Long Distance Voyagers

The 1970s saw the amazing beginning of our explorations of the outer Solar System. Pioneer 10 launched in 1972. It became the first space probe to fly through the asteroid belt and past the giant planet Jupiter. About a year later Pioneer 11 was launched on a journey to both Jupiter and Saturn. The exploits of these two probes are forgotten by many but they paved the way for their successors, Voyager 1 and 2.

Voyager 1 flew past Jupiter and Saturn, while Voyager 2 visited these two gas giant planets and the ice giant planets of Uranus and Neptune.

Their flybys past these giant planets put the Pioneer and Voyager probes on trajectories that propelled them out of our Solar System and into interstellar space. The Pioneer probes functioned until the early 2000s. The Voyagers are still in operation and have been returning data on the region of space just beyond the influence of our Sun.

The four probes are completely invisible to our telescopes, but it is possible to look at where they are in the sky. I’ve spent some time this year looking at three of the four probes. Voyager 2 left the plane of the Solar System after its flyby with Neptune in 1989. As a result its position in the sky is too far south to be seen from my location on Earth.  

In late February I pointed my Unistellar eVscope at the location of the Pioneer 10 probe. It’s in the direction of the constellation of Taurus, the Bull, along one of the Bull’s horns At the time its distance from us was 127.7 times Earth’s distance from the Sun (127.7 astronomical units). That’s almost 12 billion miles. At that distance, if we could still receive radio messages from it, it would take almost 18 hours for them to cross the gulfs of space to reach Earth. That's 18 light hours. While that is quite far, keep in mind that the nearest star to the Solar System is more four light years away.

You can’t see Pioneer 10 in this image, but it is there, somewhere near the middle, alone and drifting outward as it will do forever.

Knowing exactly where to look is simplified by use of a planetarium program such as SkySafari Pro. Here’s how I used it to track down my next target, Voyager 1. It is in the huge constellation of Ophiuchus, near to its border with Hercules.  SkySafari Pro gives me its coordinates and a visual image of its location against the starry sky. Next I point my trusty eVscope to the coordinate and take an image. Remember, the probe itself is completely invisible, but for me just knowing that Voyager 1 is out there somewhere in that field of stars is enough for me to stop and wonder.

In the image above I've blinked my photograph with the SkySafari Pro finder chart which marks the location of  Voyager 1. 

How far is Voyager 1 from Earth? 153 astronomical units. That’s over 14 billion miles. Its feeble radio signals that reach back to Earth take more than 21 hours to get here. 

My final target isn’t as far away as Voyager 1, but it is in a more visually interesting position of the sky. Pioneer 11 is only 105 astronomical units from Earth. It is in the direction of the small constellation of Scutum, the Shield. More importantly it is just under 8 arc minutes (a minute of arc is 1/60 of a degree) from the globular star cluster known as NGC 6712. This means that if you ever observe the star cluster with a wide-field telescope there’s a good chance that you’ll also be seeing the location in the sky of Pioneer 11, and just maybe a photon or two of reflected light from the spacecraft. 

Pioneer 11 is somewhere near the middle of this image. The light of the stars in the cluster take more than 26,000 years to reach Earth while any reflected light off of Pioneer 11 takes 14.5 hours to reach Earth. 

Here's the finder chart from SkySafari pro marking its location in the sky.

 There’s one other object made by humans that is speeding out of the Solar System. That’s the New Horizons spacecraft which flew past dwarf planet Pluto in 2015 and then to the small Kuiper Belt Object known as Arrokoth three and a half years later. I haven’t targeted that region of the sky yet. Maybe I’ll do so sometime soon on a clear summer night.

The Nebulae of the Messier Catalog: Ranked

Note: All of the images in this post, with the exception of the two star maps and the one image from the Hubble Space Telescope, were taken by me with my 4.5" Unistellar eVscope.

In the 1700s a French comet hunter named Charles Messier compiled a list of things in the night sky that aren’t comets. As someone who was actively looking for comets, this represented his list of things that could be ignored because they aren’t what comet hunters want to find. His list of not-comets is a catalog of more than 100 objects that represent some of the finest objects in the night sky. The list is mostly made up of star clusters and galaxies, but there are 12 nebulae. 

Nebulae (that’s the plural for nebula) are clouds of gas. They come in different types and the 12 that are found on in the Messier nicely represent them. Here are images of the 12 Messier nebulae and I decided to rank them, because, why not?  (Note: there are some other nebulae that are sort of in the catalog. For instance there's a little nebula that can be seen when looking at open star cluster M46, but I decided not to include those here.)

The 12 Nebulae of the Messier Catalog in numerical order.

 

M78

 

Number 12: M78. M78 is dark and moody. It’s the kind of nebula that is okay with the fact that it doesn’t have a widely used proper name. It’s nothing more than a reflection nebula, something that is produced as light from its two central stars passes through the dust. Darker clouds of dust surround the brighter region cloaking M78 in mystery (except when viewed in the infrared. There's an entire cluster of stars there).

 

 

M43 is the little luminous blob in the middle.

 

 

Number 11: M43, De Mairan’s Nebula. Who was De Mairan? I confess that I had to look him up. Jean-Jacques Dortous de Mairan discovered this nebula (according to Wikipedia “some time before 1731"), but frankly this nebula really shouldn’t be classified as its own thing. I mean it’s right there with the fabulous M42. There’s some dark interstellar dust that makes M43 seem like a separate thing, but they really are connected making M43 somewhat of a poser on the edge of greatness.
 

 

Number 10: M76, the Little Dumbbell Nebula. That's "dumbbell", as in barbell and as in M27, the actual (not little) Dumbbell Nebula, which we’ll get to later. M76 is a planetary nebula which, as I tell my students, has nothing to do with planets at all. Many of these nebulae are small and round and blueish green in color, much like the planet Uranus. Sir William Herschel, who discovered Uranus, thought that these looked a bit like his planet, so he gave them the name planetary nebulae. Because of this astronomy students have hated him for years. 

In a planetary nebula gas is being ejected out from a dying star. The hot core of the dying star heats the surrounding gas and makes it glow like the gas of a neon sign. M76 is small, but it has distinct colors that are easily revealed with the eVscope making it a nice target. 

Owl Nebula with a satellite photobombing the image.

 

 

 Number 9: M97, the Owl Nebula. The Owl is another planetary nebula and gets its distinctive name from two large dark areas like “eyes” that make it somewhat reminiscent of an owl’s face. It is faint and takes some time to really see it well, but it is a cool thing nonetheless.

M1, the Crab Nebula

 

Number 8: M1, the Crab Nebula. The Crab gets extra points for being the only supernova remnant in the bunch, but let’s be honest, it looks nothing like a crab. It was produced when a star exploded as seen from Earth on July 4, 1054 A.D. The eVscope reveals it easily, though it takes some time to see much color here. No matter how you slice it, it is cool to observe a hot cloud of expanding star guts.

M20, the Trifid Nebula

 

Number 7: M20, the Trifid Nebula. Stars. Gas. Dust. The Trifid has it all. The red comes from a glowing cloud of hydrogen gas which is cut across by dark dust lanes, that help to give it its distinctive name (Trifid means tri-lobed). The faint blue color comes from starlight shining through dust (like sunlight shining through a dirty car windshield), similar to what we saw in M78. It’s an all-round good nebula.

 Number 6: M27, the Dumbbell Nebula. Like M76, the name means barbell, though according to Wikipedia it is sometimes known as the Apple Core Nebula, which is a name I like much better than Dumbbell. Alas, I’ve never actually heard anyone use that name and I fear that if I start calling it the Apple Core Nebula no one will know what I am talking about. It’s another planetary nebula. As you can see it is a big (about 1 light year across) bubble of gas seen against a dense field of stars.

Let’s face it, bubbles are cool and this is likely one of the biggest you’ll ever see. Of the planetary nebulae in the Messier catalog, this one is the closest which also makes it the one that has the largest apparent size. 

Number 5: M17, the Omega Nebula (also called the Swan and other names too). This giant cloud of hydrogen gas is a site of active star formation which means that the nebula is converting itself into a cluster of stars. It has already formed many stars, but they are largely hidden by the nebula itself. Some of the younger, hotter stars that have formed shine on the gas cloud and make it glow.

M17, the Omega Nebula

Location of the Ring Nebula. Image from SkySafari Pro.

Number 4: M57, the Ring Nebula. The Ring is awesome. It is another planetary nebula, so we are seeing gas that has been ejected by a dying star. The Ring always impresses people when they see it through a telescope. I remember once years ago (when I was working at Lake Afton Public Observatory in Wichita, Kansas) I was using a 16-inch telescope to show the Ring Nebula to a young lad who then described it as looking like a “dimly-lit Cheerio.” His description was perfect and much better than the “smoke ring” description that most people use. Of course, the eVscope quickly reveals its colors (something you won’t see at the eyepiece of traditional telescopes). This color perhaps makes M57 more like a Froot Loop than a Cheerio. 

Bonus points are given to the ring for being so easy to find in the sky, it is easily found even without using a go-to telescope. It is nestled between two stars in the parallelogram of Lyra, the Harp.

M57, the Ring Nebula

Number 3: M16, the Eagle Nebula. No star death here. Like M17, the Eagle Nebula is a glowing cloud of gas that is actively giving birth to stars. In fact there’s a cluster of baby stars (NGC 6611) that have already emerged from the nebula. This nebula was made famous by the “Pillars of Creation” image from the Hubble Space Telescope. The pillars are easily visible in my image. Here’s a comparison of my image next to the one from Hubble. The Hubble image is presented in a different and not very realistic color palette, but it beats my image in every possible way (as it should). Still it is nice to capture something that famous with my little telescope. The Pillars themselves are 4-5 light years long and are sites of active star formation in the nebula. 

M16, the Eagle Nebula

Number 2: M8, the Lagoon Nebula. While I didn't rank this as number 1, I confess that the Lagoon is perhaps my favorite. It is another star-forming nebula like we saw in M16 & M17, but it has so much more. There's good color, a prominent dark dust lane that cuts across it, a great star cluster (NGC 6530), dark clouds of dust that lurk at the edges of the main nebula, but also dark blobs of dust (called Bok Globules) that are revealed in silhouette. I like everything about this nebula. The region is too big to completely fit into the field of view of the eVscope. Below is a mosaic that I took of the area:

Messier 8, the Lagoon Nebula

And the best Messier nebula is....

Location of Orion Nebula (image from SkySafari Pro)

 

Number 1: M42, the Great Orion Nebula. When you have the word "great" in your name there shouldn't be any doubt as to your status. The Orion Nebula is bright and super easy to find. It sits in a prominent spot in Orion, which is arguably the brightest and most famous constellation of them all. Pretty much everyone can find the three stars that make up the Belt of Orion. The Orion Nebula is the middle "star" of the Sword which hangs down from the Belt. It is easily seen without any optical aid if you are away from light polluted skies. It looks fine in binoculars and good in every telescope. 

 

Like the Lagoon, this nebula is too big to see all at once, so I took a mosaic of the region:

M42, the Great Orion Nebula

Yes, M43 is hanging on there on the left, but it's really part of M42. The Great Orion Nebula, which like the Lagoon and the others we've seen, is a vast cloud of mostly hydrogen gas that is actively forming stars. The central white area is overexposed here, but it is home to a group of young stars called the Trapezium which are making the gas fluoresce. There's dark dust, blue reflected starlight and red glowing hydrogen. 

It really is a stunning sight to see.

I am working my way through photographing the entire Messier Catalog, with only a few objects left to get. If I feel super energetic about it I might just rank all 110 of them.  

Denizens of the Kuiper Belt

Pluto, not a planet, but still super interesting

 The Kuiper Belt is an icy swarm of objects that lie beyond the planet Neptune. As you likely know the first member of the Kuiper Belt to be discovered was Pluto back in 1930. At the time it was given planetary status and was for decades was thought of as being a lone, unique object on the edge of the Solar System. That changed with the discovery of 1992 QB1 (now known as 15760 Albion). Since that discovery several thousand objects have been discovered out beyond Neptune. The discovery of Eris, an object that initially was thought to be larger than Pluto brought the question of Pluto's planetary status into focus. Should it remain classified as a planet or be regrouped with its many thousand neighbors? Pluto really is much more similar to the other worlds that orbit the Sun in the Kuiper Belt than it is to any of the other eight planets of our Solar System.

With that in mind in 2006 the International Astronomical Union decided to take on the issue and in the process invented a new category - Dwarf Planet. They named (promoted?) five worlds to dwarf planet status. One of them comes from the asteroid belt (Ceres) and the other four are members of the Kuiper Belt. They are Pluto, Eris, Haumea and Makemake. (By the way, there are other worlds that should also be given this status, but the IAU shows no interest in adding worlds to the "official" list at this time.)

Eris, Haumea and Makemake were all discovered using the 48-inch Schmidt telescope at Palomar Observatory, a telescope considerably bigger than my little Unistellar eVscope, yet all three of these worlds can be found photographically with small telescopes. 

Earlier this year I realized that I should be able to photograph not only Pluto (the brightest of the bunch), but Haumea and Makemake too. The trick in capturing these worlds is to have a good set of coordinates, a good finder chart (I use SkySafari Pro) and to look at the worlds on two different dates so as to capture their motion in the sky. This makes them easy to distinguish from a star.

By the way, these worlds are far from the Sun, which means that they don't move very fast, so much of their motion that we see is really due to Earth's orbital motion. This changes our perspective on these objects relative to their position as seen against the background stars. A thing that astronomers call parallax.

My first target was Makemake. At the time it was 51.7 times farther from Earth than Earth is from the Sun. That's almost 4.8 billion miles. It's just 888 miles in diameter and has a surface of reddened frozen methane.

Can Makemake be photographed with the 4.5" eVscope? Yes, it can. I observed it on April 1st (no fooling!) and 2nd of this year. I made two exposures of 15 minutes, aligned the images with Photoshop and produced this animated gif showing its motion against the starry background. Can you spot it?

Okay, that's tricky, but it is there. I'll make it easier with this version that is both cropped and annotated:

Bingo!

That gave me the confidence I needed to move on to Haumea. Haumea is an amazing world that is somewhat football shaped, coated with water ice and makes one complete rotation in just 3.9 hours. None of those features would be easily detectable with my little telescope, but they are interesting.

I looked for Haumea on April 9 & 10 of this year when it was 49 times farther from Earth than Earth is from the Sun. That's around 4.5 billion miles away.

Though fainter, it was certainly detectable.

This  image has been cropped from the full frame, but there it is.

Pluto was my next target, but I needed to wait until summer to catch it because I need my sleep. 

Pluto is both larger and closer than Haumea and Makemake, making it much brighter. It's the brightest Kuiper Belt Object, which is certainly why it was the first one discovered.

When I imaged Haumea and Makemake I used 15-minute exposures to catch them. Pluto was obvious with just a two minute exposure. Here it is. Can you spot it?

This image (and the ones of Haumea and Makemake too) is essentially a recreation of the technique that was used by Clyde Taumbaugh at Lowell Observatory when he found Pluto back in 1930, but things were much, much tougher for Mr. Taumbaugh. He had to be outside in the cold Flagstaff air while I was inside my comfortable home. His images were recorded on glass photographic plates that had to be developed and then he had to compare images to look for a moving object on the hundreds of images he took over nearly a year. I had the tremendous advantage of knowing exactly where to look. 

In case you couldn't find Pluto in the image above, here's one that has been zoomed and annotated:

As far as I am able to determine Pluto, Haumea and Makemake are the only members of the Kuiper Belt that can be imaged with an eVscope. The only other dwarf planet that can be seen with an eVscope is asteroid Ceres, which is a very easy target. I have imaged Ceres, but will perhaps post that in a later post on asteroids.

And We're Back...

After a break of just over a year and a half it is time for me to start blogging again.

Since mid November of 2020 I have been spending a lot more time under the night sky imaging astronomical objects from my backyard (also while I sit comfortably inside too).  The main reason for my change in behavior has been because I decided to purchase an eVscope from Unistellar Optics.

The telescope, pictured at left with the constellation Orion in the background, is a 4.5" telescope with an imaging system fully integrated into it. It is controlled by an app from a smartphone or tablet and it is amazingly easy to use. It is every easy to set up and its low weight makes it extremely portable (though I pretty much never go anywhere except my backyard). 

My yard is small and there are many tall trees nearby which can block large portions of the sky. This means that some parts of my yard have a good view of the east, others the south and there's one particular spot that has a limited view of the west. For any traditional backyard observing this would be a huge challenge, but not for the eVscope. It is not uncommon for me to finish looking/imaging at one part of the sky and then pick up my telescope to move it to another part of the yard. It is then a simple matter for the telescope to figure out where I've moved it to (an operation that takes less than a minute) and then we're off to the next target. 

With this telescope I have been able to successfully image the Moon, stars, galaxies, asteroids (including making citizen science observations of an asteroid occultation), comets, Kuiper Belt Objects, supernovae and more. 

I post a lot of my pics on social media, but I'll be using this space to put some of them here where I've got the room to talk about whatever moves me. 

So I figure I can't get away from this post without leaving at least one astrophoto here, so have a look at the galaxy known as Centaurus A:

Centaurus A is a peculiar galaxy which lies over 10 million light years away. It is possibly a giant elliptical galaxy, but it has a major dust lane cutting across it, which is not a thing that giant elliptical galaxies usually have. Like most big galaxies Centaurus A has a supermassive black hole at its center (this one has a mass 55 million times greater than our Sun!), but this one is quite active emitting radio waves, X-rays and jets of gas moving at relativistic speeds (none of which are visible here).

I had only seen this galaxy though a telescope just once before and I was a little worried that I might not be able to pick this up with my new telescope as it is a southern object that never gets very high in the sky for northern observers. I looked the best possible time, but even so it less than 15 degrees above the horizon and just over a big hill (some might call it a small mountain) that almost blocked my view. I am happy that my eVscope delivered a nice view of this mysterious galaxy though its electronic eyepiece and I was able to capture the image above. 

I've taken a great many images of astronomical objects in the eight months that I've owned this telescope, so expect to see more of them here soon.