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Posted (edited)

Few days ago I decided to observe the spectra around Na lines for Jupiter and Saturn. I had a little time and some problems with Bluetooth communication. It took me about 30 min. 
About 3 am the sky was getting brighter. I set 20 μm slit of my Low Spec spectrograph along the equator:


These images were taken few years ago.

1, 2, 3 - positions of spectral profiles

The goal was to record the impact of planetary rotation on the shape of spectral lines. Interestingly, the spectra contain not only the inclined lines created due to the Doppler effect.
There are also visible vertical absorption lines of the Earth's atmosphere, there are quite a few of them.

Below two stacks of Na doublet area, resize 200%:

Spectral profiles for Jupiter:


Spectraf profiles for Saturn Rings:


The result of calculations of the rotational velocity at the equator and comparison with data in the public literature:

Result of calcutations
  Jupiter Saturn
Rotational velocity 13.2 ± 1.3 km/s 10.5 ± 1.3 km/s
Equatorial diameter 149890 km 128744 km
Public literature
  Jupiter Saturn
Rotational velocity 12.6 km/s 9.87 km/s
Equatorial diameter 142984 km 120536 km

The velocity of Saturn's rings is variable, the rings closest to the planet have the highest velocity, the furthest rings are the slowest.
The calculated average velocity based on the recorded spectrum is 15.8 km/s.
As an example, the velocity of the crumbs moving on the outside of the Cassini Break (ring A) is 17.5 km/s. Pretty close.

I took half a pixel as a measurement error.

Edited by Bajastro
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