The Basics of Lunar Astrophotography - A Guide to Taking Photos of the Moon

by: OZScopes - The Australian Telescope Experts

Moon Picture, with camera settings
This picture was taken using a Celestron NexStar 5SE Computerized Telescope, with the aid of a Moon filter and Adobe Photoshop. Credits to Celestron Images.

Getting Started on Mesmerizing Moon Photography

Moon astrophotography is probably one of the most fun - and easiest - forms of astrophotography. In fact, many novice astrophotographers begin with pictures of the moon due to its relatively close distance to us, as well as the number of details (i.e. craters, rilles etc.) available to focus on.

That said, a good pictures of the moon - full and bright, hovering over a beautiful landscape - can be incredibly aggravating, especially if you're not sure what you're doing.

If you're trying to get started on taking your own lunar photographs, this guide will try to shed some light on the enigmatic world of moon photography and attempt to jumpstart your efforts

The Phases of the Moon - Timing? It's Everything

It will be important to try and understand the phases of the moon - how else will you know when you can get snaps of a crescent or full moon?

The moon goes through its phases based on Earth's relative orbit to the sun. There's a great article from Moon Connection that does a fantastic job of showing the moon's appearance at different points in its orbit.

Moon Phases
Phases of the Moon - credits to Moon Connection

The moon keeps a very regular schedule as it moves across the sky, and you'll either be able to find that schedule online or chart it on paper yourself. It might be useful to try and get accustomed to the moon's cycle by observing it for a month using the diagram above (props to Moon Connection), to learn about the current phases of the moon.

You should then try and figure out when the moon with rise and set in your location using a tool like Time and Date - which will calculate the moorise, moonset and moonphase for yoru location.

Once you're armed with that data, you'll be able to start planning your moon photo shoot.

Moon Photo Shoot Checklist

1. I know the Moon's schedule in its orbit across the sky.
2. I know what phase the Moon is currently in.
3. I know what time the Moon rises and sets today.

Getting Started - Do it early!

So, when's the best time to take a photo of the moon?

If you've ever tried, you'll likely have been frustrated with the results. Although our eyes do well adapting to the discrepancy in brightness between the moon and the dark background of the sky, our digital cameras are generally far more limited.

For the sake of this section we'll assume that we're trying to take a photo of the Full Moon.

When we try to gaze upward at the moon, it doesn't look terribly bright - but to our cameras, it's like taking a picture of a giant ball of light. When you take a picture of something like the moon, it's almost as if you're trying to take a picture of a halogen lightbulb - all you'll see is a big white splotch!

To avoid this, try to catch the moon when it's rising. The moon is "fullest" (during a full moon) when it is in balance with the sun, and thus the moon will rise approcimately at the same time the sun sets. This makes this moment during dusk ideal for photography, in line with what's known as the Golden Hour Principle. During this time, lighting is softer and more diffused, and will also be warmer in hue - this reduces the intensity of direct light, so more illuminations comes from indirect light, allowing for less harsh images.

Unfortunately, this will result in you encountering several difficulties, especially if you're using your camera in the city. You'll be likely to encounter buildings, trees or other obstructions to your view of the rising moon, delaying your viewing. In situations like these, you'll be best to get your shot of the full moon the day before the moon is full. This way, the sunlight in the foreground will more evenly match the intensity of the sun reflected off the moon.

When you shoot the Moon when it is lower in the sky, or especially near the horizon, you will be shooting through more of the Earth's atmosphere. Just as the Sun is dimmed when it is viewed through thick atmosphere, so is the Moon, so exposures will have to be increased when the Moon is low in the sky. Local atmospheric conditions, such as haze and humidity, can also affect the brightness, and hence the exposure of the moon.

Proper Exposure

Moon Picture, with camera settings
This photo of the full Moon was made with a 400mm lens and a 1.4x telecompressor making the optical system have a focal length of 560mm.
An f/stop of f/11 and a shutter speed of 1/250th of a second was used at ISO 1600.
Daylight white balance was used with a JPEG file type. The image was made with the lens and camera on a fixed tripod. Credits to Jerry Lodriguss.

Exposing for lunar astrophotography can be more than a little tricky.

Start out by selecting the lowest ISO that your camera is capable of.

Secondly, if your camera has spot metering, use it and aim the post to cover as much of the moon as possible - this will give you the most accurate reading your camera is capable of. Because the moon is usually small in the frame - unless you're using about 1,000mm of focal length or more - the meter will read mostly the dark sky background and overexpose the Moon.

If your camera doesn't have a spot metering setting, expose it as if it was a sunny day. Although the moon may seem particularly bright to you (or perhaps it's pitch black outside), remember that your eyes and brain do much better controlling for exposure than your camera can. If you're not going to be capturing many foreground objects (e.g. trees, branches, buildings etc.), you should be fine with your aperture set to about f/4. Otherwise, you migjht want to use something like a f/11 or f/16 - this will ensure that your foreground objects will also be in focus.

Moon Picture, with camera settings
This picture was taken using a Canon EOS500D at 1/60 Exposure. Credits to Celestron Images.

For a rough guide to the right exposure settings for the different phases of the moon, refer to the table below. Credits to Jerry Lodriguss.

Moon Phase Exposure
Full Moon 1/250th sec at f/11 at ISO 250
Gibbous Moon 1/125th sec at f/11 at ISO 250
Quarter Moon 1/60th sec at f/11 at ISO 250
Wide Crescent 1/30th sec at f/11 at ISO 250
Thin Crescent 1/15th sec at f/11 at ISO 250
Earthshine 2 sec at f/2.8 at ISO 250

You will find that a tripod might come in handy, especially if you're planning to take advantage of the entire scene in the sky - in fact, for most people, a tripod may be absolutely necessary for stable, shake-free images. If you're planning to use your telescope for astrophotography rather than a large lens (with which you should start with at least a 100mm zoom, and keep going for longer if possible - Canon's 100-400mm L and NIkon's 200-400mm are very handy for lunar photography), you will have to consider two attachments, and you can read more about them below.

Digital SLR Astrophotography

If you are planning to use a Digital SLR with your telescope for astrophotography then there are 2 main accessories you should consider, T-Adapters and T-Rings. If you would like to look at the full range of them you can find them here.

So first up is the T-Ring. The T-Ring is an attachment that you screw into your camera's lens groove to be able to connect to your telescopes. Here at OzScopes, we stock T-Rings for most of the major dSLR brands – namely Canon, Nikon, Minolta and Pentax, so chances are we've got the right T-ring to fit your camera.

Next up is the T-Adapter. These are adapters that you fit into your telescope in lieu of an eyepiece (remove the eyepiece and slot in the T-Adapter instead). Your T-Adapter will then attach to the T-Ring which is on your camera. Voila! Your camera is now attached to your telescope! We've got 3 different types of T-Adapters listed on our website catering to different telescopes:

If you've got a telescope with a 1.25 inch eyepiece, you're good to go with the Celestron Universal T-Adapter – 1.25”. This T-Adapter will fit most telescopes, especially if it is a reflector or refractor style telescope.

If, on the other hand, you own the NexStar 4SE, the C90 or C130 Mak, then this T-Adapter is the one for you: the Celestron T-Adapter for NexStar 4, C 90 Mak and C 130 Mak. There's also another T-Adapter for all the other Cassegrain telescopes (the bigger telescopes) – namely, the 5” to 14” models – which is the Celestron T-Adapter (C5, 6, 8, 9-1/4, 11, 14).

Take note – if you own one of the models listed for the Celestron T-Adapter for NexStar 4, C 90 Mak and C 130 Mak, or the Celestron T-Adapter (C5, 6, 8, 9-1/4, 11, 14), you should try to get whichever of the two corresponds to your telescope. Although you can use the Celestron Universtal 1.25” T-adapter, you might experience a vignetting effect around your pictures with telescopes with a 5” aperture and above. With aperture sizes of 8” and 9”, you will definitely experience some vignetting.

Point and Shoot Digital Camera Astrophotography

So if you own a standard point and shoot camera (e.g Canon IXUS) there are still options for you to get some great astrophotography shots. Getting started requires just one tool (a lot simpler huh!) a Universal Digital Camera adapter. In terms of variety of choice you have 2 options, one being the Saxon Universal Digital Camera Adapter and the Celestron Universal Digital Camera Adapter. With the Celestron, you do pay a little bit more, but you get the associated brand-name, after sales service, and a slightly superior build.

These digital camera adapters perform the same function as a T-Ring – however, instead of screwing your camera onto the telescope, the digital camera adapter 'holds' your camera right up to the eyepiece of your telescope. Now, you might be thinking why you'd want to do that because you could do the same thing with your hands, but it is far more stable when you use an adapter than if you held it there on your own. You're probably already aware, but when you're taking pictures, stability is paramount for a clear, well-focussed image.

Read more about our General Guide to Beginner's Astrophotography here.

Now that your aperture is all set, turn the ISO as low as possible to reduce the amount of noise as possible. It's here that a tripod will come in handy - since you want to reduce noise by lowering the ISO (light sensitivity) levels, you will get a longer shutter speed. When your shutter is open for an extended period of time, it will be extremely susceptible to hand movement if the camera's not on a tripod, resulting in blurry, shaky pictures.

With the ISO low to cut noise, the aperture small to get depth of field and your lens zoomed out to at least 100mm, you are safest when using a tripod.

Anything less than shots taken in full daylight will really benefit from the use of a tripod.

Remember that the Moon is moving constantly, both because of it is revolving around the Earth, and because of the Earth's rotation about its own axis. The Moon moves its own diameter, 1/2 degree, in about 2 minutes. As a general rule of thumb, you can shoot through your telescope for about 2 seconds before the Moon's movement becomes objectionable in the final image.

Once you have a photo that you're happy with, you'll probably want to get round to some post-processing. There's many things you can do with several different programs - such as Adobe Photoshop, or Adobe Lightroom - the first of which should be cropping the moon so it fills the frame.

Find below a quick guide to suggested camera settings for your dSLR camera during Astrophotography. You should be able to find equivalents for many point-and-shoot cameras as well. You can read more about each setting explained at AstroPix.

Camera settings
    - Set Program Mode to Manual Exposure.

    - Set Drive to Single Shot.

    - Set ISO to 400, 800 or 1,600 based on ambient temperature.

    - Turn Image Review OFF.

    - Turn Auto-focus Off.

    - Set White Balance to Daylight.

    - Set File Format to raw (or raw + JPEG).

    - Set Optical Resolution to the highest (native) setting.

    - Turn Long-exposure noise reduction Off if you are planning on shooting separate dark frames, Turn On if you are not.

    - Turn off in-camera shaprening if you are shooting JPEGs at a high ISO.

    - Set contrast and color saturation to normal if shooting JPEGs.

    - Set color space to Adobe if extrememly knowledgeable about color spaces, sRGB otherwise.

    - Turn off flash.

    - Set exposure to Bulb.

    - Put Compact Flash Card in camera.

    - Use a remote release to open the shutter, or self-timer if you don't have one.

    - Mirror lockup is not necessary for long-exposure astrophotography with a decent mount. Use for high-resolution planetary work.