The most famous and best understood of these enigmatic jewels is Hubble's Variable Nebula
(NGC 2261), which is the peculiar nebula associated with R Monocerotis (R Mon).
Speakers in the morning were Nick Hewitt, 'Barnard, Gordon and the darkness', Paul Curtis, 'Deep Sky imaging and processing using a modified DSLR', and Gary Poyner, with an update on a joint Deep Sky Section and Variable Star Section project to observe RR Tau and its associated variable nebula
Known as Hubble's Variable Nebula
, or NGC 2261, it displays a reflecting comet-like nebula with R Monocerotis at the southern tip.
Continuing in Monoceros, turn south for a degree to find a small, bright, and interesting nebula, NCC 2261, also called Hubble's Variable Nebula
. At times, the little cloud appears slightly dimmer or brighter, and its shape will change between observing sessions.
Variable stars are not uncommon but here we have one, accompanied by a very special object: NGC 1554/55 possesses a variable nebula
that makes the combination outstanding.
For more of a challenge, NGC 1555, better known as Hind's Variable Nebula
, is an interesting object.
It was about 1' across when I viewed it, but NGC 6729 is a variable nebula
much like the celebrated Hubble's Variable Nebula
(NGC 2261) in Monoceros.
The Variable Nebula
Project under the direction of Grant Privett continues.
This wide-field image of northern Monoceros includes the Cone Nebula, Hubble's Variable Nebula
, and the open cluster Trumpler 5 at right.
These were Hind's Nebula (NGC 1555) in Taurus; Hubble's variable nebula
(NGC 2261) in Monoceros; NGC 6729 in Corona Australis; Gyulbudaghian's nebula, discovered in 1977 neighbouring the variable star PV Cephei; and McNeil's Nebula in Orion, recently discovered in 2004 January and thought to be associated with the infrared source IRAS 05436-0007.
Turning to variable nebulae, the Director opened with a pair of images of Hubble's variable nebula
, taken by Nick James in 2010 March and Maurice Gavin in 2010 November, which showed clear changes to the structure of the nebula over those eight months.
NGC 2261, also known as Hubble's Variable Nebula
or Caldwell 46, is a remarkable object lying 1.2[degrees] south-southwest of 15 Monocerotis.