Search the Community

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. RGB image: 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. http://telescope.livjm.ac.uk/ http://telescope.livjm.ac.uk/News/#newpics

As @wimvb just said, we are going through the Liverpool Telescope database - a largely unused treasure chest of deep sky data. What else could Swedes do when it is light enough to read a paper outdoors at midnight? Taken together we have done close to 50 images up to now. When I processed this image I had no idea what it was. I found the subs in the data base with the cryptic name "bd65_1637". Only after uploading it on Astrobin, plate solving told me it was NGC 7129. NGC 7129 is a reflection nebula located 3,300 light years away in the constellation Cepheus. A young open cluster is responsible for illuminating the surrounding nebula. A recent survey indicates the cluster contains more than 130 stars less than 1 million years old [all according to Wikipedia] Filters and Exposures used: sdss- r 15 x 90 s Ha 9 x 120 s (stacked 40:60 with sdss-r for red channel) Bessell B 14 x 90 s (blue channel) Bessell V 13 x 90 s (green channel) The scope is a 2 m RC on La Palma

@gorann and I are keeping ourselves busy ploughing through the Liverpool Telescope archives. Every now and then we find some hidden gems in this treasure chest. Here's one that was somewhat of a challenge. NGC 5383 is a barred spiral galaxy in the constellation Canes Venatici. The central part of the galaxy is some 3 arcminutes in diameter. But the interesting features are outside of this. The spiral arms extend well beyond double this diameter. This is rarely revealed in images. Enjoy.

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) Cheers

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.

Following a discussion with Göran, I had a go myself at this galaxy. Since in quite a few images, this galaxy looks rather thick, I wrote that it reminded me of a tractor tire. So, here's my attempt at making this galaxy look less fat. The data is from the Liverpool telescope, a mix of 90 and 120 seconds exposures Red: 19 subs Green: 7 subs Blue: 9 subs Processed in PixInsight As usual, I don't push the saturation and contrast as hard as Göran, but it's basically the same data.

NGC 4216 is a spiral galaxy belonging to the virgo cluster. Its distance is about 55 Mly. Apparent size: about 8 x 2 arcminutes. The galaxy to the left is one of its satellite galaxies (VCC 65 ?). This galaxy shows a very weak tidal disruption due to its interaction with the larger galaxy. (Barely visible in this image.) Data from the Liverpool Telescope, processed in PixInsight

It seems that there are as many variations of this little object as there are astrophotographers tackling it. Had a discussion with Göran in his M76 thread about the colours of this nebula. This is from Ha, R, V and B data from the Liverpool telescope. There is plenty of data, so I only selected one single image exposure time per channel (but approximately 30 - 40 subs per channel). The object has a very bright core and very faint detail further away. HDRwavelet transform was used to tame the dynamic range. In retrospect, I have overdone the deringing during deconvolution, and paid for that with rather soft stars. (The link leads to an album with this image in various sizes)

On the 24th of January 2017, some user of the Liverpool Telescope decided to spend a few frames on Thor's Helmet. This is the only data on this object in the LT database and it consists of seven 120 s exposures, 3 with a Ha filter and two exposures of each of Bessell V (green) and Bessell B (blue). That is not much data but also not much work to stack, so I had a go at it. So this is a 14 min HaGB image. Thus, I put the Ha data in the red channel (since there were no red filter data), which probably explains the slightly unusual colours. All done in PS CS5. This is of course a rather noisy image (pixel peepers should stay away) compared to the Little Dumbbell that I recently posted with 3.6 h of LT data. Still, I am slightly amazed what a big scope can collect in 14 minutes. The scope is a 2 m RC f/10 (so 20 m focal length!) equipped with a 6 x 6 cm (15 µm pixels) 18 Mpix CCD camera (normally run at 2x2 bin) of the brand e2v, which I think is chilled to -100°C.

An HaRGB image I processed of this little cutie tonight from data from the Liverpool Telescope. The following filters and subs were used (90s is an approximate mean of 60-120s subs): Bessell B 33 x 90s Bessell V 28 x 90s rdss-r 42 x 90s Ha 18 x 120s So totally about 3.6 hours of data from this 2 m RC telescope, which is more data than I usually am able to gather from their data base - must be one of their favorites Stacked in Nebulosity 4 and processed in PS CS5 All comments most welcome! (but you may not get an immediate response since I think I am off to bed now).

NGC 6951 is a barred spiral galaxy in the constellation Cepheus, at a distance of about 65 Mly. When the light that was captured here left the galaxy, dinosaurs still roamed the earth. The galaxy has a diameter of about 75 000 ly, or 3.5 x 2.6 arcminutes. The galaxy is surrounded by galactic cirrus, or ifn. The image was taken with the Liverpool Telescope, La Palma, Canary islands (f/10, 2 m mirror, 0.3 "/pixel resolution) Red: 38 x 60 seconds Green: 41 x 60 seconds Blue: 152 x 60 seconds Total integration time: 231 minutes. This time, there was a vast amount of data, especially in blue. I let SubframeSelector do the work and kept only frames with smallest FWHM and eccentricity. (The most common problems with subs from the LT is either poor focusing or poor trailing. I wonder if they use a Bahtinov mask.) Processed in PixInsight

Hubble's variable nebula (NGC 2261, Caldwell 46) is a reflection nebula in Monoceros. The variability is caused by the star which illuminates this nebula. Theory suggests that this nebula was created by the central star expelling matter which interacted with the interstellar dust surrounding it. Image details: Data from the Liverpool telescope (FL = 20 m, f/10, 0.3 "/pixel) 9 x 90 s Bessel-B (blue) 8 x 90 s Bessel-V (green) 13 x 90 s sdss-r (red) 14 x 120 s Ha (click on the image to see the full size version)

NGC 2207 and IC 2164 are very active, colliding galaxies in the constellation Canis Major. According to Wikipedia, they are at a distance of 81 +/- 39 Mly, while the Chandra observatory will have them at 130 Mly, so take your pick. The galaxies have had 3 supernovae in the past 20 years. The pair covers about 4.3' x 2.8' of the night sky, and needs a long FL. (The imaging telescope has a fl of 20 m.) For me, this target is situated well below the horizon; data is from the Liverpool telescope in La Palma, Canary Islands This is a HaRGB image, with 4 - 6 subs per channel. All subs were at most 2 minutes exposures, which gives a total time on target well below 1 hour. The challenges in this image were sensor defects (?), and the Ha combination. Most of the images taken with the LT were to study supernovae, so framing varied, and I had to crop the image. Several subs had bad lines which I removed by using CanonBandingReduction on a small section of the image. The small galaxy to the right of IC 2163 was not identified by either PixInsight or Astrometry.net. Another galaxy off to the lower left, had to be cropped due to stacking edges. (In the annotated image, RA goes from bottom to top, and DEC goes from right to left.) This image is very much a work in progress, as I believe it has much more to offer than shown here.

In Sweden there are no darks nights until September so like Wim up here I have to satisfy my processing addiction with free data like those from the Liverpool Telescope on La Palma, Canary Islands. Here is the Antennae Galaxy (NGC 4038+4039). It is quite a mix of subs but essentially it is a LHaRGB image, stacked in Nebulosity 4 and processed in PS CS5. Subs used: sdss-r 3 x 120s + 2 x 30s, Ha 1 x 120s (added to sdss-r); Bessell V 2 x 120s + 1 x 30s; Bessell B 3 x 120s + 1 x 90s + 2 x 30s; Clear (luminosity) 13 x 120s + 6 x 90s + 2 x 30s. So totally: 58 minutes. Not much but 2 meters of aperture helps. The blue shine down to the left is not a gradient. It comes from a big star. These are actually two closely interacting galaxies and are sometimes also called The Antennae Galaxies. Apparently a lot of violent forces are at play here. It's a pity that the antennae are cut of by the rather small FOW of this scope. Comments and suggestions most welcome.

NGC 7479 is a barred spiral galaxy in the constellation of Pegasus. The data for this image is from the 2 m f/10 Liverpool Telescope in La Palma, Canary Islands 20 x 90 seconds RGB (sdss-r, Bessel-V, Bessel-B), total integration time: 30 minutes / channel Processed in PixInsight. The data was extremely strong in red, and weak in blue. I started with integrating all colour information I could find in the archive, but the blue showed some anomalies. I kept only the 90 s data files. This is basically the full frame from the camera (2000 x 2000 px, 15 micrometer pixelsize).