Friday, September 29, 2017 found us at anchor off Rábida, the smallest island on our itinerary. It is known for its red sand beaches. We started with a nature walk. There were starfish washed up on shore:
Starfish
Pretty morning glories:
Morning Glory
Quite a few lava lizards:
Lava Lizard
Lava Lizard
And we got our best look at the Galápagos Flycatcher:
Galápagos Flycatcher
Galápagos Flycatcher
Galápagos Flycatcher
Galápagos Flycatcher
Galápagos Flycatcher
We made our way to the top of a hill where we took a group portrait:
On 1 April 2026, the Artemis II mission launched for a crewed trip around the Moon. I had heard that, in the Apollo missions, the spaceships were viewed and/or imaged from several ground-based telescopes, and I wanted to try it myself. The first task was to figure out where, exactly, the capsule would be. After figuring out that the "Integrity" would rise from my location around midnight, and after verifying that I might have some clear weather, I used the JPL Horizons database to generate an ephemeris of the right ascension/declination coordinates as seen from my location: I saved it as a CSV and imported it into a spreadsheet, where I used a table of predicted brightness values based on distance to figure out if it would *really* be visible: I also imported these coordinates into Stellarium so I could visualize their actual location in the sky at the various times. I did this by creating a Javascript script that I then pasted into the Stellarium script editor: The m...
I got two GoPro Hero3 Black cameras and am planning a panoramic project with them. However, to do the project correctly and accurately, I need a good read on their field-of-view. So, I set up a tripod and a grid and a tape measure, and took a few photos. Here they are, desaturated and contrast-enhanced, with central red dots and some annotations. First, measuring the diagonal FOV: Next, the horizontal FOV: Finally, the vertical FOV: The front of the camera lens was almost exactly 17 inches from the grid. The camera body started about 17.25 inches from the grid. Assuming the sensor is embedded some distance into the body, I used an estimated field-to-sensor distance of 17.5 inches. This yields the following field-of-view, in degrees: Diagonal: 146 Horizontal: 121 Vertical: 93 Doing a little interval math on the field-to-sensor distance shows these angles are accurate to about plus or minus 1.5 degrees. Int...
A few years ago, I converted various planet maps to icosahedral models . You can print these out, cut along the solid lines, fold along the dotted lines, and have a nice icosahedron to play with. Since then, two more robot spacecraft have created global maps of planetary bodies. Most recently, the New Horizons spacecraft flew past Pluto. Here is an icosahedral projection of the data we have so far: Also fairly recently, the Dawn spacecraft has orbited both Vesta and Ceres, two of the largest asteroids (or "dwarf planets" as the new nomenclature has it) in the Solar System. Here are icosahedral projections of those two. First, Vesta: Next, Ceres - note the mysterious white spots toward the upper right: All of the data used to create these projections was taken from Steve Albers' Planetary Maps Page , which I highly recommend. Edit: A PDF file of helpful hints on assembling these can be found here .
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