How To Photograph The Gas Giants: Jupiter and Saturn
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With just your telescope and DSLR camera, you can capture some amazing views of our bright neighbor planets. You don’t even need a tracking mount!
When I decided to get into astrophotography, Jupiter was at the top of my list of targets. Jupiter was very prominent in the sky all winter. Whenever the clouds cleared off enough to setup the telescope, Jupiter is almost always my first target, particularly with the camera. Now, with Jupiter setting to the west, we have Saturn taking it’s place from the east. Here are some tips to help you capture these brilliant gas giants.
Probably the best method for doing planetary imaging is recording video of the planet through the telescope, then using a program like Registax to align and combine the best frames of the video into a static image. Celestron, Orion, and others sell specific planetary imaging cameras for this such as the Orion StarShoot 5 MP Solar System Color Camera.
Frankly though, that’s a lot of work with specialized equipment and software. You can get really impressive results, but it takes an investment not only in equipment, but most importantly in time. Mind you, I’ll almost certainly find myself doing that process at some point, but for now, I prefer a more general purpose and simple approach.
Fast Exposure Planetary Imaging
Jupiter and Saturn are bright planets – they have a visual magnitude between +1.5 to -3. What this means is you don’t need to take a long exposure to capture their detail. In fact, a long exposure will just wash out all the detail. This means you don’t need a computerized tracking mount. The exposures are short enough that you can point your telescope manually and get an acceptable image.
For Jupiter, you only need an exposure of about 1/20th of a second to capture the cloud bands. If you want to capture the jovian moons, about a 1 second exposure should do the trick. Note that this longer exposure will get you the moons, but wash out the detail of the planet – I’ll talk about some relatively simple editing to deal with this in a minute. For now, just realize that you need two different exposures to capture both the planet and moons.
Turning to Saturn, we have a slightly dimmer but equally magnificent target with the rings. Saturn is currently at opposition, which means the best and brightest viewing opportunities of the year. Even so, it is still a bit dimmer than Jupiter, which means a slightly longer exposure is called for. I found that about 1/5th of a second works well in my setup.
- Lens: Prime Focus to the 6″ SCT (1500mm focal length) with a 2.5x Barlow
- Camera Mode: Manual
- Focusing: Manual using Live View
- White Balance: Daylight
- ISO: 800
- Quality: Highest Quality JPEG (optionally capture in RAW)
- Shutter Mode: Continuous Shooting (A remote shutter release is highly recommended.)
- Exposure Times:
- Jupiter: 1/20th sec
- Jupiter’s Moons: 1 sec
- Saturn: 1/5th sec
Note that the camera settings listed are for my particular setup with a 6″ SCT and Canon T3i camera. If you are fortunate to have a larger aperture telescope, you will be able to take even shorter exposures and capture the detail. If you have a smaller aperture scope, you may need to extend the exposure times a bit.
Focusing can often be a challenge with astrophotography. A camera with Live View makes this easier, particularly with the bright planets. Getting the planet centered and zooming in on the display, you can adjust the focus to where you see the most definition. In the case of Jupiter, look for clear cloud bands. For Saturn, look for well defined rings. If the moon is up, it also makes a great object for adjusting the focus.
Air turbulence is a critical factor with planetary imaging in particular. If you have a camera with Live View that allows you to zoom in, you will be able to see the air turbulence and the distortion it causes on the image of the planet. The only real solution for this is clear, calm air. You will however notice that from moment to moment, the image may appear better or worse. One of the advantages of video imaging discussed earlier is that the software can filter out individual frames of video where the image is particularly distorted due to the air turbulence. When you are doing single exposure planetary imaging, you want to wait for the clear air breaks, and snap off your images during those moments.
DSLR Live Viewing
I’ve been constantly surprised at the little things I’ve learned quite by chance. In this case, it’s just how cool using a DSLR can be not just for imaging, but for observing Jupiter and Saturn without squinting through an eyepiece.This doesn’t work for dim objects, but I find it extremely enjoyable for planetary and lunar observing.
Combining The Best
You may be perfectly happy with a few good shots straight off the camera. If you want to go a little bit further with it, you can take a few of the best images and do a little sharpening and combining in Photoshop or a similar layered image editor. Running a basic sharpening filter on each layer can also help you achieve a cleaner image.
You can stack images just by starting with a base layer, and for each successive layer, reduce the opacity by between 25-50% of the opacity of the layer below it. For example:
- Layer 4: 25% opacity
- Layer 3: 40% opacity
- Layer 2: 60% opacity
- Layer 1: 100% (background layer)
Basic layer stacking is also a way to get a combined image of Jupiter and the Jovian moons by taking the shorter exposure images of Jupiter and the longer exposures with the moons and combining them. You can repeat the above stacking method twice, once for the longer exposures with the moons, and a second time with the shorter exposures of Jupiter showing the cloud bands. Once you have these two stacks, you can overlay the stack with the details of Jupiter into the image with the moons.
Not sure what other gear or adapters you need? Have a look at My Astrophotography Gear.
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