10P Tempel

Closest to Sun: 2026 August 2 at 1.41AU
Closest to Earth: 2026 August 3 at 0.41AU

Maximum magnitude 8.0 in early August 2026

Comet 10P Tempel on 2026 August 10, when at its brightest. Note the dust trail.

Comet 10P Tempel, a Jupiter-family comet which orbits the Sun every 5.37 years, will make its most impressive appearance since 1967
—and the best of the 21st century—in 2026. Be sure to make the most of this remarkable event.
During the first week of August 2026, it will be at its closest point to both Earth and the Sun simultaneously.
It will reach opposition in the constellation Capricornus, its southerly declination making it more favourable for observers in the southern hemisphere.
Its brightness is expected to peak at magnitude 8.0 during this time.

10P Tempel, also known as Tempel 2 (old designation) , was discovered by Wilhelm Tempel on 4 July 1873
and has been observed at 24 of the past 29 returns.
At its last fine appearance in 1967, it reached a total magnitude of 8.0 and a similar peak is expected this year.
The comets nucleus is estimated to be about 10kms across, similar to 1P Halley.

On July 21, the Earth will cross the orbital plane of the comet. 10P is known to have one of the largest dust trails of any comet.
At its 2010 appearance, the faint trail was photographed at least 10 degrees away from the nucleus!
Current CCD/CMOS technology should be able to image this one again without too much difficulty.

During May 2026,
The comet can be seen in the constellation of Aquila, rising during the late evening hours but best observed during the early hours of the morning.
It is expected to brighten from magnitude 12.5 to magnitude 10.5 by month's end.
Moon free observing during the evening hours occurs from May 9 for the next couple of weeks.

During June 2026
the comet continues its easterly trek through the constellations of Aquilla, Capricornus and Aquarius,
brightening from magnitude 10.5 to 9.0 by month's end.
Moon free observing during the evening hours commences from June 7.
A tremendous deep sky rendezvous with the Saturn nebula NGC 7009 occurs between June 28 to July 1
with the comet passing about 45 arc minutes to the south of it on June 30, however moonlight will be a problem.


10P Tempel on July 6

During July 2026
the comet commences a south-easterly trek through the constellation of Aquarius and Capricornus,
brightening from magnitude 9.0 to 8.0 by month's end.
Moon free observing during the evening hours commences from July 4.
Note that on July 21, the Earth crosses the orbital plane of the comet. 10P is known to have a very large dust trail.
The position angle of the trail is expected to appear in PA 321 and 143.
The visibility of the trail is expected to last several nights, centered around July 21, but recommended to image the trail after moonset.

During August 2026
the comet, at its brightest, continues its south easterly trek through the constellation of Pisces Austrinus.
Fortunately, moonlight will not interfere with the comets primetime viewing during the first two weeks of August.
The comet transits virtually overhead for observers situated at 35° S latitude around local midnight.
Moonlight interferes during the second half of August. By months end the comet will have faded slightly to magnitude 8.5.

During September 2026
 the comet will start to trek more easterly and northeasterly through the constellation of Pisces Austrinus.
fading from magnitude 8.5 to magnitude 9.5 by months end. Moon free observing commences on September 1.


10P Tempel on 2026 September 9

During October 2026
 the comet continues its northeasterly trek through the constellation of Pisces Austrinus and Sculptor,
fading from magnitude 9.5 to 11.0.
The first two weeks of October offer the best viewing without moon interference.
On October 5 the comet situates adjacent to gamma PsA and on October 8, sits adjacent to Delta PsA.
Get your last views of the comet for this apparition as it won’t be as favourable for a long time, 2042 offering the next semi-favourable show.