Tuesday, April 28, 2009

Moon and Pleiades

I collect Moon and Pleiades shots. At least once a year, the Moon and Pleiades align for a close-up at a reasonable hour. This one, taken 26 Apr 09, clearly challenged my telescope's field of view.

The photo was taken with a digital camera. Had I felt like loading film, I would have been able to include more space outside the moon and Pleiades. Below is another photo. Same camera but with a telephoto lens:


Friday, April 24, 2009

Earth, Orbit, and Climate

I'm spoofing myself with the above illustration. On 4/23, I had the pleasure of showing my illustrated and animated presentation, Earth, Orbit and Climate to a local middle school . The presentation loosely follows the first chapter of Ray Pierrehumbert's book, Principles of Planetary Climate, but also illustrates radiative balance as described in Trenberth et al.'s Earth's Global Energy Budgets. In addition to these main courses, the presentation also compares and contrasts atmospheric CO2 to water vapor, and ends with my attempts to understand how orbital forcing plus changes in the carbon cycle create and destroy ice sheets. The presentation celebrates the various scientific disciplines that reveal the global warming story, and doesn't call for specific action, but in clarifying the behaviour of CO2, I'm supporting the call for changes in our energy production and other activities that contribute to global warming.

About ten minutes before the presentation, our region suffered a power outage. The irony wasn't lost on me.

Power was restored shortly after, and I presented to two groups.

Wednesday, April 22, 2009

Blocking my View of Venus

I've been assured by the Justice Department that holding a crouching position for the time needed to capture this series of images did not induce any long term physical damage or emotional distress. My legs are still tired from my sustained crouch, but it was worth it. The mosaic above shows the moon occulting Venus from about 5:08 - 5:10 am on 4/22 (as viewed from Southern California).

All photos were taken with a Canon Digital Rebel, 200 ISO and shutter speed of 1/160 shutter speed. Lens used was a 3-inch APO refractor with focal reducer, producing a focal ration of ~F5.


Monday, April 20, 2009

Dark skies and CO2

A friend from the International Darksky Association just sent me the following, which I'm posting verbatum:

Many of you may already know that on Friday, April 17th, EPA declared CO2 to be hazardous.

This finding will require a 60 day public comment period.
(Instructions for submitting a Public Comment, see http://epa.gov/climatechange/endangerment/downloads/Instructions-comments.pdf)

Since outdoor lighting uses energy, and since energy generation, in most cases, results in C02 emission, a very strong case can be made to reduce wasteful levels of outdoor lighting. Each 100 watt dusk-to-dawn streetlight requires the generation of electricity that will result in 500 lbs of CO2 emission per year. With an estimated 50 million streetlights, that's 12.5 million tons of CO2 emissions...

Some significant areas of opportunity that the EPA could cover might include EPA regulations:
1) limiting streetlight use to only hours when necessary (Programmable photocells, Photons on Demand)
2) removing streetlights from service where streetlights are nonessential for public safety
3) mandating the use of motion sensors for all outdoor and indoor lighting.
4) requiring utility regulators to include rates for midnight shutoff streetlights
5) requiring utility regulators to include rates for lowest energy consuming lamps commonly available in the market for street and area lighting
6) setting light trespass standards to reduce energy waste.

What it takes: A coordinated effort to influence EPA on the carbon footprint resulting from outdoor lighting, and the significant reductions in greenhouse gas emissions that can be attained by adopting regulations to control light pollution.

Who needs to make a public comment to EPA on the need to regulate outdoor lighting?:
Federal agencies and regional offices (EPA Boston, National Park Service)State legislators
Members of Congress
State agency administrators
Municipal administrators
Dark sky advocates

This EPA public comment period could be the most significant opportunity so far to raise the light pollution issues at the federal level.

Please consider submitting a comment to EPA advocating the regulation of street and area lighting, both in commercial and residential applications, and circulating this email to others who might have an interest in submitting a comment of their own...

Thursday, April 2, 2009

Archeo-astronomy, cupula rock

Archeoastronomy is the science of using what we know about astronomy, specifically naked-eye observations, to infer meaning in archeological artifacts. My knowledge of this subject comes mostly from Ray Williamson's book, Living the Sky, and from an inlaw who's contribution is cited within Williamson's book. Living the Sky also mentions constellations in great basin petroglyphs, and a possible example from the Temecula Valley is shown here:

Native americans left at least two records on local rocks: 1) grinding holes used in the preparation of food, and 2) smaller holes such as those you see in the rock above. These holes are about the size of a golf ball split in half, possibly ground with a rock of this size. When the sun is overhead shadows are cast, making the holes look like dark stars on pale rock.

A group of stars in the middle bears a strong resemblance to the constellation Cassiopeia, with one qualification: The hole at the apex of the 90-degree angle in Cassiopea is not like the others; it appears to be natural, suggesting either that the carver exploited a natural nook (quite understandable if you've ever tried to drill rock or scrape out a fossil) or that the excellent match to Cassiopea is a coincidence.
These cupulas can be found throughout the desert of Southern California. Below is an example from Anza-Borrego Desert State Park. Though I can imagine several constellations in the rock shown above, I can't claim to see any in the one below.

In this post, I tried to model the type of language and caveats offered in the primary science literature. Any claim (e.g., in this case, that the holes could be constellations) is offered with any known evidence that would undermine certainty in this conclusion (e.g., not all of the holes in Cassiopea were necessarily drilled by human hands). And so it was when I read an paper in Nature (in 2000?) that claimed the first observational evidence of the greenhouse effect. The authors did not declare themselves right and sceptics wrong. They merely stated something like "should our observations be corroborrated by further research...." They also cited concerns over the field of view and resolution of the instruments used in their analysis. This willingness to expose strengths and weaknesses in our observations and beliefs is a characteristic of good science, and is an attribute we can look for in determining whether we are reading science or propoganda.