Under the Stars of Cerro Tololo: Night 2

Night Two on Cerro Tololo was tremendous. We started out the evening with a viewing of the sunset from the edge of the mountain top just outside the central gathering place: the cafeteria 😉  Food on the mountain, by the way, is delicious, plentiful and healthy. We had hoped to catch the green flash, but we had some low clouds floating in the western horizon. No flash, just gorgeous views of the mountains as the landscape turned red.

CTIO Night 2: Sunset Panorama

CTIO Night 2: Sunset Panorama

CTIO Night 2: Sunset

CTIO Night 2: Sunset

Once the sun had set completely, the stars came out rapidly. The moon was in a waxing gibbous phase, which meant that much of the night would be illuminated quite well: no need for flashlights to get around the mountain until the moon set. Here is a 30 second exposure of the Milky Way, which was VERY visible, while the moon was still high in the sky. Imager: Nikon D810a 16mm f/2.8 fisheye 30 seconds.

CTIO Night 2: Milky Way with Moon

CTIO Night 2: Milky Way with Moon

It is pretty exciting to be seeing the Milky Way so clearly even with a gibbous moon high in the sky. The transparency at CTIO is tremendous with some of the best seeing conditions I have ever witnessed.  One very obvious feature of the Cerro Tololo sky is that there is no scintillation. Stars do not twinkle! They are steady and just hang in the sky. If this was the sky with the moon above the horizon, what would it look like once the moon had set after 3:30am or so?  I went to bed and set the alarm for 3am. That was a very good decision!

As the alarm went off, I was pretty sleepy, but very excited by the prospect of getting some stunning images of the sky. Stepping out of the dorm room onto the sandy pathway, it was more than obvious that the moon had set for our side of the mountain. Shadows of Cerro Tololo were being cast by the moon onto the eastern peaks. The snow line was still clearly visible, but that shadow was rising rapidly as the moon went further below the horizon. Grabbing the camera and tripod, I made my way outside. Several of us gathered for the stunning view: a Milky Way from horizon to horizon, with dark lanes, bright nebulae, clusters galore, and color! It is very difficult to convey just what the scene looked like. There were so many stars that constellations were sometimes impossible to identify, giving strong evidence to the native constellations, the dark regions of the Milky Way become the Llama, the Toad, the Serpent, the Shepherd, the Fox, all became visible as dark shadows over the blazing Milky Way.

CTIO Night 2: Milky Way

CTIO Night 2: Milky Way. A single 30 second exposure. D810a 16mm fisheye f/2.8

CTIO Night 2: The Milky Way with SMC and LMC

CTIO Night 2: The Milky Way with SMC and LMC. A single 30 second exposure 16mm f/2.8 D810a.

About johnb

- Director of Grainger Observatory, Phillips Exeter Academy. - Variable-star-crazed astronomer, but have done research in other areas. - Drummer, archer, pilot, chef, friend, pet owner, husband, father, Train-nut.
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