its large nucleus is an extremely slow rotator.

thumb|left|550px|Comet 29P after outburst, this is a stack of 20 images centered on the comet's movement, frames taken with a 0.40m telescope F10 + CCD at La Cañada Observatory (MPC-J87) 04-Oct-2008 02:24 UT the stacked images have been Larson–Sekanina filtered to enhance the details, on the left a radial process with delta = −1 px to better show the expanding shells of gas and dust, on the right a rotational gradient with alpha=15 degrees displaying various jets.

During 2025, there were 8 notable outbursts occurring as four pairs of twin events: January 2/6, February 1/2, May 13/25, and December 4/11. The December outburst reached about magnitude 13.

In 2026, there was an outburst on February 9/15 to magnitude 12.6V. On April 15 there was outburst from magnitude 16 to 13.

References

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  • 29P/Schwassmann–Wachmann 1 – Seiichi Yoshida @ aerith.net
  • 29P/Schwassmann–Wachmann – cobs.si
  • 29P monitoring campaign – British Astronomical Association COMET MISSION 29P website
  • 29P at Las Cumbres Observatory (8 Feb 2010 12:23, 60 seconds)
  • 29P (Joseph Brimacombe April 18, 2013)