Observing High Proper Motion Stars

Everything in the universe is in constant motion, even the stars themselves. Yet the stars are so far away that the constellations of the night sky seem to be essentially unchanging. But, everything is moving. 

The various motions of the stars and our own Sun through space can make the nearby stars appear to change their positions relative to more distant background stars. Alas, none of these are the stars that shine brightly in our sky. 

61 Cygni is a binary star that is 11.4 light years distant and can faintly be seen under dark skies. The two stars of the 61 Cygni system are a little smaller and cooler than the Sun. They take over 600 years to orbit about each other. 

I used my Unistellar eVscope to take an image of this system in September 2021 and again earlier this week. As you can see in the image below, this system of two stars is indeed moving relative to the more distant background stars:

This is motion known as 'proper motion' and, I confess, wasn't something that I thought I would be able to see, because I hadn't actually given it much thought and I am happy to know that for the right stars this is pretty easy to observe. The main thing needed (other than the telescope & camera) is time.

61 Cygni isn't alone in having a high proper motion. Other stars have it too. One of them is known as Lalande 21185. It is a red dwarf star located just 8.3 light years from Earth, but it is too faint to be seen without a telescope. Here's an image from June 2021 blinked with one from earlier this week:

Finally, here's the star with the highest proper motion: Barnard's Star:

Like Lalande 21185, Barnard's Star is a cool red dwarf star that is too faint to be see without a telescope. It is located just six light years from Earth.

There are other stars that are near to us that have high proper motions and I'll be spending some of my evenings looking to see if I can catch them as they move through the skies.

A Supernova and Two Comets

We've had a wet and rainy winter and early spring. That gave way to an intense "May Gray" and a solid "June Gloom" during the first half of this month, so there hasn't been much time for astronomy this year. 

Thankfully, I had a short and fortuitous break in the clouds early in the evening of May 20th. Just one day earlier a new supernova had been discovered in M101, the Pinwheel Galaxy. I had imaged the Pinwheel last year, so I had an appropriate image to blink with the new one to show the appearance of the supernova.

That's the supernova blinking on and off on the right side of the galaxy. It is a Type II supernova, which marks the collapse and explosion of a massive star. M101 is located 21 million light years from our Milky Way Galaxy, meaning that the star exploded 21 million years ago and its light has only now just reached us. 

The rest of May remained cloudy and I wasn't able to see it again until June 15th. It's still visible. This type of supernova stays bright for many weeks, so it will be quite some time before it fades completely away.

Two faint comets have captured my attention recently. One of this is known as C/2023 E1 (ATLAS).

E1 ATLAS is a short period comet, with an orbit of 85 years. It is currently in the inner Solar System and crossing the orbit of Venus, but if you look at its orbit from the side (below) you can see that it is highly inclined (tipped) relative to the orbits of the planets.

It is a relatively faint comet, but has had an outburst recently which has made it an interesting target to observe. Below I have animated two images of the comet to show its motion against the background of the stars:

I captured the all  of images here with my Unistellar eVscope, which nicely reveals the comet's blue-green color. 

I recently targeted an even fainter comet, that *may*, in the fall of 2024, become one that will be very bright. It is known as Comet C/2023 A3 (Tsuchinshan–ATLAS). 

Here's where it currently is:

Yes, it is out past the orbit of Jupiter. Usually comets aren't observed until they get much closer to the Sun. Since A3 is at a much greater distance from the Sun than where comets can normally be observed that means that is it brighter than normal, which might mean that is will become a spectacular, dare I say, Great Comet --but not until it gets closer to both the Sun and Earth and that will not happen until the fall of 2024. 

However, it is faintly observable with a telescope right now. It's small and faint so I cropped and annotated the image so that it could be seen here:

That little dot is chunk of ice that is coming in from the Oort cloud and in about 16 months it will make a pass through the inner Solar System. As it gets closer to the Sun heating will vaporize parts of the comet which likely will give the comet a temporary atmosphere (known as a coma) and a tail or two. If it follows expectations the comet will become brighter than Venus and be easily seen without any optical aide, but comets are famously unpredictable, so only time will tell how it will really look. In the meantime, I'll be looking at it as often as I can.