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While clouded in and waiting for knee surgery, I started playing with data from the Liverpool Telescope (http://telescope.livjm.ac.uk/). I downloaded all the NSO data on NGC 2841, a very nice flocculent galaxy in Ursa Major, and started processing in PixInsight. While I couldn't get anywhere with the colour of this galaxy, the luminance created from the combined filters revealed structures that I've never seen before in an image of this galaxy.
I combined a colour image of NGC2841 with an inverted superstretch of the combined SDSS-r, Bessell-V, and Bessell-B filters.
Red: 35 frames SDSS-r' Green: 16 frames Bessell-V Blue: 20 frames Bessell-B L image:
integration of all 71 frames, approximately 100 minutes total exposure time. Field size: roughly 10 x 10 arcminutes.
The arrow points at a weak loop, and the circle shows a slight density increase in the weak structure.
A few years ago (already? time flies) @gorann and I hoovered the Liverpool Telescope archives and processed most of the DS data that is in there. https://telescope.livjm.ac.uk/Gallery/
Having not much to do yesterday, I returned for scraps. I found three image files on ngc 891, one red image, one green and one blue image. Each has an exposure time of 90 seconds. I combined the three images into one synthetic L image and processed the data as LRGB. So here it is, 4.5 mintues of professional data
(click on the image for a full size view)
Clearly it pays off to have large pixels and a large mirror on a high mountain top. The telescope is an f/10 RC design with a 2 m mirror and a 4K x 4K pixel camera. Pixelsize is 15 um, but all images are binned 2x2, giving an effective pixelsize of 30 um in a 2 000 x 2 000 array.
The master images had a lot of cosmic rays and hot pixels, so in creating the L master I had to use pixel rejection, which I'd not do normally. I removed much of the cosmic rays and bad pixels in the rgb combined image, before stretching. Here's what the original rgb data looked like.
I didn't realise there was data on this in the School's Observatory archive until I posted a question on the forum. It turns out that you have to have a teacher or student account as the data is in the GCSE Astronomy section.
When I looked I found a lot of images, this is just 120 seconds of R, G, And B. I had to do a gradient removal and a DDP followed by a couple of histogram stretches, ending with a lw-pass filter to get rid of the noise.
The rest of the images in the archive are just 60 and 90 sec which might be OK for preserving the cores.
There's more structure in the image, including the tidal tail but it's very noisy.
As many of you probably already know, Göran Nilsson (@gorann) and I have been processing images from the Liverpool Telescope archives this spring/summer.
After we had hoovered most of the archives, Göran contacted the LT management about our effort. As a result, we were offered to publish our images in their gallery. Now they even presented our work as a news item on the LT website.
Just wanted to share this time lapse of the Liverpool Telescope at work.
Note the large number of movements the scope makes during one night. Every time you see it tracking the night sky, is one imaging session. The data captured during such sessions, is representative of what @gorann and I have been working on for the past time.
Also note that the 'obsy' is completely remote controlled. You can see the various instruments being changed in this video.