International Space Station Shines A Light On Mid-Winter Nights

The International Space Station cuts a path between Orion and the Hyades cluster last night over Duluth, Minn. At left the station fades and then disappears as it enters Earth’s shadow. For the next couple weeks, the ISS will be making one or two passes a night over many locations. Details: 20mm lens, ISO 400 with about a one-minute time exposure. Bob King

We’ve now gained 40 minutes of evening daylight and 10 minutes in the morning. Can you tell? I noticed the shift yesterday when I was driving home in sunset-pink air around 5 o’clock. Back in mid-December, the sun bid farewell at 4:21 p.m. with twilight well underway by 5.  I’m no fan of summer’s long days but a little extra daylight doesn’t hurt. Sure takes the edge off the current cold snap. Cold may be uncomfortable, but polar air masses often bring clear skies. And if you dress warmly 15 minutes of starry skies a night may be all you need to avoid that stuck-inside feeling.

This is how our planet looks from 250 miles up viewing from the ISS cupola. Now that’s a window seat! NASA

I’ve got an enticement for you. The International Space Station has just returned to the evening sky for a fine series of passes now through mid-February. I caught my first one yesterday evening just after 6:30 p.m. local time and am looking forward to more. The ISS is the brightest of the satellites because it’s enormous. Spanning 356 feet (109 meters) it’s not only as long as a football field but wide enough to include the amphitheater seating.

On occasion, other much smaller satellites will “flare” and momentarily outshine the space station but when it comes to consistent brightness, the ISS is tops. At best it easily outshines Jupiter and almost Venus.

Like many satellites the ISS was launched into an orbit that tracks from west to east across the sky, opposite the motion of the sun, moon and stars. NASA and other space agencies do this to get a free boost from Earth’s west-to-east rotation so they can save on fuel. Earth’s rotation rate varies by latitude. At the poles it’s 0 mph; 736 mph at 45° N and 1,040 mph at the equator. NASA would be nuts to build a spacecraft launch facility in Minneapolis when they can put it in southern Florida and gain an extra 180 mph of free orbital speed. To figure out how fast the planet spins at your home, click here and enter your latitude. Don’t know your latitude? Click here.

Three spaceships are parked at the space station (as of today, Jan. 25) including the Northrop Grumman Cygnus resupply ship and Russia’s Progress 71 resupply ship and Soyuz MS-11 crew ship. There are currently three astronauts on board the station. NASA

The ISS starts low in the west but soon climbs into good view. As it rises higher for an observer it also gets closer to us and brighter. When it passes directly overhead the ship is closest because there’s only about 250 miles (400 km) between you and the station with zero horizontal distance. If you see it off to the north or south, it’s 250 miles and hundreds of miles distant in the horizontal or line-of-sight distance. If you’ve done much ISS-watching, you’ll notice that it’s brightest when somewhat east of the overhead point. That’s because the station is now opposite the sun and lit up fully like a full moon.

You can find the space station and get a map showing its path by using Heavens Above. Click the link, select your city and then tap the ISS link for a list of passes for the coming nights. Click on a date to see a map and timeline. Or go to NASA’s super-easy Spot the Station site for times. You can sign up there to get e-mail or text alerts whenever there’s a favorable pass over your city. Or you use an app like ISS Spotter for iPhone or ISS Detector for Android and customize your viewing. No matter which route you go, you can’t go wrong. I’ve included a table of pass times for the Duluth region is at the end of the blog.

If you’d like to try and photograph the ISS, you’ll need a tripod and a camera that can do a time exposure of at least 15 seconds. Set your lens to manual (M) and shutter to “M” as well. Get outside five minutes before the ISS arrives, focus on a bright star, then compose your image and wait for the station to pass through the frame.

For exposures longer than 30 seconds (the built-in limit even for many high-end cameras) you can either carefully hold down the shutter button with your finger or buy a remote release that you can click on for as long as you need. When using the release be sure you turn your shutter speed knob to “B,” the setting that lets you expose for as long as you want. I typically set my camera to ISO 800 and f/2.8 (wide-open) for 30 second-or-less exposures and ISO 400 and f/3.5 for those lasting between 1-2 minutes. Experiment in advance of the space station to see what gives you the best exposure.

Clear (if cold) skies!

The View From Duluth, Minn. (updated 1/29)

  • Tues. Jan. 29: A low pass in the northern sky from 7:05-08 p.m. Watch for a dramatic disappearance in Earth’s shadow at 7:08.
  • Weds. Jan. 30: Nice, bright pass across the northern sky from 6:14-18 p.m.
  • Thurs. Jan. 31: Pass across the northern sky from 6:59-7:02 p.m. The station disappears in Earth’s shadow directly below the North Star.
  • Fri. Feb. 1: Bright pass across the northern sky from 6:08-12 p.m.
  • Sat. Feb. 2: Partial pass in the north from 6:53-56 p.m. with disappearance in Earth’s shadow

7 Responses

  1. Dana

    I will try to see the ISS this weekend (thank you for the article), hopefully it won’t be too cloudy.
    In your last section “The View From Duluth, Minn, I think the dates and days of week are shifted by one day. For instance, Sat. Jan. 25 would be Fri. Jan. 25 instead.

    1. astrobob

      Hi Dana,
      THANK YOU for catching that. I was looking ahead a little too hard! Much appreciated and now updated 🙂

  2. Edward M Boll

    I love watching the Space Station. I pointed it out one evening to our church members.I guess that I need to brave the cold weather. But lately, I have been inside. I have said good bye to Comet 64, and was going to to 38 tonight. But at 10 below, I found it more comfortable looking at the February positions of Iwamoto inside my house from the internet. I well remember Hyakutake, found about this time of year 23 years ago. I mentioned this to a professor at SDSU, and in moments he had printed off an orbit. It was my first look at the internet. My good byes to 38 and 64 May be a little premature. Not yet expecting to find them any more, I may point optical aid in their direction looking at stars near their positions.

  3. Edward M Boll

    I am letting Wirtanen go lately. I was going to view it tonight in the 7 below chill, but settled instead for a film in town. Now, dimmer than mag 7, the comet is beginning to be challenge for my 20 power binoculars.

    1. astrobob

      Edward,
      I should have tried for it last night but was working on other astro stuff. Maybe the next clear night.

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