A compilation of my observing trips with fun facts, tips, and deadlines for proposals.

Space Telescopes

The Earth's atmosphere is quite noisy and sometimes hinders the data from ground-telescopes. So we go to Space! The resolution without the atmosphere is so much better that we obtain better science and wonderful images. We can therefore discover and study high-redshift sources in more detail.

The Hubble Space Telescope orbits around the Earth once every 90 minutes, so we can obtain images all over the sky! Credit: ESA.

The Hubble Space Telescope in orbit around Earth

The James Webb Space Telescope

JWST will revolutionize our view of the Universe. It has a special focus on high-redshift astronomy as it will be looking in the near and mid-infrared with an incredible resolution. I Co-PI a proposal with Dr. Micaela Bagley to confirm z ~ 9 galaxies and measure their ionizing power Looking forward to the data!

Running some of the last few tests on JWST before launch in December!
Credits: NASA/Chris Gunn.

The James Webb Space Telescope under construction in the lab

Optical Ground-based Telescopes

Reflector telescopes using mirrors are cheaper to make and can be bigger than refractors using lenses. The bigger in diameter the mirror, the more distant objects can be observed. 10-meter class telescopes are ideal to study the EoR since we need to gather as much light as possible from high-redshift sources.

Mauna Kea Summit in Hawaii hosts 10-m class telescopes: Keck I and II, Subaru, and Gemini (N). Image credit: Keck Observatory

Mauna Kea Observatory in Hawaii under the night sky

Radio Telescopes

Radio astronomy began by accident in 1932 when the engineer Karl Jansky, was investigating natural sources of inteference in telephone communications. He constructed an antenna and bumped into the central Black Hole in our galaxy. In radio, we can study the cold dust and gas from high-z galaxies.

We can observe our science targets during the day! The Sun's radio emission does not bother us, unlike it does for optical Telescopes.
Credit:(ESO/NAOJ/NRAO)/W. Garnier (ALMA)

The ALMA array of antennae in the Atacama Desert, Chile

W.M. Keck Observatory

Located in The Big Island of Hawaii, the observatory is at about 4,000 MASL on the dormant volcano of Mauna Kea. The altitude and weather conditions make this observatory the perfect place to hosts two 10-meter class telescopes.
2022A call for proposals.

Observing with Steve and Rebecca. Bottom: Keck I mirror calibrations and spectra of potential high-z galaxies from MOSFIRE

Dr. Steven Finkelstein, PhD(c)
										 Rebecca Larson and Sofía Rojas at the observing headquartes in Hawaii.

The Texas team observing at Keck: R. Larson, C. Papovich, T. Hutchison, S. Finkelstein and me.

The Texas team observing at Keck: R. Larson, C. Papovich, T. Hutchison, S. Finkelstein and me

Keck I and Keck II 10-m Telescopes. Credit: Keck Observatory

Keck I and Keck II 10-m Telescopes

W.M. Keck Observatory Headquarters, where we sleep in the day and observe at night.

W.M. Keck Observatory Headquarters

Astronomers don't go up all the way to the telescopes to perform the observations, we observe from the headquartes with computers set up to communicate with the instruments at the Summit. The telescope operators, experts on the instruments, are at the telescope and help us observe the whole night. We could not do it without them!

Nature is awesome around the Big Island, reminded me a lot of home!

Tropical nature in Hawaii

Visited Mauna Loa in 2018, just a week before the eruption of Kilauea, the other active volcano of the island.

Mauna Loa Volcano in the Big Island of Hawaii

Met the Pacific Ocean for the first time, even though I am from Colombia...

A view of the beach from the Big Island, Hawaii

La Silla Observatory

The European Southern Observatory (ESO) built its first home for telescopes in the Chilean Atacama Desert because of the beautiful night sky and dry conditions that are essential for optical telescope operations. Proposal calls vary depending on the telescope.

Telescopes at the La Silla: Left: The MPG/ESO 2.2 m telescope I used for 14 straight nights. Center (squared dome): The New Technology Telescope NTT. Right: The ESO 3.6m telescope, the biggest one here.

Telescopes at La Silla Observatory

The MPG/ESO 2.2 m telescope getting maintance in the morning.

The MPG/ESO 2.2m Telescope at La Silla

At the telescope there are three instruments to do observations. I use GROND to look at the quasar candidates in all available bands from optical to near-IR k and identify the photometric break indicative of the quasar's high redshift nature.

GROND instrument at the MPG/ESO 2.2m Telescope

The astronomer's work station from where I manage the telescope. It's important to keep an eye in every screen to make sure the telescope and the observations are working fine.

Computer screens
													to monitor the observations at the MPG/ESO 2.2m Telescope

One of the most important screens is the weather monitor. It warns us when clouds are coming and when humidity levels rise. Droplets of water entering the telescope dome is very bad for the mirror and instruments. You have to do an emergency close when buttons go red.

Monitor showing the weather at La Silla

Living the astronomer's nightmare: clouds at dusk.

A photo of the sky
															 at La Silla at dusk (unfortunately with cloudy weather)

We have friendly visitors all day around the observatory.

Photo of a donkey hanging out at La Silla

The astronomer's sleeping area, with the Andes in the background. First time I saw the Andes naked, in Colombia they are very green covered with thick layers of vegetation.

Sleeping headquarters at La Silla, with the
															Chilean Andes in the background

Pretty much the only wild flower around the Observatory. This area of Chile is very dry, good for telescopes but not for plants.

Random flower growing in the
																desertic conditions of La Silla

La Silla also hosts other non-ESO owned telescopes such as the 1.2 m Swiss telescope. Cutest telescope I've seen.

The 1.2 m Swiss Telescope at La Silla

Paranal Observatory

At Paranal are the four 8.2-m Very Large Telescope VLT. ESO hires astronomers who become experts on the telescopes at Paranal and observe all the science targets from accepted proposals. It is thus rare to have visiting astronomers outside of ESO, I was very lucky! Next call for proposals.

Visiting Paranal! (the VLT is at the back.)

A photo of me and in the background are The Very Large Telescope at Paranal in Chile.

The incredible VLT at the top of the mountain. The surroundings are extremely dry and desertic, not the tiniest wild plant. This is the closest I will ever be to Mars.

A closer view of The Very Large Telescope at Paranal, Chile.

At the VLT UT 1 'Antu', which means Sun in Mapuche, the indigenous original inhabitants of this area of Chile.

Sofía Rojas in front of the VLT unit 1 8-m telescope

From Paranal, you can see the construction of the upcoming European Extremely Large Telescope E-ELT, a 40-meter telescope!

Construction site for the European Extremely Large Telescope (E-ELT)

This is the entrance to the residences where astronomers eat and sleep. It is located underground and far away from the telescopes, you need a car to go up and down the summit.

Entrance to the ESO underground headquarters
																for astronomers observing at the VLT

When entering the residence, there is a complete change of landscape. It offers a more friendly and humid environment to counteract for the extreme dry conditions of the desert.

A look at the pool inside the ESO headquarters

The residence is very friendly and you get to interact with tens of astronomers and staff every day. Observers can stay up to 10 nights observing so they deffintely try to accomodate you with the best environment.

A view of a nice lounge with palm trees at
																	the ESO headquarters

The night sky truly is amazing at the top of the observatory!

A view of the sky at dusk from the VLT

Green Bank Observatory

Located in the Quiet Zone of West Virginia, U.S. All radio signals that could intervene with our observations are banned. We shall not use a microwave or turn on our phones, so all my photos were taken with a Kodak disposable camera (forgive resolution.) Next call for proposals

The Green Bank Telescope (GBT), one of the biggest radio telescopes in the world with a dish of 100 meters in diameter.

A photo of the Green Bank Telescope (GBT) taken from the ground

I look so tiny on top of the GBT!

Photo of Sofía Rojas on top of the
											100m dish of the GBT

We observed the Crab Nebula with the 40 feet antenna. First time I observed in the day, it felt weird but more resting.

Picture of a 40 feet antenna at Green Bank Observatory

The observatory's surroundings are beautiful! A lot of green and wild life. We had to use bikes to move around between telescopes, conference room and sleeping lounge.

Photo of Sofía in front of the GBT

A replica of the Karl Jansky's Telescope that observed the SMBH in the center of our galaxy. (Yes, this is an antenna).

Photo of a replica of the first radio antenna constructed by Karl Jansky

The Green Bank Observatory Science Center. Here we can use computers with ethernet connection to work on the data from the telescopes... and communicate with the world.

Green Bank Observatory Science Center

The Very Large Array

What is better than a single dish? An array of 27 antennas observing the target at the same time, creating a single telescope that can vary in size from 1 km to 35 km in diameter, depending on the location of the antennas. Operated by NRAO and located in beautiful New Mexico. Next call for proposals

Each of the 25-m VLA antennas are identical. This one is ready to be climbed!

One of the antennas at the VLA, ready for us to climb on and take in the landscape

On top of the antenna dish showing the receiver bands and the subreflector on top hanging from a swivel!

Photo on top of the VLA showing the
											reciver bands on top of the primary dish, and the subreflector on top

Selfie with the 8 receiver bands! I have worked with all of these.

Selfie with the receiver bands

In ascending frequency: L, S, C, X, Ku, K, Ka, and Q bands covering continuous frequencies from ~1 Ghz to 50 Ghz.

Close up picture of the eigth receivers on top of the antenna

Bottom of the L-band receiver, this size is equivalent to one pixel of your phone camera. It is much bigger because the radio photons are much weaker than those in visible light that your camera captures.

Photo of the bottom of the L-Band receiver

The antennas were on A-configuration, meaning covering the largest baselines of 35 km, so I could barely see the other 26 antennas from my position.

VLA antennas in A configuration

This is the transporter used to move each antenna on a special railway to get from A to B, C, or D-configuration.

Photo of the antenna transporter

Couldn't forget taking a picture of the wildlife around the observatory, some antelopes came to say hi!

Photo of Antelopes at the VLA

The VLA site also has its own Radio Sundial.

Photo of Radio Sundial at the VLA

Kitt Peak Observatory

The Observatory is part of the National Optical Astronomy Observatory NOAO. It is a city of telescopes in the Kitt Peak mountains of Arizona as it hosts over 20 telescopes of different sizes and for various astronomical objectives.
Telescopes info and calls for proposals.

I went to Kitt Peak for two nights to assist a grad student on his observing run.

Sofía visiting the Kitt Peak Observatory
													in Tucson, Arizona

We observed at the Mayall 4-m Telescope. with the NEWFIRM camera in the K-band to make a catalog of z ~ 4 galaxies.

The Mayall 4-m Telescope with tiny Sofía in front

A few telescopes at Kitt Peak as seen from the other side of the mountain.

View of a couple telescopes at Kitt Peak

This is the Mayall telescope!

Sofía pointing at the  Mayall 4-m Telescope
													from the opposite mountain at the Kitt Peak Observatory

An overview of the observatory and the many telescopes it has, taken at the visitor center.

A small scale model of the Kitt Peak Observatory

The McMath-Pierce Solar Telescope. Truly an architectural masterpiece for a telescope dedicated solely to looking at the Sun. I visited when it was still functional for research (2016).

Photo of the McMath-Pierce Solar Telescope

McDonald Observatory

Owned by The University of Texas at Austin and located in West Texas, this is the first observatory I ever visited. All UT astronomy undergradutes have the opportunity of going on observing nights either for research or outreach. There are five telescopes and calls for proposals are trimestral.

The 82" Otto Struve was the first telescope at McDonald built in the 1930's. The telescope is at the top of a five story building. All other floors are a big library!

The 82-inch Otto
												Struve Telescope at McDonald Observatory

The Harlan J. Smith is a 107" telescope. It is one of my favorites to use and visit because it has the Tull Spectrograph. This coud´e spectrograph occupies a whole room that you can visit and see all the mirrors and instruments that help redirect the light from the observations to the detector.

The Harlan J. Smith 107 inch telescope at McDonald Observatory

The Hobby-Eberly HET 10-m telescope is certainly the one with most advanced technology. Unlike other telescopes, its mount is fixed at an angle and thus only observes 70% of the sky. It is used for the HETDEX project that I have been involved with in the past.

Hobby Eberly 10-m telescope at McDonald Observatory

Me on top of the 82" observatory, with the 107" to the right and the HET on the back.

Sofía on top of the 82-inch telescope with the 107
														inch and the HET 10-m telescopes in the background

The 36" telescope is also widely used by undergradutes when we visit the observatory as part of the UT Astronomy Students Association ASA.

A photo of the UT Astronomy Students Association
																			 in front of the 36-inch telescope at McDonald Observatory

The Fank N. Bash Visitor Center. They have other telescopes for outreach but you can also book a guided tour to the telescopes on Mt. Locke!

The Fank N. Bash Visitor Center near McDonald Observatory

Me helping at the Visitor Center where we talked to the general public and show them a few planets with telescopes.

Sofía at an outreach event in the Visitor Center getting
																						ready to show the stars and planets through telescopes to the public

The general lanscape of West Texas as seen from the observatory.

A panoramic picture of West Texas taken from the HET 10-m telescope

Telescopes in Colombia

The National Astronomical Observatory (OAN) was the first observatory built in America in 1803. Actually, the independence of the Viceroyalty of New Granada from the Spanish Crown was planned in this building and took place on July 20, 1810.

Since The Independence, the observatory was abandoned or worked as a prison. In 1891, Julio Garavito became Colombia's first Professor in Mathematics, and Director of the OAN. Here, he studied the Moon's movement and discovered a crater on its Dark Side. Sadly, the observatory was inactive for much of the XX Century until it became part of the National University of Colombia - Bogotá. (UNC)

The UNC left the OAN as a historical site and built a modern observatory but on its university grounds in 1952. The UNC was the first university to begin a Master's Degree in Astronomy, and recently inagurated in 2017 the first Ph.D. Astronomy Program of the country. Colombia is indeed an emerging country in Astronomy and we are working hard to give more opportunities to the new generations!

Historical Headquarters of the OAN

Historical Headquarters of the National Astronomy Observatory of Colombia (OAN)

Academic Headquarters of the OAN with Dr. Santiago Vargas, Sofía Rojas, Cristian Góez, Dr. Leonardo Castañeda.

Sofía and professors from the National University in front of the
											OAN Academic Headquarters

Tatacoa Desert Observatory in Huila.
Guaranteed best skies of Colombia.

The old atacoa Desert Observatory in Huila, Colombia