Site Nightingale is located in a small crater encompassed by a larger crater (with a 230 ft, or 70 m, radius) near Bennu’s north pole. Nightingale has multiple areas that are being evaluated for sample collection. The first, with a 16 ft (5 m) radius, is located in the northeast region of the crater. The second area, also with a 16 ft (5 m) radius, is located slightly west of the crater’s center. The third area has a 26 ft (8 m) radius, and reaches from the crater’s northern rim to its center. The fourth and largest area, with a 33 ft (10 m) radius, encompasses nearly the entire crater. Nightingale contains mostly fine-grained, dark material and it has the lowest albedo, or reflection, and the lowest surface temperature of the four candidate sites. Nightingale’s regolith also has the highest color variation, which suggests the presence of diverse materials.
This set of stereoscopic images provides a 3D view of site Nightingale, located in Bennu’s southern hemisphere. The two images in this stereo pair were taken from slightly different viewpoints, with one of the images meant for the left eye and the other for the right. The two images are then combined by the brain to give the perception of depth. To see the pair in 3D, download the image and view it through a stereoscope. The cropped and processed images were obtained on March 21, 2019, by the PolyCam camera during Flyby 3 of the mission’s Detailed Survey: Baseball Diamond phase.
This anaglyph of site Nightingale was made from the above stereo pair. Each stereoscopic image was encoded using filters of chromatically opposite colors—one made with red and the other with cyan. When viewed through color-coded anaglyph glasses, each of the two images reaches the eye it’s intended for, and a 3D image is produced. Anaglyphs are helpful for selecting a sample collection site because they allow the team to intuitively understand the three-dimensional structure of objects like boulders and craters.
Boulder Count Maps
These Boulder Maps for site Nightingale detail the number and location of boulders present within the region. Because Nightingale has several possible sampling regions, a boulder count map was produced for each of these regions. The boulders are counted by the human eye, using a single image at a time. Many of these boulder counts were made by members of the public who participated in the CosmoQuest Bennu Mappers citizen science campaign. The boulder counter marks each boulder by the longest axis (point to point) in order to calculate maximum boulder size. Rocks that are 10-21 cm are marked in yellow. Anything larger than 21 cm is marked in red. Rocks and debris that are ingested by the spacecraft’s Touch-and-Go Sample Mechanism (TAGSAM) head must be no more than 2.5 cm wide.
The OSIRIS-REx spacecraft is about the size of a 15-passenger van, so for a familiar perspective, this is site Nightingale superimposed over a standard parking lot. Nightingale, which lies within the white circle, covers roughly 6 parking spaces. The width of each parking space is 9 ft (2.7 m).
Sample Site Location