I would have to say this is a reflection nebula due to the fact that a UHC filter tames it down rather than increases contrast. Also in photographs it comes out as blue, meaning the colors except blue are absorbed in reflected starlight. Many nebulae are a combination of types, and 1788 may be emitting some small amount from hydrogen or oxygen excitation, since there are hot stars in the vicinity, and remember the center was somewhat luminous in the UHC. I think in an effort to more easily classify nebulae, astronomers have invented this lumping terminology such as diffuse, bright or galactic to be inclusive of the various types. Descriptive terminology knows no bounds, however, so spanning 3 food groups is piece of cake. Jack > Is it possible that NGC 1788 is both a Reflection and an Emission Nebula? > In that case wouldn't it still show a little of it's nebulosity with a UHC > filter? > > Is it really possible for one deep sky object to be included into 3 food > groups? > > ~Jenn, TP > --- This message is from the AZ-Observing mailing list. If you wish to be removed from this list, send E-mail to: AZ-Observing-request@xxxxxxxxxxxxx, with the subject: unsubscribe. The list's archive is at: //www.freelists.org/archives/az-observing This is a discussion list. Please send personal inquiries directly to the message author. In other words, do not use "reply" for personal messages. Thanks.