... unlikely pair of stars may have created an oddly shaped, gaseous nebula that resembles an hourglass nestled within an hourglass ... Images taken with Earth-based telescopes have shown the larger, hourglass-shaped nebula. ...
2. http://www.mso.anu.edu.au/annualReport/1999/annualrep1999.pdf
... Scowen, P.A., Hester, J.J., Evans, R.W., Ballester, G.E., Clarke, J.T., Crisp, D., Griffiths, R.E., Hoessel, J.G., Holtzman, J.A., Krist, J., and Mould, J.R., "The Etched Hourglass Nebula MyCn 18. ...