5 top tips for taking photos of the naked-eye planets Mercury, Venus, Mars, Jupiter and Saturn
1 Creating simple planet-scapes
The easiest way to photograph planets is to use a mirrorless or DSLR camera on a tripod. This will work with any of the five planets visible to the naked-eye; Mercury, Venus, Mars, Jupiter and Saturn. Choose a wide-angle lens – about 14mm to 24mm – and use a shutter release cable or remote trigger to take long exposure images (of up to about 15-20 seconds maximum). In manual mode dial-in ISO 800, f2.8-f4 and 15 seconds as a good place to start, but do experiment. The planet(s) will essentially appear as a bright star. Pre-dawn and post-sunset is a great time to photograph planets because you can also easily capture the surrounding landscape.
Don’t forget about composition, which can make or break planet-scapes. The branches of trees in the foreground of a shot that includes planets is an easy way to frame a planet and draw the eye to it. Ditto a statue, sculpture or decorative detail on a building. It’s also often possible to capture more than one planet at a time; such ‘planetary parades’ sometimes occur because Earth’s point of view of the solar system shifts as it and the other planets – orbit the Sun.
A great time to capture two planets together in one shot is during a conjunction. This apparent close-passing of planets in the night sky typically occurs over one or two nights in succession when it’s often possible to get them into the same field of view of a small telescope.
The next major planetary conjunction, (at the time of writing), is that of Mercury and Venus in the western sky after sunset on December 28, 2022. The two planets will be just 1.5° apart, which is about the size of two full Moons.
2 Getting technical with telescopes
If you have a big telephoto lens then have a go at a close-up of Jupiter or Saturn, but know that to get a lovely detailed image of a planet (and to see features on its surface) typically requires a telescope, a lot of skill, much expense and many hours of trial-and-error.
This is the realm of astrophotography. Although you can see Mercury, Mars, Jupiter, Saturn and Venus easily in a 2-inch telescope, you’ll need an 8-inch telescope to image them (and likely also a Barlow lens, which further increases the size of the planet in the telescope’s field of view). The trouble is, the Earth rotates quickly so planets drift, which has consequences for exposure time. So unless you have an expensive motorised equatorial mount that tracks with the rotation of Earth’s axis (by aligning to Polaris, the North Star) it’s tricky. Even with that mount the technique requires purchase of a dedicated planetary camera with a high frame rate, which hooks-up to a laptop and has to be controlled using third-party software. You then record a video of the planet, extract the thousands of individual frames from that video and then use software like RegiStax to stack them to lessen the noise.
Good telescopes for planetary imaging include apochromatic (APO) refractors and Schmidt-Cassegrain catadioptric telescopes. They need a large aperture (for maximum light), a long focal length (for more resolution and magnification plus a smaller field of view) and a ‘slow’ focal ratio (the focal length divided by the aperture in mm – the higher the number, the better!).
3 Understanding ‘opposition’
The outer planets – those farther out from the Sun than Earth – orbit very slowly. Saturn, for example, takes 29 years to go once around the Sun. So it makes sense that once each year our own planet passes between it and the Sun. During those few weeks a planet will appear to be at its biggest, brightest and best of the year. Its disk will be fully illuminated (at all other times it’s only partly-lit) and it will rise in the east after sunset and set in the west before sunrise.
Here’s when the outer planets will go into opposition over the next few years:
- Mars: 8 December 2022, 16 January 2025
- Jupiter: 26 September 2022, 3 November 2023, 7 December 2024
- Saturn: 14 August 2022, 27 August 2023 and 7 September 2024
- Uranus: 9 November 2022, 13 November 2023, 17 November 2024
- Neptune: 16 September 2022, 19 September 2023, 21 September 2024
Although a planet can look great on its own, the presence of the Moon – particularly a crescent Moon – can add huge interest and drama to your shot. Check the astronomical events coming up on Telescopius and then use free online planetarium software like Stellarium to see exactly what’s going to happen, where and when.
4 Jupiter, Saturn and Mars
The outer planets appear to move through the night sky gradually. So slowly, in fact, that it’s our own planet’s speedy orbit that is the most important factor in when and where we see them.
The biggest and brightest planet of all, Jupiter is the most reliably easy planet to capture. Definitely try to capture it with a telephoto lens because if nothing else you’ll see its four Galilean moons – Io, Europa, Ganymede and Callisto – strung out in a line either side of Jupiter. Image it with a video camera and you’ll get its cloud belts and its mega-storm nicknamed the ‘Great Red Spot’.
Saturn is smaller and dimmer than Jupiter and Mars. However, its rings make it look truly iconic in a telescope. That’s what any close-up is going for, of course, though because it has a tilted axis like Earth its rings are not always ‘open’. In any 14 year period we spend half the time looking at its southern hemisphere and half the time at its northern hemisphere. For now we’re looking at the latter – and we’ll swap in 2025, so for now we’re looking side-on to the rings.
Since Mars is relatively close to Earth yet moves around the Sun half as fast it only comes into opposition once every couple of years. For Mars its the reddish colour that’s so impressive, with its polar ice caps another highlight for planetary imagers. Mars only really gets big and bright enough to image around its opposition.
When photographing Jupiter, Venus and Mars it’s sometimes possible to capture their light reflecting in water. This can only happen when they’re close to their brightest and it’s usually only noticeable when they’re close to the horizon. It can add an unusual point of interest to landscapes and seascapes. Planets rise in the east and set in the west, the same as stars, Sun and Moon, so a good time to plan such shots is when the planet is in opposition.
5 The motions of Venus
Venus is not like the other planets. Not only is it an inner planet orbiting the Sun more quickly than Earth, but it’s far brighter than the others – thanks largely to its highly reflective cloudy atmosphere. It orbits the Sun every 225 Earth-days, which creates a complicated eight-year pattern during which it can be seen as a “Morning Star” or “Evening Star” for about two-thirds of an Earth-year before swapping. Only appearing ‘full’ when it’s orbiting the other side of the Sun to Earth, it’s half-lit when it’s far from the Sun – from our point of view – and it slims to a thin crescent when it appears to be close to the Sun in our sky. That’s a technically difficult, dangerous yet dramatic photograph.
2023 is set to be a spectacular year for Venus-watchers. It will be big and bright after sunset for much of the first half of the year. On January 22, 2023 it will be seen alongside Saturn in the western sky after sunset and next to Jupiter on March 1, 2023.