October 26th: Hot Tub Astronomy

Date: October 26, 2009

Title: Hot Tub Astronomy


Podcaster: Gerry Santoro

Organization: Central Pennsylvania Observers

Description: On warm summer nights I love lying in my back yard and just looking at the sky. Turns out that there are many things an amateur astronomer can do with the naked eye. But late fall through late spring adds the problem of cold weather, which, as we get older, becomes more and more of a problem. The solution – add a hot tub! This podcast will discuss a few of my favorite activities during hot tub observing that anyone can do.

Bio: Gerry Santoro has been an avid amateur astronomer since 1963. He has built a number of home observatories, and now operates Dog-Star Observatory as part of his home Information Sciences lab. He is a founding member of Central Pennsylvania Observers. He is an Assistant Professor of Information Sciences and Technology and Communication Arts and Sciences at Penn State University. Aside from astronomy and information sciences he is an avid martial artist and motorcyclist.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Clockwork Active Media Systems. Clockwork invents, designs, develops and maintains web applications that market, sell, streamline, automate and communicate. Visit clockwork dot net or email inquiries at clockwork dot net to get started on your web project.


Hello, welcome to 365 days of astronomy, Today is October 26. My name is Gerry Santoro. I am a professor of information sciences and technology at Penn State University and a lifelong amateur astronomer. Today’s podcast is on the esoteric theme of “hot-tub astronomy.”

I love being cold
under clear and crisp skies ,
Like Admiral Byrd I brave the chill
and my telescope takes me where i will….
I love the cold

When I was a youngster I would pride myself on taking my telescope out on the coldest nights of the year. I knew these nights were often among the clearest, with cold, dry air allowing my 8-inch telescope to pick up faint galaxies and nebula that would remain hidden on warmer nights. Where I lived the lowest temperatures could reach minus 20 degrees Fahrenheit perhaps not that bad but still pretty chilly.

As I aged into my 40’s and 50’s I discovered that my tolerance for cold was declining. I could no longer use fingerless gloves to take notes. I would start to shiver at temperatures that before would only make me laugh. Trying to stand motionless and really observe a deep-sky object was now a trial. My old trick of doing jumping jacks or running in place to generate body heat succumbed to a bad back and middle-aged legs.

It was during my mid-50’s that I purchased a hot tub for my home. I live along the side of Tussey Mountain in the Appalachians of Central Pennsylvania, and knew the hot tub would make a great addition to my back yard. What I didn’t realize at the time was how the hot tub would re-invigorate my cold weather observing.

My first problem was placement of the tub. I wanted to make sure that it was not in sight of any neighbor’s porch lights or susceptible to light from traffic on a nearby road. I solved this by erecting simple wooden walls across 2 sides of the tub. The other sides faced forest (and the south) and could be left open.

A second challenge was whether to have a roof or not. I knew I would want to use the tub during cold rain or snow, so having no roof at all wasn’t an option. But I also knew that I would want to sit and observe the sky on clear, cold nights. A retractable roof was one option but was too expensive. So I opted for a “half-roof.” When raining or snowing I could sit under the protected half, and on clear nights I could sit under the other half. It worked like a charm.

Then to try it out. I had always loved just sitting under the sky and observing wide fields with my naked eye, or occasionally using binoculars to more closely examine something. Binoculars turned out to be a problem in the tub, as they would fog up within only a few minutes. I learned that a pair of small, sports, binoculars worked best, especially if waterproof.

One favorite hot-tub stargazing activity is satellite watching. By sitting calmly and letting my gaze cover whole quadrants of the sky I could quickly zero in on bright satellites. Web resources such as Heavens Above could then be used to identify those satellites. Sometimes I would purposely plan a tub session to watch a particular satellite, such as ISS or a Iridium flare. I quickly became amazed at how many satellites could be seen.

Another great hot-tub stargazing activity is watching meteor showers. It is hard enough for me to get up in the middle of the night and leave my warm house to lie in a chair and watch the sky for an hour or more. Getting up to move to a warm hot tub for observing is downright pleasant. The only danger here is that of falling asleep in the tub, and I handle that by taking a wind up clock and setting it for 30-minute increments. If you want to try this, start with the Orionids, Leonids, and Geminids, and then as winter progresses the Quadrantids and April Lyrids. After you get better you may try for some of the lesser-known showers. After a while it is fun just to count sporadic meteors. I have been pleasantly surprised on more than one occasion by a bright fireball.

Constellation and star watching is another favorite activity. Although I learned the constellations as a youngster, I could see a person sitting in a hot tub and learning them. Having a waterproof sky map would likely help. Also possibly a laser pointer if doing this in a small group. I would try to push my memory by learning the names of bright stars and a few fun fact about them, such as distance, size, color, variability, etc. I would revel in the fact that looking at a star meant that a photon of light had traveled all that distance and time to enter my mind.

Bright deep-sky objects and comets are also fun to watch from a hot tub. On a crisp October night I may start with M-31, which is easily visible, scan to the double cluster of Perseus, and try to pick up M-33. Following the bright and dark contours of the Milky Way is also fun at this time of year. During late summer and fall evenings our home galaxy would spread from horizon to horizon. From the sparse outer arms of Cassiopea through the rich star clouds of Cygnus and down to the bulge (and great divide) into Saggitarius, the view is breathtaking.

One fall I remember following Comet Holmes as it moved through the evening eastern sky. I would stare at it, or just to the side, for minutes and try to appreciate what I was seeing. Night by Night I would also check on Delta Cephi, a variable star that is easy to track against its closest neighbors.

If you have a northern exposure (or southern exposure in the southern hemisphere) aurora watching from a hot tub can be very rewarding. Various web sites provide aurora information, and some services will even alert you by text message when a large aurora is predicted. Of course all aurora are different, and they are very dynamic, so the best way to observe them is to simply sit back, relax, and watch.

Even when the Moon is out, hot tub astronomy can be fun. The surrounding area takes on a surreal quality under the moonlight. If there is haze you may be able to watch a halo, or moondogs, as they slowly evolve. If there is a low, broken, cloud cover, just watching the clouds move in front of and around the moon can be extremely entertaining. And of course you can learn to identify naked-eye and binocular accessible craters, maria and mountains on the Moon. A lunar eclipse is a particularly rare treat!

In conclusion, I love my hot tub and the way that it has brought me back to the joys of naked eye and binocular astronomy. I would advise having a wool cap on very cold nights to keep your head warm. I’d also caution against the ‘prune effect’, where you get so comfortable that you skin gets all pruney from being in the water.

This concludes todays podcast. I am Gerry Santoro and I wish you all clear skies and happy nights!

And remember…”I like the cold!”

End of podcast:

365 Days of Astronomy
The 365 Days of Astronomy Podcast is produced by the New Media Working Group of the International Year of Astronomy 2009. Audio post-production by Preston Gibson. Bandwidth donated by libsyn.com and wizzard media. Web design by Clockwork Active Media Systems. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. Until tomorrow…goodbye.

About Gerry Santoro

Gerry Santoro has been an avid amateur astronomer since 1963. He has built a number of home observatories, and now operates Dog-Star Observatory as part of his home Information Sciences lab. He is a founding member of Central Pennsylvania Observers. He is an Assistant Professor of Information Sciences and Technology and Communication Arts and Sciences at Penn State University. Aside from astronomy and information sciences, he is an avid martial artist and motorcyclist.

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2 Responses to October 26th: Hot Tub Astronomy

  1. Ulf Jonsson November 7, 2009 at 9:36 am #

    I´ve made up my mind (after the podcast)! There will be an investment at my small house in the country. I will however finish my small observatory before the winter takes over. THEN – I will start building my Hot Tub – the next dimension in northen sky astronomy.

    /Ulf (N65 E21)

  2. Chuck B. October 27, 2009 at 11:27 am #

    I concur, and I now go out several nights per week. Some activities for hot tub astronomy are at http://analyzer.depaul.edu/paperplate/Hot%20Tub%20Astronomy.htm.