Sidewalk Astronomy: Saturday, October 20, 7pm - ?

Other Keywords:  Rosemead San Gabriel Pasadena El Monte Temple City Arcadia Area Public Telescope Viewing

[Edited 3 October]

Sidewalk astronomy in Monrovia (northwest corner of Myrtle and Lime, which is in Library Square Park) is scheduled for Saturday, October 20, 2007, from dusk until 9 or 10pm.  How late we stay depends in part on how many people are stopping by for a peek.

This month, Jupiter is closing towards the sun.  It's several  hundred million  miles further away now than it was about six months ago.  So it'll be smaller and there'll be less detail to be seen.  On the other hand, we should have a clear view of the moon.

Other objects may also be viewed, depending on how clear the sky is and if I remember to bring the right combination of mounts and hand controllers.


This week's observing is in conjuction with a 24-hour cancer fundraising event.  This will probably mean a larger crowd, which may require you to park a little further away.  But there's lots of free parking around Monrovia's Old Town, so you shouldn't have any trouble finding a space.  It'll be a bigger deal for us telescope folks, who may need to lug our equipment a little further than we'd like!


International Sidewalk Astronomy Day is Saturday, May 19, 2007.  Saturn and the moon are still the main attractions, with Venus visible until around 9pm or so from our observing location.  As always, the telescopes are free to view through and will be stationed near the northwest corner of Myrtle and Lime in Monrovia.

I'm pretty sure Jupiter is still rising too early for Sidewalk Astronomy viewing in May.  By our June and July sidewalk dates, however, it should be climbing above the buildings of Old Town early enough for sidewalk viewing.

The Sky in June

Look high to the east as the sun sets.  The first "star" you see, about half way up in the sky, is the planet Venus.  Venus is just a bit smaller in diameter than Earth, and just a bit closer to the sun.  But it's atmosphere is 98 percent carbon dioxide.  Clouds shroud the planet, but because of the CO-2 content, the planet's surface is somewhere in the neighborhood of 800 degrees F.  Just thought I'd mention that.


Can't say for sure when the next sidewalk astronomy event will be.  A likely date is June 23, but that's not a firm date.

Next Sidewalk Date: June 23, 2007

The June 23 date in Monrovia is now firm (weather permitting, of course). 
Jupiter is rising earlier and earlier.  It should clear the buildings around Myrtle and Lime by 9pm on the 23rd. For those of you not at Myrtle and Lime, look to the southeast an hour or so after sunset. Jupiter will be the bright object you see in that direction

Venus is still high at sunset and won't disappear below the trees until 10 pm or so.
Saturn is still a bit higher than Venus at sunset, but not nearly as bright and obvious.  But if you find Venus then move to the southeast (up and to the left), the next bright 'star" you run into will probably be Saturn.

Just a bit further to the northeast and you'll run into Regulus, the heart of the constellation Leo.

Factoid of the post: Jupiter and Saturn are "gas giants," composed almost entirely of hydrogen and helium. There's no solid surface to stand on, although if you drop far enough into its atmosphere, you'd probably eventually run into a sea of liquified hydrogen and helium. Of course, you'd suffocate long before you reached that sea. And if you didn't, the pressure would crush you to death. So it's probably a good thing that you don't live there. ;-)
Factoid number two: Jupiter's "day" is only about eight hours long. Saturn's day is about ten hours long. Because both planets are rotating so fast, their appearance is distinctly oval, not round. (The earth is also slightly squished due to its rotation. But because we're small and rocky, and because our day is much longer than theirs, Earth appears much more nearly like a marble and not like a squished balloon).

Planet = Wanderer

The word, "planet" comes from a Greek word meaning, "wanderer."  Because, unlike stars, which maintain their positions relative to each other for years at a time, the relative motion of planets can be easily discerned.  For example, find Venus, Saturn and Regulus.  Today (June 15), the three objects are pretty much all lined up, with Saturn in the middle, Venus down and to the right, and Regulus up and to the left.

Tonight, you can hold your outstretched fist at arms length and it will roughly span the distance between the planets.  Over the next two weeks, watch as Venus and Saturn appear to move closer together.  By the end of the month, they'll be separated by only about a thumb's width.

Lights Out L.A.

This made the front page of the SGV Tribune:

We'd have been out on the sidewalk in Monrovia regardless, but we'll be sure to say a few things about Lights Out L.A. if anyone asks.