Nebula Challenge No. 1
The Homunculus Nebula
The massive nebula complex of Eta Carina gets its name from the star Eta Carina. As I mentioned earlier, this star is in its death throes. Having exhausted its fuel, it is in its final stage of its existence as it struggles to maintain that fine balance between the energy output and its massive gravitational pull upon itself. In a way, it is having fits and spasms as this supermassive star stuggles to keep itself going. And eventually, the energy output of the core won't be able to resist the massive crush of the main body of the star, the star will then collapse on itself, and this monumental implosion will result in one almighty supernova explosion.
But for all this drama, what is most fascinating about the star Eta Carina is this very pre-supernova stage that it is currently in. These jitters and spasms at one time saw Eta Carina as the second brightest star in the sky around 150 years ago - which most likely wasn't Eta Carina itself throwing this massive wobbly, but its invisible binary companion that had its own fit of blowing material it has absorbed from its supermassive parent. The material that's been ejected by Eta Carina we can actually see through even modest scopes. AND then, the complex gravitational and magnetic interplay between these two stars has sculpted this cocoon into a most gorgeous bipolar nebula - the Homunculus Nebula.
For all the terrifying violence happening with this supermassive star, the Homunculus itself is only a very small structure within the giant Eta Carina Nebula complex. It is no larger than Saturn through a scope. But its delicate double-lobe structure can be seen even in small scopes. When you first look at Eta Carina, you will first notice its distinct red colour. You will then notice that it is somehow fuzzy, curiously "resisting" to come to focus. But this is because of the influence wee bipolar nebula.
The Challenge
This is one challenge that will test your visual acuity, your patience, your scope, seeing and transparency, and depending on your scope the need for a dark sky or an urban sky this is possible.
As the Homunculus is a small sucker, you will need to ramp up the magnification, and thankfully it takes magnification very well. How much magnification depends on your aperture.
The first part of this challenge is to identify the two lobes. You will see one love quite clearly, the one that points more towards us. The second lobe points away, and it is a little dimmer. The lobes themselves show a fine, very delicate, almost filigree structures within them. Identifying the individual lobes and their striated structure is the first part of this Challenge.
The second part is identifying the most illusive and yet striking third structure of the Homunculus - the skirt of material that fans out between the two lobes, somewhat like a ballerina's tutu. It was the unexpected spotting of this skirt just last week that not only left me gasping with amazement, but is also the inspiration for this challenge. This skirt I had only ever seen in Hubble photos of the Homunculus, and never, EVER expected that this skirt was even a visual possibility! Yet there it was, plain as day!
Note that the skirt is a most illusive structure. While seeing the two lobes is relatively easy, the skirt is another matter altogether. Seeing conditions, transparency, visual acuity, scope quality, all coming into play.
I saw it through a 10" scope from an apartment block rooftop from inner Sydney. I didn't have my sketching materials with me as I wasn't expecting to see anything so breathtaking. I'm glad that I didn't have them either as I would not have been able to reproduce the Homunculus with the necessary colour.
However, this vista was the necessary inspiration for me to raid my other kit of soft pastels to have a practice at reproducing what I saw through the eyepiece. The sketch below is the test piece I did, attempting to emulate the various structures and colours that I saw, including the skirt.
,
Happy hunting!
~x.X.x~
This test sketch also gives an insight to how I work. I often practice my sketch technique, not only to keep in touch with it, but to experiment with new ideas and trying different techniques and also following up inspirations that have pricked my attention and curiosity. These inspirations can be anything, from cloud formations to the drawing done by a little kid, and then trying to work out how to adopt that effect into my sketching repertoire. Trying these things out at the eyepiece is neither the best place nor where to experiment - the eyepiece is where you need to be confident with your technique, and concentrate wholly on the task at hand.
Alex.
EDIT: I've reloaded the sketch pictures because for some reason they didn't show up in the first instance.
Alex.