Recently Browsing 0 members
No registered users viewing this page.
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.
This image may compete for being one of the worst framings ever.
It is an RGB image that I processed from free data from the Liverpool Telescope, a 2 m RC reflector on La Palma. This time with quite a lot of data, so not much noise and a lot of detail. The "only" problem is that the astronomers requesting the subs must only have cared about NGC 3187 and the beautiful NGC 3190 just happened to be partly included.
Found this nice info about these galaxes on the Canary Islands Astronomical Institute www.iac.es:
Discovered by Sir William Herschel in 1784, NGC 3190 and NGC 3187 are two spiral galaxies seen nearly edge-on. The spiral arms of NGC 3190 are tightly wrapped around its nucleus, and those of NGC 3187 are S-shaped. Both galaxies are located in the constellation Leo and are members of the Hickson 44 galaxy group, located about 70 million light years from Earth. The galaxies in this group are very close to each other so that gravitational interactions are common, resulting in a high degree of shape distortion and a high rate of star formation in many cases. This gravitational dance will eventually end up in many galaxy mergers.
Filters and exposures used (from 2015 01 21 - 2016 04 26).
sdss-r 40 x 90 s (red channel)
Bessell V 23 x 90 s (green channel)
Bessell B + sdss-g 53 x 90 s (blue channel)