Archive for June, 2017

Nova Interruptus

June 23, 2017


I like to call this wide field (12 x 8 degrees) image, taken with a Canon 1100D (ISO 100, f2.0 100mm), nova interruptus. 🙂

The red arrow points to ASASSN-17gk (shown in inset), an 11th magnitude nova in Centaurus I observed on May 21. It also shows the trail left by a passenger airliner as it moved from top left to lower right during the one minute exposure, with tree-tops at bottom.

ASASSN-17gk visual band

The signal to noise ratio wasn’t high enough to get a good value and error for the nova’s magnitude via DSLR photometry, so I didn’t submit an observation. The light curve at left shows observations made by others and the polynomial fit below highlights the rough shape of the light curve.

ASASSN-17gk visual polyfit

Alto creator Charles P. Thacker dies

June 23, 2017

The influential American engineer Charles P. Thacker died on June 19, aged 74.

Thacker designed the Alto personal computer at Xerox PARC in the 1970s which influenced development of the Mac after Steve Jobs saw it during a visit to PARC.

He also contributed to the development of Ethernet, Tablet PCs, and laser printers.

The computer scientist Butler Lampson, one of Thacker’s colleagues at Xerox PARC and later at Microsoft has spoken about his ability to see what was important and his breadth of coverage:

He could do everything from circuit design all the way through hardware architecture and programming and user-interface design.

The Association for Computing Machinery and IEEE Computer Society recently honoured Charles P. Thacker with the Eckert-Mauchly Award.

HD 148703

June 12, 2017

A request for observations by astronomers at the University of Wroclaw in Poland was announced by AAVSO on June 8.

The bright (magnitude 4.23 V) long period eclipsing binary HD 148703 (aka N Sco, HR 6143) is expected to undergo primary and secondary eclipses on June 11 and 14 each lasting around 20 hours.

The brightness and requested precision of 0.01 or better makes this an ideal candidate for wide field DSLR photometry.

I’ve taken pre-eclipse images but cloud prevented me from imaging the primary eclipse. I’ll take further images over the next few days, hoping to record the secondary eclipse.