I have imaged LBN 468 and Gyulbudaghian's Nebula (PV Cephei = HH 215)
on two occasions: Last year, on Aug. 7, 2010, and this year, on May 27, 2011.
For the first I used the 2.8-8 ED version of the Powernewt, with a SBIG 8300C,
and for the newer one I'd used the Powernewt's Carbon-Fiber version (2.8-8 CF)
and a SBIG 8300M.

Two days ago, I presented the two images (old and new) on these sites,
calling attention to the changes in the nebula: (citing myself) Finally,
upon comparing this image to the one I shot back in Aug. last year, the
shape of PV Cephei had CLEARLY changed, and the very focused beam of
last year has given way to only the broader part of the jet this year…
To me, it's really breathtaking to see changes in a DSO take place over
the course of less than one year… Here's the new image (Powernewt and
8300M w/Astrodon Gen II filters):
http://www.pbase.com/boren/image/137767256/original
… and here's last year's (still shot with my old 8300C):
http://www.pbase.com/boren/image/128919087/original

Invaluable comments made by Bob Frank on the SBIG forum, and a note made
by Neil Heacock on the DSLR forum, called my attention to two passages
published on the net, referring to the "jet" seen in my 2010 image, as a
phenomenon seen last in 1952:
http://www.weblore.com/richard/diappearing_nebula_-_pv_cephei.htm
and
http://observing.skyhound.com/archives/oct/GM_1-29.html

So… I cut and paste into the shown here - both processed versions and near
raw stacks of both images (the near raw ones are full stacks, upon which
the only processing was digital development, slight low-pass filter, and
levels to set the black point).