Again taking the opportunity of a half-hour imaging session, here is M46 in Puppis from the window-sill. Since it is a wide field view, the included planetary nebula, NGC 2438, (a line-of-sight effect, it isn’t in the cluster) appears pretty small, but after a bit of processing you can see it just above centre and slightly to the left. For those of you trying to see it visually, here is a quote from Stephen James O’Meara’s splendid book “The Messier Objects”:
“There is yet another illusion with M46. It appears to contain a tiny planetary nebula. NGC 2438 – – – But the cluster and nebula are not physically associated because the cluster is 5.300 light years distant, whereas the nebula is 6,250 light years away. Positioned just a few arc minutes north of the cluster’s centre, this 11th magnitude planetary measures only about 1’ in diameter. I suspected it at 23X but 72X shows it clearly as a ghostly mote among the multitude”
(I see from my notes that I observed it visually and sketched it at 01:10 UT on 23/12/2001 with my 8″ SCT at X266)
Since there was no moon, I had another go at M48, showing a few more stars than the last one I posted.
For completeness with the Messiers in that region I have also included the recent wide-field image of M47
Managed a 10-minute observing session from the window-sill before the clouds rolled in. M47 is quite large so this time, in order to get a good context, I used a focal reducer. Using a reducer on an f/5 refractor is not optically very good – and it was rather hazy, so the image is not brilliant. You can compare it with the one without the reducer at http://roslistonastronomy.uk/m46-and-m47
Having posted an image of M46 and M47 recently, the other Messier object nearby that I hadn’t yet imaged was M48. I hadn’t managed to locate this object from the window-sill, probably due to its extended size. So, tonight, I installed the focal reducer on the ST80 and went on an M48 hunt. It is full moon (another “Blue Moon”), so it was hardly ideal for DSO hunting!
Still, this time I found it. So here it is after a bit of processing with GIMP.
Here is the view from the window at 5 o’clock this morning. Lots of stuff going on!
This is with the PD camera and 5-100 zoom lens set to 5mm.
Couldn’t sleep again last night. Looked out of the window just before dawn, and there was Scorpius, low down. Just had chance to image Globular cluster M4 near Antares (Dec -26 deg 31 min) before it got light.
After finding out the other day that my ZWO 174 camera doesn’t seem to work anymore, I decided to hang my Canon EOD 450D onto the back of my 8″ Celestron SCT to grab some snaps of Orion while the weather was good (yes, that day really did happen!!)
I was quite pleased with this one although I can’t remember how to get a resizable image onto the blog
My camera’s gone back to 365 Astronomy and they are sending it back to ZWO for replacement (I hope)
I’ve been reading a lot recently about camera noise and recommended ISO settings for each particular camera for astronomy. The camera I’ve been using was said to perform best at ISO 1600 which I think in astronomy terms is actually quite high for a Dslr. So I decided to test this out on the 8th Feb and managed 74x1min exposures at ISO 1600. I was very pleased with the low noise, although the light pollution south of me (Tamworth, Birmingham) was very strong since the horse head is relatively low on the horizon. I’m pleased with the result, although I think with a bit more processing experience I could possibly improve the image??? I was trying out Pixinsight for a second time so I hope to improve over the coming months/years. Canon 6d+Idas d1+Takahashi fsq.
There are a couple of very interesting open clusters in Puppis, not far from Sirius, for different reasons. I found that I had not imaged M47 before, probably because I thought it was a relatively uninteresting plain cluster. Not so! Here is an image of it from the window-sill from yesterday:
I thought at first that the star colours were chromatic aberration, but, in fact they are there in images on the www.. (See https://en.wikipedia.org/wiki/Messier_47). Very colourful!
M46 includes a planetary nebula (NGC2438) in the same field that is very unusual. I didn’t manage to see this one yesterday, but here is an image from 3 years ago,
I’ve been working a couple of hours away from home a lot recently and have become accustomed to driving home in what look like great conditions for a bit of star gazing only to arrive to clouds, rain etc…
The BBC weather page definitely wasn’t optimistic, but after dinner the skies were clear (if not especially transparent) and so I decided go for it. I thought in for a penny and set up the photography rig. Target number 1 was to try and get some images of M51, but on setting up I found that it was hiding behind a tree (all 160 billion solar masses of it!) so I looked for something a bit higher in the sky and decided to go for the Double Cluster:
The images is built from 10x 5min guided subs. I left the camera clicking away whilst I put the kids to bed, and by the time I was back M51 had come out from its hiding place and I attempted the same exposure time. Unfortunately, with the temperature showing -3 in the back garden my camera batteries gave up quicker than usual and I only got 8 before it gave up the ghost. Enough for the results below, however:
Whilst the camera was working on M51 I got the Dob out for some visual observing. I spent a good few minutes on M42 (does anyone else do this every time they observe? I can’t get enough of this target) and then moved up to Alnitak where the sky was good enough for a hint of nebulosity where the flame nebula is. It then took me a while to find the Crab but I got it eventually before moving onto Andromeda and M110. I decided to go for some new (to me) targets and spent some time looking for M101. I definitely saw something in about the right place but not 100% sure so maybe something to have another go at. I decided to go up towards the zenith and see if I could find Kemble’s cascade, but really struggled to see the stars nearby and couldn’t locate it. It was about then that the camera failed so I got the spare battery out and decided to point the camera at Kemble’s Cascade instead. The first sub wasn’t quite aligned correctly (see below) and when I tried to re-align the mount my tablet decided it had had enough of the cold as well (touchscreens don’t work well with frost on apparently) which left me unable to control the mount. I was getting properly cold by now, but at least I’d had a bit of an astro-fix….