{"id":47708,"date":"2023-07-14T07:31:02","date_gmt":"2023-07-14T07:31:02","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=120398"},"modified":"2023-07-14T08:32:38","modified_gmt":"2023-07-14T08:32:38","slug":"photograph-saturns-rings-before-they-disappear-from-view","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/photograph-saturns-rings-before-they-disappear-from-view\/","title":{"rendered":"Photograph Saturn\u2019s rings before they disappear from view"},"content":{"rendered":"

Catch the planet this year, as over the next few years Saturn\u2019s rings are going to tilt away from our view. <\/p>

By Jane Clark\n \t\t<\/p>

Published: Friday, 14 July 2023 at 12:00 am<\/p>

\n\n

T<\/span>here are few things quite as captivating as seeing the rings of Saturn<\/a> for the first time.<\/p>\n

On 27 August 2023 Saturn will reach opposition<\/a>, when it lies directly opposite the Sun relative to Earth and will be at its brightest and highest, clearly visible at magnitude +0.4 and reaching around 25\u02da in <\/span>altitude from the UK.<\/p>\n

You can find Saturn in Aquarius in 2023 and into 2024.<\/p>\n

\""Saturn\u2019s\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Saturn\u2019s rings appear brighter near to opposition than at other times, as this compare and contrast shows. Credit: Pete Lawrence<\/span><\/figcaption><\/div>\n

At the start of August, Saturn will be at its best after midnight.<\/p>\n

It rises earlier as the month goes on, becoming more of an evening object and by opposition is up all night.<\/p>\n

It will be relatively low, so we\u2019ll be looking at Saturn through more of our own atmosphere.<\/p>\n

Normally, this isn\u2019t ideal for imaging, but you\u2019ll want to catch the planet this year, as over the next few years Saturn\u2019s rings are going to disappear.<\/p>\n

Don\u2019t worry! They\u2019ll be back. It\u2019s just that the apparent tilt of Saturn\u2019s rings varies over its 29-year orbit.<\/p>\n

Saturn\u2019s tilt and rings<\/strong><\/h2>\n
\""Saturn\u2019s\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Saturn\u2019s tilt means its rings are becoming more edge on. By late 2025 they\u2019ll be virtually impossible to see (for a few months). Credit: NASA<\/span><\/figcaption><\/div>\n

In 2023<\/strong>\u00a0Saturn\u2019s rings are tilted down at a 9\u02da angle at opposition<\/p>\n

In 2024<\/strong> they\u2019ll be just 3.7\u02da<\/p>\n

By 2025<\/strong>\u00a0they\u2019ll disappear into an almost imperceptible line as Earth views them edge on.<\/p>\n

After that they\u2019ll become increasingly visible as the southern pole of the planet tips towards us, reaching their maximum inclination of 27\u02da in 2032.<\/p>\n

In a way, the rings being less tilted is an opportunity as you can watch the rapidly orbiting moons more easily.<\/p>\n

\""Saturn\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Saturn at opposition, 18 July 2022. Credit: Padraig Connor<\/span><\/figcaption><\/div>\n

Personally, I love to image Saturn, capturing the planet\u2019s bands on camera and tracking how the moons move around it.<\/p>\n

Why not make 2023 the year you get started in planetary photography and record the rings before they go?<\/p>\n

Doing so is now easier than ever, and it\u2019s even possible to capture the planets under skies with a lot of light pollution<\/a>.<\/p>\n

I encourage you to have a go \u2013 the results can be extremely satisfying.<\/p>\n

Planetary imaging takes practice. You might not immediately get prize-winning astrophotos, but with this guide you should be able to get an image you can be proud of.<\/p>\n

Recording a video of Saturn\u2019s rings<\/strong><\/h2>\n
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A Bahtinov mask will help keep your targets pin-sharp.<\/span><\/figcaption><\/div>\n

There are several types of cameras you can use for astrophotography, such as DSLRs, smartphones, modified webcams and dedicated CMOS planetary cameras \u2013 all of which I\u2019ll come to in a moment.<\/span><\/p>\n

They all follow the same basic principle of recording a video of the planet, thereby capturing thousands of images in quick succession.<\/span><\/p>\n

The weakest link in any optical setup is Earth\u2019s atmosphere and an effect known as seeing<\/a>, which causes light travelling through it to shimmer.<\/span><\/p>\n

We can\u2019t predict moments of low shimmer, but videoing means we can be sure to catch them and then only use the best frames from a video during the processing stage.<\/span><\/p>\n

Before you begin photographing the planets<\/a>, it\u2019s important to make sure your optical setup is as sharp as it can be.<\/p>\n

Make sure refractors are well-collimated if needed and then focus using a nearby star. You may want to consider using tools like a Bahtinov mask<\/a> to make sure your optics are pin-sharp.<\/p>\n

\u00a0<\/p>\n

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The real-time live view in SharpCap Pro, showing the camera control panel where you can set exposure times and more.<\/span><\/figcaption><\/div>\n

There are two main planetary image-capture programs nowadays: SharpCap and FireCapture. FireCapture is freeware.<\/p>\n

SharpCap has a pro version, currently \u00a312 per year, with some handy extensions such as a method of polar alignment for equatorial mounts, but there is also a stripped-down, free version.<\/p>\n

Planetary cameras are generally supported via their own drivers.<\/p>\n

\""FireCapture\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
FireCapture in action. It allows you to adjust the gain, gamma and exposure settings for your camera.<\/span><\/figcaption><\/div>\n

For webcams, you may need to set up a driver using an app called the ASCOM platform, obtainable for free from ascom-standards.org<\/span>.<\/p>\n

ASCOM drivers can do all sorts of things, from controlling filter wheels to managing electric telescope focusers, and ASCOM\u2019s capability is increasing all the time.<\/p>\n

With all cameras, it\u2019s best to very slightly overexpose the image and pull back during processing, using the \u2018gamma\u2019 control.<\/p>\n

Be sure to capture the planet in a movie format \u2013 the most commonly used are AVI and SER.<\/p>\n

Smartphones and DSLRs<\/strong><\/h2>\n
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Credit: Charlotte Daniels<\/span><\/figcaption><\/div>\n

It\u2019s possible to take planetary photographs with a DSLR or even a smartphone, with the help of adapters.<\/p>\n

DSLR adapters fit directly into your telescope\u2019s eyepiece holder, and you can find out more about this in our guide on how to connect a DSLR to a telescope<\/a>.<\/p>\n

Smartphone telescope adapters<\/a> will also require an eyepiece as they hold your phone\u2019s camera over it, allowing you to capture a view similar to what you\u2019d see with your eyes.<\/p>\n

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Be sure to align the smartphone holder precisely or the brightness of the image will fall off catastrophically.<\/p>\n

The camera needs to be centred over and laid flat against the eyepiece so that the edges of your view through the eyepiece appear sharp.<\/p>\n

These kinds of images are great if you\u2019re just looking for a quick snap to remember the night or want to test the waters of planetary photography, but they\u2019ll be of limited quality.<\/p>\n

Although DSLRs can be excellent for serious deep-sky astrophotography<\/a>, I have never seen detailed planetary images taken with either DSLRs or mobile phones.<\/p>\n

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By overexposing Saturn you\u2019ll start to pick up its major moons. Credit: Jane Clark<\/span><\/figcaption><\/div>\n

You should be able to see the outline of the planet, the rings and perhaps Saturn\u2019s largest moon Titan, but that\u2019s about it.<\/p>\n

If you overexpose, you can pick up more moons, so long as you don\u2019t mind the planet being whited out \u2013 a technique you can use with any of the cameras described in this article.<\/p>\n

Using a webcam<\/strong><\/h2>\n
\""With\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
With some DIY adjustment, HD webcams like the Logitech C270 (top) and Microsoft LifeCam (bottom) are a cheap option for imaging planets.<\/span><\/figcaption><\/div>\n

One budget-friendly option to capture good planetary images is to use an adapted webcam, which can cost as little as \u00a335, though it will need to be connected to a computer to operate and collect data.<\/p>\n

Many cameras are suitable, for example the Logitech C270<\/a> or Microsoft LifeCam<\/a>.<\/p>\n

Preferably, you\u2019ll want something that shoots in AVI format, though other acceptable formats are SER and MPEG files.<\/p>\n

If yours only does MOV files, you will need to buy a program to convert them. It\u2019s also wise to check whether your image-capture software supports your particular model.<\/p>\n

\""Saturn\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Saturn photographed with a Sky-Watcher 150\/750, NEQ3-2 mount, Barlow x3, Logitech C270 webcam. Credit: Houssem Ksontini<\/span><\/figcaption><\/div>\n

To adapt the camera, carefully prise off the front of the housing with a knife or a screwdriver and unscrew the lens.<\/p>\n

In its place, attach a 1.25-inch telescope-eyepiece-to-webcam adaptor ring, which needs to be purchased separately but will make keeping the camera in position in your telescope\u2019s draw tube much easier.<\/p>\n

Cover over with tape any LEDs which might affect your imaging, then close up the front of the camera.<\/p>\n

You can usually use at least part of the original housing to do this, then seal any gaps using waterproof glue or tape to prevent dew falling into the camera.<\/p>\n

CMOS cameras<\/strong><\/h2>\n
\""Jane\u2019s\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Jane\u2019s observatory setup with ZWO ASI662MC (right), Celestron scope and driven mount all linked to her PC.<\/span><\/figcaption><\/div>\n

Low-cost, high-speed CMOS cameras are well-suited to astrophotography and have come down tremendously in price over the last few decades.<\/p>\n

You can now get an excellent one for under \u00a3300.<\/p>\n

I have an ASI662MC from ZWO\u2019s almost bewilderingly large range of planetary cameras.<\/p>\n

Other brands you may want to look at are the Atik GP colour camera and the Opticstar range, which have lower frame rates, but the latter are around half the price of ZWO models.<\/p>\n

You can either use a colour camera or a monochrome camera with filters.<\/p>\n

I strongly favour colour cameras because the images are easier to process.<\/p>\n

Plus, the fickle British climate does not always allow time to take four separate luminance, red, green and blue<\/a> images, and the filter wheels required to make the rapid filter changes are expensive.<\/p>\n

But is it worth buying a separate planetary camera if you already have a cooled colour camera for deep-sky work?<\/span><\/p>\n

The answer is simple: you can obtain much higher frame rates with purpose-built planetary cameras.<\/span><\/p>\n

\""CMOS\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
CMOS camera configuration for photographing the planets.<\/span><\/figcaption><\/div>\n

My ZWO ASI662MC can shoot hundreds of frames per second.<\/span><\/p>\n

My cooled deep-sky camera, a ZWO ASI2600MC, can only manage a few frames per second. <\/span>It\u2019s designed for long exposures, not short ones.<\/span><\/p>\n

Fast cameras can capture planets even if there\u2019s a lot of cloud around.<\/span><\/p>\n

At 100 frames per seconds, you can shoot 6,000 frames in a minute, which is great for \u2018snatching\u2019 images in between the clouds.<\/span><\/p>\n

Specialist planetary cameras do need a laptop or PC to control them and to store their image data.<\/p>\n

I used to use a laptop, but as I now have my own observatory, I use a desktop PC with lots of USB ports.<\/p>\n

ZWO now offers the ASiair \u2013 essentially a Raspberry Pi in a fancy cover \u2013 which will elegantly serve this purpose if you want a mobile rig.<\/p>\n

It is controlled from your smartphone and costs about \u00a3330.<\/p>\n

Whatever you use, make sure you have lots of digital storage space to keep your 5,000\u201310,000-frame movies.<\/p>\n

Processing your images<\/strong><\/h2>\n
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The stacking process sifts through all your frames, selects the best (you choose what percentage), then stacks them into one image.<\/span><\/figcaption><\/div>\n

Once you have your first movie, you will quickly notice how seeing makes the sharpness of the image come and go.<\/p>\n

Fortunately, you should have plenty of frames, ideally a few thousand. Software can select the best of these, then combine them together using a technique called \u2018stacking<\/a>\u2019.<\/p>\n

Stacking combines your best frames to create a single image with a total exposure time of all the frames you end up using.<\/p>\n

I may, for example, stack 10,000 frames and, because of poor seeing, only keep 1,000.<\/p>\n

If each exposure is 1\/100 of a second, I effectively have a 10-second exposure.<\/p>\n

Those 10 seconds weren\u2019t continuous, but the best frames gathered during the periods of good seeing; the remaining 90 seconds is thrown away.<\/p>\n

The best software for this is AutoStakkert!<\/a> It\u2019s unbelievably easy to use and a huge improvement on earlier stacking programs.<\/p>\n