Hello Professor Guyon,

In terms of what I have learned this semester, it's rather hard to pick a place to begin. Coming into your class, I have had very little (and I mean very little) exposure to anything astronomy related, the most relevant being discovery channel documentaries I'll occasionally watch with my family after dinner. The first thing I wanted coming in was a general grasp on how planets were detected (having read the course description) and I feel I got more than I was expecting. Going into the first project, I understood the general concepts behind radial velocity methods from what I was able to collect through online papers and class lectures but the time spent going through project 1 really solidified for me the relations and gains in using radial velocity measurements in tandem with transit data (for the fortunate case that planets will provide both). In addition, the difficulties in gaining transit data on earth-like planets due to the fact that to record multiple transit would require years of commitment in obtaining data (for multiple revolutions). On that particular project, my primary focus was to focus on transit depths (more particularly the expected radii of the planet) given appropriate estimations of planet composition. By doing so, I had to look into other factors that would pop up simply because they cannot be ignored in such an estimation, so consequently I had to look into the age of the star, the presence (or lack there of) of a core within the planet, it's orbital size, and whether or not proximity of the planet to the star will cause it to bloat. I also learned how the radius of say a hot jupiter will change over time with the change happening largely on the mass of that planet. In addition, I learned about the considerations needed in terms of noise (and where they originate) and how to correct for it (i.e. scintillation noise from atmospheric inconsistencies and are fixed by larger apertures, multiple apertures, larger integration times, etc.). With the given considerations, telescope sizes can be determined by considering wavelength bands, duration of observation, as well as elevation .

From the second project, I focused on the location, structure, and delay aspects of the interferometer particularly what considerations need to be taken such as light pollution as well as space to accomadate for the baselines necessary (driven by the size of the planet we wish to resolve). I also learned how the structure can be driven and complicated by this baseline as well as the pros and cons of fiber optics vs. vacuum tubes for the necessary delay lines. With regards to this project, I further learned about the possibilities gained through the use of differential imaging in order to determine oblateness of planets as well as possible satellites. In this project, I also learned about the wavelength considerations and effects it has on design of the telescope; lower wavelengths need longer baselines for example. With regards to the telescope, the size will need to be driven high due to the necessary photon flux, the cophasing requirements as well as the amount loss due to the delay lines. If this telescope were to be larger than the dimensions defined by the Fried parameter, then the system is see-ing limited and would require adaptive optics.

In the final project, this ground based interferometer was put in space with the greater challenge of imaging the exoplanet, with hopes of resolving geological features as well as obtaining atmospheric data. For this to happen, spectroscopy would be required in order to compare the transmission lines of our planet against the exoplanet's. With this project, I looked into the formation of the telescopes without a rigid structure due to the restraints from looking in the IR. With extremely large baselines in space being rather difficult, a lot can be remedied by utilizing a hypertelescope array in a parabolic fashion. With this project, I also learned the necessities and gains through coronographs and the basic structure involved i.e. the employment of a mask at the first focal plane in tandem with another mask used together with the ultimate goal of cutting the light from the parent star (leaving just the planet's).

In conclusion, I'm extremely happy I took this course. Even though the material was a little out of my comfort zone, I feel like I came out for the better. Thanks for the excellent class Professor and all the help you've provided throughout the semester.