Orion widefield: click to enlarge NGC 1981 open cluster and NGC 1977 running man reflection nebula: click to enlarge NGC 1977 running man reflection nebula: click to enlarge.
I have waited SO long for a clear night and at last it came! Orion is now low in the sky so this was my last chance to image these targets for this year. Set up as usual and wasn’t sure if I had a great polar alignment – also, the Orion nebula is so bright that long exposures burn out easily so I chose 2 minutes as a good compromise. I was keen to use “dithering” with my auto-guider as it is said to reduce noise and bring out subtle detail – seemed to work very well. Am also now using “Neat Image” anti-noise software which has made a big difference.
Although it doesn’t look like much, I am very fond of open cluster NGC 1981 as it is the first object I looked at in a star atlas then decided to try and find with my telescope (a 8.75 inch Dobsonian). My old sky diary from 2009 is here: http://www.johnapurvis.synology.me/sky_diary.html
480/80mm refractor. Canon 60Da at ISO 800, 14 x 2 min sub-exposures. Astro-Hutech LPS filter. Ioptron ZEQ25GT mount. SSAG/PHD auto-guiding/dithering (dithered: every sub at 2 pixels). Focusing and camera sequencing/control with BackYard EOS. 30 darks and 25 flats (white LED panel: 1/20s @ ISO 800).
Post-processed in PixInsight 1.8 and Photoshop CC 2014. Noise reduction with Neat Image.
In the November 2013 edition of Sky and Telescope magazine, Alan Whitman mapped out structures within Andromeda that he has observed with his 16-inch Newtonian and a colleague had observed with a 12.5 inch Newtonian scope.
Whitman A. Going Deep: Exploring Messier 31. Sky and Telescope 2013; Nov: 58-61.
Newtonians are famous for being able to grab lots of light and resolve at high magnitude but long exposure astrophotography gives you a chance to catch up. The first page of the article is a black and white photographic negative of Andromeda that has been labelled with all the globular clusters (G designation), open clusters (C designation) and stellar associations (young, star-forming regions, A designation) that the pair have observed over many years.
I have used their map to construct my own based on my 115 minute integration with just a 71mm scope and have labelled everything that I could match on their map with my own.
These black and white negative “plates” are interesting because this is how Astronomers in the 1920s, such as Edwin Hubble explored the Cosmos. One of Hubble’s smartest moves was to hire the best photo technician and developer that he could get so that his plates were of the highest quality.
I will post my full map as soon as it is complete but here is a close up for now:
G = globular cluster (located immediately to left of letter “G”).
C = open cluster(s) (located immediately above or below letter “C” OR circled if close together).
A = stellar association (circled).
I am just amazed that I can locate globular clusters around a galaxy 2.5 million light years away with a 71mm scope in my back garden!
Click to enlarge image
This immense emission nebula comprises hydrogen gas excited by UV light from nearby star Deneb. It bears a resemblance to continental North America and covers such an expanse of the sky that the Moon would fit into the “Gulf of Mexico”. Open clusters Collinder 428 and NGC 6997 are marked. The denser area of HII towards the bottom is known as “the wall”. Just beside it is an obscuring patch of dust and cold gas, dark nebula LDN 935.
This object is very difficult to see with a backyard scope in a light polluted town but photography really helps it stand out.
Taken during 26th August session.
12 x 2 (24 min integration) min exposures. 480/80mm f6 refractor with 1.0x field flattener. Ioptron ZEQ25GT mount.
Canon 60Da DSLR @ ISO 1600 with Astronomik CLS filter. Acquired with Backyard EOS and guided with Orion SSAG Autoguider/PHD software. Processed in Pixinsight 1.8 and Photoshop CC.
Click to enlarge image
This pair of open clusters together make one of the classic targets to see in binoculars or a small telescope. Number 14 in the Caldwell catalog.
Taken during session on 26th August 2014.
4 x 5 (20) minute exposures. 480/80mm refractor. Ioptron ZEQ25GT mount.
Canon 60Da DSLR with Orion SSAG autoguider/PHD software. Processed in Pixinsight and Photoshop.
In a wide field view, a chain of stars called the “charm bracelet can be seen towards top right”
Twilight last night was fantastically clear and the forecast was good so I set up my 80mm refractor. Took me quite a while since I hadn’t set up my deep sky kit since May.Was a bit slow to polar align and took quite a while to get Autoguider set up.
So, it was with some dismay I saw the clouds come in. I got one 2 minute sub of the open cluster M52 in Cassiopeia and beside it, the beautiful, fragile bubble nebula, Caldwell 11.
This is a bubble of space within a cloud of hydrogen gas. The bubble has been blown by the intense stellar wind coming off a Wolf-Rayet star in the centre. A Wolf-Rayet is a massive star that has blown off its envelope and consists just of a remnant naked stellar core.
WRs are so massive that they burn their nuclear fuel quickly to support their weight and have a short stellar lifespan. They end their lives as Type 1b or 1c Supernovae. They may also be responsible for some gamma ray bursts as there is no envelope to shield the radiation associated with a core collapse supernova.
A direct hit from a gamma ray burst would be, um, very bad for Earth!
The surrounding shell of hydrogen gas around this star is excited by the intense radiation of the stellar wind and glows bright red (hydrogen alpha band, 656nm).
I had planned to take about an hour of 5 min exposures, this is just 2 minutes with no dark or flat frames 😦
Look for the edge of the bubble in the red area near top right.
So cloudy at night. No new imaging. I have reprocessed some shots of M44, the Beehive cluster using some techniques I have picked up recently for Pixinsight.
I have tried to enhance the star colours here but keep them natural as well.
Method 1: contrast enhance linear data for chrominance before stretching.
Method 2: After stretching, use colour enhancement tool with masking at specific points only in the spectrum.
Integration of 4 x 5 minute subs (20 mins total).
480/80mm f6 refractor.1.0 x field flattener. Ioptron ZEQ25GT mount. Guided with Orion SSAG/PHD.Canon 60Da @ 800ISO with clip-in CLS filter. Acquired with BackyardEOS and post-processed in PixInsight 1.8 and Photoshop CS 3.