The HP-16C programmer’s calculator.

The 12C financial calculator gets all of the love when it comes to HP’s line of reverse polish calculators (it’s the only one I still see in stores), but the 16C was by far my favorite. It was the only place that I could do stuff that my TI-89 couldn’t, most specifically performing all of your operations in any base you want (helpful because I used to work almost exclusively with A/D converters that would give unsigned 12-bit integers for their measurements).

Some of the other features, most of which I haven’t seen on another calculator:

• Integer and floating point math.
• Shift functions: Left and right, arithmetic and non.
• Rotate functions: Rotate a single position or N positions left or right, through carry or not.
• Left justify the bits of a word.
• Masking: Create masks to mask left or right N bits.
• #B: returned number of bits set in a word
• Multiply/Divide: Provided functions for multiplying single precision numbers into single precision or double precision results. Likewise, allowed single or double precision dividends.
• Bitwise Logic: and, or, not, xor
• Bit setting and testing
• Flag setting and testing: (user flags and overflow/carry)

There’s a great iPhone app emulator called Calc 16Cx ($1), and one called ClassicRPN ($15) that does the 11, 12, 15 and 16 models.

usagov:

This video shows the the flowing ribbons and rays of the aurora australis, or “southern lights,” filmed by astronauts on the International Space Station (ISS) while passing over the Indian Ocean on September 17. This was filmed while ISS passed from south of Madagascar to just north of Australia between 17:22 and 17:45 Universal Time. Solar panels and other sections of the ISS fill some of the upper right side of the frame.

Learn more about this video and auroras from NASA’s Earth Observatory.

(via david)

jtotheizzoe:

Humans fire laser to sky, sky laughs, responds with lightning

(They were actually firing a kind of “guide star” that is used to target and correct ground-based telescopes when this shot happened. Nature is still not impressed)

(via Short Sharp Science)

amazing.

(via nprfreshair)