An overview of the Chandra mission and goals, Chandra's namesake, top 10 facts.
Classroom activities, printable materials, interactive games & more.
Overview of X-ray Astronomy and X-ray sources: black holes to galaxy clusters.
All Chandra images released to the public listed by date & by category
Current Chandra press releases, status reports, interviews & biographies.
A collection of multimedia, illustrations & animations, a glossary, FAQ & more.
A collection of illustrations, animations and video.
Chandra discoveries in an audio/video format.
Q&A: Chandra Mission

Q:
The X-ray image of Orion Nebula seems to have a large cross in its center, as if it was formed by 4 quadrants. Why is that?

A:
Orion Nebula
Orion Nebula
The cross in the image is an instrumental artifact due to the arrangement of the CCD chips in the imaging array of the ACIS detector. See http://chandra.harvard.edu/about/science_instruments2.html Some images do not show this effect because the image is entirely on one chip.


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