As it's at opposition this month, Neptune is a planet really worth seeking out in September 2026.
As the Solar System's outermost planet, distant Neptune yields few secrets from Earth.
It reaches opposition on 26 September, sitting directly opposite the Sun.
While closer planets like Mars grow dramatically brighter at opposition, Neptune’s extreme distance means its subtle increases in size and brightness are barely noticeable.
At magnitude +7.8, optical aid is essential. Binoculars can spot it, but a 150mm telescope best reveals its 2.4-arcsecond blue disc.
Under steady skies, a 200mm aperture easily captures its largest moon, Triton.
Currently located in Pisces, 9° west-southwest of Saturn, Neptune peaks highest (37° altitude) due south at 01:00 BST on 26 September.
Mercury
Evening planet, but unlikely to be seen this month as it’s too low after sunset.
Venus
- Best time to see: 1 September, 30 minutes after sunset
- Altitude: 1.7° (extremely low)
- Location: Virgo
- Direction: West-southwest
Evening planet shining at mag. –4.1 at the start of the month. Currently widely separated from the Sun in the sky, but very poorly placed from the UK. On 1 September, Venus sets 1 hour 12 minutes after sunset, but by the end of the month it sets with the Sun.
Mars
- Best time to see: 30 September, from 05:15 BST (04:15 UT)
- Altitude: 38°
- Location: Cancer
- Direction: East-southeast
Mars is a morning planet rising at around 01:00 BST (00:00 UT) at the start of the month. A waning crescent Moon sits nearby on the mornings of 6 and 7 September, Mars shining at mag. +1.2 at this time. Starting the month in Gemini, Mars concludes September in Cancer, 6° west of the Beehive Cluster, M44.
Jupiter
- Best time to see: 30 September, from 05:00 BST (04:00 UT)
- Altitude: 21°
- Location: Leo
- Direction: East
Jupiter is improving with every day that passes. Currently a morning planet in Cancer, on 1 September it rises 2.5 hours before the Sun. On the mornings of 8 and 9 September, a thin waning crescent Moon can be seen first to the west of Jupiter and then to the east of the planet in the dark morning twilight. If you’re an early riser, this should be an attractive sight given clear skies.
By the middle of the month, the offset from sunrise will have increased to 3.5 hours. By the end of September, Jupiter rises over 4.5 hours before the Sun and is able to reach a peak altitude of 27° under dark conditions. At this time, it shines at mag. –1.9 and can be found in Leo, having crossed the border on 24 September.
Saturn
- Best time to see: 30 September, 01:20 BST (00:20 UT)
- Altitude: 39°
- Location: Cetus
- Direction: South
Saturn is a morning planet, rising around 21:45 BST (20:45 UT) on 1 September, when it can be seen at mag. +0.5 in southern Pisces – although on 6 September it crosses the border into Cetus. It brightens throughout September, reaching mag. +0.3 on 25 September. The full Moon sits nearby on 27 September, a hint that opposition is not far away, this occurring on 4 October.
Uranus
- Best time to see: 30 September
- Altitude: 58°
- Location: Taurus
- Direction: South
Shining at mag. +5.7, Uranus is able to reach its peak altitude of 58° when due south under dark-sky conditions from 25 September onwards. Currently, the planet can be located near mag. +4.9 Omega (ω) Tauri.
Neptune
- Best time to see: 26 September, 01:00 BST (00:00 UT)
- Altitude: 37°
- Location: Pisces
- Direction: South
- Features: Small disc, blue colour, largest moon
- Recommended equipment: 150mm or larger
Read our full guide on observing Neptune in September 2026.
Share your observations and images with us by emailing contactus@skyatnightmagazine.com
