August 2019 - Picture of the Month
NGC 6894 in Cygnus
It's been a while since the last planetary nebula so that's what I decided to go looking for this month. I think I found a really good one.
NGC 6894 caught my attention due to its wealth of internal structure. But this planetary is particularly interest to me due to its interaction with the interstellar medium (ISM) also captured here.
Bernhard Hubl also does a great job of capturing it in one of his images, but Adam has access to a really large telescope that yields both detail inside the planetary nebula and the ionisation nearby very clearly.
Bernhard refers to a paper that suggests that those stripes to the upper right comprise material ionised by the central star of NGC 6894 that's been stripped by the ISM, and that their form is indicative of the Milky Way's magnetic field. This is broadly supported by a later paper published in Astronomy and Astrophysics.
The Night Sky Observer's Guide (NSOG) Volume 4 suggests that NGC 6894 can be seen with a 20-cm telescope. It's bright, but it's also fairly large, which isn't a great combination from less than excellent skies. George Kepple suggests that a large scope can show detail. Perhaps unsurprisingly no mention it made of those nebulous stripes.
James Whinfrey - Website Administrator.
