Here are some more things you can do with your RTL-SDR after the first 50:

Meteor weather satellite reception (Russian counterpart of the NOAA satellites, but digital, so higher res and in color)

Digital Radio Mondiale -- digital radio but for shortwave

Analog TV -- if you're in an area that still broadcasts this (unlikely), you can receive a black & white picture and closed captioning. If no OTA broadcasts remain, you can use the analog output of a VCR or DVD player

GPS -- rtlsdr is capable of decoding GPS, Galileo, and BeiDou! (Likely not GLONASS since each satellite uses a separate frequency, spreading the signal beyond the sdr's bandwidth)

Hidden secondary audio broadcasts inside FM radio (like the stereo audio hack, but using higher frequencies in the demodulated stream)

Brazilian outlaws and UHF pirates using open repeaters on US military satellites launched in the 70s

TEMPEST / "Van Eck phreaking" where you can remotely read a nearby screen due to leakage from the monitor or video cabling

Instrument landing system -- if you're near an airport you can tune to a runway's ILS frequency and see the signal change as you move from the left side of the runway to the right

Infrared remotes -- stick an IR photodiode in the antenna port and you can demodulate codes from remote controls

Passive radar -- Tune into a very narrowband signal like a VOR or ATSC pilot signal, set your decimation extremely high (i.e., trading bandwidth for dynamic range) and you can see nearby planes in the area from their doppler-shifted reflections of the main signal

Specifically mine deals with what you'd hit looking across the ocean from a coast. I had long wanted to make mine an interactive app but could never fully motivate myself to do it, so congrats for shipping.

(The standard US outlet "type B" is a NEMA 5-15)

I wrote my own decoder in python (nowhere near realtime) because at the time I couldn't find one that handled color. The deep dive on the design tradeoffs and signal processing hacks for NTSC was fascinating.

A few of my exploits below:

Full-frame decode of VHS w/ closed captioning: https://mrgris.com/a/ntsc-cc.mp4

Faithful reproduction of analog artifacts: https://mrgris.com/a/colorbars_slow.gif

Analog scrambling: https://www.youtube.com/watch?v=qceZgxSBHwo

Inject custom captions (it supports color!): https://mrgris.com/a/thanks.mp4

Sad that these signals are gone now... would have loved to play around with SAP/MTS, teletext, C-band...

I remember becoming disillusioned that the netbook branding pivoted to "cheap" rather than "compact". The 9" series was quickly abandoned, with much more expensive 10" models becoming standard. An "almost laptop"-sized laptop for "almost laptop" prices wasn't really compelling. The 901 was adorably small and only cost $400 iirc.

The path of the sun's annual motion relative to the stars is determined solely by my physical progress in orbit around the sun. A planet's axial tilt only changes the 'direction' I'm looking in and thus the reference point of my celestial coordinate system. The sun's path will always be a great circle on that celestial sphere (and always the same relative to the fixed background stars) regardless of which reference frame I choose. I think this is enough to surmise that the sun's angular speed on the celestial sphere is constant regardless of axial tilt (assuming a perfectly circular orbit).

Taken to an extreme, imagine a planet with 90° tilt -- the sun would move vertically and pass directly over the pole, making a constant 'horizontal' motion literally impossible.

I'm not sure what your tidally locked example is meant to demonstrate, since that's literally what the analemma is -- the path the sun would make in the sky once you subtract a planet's local axial rotation, i.e., tidally locking it to the orbital parent.

This is because the sun on an axial-tilted plane 'lags behind' then 'catches up' to the ideal 0-tilt sun over the course of the year. At the equinoxes, the sun's motion has a significant vertical component. Therefore, it's horizontal speed is slower than an untilted sun (both suns still travel through the sky at the same speed of 360/365 degrees per day), so it will lose ground and drift back. At the solstices, the sun moves horizontally, but at an higher latitude (equal to Earth's axial tilt) on the celestial sphere, covering more degrees of longitude for the same speed than the ideal sun moving along the equator, hence making up the lost ground. This variation in horizontal speed throughout the year creates the figure-8.