Roof now has 21cm telescope on it as well

Gary Atkins and Marcus Leech moved the 21cm dish “up top” today, so that it can join the pulsar antenna.

We used a rope and brute force. This won’t work for our 1.2m dishes and their mount pods–not without a hoist of some sort.

The next antennae to go “up top” will likely be our UHF interferometer antennae, probably spaced about 30m apart or more.

Pulsar monitor undergoing overnight checkout

The pulsar antenna is now plugged into the pulsar receiver system, which consists of a pair of AirSpy SDR receivers, fed with a high-quality 10MHz OCXO timebase.

We’re running a pulsar-specific flow-graph, written by Marcus Leech, and using Gnu Radio underneath.

There are many unknowns–we don’t know if the ambient noise level is low enough without aggressive filtering, we don’t know if our antenna effective aperture is quite up to the task. This will be a useful test, but a negative result cannot be interpreted to mean “won’t work”.

Live data now available

Our first live data feed is now up and running, showing the neutral hydrogen spectrum as seen by our 21cm telescope, aimed at a declination of +40 degrees. This will show interstellar neutral hydrogen twice a day, for a couple of hours each time, when the galactic plane passes through the main beam of the antenna.

Check out our “Live Data” page for information.

Pulsar antenna mounts built, and antenna test-fit

Finished building the two “stands” for the pulsar antenna, which is a stack of garden-variety 4-bay HDTV antennae. This arrangement will give us an asymmetric beam, with a roughly 2:1 ratio, with the declination axis having a narrower angle than the right-ascension axis, somewhat like an ellipse.

This asymmetry will allow us to “see” the target pulsar for long enough to integrate the pulses synchronously for an extended period, without having to move the antenna at all. This lowers telescope complexity enormously, but compromises on sensitivity. We may add a 2nd “stack” of 3 4-bay antenna if this proves to be insufficiently sensitive.

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