Knowledgebase: General ALMA Queries
How close can ALMA observe to the Sun?
Posted by Tony Remijan, Last modified by Fumi Egusa on 16 March 2017 04:15 AM
|ALMA can actually point at the Sun (solar observations are available from Cycle 4). Small grooves or etchings in the antenna surface are designed to ensure that sunlight is not reflected to the secondary subreflector. However, detectable solar emission is seen in the antenna sidelobes up to several degrees away from the Sun. So, if the target is not the Sun itself, it is not advisable to point closer to the Sun than a couple of primary beamwidths from the solar photosphere to avoid a large amount of contamination in the observations.|