Methodology choices

July 2021

As outlined in the main rise/set page, one's image-taking approach needs to be different for each type of Moon rise/set. And it will change as the HDR technology advances. Other game-changers are: a second camera; video. The following mostly assumes one camera. With two cameras, you can choose to do 3D-stereo pair or split sky-foreground between the two.

"Day to Night" or "Night to Day"

These are real challenges for a time lapse because the Moon stays the same brightness (except in the lowest 2 degrees) while the background changes dramatically. I almost exclusively shoot 6-bracket exposure bursts with an intervalometer today, but for completeness here is the range of approaches:

1. go for single composites, allowing re-positioning, changing zoom

2. time lapse with single proper Moon exposure and using blended before/after foregrounds

3. multiple cameras. Allows more flexibility, but requires more work in post-processing to align the images. Stereophotomaker lets you generate 3D stereo pairs rather easily.

4. HDR blending a quintuplet of images. In winter I go for a sextuplet because the Moon is brighter higher up. So far EnfuseGUI does a nice job on individual frames. Note that the "Sat" parameter needs to be set to zero else it produces weird shading artifacts in the sky. If you find the Moon is still a little bleached, I batch create an ever shorter exposure, then enfuse the septuplet.

Clear Night

1. Basic composite is straightforward. Take foreground images before the Moon enters and after it leaves the frame. If you can, try and get some "dark steel blue" in the background sky to avoid it being plain black. In some cases this means arriving 30-60 minutes early or staying late to catch the twilight or even horizon reflection on the buildings.

2. Consider dynamic foreground issues

Partly Cloudy Night

This is a Goldilocks situation of just enough clouds providing "atmosphere" to the picture or time lapse but not too much to actually obscure the Moon. Some form of HDR is a must to capture the clouds and prevent the Moon from being blown out. EnfuseGUI does a good job on a bracketed set, but requires both an underexposed Moon and and overexposed foreground .

Crescent

This is pretty straightforward since one is going for earthshine and not worrying about the overexposed crescent. Generally a single exposure is fine to capture both earthshine and the city foreground. Thereafter, simple care to gradually ramp the exposure to keep the foreground nicely exposed. Earthshine of course depends on how cloudy it is on the sunlit portion of the Earth, but its visibility is crucially dependent on contrast against the sky. If the sky is bright and the Moon is low (very young/old crescents), the earthshine is invisible - it's tough to get earthshine when less than 24hrs from New Moon. Extinction in the lowest 2-3 degrees can hide it too. Too high a Moon makes the foreground small. The key parameter is height above the horizon for a particular solar depression: You want the Moon in the deep blue part of the sky with yellow-orange below. Simple elongation from the Sun can be misleading as an indicator.

Other considerations:

• shifting focus due to changing temperatures. I deliberately put a focus point on a building so I can do a quick autofocus between exposures without stopping the sequence or moving the camera.

• distance and haze: more distance means bigger buildings/foreground relative to the Moon, but it also means more haze, which adds a lot of light scatter for night shots; less distance of course means a smaller Moon relative to buildings or fewer buildings, but it typically means the Moon disappears at a higher altitude.

• time-lapse locks you in; no freedom in changing position or zoom (without a second camera/lens)

• Is there motion in the foreground? The eye is forgiving to car movements, but in winter plumes tend to jump around even at 6 second intervals and can be quite distracting. Consider long exposure "frame-dragging" to blur (e.g. 0.8s exposure every second) - this might necessitate a second camera to capture the Moon in shorter bursts and more post-processing. It begs the question of moving into HDR video then compressed later. Would still need to think about whether to blur or skip sub-frames. Oooof.

• A constant foreground and a blank dark sky produce a slightly surreal (uncomfortable) result, almost cartoon-like

• Have two foreground shots, one before, one after, shoot only for the Moon, then afterward composite the Moon onto a foreground that is a blend of the two: 100% of the light on the first foreground sliding to 0 for the last, while the second foreground slides up from 0 to 100%. Of course, there is no movement in the foreground, just changing lighting conditions.