Cees Bassa

@cbassa.bsky.social

582 Followers 141 Following

Astronomer at ASTRON in the Netherlands, working with the LOFAR low frequency radio telescope.

Three panels showing the altitude, velocity and acceleration of a spacecraft re-entering the Earth's atmosphere from lunar distances. For a narrow range of initial perigee altitudes does the spacecraft skip out of the atmosphere to lengthen the reentry.
CarbSAR on S-band.
A timelapse of 365 separate keograms taken over 2025, showing the motion of the Sun, Moon and stars.
A zoom of the 2025 keogram on the end of January, beginning of February, showing the motion of stars and planets.
A comparison of the 2024 keogram with predictions for set (dash-dotted line) and set (dotted line) of the Sun (in yellow) and the Moon (in red). The solid yellow line is when the Sun culminates in the South.
The year-long keogram for 2021.
The year long keogram on the right hand side is made up of 365 daily keograms, of which three on the right show differences throughout the year.
This video shows 24 hours worth of all sky images, with the pixel values along the red line concatenated in the keogram shown at the bottom.
Northern lights showing a red to green curtain high in the sky.
A daytime view from the camera, showing the Sun, blue sky and clouds.
The image shows the hourglass shape of the length of the day and night over the 365 days in 2025. Diagonal bands indicate when the Moon was up in the night sky.
The image shows the hourglass shape of the length of the day and night over the 365 days in 2025. Diagonal bands indicate when the Moon was up in the night sky.
Black smoke from the papal chimney.
This image shows the hourglass shape of the nights shortening and lengthening from winter to summer and from summer to winter, passing clouds, the Moon passing through the night sky every month (diagonal bands) and the Sun climbing higher in the sky during summer.