New Comet C/2025 J1 (Borisov) Discovered in May 2025

A new comet, designated C/2025 J1 (Borisov), has been discovered by famous Crimean comet hunter Gennady Borisov, who is also known for the discovery of 2I/Borisov, the first-ever known interstellar comet.

Complete visibility information and finder charts for Comet C/2025 J1 (Borisov) can be found on its dedicated page on TheSkyLive.

Discovery

Gennady Borisov discovered C/2025 J1 on CCD images captured on the night between May 2 and May 3, 2025, using a 0.50-m f/1.9 astrograph at his observatory in Nauchnij, Crimea.

As described in the original CBAT announcement, in the initial observations, the comet had a coma approximately 1.5 arcseconds in diameter and a broad tail stretching 7 arcseconds towards position angles 250-260 degrees. The total magnitude was reported as a faint 19.3, measured within a 0.25 arcminute aperture. Subsequent observations by Borisov revealed the tail had extended to 9 arcseconds, spanning position angles 210-240 degrees.

Following its posting on the Minor Planet Center's Possible Comet Confirmation Page (PCCP), other observers confirmed its cometary nature. Notably, P. Birtwhistle (Great Shefford, Berkshire, England) on May 5.9 UT, using a 0.41-m reflector, imaged a very condensed head of 4 arcseconds with a 20-arcsecond tail pointing towards p.a. 230 degrees.

Pre-discovery observations were later identified from images taken on April 29 and May 2 by the Zwicky Transient Facility (ZTF) survey using the 1.2-m Schmidt telescope at Palomar Observatory, showing the comet at magnitude 19.6-20.1.

Designation

As explained in How Newly Discovered Comets Are Named, the designation of C/2025 J1 has the following meaning

• "C/" indicates a long-period comet or one on a non-periodic trajectory.
• "2025" is the year of discovery.
• "J" identifies the half-month of discovery (A=first half Jan, B=second half Jan ... J=second half May).
• "1" means it's the first comet discovered in that half-month.

Interesting Facts About C/2025 J1 (Borisov)

The image below shows the orbit of C/2025 J1 and its position at the time of its discovery:

As this orbit diagram shows, C/2025 J1 trajectory has two interesting features:

• Distant Perihelion: Comet C/2025 J1 (Borisov) will make its closest approach to the Sun (perihelion) on June 11, 2026. This closest approach will occur at a considerable distance of approximately 3.576 Astronomical Units (AU) (about 535 million km or 332 million miles), which places the comet's perihelion well beyond the orbit of Mars, and in the vicinity of the outer asteroid belt.
• Highly Inclined Orbit: The comet has a significantly high orbital inclination of approximately 95.44 degrees. This means its path is tilted almost perpendicularly to the ecliptic plane, the plane in which most planets in our Solar System orbit the Sun.

Incidentally, because its large inclination, Comet C/2025 J1 was discovered close to the Northern Celestial Pole and, around May 21st 2025, the comet will transit close to the Polaris star, as shown in the image below.

C/2025 J1 (Borisov) Visibility

Based on the current estimations, C/2025 J1 is predicted to be at its brightest, around magnitude 17.2-17.7, for an extended period from approximately February 2026 to November 2026. Its actual perihelion occurs on June 11, 2026.

The comet will remain well positioned for Northern Hemisphere visibility until August 2026. It will then move to lower declinations and become to be more easily visible from the Southern Hemisphere during 2027.

Additional Resources About C/2025 J1

• Comet C/2025 J1 (Borisov): Complete reference information on TheSkyLive.com
• Where is Comet C/2025 J1 (Borisov)?: Key information on locating Comet C/2025 J1 (Borisov) in the sky.
• Distance from Earth: Find out how far Comet C/2025 J1 (Borisov) is from Earth right now.
• How Bright is Comet C/2025 J1 (Borisov)?: Current visual brightness (magnitude) and apparent size.
• Rise and Set Times: Comet C/2025 J1 (Borisov)'s rise and set times from your location.
• Interactive Sky Map: planetarium-style interactive visualization of Comet C/2025 J1 (Borisov)'s position in the sky.
• Live Position Tracker: high precision position tracker with deep space imagery.
• Ephemeris: 15 days Comet C/2025 J1 (Borisov)'s computed ephemeris.
• Orbital elements: information about Comet C/2025 J1 (Borisov) orbital parameters.
• Orbit Visualization. 3d interactive visualization showing the orbit of Comet C/2025 J1 (Borisov) with respect to the major Solar System objects.