Saturday, February 10, 2007

Saturn in Opposition

Today, at 18:42:05 UTC, to be precise, planet Saturn is in opposition. This means that as seen from Earth, Saturn and the Sun are at opposite points on the celestial sphere, as is the Moon at Full Moon. So, Saturn is visible in the sky all night long, reaching the highest point of its path around midnight. Since the orbits of Earth and Saturn around the Sun are nearly circular, opposition also means the closest approach between Earth and Saturn. Today, the distance to Saturn is roughly 8.20 Astronomical Units, or 8.2 the distance from the Earth to the Sun. Thus, Saturn is also brighter right now than at any other phase of its orbit.

Planet Saturn in November 2006 as seen from Earth.
(Credits: Jeff Barton and Josh Walawender, via JPL/SOC).

In fact, if you look at the Eastern sky two or three hours after sunset, it's very easy to spot Saturn: Follow the line from the right hand stars of Ursa Major, the Big Dipper, away from Polaris to the head of Leo, the Lion: There is Saturn, the brightest light in this region of the sky, outshining even Regulus. Technically speaking, Saturn's magnitude is 0.0 today.

View toward the Eastern horizon from 49°36' North 7°East, on Saturday, February 10, 200, at 20:30 UTC (Credits: Saturn is the brightest object in this region of the sky.

Opposition is the best time to observe the outer Planets, and even with a very small telescope, the rings of Saturn make an impressive view. I remember well the feeling of surprise and awe when I first spotted them through my Kosmos 68 mm refractor. Of course, there are now the breathtaking photos from the Cassini/Huygens mission, but to see the planet and its rings with your own eyes is something different again.

The NASA/JPL in Pasadena has used the current opposition of Saturn to launch the public outreach "Saturn Observation Campaign", where observatories and associations of amateur astronomers all over the world offer public talks and opportunities to have a glimpse at Saturn through real telescopes. The idea is to convey the fascination for astronomy and the science and facts behind the beautiful pictures from Cassini. Check out the list of events - maybe there is also something nearby to your place?

The Peterberg Observatory (Credits: Sternwarte Peterberg)

Yesterday night, I went to the "Night of Saturn" at the Sternwarte Peterberg - that's a small observatory run by the Association of Amateur Astronomers in Saarland, next to the place where my mother comes from. An uncle of mine still lives there. He is a member of the Association and gave me a private tour of the observatory and its instruments while one of the talks was running.

The main telescope in the dome of the Peterberg Observatory.

Unfortunately, weather yesterday night was quite typical for February in Germany - it was overcast. There had been some open spots between the clouds early on, and I could see the bright light of Saturn in the sky for an instant. But when the dome of the large telescope was supposed to be opened, even a slight drizzle had set in. So, we had to be content with a great presentation of stunning Cassini photos instead...

But here is the good thing about oppositions: It's not a big deal if you miss the date. Observing opportunities will be equally good over the weeks to come, and so I hope I will have more luck spotting Saturn soon again...

Clear Skies, as they say :-)

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a quantum diaries survivor said...

Sure, Stefan, try again soon. Saturn is delicious this year. First of all, the opposition happens with quite favorable conditions for northern observers, since the planet is high between Cancer and Leo. And second, the angle of the rings is one of my favorites: not too small, and not too wide. Several shadows and small details are apparent at this tilt.

I have had the same experience as you, the first time I aimed at Saturn with a mere 40mm refractor: awesome. I think it is a very good idea to show saturn to novices, it is by far the sight that thrills the most the casual observer.

Maybe I will venture to offer an observing session from Venice in the Nasa site. I see private citizens doing it, why not me ? I own a 16" dobsonian and Saturn through it is definitely awesome.


Paolo Amoroso said...

Here is how the Earth looked like as seen from Saturn at the time of opposition. Courtesy of JPL's Solar System Simulator.

stefan said...

Hi Paolo,

mille grazie for the link to this JPL site - that's great!

Hi Tommaso,

yes, I'll try again - and especially on March 2, when for those of us living in Central Europe, there will be an occultation of Saturn by the Moon :-)...

I think it is a very good idea to show saturn to novices, it is by far the sight that thrills the most the casual observer.

That's also my experience! The thing is, in my opinion most deep sky objects are quite disappointing to look at with the eye through a modest telescope (not one like your dobson ;-), I somehow had missed your Encke division post...) because you just see grey blobs, and never the beautiful colours one is used to from all the modern photos.

Ciao, stefan

Rae Ann said...

Very interesting! We bought a kind of nice telescope a couple of years ago, but I've forgotten how to set it up. It's a home-made "Dobsonian" with an 11 inch mirror.

Rae Ann said...

Sorry that link got cut off.

webmaster said...

Hi, Stefan!
Nice post about your visit at our little observatory :-) Hope you enjoyed it!
I actually found your blog while discovering the features of technorati a few minutes ago (just type "Sternwarte Peterberg" and so on ...).

Cheers and clear skies!
Peterberg's Webmaster

stefan said...

Dear Peterberg Webmaster,

now, that's a suprise! Yes, it was nice to be there, despite the rain, and I for sure will come again. It's in the neighbourhood anyway!

BTW, I hope you don't mind I've borrowed the photo, and also the beautiful one with the aurora :-)

Cheers, stefan