Step by step

STEP 1

Your lens size is determined by the scene you want to image. Here, it’s either Mercury and the Pleiades, or Mercury, Aldebaran, the Hyades and the Pleiades. For non-full frame cameras select a 125mm lens for the narrower scene, or a 70mm for the wider one. For a full frame DSLR, the lens sizes are 200mm or 110mm.

STEP 2

Find a location with a flat horizon from west through to northwest. If you’re feeling adventurous a well-placed tree or building could be used to add drama to the shot, but be sure the feature doesn’t cover any of your targets. In the run up to your attempt a test shot of the Pleiades and Hyades as they approach setting can be useful.

STEP 3

Monitor the weather forecast and make sure your kit is ready for quick deployment should conditions be favourable. Venus is an excellent focus object visible before the sky gets dark enough to see the Pleiades.

Next, set your camera to manual focus, pre-focus on Venus and carefully apply a piece of low-tack electrical tape around the focus ring to hold focus for several evenings.

STEP 4

Set the camera’s ISO low, somewhere between 200–800. If using a static tripod, open the lens then close it by a stop or two to limit distortion. Experiment with exposure to give a bright but not overexposed background sky. If your results are too dark, up the ISO slowly. Remember, this is twilight, so it will darken over time.

STEP 5

If using a polar-aligned tracking mount, use a low to medium ISO and set the f-stop number to a mid-range value, say f/11-f/16. Experiment with a multi-second exposure. Again, don’t worry if the sky appears too light, just make sure it doesn’t over-expose. Check the image histogram to ensure no clipping has occurred.

STEP 6

Open the final image in a photo editing program. Copy the base layer, keeping the original for backup. With the copied layer, open ‘Curves’. Place an anchor where the default curve-line passed through the main histogram graph. Drag the curve to the left down so an ‘S’ shape is created. Tweak the S-curve as needed.