Astro Pop: It’s Space Station season again! – Duluth News Tribune

I don’t mind getting up before dawn to watch the sky, but I’m more of an evening person. A friend of mine greets me today around 4 am with peace and a cup of coffee. Seems like a really great way to start. Maybe I’ll get there someday. Right now, I fall asleep around midnight and roll out of bed at eight.

Tianhe unit

I photographed the Tianhe Corridor – the first module of the Chinese space station Tiangong (Heavenly Palace) – last May. Since then, two more units have been launched and docked at Tianhe, completing the station.

Contributed / Bob King

If your day-night cycle is anything like ours, we’ll see a lot of space stations passing by together in the next few weeks. And not just the International Space Station. The completed Chinese station Tiangong (Heavenly Palace) will also join the scene. Both of these science and observation platforms orbit at roughly the same altitude of 250 miles (400 km).

The International Space Station orbits Earth in a very steep orbit, so it’s visible across more of the planet. For the same reason, it can appear high in the sky even to observers living in the northern United States or southern Australia. Tiangong’s orbit is less steep, so it does not reach as high an altitude. Here in Duluth, we only see it in the lower third of the southern sky, but if you live in Jackson, Mississippi, it can pass almost above us.

Tiangong Space Station

A view of the Tiangong station shows the Tianhe core module in the center, a cargo-carrying spacecraft with solar arrays (in the background), the Wentian spacecraft to the left, the Mingtian to the right, and the two Shenzhou spacecraft sharing its multi-docking hub (in the foreground).

Contributed by Shujianyang, CC BY-SA 4.0

Tiangong is also much dimmer because it is much smaller, measuring 180 by 128 feet (55 by 39 meters) or about half the size of the International Space Station. Being smaller in size, it reflects less sunlight. The International Space Station is so huge that its solar panels and other modules can be clearly seen with a telescope 50 times magnified or more once it’s repaired.

For observers in the northern states, the Chinese satellite also appears dimmer because the lower lanes mean that there is more horizontal distance between the observer and the station. The farther away an object is, the dimmer it appears. During a high pass at Jackson Tiangong, he shines like Jupiter. Duluth is roughly equal to Saturn.

Tiangong pass

Tiangong is making a bright pass (magnitude -0.5) over the Duluth, Minnesota area around the same time as the International Space Station on Saturday evening, January 21st.

Contributed by/Courtesy of Chris Pitt, Heaven Above

Since the viewing “windows” for both space stations overlap, I thought it would be interesting to see if they crossed the sky simultaneously. A quick inspection revealed a nice pair of trails for the Duluth region on January 21st. Tiangong will slide across the southern sky from 6:28-31 p.m., while the International Space Station will cross the northern sky from 6:29-32 p.m. in that minute—overlapping will make it possible to see both briefly at the same time by tilting the head back and forth.

Passing the International Space Station

As Tiangong slides across the southern sky on January 21, the International Space Station will pass high in the northern sky and will shine 3 degrees brighter.

Contributed by/Courtesy of Chris Pitt, Heaven Above

You can see if there are overlapping permits for your site by going to Select your city by clicking on the blue button Change the monitoring location and other settings Link. Then go back to the home page and click on the blue button Tiangong Link to open a lanes table that includes time, orientation, brightness, and altitude. Ten degrees (10 degrees) of elevation equals one fist held at arm’s length facing the sky. You can also click the blue button iss Link to a similar table.

Whenever a file Denial The number in the Brightness column (size) the brighter the scroll. The larger the positive number, the dimmer. The amount of “0” is in the gamut from brighter to dimmer. For example, the star Vega has magnitude 0.

Click on any transit time and a map will appear showing the station’s path across the sky. The times displayed are the 24 hour local times for your location, so 18:30 = 6:30 PM local time and 2:15 = 2:15 AM

Next, compare the transit times of Tiangong with those of the International Space Station and check for overlapping or close times when both are visible. It’s that easy.

You can also use for a list of clearances, times, and directions to search for both the International Space Station and Tiangong. Although the site does not provide maps, it is very easy to use. Just enter the name of your city (or the nearest larger city) and hit the enter button. The link above will take you to Tiangong. For the ISS list, click on the white one ISS Observation Link while you are there.

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