Introduction

The aims of this section are:

  • To encourage the observation of Saturn, Uranus and Neptune.
  • To provide help advice in the observation of these planets; for both beginners and experienced observers alike.
  • To follow changes in the atmospheres of these planets. 
  • To observe any phenomena involving Saturn’s rings. 
  • To observe any phenomena involving any of the satellites. 
  • To observe any stellar occultations by any of these planets or their satellites.

All observations are analysed and reported in the apparition reports for each planet which are published in the BAA Journal. A selection of the observations received is also shown in the Saturn, Uranus and Neptune Apparition Galleries.

Saturn, Uranus and Neptune are three of the four largest planets in our solar system. In size and mass they are only surpassed by the giant planet Jupiter.

Some information on each of these planets is shown in the following table.

SATURN

URANUS

NEPTUNE

Equatorial Diameter

120536 km 

51118 km

49528 km

Mass (times that of the Earth) 

95.2

14.5

17.2

Orbital Period

29.46 years

84.02 years

164.8 years

Average Synodic Period (Opposition to Opposition)

378.1 days

369.7 day

367.5 days

Apperant Angular Size 

14.5 to 20.1 arc seconds

3.3 to 4.1 arc seconds

2.2 to 2.4 arc seconds

Magnitude Range 

-0.55 to 1.17

5.38 to 6.03

7.67 to 8.

Number of Satellites

82

27

14

Saturn is the second largest planet in our solar system. Like Jupiter, it is designated as a gas giant. It is an easy object to see with the naked eye. It is most well known for its magnificent ring system which makes it one of the most spectacular objects visible in the sky. Indeed, the main rings can be detected with quite small telescopes. In addition, it has a large family of satellites, a few of which are visible with amateur telescopes.

Saturn resembles Jupiter in appearance with alternating dark and light bands. The darker bands are designated as belts and the lighter bands as zones. Sometimes the belts and zones show variations in intensity, colour and structure.

The section has been monitoring changes in the planet’s atmosphere for over a hundred years. Visual observations are still popular with many amateurs use imaging techniques and some are able to produce high resolution images of the planet with medium and large amateur instruments, This has allowed the evolution of the various storms that have appeared in the planet’s atmosphere.. 

The giant planets Uranus and Neptune are designated as ice giants. The magnitude of Uranus is just above the theoretical limit for naked eye visibility in very dark skies but is also easily found with binoculars. Neptune does require some optical aid to detect. 

Atmospheric features have been detected on both planets by spacecraft and large Earth-based telescopes. However the amateur detection of such atmospheric features is difficult due to the small angular sizes of these planets. Faint markings on Uranus have sometimes been reported by visual observations. Relatively recently, amateur imaging with suitable filters has allowed some larger scale features to be detected on the small apparent disks of both of these planets.

Membership of the section is open to open to all members of the British Astronomical Association. Correspondence is also welcome from anyone interested in these three planets.

Return to the Saturn, Uranus and Neptune Section home page 

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