Harvest moon over the Ottawa River

Jim Elder

Ottawa, Canada


Sand & Dunes


Aeolian dunes and sandstone: Overview (intro, including animations)
Strata dip and thickness: True and apparent

Observations & Interpretations

Grainflow/avalanching, vortices, grainfall at Coral Pink Sand Dunes State Park, USA (videos)
Grainflow/avalanching (video)
Sand micrographs (photos of sand grains); stereogram of Navajo sand grains
Thin sections of grainflow with pinstripes
Air flow in the lee of a dune (recirculation cell)
Cornice deposit (grainfall lee of the brink)
Grainflow (slipface avalanche deposits)
Cross-sectional profile of some avalanche tongues/troughs

Coral Pink Dunes State Park, Utah, USA:

Dune migration (analysis of Google Earth imagery)
Stoss slope trenches (internal dune structure)

Serial sections (image stacks for 3D reconstructions) of rock samples:

Kanab Goldenstone (Triassic Shinarump Formation; Utah USA)
Iron-oxide concretion A (Jurassic Navajo Sandstone; Utah USA)
Iron-oxide concretion B (Jurassic Navajo Sandstone; Utah USA)

Numerical Models

Dune field morphology (model of migrating bedforms)
Model of stratigraphic bounding surfaces produced by migrating bedforms (stratigraphy)
Sampling dune sand (effect of sampling on grain-size distribution results)


Making pinstripe laminae visible in dry sand (a refinement of Bagnold's water seep method)
Measuring cross-sectional profiles of dune features (using the shadow of a straight-edge)
Detecting subsurface slipface shear (using a sand column of contrasting colour)
Making air flow visible (using simple streamers)
Making sand flow visible using an adapted Hele-Shaw cell
Measuring dip (eg., angle of repose)
Photographic reference scale (for scale, colour, and perspective)
Protecting photographic gear from blowing sand
Enhancing low-contrast photos (post-processing to improve visibility)
Serial sectioning to obtain images for 3D reconstruction (using a rock saw)
Particle analysis: Obtaining representative subsamples (spinning riffler)


2010 Dec Lizards of southeast Utah
2008 May Ravens in Aerobatic Flight
2008 Jan Bentonite (time-lapse photography of drying bentonite)
2005 Mar Basque Sheepherder Inscriptions
2004 Dec Multi-angle “3D” Photographs of Some Utah Landscapes (Escalante Canyon, The Thumb)
2004 Apr Observations of an Active Dune (including a video during a sandstorm)
2003 Mar A Deformation Feature in Grand Gulch

Photography & Photomicrography

2017 Jan LoCAte Focus Analyser (tool to measure focus and longitudinal chromatic aberration)
2017 Jan PGM File Viewer (viewer for PGM files made from RAW photos)
2010 Nov Adapters for afocal optical coupling (photos through microscopes, telescopes, binoculars)
2010 Nov Measuring resolution (eg., of a microscope or camera), using Airy pattern, FFT, MTF50
2010 Nov Review: MicroscopeNet V434B stereomicroscope
2008 Jan Review: Nikon Coolscan V slide scanner, VueScan software
2007 Nov Photographic Reference Scale
2006 Oct Comparison of some Ottawa photofinishers (4x6 prints)
2004 Oct Notes on making multi-angle '3D' photographs (including javascript for Photoshop, web display)
2004 Jul Dynamic range of photographs


2015 Oct Time-lapse video of a dehydrating Magnolia Biondii seed pod
2014 Dec Rock released into near-Earth orbit
2011 Dec Review: Computer USB Headsets
2007 Sep Six Steps to Survival (1955, 'How to survive nuclear war'; US Civil Defense Authority)
2007 Jan Canoeing the Rideau Canal and Trent-Severn Waterway
2006 Dec Charts & Figures from "An Inconvenient Truth"
2006 Dec Emission Spectra of Some Compact Fluorescent Lamps (CFL Bulbs)
2006 Oct Power Consumption of Some Household Appliances
2005 Jan Hele-Shaw Cell: Avalanche Segregation and Stratification
2004 Aug Two Mile Time Machine (climate history deduced from Greenland ice cores)
2000 Oct Varietal Features of Wine (an analysis of wine reviews)