Astrophotography and projects.
How does one grind, polish and figure telescope optics at home?
The observatory dome, telescope mount, optical tube assembly and instrumentation.
Fine grinding 25 µm aluminium oxide
So many satellites
We humans have sent many tonnes of technology into orbit from 1957 to the present, - more than 5000 satellites.
During a 4.4 hour exposure covering 6.25 square degrees of sky, many old and new satellites cross the field.
Photo: RW Williams, 8-9 April 2019
Time: 20.55 - 02.28 UT
Equipment: Esprit 120 ED + Apogee U16M
Seventeen-pane mosaic, 5200 x 6500 pixels