On August, 27, Jupiter (Zeus) almost had an affair with Venus! Juno (Zeus' wife) -- disguised as a spacecraft sent by NASA -- took a picture of her husband on that date (seen here: http://www.jpl.nasa.gov/news/news.php?feature=6606
), but Venus was not visible in that picture!
I believe this clearly demonstrates how Zeus misbehaved in the Ancient Greek Mythology, and how Zeus could meet beautiful earthly women without Juno noticing it!
Well, I also collected NASA/JPL ephemeris data that hints at Venus running away from Jupiter!
So I decided to observe this, to prove that Venus was in fact running towards the Earth faster (-7.55 km/s) than Jupiter (+10.14 km/s). I wanted to fit Jupiter and Venus on the same slit of my spectrograph and measure radial velocity! They got really close to each other from my longitude before setting (8 arc-minutes, at time of observation).
My goal: observe a differential radial velocity between Venus and Jupiter of +17.7 km/s! (the real challenge here is in characterizing the distortion of the spectrum in my Lhires)
Due to unforeseen problems, I could not use the right telescope (focal distance) necessary, so I had to observe both planets separately!
I quickly discovered the effect of a dimmer Jupiter compared to Venus, and the atmosphere was unstable (5 degrees above horizon!!).
Since I now had to observe both planets separately, I decided to orient the slit with East-West, to measure Jupiter's equatorial rotation!
Dateikommentar: Spectrum around H-alpha, LhiresIII 2400 Atik-414
jv_v0.jpg [ 69.08 KiB | 793 mal betrachtet ]
From the separate spectra of both planets, I could not visibly detect any shift in the lines reflecting on Venus.
From Jupiter, however, it seems to be spinning at 9 km/s (mabye I did not have the slit precisely at the equator). But because I can estimate that Jupiter is in fact moving away (redshift) at very close to 10 km/s!
However, I was expecting to see Venus move towards the observer at 7.69 km/s, and I could not detect any visible shift in the lines!