Posted on 01/09/2014 by emily
Make a NAVCAM mosaic
Today’s four-image NAVCAM montage comprises images taken on 31 August from a distance of 61 km from comet 67P/C-G.
NAVCAM image sequences are now being taken as small 2 x 2 rasters, such that roughly one quarter of the comet is seen in the corner of each of the four images. The four images are taken over an approximately 20 minute period, meaning that there is some motion of the spacecraft and rotation of the comet between the images. As a result, making a clean mosaic out of the four images is not simple.
Thus, for the purpose of this montage, the four images are shown separated by black borders. There is some overlap between adjacent frames, so that some features appear in more than one image (see CometWatch update post for more about the reasons why NAVCAM images are being taken this way).
The images have been cleaned to remove the more obvious bad ‘pixel pairs’ and cosmic ray artefacts, intensities have been scaled to show a wide range of features, and the montage has been cropped to remove most of the black space around the comet. The dark feature in the centre is an imaging artefact.
In addition, we are also providing the individual JPEGs of the four full-frame ‘corners’ (click each image below for the full 1024 x 1024 frames), and warmly invite you to create your own mosaics and share them with us. You are welcome to post them on your personal profiles with the ESA/Rosetta/NAVCAM credit line, and share a link to your work in the comments box below, so that we have the possibility to follow up with you and eventually post your efforts on this blog.
We look forward to seeing what you come up with!