Friday, February 27, 2009

Venus and Crescent Moon Conjunction

In my post on seeing Venus during daylight, I mentioned that today would be a great day to try since Venus would be very near the moon. Sadly, here in Mesquite it is completely overcast today so I'll miss the event. If you live west of the North Texas area and it isn't cloudy where you are, step outside now to see whether you can spot it. Venus will be about a half-dozen moon-widths from the moon opposite its sunlit crescent side.

Even if you miss spotting Venus during daylight today, be sure to step outside in the evening to check out the beautiful pairing as it gets dark. It's already dark in the U.K. and folks like Nick Bramhall have already starting capturing this stunning sight. Read more about it at NASA Science site.

Monday, February 23, 2009

Comet Lulin at Closest Approach

Step outside this evening and look up high in the southeastern sky for a bright yellow star. That's Saturn. Just to the right and above it, you'll see a small, fuzzy patch of green. That's Comet Lulin (C/2007 N3). It is now at its closest approach to Earth, speeding by on its way out of the Solar System.  Although it's at its peak brightness and appears closest to Saturn tonight, it will still be visible for a while so if you miss the show tonight so you still have time to catch it.

If you live in an urban area, you might have a tough time spotting Lulin. To get a really good view of it, especially under light polluted skies, you need binoculars or a telescope. If you don't have a that kind of equipment or it's cloudy where you live you can still see live images over the web.

To start with, check out the Comet Lulin webcast at the Coca-Cola Space Science Center at Columbus State University. They have live webcam images that updated every 15 seconds throughout tonight.

If you want to see Lulin (whether tonight or in the coming weeks) and you think you might enjoy remote access to professional telescopes at an affordable price, go check out Slooh. They have a site in the Canary Islands, one in Chile and another one under construction in Australia. You can purchase 100 minutes of viewing for $14.95 or just check things out (including the ability to control the telescopes) with their 7 day free trial. And tonight they are highlighting Comet Lulin; see the mission schedule here

Since we've got poor seeing tonight, my plans to get out with my camera and telescope fell through so I've spent the evening following the comet at Slooh. Here's a shot I saved a while ago.

Hopefully, we'll have clear skies in the next couple of days so I can get some shots with my own equipment but, in the mean time, it's great to have access to someone else's gear.

For more information on Comet Lulin, check out these sites:

Friday, February 20, 2009

Spotting Venus in Daylight

I've been planning a post on how bright Venus has been in the evening sky lately, but it's turned into more of a research effort than I expected. I still plan on posting about that eventually but in the meantime let's talk about a side effect of how bright Venus is.

At its brightest, Venus is normally1 the third brightest object in the sky behind the Moon and the Sun. We don't typically see celestial objects during the day other than the Sun and, depending on its phase, the Moon. The reason has to do with contrast - the difference in brightness between two objects. To see an object in the sky, it has to be brighter than the background. That's why you can see stars at night but not during the day: the scattering of sunlight in the atmosphere makes the sky too bright compared to the stars. This is also why you can't see the Milky Way in urban areas. Light pollution increases the brightness of the sky, reducing the contrast between the Milky Way and the background sky until there isn't enough difference for the Milky Way to stand out.

So, if you can't see stars during the day then is it possible to see Venus? As bright as it gets (apparent magnitude -4.7), it is still not nearly as bright as the Moon (-12.6). As it turns out though, it is bright enough to see in broad daylight. You just have to know where to look.

As bright as Venus is right now and given how far it is above the Sun (its elongation), now is a great time to try spotting it during the day. To find it, it helps to have something else nearby to start your search from. A good candidate is the Moon. I checked using one of my favorite pieces of software (Planetarium) and found that over North Texas the Moon and Venus will be just a few degrees apart about 2:30 p.m. on February 27th. Although the Moon will be a thin crescent on that date, it should still be a good starting point for finding Venus. I plan to try this approach on the 27th but in the meanwhile there is another alternative that you can try tomorrow. 

First, find a building with an exterior wall that runs generally north and south. The next step is to know what time during the day Venus will be directly over head (it's transit time). To find that for your location, use this tool hosted by the U.S. Naval Observatory. Scroll down to Form A, enter the date, Venus as the object, your state and city and optionally your elevation above sea level, then click on the Compute button. The resulting data includes the time Venus rises and sets but more importantly its transit time and how high in degrees above the southern horizon it will be at that time (its altitude). 

With this information in hand, grab a pair of binoculars and stand next to your north/south wall shortly before the specified transit time. It needs to be a wall facing east so that as you stand next to it you're in shade (or, if viewing when Venus is in the morning skies, use a wall facing west as Venus would transit before the sun). This will avoid glare from the Sun as you search for Venus and also guard against accidentally looking at the Sun through the binoculars. Standing next to the building, search the sky just along the edge of the roof of the building, scanning back and forth at approximately the angle Venus should be above the southern horizon. 

I tried this yesterday and it worked great. Venus was to be straight overhead at 2:57 pm at an altitude of 67 degrees. Our house faces due south so all I had to do was step outside on my patio and stand next to the east-facing wall.  By scanning the sky along the edge of the roof overhead I was able to spot Venus easily through my Canon 8x25 binoculars (you don't need big, powerful binoculars - almost any decent pair will do). I got a great view of a crescent Venus. 

For something a little harder, once you've spotted Venus through binoculars try searching that same spot without them. It takes a bit more effort but once you know where to look and what you are looking for it is possible to spot it with the unaided eye. 

I'll post an update the next time I've spotted Venus during the day and include a photograph. In the meantime, once you've succeeded in spotting Venus in the daytime yourself, share the wealth and show it to your friends, family or neighbors. I bet they'll be amazed!

1 According to this Wikipedia article, objects (past and present) brighter than Venus include the Crab supernova of 1054 and Iridium satellite flares.

Wednesday, February 18, 2009

Geek's Night Out

Man, it was hard to get up this morning. Didn't even budge when the dog jumped on the bed around sunrise. Understandable after not getting to sleep until about 1:30. No, I wasn't up late out under the stars with the telescope. Last night was more like the last time I went to a rock concert...
  • I quit work early
  • Linda and I had an early dinner and drove all the way across town
  • Showed up an hour and a half before the doors opened to be sure we got good seats
  • Sat in rapt attention throughout a show that was supposed to last about 2 hours but went on for over 3 hours
  • Stood in line afterwards for 45 minutes to get an autograph
  • Didn't get home until well after midnight
...but this wasn't a rock concert. It was all to see an astrophysicist!

As mentioned in my last post, we'd heard last week that Dr. Neil deGrasse Tyson was scheduled to speak at University of Texas at Arlington last night. Thankfully, we also got a reminder email that mentioned they expected a large turnout. It was good we got there early as, by the time Dr. Tyson took the stage, Texas Hall was completely packed, all 2700 some odd seats. Although the long wait could have been boring, we ran into RCYC friends - Burt and Mary Scott - and had a great time visiting. Burt teaches Astronomy at Eastfield College and is also an avid amateur astronomer - I enjoyed hearing about the new telescope he is building while we waited for the show to start.

If you've ever seen Dr. Tyson on PBS, the Tonight Show, the Daily Show or any of his other appearances on TV, you understand what a dynamic speaker he is. And while many people know him as one of the most vocal advocates for the idea that Pluto is not the 9th planet but instead the first Kuiper Belt object discovered, that wasn't what he was in town to talk about. Instead, he was here to talk about science illiteracy in America and to explain his ideas on what to do about it.

Before getting down to business, Dr. Tyson first got comfortable, unloading his pockets of wallet and cell phone and even shedding his cowboy boots. Although he was born and raised in New York, he spent 6 years working on a Masters Degree at University of Texas in Austin and obviously picked up on our local fashion sense and attitudes towards casual attire.

Dr. Tyson then illustrated and described the history of commitment to science by various countries and cultures, starting with a series of diagrams based on the Periodic Table of Elements. This wasn't anything like the PTE you dreaded in high school - it was more of a map and timeline, showing things like which countries discovered (and named) each element, when they were discovered, etc. In the end, the picture he painted was that until recently the U.S. has been a dominent force in scientific discovery but that the new trend is diminishing emphasis on (and investment in) science. He then went on to cover numerous examples of our cultural scientific ignorance including our fear of the number 13 (most buildings still don't have a 13th floor) and celebration of Groundhog Day (when you didn't have advanced computer models to tell you what to expect of the weather, you might as well let a ground hog decide but why do we still bother?).

There were two other key points from Dr. Tyson's presentation. First, that significant investment in science most frequently stems from war or, in the past, colonial expansion. Examples include the influence the Cold War had on the Space Race between the U.S. and Russia and the failure to fund completion of the Super Conducting Super Collider as the Cold War ended. Second, that there is no better way to ensure economic growth and prosperity than through scientific innovation. The bottom line? It's that our future depends on changing the trend, finding ways to increase interest in science education, bring about cultural change such that we celebrate and embrace science and scientific advancement rather than shun it, and to stimulate investment in scientific research. Preferably without another war.

Many of the ideas he proposed centered on NASA. In speaking on NASA's role in American science, he suggested that instead of continuing to invest resources in "going where hundreds have gone before" - sending men into low earth orbit - NASA should leave that to commercial companies and go back to pushing the boundaries of space exploration, pursuing lofty goals such as sending men to Mars or mining asteroids for natural resources. Besides facilitating accomplishments for which there is not yet a viable business model, NASA would be continuing its historical role of achieving the seemingly impossible and, in doing so, inspire new generations of scientists. Of course, that sort of thing isn't cheap but Dr. Tyson stressed how little it would take citing that NASA's entire budget is currently only 6 tenths of a cent out of every tax dollar. Imagine what they could do if we spent just another 6 tenths of a cent per tax dollar to double NASA's budget...

Dr. Tyson ended his talk with a mathmatical progression, starting with 1 and ending with one quadrillion, using each step to relate the number to something concrete such as the number of grains of sand on a beach (having fun with dimmed lights and the number Sextillion along the way). While some people look at images such as the densely packed starfield projected behind Dr. Tyson to illustrate septillion (the number of stars in the observable universe) and feel small, he said that he prefers to look at it in a different way. Knowing that we are made of the same elements as the cosmos and that, in spite of how little we understand about the universe, the human mind was capable of building the Hubble Space Telescope and discovering just how vast the universe is gives him a feeling of connection to the cosmos and an appreciation of its majesty.

After his presentation Dr. Tyson conducted an extended Q&A session, finally wrapping up over 3 hours after he started. It's late now (need to catch up on the sleep I didn't get last night) so I won't get into details on his responses other than to highlight one of the last and most amusing. A 10 year old boy stepped up to the microphone to ask what Dr. Tyson would do with a black hole if he could control one. After asking why the boy was up so late (answer: he's home schooled and was there on a field trip with his parents), he explained how hard it would be to control a black hole but that, if you could, what a great trash dump it would make!

By the way, if there is any question of who the Geek is in the title of this post, who do you think surprised Dr. Tyson by bringing an article on the Pluto debate from the December issue of Sky and Telescope for him to sign? I guess that makes me almost as big a geek as the guy who brought in a telescope eyepiece for him to sign.

Another great way to celebrate IYA2009!

Related links
UTA article on Dr. Tyson's apperance
News video on WB 33 TV
Interview on KERA program Think
The Pluto Files

Friday, February 13, 2009

Opportunity to Meet a Star

For those of you in the Dallas / Ft Worth area, you have an opportunity to hear Dr. Neil deGrasse Tyson, noted astrophysicist, author and director of the Hayden Planetarium in New York, speak at the University of Texas at Arlington on February 17th. Probably best known for his appearances on numerous PBS science programs and for his position on the status of Pluto as a planet (that it isn't one), Dr. Tyson is a visible and vocal advocate for science, astrophysics and space exploration. His appearance at UTA as part of the Maverick Speakers Series is open to the public and attendence is free. For more information and tickets, see:

Maverick Speakers Series - The University of Texas at Arlington