Amateur astronomers capture Salsa and Samba dancing in the sky
25 July 2000
Two amateur astronomers from the Starkenburg observatory in Heppenheim,near Darmstadt in Germany, have succeeded in photographing the first twoCluster satellites, Salsa and Samba, during their daily dance around theEarth.The images were taken by Rainer Kresken, a flight dynamics engineer on the XMM mission at the European Space Operations Centre (ESOC) in Darmstadt, and his friend Matthias Busch, also an amateur astronomer.
"We persuaded some flight dynamics colleagues from Cluster, particularly ESOC colleague Siegmar Pallaschke, to predict the spacecraft's positions," said Rainer. "It took us several nights to catch them, partly due to bad weather, but on 20th July we succeeded."
Although the duo's first observations were hampered by moonlight and haze, their second viewing on the 22nd took place under ideal observing conditions.
"We took a series of CCD frames which we exposed for 5 or 10 seconds - one every minute," explained Rainer. "We observed the satellites near their apogee, about 120,000 km above the Earth, so they seemed to move quite slowly."
"We were overwhelmed that we could see them at this enormous distance," he added. "They were about magnitude 14 - surprisingly bright."
What made these amazing images possible was the previous observational experience by Rainer and his colleagues at the Starkenburg observatory. They spend most of their time at the 45 cm telescope searching for minor planets (asteroids) and following-up newly discovered Near Earth Objects with considerable success.
So far, more than 30 asteroids have been discovered by the team. Indeed, asteroid (6864) has been named Starkenburg in honour of their efforts, and the observatory team has been officially requested to propose names for more of the minor planets they have discovered.
The Cluster satellites were observed from the Starkenburg observatory in Heppenheim, south of Darmstadt, using a 0.45-m f/4.4 Newtonian reflector.
Observational data are:
20.07.2000
both spacecraft, start at 22:59 UTC
field of view: 11.7' x 20.9'
constellation: Aquarius
integration time per frame: 10 sec
range: about 124,000 km
apparent distance between spacecraft: 22.3'
22.07.2000
only Samba, start 23:01 UTC
field of view: 7.7' x 19.9'
constellation: Pegasus
integration time per frame: 5 sec
range: about 119,320 km
