Category: Astronomy

Exploring the cosmos

Shift a Little Weight

The trade-winds have returned for the evening. And while they are welcome for the comfortable temperatures they bring, the winds are unwelcome for the problems they create at the telescope. I am trying to get in one last exposure sequence for the evening, but the guider graph shows trouble. There are constant errors, not small errors either. The Right Ascension axis seems to be the issue, with errors of +/-3 pixels on the guider. This is just not going to work.

I watch the graph for a while, trying to figure out what I can do. I have had an issue where the guide star was the source of the problem, two stars to close together, a double star I did not notice when selecting my guide star. I stop the guider and select another star… The problem continues.

As I feared, my problem is most likely the wind this evening, a continual issue on this rock I live on. A speck in the middle of a very large ocean, the winds are a fact of life here. I only shoot with small telescopes, less sail area to catch the wind with a short tube. A TeleVue 76mm, an AT6RC, or simply a wide angle camera lens. The smaller scopes provide less loading for the old Losmandy G11 I mount them on.

I decide to try something else, shifting the balance to load the RA gear down. I gently slide the counterweight down the shaft about an inch. There is barely a blip on the guider as I make the adjustment. Better yet the guide error graph settles down! Looks like I will be able to get in a few more exposures before putting the ‘scope away.

Guider Error Graph
The guide error graph showing the effect of shifting a counterweight.

Postcard from the Universe – Comet C/2012 K5 (LINEAR)

Another product of imaging earlier this week. Comet C/2012 K5 (LINEAR) is fading, but still bright enough to image. Right beside Orion it was well placed to target from my driveway. Just refreshing my comet hunting skills, getting ready for the show over the next few months as C/2011 L4 (PanSTARRS) comes into view.

C/2012 K5 LINEAR
C/2012 K5 LINEAR with AT6RC and Canon 20Da, stack of 18x6min

Postcard from the Universe – NGC1365 and Supernova 2012fr

A photo taken from my driveway of NGC1365 and supernova 2012fr. It is a bright supernova in a classic barred spiral galaxy. I had observed NGC1365 in mid-October with the 18″, noting the beautiful spiral structure. The supernova appeared about two weeks later. I have since observed it in a couple telescopes, including Cliff’s 24″.

The nova seems to be fading now, it peaked around 12th magnitude in November. Currently about 14.5 magnitude, but still easy with the AT6RC and Canon 20Da camera.

NGC1365 and SN2012fr
The barred spiral galaxy NGC1365 and SN2012fr

Black Holes and the Fate of the Universe

This is a recoding of a Keck Observatory Astronomy Talk given by Dr. Günter Hasinger, Astronomer and Director of the University of Hawaii Institute for Astronomy. His talk, ‘Black Holes ad the Fate of the Universe’, was given on November 20, 2012 at the Gates Performing Arts Center at Hawaii Preparatory Academy, part of the W. M. Keck Observatory public lecture series.

It’s a little bit of the story of the Universe from beginning to end,” said Dr. Hasinger. “What role do black holes have on the fate of the universe, what are they, and how we can understand them better?”

Günter Hasinger from Keck Observatory on Vimeo.

Surprise: Earth-sized Planets Are Common

W. M. Keck Observatory press release…

A team of astronomers from the University of California, Berkeley and the University of Hawaii at Manoa has found that 17 percent of all sun-like stars have planets one to two times the diameter of Earth in close orbits. The finding, based on an analysis of the first three years of data from NASA’s Kepler mission and the W. W. Keck Observatory on the summit of Mauna Kea, Hawaii, was announced at the American Astronomical Society meeting in Long Beach, California this week.

While other studies had shown that planets around stars are common in our galaxy, until this study, it remained unclear if this is true for Earth-size planets.

Exoplanet Census
The fraction of sun-like stars having planets of different sizes, orbiting within one-fourth of the Earth-sun distance (0.25 AU) of the host star. Image credit: Erik Petigura, Geoff Marcy, Andrew Howard,
The team consists of UC Berkeley graduate student Erik Petigura, former UC Berkeley postdoctoral fellow Andrew Howard, now on the faculty of the UH Manoa Institute for Astronomy, and UC Berkeley professor Geoff Marcy.

To find planets, the Kepler space telescope repeatedly images 150,000 stars in a small region of the sky. It looks for a tiny dip in each star’s brightness that indicates a planet is passing in front of it, much like Venus passed between Earth and the sun last summer.

We took a census of the planets detected by the Kepler Space Telescope,” said Howard. “Erik Petigura wrote a new pipeline to detect the shallow dimmings of Earth-size planets in Kepler photometry. With his efficient and well-calibrated pipeline we could confidently report the size distribution of close-in planets down to Earth-size. The result is that Earth-size planets are just a common as planets twice Earth size. Remarkable.”

Continue reading “Surprise: Earth-sized Planets Are Common”

The Moon and Venus

Tomorrow morning will find a razor thin crescent Moon about 5° from a brilliant Venus just above the rising Sun. The Moon will rise about 05:50HST, with Venus already in the sky. With sunrise at 06:59HST the pair should rise about 13° above the sunrise. This is enough to allow the the Moon, only 1.9% illuminated to be spotted fairly easily given a clear eastern horizon.