We changed the declination of the interferometer antennae to point at +41, and got several good transits of Cygnus A (3C405), shown below.
Our next target is Hercules A (3C348), at a declination of +5, currently transiting in the middle of the night for us, so no Sun problems.
Using CCERA’s “insanely small array” radio telescope, we have successfully completed a 4-day “study” of the extragalactic radio source Virgo A. Show below are both the complex-correlator outputs, and the brightness derivation. Virgo A, also known as M87, is a massive galaxy some 54 million light-years from earth. It plays host to a super-massive black hole at the center, which produces a super-luminal (apparently-faster-than-light) gas “jet” of ejected material.
Its radio flux at 611MHz (our observing frequency) is approximately 500 Jansky, or 5×10^-24 Watts/M^2/Hz of bandwidth. Since our antenna are roughly 1 M^2 in area, That means that we’re intercepting a few pico-watts of power from this source!
Our lab/office has successful moved downstairs, to Suite 104. We’re still working on bringing back some data services, like the 21cm spectrometer feed.
IN the last week, we’ve had success in making our UHF “pathfinder” interferometer operational, at a frequency of 611MHz, with a baseline of 33.5m. A “first light” interferogram from Virgo A is shown below. Virgo A, also known as M87, is a super massive elliptical galaxy roughly 54M light-years from earth. It is very luminous, making it easy to “see” with CCERA’s modest instrumentation.
We’re nearing completion of the move of our office/lab space one floor down, from suite 204 to suite 104. This was necessitated by some “reconfiguration” required by our landlord.
One side effect of this move is that we’ll not be providing the 21cm data products for a few days as we rebuild our IT environment.
The move *may* also have the desirable side-effect of reducing self-interference from our computers, since we’ll be both further away from the antenna, and also have another layer of *thick* concrete and terra-cotta block floor between our lab and the antennae on the roof.
We’ve re-jigged the pulsar array again, changing it from a 3 x 3 array to a 2 x 4 array. This geometry is much easier to manage, and it has allowed us to build a better reflector screen under the array, hopefully reducing the amount of ground radiation “seen” by the array elements.
We’ve been working to improve the functionality of the pulsar array in order to enhance the reliability and verifiability of ongoing observations of PSRB0329+54.
Gary Atkins and Marcus Leech re-engineered the pulsar array support structure, and have been working on adding a “fence” around the array, to exclude low-angle RFI, which is where most terrestrial interference will be coming from. More work needs to be done to extend the fence around the entire array, but the array is now better-balanced on the support structure.
In addition the front-end electronics have been replaced to improve up-front filtering, using a custom UHF filter provided by Jan Jency in Slovakia. Further versions of this filter will allow us to observe on any of the 3 radio astronomy frequencies in the North American UHF band, while suppressing others.
A peak inside the new front end shows a noise injector, and a new 1/4-wave filter/protector
The noise injector hasn’t been connected yet, but will allow us to do a quick “sanity test” of the entire pulsar system from the comfort of the lab.
Stay tuned 🙂 🙂
We’ve been working on improving EMI/RFI suppression of our own equipment, to improve the chances of confirming reception of pulsars, and radio astronomy in general.
We’ve added ferrite chokes to all computer cables, etc, and EVERY cable that goes across our bulkhead to the outside world has at least one ferrite choke on it.
We’re working on shielding our window, to reduce the area of radiation leakage from our own equipment to a minimum:
The existing bulkhead has had foil tape added to it, and one of the windows is completely covered with 6mm hardware cloth. The other windows will get a similar treatment.
The walls and ceiling are already fairly good from an RF leakage perspective–50cm concrete on the walls and roof deck, with both mesh and re-bar reinforcement. Given a randomly-chosen building, one couldnt’ ask for much better for doing sensitive radio receiving experiments. The office ceiling (which is dropped only about 20cm below the roof concrete deck) is made from interlocking steel tiles, locked into a steel rail system. Also an excellent serendipity for us.
We have had success in observing pulsar B0329+54 with our pulsar antenna, after making several adjustments both to the antenna structures, and the receiving software.
Here is an averaged, phase-centered, pulse profile, taken over three observing sessions from November 29 until Dec 1.
While it’s still *possible* that this is an RFI artifact, it becomes quickly decreasingly likely as we make more observations.
Marcus Leech went “up top” to make some elevation adjustments to the now-twice-the-size pulsar array,
and added a cross-brace to the “upper” side of the array to stiffen it.
There’s been a fair amount of RFI on the 611MHz radio-astronomy ‘window’, so we’re trying to track it down.
We’ve had a large early-season blizzard here for the last couple of days. Once it calmed down,
Marcus Leech took the opportunity to check on the equipment on the roof to make sure that it was
all still intact and working properly.
Everything was as it should be.