[Prev][Next][Index][Thread]

Re: (IAAC) IC 434 - 17.5inch F/4.5



Again thanks for these fine observations, Yann. BTW, bravo on catching
the single useful hour of darkness between moonset and dawn yesterday!
Also, I was curious about IC 466 - you mention it contains both refl-
ection and emission features, and yet its appearance only changed at
the very edge when using emission-band filters. What can be concluded
about the physics inside this nebula from this visual effect?
And now for the Dumb Amateur Astrophysics Question of the Week...
I have always been curious as to the astrophysical explanation behind
the narrow H-beta emission spectra of a few certain nebulae in the sky:
these include the "H-beta four" nebulae which traditionally justify the
use (and so purchase) of an H-beta filter versus an OIII or UHC. Why do
these nebulae (e.g., IC434 around the Horsehead, or the California) emit
so exclusively and narrowly in the Hydrogen beta band?
Lew
To UNSUBSCRIBE from the 'netastrocatalog' lists, use the Web form at:
http://www.tiac.net/users/lewkaren/netastrocatalog/subscribe.html

Follow-Ups: References: