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Emily Lakdawalla • Sep 09, 2015

Dawn Ceres image bonanza: Grab your 3D glasses!

All the time that I've been distracted by the New Horizons mission at Pluto, the other dwarf planet mission has been steadily, methodically sharing dozens of images of brand-new sights of a previously unexplored icy world. I'm talking about the Dawn mission to Ceres, of course, and for the last couple of days I've been making up for lost time, completely buried in the Dawn Ceres images that have been released over the last few months in NASA's Planetary Photojournal.

Lately, they have begun to release images taken from their High-Altitude Mapping Orbit (HAMO), just 1470 kilometers above the surface of Ceres. These images are super cool but because I haven't been paying close attention to the mission (distracted by Pluto!) I found it difficult to orient myself and understand the scale of the features. So, like any good geologist, I made a context map.

I began with this great map of Ceres that includes labels for the first craters to be named:

Ceres map with nomenclature as of August 2015
Ceres map with nomenclature as of August 2015 This map of Ceres shows the dwarf planet's surface with features that have been named as of August 14, 2015. It is a simple cylindrical projection centered on 0 degrees east longitude. A full list of crater names on Ceres is available at the USGS Planetary Nomenclature Gazetteer.Image: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA

Named craters on this map include (from largest to smallest): Kerwan (284 km), Yalode (271 km), Urvara (163 km), Conirarya (136 km), Zadeni (129 km), Dantu (125 km), Ezinu (120 km), Kirnis (115 km), Occator (92 km), Toharu (88 km), Gaue (84 km), Nawish (79 km), Fejokoo (70 km), Rongo (68 km), Sintana (61 km), Asari (52 km), Haulani (32 km), and Kait (0.4 km). Tiny Kait marks Ceres' prime meridian.

Next, I looked at the more than 50 Survey Orbit images that have been released to date, and located their positions on the map. Now, if I were a Dawn researcher, I would have had access to mapping and geographic projection tools that could have automatically produced these footprints. I don't have access to either those tools or the necessary geometric information about image pointing, and anyway I don't need to be so accurate; I just need a pretty good location for the footprints so that I can identify which images overlap a feature that I'm interested in. So I just drew all the footprints as quadrilaterals. They're not perfectly accurate, but it's close enough for my needs. Once I had the Survey Orbit images located, I could dive in and locate the smaller footprints of the HAMO images -- with a lot of help from a similar map already produced by user "ZLD" at unmannedspaceflight.com. Et voilà:

Location Map for NASA-released Dawn images of Ceres
Location Map for NASA-released Dawn images of Ceres A quick-and-dirty location map for the images of Ceres released to date (September 9, 2015) at NASA's Planetary Photojournal. Blue and green footprints are for Survey orbit images, from an altitude of 4400 kilometers and a resolution of 410 meters per pixel; orange footprints are for High-Altitude Mapping Orbit images, from an altitude of 1470 kilometers and a resolution of 140 meters per pixel. Because all images are represented as quadrilaterals, locations are imprecise, particularly near the poles.Image: Basemap: ESA / DLR (Thomas Roatsch). Location map by Emily Lakdawalla.

While I was going through the images to make the map, I made lots of notes on Ceres' fascinating craters and other features. That discussion will have to wait for a later post. But one thing that this map enabled me to do more quickly was to identify locations that had been imaged twice from slightly different angles, allowing me to assemble 3D views. So grab your 3D glasses or cross your eyes or click the flicker-gif links and enjoy Ceres in 3D!

First, one of Ceres' splashier craters, Haulani:

Haulani crater, Ceres, in 3D
Haulani crater, Ceres, in 3D Haulani crater has long been known as "Spot 1," a bright spot on the surface of Ceres. Dawn revealed it to be an impact crater with bright ejecta. Haulani is 32 kilometers in diameter. This image is a combination of two Dawn images taken from Survey orbit on June 6 and 17, 2015.Image: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / Emily Lakdawalla

Here's another, as yet unnamed and much smaller splashy crater:

Oxo: A small, bright Cerean crater in 3D
Oxo: A small, bright Cerean crater in 3D A region in Ceres northern' latitudes contains a variety of craters including one small one with a very bright wall and a fainter splash of bright ejecta. North is to the right. It is a combination of two images taken on June 21 and 24, 2015, during the Survey phase of the Ceres mission. The image is about 270 kilometers wide by 240 tall. This crater has been named "Oxo."Image: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / Emily Lakdawalla

Urvara crater has quickly become one of my favorite regions on Ceres:

Urvara crater, Ceres, in 3D
Urvara crater, Ceres, in 3D Urvara is one of Ceres' larger and fresher craters, located adjacent to the large Yalode basin in Ceres' southern hemisphere. This anaglyph is composed of two images taken on June 9 and 25, 2015, during the Survey phase of Dawn's Ceres mission.Image: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / Emily Lakdawalla

But the spot with the best story to tell is this one, first noticed by some sharp-eyed folks at unmannedspaceflight.com, in the same images that contained the little unnamed splashy crater. In 3D you can really see the steepness of the crater wall, and the long runout of the landslide into the strangely hexagonal crater. (Ceres has a lot of those hexagonal craters.)

A landslide in Ceres' far north in 3D
A landslide in Ceres' far north in 3D Near Ceres' north pole, an asteroid crashed into the steep rim of a hexagonal-shaped crater, causing a large landslide. This 3D image has been rotated to place north down in order to make the lighting more intuitive, and upsized by a factor of two. The whole image is about 125 kilometers across. It is a combination of two images taken on June 21 and 24, 2015, during the Survey phase of the Ceres missionImage: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / Emily Lakdawalla

Now that I have my bearings on Ceres, I'll write more later about its strange landforms!

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