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View KATU's video stream of the planet Saturn and its rings

An image from video of Saturn taken through a telescope on KATU's roof Sunday, July 16, 2017. (Photo: Steve Benham/KATU.com)

This summer offers the best views of Saturn's rings in nearly 15 years.

They tilt 27 degrees to our line of sight and offer a stunning view through any telescope.

In honor of such a view, I live streamed Saturn through a telescope Sunday, July 17, 2017. I set up a telescope on KATU's roof. It was a bit breezy, which often made the image jittery, but when things settle down, seeing was pretty good. Below, is a clip from that stream.

Original story and other details:

Through a small telescope, the planet’s disk appears yellow-brown and is encircled by its magnificent rings. A small number of the planet's moons can also be seen.

But not everyone has a telescope, so we’re attempting to bring you a live look at the sixth planet from the sun using a telescope set up on KATU’s roof and a special video camera loaned to us by OMSI. Right now, Saturn is almost due south in the sky and is hanging out in the constellation Ophiuchus, the Serpent Bearer.

If you go outside, you can see Saturn with your unaided eyes. It’ll appear as a bright “star.” But don’t confuse it with the red-looking star Antares not far away to the west. You can tell you’re looking at Antares because it’ll be twinkling. Saturn won’t be twinkling.

And just in case you’re wondering, Saturn is about 841 million miles from us. If you could drive straight there at a constant speed of 65 mph, without stopping at rest areas or the minimart for coffee, it would take you about 1,477 years.

Saturn is made up mostly of hydrogen and helium with ammonia clouds, while its rings are a collection of ice and rocks bound together by gravitational forces.

Want to see the planet with your own eyes through a telescope? Weather permitting, OMSI offers free star parties once a month from March to September at Rooster Rock State Park and L.L. Stub Stewart State Park. There are many opportunities to view Saturn and many other celestial wonders during these events. Check out OMSI’s event page for times.

What you’re seeing:

The quality of the video image will depend largely on seeing conditions. While clear skies are important, seeing conditions are a more important factor. Even if the sky appears to be perfectly clear without a visible cloud, the turbulence in the atmosphere can sink any hope of getting a clear image of a planet.

When there is a lot of turbulence in the atmosphere, instead of a perfectly steady image, you’ll see one that boils or shimmers, especially around the edges of the planet. The more the boiling and shimmering there is, the worse the turbulence. At its worst the image will “fuzz out.”

This effect is more pronounced when the object is closer to the horizon, when the light has to travel through more of the earth’s atmosphere to reach the telescope and the camera. Thus, the higher the object is in the sky, the better, because the light is traveling through less atmosphere.

ClearDarkSky.com is forecasting poor to average seeing conditions for Portland tonight, so we'll see how things turn out.

Why is the Image so Small?

Besides Saturn being so far away, there are a couple reasons. A larger image will mean the effects of turbulence will be more obvious. Secondly, since the earth is constantly rotating, the stars, the planets, the moon and the sun appear to move across the sky. So, I’ll need to “track” Saturn as it does so; otherwise, it’ll move out of frame. Keeping a smaller image framed will be a lot easier than keeping a large one happily in view. Perhaps in the future, I can try higher magnifications.

What Equipment Am I Using?

Someone out there is bound to be wondering, so here’s my setup.

I’m using an 8-inch f/6 reflecting telescope. That means the diameter of the telescope’s primary mirror is eight inches. The primary mirror is secured near the bottom of the telescope tube. (The bigger the mirror, the fainter the objects and details the telescope can “see.”) An 8-inch telescope is a moderately sized amateur telescope.

The way a reflecting telescope (also known as a Newtonian, since Isaac Newton invented it) works is as follows: The light from an object, say Saturn, travels down the telescope tube and bounces off the primary mirror, which is slightly concave, and is sent back up to the tube where it encounters a smaller, secondary mirror suspended in the middle of the tube near the top of the scope. The secondary mirror sends the light out the side of the telescope. It is here an eyepiece is inserted into a focusing tube. The eyepiece provides the magnification.

The mount I’m using is called an equatorial mount. Simply put, this means that a telescope on a properly polar-aligned equatorial mount can be moved precisely along two axes: A north-south axis, and an east-west axis.

Is this tracking manual or automatic? It’ll be a little bit of both. The telescope is about 25 years old and doesn’t have the best tracking motor. So I’ll be helping it along often.

What about the camera? The camera is an Orion StarShoot Deep Space Video Camera. It’s an older camera and only does composite video. OMSI has loaned it to us this summer so we can live stream celestial objects, such as Saturn. Through experimentation, the shutter speed for Saturn will likely be set at either 1/250 or 1/500 of a second for proper exposure. With the help of a KATU engineer, I’ve hooked the camera up to the station’s in-house video system which will allow me to route the video signal to our web video encoder for streaming on the website and Facebook.

Also note: the video camera goes in place of the telescope’s eyepiece.

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