Updates to SCUBA-2 first light images

First-light test observations of Jupiter reveal three of the Galilean Moons.

Jupiter is used quite often during the early phases of commissioning for obvious reasons, primarily that it is very bright and so we can get to it and observe during the day as well as night. The image above shows an 850µm image of Jupiter obtained during initial pointing and focus tests. Out of interest, we ran the data through a point source matched filter and pushed the plotting levels down low. The result is shown in the figure above. Being so bright, Jupiter comes out as nonsense but we have detected three of the Galilean satellites! As this ephemerides shows, the fourth, Io, is just about hiding behind the face of Jupiter.

Purely out of interest, the images below show an improved reduction of that shown in a previous blog post following first light with the new arrays. They are from a quick map taken of the OMC-1 cloud, and I do mean quick, as the telescope was scanning at a speed of 600 arcsec per second!

Note that at the time, only three of the four arrays were available at 850µm.

Improved reduction of first light image of OMC-1. The half-degree field was scanned at 600 arcsec per second.

A signal-to-noise image of the OMC-1 map. Plotting scales are between -15 and +900.

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6 Responses to Updates to SCUBA-2 first light images

  1. Pingback: Comparing array performance : one year later « SCUBA-2 News Blog

  2. Wrilliam says:

    Dear Antonio, The detected Jupiter satellites are close to being in a row as expected. What are the other blobs disposed around Jupiter at about the same S/N as the detections/
    Wrilliam

    • Antonio says:

      Hi Wrilliam – those artifacts are a consequence of the optics of the telescope, and because Jupiter is so very bright they appear prominently in such images. If we hadn’t detected Callisto and Ganymede at the correct positions we wouldn’t have been able to claim Europa with any degree of confidence.

  3. Wrilliam says:

    Thanks for your prompt response, Antonio.
    I’m curious as the optical nature of the apparent point sources – are they apparent with images of Mars, which I imagine is more of a point source than Jupiter. They must be artifacts of the panel setting….

    Wrilliam

  4. Wrilliam says:

    Any more on the artifacts – I’m curious how they appear with a point source filter……

    Very nice result…..

  5. Antonio says:

    Hi – yes we do see the same effect with Mars – we clearly see the airy ring. Measuring and adjusting the dish surface is something that we have to do in the very near future for astronomical commissioning, when the beam shape becomes more of an important factor.

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