Looking for more obscure objects again. This is a young star forming region, contains masers too. Very close to the Bubble Nebula but just across the constellation boundary in Cepheus. In the Perseus arm of the Milky Way.
Cepheus near the border with Cygnus. Bright Moonlight causing some background gradients.
NGC 6939, discovered by William Herschel of course, is quite old for an Open Cluster, between 1 and 1.3 billion years. It also lies about 400 parsecs above the galactic plane, a little unusual for Open Clusters as they are usually within the plane of the galaxy, hence the alternative name of Galactic Clusters.
NGC 6946 (also discovered by William Herschel) is about 25 million light years away and resides in the Virgo Supercluster. It’s known as the Fireworks Galaxy because it seems to be a hive of supernovae; ten have been observed in the 20th and 21st centuries alone. This is about 10 times the rate observed in our own galaxy, even though the Milky Way has twice as many stars. In fact more supernovae have been observed in this galaxy than any other.
During 2009, a bright star within NGC 6946 flared up over several months to become over one million times as bright as the Sun. Shortly thereafter it faded rapidly. Observations with the Hubble Space Telescope suggest that the star did not survive, although there remains some infrared emission from its position. This is thought to come from debris falling onto a black hole that formed when the star died. This potential black hole-forming star is designated N6946-BH1. The progenitor is believed to have been a yellow hypergiant star. Wikipedia
A planetary nebula with a diameter of 1 ly and about 200 ly away (Wiki says 2800 but parallax says 15.7mas ~200ly). Another William Herschel discovery. You can see the central star is still quite bright but is now a cooler white dwarf. There’s a nice double star system just top right of the nebula, although I suspect from their parallaxes (2.13 mas and 1.97 mas) it’s not a binary system. The nebula is much closer with a parallax of 15.7 so not associated with the double star.
Bringing out the all the dusty, dark material leaves me with a horrible background.
Iris Nebula NGC 7023 / C4
2020-09-19 Mag. 6.8
250mm f4.8 Newtonian, MPCC
QHY168C @15°C 2/20 gain/offset IDAS P2
28x180s 10/50 darks, flats, bias
The Iris Nebula is a bright reflection nebula in the constellation Cepheus. The designation NGC 7023 refers to the open cluster within the larger reflection nebula designated LBN 487. The nebula, which shines at magnitude +6.8, is illuminated by a magnitude +7.4 star designated SAO 19158. Wikipedia
New camera testing. Different way of working with Gain and Offset needing to be chosen and probably using more shorter exposures than the CCD. 32Mb lights instead of 10Mb for the CCD means much longer processing in APP. Couldn’t use the flats as I moved the camera between flats and lights.
NGC6992 Eastern Veil Nebula
Mag. 7, Size 3°
250mm f4.8 OO Newtonian MPCC
QHY168c @-15°C Gain/Offset: 10/50 (unity) No filters
Imaged areas around this a lot for HOYs but never this actual part. First time back using the MPCC without the LP filter this time to avoid internal reflections. Stars are better at 3 corners but top right still off – probably focuser alignment.
A by-product of doing HOYS-CAPS data for V1490Cyg in Tri-colour R, decided to make a stacked image out of it. 30 subs over 6 months.
At least 4 Herbig-Haro objects imaged in this and marked out in the greyscale version.
IC 5070 Pelican Nebula
Cygnus Mag. 8, 60’x50′
250mm f4.8 Newtonian
DSS, Nebulosity, Photoshop
“The Pelican is much studied because it has a particularly active mix of star formation and evolving gas clouds. The light from young energetic stars is slowly transforming cold gas to hot and causing an ionization front gradually to advance outward. Particularly dense filaments of cold gas are seen to still remain, and among these are found two jets emitted from the Herbig–Haro object 555. Millions of years from now this nebula might no longer be known as the Pelican, as the balance and placement of stars and gas will leave something that appears completely different.”
“Herbig–Haro (HH) objects are bright patches of nebulosity associated with newborn stars. They are formed when narrow jets of partially ionized gas ejected by said stars collide with nearby clouds of gas and dust at speeds of several hundred kilometers per second. Herbig–Haro objects are ubiquitous in star-forming regions, and several are often seen around a single star, aligned with its rotational axis. Most of them lie within about one parsec (3.26 light-years) of the source, although some have been observed several parsecs away. HH objects are transient phenomena that last around a few tens of thousands of years. They can change visibly over quite short timescales of a few years as they move rapidly away from their parent star into the gas clouds of interstellar space (the interstellar medium or ISM). Hubble Space Telescope observations have revealed the complex evolution of HH objects over the period of a few years, as parts of the nebula fade while others brighten as they collide with the clumpy material of the interstellar medium.”
Sh2-155 is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. It is widely known as the Cave Nebula. Sh2 designation because it’s part of the Sharpless Catalog (1959) of 312 HII regions. About 2400 light years from Earth and a stellar nursery.
Narrowband filters really do cut through the murky, light polluted skies of Edinburgh so well. Obviously false colour, has to be for narrowband, but can’t decide which is the best so two different tone mappings: SII Ha OIII -> RGB and Ha OIII SII
Been meaning to do this one for ages. Not easy because the background gas and dust can be easily lost in the light pollution and noise.
“The Iris Nebula, also known as NGC 7023 and Caldwell 4, is a bright reflection nebula and Caldwell object in the constellation Cepheus. NGC 7023 is actually the cluster within the nebula, LBN 487, and the nebula is lit by a magnitude +6.8 star, SAO 19158.” Wikipedia