The Supernova Remnant Challenge

by Jay Eads


If you want high-resolution finder charts for this article (and more), please check out the source article on Jay’s Astronomical Observing Blog!

Okay, it is evident if you search my blog that I do love supernovae. They are to me, the most fascinating subject because they not only signal the death of a star, but because they also signal how the universe continues to create new things from old. From Disney’s 1994 animated movie (great year, it was the year my son was born and a year after my daughter had arrived) the Lion King, some call this the Circle of Life. Items are created or living things are born, they live out a life, and then are recycled so that other things may be created, come into existence. We ourselves exist because of this cycle that exists in the stars. The iron in our blood, the calcium in our bones, the oxygen in our lungs, the carbon in our bodies are all elements made in stars or massive stars. Indeed, the only place that iron is made is in the core of a massive star and that signals the very death knell for that star when the core churns out iron.

So, to celebrate the roles that Supernovae play in creating the very elements that make up our earth and ourselves, I have decided to come up with a Supernova Observing Challenge. I hope you accept this challenge for the true joy in completing this challenge. I believe it is in observing the objects themselves or giving them a go that the greatest reward is found. Here is what equipment I would recommend.

1. At least a 10-inch dob. You can try it in a smaller one and I would be anxious to hear if someone does one or all of these in a dob smaller than 8 inches.

2. A good wide field eyepiece. For me this is the 31mm Nagler, 26mm and 22mm T4 Nagler and sometimes the 35mm Panoptic.

3. Also have two eyepieces that provide from 100× to 200× also as you will want to look at some parts of what you view with a little more magnification. For me in the 17.5mm dob or in the 24mm dob I would probably use the 22mm T4 Nagler and 10mm Pentax XW. Similar eyepieces can be used.

4. A 2 inch OIII filter and a 2 inch Narrowband filter, and have a 1 1/4 inch filter of the same types for higher magnification eyepieces. I have the Orion Ultrablock, the DGM OIII and NB, and the Thousand Oaks OIII and NB filters in these sizes to choose from.

5. The finder charts here or the ones I will link to and good transparent skies. It helps if you also can sketch an outline of what you’ve seen I think as part of recording your observation.

So what are the objects we are going after? Here is the list:

I have created a log book that I will attach or provide a link to my Google Docs where you can access it. Feel free to modify it as you wish.

1. Simeis 147 or Sharpless 2-240

First item up is Simeis 147. This is a faint supernova remnant in Taurus and Auriga, and you must not be faint of heart. It took me 3 seasons before I caught a wiff of this one. I have included an enlarged version of a star hop map by Reinar Vogel from his WebSite at this LINK. The finder charts come from his Sharpless Catalog, a free download and one I highly recommend LINK. Here are the finder charts for this object(s).

On the chart above it shows how to get to Al Nath in Taurus starting from Hyadum I and going to Hyadum II and then to Al Nath. From Al Nath you can do the star hops below to get to Simeis 147 and begin to explore the Supernova.

I labeled the star hops with red arrows so you can seem them better. In this LINK you can actually go and see a larger map of the Supernova, with the sections A, B, C, D, E that you can explore, with sections A &B being the easiest (still very hard) to see. This LINK shows a CDD Image by Steve Mandel and a sketch overlay by Rich Jakiel that is tremendous! That should help you to trace down this object. Oh, in Reinar’s Sharpless Catalog, on page 432 are the two charts above, and on page 433 is an image of the entire SNR so you can use that also to help

hop if you want to print them out.

2. Messier 1

The next object is Messier 1, the Crab Nebula. Here is the initial information from Wikipedia (LINK):

“The Crab Nebula (catalogue designations M1, NGC 1952, Taurus A) is a supernova remnant and pulsar wind nebula in the constellation of Taurus. It is not, as its name might suggest, in Cancer. The now-current name is due to William Parsons, 3rd Earl of Rosse who observed the object in 1840 using a 36-inch telescope and produced a drawing that looked somewhat like a crab. Corresponding to a bright supernova recorded by Chinese astronomers in 1054, the nebula was observed later by English astronomer John Bevis in 1731. The nebula was the first astronomical object identified with a historical supernova explosion.

At an apparent magnitude of 8.4, comparable to that of Saturn’s moon Titan, it is not visible to the naked eye but can be made out using binoculars under favourable conditions. The nebula lies in the Perseus Arm of the Milky Way galaxy, at a distance of about 2.0 kiloparsecs (6,500 ly) from Earth. It has a diameter of 3.4 parsecs (11 ly), corresponding to an apparent diameter of some 7 arcminutes, and is expanding at a rate of about 1,500 kilometres per second (930 mi/s), or 0.5% c.

At the center of the nebula lies the Crab Pulsar, a neutron star 28–30 kilometres (17–19 mi) across with a spin rate of 30.2 times per second,[6] which emits pulses of radiation from gamma rays to radio waves.”

Messier 1 is significant because as stated, it is the first object identified and linked to a historical supernova explosion. In addition we are seeing the remains of a Type II Supernova here, one that resulted from a star that according to “theoretical models of supernova explosions suggest that the star that exploded to produce the Crab Nebula must have had a mass of between 9 and 11 M☉ (solar masses).” As an amateur what is cool to me about this SNR, is one, the pulsar, and two, the fact that ancient Chinese and Asian astronomers, using math and recording their observations, provided modern scientists with the links and information needed to connect this to the 1054 A.D. supernova. That helped to move our knowledge of the Cosmos and of the Universe and Supernova along so that we can have the understanding we have today.

Here is an image taken by the Salt Lake Astronomical Society in 2009 using the Fawkes 1 Telescope out of Hawaii. You can see the pulsar in the center, there are two stars that are close together, the bottom one is more gray or bluish gray and it is the bottom one that is the pulsar. Also, if you look to the immediate right of the pulsar you can see two shock waves going out from the pulsar. You can also see one to the left going out in that direction as well. I can see in the gray mist/cloud the shape of the nebula I see visually when I observe this object with the added detail in there. Rather cool!

I will include two star hops and you can choose which one you want. Start at Zeta Tauri and work your way up to the stars on the curve left above. Then from the top star, the bright one, HIP 26272 goes up to that first group of zig zag stars and then over to the left to the second group. Follow the second group straight up to Messier 1.

This is similar but you go from the first curve set of stars, to a quadrilateral on its side to the bright star, up to Messier 1 that way. Rather easy to find and one to mark down.

To observe this one a medium to high power eyepiece helps and try a filter, both OIII, NB, and perhaps a light pollution filter if you have it. I have used my 7mm Pentax XW and my DGM NB filter and seen filaments so do something similar and see if you draw out the filaments in your observations.

3. IC 443 Supernova Remnant in Gemini

This is another winter supernova remnant, in the generally same area as Simeis 147 and M1. It makes sense to me to go for Simeis 147, then M1 then IC 443 as they rise in that order. When observing this one, aperture surely helps as does an OIII filter for the NE part and a Narrowband or UHC filter on the SW part. See how much detail you can tease out of this. It’s there, more than most will see but you have to be patient and dark adapted. Observe this one for a good long while before sketching or moving on.

Some information IC 443 or Sharpless 2-248; LINK: IC 443 (also known as the Jellyfish Nebula and Sharpless 248 (Sh2-248)) is a Galactic supernova remnant (SNR) in the constellation Gemini. On the plan of the sky, it is located near the star Eta Geminorum. Its distance is roughly 5,000 light years from Earth. Observing at Skyhound has a good article on IC 443 also at this LINK.

IC 443 may be the remains of a supernova that occurred 3,000 - 30,000 years ago. The same supernova event likely created the neutron star CXOU J061705.3+222127, the collapsed remnant of the stellar core. IC 443 is one of the best-studied cases of supernova remnants interacting with surrounding molecular clouds.The SNR optical and radio morphology is shell-like (e.g. a prototypical shell-like SNR is SN 1006), consisting of two connected sub-shells with different centers and radii. A third larger sub-shell, initially attributed to IC 443, is now recognized as a different and older (100,000 years) SNR, called G189.6+3.3. The remnant’s age is still uncertain. There is some agreement that the progenitor supernova happened between 3,000[3] and 30,000 years ago. Recent Chandra and XMM-Newton observations identified a plerion nebula, close to the remnant southern rim. The point source near the apex of the nebula is a neutron star, a relic of a SN explosion. The location in a star forming region and the presence of a neutron star favor a Type II supernova, the ultimate fate of a massive star, as the progenitor explosion.

Reinar agreed to let me use his charts so others can get interested and observe these fun objects! Here is his finder chart that I have made quite larger.

The one above and below are the same chart, close in, and the top one is simply telling you where to look for the SNR.

The image above is a more widefield shot I took from Starry Night Pro 6 to show IC 443 and how it sits in relation to Propus and M35.

Above is another shot of IC 443 from Starry Night Pro 6 with Eta at the end of the Constellation stick figure.

2MASS Atlas Image of IC 443. In this false-color infrared image, blue marks expanding gas where emission is dominated by excited iron atoms; the southern ridge (in red) is dominated by molecular hydrogen emission. In the image North is up, East is left. It is the blue segment of Iron molecules that are excited that you are going after and will use the OIII filter on. The Hydrogen needs the Narrowband filter and is hard to tease out as you must have very good skies that night.

This is from the NASA/WISE team capture of IC 443.This oddly colourful nebula is the supernova remnant IC 443. IC 443 is the remains of a star that went supernova somewhere between 5,000 and 10,000 years ago (they have narrowed down the time frame now). The blast from the supernova sent out shock waves that traveled through space, sweeping up and heating the surrounding gas and dust in the interstellar medium, and creating the supernova remnant seen in this image. What is unusual about the IC 443 is that its shell-like form has two halves that have different radii, structures and emissions. The larger north-eastern shell, seen here as the violet-colored semi-circle on the top left of the supernova remnant,(the one that you are going after here as the main part of your observation and responds well to the OIII filter) is composed of sheet-like filaments that are emitting light from iron, neon, silicon and oxygen gas atoms and dust particles heated by the blast from the supernova. The smaller southern shell, (needing the narrowband filter to bring out parts if your lucky and the sky is with you) seen here in a bright cyan color on the bottom half of the image, is constructed of denser clumps and knots primarily emitting light from hydrogen gas and heated dust. These clumps are part of a molecular cloud which can be seen in this image as the greenish cloud cutting across IC 443 from the north-west to south-east. The color differences seen in this image represent different wavelengths of infrared emission. The differences in color are also the result of differences in the energies of the shock waves hitting the interstellar medium. The north-eastern shell was probably created by a fast shock wave (100 kilometers per second), whereas the southern shell was probably created by a slow shock wave (30 kilometers per second). If you look at what a lot of astro-photographers capture and other images (Hubble) of IC 443/Sharpless 2-248, you see the Jellyfish structure that gives it its name. In this image by WISE, I think IC 443 looks much more like a Supernova Remnant. To be honest, in many Type II SNR’s I see many similar structures in them which raises questions but not for here.

I shared the following in my previous posts to show growth as a sketcher and I decided to share the three posts here to show this object sketched. The two sketches are rather different. The first shows the structure that I saw in IC 443 quite well and the second shows it in more detail with higher magnification. The first used both a wider field lens, the 27mm Panoptic I believe with the 14mm and 10mm Pentax XW and Type 1 Paracorr at the time. The second shows the 10mm and 7mm Pentax XW with the Paracorr. Finally I will add in the STSci Image here as I realized I use to do that all the time in my sketches and I think it brings merit. I believe if I recall, in the first sketch north is down and west is to the right.

Above is my first sketch of IC 443 and the one I like the best.

Second sketch is similar in direction but at higher magnification.

Above is the STSci Image of IC 443 showing the Jellyfish nature of the SNR. This image I really like for it shows clearly the brighter part of the SNR you want to go after. I am going to try to sketch the various parts and overlay them on this image. That will be a fun night of observing and challenging to see what I can see!

4. Barnard’s Loop Sharpless 2-276 in Orion.

I am including Barnard’s Loop because though old compared to us, it is most caused by winds of massive stars in Orion blowing stellar winds out or by Supernova’s that exploded and created the bubble. Discovered in 1894 Barnard’s Loop (catalogue designation Sh 2-276) is an emission nebula in the constellation of Orion. It is part of the Orion Molecular Cloud Complex which also contains the dark Horsehead and bright Orion nebula. The loop takes the form of a large arc centred approximately on the Orion Nebula. The stars within the Orion Nebula are believed to be responsible for ionizing the loop.

The loop extends over about 600 arcminutes as seen from Earth, covering much of Orion. It is well seen in long-exposure photographs, although observers under very dark skies may be able to see it with the naked eye.

Recent estimates place it at a distance of either 159 pc (518 light years) or 440 pc (1434 ly) giving it dimensions of either about 100 or 300 ly across respectively. It is thought to have originated in a supernova explosion about 2 million years ago, which may have also created several known runaway stars, including AE Aurigae, Mu Columbae and 53 Arietis, which are believed to have been part of a multiple star system in which one component exploded as a supernova.

Although this faint nebula was certainly observed by earlier astronomers, it is named after the pioneering astrophotographer E. E. Barnard photographed it and published a description in 1894.

So though not a specific supernova remnant like the other objects here, it is a fun, challenging object to go after in the cold of winter. I want to give it a go with one of my refractors, if not both and see what comes up this winter. Stephen Waldee in his web page as a great article on his observation of Barnard’s Loop, and shares the brightest part that he focused on at this LINK (about 1/3 of the way down the page). Here are the finder charts I gathered and enlarged from Reinar.

The above image shows the Orion Complex with Barnard’s Loop on the left, and agreeing with Stephen Waldee, Reiner V. has circled the part of Barnard’s Loop most easily visible. Can you identify before looking at the next image the Flame Nebula, B33 The Horsehead Nebula, Messier 42 and 43 and the Witch’s Nebula?

There it is all labeled, and I hope correctly.

Above is a broad, wide version of the finder chart.

Here I have labeled on the finder chart where both Mr. Waldee and Reiner say is the easiest part of Barnard’s to see.

Here are Reiner V.’s notes for you to use.

A close up of the images so you can see more of the region (I have removed the bottom portion).

Above is the shorter finder chart as well. I have all of these available and will be uploading them AFTER the month’s new moon (maybe this weekend, we’ll see) into a booklet to download but you’ll have to get them off my Google Drive.

5. Veil Nebula

Well now we leave the confines of winter and move to summer to observe two similar SNR’s that are in the same constellation of Cygnus the Swan. The first is the ever well known and well observed Veil Nebula. Veil Nebula is made up of NGC 6979, NGC 6960, NGC 6992, NGC 6995, and other parts. Here is a decently recent NASA image of the Veil Nebula that has its various parts labeled and identified.

What is interesting to me, is that in looking online for over two hours, I found spots and pieces, professional articles but not a lot on this tremendous object. Most of us have looked at NGC 6960 and NGC 6995 in our telescopes. I encourage you this time not to rush your observation, but to really study the details and seek out the parts that you haven’t seen or studied before. Pickering Triangle sticks out for me as a place to go and really study as does NGC 6979 and NGC 6974. This LINK to J P Metsavainio work shows Pickering’s Triangle with detail and this LINK to his page will blow you away. Finally I love his animated view of the entire Cygnus Loop in this LINK over on his YouTube channel. For me personally, I need to view the Southeastern Knot and I need time studying IC 1340 (I have observed both of these before) and Pickering’s Triangle. You’ll need to determine your goals on these objects.

Here are two quick finder charts in case someone doesn’t know how to spot the Cygnus Loop.

6. Sharpless 2-91 in Cygnus

This is a SNR that isn’t as well known as the Veil Nebula/Cygnus Loop. However, it is very similar and it is older and a good challenge. Reiner Vogel over on the Deep Sky Forum has a wonderful post about this object there LINK. This LINK will share Steve Gottlieb’s observation of this object fourteen years ago in 2001. I’ve posted this before but this LINK to Sky & Telescope’s article on viewing this other Veil Nebula provides good insights and good links also. Adventures in Deep Space at this LINK has observations by Jim Shield and details on observing this complex. .

I have observed this myself several times now, and have sketches located on my blog here back in August 2013 for the first time LINK (last object at the bottom of the post). I know from experience this is a fun bugger to chase down and filter and aperture make the difference when combined with the right atmosphere.

So how to get there? Go to Alberio and then work your way up to 9th Cygni. Here are the finder charts thanks to Reiner.

In the finder chart above, Alberio is that bright star at the bottom, B 2 for beta 2. Go up as I said to 9th Cygni and you’re right in the middle of one of the brighter parts of the SNR.

The finder chart above gives you a better overall view of the SNR and how to navigate which is not an easy task with all the stars that are present here. Don’t forget to put the map as your reflector or dob or SCT or whatever instrument you use to see this.

Here I took Reiner’s finder chart and enlarged it so that you can really see where the brighter filaments are and where to navigate to see them. Check out Jim Shield’s link above for more information. Personally I need to do more than just go after 01 and 02, I need to actually take an evening and find out how much of this SNR I can really see. I would LOVE to do a sketch like the one above for Simeis 147 where I put an overlay on a photograph for this object(s). That is a very worthwhile sketching goal. So see what you can see here!

7. Cassiopeia A

UPDATE: 12/8/24: I wanted to update this and share the Webb Website called Take a Tour of Cassiopeia A – LINK.

This is a unique supernova remnant and I have observed it before LINK (sketch and observation at the bottom of that post). In truth, it is my desire to observe this object again this fall that made me put this post together. To be truthful, this is my major sketching project over the next year or so (as I observe my Herschel 2500 and sketch them as well) that I want to make a compilation of to submit for publication. I think that will make a good adventure, observing the visual SNR of the Milky Way. Anyway, Cassiopeia A is observable and Sue French in the December 2013 Deep Sky Wonder column discusses it.

Deep Sky Forum at this LINK by Howard has a wonderful entry of his observation of Cassiopeia A of the main arc. I also as in my post above captured that but Howard mentions going after the southern arc and that is something worthy to emulate. Howard states there (and please read his entire post, it is worth it) “ Cassiopeia A is plotted in Uranometria (page 18). I’ve found that star hopping from M52 to the Bubble Nebula (NGC 7635) and then along a ragged line of faint stars to Cas A is a relatively easy way to get to the right spot.

To see what Cassiopeia A looks like photographically, James Webb Telescope along with the Chandra telescope link up to provide this view and the corresponding article at this LINK. Scroll over the image and a circle will go around it. If you look carefully you can see the southern arch of the SNR. Okay, lots of star hops views coming up.

The plate above shows the field of Cassiopeia A in a somewhat wide field. You can see Cass.A in the middle and if you look, you can see the southern arc.

In the plate above I have labeled the triangle that I use to find Cassiopeia A and then circled the part of Cassiopeia A I can actually see, the arc that is.

In the plate above here is a closer view of Cassiopeia A with its northern arc showing nicely and the southern arc is in view here.

The image is same as above but labeled so you can identify the parts of Cassiopeia A

Here come the wide field finder charts. I have included the original above, and then the next one is blown up so you can identify parts more. Let me state to find Cassiopeia A you may need to use a combination of these images to get there.

The finder chart labeled here is ONE WAY, not the only way to get to Cassiopeia A. You will see in the Starry Night Images below that you can get to M52 and then hop right down to it.

This is the close in finder chart for Cassiopeia A.

I have labeled how I star hop to Cassiopeia A and then use the images above to complete my hop to this fun object.

Starry Night 6 I use somewhat (Sky Tools 4 is my main astro software) but here it is decently effective. Please note you just need to Star Hop to Messier 52 here. Also, Tycho’s SNR is labeled here but DO NOT try it. This links answers the question if parts of SNR 1572 are visible LINK. Right now, no but then again, neither was Cassiopeia A in the past. North is to the left, south is to the right, east is up, west is down in the Starry Night 6 images.

Repeat

Let me point out that Cassiopeia A may be this bright and big but you are not going to see that bubble or that much of it. You are going to see an arc or two if you’re lucky (the northern arc should be somewhat easy).

Here I have labeled the key parts to this star hop. How you decided to go from Messier 52 to the triangle is up to you. Once at the triangle you should be able to get it with these and the images above. Let others know how you did with this. Remember a dark site, clear transparent skies and aperture help to nail this one.

Finally, here is the STSci Image of Cassiopeia A. You can see the ring in this image easily.

8. Abell 85 / CTB 1 or SNR G116.9+00.1 in Cassiopeia

Isn’t it funny how these SNR tend to group together in the plane of the Milky Way? I mean look, Auriga/Taurus, Taurus, Orion, Gemini, Cygnus, Cygnus, Cassiopeia, Cassiopeia. I would throw in SNR 1006 in Lupus but I haven’t read if that is doable though I doubt it. Perhaps in time. Abell 85 or CTB 1 is one of the most difficult objects to observe. It is close to Simeis 147 in seeing it and don’t get discouraged. It just may take more than one night, with conditions coming together along with everything else to nudge this one out. Check out this LINK in Sinbad to see how faint this object is but don’t scroll over the image or you will need to refresh as you’ll change locations!

Here we go. Abell classified it as a Planetary Nebula at first, but in time it became quite evident this is a Supernova Remnant. It has very faint HII and OIII lines and thus one reason why those filters just don’t always help on this object. My take and I haven’t done any studying on this object yet, is that the star was very large and shed off via a stellar wind much of its oxygen layer (and hydrogen and helium layer) before going supernova. You can do a Google Search for (in this order) CTB 1 Abell 85 and get lots of information and color images. I think on this faint SNR though, I like it in black and white as the contrast really comes out. See this LINK to see if you agree. Richard Murray imaged it and has a quick write up on it at his blog at this LINK. Rich Jakiel describes his visual observation at this LINK. Finally J.T. Metsavaiani (showed his stuff under the Veil Nebula and Cygnus Loop) has a wonderful set of images (though we will not see this visually) on his blog at this LINK.

To get there here are the finder charts.

Above is the wide field view of CTB 1 or Abell 85. The bright star at the bottom of the image is 9 Cass.

In the image above you can see a wide field view on the left, and a closer image on the right.

Above is the wide field finder chart for CTB 1 or Abell 85. Caph is the starting point up to NGC 7790 and up from there.

Here is the wide field chart again, zoomed in so you can see my star hop to this object.

This is the zoom in finder chart. If you use a good image of CTB 1 you can see where the SNR filaments are. Get to NGC 7790 on your star hop then use this chart to hop up to CTB 1 or Abell 85.

This chart is important as I have roughly lined in where the brightest and most likely to visually see/observe the filaments to this SNR are located. Hope this helps and feedback or corrections are welcome. Remember on this one, aperture and you can try the OIII filter or other filters but most visual observers share the fact that they don’t really improve the image though one said the OIII darkened the image (as it should) but brought out the filaments a little more.

The wide field map from Starry Night Pro 6. It may help but I think the charts above are excellent so those are the ones to go with. I can’t wait to give this one a go real soon!

Well there you go. 8 SNR objects or related to an SNR in some way in the case of Barnard’s Loop. I hope some of you give this a go and let me know how your observations of these objects go. I am sorry I have no reward other than the fun, frustration, and the challenge of seeing some of these faint SNR that exist in our own Milky Way Galaxy. Perhaps in what remains of our short lives we will have the opportunity to see a bright supernova that will create a SNR for our descendants to view one day! Enjoy the wonders of the night sky!