Caldwell 49 & 50 in Monoceros
|Magnitude: +5.50||Exposure: 28.7 min.|
|Apparent size of object: 80 x 60 arc min.||Sub-frames: 191s x 9.|
|Diameter: 128 light years.||FOV: 1.57° x 1.06° (up is 4.96 degrees E of N).|
|Distance: 5,500 light years.||Image date: 2021-03-08.|
It seems to have been overcast for most of the summer. I’ve managed to set up the telescope just nine out of eighty-two evenings so far in 2021, including one where thick clouds materialised the moment I was ready and set to start imaging. My last attempt on 8th March was a partial wipe-out, with clouds present throughout. It resulted in the above under-exposed image of the Rosette Nebula.
I shouldn’t complain. We’ve had diabolical weather here over the last week with torrential non-stop rain, causing our main water catchment at Warragamba Dam (capacity 2,031 GL) to overflow, exacerbating already severe floodwaters in Western and North Western areas of Sydney. No lives lost but many homes and businesses destroyed.
The Rosette image was constructed from nine usable sub-frames, out of thirty-five 191 second exposures which were taken. The other 26 were discarded because of poor visibility. So there is not much detail and I’ll need to have another go at this target next year.
It possesses two Caldwell numbers. C49 is the Nebula and C50 is the star cluster. It also contains no less than five NGC designations, which is all rather confusing to a mere amateur astronomer for whom this is effectively one complex but beautiful object to admire.
The weather forecast is giving me hope of some clear skies coming up, although the bright Full Moon is coming. Hopefully I might get a few images, because after that I will not be using my telescope for a few weeks.
Thanks for following my astro-imaging blogs.
Where is it?
| Location of Rosette Nebula in Monoceros|
| Location of Monoceros in celestial sphere|
| nova.astrometry.net |
(If the Astrometry images do not appear it is because the Astrometry website is sometimes off line).
|SkyWatcher Esprit 120 mm apochromatic 3-element refractor; 840 mm f/l @ f/7.|
|Field flattener; ZWO Duo-band Hα (656nm) and [OIII] (500nm) filter.|
|SkyWatcher EQ6-R Pro mount; ZWO ASI120 guide camera.|
|Imaging camera: ZWO ASI 071 MC Pro (CMOS 28.4mm 16 Mpx).|
|Software: Telescope control: Cartes du Ciel, EQMOD, PHD2, Imaging: SharpCap, Gimp.|
|Observatory location: 34° South.|
Images © Roger Powell
I’m a founder member of Macarthur Astronomical Society