Showing posts from January, 2022

Detecting the Hunga Tonga-Hunga Ha'apai eruption with a barometer

Here's a bit of fun around the Hunga Tonga-Hunga Ha'apai eruption. We all know about the tsunami alerts and the distance the sound was heard from. But did you know that domestic meteorological instruments in Perth were able to detect the eruption? Here is a shot of my personal weather station's history for yesterday with some very rough annotations. The eruption was at about 12:10 AWST, and just over six hours later, my barometer detected the shockwave. About an hour after that, it registered the rebound shock. This has been confirmed by multiple other instruments across WA, and you can even trace the movement of the shockwave across the country. Here is a snip from the station at Condingup. As you can see, the pressure shockwave hit there about 30 minutes earlier.  Condingup is about 600km East of Perth, so we know the shockwave travelled at about 1200km/h. Tonga is about 7000km from Perth, and the shockwave hit at about 18:25 AWST - about 6 hours and 15 minutes after the

SFF Music Video of the Week - #125

Well we've got a fun one this week! Banjo spaceships, alien abductions, and a country cover of a classic rock anthem. Offering up a counterpoint to my belief that almost any song can sound good when played by the right people (see - " ...Baby One More Time" by Ahmet and Dweezil Zappa ), this shows that some songs cannot be harmed by the style in which they are played. So sit back and relax (or not) as The Dead South cover "People Are Strange", from 2021.

Life of prepared cyanotype papers

Common wisdom says to use traditional yellow-type paper as soon as possible after it has been prepared. And certainly, you will get the best results from that. However, do not be dissuaded from using older paper. Last April I ran a workshop on building cyanotype cameras, and I had a bunch of kits left over. Today I pulled out some of the papers, and did some contact print test exposures. Pleasingly, despite being quite discoloured when unexposed, they exposed perfectly well, even with a very low contrast negative. So even after nine months, a well prepared paper with is still perfectly usable! This makes stockpiling for trips a much more plausible thing! On the left is a 20 minute exposure, and 10 minute on the right. The negative is notably low-contrast. As you can see, fully exposed areas still give excellent density, and the unexposed areas have nearly washed clean, with only a little residual staining.

SFF music video of the week - 124

There's been a bit of a hiatus, but I'm back! This time I go all the way back to 1933, and the legendary Fleischer Studios. Fleischer were the creators of the infamous Betty Boop and many others, and were the original animators of both Popeye and Superman. Here we have them taking on Snow White in their distinctive style, accompanied by jazz legend Cal Calloway.  Enjoy "St James Infirmary Blues" by Cal Calloway from 1933.

In-camera Cyanotype exposure calculator

 Ilford/Harman do a wonderful little print-at-home dial calculator for pinhole cameras - but it also covers the range of f/ stops for more conventional cameras.  After some playing around, I have found that it can be adapted to cyanotype as well. 1/ On the ISO (middle) disk, locate the ISO .375 entry. Directly opposite it, write in "Cyanotype". 2/ On the Lighting/Shutter disk (the largest, bottom disk), write in "UV12" between the "->" and the full sun. Then "UV6" between the sun and the "19", and "UV3" between the 19 and the clouded sun.UV 15, for folks in places like Perth or Broome, roughly lines up with the ">" itself. That's it! At UV12, and f/1, an exposure time of 30 minutes is given as the result, which is just about spot on for a properly exposed image after washing. The same lens at UV6 gives a 1 hour exposure - which is correct, given the UV Level scale is linear.  Have fun!

Homebrew Solargraph Can Camera Refinement

 The classic beer can solargraph camera is easy to make - as you can see from Justin Quinnell's video . Justin's design is simple and safe for kiddies. Unlike this one , although it has the advantage of being significantly more waterproof. But what if there was a better way? A way to get near-complete waterproofing (except for the pinhole), and still have the build be kiddie-safe? Enter a construction and roofing repair product called Flashing Tape - this is heavy-duty tape with an aluminium backing - making it completely light-proof. The adhesive is thick and conformal, meaning that you can get a complete seal with it.  This means that you can use Justin's tin-opening method (which leaves no sharp edges), and still get a complete water-and-lightproof seal.  I use two strips of 50mm tape at right angles to ensure a complete seal, but you could also use a single strip of the 75mm tape.  The only down-side is that you will need to use a knife to cut the foil off when you are