The universe is vast. It’s hard to comprehend just how big it is. For me, this image helps make that visceral. Without any effort, more than a dozen galaxies are visible and, with careful inspection dozens, perhaps close to a hundred are visible in the frame.
These galaxies are part of the Virgo Cluster, a large group of galaxies. You may have recently heard the name of the larger, fuzzy galaxy at the top of the image, M87. It was in the news in April 2019 because the region around the supermassive black hole at its center was imaged for the first time. To put this image in perspective, that black hole image would occupy roughly 1/100,000 of a pixel in my image.
The arc of galaxies across the bottom is called Markarian’s Chain. It is named after an astronomer who was the first to realize they were gravitationally bound together. However, although M87 and Markarian’s Chain are the stars of this image (pun slightly intended), they have a large supporting cast. The image below shows just how many galaxies are really there.
Each of those circles represents a galaxy. On the full size image most of those circles actually contain a small, fuzzy blog. It’s a big universe!
This image included a lot of firsts for me. It was the first image taken with a mono camera and filters. It was the first to use an electronic focuser and rotator. It was the first time I combined data taken over two nights. However, it was not without its challenges. Though it is over two nights, it’s only 2.6 hours of data. Technical glitches limited the first night to an hour of data and the second night to 1.6 hours. On the third night, thanks to the help of a kind soul on the cloudy nights Internet forum I was able to make some major progress on one of my technical issues and collect more than two additional hours of data Even so, at only 4.8 hours there is a lot going on in the frame. These galaxies are on the order of 50-55 million light years away and many of the galaxies are elliptical. Ellipticals never have the kind of detail that spiral galaxies do and the distance hides what there is, but on the spirals in the frame a hint of structure is visible.
After looking at this for a while I became curious if the image contained any quasars. Back when they were first discovered it wasn’t known what a quasar was except that it was very distant and incredibly energetic. We’ve since learned that a quasar is an extremely energetic luminous galactic nucleus. The quasar can put out as much light as the rest of the galaxy combined. On my image they wouldn’t be more than dots but even imaging one would be pretty amazing. The software I used for the annotation above didn’t have a catalog containing quasars but I found and massaged a copy of the half million quasar catalog and made a new annotated image combining the quasar catalog with the galaxy catalog shown above. I wasn’t sure what to expect. I figured there might be a few candidates in the frame but, much as with the galaxy annotation above I was surprised to see this:
The white annotations are where a quasar is known to exist. At first I was disappointed. I wasn’t seeing anything in the crosshairs of all those white annotations. But, eventually I found one and by the time I was done I found eight (possibly nine) that seem likely to be quasars:
[table id=1 /]
The redshift value is a measure of how much the light has been shifted toward the red part of the spectrum. The larger this value, the further away the object is from us. The age value is a measure of how many billions of years ago the light began it’s journey to us. The catalog I used provided the redshift value (known as ‘z’) but the age values come from this website. It has a calculator where you enter ‘z’ and it provides a lot of information I’m not entirely sure how to interpret yet. My goal was to find the distance but the most relevant information I found was age of the universe at that redshift value. If I’m understanding it properly then age should be the distance of the object in light years at the start of its journey but I could be misinterpreting that.
If I’m interpreting this correctly and if I’ve used the catalog correctly then the most distant object on the image is 10.885 billion light years away (or was when that light started toward us). The actual spot on the image is barely a smudge brighter than the background. It’s not at all visually impressive but It amazes me that a small, 80mm refractor can capture light that is far older than our own sun’s age. More than twice as old.
Of course, I could have made a mistake somewhere along the line so I’m not certain of anything but so far I think I’ve got things right.
For comparison, the subject galaxies in Markarian’s Chain and M87 are in the range of 50 to 60 million light years distant. While that is incredibly far away it is a tiny fraction of the distance to those quasars, even the closest of them. I haven’t checked all the PGC galaxies but I’ve spot decked a few and they seem to range out to around two billion light years or so.
Spring is called “galaxy season” because the night sky is looking out of our galaxy making it the best time of year to observe the things outside the Milky Way compared to the rest of the year when our night sky is looking into our galaxy. However, for a small telescope like I am using, it is a challenging time of year because these are small in the frame. Fortunately, there are areas of the sky like this where the structure of the universe can be observed allowing us to see exactly how small a part of the universe we sit in.
Here’s a link to the image on astrobin.