Planetary Moons – Page 5 – Astronomy Sketch of the Day

Backyard Jupiter

Object Name: Jupiter
Object Type: planet
Location: Itajobi – SP – Brazil
Date: 2010, July 20th
Time: 04h30min – U.T.
Media: colored pencil on white paper, photographed with Sony Cybershot 4.1MP (Carls Zeiss lens), edited with Paint.
Telescope: reflecting 180mm f/D=6 (dobsonian)
Eyepieces: SP 32mm (34x); Plossl 10mm (108x); SP 6mm (180x)
Observer: Rodrigo Pasiani Costa
Extra information:
That was a cloudy, cold night – for us, Brazilian people – around 12ºC. I had just aligned my mirrors and wanted to test the collimation. After one hour observing the moon through dark clouds, I saw the best picture of Jupiter ever (through my telescope) that night. Even through the 32mm eyepiece I could see two dark stripes crossing the giant planet, which was surrounded by its four brighest moons. Through the 10mm I got my best view, like the sketch. The 6mm eyepiece showed a low-resolution, distorted image. No filter used. I’d like to thank to Gabriel Piani Luna da Silva, that helped me with the telescope that afternoon, and also lent his backyard that night. It was his first time observing Jupiter, and he got impressed. I couldn’t forget to thank his mother, who gave us a delicious cake that afternoon, while we were fixing the telescope mounting. This is my first Jupiter sketch, I hope you enjoy it.

Best regards and clear skies to everybody,

Rodrigo Pasiani Costa

Dancing in the Royal Court

Jupiter moon Europa has just transited Ganymede, November 17, 2009
Sketch and Details by Michael Rosolina

Because of the geometry of Earth’s orbit in relation to Jupiter’s orbit, this has been a very good year for seeing transits across the Jovian disk. Not only have there been numerous transits of the Galilean moons and their shadows, the moons themselves have been transiting and occulting one another as seen from our vantage point here on Earth.

In this sketch, Europa has just completed an annular transit of Ganymede, passing in front of the larger moon but not blocking it completely. Because of Jupiter’s low altitude, I was unable to use high enough magnification to see any detail of the transit beyond watching the two bright dots move towards each other, merge, and then move apart.

At the same time, Callisto (the largest Galilean moon) was transiting in front of Jupiter. Unlike the two smaller moons, Io and Europa, which tend to disappear from view after they cross the Jovian limb, Callisto (and Ganymede) usually can be seen against the cloudtops due to their darker albedo. [All of the moons’ shadows can be seen in transit given adequate seeing conditions.]

This sketch of Jupiter was done at the eyepiece using 2B and 4B graphite pencils on white copy paper. After scanning, I set Jupiter against a black digital background, placed the positions of the satellites from field notes, and added the text.

I hope you enjoy this view of the King and his consorts and get a chance to see one of these transits yourself before the giant planet disappears for the year.

Jupiter and Galilean Moons
Planet
Friars Hill, WV USA
17 November 2009

Clear skies,

Michael Rosolina

Shadow of Ganymede

Jupiter with Ganymedes’ shadow and moons Europa, Ganymede, Io, Callisto
Sketch and Details by Peter Mayhew

* Object Name: Jupiter with Ganymede’s shadow: moons left to right
are Europa, Ganymede, Io, Callisto
* Object Type: Planet, moons
* Location: York, UK
* Date: 24th September 2009, 20:00 UT

I made a graphite pencil sketch on a white paper template at the
eyepiece, and also noted colours then. Later I scanned this and used
editing software to make the image a negative and then added colour.
The view was as seen through my Skywatcher Skyliner-150mm Dobsonian (f8)
with a 10mm eyepiece, giving x120 magnification and 26′ field of view.

The seeing was pretty wobbly at first but settled. Over about an hour
the shadow of Ganymede traversed from right of centre to left of centre.
I felt very lucky to see this as there was 100% cloud at 19:00 UT and
cloud obscured the view again at 22:00 UT, meaning that clear skies were
only present during the shadow transit. I was surprised at how visible
the shadow was, even at low power with a 25mm eyepiece.

Peter Mayhew

Jupiter and Moons Do a Double Take

Jupiter and transiting moons, Ganymede and Europa
Sketch and Details by Serge Vieillard

Serge made these remarkable Jupiter sketches on the evening of August 19, 2009 while attending an Astronomical meeting in Valdrôme, France. He was using a 600mm scope and was sketching Jupiter and its moons and shadows as they crossed in front of the planet. The larger moon and shadow is Ganymède and the smaller one is Europa.

Jupiter and transiting moons, Ganymede and Europa
Sketch and Details by Serge Vieillard

Serge’s remarks roughly translated are, “Then, Ganymède leaves the planet, Europe having about the same luminosity that the planet has, disappears between the two shadows which are oval in appearance due to perspective. The effect of relief is seizing, one feels the 3D, and the height of the satellites compared to Jupiter which are accentuated by the presence of shadows. Then Europe appears and cuts out in the darkest zones of the limb. It bites the shadow of Ganymède for it is its turn to leave the disc of Jupiter. At this time, the relief is total”.