Bakersfield Night Sky – September 19, 2015
By Nick Strobel
The sunsets are noticeably earlier than just a few weeks ago and as you are driving on east-west roads to and from work, you'll notice that the Sun is more likely right in front of you or blinding you in your rear view mirror. The autumnal equinox is on September 23rd. This is when the Sun will be on the celestial equator so it will be directly over the Earth's equator. Therefore, the Sun will rise due east and set due west on that day. During the rest of the days of fall, the Sun will be moving southward and the amount of daylight will continue to decrease. Because the Sun's position with respect to the Celestial Equator sets the time of the equinox, I can tell you that the season of fall begins precisely at 1:21 AM Pacific Time September 23rd for the year 2015. Astronomers do love their numbers.
I do hope and pray (yes, even some astronomers do that) that with the Sun moving southward and shorter daylight, that we'll get a break from high temperatures. There is talk about El Nino coming this fall but we need the right kind of El Nino to give us some relief from the drought. We need an especially strong El Nino that brings cool temperatures and moisture to northern California, so that the precipitation comes down as snow and stays that way in our water bank up in the Sierras. If that doesn't happen, we'll be in a world of hurt next summer, even if we get rain here this fall and winter. That rain water will run off mostly back into the oceans because our dams aren't large enough to hold all the run off we need for next summer. Our largest water storage place is the Sierra snowpack, so keep a close eye on what happens to the Sierras during this El Nino.
Next Sunday evening, September 27th will be a total lunar eclipse. It couldn't be timed any better for us---in the evening after sunset. When the Moon rises for us, it will already be partially in the Earth's umbra (the darkest part of the Earth's shadow). Totality begins at 7:11 PM and the Moon may be just above the mountains in the east by then, depending on how close you are to them. Totality lasts until 8:23 PM when the Moon will be about 20 degrees above the eastern horizon, or about the width of your outstretched fingers held at arm's length. See the attached star chart. The partial eclipse will end at 9:27 PM when the Moon is about halfway up in the southeastern sky. The Kern Astronomical Society will be moving the date of its monthly free public star party at Panorama Bluff Park to Sunday, September 27th because of the total lunar eclipse.
Depending on the dustiness of the air worldwide, the color of the eclipsed Moon will be either a dark brown to coppery yellow or something in between. Sunlight passing through the Earth's atmosphere refracts, or bends, around the solid part of the Earth, so some light still reaches the Moon. The shorter wavelength bluer colors in the sunlight are scattered away, so they don't reach the Moon during the eclipse.
This lunar eclipse has the added feature of happening at the closest full moon of the year, a so-called "supermoon". Next Sunday's full moon will appear about 13% larger in diameter than what we saw in April's very brief lunar eclipse. Have an early dinner and come join KAS for a great show on the bluffs. Everything's free!
Oh, and don't worry about any of the wild and crazy hoaxes being passed around the net about some asteroid or comet hitting Earth later this month. In early August I received an email from someone visiting South Africa wondering about what would happen if an asteroid of a size and speed that I don't recall now hit her home in Puerto Rico. What size of tsunami would they experience in South Africa where she was staying from such an impact.
I have the equations on a page in my Astronomy Notes website called "Effects of an Asteroid Impact on Earth". I ran through the numbers and gave her an estimate with the usual caveats that the height also depended on how the tsunami's energy was dissipated from the passing around the shorelines of the continents between Puerto Rico and South Africa.
Only now do I find out that yet another doomsday asteroid story has been circulating around the internet for over a month now. Why am I the last person to find out about these doomsday asteroids, comets, stars, black holes, etc.? My internet experience is so boring in comparison, since I stick to legitimate websites of credible journalism and peer-reviewed science sites. I need to get out into the world WILD web and get some excitement in my life!
Now dialing back the sarcasm, let's take a look at what's happening in tonight's sky. Saturn is the only naked eye planet visible in the evening sky. Saturn will be the bright "star" to the right of Scorpius in the southwest at the time the sky is truly dark. Saturn will be at the same altitude above the southwest horizon as orange-red heart of Scorpius, Antares, with Antares on the left and yellowish Saturn on the right. Mercury was briefly visible in the first part of the month but now its gone.
Neptune and Uranus are up in the evening sky but you're going to need a telescope or good pair of binoculars to pick them out. Neptune is in Aquarius and Uranus is in Pisces (see the first star chart below). Those with super-sharp eyes and very dark skies might be able to pick out Uranus without binoculars about a fist-and-a-half at arm's length to the left of the Moon during the lunar eclipse but my eyes are on the poorer side of the bell curve, so binoculars it will be for me.
By 9 PM, Cygnus, the Swan, will be right overhead with Deneb at its tail. Deneb is one point of the Summer Triangle made of Vega, high up in the southwest, and Altair, lower in the south at the other two points of the triangle.
In the early morning sky Venus will be as bright as it can be (see the second chart below). Venus will rise about 4 am and be a quarter of the way up in the eastern sky by 30 minutes before sunrise. Jupiter will now be joining Venus in the early morning sky. Jupiter is about a fist width at arm's length above a perfectly flat horizon by 30 minutes before sunrise below the middle of Leo. About halfway between Venus and Jupiter will be dimmer orange-red Mars. Watch Mars over the next several mornings close in on the bright star of Leo, Regulus. In the middle of the week on the 24th and 25th, Mars will be close enough to Regulus that your thumb at arm's length will easily cover them both. The orange-red color of Mars will be accentuated as you compare it to blue-white Regulus.
Want to see more of the stars at night and save energy? Shield your lights so that the light only goes down toward the ground. See www.darksky.org for how.
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com