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

Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of work by third parties is expressly forbidden without the consent of the copyright holder. By submitting images to this online gallery, you grant the BAA permission to reproduce them in any of our publications.

Registered charity no. 210769
Registered company no. 117572

For more information including contact details, click here.

Our Terms of Use are here.

Our Privacy Policy is here.