Spinoffs from supernova hunting


Even I have to admit it: supernova hunting is boring. I take pictures of 10,000 galaxies per year, on average, and I'll find only 5 supernovae in that time period. Another way to look at it is that I shoot galaxies on 250+ nights per year. Thus, you could either say that I look at 9,995 galaxies per year and don't find a supernova in any of them, or you could say that I search for supernovae on 245 nights per year and don't make a discovery. That's a lot of time spent, and a lot of galaxies imaged with no discoveries made!

Now you take ol' M 95 here, for instance. I've shot this galaxy on 73 nights over the past 10 years, and I've never discovered a supernova in it. In 2012, I heard about a supernova in M 95, and I took some pictures of it. But that wasn't a "discovery" for me. And I haven't seen a supernova in it since then. So, you could also say that I've been looking at this galaxy for 13 years without finding a supernova in it.

Yeah, I think that qualifies as boring!

To mix things up a bit, I started to keep track of asteroids that I encounter in my searches. One of the benefits of supernova hunting is developing a large database of galaxy images, taken over a span of many years. So, if tonight my telescope-control software shows an asteroid in the field of view of a particular galaxy, I can blink the current image with an older image and see the asteroid (as shown above). 

The other night, while shooting M 95, I saw that asteroid (1633) Chimay was in the field. Having such a low number for an asteroid, I knew it should look pretty bright in my images. So, without taking the time to figure out which "star" was the asteroid, I merely made a note of it and then searched for it in my images the following day.

While blinking the images, the asteroid was certainly obvious. But another star caught my eye. It was brightest in the reference image and dimmer in the image with the asteroid. Although sky conditions can vary, causing stars in an image to appear brighter than they do on a different night, this one star was brighter, and the rest stayed the same. Hmmm. Must be a variable star! 

I used Aladin to identify the star of interest and it proved to be an RR Lyrae type of variable star, varying between 14th and 16th magnitude. I assume that the "ZTF" in the name means that it was discovered by the Zwicky Transient Facility, my competitors in supernova hunting! In any case, I just happened to choose a reference image with the star near maximum brightness and I blinked it with the current image when the star was near minimum brightness. What luck!

I've always appreciated and respected the work of variable star observers. And I think it would be fun to follow a variable star and create my own light curve. But it's terribly difficult, in my opinion. Variable star observing requires a type of patience and dedication that I don't seem to possess! I've been a backyard stargazer for 45 years and, for whatever reason, I've never been able to keep up with a variable star. If it's a short-period variable like Algol, I can't dedicate myself to get out there and get images of it through a complete cycle. And if it's a long-period variable like Mira, I tend to forget all about it after a few months. Variable star observing just doesn't fit my personality! But it's fun when I can "discover" a variable star like the one pictured above, as a spinoff to supernova hunting.  

Supernova hunting has opened up a whole new dimension of imaging for me! Since I have to compare tonight's images with images from long ago to find supernovae, the dimension of time has become a huge part of my image processing. While other amateur astrophotographers may find faint new objects in their images by going deep with 50-hour exposures and using an assortment of fancy color filters (H-alpha, RGB, sodium, etc.), I am using relatively short (20 seconds), unfiltered exposures to find objects that change over time. 

Perhaps I should have named this post "The Time Filter." Blinking images uses the filter of time to reveal objects that would likely go unnoticed by any other means.

 

My picture of the supernova in M 95 in 2012

Comments

Post a Comment

Popular posts from this blog

Kids these days!

Image
  When I was 9 years old, this was the house I lived in. The little boy that you can see there above the Chevy pickup is my 10-year-old brother. And that's my dad up there, smiling in the window. He was reshaping the existing window to please my mother who said, "I have to have a window over the kitchen sink. I'll be happy if I can look out a window while I'm washing the dishes."  Inside view of the completed kitchen window Of course, at that time, there was no kitchen sink in our house! It had no indoor plumbing! Our water came from a 25-foot well just a few feet from the back door. We used an old-fashioned hand pump, probably from the 1930s, to pump water into a bucket and then we'd carry the water into the kitchen for drinking, cooking, and bathing. A rain barrel under one corner of the barn roof collected enough water to use for priming the well, as needed.  The hand pump, our only source of water when we moved to the farm. Our bathroom was also old-fashio...
Read more

My first photograph of Pluto

Image
The year was 1987. I had been a backyard astronomer since 1980. During those 7 years, I felt like I had made good progress in the hobby. I was on my 4th telescope, a Meade 8-inch Schmidt-Cassegrain. I had tracked down nearly half of the Messier objects. I had seen the moons of Jupiter and the rings of Saturn. I was practiced at the art of astrophotography with color negative film, having shot a lunar eclipse in 1982, Halley's Comet in 1985 and 1986, and numerous deep-sky objects at the prime focus of my 8-inch f/5 Newtonian reflector. So, when I received the May issue of Astronomy magazine in 1987, and saw the article on page 100, titled "Where to Find Pluto[:] Spring and Summer 1987," I felt ready to accept the challenge to take a photo of the most distant planet in the solar system.  To be honest, before reading that article, I had never given any serious thought to hunting down Pluto. I didn't know much about it. Nobody did. I knew that it wouldn't look like m...
Read more

The life of a supernova hunter

Image
  Supernova in galaxy NGC 2146 I found a supernova in NGC 2146 last night. No, I was not "the discoverer" of the supernova. That would be the Japanese astronomer Koichi Itagaki. He discovered it 5 days earlier. But I didn't know it. I came across it on my own during my nightly search for supernovae in the distant galaxies. Supernova hunting has been my hobby since 2016, and supernova 2024abfl is the 21st supernova I've come across. You can look up supernovae on Wikipedia, so I won't waste your time by describing them here. What I would like to talk about, however, is the sport of supernova hunting.  Supernova hunting falls under the umbrella of backyard astronomy. If you were to purchase a telescope to get a closer look at the stars and planets, there are a number of astronomical activities you might eventually become interested in. Like most people, you'll probably be disappointed in the dull-gray eyepiece views of nebulae and galaxies, after seeing brilliant...
Read more