Go Long!

Nebulae, star clusters and galaxies are always popular targets in astronomy, but I sometimes like to go long and take a deeper look into the universe. The most distant objects that are consistently visible are quasars. For those who don't know, quasars are infant galaxies that have supermassive black holes in their cores. Black holes, as you might expect, are black, but when they have things like stars and gas clouds falling into them everything around the black hole gets super hot and shines with intense brightness allowing them to be seen from billions of light years away. 

When quasars were first found they were quite mysterious. They looked very much like stars in our own galaxy that were emitting radio waves. Nobody understood what they really were for quite sometime, but the first piece of the mystery to be solved was that they are immensely far away and therefore shining with a brightness that at the time could not be explained. The first quasar to have its distance identified was 3C 273 [Note: Quasars have terrible names!].

Quasar 3C 273

Determining the distance to a quasar is a matter of taking its spectrum to determine its redshift. From there getting the distance of the quasar is pretty straight forward if you understand exactly how the universe itself is expanding. There is still some disagreement as to the exact rate at which the universe is expanding, so the distances that I'll use here are not precise. 3C 273 lies some 2 billion light years from our home galaxy the Milky Way which, because that's how long its light took to get here, means that we see this core of a baby galaxy the way it looked 2 billion years ago.

It's important to put that figure into perspective. The light captured here with my 4.5-inch eVScope left that quasar 2 billion years ago. That was right around the same time that primitive, single-celled life was starting to seriously add oxygen into Earth's atmosphere [this was actually quite terrible for most things that were alive at the time, but that's another story].

The quasar known as PG 1427+480 [See, I told you they had terrible names, though most of them are a nod to their coordinates in the sky.] is marked in the image below:

PG 1427+480 is even farther away, with a distance 2.8 billion light years.  

Hopefully you haven't gotten tired of seeing dots yet. This next one is HS 0624+6907:

HS 0624+6907 is around 4.2 billion light years away. Light from this quasar left it when Earth was very young, around 500 million years before life began here.

The last one in this post is faint, so I've cropped the image from the full frame:

That little dot is a quasar known as S5 0014+81. The image shows light that left the quasar 11.96 billion years ago. Think about that. The light recorded here left the quasar long before Earth itself was formed.  Seeing this can really give you a sense of perspective. 

To find these quasars I rely heavily on the SkySafari Pro app, especially to identify the star fields. There's also a couple of sites on the Web that are helpful. The Frankfurt Quasar Monitoring site is a great resource and there's a text list of over 450 quasars here. There are various Cosmology Calculators online where you can input an object's redshift (z) and get a distance. You can find one here and here.

The Omega Glory

No, this isn't a post about the terrible Star Trek episode with the same name (I haven't blogged about Star Trek for quite some time now), but rather about the amazing globular star cluster known as Omega Centauri.

Last summer I blogged about the Globular Star Clusters of the Messier Catalog. In the post I mentioned that Omega Centauri is located too far south in the sky for Charles Messier to have seen it. The cluster barely makes it into the sky from my home, climbing just 9 degrees above the horizon. (I live at 33 degrees North, for anyone living further north, the cluster is even lower in the sky or not visible at all). Unfortunately a rather large hill completely blocks its view for me. 

Thankfully, I attended a star party in late April that had an unobstructed view of the southern sky and I was able to see this fine star cluster for the first time in years. It was also the first time I was able to catch it using my Unistellar eVscope2 and the view was impressive.

2-minute exposure of Omega Centauri

The cluster is amazing in every way. From dark skies it is visible without the use of optical aid from binoculars or a telescope. The cluster is 4 million times more massive than our Sun, making it the most massive of our Milky Way galaxy's globular star clusters. At its core the stars are so closely packed together that they are estimated to be just one tenth of a light year apart. Keep in mind that the closest star to our own Solar System is over 4 light years away. Imagine what the night sky would look like from a planet orbiting one of the stars within this cluster.

Omega Centauri may very well be the remnant of a smaller satellite galaxy that has been caught and disrupted by the Milky Way.

To put things into perspective compare the view above with that of another globular star cluster, Messier 13 the "great globular cluster in Hercules": 

This image of M13 was also taken with my eVscope, but when the cluster was high in the sky and with an exposure that was 10 times longer (20 minutes, instead of 2)! Don't get me wrong, M13 is a nice cluster, but it's not really "great" when compared to Omega Centauri. 

Why? Not only is Omega Centauri much more massive than M13 (M13 is only 500,000 times the mass of the Sun), but it is also closer to us. M13 is located around 22,000 light years from Earth, while Omega Centauri is 17,000. This closer distance and much greater number of stars make combine to make Omega Centauri truly glorious.

Comets!

Comets are wonderful to observe. I've seen many of them over the years. The first time I ever photographed a comet was on film (Yes, I'm old). I captured comet Halley back in 1986 and comets Hyakutake and Hale-Bopp a decade later.

Probably the next comet I photographed was C/2011 L4 PanSTARRS came around in 2013. Then there was C/2020 F3 NEOWISE which was pretty good. I wasn't blogging in 2020, but I did get some decent shots of it, including this:

Self Portrait with Comet

 

Most comets aren't bright enough to see visually or capture with a DSLR camera, but there usually are several that are within easy reach of a small telescope. 

The very first comet observation I made with a Unistellar eVscope was the night of my first light: November 14, 2020 when I caught Comet C/2020 M3 ATLAS.

My settings for the telescope weren't as good as they could have been, but I was happy to catch something that I wouldn't have caught otherwise. The comet's motion in the sky made it look like a blurred streak, but you can see its tail.

The following spring a different Comet ATLAS, C/2020 R4, came pretty close to Earth. I photographed it April 28th when it was just half an astronomical unit (~47 million miles) from Earth.

In this sequence, which covers just 20 minutes of time you can see that the comet has a faint tail.

2021 also had a much more spectacular comet: Comet C/2021 A1 Leonard which was visible in our morning skies in late November and early December. It was a wonderful comet to photograph. 

Here's an animated gif of Comet Leonard that I took with my eVscope2 on the morning of December 3, 2021:

23 minutes of Comet Leonard's motion against the background stars.

 

On the morning of December 6, 2021 the comet was just 0.4 astronomical units (37 million miles) from Earth:

I again took a number of images, but this time I tried stacking them so that they were all aligned on the comet itself to hopefully bring out more detail on the comet's tail and blue-green coma (atmosphere). Here's the result:

The stars in these sorts of images always look a little strange, but I hope you'll agree that comet's tail and coma are more prominent here.

Afterwards Comet Leonard got even better, but that was a sight for observers in the Southern Hemisphere.

So when is our next bright comet coming? No one really knows. According to Visible Comets in the Future our next comet that might reach naked eye brightness is Comet C/2022 E3 ZTF which is expected to be bright enough to see in January and February of next year, though the brightnesses comets are notoriously difficult to predict. 

The brightest comet that is currently visible is C/2017 K2 PanSTARRS. Here's an image of it that I took earlier this month:

Comet PanSTARRS should be a little brighter in July when it is closer to Earth and I will be sure to take a look.

Things That Go Bang in the Night

White dwarfs are hot glowing remnants of stars that were at least somewhat like the Sun. Over billions of years of time isolated white dwarfs gradually cool down (possibly crystalizing into Earth-sized diamonds!) and fade away. But white dwarfs that are located in binary star systems can have a much more spectacular time than just gradually dimming from view. 

Artist's illustration of a white dwarf (right) pulling gas from its companion star. Credit: NASA/CXC/M.Weiss

 

In some of these binary systems hydrogen gas is pulled off of the white dwarf's companion star which piles up on the surface of the white dwarf. Eventually there's enough gas there that it detonates producing a nuclear explosion on the surface of the white dwarf. This is what astronomers call a nova. 

The nova explosion does not destroy either star and can eventually repeat. There are 10 of these recurring novae that have been observed to repeat in our Milky Way galaxy. 

One of these recurring novae is known as U Scorpii (U Sco for short). Normally U Sco is too faint to observe with my Unistellar eVscope, but it is an easy target when a nova outburst occurs. On June 6th I got word that U Sco had an eruption underway so I decided to take a look. 

U Scorpii (bright star at center)

One characteristic of this nova is that it fades in brightness very rapidly. To record its fade I have been looking at it periodically since June 6th. Sure enough, it will soon be back to its normal too-faint-for-me-to-see status. The image below shows U Sco dropping in brightness by a factor of 100 in just 10 days. 

The nova is still dropping in brightness and will soon fade from my view entirely. 

A second type of explosion involving white dwarfs is known as a Type Ia supernova. This is a much bigger deal. Again we are talking about white dwarfs in binary star systems, only instead of an explosion on the surface of the star, the entire thing blows apart, most likely from the merger of two white dwarfs (although, maybe not - astronomers are working on that). 

These explosions are big enough for my little telescope to be able to see them from distances of tens of  millions of light years (whereas U Sco is just ~60,000 light years away). 

Last year I was able to observe one of these explosions, supernova 2021hiz, in an obscure galaxy known as IC 3322A. I followed up my observation a year later to produce this comparison showing the galaxy with and without the supernova:

The galaxy is just a faint smudge of a line (it's a spiral galaxy seen from the side) and the supernova is the bright dot on the upper edge that blinks on and off. Notice that the light of the supernova is actually brighter than the rest of the entire galaxy. 

Think about that. One supernova explosion can outshine all the light produced by hundreds of millions of stars. That's amazing.

Another bright Type Ia supernova (sn 2022hrs) took place this spring in a galaxy known as NGC 4647. NGC 4647 is conveniently in the sky next to one of the galaxies in the Messier Catalog, M60. Last year I photographed all of the objects in the Messier Catalog, which means that I had a before image to go with the new image of the supernova. 

Here's the before and during comparison:

This supernova exploded some 63 million years ago and light from it arrived on Earth in mid April 2022. I am happy to have had the opportunity to catch it. 

By the way, the last supernova observed in our Milky Way galaxy was also a Type Ia supernova. It was recorded by Johannes Kepler back in the year 1604. 

Observing Spacecraft

Even though it has been a while since I've updated this blog I've still been doing a lot of backyard astronomy. I've been looking at all the usual stuff (comets, galaxies, asteroids, etc.), but I've also seen a lot of spacecraft. Most of them have been annoying to look at, like this trail from a geostationary satellite crossing into my image of part of the famous Orion Nebula:

Satellites are an ever increasing problem for astronomy as tens of thousands of them are being launched into low-Earth orbit. This is an annoyance for amateur astronomers, but can present serious problems for astronomical observatories both on Earth and in Earth orbit. 

Occasionally it is desirable and even useful to have a look at a satellite or spacecraft. For instance last  November the European Space Agency's (ESA) Solar Orbiter made a close flyby of Earth.

The flyby, which brought the spacecraft less than 300 miles from Earth, was perfectly placed for telescopic observers in North America. Unistellar asked people within their network to observe the event in science mode for ESA and provided an ephemeris which made it easy to know exactly where to point a telescope to observe it. And it was pretty amazing to see.

I observed simultaneously with 2 eVscopes. One was collecting data in science mode, while the other took the image above. The line in the image above is a trailed image of the spacecraft which was visibly moving across the image as the exposure was being taken. The animated gif below shows a speeded up version of the motion of the spacecraft across the field of view (which is rotated from the image above).

The event was a success, I have heard that ESA was happy with the observation campaign and I am glad that I was able to contribute.

About a month later on Christmas day the James Webb Space Telescope finally launched into space and as it moved out to its permanent location in space it was visible to small telescopes here on the ground. 

Here is a sequence of images I took of JWST on January 1st, 2022.

It is visible in the image above as a streak moving from the center towards the upper right. JWST is poised to make significant contributions to astronomy and I was happy to be able to see it. I was one of several observers who contributed science observations of it and we were able to spot changes in brightness as the sunshield unfolded along with other results that will soon be published.

Finally, one other target of note: the International Space Station. The ISS is the largest and brightest of Earth's artificial satellites and it currently has seven people living there. Many amateur astronomers have taken spectacular images of the ISS that show tremendous detail and I was curious to know if I could even spot it at all using a telescope. Thankfully, Unistellar's Ephemeris Generator allows observers to point their telescope at the ISS. The Unistellar telescopes can't track the space station, but instead the telescope it pointed at where it will be at a particular time. 

My first attempt at spotting the station was successful, but the image was pretty terrible:

I was happy that I saw it all, but decided that I could do better and I June 1st I gave it another try. Here's what I saw:

If you blow up one of the frames it looks like this:

Much better. I suspect that I can still improve but the solar arrays, especially on the right, are clearly visible and it is vastly better than my first attempt from May. 

Clear skies!