The news is not that fresh, but I just want to register the information if someone missed the buzz of the last days or if this text was retrieved from an old and well-preserved server on the distant future when humanity has deceased. In case you didn’t know, Brazil is in its way towards being the first non-European country to be a member of ESO, the European Southern Observatory. The whole process started back in 2010, when the Ministry of Science & Technology proposed an agreement to ESO. At that moment, Brazil was enjoying fruitful times, with a steadily growing economy and a general improvement on the people’s lives, especially the poor. Things were good, so the 270 million euro investment on membership didn’t seem like too long of a stretch.
However, investments in science and technology are also slow to get on going in this country. It is now 2015, dollar and euro went skyward, our economy is stagnated, and there is a climate of political uneasiness. Things are rough now. Even so, the slow pace has led us to what seems to be a happy ending. In March 19th, the Congress finally approved the investment (which they generally called a cost) on ESO and the membership. The political strife between the federal government and the [mostly] opposing congress may have been a blessing: it is said that they only approved the membership because president Dilma Rousseff was showing signs of backing off of the agreement.
After going around back and forth through a series of bureaucratic assessments, the process went to the Senate, and on May 14th, they also approved the investment on ESO. As someone has put out on Twitter: Brazilians woke up next morning being the co-owners of the most advanced ground-based telescopes on Earth. Today, May 19th, the Senate has promulgated the approval through the Diário da União.
The Senate didn’t put much of a fight to bar the entrance to ESO. In fact, they seem to be in accord about the benefits to our country on becoming a member. Here’s what is said in the official statement by the Senate (my own translation):
“Given what was shown, we are certain that [the membership] is an investment that will give our country an immediate return. Furthermore, there are already many research projects whose success was only attained because of the efforts of our astronomers and the observation time that was conceded to them, in addition to the perspectives of participation by our companies and institutions on the E-ELT construction. On the other hand, we have to keep in mind that this is, above all, a long-term investment in science, technology and education by our country.”
That wisely said, we are now [arguably] one step away from finally becoming a member of ESO: we need the president Dilma Rousseff to approve the project of law. This is it, people, we are almost there! Even though there is this rough political climate in Brasília, it is highly unlikely that the president will overrule the decisions of the Congress and the Senate. Will she survive long enough as a president until then? Well, that’s another story, but I would bet that she will.
Anyway, this is where things are now. I am very happy, not only because we will continue to be able to use ESO’s facilities for our research, but also because this is a huge and inspiring step for us. Astronomy was judged by many politicians to be frivolous and unimportant given the core issues that our country has. But even so, with the efforts of many people, we are almost there. We have long ways to go when it comes to science, technology and education, but it is also true that we have never seen such good times in Brazil. Baby steps.
Featured image: an excerpt of the Brazilian Senate’s report on the decision taken on May 14, 2015
Are we alone? This project is part of one of the biggest efforts of modern astronomy, which is trying to answer questions such as “can we find another Earth?” and “is the Solar System common?”. But these are very general questions, and there are many ways to look for the answers. For instance, we can turn into the closest stars in our own Galaxy, and look for signatures that indicate the presence and characteristics of (exo-)planets orbiting them.
The majority of exoplanets discovered in the latest decades are hot Jupiters, massive gaseous planets that orbit in a very tight trajectory around their host star. This was unexpected to us, when we first got these results, because we were very used to our own Solar System, with its rocky planets in the inner part of the system, and each one relatively far away from the Sun. A hot Jupiter can be as close to their host star as a fraction of Mercury’s orbit. So, yes, that is weird. The following plot shows a compilation of the exoplanetary systems that we have discovered so far. Most of what we see are single planets instead of various planets orbiting a star, but this is probably a bias, due to limitations of our instrumentation and methods.
When we look at these stars, sometimes we see variability in their brightness, and there are many phenomena that can cause it. One of the causes is an exoplanetary transit, and the variability this case is very tiny, of the order of millimagnitudes. But they can be observed, and this is what many astronomical surveys do: they look for dips in stars’ brightness, all through the sky.
Although there is Kepler to perform surveys from space, there are too telescopes here on ground doing this work, which is the case of KELT, the Kilodegree Extremely Little Telescope. And when I say little, I really mean it: the telescope is as tiny as a photographic camera. When I first saw a picture of it, I though “wow, that’s a cool mount, but why the hell did they put the picture of the mount without a scope”? It came to me as a surprise when I took a better look at the picture and noticed that the telescope was already there, and it’s actually just the CCD box with lenses attached to it. There are actually two KELTs, one in the northern hemisphere and one in the south. “Kilodegree” is because the field of view of the telescope is very big, which is caused by the awfully short focal length of the scope. It’s tiny after all, so no surprise there. But we should not think little of this instrument: it is powerful enough to see very slight brightness variability in many stars at the same time, and this is where its power resides.
The problem with KELT is that, sometimes, it’s difficult to disentangle variability from other possibles causes. And this is where we come. KELT needs other instruments to make follow-up observations of their candidate targets. We are using the B&C 0.60 m telescope from Pico dos Dias Observatory to make follow-up observations for KELT South (which is located in South Africa). Our job is to observe stars for which transits are predicted, and make light curves of them.
If you are not familiar with light curves, they are plots of a star’s brightness through time. They are important tools in the study of variability, and many discoveries of exoplanets were done using such plots. There are various ways to construct these. One of them is to take consecutive observations (generally in the same night and in the same instrument) of a target star, and compare its brightness with other stars (let’s call it the “standard stars”) in the same field. The standard stars must not have an intrinsic variability, otherwise we will not be able to compare their brightness in time with our target star. This method is called differential photometry, and it is much more accurate when compared to absolute photometry, which consists on calculating the brightness of a star from “principles”, directly taking into account effects of atmosphere and instrumentation – the problem with this method is that the uncertainties will be much wider than the variability we are trying to observe (remember it’s of the order of a few millimagnitudes).
When we have two stars in the same field of view, if it is small enough, we can assume that they are affected in the same way by the atmosphere and the instruments, and this approximation is, most of the time, good enough. Because we want to compare brightness, what we do to minimize the uncertainties as best as possible is to try to get as much light as we can in an image. Getting photons is like counting, which is a Poisson process, and statistics geeks will remember that the uncertainty in a Poisson process is proportional to the square root of the number of occurrences. An exoplanetary transit takes some time: from a few dozen of minutes to a couple of hours, so we should aim for a time resolution of a few minutes, generally. But if the star is too bright, the CCD can saturate in just a few seconds. In order to gather more light as possible in a single image, we can try de-focusing the telescope a little bit, so that the CCD doesn’t saturate quickly and we keep on a linear scale for a longer time. All this contributes to having an accurate photometry, which is what we are aiming for.
Data reduction follows the usual algorithm: bias subtraction followed by flat-fielding. But after that comes the most interesting part: doing the actual photometry. As I said, we are using differential photometry, but there are some subtleties to it. The way we do it is to measure the brightness of the target star and the standard stars inside of circles or, say, apertures in the image (which is why this sub-procedure is called aperture photometry). We then follow to compare their measured brightness by subtraction in a log-scale, and this results in differences in the scale of magnitudes. These differences are then plotted, and what we have is, hopefully, a “rough draft” light curve of the target star. The plot will be, however, in an arbitrary unit for the magnitude. What we do is to normalize the differences in magnitude, by establishing that the highest values of differences should be zero (which is the same as saying that the difference of brightnesses of two non-variable stars should be null). If our target star has a variability, the difference in brightness will be seen as a shift from zero.
We have performed two observation sessions so far. The first one was more of a test, to see if the B&C telescope would be suitable for this kind of research. Most of our results at this point come from this first session. The second session was performed in the beginning of April and had two targets that were exoplanet host candidates, but the weather was crap. The following plots show the light curves that we have obtained so far. These results are very preliminary, though, because the observations weren’t, well, very good. We weren’t very experienced with transit observations, so we messed up on something very important: we didn’t get many exposures before and after the transit, so the bulk of the data is too concentrated during the event. Also, the plotted uncertainties are completely systematic, no statistical uncertainties were obtained thus far. Conditions were not photometric in either sessions.
Data reduction was done in IRAF. We performed differential photometry of the target star using the software AstroImageJ. Plots were created with Python, using NumPy, Matplotlib and Seaborn.
WASP-19 is a confirmed exoplanet host, with a transit depth of approximately 20 mmag. In our observation, we could only get the end of the transit, because the beginning was washed out by twilight. And we can see that the observed transit depth agrees very well with the predicted. Additionally, we observed KS21009352, which is an eclipsing binary with a depth of 30 mmag. Again, as we can see in the light curve, our observed depth agrees very well with the prediction.
Another interesting result is for the light curve of the confirmed exoplanet host WASP-104, which has a transit depth of approx. 15 mmag. The photometry we performed produced these weird outliers, and it was caused by cloudiness (it also happens for the targets of the second observation session, but it is even worse, reason why I didn’t plot them here). However, if we get rid of these outliers on the transit of WASP-104b, we can see that we managed to get a reasonably good agreement with the predicted depth (but the uncertainties are bigger when compared with WASP 19 and the eclipsing binary). I wonder if there is a way to improve the uncertainties (if you know something, please let me know in the comments).
We plan to have several other observation sessions throughout the year, this time observing actual exoplanet candidates for KELT South, so more results are coming. And hopefully better ones. I’m keeping a project page about this research that I will keep updated as things go on.
In the beginning of March, we went for an observation at the good and old Pico dos Dias Observatory (OPD), here in Brazil. I think it was the first time I went there during summer, which is the rainy season around these parts, so it’s not actually a good time for observations. We wanted to assess the B&C 0.60 m telescope in its potential to do followup observations for KELT (Kilodegree Extremely Little Telescope – pretty funny name: a bit of a satire on ESO’s “very large” telescopes, I imagine), which surveys the sky looking for hot Jupiters around bright stars. So yeah, we went there to hunt some exoplanets.
To do that, we used differential photometry, a method that compares how the brightness of different stars in a given field of view vary with time. In our case, we wanted to see how the brightness of the exoplanet-host dipped when a transit occurred. To do that, we need as many photons as possible to fall on our detectors, so we can have measure the dip with a bigger certainty. Results were very interesting, and I will write a more complete blog entry about our observations in the near future. But, while we were there trying to catch the light (or rather, the shadow) of exoplanets, I was, as always, trying my hand on some night sky pictures.
While I left the telescope doing a very long series of exposures, I set out taking my camera and tripod to do some imaging. And during one of my first trials, I was lucky enough to have a really bright meteor cross the sky and go over the 1.60 m telescope, and even more lucky to have my camera exposing at the time. And further lucky to have set a high ISO, so the meteor stood out beautifully in the picture. Unfortunately, since it was one of the first pictures, the camera wasn’t focused very well (in fact, it was pretty terrible), so it didn’t end up as good as it could be. Also, the Moon was 88% illuminated, so we get this effect of “daylight with stars” in long exposures (in all pictures, click to embiggen).
However, things weren’t that bad, because the sky went completely dark after around 4 AM, when the Moon set, so there was this short window of darkness until the twilight, and I was eager to take advantage of it. I haven’t had many chances of taking pictures in really dark places with really dark conditions before, so this was a good opportunity.With the help of some bright stars, I managed to focus the camera and I took these two following pictures. The first one was taken using ISO 3200 and, luckily enough, I got another meteor (a dimmer one, though) and a satellite! The second one was taken with ISO 1600, which has less noise, but it is less sensitive, and so I had to take more exposures, resulting in longer star trails (I don’t have an equatorial tracking tripod). As you can imagine, we have to work with a trade-off between more light and noise/trails.
Here are two other shots taken aiming towards the domes of the observatory, and they are probably my favorite ones. Not only because they look fairly good, but because it was actually very fun to take these shots. The site was so dark, that it was hard to find my way around the observatory until my eyes didn’t get used to the darkness (it took about 10 minutes). Once your pupils are fully open, we can see so many stars in the sky that it is difficult to find the asterisms of the constellations.
I think those were very productive nights. We obtained good results from the observations, I got a chance to take pictures in really dark conditions, and food was good. The food from OPD is never a let down. Word is that, when the weather is bad, astronomers like to spend their time lounging at the 1.60 m telescope pantry. Luckily we didn’t need to do that.
Since I started studying Python programming, I’ve been creating some sample codes, here and there, that solve physics problems. Most of them are exercises from books, the internet and occasionally from school assignments. I have a lot of fun creating them, even though they can be quite difficult to compute sometimes. Because of that, I started a very laid back project called Pysics, which is basically publicizing a compilation of these exercises, so that they can be used by other students.
Initially I was creating a program on GitHub, but since I got to know this amazing tool called IPython Notebook, I realized that this should be the best manifestation of Pysics, without question.
So, here it is, the Pysics notebook one. You can also download the ipynb file here. It basically contains four exercises: plotting the electric field produced by point-size electric charges, calculating the time-evolution of a coupled triple pendulum, computing Bessel functions and simulating the diffraction pattern of a telescope.
I plan on working on one or two more notebooks, which I will release someday (not sure when, for my graduate school starts in just a few weeks and I will be busy with the preparations). But, for now, I hope this notebook can be useful and inspiring to you.
Featured image: the diffraction pattern produced by a point-like source of light as seen on a telescope.
Featured images: Artist’s impression of the E-ELT. Credit: ESO/L. Calçada
In 2009, Brazil showed interest in being a state member of the ESO (European Southern Observatory), one of the current leading astronomy consortia that you probably already know of (if you don’t, go here). If Brazil managed to get the membership, it would mean a huge boost to our astronomy and a lot of opportunities for our companies to participate in manufacturing the instruments. ESO’s website has an extensive dedicated FAQ about this affair. Brazil does already have access to the facilities in Chile to do science, but we will only be able to participate as a state member if we paid 130 million euros. This money is of essential importance for the construction of the E-ELT, the 40-meter diameter European Extremely Large Telescope, for which things have already started with a bang in the Andes of Chile. This telescope will be our most powerful eyes for the observation of extrasolar planets, the first objects of the universe, supermassive black holes and the search for dark matter and dark energy.
Now, how important is Brazil’s money for this endeavor? As I said before and reiterate here, it is essential. The funding or E-ELT was divided in 3 parts: one from ESO’s budget, one from the other state members and one especially from Brazil. These guys are counting on us. This is because doing astronomy today is very expensive, especially if you want to look at the unexplored frontiers of the universe, so we need consortia, and we need the collaboration of many countries to make things happen. And this actually make me very proud of being an astronomer, because it’s a science that brings nations together.
However, you probably are already aware that the process of Brazil becoming a state member of ESO has been dragged along for quite a while, to say the least. And the problem is in our side: the government is still analyzing the membership, even though the former Minister of Science and Technology, Sergio Machado Rezende, asked for it in 2009. Something similar is also happening in our country’s decision about becoming a member of CERN. Unfortunately, that ESO’s FAQ I linked before does not contain an updated information on what grounds the decision are at the moment. It does say that Brazil was supposed to ratify the membership by 2013. But, so far, we don’t have an answer, and this is kinda embarrassing.
So, this is where things stand right now: the membership to ESO is under the appreciation of the Câmara dos Deputados (Chamber of Deputies), our equivalent of a Parliament. More specifically, it has to be approved by 3 commissions, 2 of which have already approved it, and so far it is waiting for the feedback of the rapporteur on the Commission of Finances and Taxation. The project is filed under the code PDC 1287/2013, and the most updated information can be seen here, but it’s in Portuguese, and I’m pretty sure there is no translation for this website. The process is already in regime of urgency, so at least they have made it clear that it is “due for yesterday” (a common expression around here). The good news is that the project has been approved by all (too many) of our bureaus, but, and here comes the bad news, since May 2014, it has been stuck at the Chamber of Deputies So far, it was presented 2 times in their sessions, one in May 29th and another in June 5th, and both times the project was not appreciated. They don’t state a reason for it, but I assume it was because they ran out of time in the session before doing the appreciation.
So, when can we expected a final decision about all this? Well, I’m afraid there is no way for me to give more information on that. An explanation on all the delay is that in July and August, there was that thing called World Cup, and then the deputados probably went for winter vacation. This October, there were elections here in Brazil, so politicians have been a bit busy on self-promotion. It’s not a justification though. I sure do hope that these guys make things work until the end of the year, so we Brazilian astronomers don’t need to feel ashamed anymore of this postponing.
The astronomical community is making its part on the job too. There has been a lot of buzz in trying to push things forward. A group of young astronomers already sent an open letter to the deputies stating how important the membership to ESO is to science and innovation in our country. Some astronomy and industry leaders have also made it clear (if your Portuguese is good or you don’t mind using Google Translate: more on that here and here, for example) that this project has been delayed too many times, and if Brazil is kicked out of ESO (as it happened with ISS), it would be a huge loss to the country’s science and technology. On the other hand, professor Dr. João Evangelista Steiner, of University of São Paulo, points out that there are other means for Brazil to advance in astronomy, for instance, by participating in the Giant Magellan Telescope (apparently, a deal between the state of São Paulo and GMT has already been done, more here too), on which the allocated telescope time would be proportional to the investment instead of competing on unequal grounds with countries that already have an upper-hand with cutting edge astronomy (which will be the case with E-ELT). However, professor Dr. Marcos Diaz, also from University of São Paulo, says that the competition is healthy for scientists to make better and better astronomy.
One of the biggest cons of the membership is that it would be a significant hit on the country’s public money reserve. 130 million euros is equivalent to ~164 million dollars, or ~398 million reais, in today’s exchange rates. That’s a lot of money, and one of the reasons why the project is being analyzed so carefully and delayed so many times. According to the Brazilian Astronomical Society, on that regard, the Ministry of Science, Technology and Innovation has decided on June 4th of 2014 to propose to ESO an attenuation on the price of the membership, but so far there is no more information on that. Brazil’s last budget for scientific research in 2014 was ~10 billion dollars (more on that here, in Portuguese), among public and private money. But regardless of the price tag and the said inequality on the competition for telescope time, Brazil has made a commitment, and backing away from the E-ELT could mean to the rest of the world that our country is not ready to dive into such scientific endeavors.
I have signed up to receive an e-mail anytime the project gets updated (for instance, if the commission approves, disapproves or delays it), so I will write here on the blog every time something new comes up. Fingers crossed.
During the past weeks, I’ve been trying some astrophotography at my place. Not for the first time, because I have done it (not very successfully) before, but now a friend of mine (who is also into astronomy and photography) lent me this cool camera support for backyard telescopes. Although it is designed to work better with smaller cameras and cellphones, I can attach my Nikon DSLR into it by taking out the lenses and using it in the primary focus. So this is the good news. The bad news is: well, if you ever tried astrophotography, you will know better than anyone how frustrating and painful it can be at first.
Astrophotography is difficult. It is probably one of the biggest challenges I had in my life, one that I could not perform well yet. It’s not like you just stick a camera into a telescope, press a button and a beautiful picture magically comes out ready to be published and admired. There are many, many steps to do before you get something worth showing. In regular photography, I would say that your performance depends a lot on your mood, on how well you can frame and capture an image, on the ability to work your way around lighting, how well you know your own camera and even on your luck. Astrophotography, on the other hand, has so many technicalities and small details, that it can drive one person crazy. It’s not just a question of practice, because you’ll be seriously limited by your gear. For instance, it’s not every telescope that can take good planetary images, and it’s not every camera that can be controlled by a computer (I’m looking at you, Nikon). These are the bad news. But I know I shouldn’t expect much, since all my gear is among the lowest end available, but I guess it’s a good place to start, right? Another issue that I have not mentioned yet is that astrophotography is expensive, especially if you intend to buy things in Brazil. Just so you can have an idea, a telescope that costs US$ 100 in the US costs 4 times much here.
So, here are the main problems I am having, in order of importance:
Terrible telescope mount: probably the worst issue, because even my own steps around the scope can shake the exposure and create smudges and star trails. Also, aligning the scope with the south pole is a HUGE pain in the ass
Light pollution: very problematic too, mainly due to the large number of light poles around my house (I live in one of the main streets of the neighborhood)
Lack of software support for Nikon DSLR: seriously, if I knew that there was no software that could fully control a Nikon DSLR, I would have bought a Canon. I wish I had researched this better before I made the purchase
Notice:if you know a way to work around these issues (mainly the lack of software support for Nikon DSLR), please let me know in the comments or through an email!
But enough of the frustration and rant. I thought I would talk about it first so I would have an excuse for my pictures, which are not… that good… I mean, it’s not wallpaper quality but, hey: baby steps. One day I will have a good scope and live in a place with less light pollution. Until then, I will keep practicing. Another option that I want to try is to make movies with my camera and stack the frames using Registax. In fact, I have tried that with the Moon, but I could not get Registax to work well. I guess I need to learn how to use it beyond just clicking a few buttons. Anyway, here you go (click them for a 1080 px version, even though I don’t recommend for some of them):
And here is my favorite picture of them all. For this one I didn’t actually use the telescope, just the camera on my standard tripod. But it turned out to be cool, even though the light pollution hurt a lot of it.
If you’re interested, this is my gear (as I said, these are very low end stuff for astrophotography):
Telescope: Celestron PowerSeeker 127EQ
Camera tripod Hama Traveler Compact Pro
Camera telescope support that I don’t know the brand (see picture)
I cannot resist mountains, especially if an observatory sits up there. And that’s why when a friend called me to go up to the Pico dos Dias Observatory for the weekend, I accepted without too much thought. Screw classes and appointments, Astronomy awaits to be done! So, here I am, giving some support to the observations and enjoying the free time to take pictures. There is a problem though: the Moon is almost full, so the brightness washes out the fainter stars and it illuminates the environment, making it look like day. So, pictures of the night sky are not that plentiful.
On the other hand, observations are running somewhat smoothly. Even though the data is not for any of my work, I try to be helpful, so I am exercising my rusty observational muscles a little bit. Machines are incredibly interesting, so operating a 1.60 meter telescope is always a blast. It is like a car, every little piece has to be working perfectly in order to have a smooth run.
From my experience, every single day, for every single telescope I worked with, there was always a problem, a nuisance that took a few minutes or even hours to be fixed. I remember when a friend and I were observing at this same telescope, suddenly the dome stopped working and it turned out to be a mechanical failure in one of the gears. In La Palma, I recall we having some problems with the communication between the computers and the telescope. And here, so far we had an issue with the dome controlling, but a simple reboot in the dome system was enough to do the trick.
I’m having a good time taking pictures from this visit to Pico dos Dias Observatory. Making compositions with an almost full Moon is a bit tricky, because you can’t use longer exposures (or a larger aperture, or larger ISO, for that matter). But it is fine, we do what we can. Actually, the moonlight can make some pretty cool effects, you just have to learn how to explore the surroundings. For instance, the mountains that would otherwise be completely dark in a moonless night show their beauty and magnificence under the satellite’s illumination. And the effect becomes even cooler if there a few city lights to help compose the frame. But they are crappy for Astronomy purposes, light pollution is not cool for that. So, yeah, I’m a “half-full cup” kind of guy, you gotta enjoy the good aspects of everything. So, kick back and take a look at some of my favorite pictures, and I hope you enjoy them. At the end of the post, you’ll find a photosphere I took here at the observatory yard.