Ask Astro: When Curiosity takes a selfie, the place is the shaft that holds the digital camera?

Like once you take a selfie, Curiosity’s robotic arm is often not seen. Plus, these aren’t only one picture, however a composite of many.

Curiosity took this distinctive low-angle selfie shortly after drilling a rock known as Buckskin. A portion of the rover’s robotic arm is seen (of the three buildings that stick up from the highest of the rover, it’s the light-colored shaft within the center), however seems oddly lower off as a result of the remainder of the arm was not proven within the many photos used to create this mosaic. Credit score: NASA/JPL-Caltech/MSSS

When Curiosity takes a selfie, the place is the shaft that holds the digital camera? It’s by no means seen, just like the digital camera was positioned on a tripod and a timer set. Was it edited out?

Bob Discovered
Indian Harbour, Nova Scotia

To take a selfie (just like the one on pages 24–25 in our September 2022 concern), Curiosity makes use of the Mars Hand Lens Imager (MAHLI) digital camera on its multijointed robotic arm. The method is roughly the identical as when a human takes a selfie: Curiosity holds out its arm to snap the pic.

There are two explanation why the arm holding the digital camera isn’t seen. First, take into consideration how you’re taking a selfie with a telephone: You do precisely because the rover does, holding the digital camera out along with your arm prolonged. Your arm doesn’t seem within the selfie as a result of it’s outdoors the view of the lens (under or behind it). Equally, in lots of instances Curiosity’s arm is outdoors the sphere of view of the lens.

Admittedly, it’s a bit extra difficult for a rover to take a selfie than for a human, and this introduces the second motive why the arm will not be seen. For us people, selfies are a one-step course of: Snap a pic and we’re accomplished. However Curiosity’s digital camera can’t seize your entire rover in a single shot, even from the tip of its 7-foot-long (2.1 meters) arm. As an alternative, the rover should take dozens of photographs to suit its whole physique and background into the view. (This course of can take an hour or extra!)

To take action, the arm strikes across the rover to snap photos from many angles. In a few of these uncooked pictures, small parts of the arm could also be seen as a result of angle of the picture. Nevertheless, the rover takes so many photos that when NASA employees on Earth sew them collectively right into a closing, single selfie, they will select to make use of solely parts of the pictures that don’t embrace the arm. So sure, in instances the place bits of the arm would possibly seem within the picture, it has been selectively edited out of the ultimate end result.

Alison Klesman
Senior Editor