How to photograph next week's lunar occultation of Mars

How to photograph next week's lunar occultation of Mars

Capture the Red Planet disappearing behind the Moon with a smartphone or digital camera.

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Published: December 2, 2022 at 9:30 am

 Mars will be occulted by the Moon early in the morning on 8 December, the day the planet is also at opposition.

Mars opposition is a big deal for Mars, presenting the planet at its largest and brightest for the current period of observation – great news for anyone wanting to capture an image of this uncommon event.

In this guide we'll show you how to photograph the Mars occultation for yourself.

For more info, read our complete guide to the lunar occultation of Mars.

See Mars reappear from behind the Moon during the lunar occultation. Credit: (c) 2010 Luis Argerich / Getty Images

Photographing with a smartphone

The planet will be bright enough that many smartphone cameras may well be able to photograph it.

If this is how you plan to record the occultation, head outside on a clear night before 8 December to see whether yours can.

Some are able to detect low light conditions and adjust accordingly.

If yours can’t do this, see whether it offers a choice of manual camera settings either natively or via a downloadable app.

A Google search of your phone’s make, model and ‘astrophotography’ may provide advice on settings.

Point your phone down the eyepiece

It’s unlikely that your phone can capture the planet as it slips behind the edge of the Moon or out from behind it an hour later, but it may be possible to achieve this afocally by pointing your phone down the eyepiece of a correctly focused telescope at the time of the occultation.

An eyepiece holder is highly recommended here and can be obtained relatively inexpensively via astronomical equipment stockists.

If you plan to use just a phone camera, consider mounting it on a tripod with an inexpensive phone holder.

A headphone cable with a volume control sometimes works as a remote shutter release.

Try it out in the days before the occultation by opening the camera, attaching the cable and pressing the ‘+’ volume control to see whether your phone takes a picture.

Aim to take shots when the Moon is near to Mars either before or after the occultation – this should give the best results.

If your camera has zoom capability, use optical zoom rather than digital zoom.

Digital zoom takes the highest optically zoomed image and rescales it, with no advantage other than looking impressive on your phone’s screen.

Photographing with a digital camera

Credit: Gajus / iStock / Getty Images Plus

Photographic cameras fitted with telephoto lenses will get you in closer to the action.

Below 1,000mm focal length, aim to capture the Moon with Mars as a dot nearby.

Make a correct exposure of the Moon first, then adjust so Mars is nicely shown.

Take a series of several images at, say, five-minute intervals leading up to the occultation.

These can be overlaid, setting the upper layer’s blend modes to lighten.

Finally, bring these together with the properly exposed Moon shot to make a stunning rendition of the event.

Mars will present an apparent disc size of 17.1 arcseconds on the night of the occultation.

Although 105 times smaller than the 1,803-arcsecond apparent diameter of the Moon, a close-up on Mars will show it as a disc.

With a telephoto setup you can capture the event in its full glory, as long as you pay attention to the brightness difference between Mars and the Moon.

Follow our step-by-step guide below and see how well you can do capturing this rare and exciting event.

Credit: Pete Lawrence

Photograph the Mars occultation, step-by-step

Step 1

[caption id="attachment_101807" align="aligncenter" width="1024"]Photo of a man standing in front of a smartphone on a tripod, capturing a nighttime landscape Credit: meatbull / Getty Images[/caption]

Basic kit such as a smartphone can be used to photograph the occultation.

Practice on a clear night before 8 December to see whether you can record the orange dot of Mars.

An inexpensive smartphone tripod is recommended for best results.

Point your camera at Mars to see whether it can automatically adjust settings for a night shot.

Step 2

smartphone image info data

If you manage to successfully capture Mars, find the image info data (normally provided while viewing the shot) and note the settings.

Work out how to set your camera’s phone into manual mode to replicate the settings.

A correct exposure for the Moon will record Mars as rather dim so you may need to slightly over-expose it.

In manual mode, ensure focus is set to infinity.

Step 3

phone remote shutter release headphones

Alternatively, mount your phone over the eyepiece of a correctly focused telescope to take your shot.

An inexpensive eyepiece holder will make the alignment required a lot easier.

In-ear headphones with a volume control on the cable can sometimes work as a remote shutter release cable.

Again, the best technique is to experiment on a clear night before the occultation.

Step 4

mars vs moon

If you have a high-frame-rate planetary imaging setup, grab a correctly exposed image of Mars immediately before or after the occultation, either in mono or colour.

A full RGB capture of Mars can be done at this time.

Similarly, grab a correctly exposed shot of the Moon’s surface near disappearance or reappearance too. 

Step 5

photographing moon and mars

You can record Mars and the Moon’s surface in the same frame; don’t worry about over-exposing the Moon.

The Moon’s motion makes it hard to record a sequence for stacking though.

Instead, record the disappearance and reappearance as a video sequence, each frame recording Mars’s position relative to the lunar limb.

Step 6

mars occultation disappear reappear

It takes around 35 seconds for Mars to disappear and to reappear.

If capturing a high-frame-rate sequence, a video editor such as VirtualDub (freeware) can be used to extract frames (at 1-second intervals, say) that can then be brought together to produce a composite representing what the view looked like visually.

Have you managed to photograph the occultation of Mars? Get in touch via contactus@skyatnightmagazine.com or via Facebook, Twitter and Instagram.

This guide originally appeared in the December 2022 issue of BBC Sky at Night Magazine.

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