Observation by Chris Hooker: Io's sodium clouds, 21st March 2026

Uploaded by

Chris Hooker

Observer

Chris Hooker

Observed

2026 Mar 21 - 19:41

Uploaded

2026 Mar 23 - 20:29

Objects

Jupiter

Equipment

110 mm ED APO refractor
0.45x re-imaging focal reducer
Alluxa 589.2 nm 2.1 nm bandpass filter
Thorlabs 570 nm 10 nm bandpass filter
ZWO ASI178MM camera

Exposure

4 x 180 seconds

Location

Didcot, Oxfordshire

Target name

Jupiter & moons

Title

Io's sodium clouds, 21st March 2026

About this image

Two images of the Jovian system showing Io's sodium clouds. The upper image has been slightly stretched to show the "banana" cloud in the plane of Io's orbit and part of the stream of sodium stripped from Io's atmosphere by the action of the plasma torus. The lower image has had a greater contrast stretch to bring out the fainter parts of the stream.

Four 3-minute images through the sodium filter and four 41-second images through the off-band filter were stacked in Autostakkert!. The off-band image was subtracted from the sodium image to remove atmospheric scatter around Jupiter, leaving the sodium emission more visible. Jupiter was attenuated by a strip of Baader solar filter with a density of 3.8 (6,300 x attenuation).

The moons are indicated by their initial letters. Io was near western elongation, and Europa was about to be occulted by Jupiter.

Files associated with this observation

Io sodium clouds 21 Mar 26.png (639.7 kB)

Like this image

Geof Lewis, Andy Wilson, Dominic Ford, Adam Rawlinson

Comments

Adam Rawlinson, 2026 Mar 27 - 09:43 UTC

Thats really impressive. Im studying Io's volcanism at the moment. Its great to see direct evidence of the torus on ejected matter as well as elemental make up of the trail. Have you tried any other narrow band imaging other than sodium? I wonder if Sulphur detection also might be feasible?

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