High in the sky on summer evenings is the constellation Cygnus the Swan. Cygnus lies in the foreground with the Milky providing a dramatic backdrop when viewed from a dark sky location. Additionally there are a number of spectactular Hydrogen-Alpha nebula in the area making the Cygnus portion of the sky one of the favorites for astronomers, both amateur and professional to explorer.
One of the showcase objects in this area is the Veil Nebula, a large supernova remnant created by massive explosion of a star some 10,000 years ago (more on that below). Think of the most massive stellar explosion you have seen in any movie and multiple it by 100. Although the star that generated this explosion was about 1,500 light years from earth the explosion could have been seen in the daytime sky by early men who lived just beyond the edge of recorded history.
The overall Veil Nebula is huge. It covers an area of the sky just off the western wingtip of Cygnus and covers an area 3 degrees across (the equivalent of 6 full moons wide). I have imaged the two principle parts of the Veil in the two images here. The western Veil (with the naked eye visible star 52 Cygni seemly embedded in the nebula. Actually the star isn’t associated with the nebula, it is simple in the same line of sight.
The glow that makes up the overall Veil Loop is made from excited Oxygen III (blue) and Hydrogen-Alphas (red) gases. Because the Veil Loop is positioned in the line of sight of the Milky Way galaxy we see many more stars in these too images that we see from other nebulas that are not in the line of sight of the Milky Way.
How Old is the Veil Nebula?
This is an interesting question. I have seen references that range from as young as 5000 years old to well over 50,000 years from some older sources. Most modern sources put the age as anywhere from 5,000 to 20,000. The Hubble Telescope website puts it as 5,000 to 10,000. To my way of thinking it must be closer to 10,000 rather than 5,000.
So why do I think that the Veil Nebula probably not as young as 5000 years? Because if the Veil were that young there is a fair chance that we would find evidence of the explosion in ancient recorded history and no such record appears to exist. Here is the logic: If the Veil was only 5000 years old then the initial blast that created the supernova remnant would have reached earth about 3000 years ago. That blast most likely would have been brighter than all the combined light of all the stars in the Milky Way. It would probably been visible in the day and certainly would have been a spectacularly bright object in the night sky for weeks or even longer. That’s the stuff that make for the great stories that get passed down in oral histories to eventually be recorded. The beginning of written records in the western world took place about 3200 BC. Not only would the explosion have occurred after writing was created, as said, the event might well have created a oral history later to find its way into a written record. No such evidence has shown itself therefore I am thinking it more likely that the event occurred thousands of years later. I would love to hear anyone that can add to this discussion with information I have not found. One argument against my position is that the earliest writings were tabulations of inventories of grain and the like. I am not sure how much later true recording of events came in.
One final note, without going into detail the above speculation has been rewritten based on some clarifications about what astronomers mean when an astronomical event occurred at great distances (The Veil Supernova remnant is 1500 light years from earth). If you care to peruse that discussion follow this link: http://tech.groups.yahoo.com/group/ocastronomers/message/5709
Knock Your Socks Off
While everything we are looking here is based on viewing the Veil Nebula in photographs, my most vivid memory of viewing the Veil Nebula (the western portion) was when I took an OIII filter (Oxygen III) and put it in from of an eyepiece in my 18″ dobsonian style telescope in the late 1980’s and saw the Veil thru the eyepiece. I was standing on a one step stool to see the view and it was so dramatic that I lost my footing. For those of you that are not regular amateur astronomers let me share with you a known fact, while it is very cool to see great images of nighttime wonders like the Veil Nebula in photographs here, there are many many of these objects that will deeply affect you when you see them directly through an eyepiece. The views won’t be in color or as bright, but there is something magical that happens when your eye and brain sees these views directly. Next time you go to a star party ask if the Veil Nebula is up and could you see it through an OIII filter. You won’t forget the experience.
Data applies to both images. 36 1-minute exposures in LRGB for each image. Stacked in MaxImDL and processed in Photoshop CS5. Celestron EdgeHD 14″ with Hyperstar lens giving f/1.9. July 20 (eastern) and July 21 (western), 2012. By Russell Sipe. Many thanks to Sam Saeed who is coaching me on some basics of Photoshop editing of astrophotos.