070607 Jupiter...

Canopus Lim · Post by **Canopus Lim** » Fri Jun 08, 2007 12:11 am

Tonight the seeing and transparency is very good. I was observing Jupiter and this is the first time I saw a 'half shadow transit'.

Scope: 12.5" Obsession
Eyepiece: 5mm Baader Genuine Orthoscopic (317x)

Io was crossing the face of Jupiter (about the equator region) and the moon was whitish colour and stood out very well from Jupiter. I saw its shadow on Jupiter and it was a half of a shadow; the shadow was 'attached' to Io and moved with it as Io moved. Cool..

The seeing was very good, and I could easily see more than 10 belts on Jupiter and 2 distinct white ovals at the South. A lot of details in the equator and southern side. The image was sharp and had high contrast at 317x and the moons had little seeing effects on them at such magnification. I also managed to glimpse (flickering) details on Ganymede. The detail was a darken region on the moon.

However, I could not see the detail too clearly as it was flickering on off. Therefore, if the seeing is very good, details can be seen visually on the moons with such a scope.

mrngbss · Post by **mrngbss** » Fri Jun 08, 2007 8:37 am

That's good for you! my side at Bishan was all so cloudy...

Canopus Lim · Post by **Canopus Lim** » Fri Jun 08, 2007 9:01 am

The clouds were moving north and came from the sea, so no wonder Bishan was clouded. At 11.30, I packed up as it became very cloudy. Before 11.30, it was generally very clear but I could not observe DSOs because my neighbour's lights were just too bright. However, despite the brightness of the lights surrounding me, I could pick up Mag 3.9 stars. Hence if the lights, street lights and neighbour's light...could be turned off, I won't be surprised to see near Mag 5 stars.

Canopus Lim · Post by **Canopus Lim** » Sat Jun 23, 2007 10:06 pm

Now I realised why I saw Io's shadow so close to it. I think the observing time was near to Jupiter's opposition, so the sun is almost directly shining at the face of Io that is why the shadow was 'half' and 'attached' to Io.

If at opposition will the moons have no shadow at all, assuming the sunlight is shining really face on the moons, let say the moon is really at transit (centre of Jupiter)?? Anyone seen such shadow transits during opposition?