Well, after a couple of months battling the poor weather and inconvenient E or W elongations of Mimas, not to mention waiting for Phoebe and Iapetus to move closer to fit in a single frame, I managed to record all the classical moons of Saturn from our back garden in Brisbane on the night of 14th June 2013.
I took a series of 5 sec, 30 sec, 60 sec, 120 sec and 300 sec exposures with the SBIG ST2000XM to cover the brightness range of the various objects and an AVI with the ASI120MM to record Saturn. Out of the 20 SBIG ST2K frames taken to chase down Mimas, 3 clearly showed the mag 13.1 satellite whereas the remainder had less certainty due to the overwhelming glare from Saturn’s disc and ring system. Mimas was at Eastern Longation at approx. 9:28pm.
Saturn Details:- Magnitude: 0.42
- Size: 42"x 16"
- Earth Distance: 9.1 AU
- Sun Distance: 9.8 AU
- Diameter: 120536.0 km
- Apparent Altitude: +65°
Satellite Details:- Name Mag PA° Sep"
- Mimas 13.1 92.2 27.9
- Enceladus 11.9 273.6 34.8
- Tethys 10.4 269.9 44.5
- Dione 10.6 97.5 51.7
- Rhea 9.9 129.4 34.2
- Titan 8.5 290.2 121.1
- Hyperion 14.4 128.0 98.1
- Iapetus 11.3 314.5 246.4
- Phoebe 16.7 99.6 352.3
Saturn, the sixth planet from the sun, is home to a vast array of intriguing and unique worlds. From the cloud-shrouded surface of Titan to crater-riddled Phoebe, each of Saturn's moons tells another piece of the story surrounding the Saturn system.
Christiaan Huygens discovered the first known moon of Saturn. The year was 1655 and the moon was Titan. Giovanni Domenico Cassini made the next four discoveries: Iapetus (1671), Rhea (1672), Dione (1684), and Tethys (1684). Mimas and Enceladus were both discovered by William Herschel in 1789. The next two discoveries came at intervals of 50 or more years -- Hyperion (1848) and Phoebe (1898).
As telescopic resolving power increased through the 19th century, Saturn's family of known moons grew. In 1966 Epimetheus and Janus were discovered. By the time Cassini-Huygens was launched in 1997, Saturn's moon count had reached 18. The number of known moons soon increased with high-resolution imaging techniques used on ground-based telescopes. The Cassini mission has discovered several more moons since its arrival at Saturn.
62 moons have been discovered in orbits around Saturn, and 53 of them have been officially named.
Titan is so large that it affects the orbits of other near-by moons. At 5,150 km (3,200 miles) across, it is the second largest moon in the solar system.
Equipment Details:- Tak Mewlon 180 F12
- Tak x1.6 Extender giving and efl of 3456mm at F19.2
- SBIG ST2000XM CCD camera
- Brisbane, Qld, Australia.
- 14th June 2013, between 9:39 and 10:12 pm AEST (UT+10).
- Images calibrated and aligned in CCDStack, with finishing in Photoshop CS6.
The final image is not “true” in the sense that the satellites moved in their orbits during the time it took to record all the frames and I have also made non-linear brightness adjustments to the objects to display them in the same composite frame.
I have attached the inventory of frames used in the exercise along with screen captures from SkyTools 3 Professional Edition and The Sky X, the latter gives an incorrect position of Iapetus whereas Starry Night Pro Plus 6 gives an incorrect position for Phoebe. Sky Safari Pro for the iPad agrees with SkyTools and provided the correct positions.
Cheers
Dennis
