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Headshot of Emily Lakdawalla

Approaching Neptune

Posted by Emily Lakdawalla

11-03-2016 12:17 CST

Topics: amateur image processing, Voyager 1 and 2, Neptune, animation

A couple of days ago, a scientist friend asked me if I knew of modern reprocessed versions of the movies that the Voyager spacecraft made as they approached Saturn, Uranus, or Neptune. I pointed them to a terrific Saturn approach movie, but couldn't locate Uranus or Neptune ones, so I turned to the amateur image processing community at to ask if anyone there had worked on this problem. It turns out that Ian Regan had, and a few days later Regan shared this "rough draft" of a Neptune approach movie. It's going to take much more work to turn it into a color movie, but I think it is spectacular as is, and am glad to share it here:

NASA / JPL / Ian Regan

Approaching Neptune (video)
Voyager 2 flew past Neptune on August 25, 1989. Here, Ian Regan has taken a long sequence of Neptune images shot through many different filters in July and August 1989, as Voyager 2 approached. Regan aligned them to make a rough draft of a movie of the spinning planet. It will take much more work to generate color frames from the images. Voyager 2 was relaying the images to Earth as it was taking them, so its frame rate was limited by how fast it could send each image: images are separated in time by about 5 minutes. There were gaps in imaging as Voyager 2 turned its camera to photograph other features in the Neptune system (rings and moons).
See other posts from March 2016


Or read more blog entries about: amateur image processing, Voyager 1 and 2, Neptune, animation


John: 03/12/2016 08:47 CST

Hi Emily. I'm puzzled.Perhaps you can help?. This excellent Neptune approach movie (Reagan) gives the impression that all the dark spots and white clouds move across the face of Neptune left to right. I have a similar approach movie produced by Nasa/JPL where the dark spot moves right to left but the lower white cloud nicknamed "the scooter" moves across the planet left to right! One or other movie gives a misleading impression. Which should I trust? Another Nasa/JPL "Slug Movie" computer generated from above the pole clearly shows spot and cloud rotating clockwise and counter clockwise at the same time. In the interest of scientific authenticity how can we get this point across. Thankyou for you excellent blog - as always .

Yorin: 03/12/2016 05:43 CST

John, is the movie you've seen something like this ? The video made by Ian Regan shows Neptune rotating, while parts of that Youtube video are made of pictures that all show the same side of neptune (each picture being taken after a full rotation, leaving out all the pictures in between). It's not a question of which one of these you should trust. They are both true, but made with different intent, one of them showing the planet's rotation, the other showing the atmospheric movements once the rotation is cancelled out.

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