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Showing posts from May, 2013

Taking the Python Plunge

I'm finally doing it. I'm learning Python through Codecademy's online tutorials.

So far, I really like Python. Everything is natively object oriented, so every variable is born as an object. Working within the paradigm has already shown me how much time I spend wrestling with IDL to make it work more like an object-oriented programming language, when it simply isn't. I've been known to call my style within IDL as Pseudo Object Oriented Programming, or POOP. It's often just as ugly as it sounds. So, philosophically, I'm finding that Python is well aligned with my programming style and needs.

Big ups to my student, Tim, for helping me with some of the nuances of Python arrays and syntax. He also pointed me to the Enthought Canopy programming environment, which is a great way to write code. Think of it as IDL's Development Environment, but less clunky.

I'm planning to start a new research project built solely on Python. It's a bit daunting, but I …

Minerva update

Last night we tried to get the autoguider working, but were thwarted by a loose USB power connector (we, meaning Mike working with me looking over his shoulder :). Fortunately, Mike stuck with it and fixed the problem earlier today. While Mike was working on the cables, I observed Saturn through the eyepiece on the other Naysmyth instrument port. Here's a picture of Saturn I snapped by putting my iPhone camera up against the eyepiece.


Trust me, this is not nearly as impressive as seeing it with your eye! Even from Pasadena, with 3.5 arcsecond seeing, I was able to clearly make out Titan and three other, smaller moons. 
Tonight we'll continue working on the autoguider and perhaps start testing the photometric precision of our imaging system. 

Friday Afternoon Music Break

A little stellar astrophysical hip hop by Kilo Kish:

Chinese Proverb Apropos to Time Domain Science

Via Jay Anderson (STScI): "The best time to plant a tree is twenty years ago. The second best time is now."

This is extremely valuable advice for anyone doing astrometry, Doppler-based planet searches, or any other science that gets better with longer time baselines. When's a good time to start your monitoring? 20 years ago? The next best time to get your survey up and running? Right now!

Liveblogging LathamFest Part 2

We're all caffinated now!

Stéphane Udry and The Role of Radial Velocities in the Quest for New Earths

Stability is key. Many aspects to stability! Two methods of precise RVs: absorption cell and simultaneous emission lamp. These calibrate the wavelength scale and instrumental profile.

Using a Fabry-Perot with HARPS shows that there are irregular pixel spacing on the CCD, which may be responsible for various 1-year signals.

Controlling the instrumental profile requires fiber optic cables, which scramble the input light. Octogonal fibers are much better than circulular (cross-section) fibers. Big success at SOPHIE.

HARPS-N is the latest PRV spectrometer in La Palma, Canarie Islands. David Phillips (CfA) installed a laser frequency comb on HARPS-N, tuned to work in 500-600nm bandpass (author note: previous LFCs only work in NIR). Difficult to faint stars with HARPS-N, so portion of 80-night GTO time is used for high cadence on bright stars. Shows RV time series of stable stars (author…

Liveblogging LathamCon

Jason Wright liveblogged the Dave Latham celebration yesterday, here, herehere and here. I'll continue for day 2.

The first session is The Legacy of Multi-Planet Systems and Photo-dynamics.



Dan Fabrycky is first up with It's All About Time. Before Kepler, Gl876 and the Pulsar planetary system were only systems that required dynamical fits to explain data. RVs and timing are 1-D measurements. Hard to get 3D info from 1D measurements.

Transit timing variations (TTV) technique first published circa 2005, could be used to discover planets, but initially only really used to place limits on additional planets in known transiting systems. More and more data led to more and more upper limits. Frustrating. But because companions to hot jupiters are rare. TTVs took 5 years of toil to little avail.

Kepler brought an embarrassment of riches for TTVs, seeing variations up to 1 day. What's embarrassing is that there are so many we haven't analyzed them all! Dan shows lots of TTV O-…

Dave Latham's need for speed

I'm in Cambridge, MA for the celebration of Dave Latham's 50 years in astronomy. Dave is an astronomer at the Harvard Center for Astrophysics (my soon-to-be home) and one of the pioneers in the field of precision radial velocity measurements. In fact, in 1989 he found the first planet, HD114762b, which is now known as Latham's Planet (read here or see Latham et al. 1989).

At the celebratory dinner I learned that, among many other interesting things, Dave was once a world-class endurance motorcycle racer. Seriously. He was once the best in the US and ranked #14 worldwide. He was even sponsored by Kawasaki Motorcycles who provided him with a competition bike. Here's an ad I found after a bit of Googling:


The caption reads
Dave Latham is an astronomer for the Smithsonian Astrophysical Observatory, a profession which demands technical precision. He is also a motorcycle competitor---a gold medal winner at the Isle of Man I.S.D.T. Dave chose the Ossa bike for his competition…

How a differential works

No, not a differential equation. But a differential. Here's a wonderfully clear tutorial that was brought to my attention by fellow astronomers, Cullen and Tom, over dinner tonight:



Where are all the women professors? Among the recently hired!

I recently wrote a series of posts entitled "Where are all the women professors?" here and here. I began with a simple premise: "men and women are equally capable of succeeding as professional astronomers. There is no inherent (intrinsic) difference in mental capacity, creativity, ability to learn, or any other factor that plays into the success of an astronomer." From there I examined the role of unconscious bias as one of the factors in a "leaky pipeline" that has resulted in an underrepresentation of women among astronomy professors.

The post was picked up by the Women In Astronomy Blog, and a commenter wondered, "What is the fraction of women hired on tenure track during the same time period as the statistics of the graduating students?" While the present representation of women among various astronomy faculty hovers somewhere around 15%, is there evidence that there have been improvements in recent years? The question stuck with me, but I w…

This is water

Here's an incredibly inspirational speech and video (via Trevor's Google status). From the Youtube video description:
In 2005, author David Foster Wallace was asked to give the commencement address to the 2005 graduating class of Kenyon College. However, the resulting speech didn't become widely known until 3 years later, after his tragic death. It is, without a doubt, some of the best life advice we've ever come across, and perhaps the most simple and elegant explanation of the real value of education.We made this video, built around an abridged version of the original audio recording, with the hopes that the core message of the speech could reach a wider audience who might not have otherwise been interested. However, we encourage everyone to seek out the full speech (because, in this case, the book is definitely better than the movie).

The Kepler Mission ain't over till it's over

From Joseph, who works at JPL:
Don't be so quick to bury Kepler. There is a famous quote from Mark Twain: "The reports of my death have been greatly exaggerated." Kepler is now in Point Rest Mode, with very low fuel consumption, giving the reaction wheel jockeys a chance to revive reaction wheels #2 and #4. It ain't over 'till it's over. C'mon Kepler, you can do it!

Kepler: RIP

Kepler's reaction wheel #4 has failed, leaving the telescope unable to point precisely. It has been an amazing ride. We now know of 2740 transiting exoplanet candidates, many which are still awaiting confirmation and characterization. We know of circumbinary, Tatooine-like planets. We've found eclipsing degenerate objects tidally deforming their companion stars. We've found compact systems of tiny planets parked right next to their stars. We now know that small planets abound throughout the Galaxy. The field of exoplanetary science, as well as astrophysics in general has been forever revolutionized by NASA's highly successful Kepler Mission.

But now it's time to say goodbye.

I did a phone interview yesterday with a reporter from the LA Times. She asked if I was mourning. I hadn't thought about it until then. But yes. Yes, I was mourning. My group about to have 5000 hand-picked red dwarf targets added to the Kepler observing list. Those stars and their myriad sm…

Exoplanets Explained

Here's a continuation of my group's conversation with Jorge Cham about stars, planets and everything.