A Personal Note


Mrs. Hoge had her first session of chemotherapy today and is doing very well. She is very grateful for your prayers and good wishes.

Because of her illness, I am taking a pass on most of CPAC this year, but I will be attending BlogBash this evening. The press of the day’s events has cut into the time available for blogging. As a result, the three posts that would normally appear around midnight, Quote of the Day, TKPOD, and AYPWIP, will get tonight off. Normal blogging should resume with the Internet Astronomer post tomorrow morning.

A Decade of Swift


The Swift satellite has been on orbit for ten years. It was the first  project I worked on at Goddard Space Flight Center. I designed and tested the ultra-low-noise power regulator assemblies that run the detector assemblies in the Burst Alert Telescope. I did the circuit design for the variable output high-voltage regulators that provide bias power to the sensors in the BAT detector assemblies. The BAT sensor array is held at a constant temperature (298 K, ± 0.5 K). I designed the pulse-width modulation regulators used in the thermal control system. The same type of PWM is used in the thermal controls for the star trackers which are a part of the satellite’s navigation system. Given that the mission design life was two years, it’s nice to see that my first bits of work are holding up.

Video Credit: NASA

In Answer to Some Questions


A former amateur investigative reporter who is now trying to work the religion page has asked several questions over the last day. Here is my answer:

I find your lack of faith disturbing.

UPDATE—If an intrepid religious report knew his stuff and he wanted to question the bona fides of someone serving as a treasurer of a religious fund, he would allude to John 12:4-6. Of course, that would require a working knowledge of his subject matter.

The Perseus Dark Matter Matter


Video Credit: NASA

Personal Note—I contributed to the design of the cryogenic temperature control system being used to cool the detector array in the Soft X-ray Spectrometer that will fly on Astro-H. The system is capable of holding the detector array at 0.05° above absolute zero with a stability better than ±0.000001°.

When an individual x-ray photon strikes one of the pixels in the SXS detector, the energy raises its temperature slightly which changes the resistance of the cell—the more energetic the photon, the greater the change. The low operating temperature and the tight regulation are necessary to make lower energy x-rays detectable and reduce system noise.

Field Day So Far


FD 2014-1The Carroll County Amateur Radio Club is operating a multi-transmitter Field Day site. We have two stations operating phone (ham talk for “voice”), one operating CW (ham talk for “Morse code”), one operating digital modes (ham talk for “text”), and one operating via amateur radio satellites.

The picture at the left shows Curt WB8YYY operating my low-powered CW rig. His left hand is adjusting the tuning knob. The laptop is used to log the contacts with other stations and to log the radio settings. His telegraph key is just out of the frame on the right.

Some years, the club goes all out to score the most points we can. This year, Field Day is laid back. At around 6:30 this evening, we stopped operating and had a picnic. It was a beautiful day to be outdoors.