Recent pictures from COAA
From time to time we participate in asteroid occultation observations by the European Astroid Occultation Network (EAON). Timing the disappearance of a star as an asteroid passes in front of it, allows very precise determination of the orbit of the asteroid and, potentially, of its physical dimensions.
The clip (left) shows asteroid Aegle-96 occulting a magnitude 10.3 star in Aquarius. It was recorded using a Mintron video camera on the 20cm Newtonian.
The small star-like points are hot pixels in the Mintron camera. The target start is in the centre of the animation. The clip is speeded up; in real time, the occultation lasted for 10 seconds. According to the best estimate of the diameter of the asteroid, the shadow must have passed almost directly over COAA to produce such a long occultation. The asteroid itself, some 2 magnitudes fainter than the star, is dimly visible during the occultation. For comparison, a field star visible to the southeast (down left) of the target has magnitude 12.8 which is close to the published magnitude of Aegle-96 (12.6).
Jan Wrightson, a regular at COAA, used our smallest scope (8" - 20cm f/4.4 Newtonian), to capture this image of M101 in Ursa Major (left). A surprising number of visitors tell us that, until they came to COAA, they had never seen this large, but faint, face-on spiral galaxy for themselves. Using her Canon DSLR, and multiple exposures, Jan has managed to reveal colourful details in the spiral arms even with a relatively modest telescope.
Using a somewhat larger telescope (12" - 30cm f/5 Newtonian), Jan made this study of the galaxy pair M65 and M66 in Leo (right). M66, on the left, is the brighter of the two and it has a conspicuous bar in the centre. M65, on the right, is also a barred spiral although the angle makes it more difficult to discern from our viewing angle. Despite being so close together as seen from Earth, and despite being both barred spiral galaxies, the two are apparently unrelated being respectively 32 and 56 million light-years away.
Regular visitor to COAA, Nick Norman took this fine shot (left) of M51, the Whirlpool Galaxy in Canes Venatici, using his DSLR camera on the COAA 0.5m autoguiding for a total of almost half an hour of total exposure time. Note the reddish colour of the older stars in the companion galaxy on the left of the image and the blue cast of the young hot stars in the larger galaxy on the right. The original image shows a great deal of detail in the spiral arms including several HII regions as well as the plumes of stars peeling off to the left (North) the companion galaxy which are strongly suggestive of gravitational interaction between the two galaxies.
On this occasion, Nick's visit coincided with significant moonlight but, astonishingly, he managed to obtain this image (right) of M108 in Ursa Major only a couple of days before Full Moon. As with the M51 image this was captured with the COAA 0.5m using autoguiding. There is a distinct colour contrast between the outer regions and the inner regions of this spiral galaxy.
This detailed study of M27 (left), The Dumbbell Nebula was taken by Frank Johns, a member of a party of vising astroguests from Brannel Astronomy in Cornwall. This picture is the combination of eleven, two-minute exposures with his digital SLR camera on the COAA 0.5m Newtonian. This nebula surrounds a tiny white dwarf star - seen as blue dot in the centre of this image - which is all that remains of a Sun-like star that ran out of fuel thousands of years ago.
Frank also captured this fine view (right) of the Summer Triangle and the Milky Way that passes overhead COAA during the summer months. This picture is a combination of eight, three-minute exposures taken with Frank's digital SLR camera on a driven mount.
This crater (right), named for Edwin Hubble, on the extreme limb of the Moon can only be seen as certain points in the Moon's libration (apparently rocking from side to side as our viewpoint changes). Images like this one, captured with a web cam on the COAA 0.5m telescope, give the sensation of being really close to our arid and airless co-planet.
The Orion Nebula, M42, is a particular favourite in the early part of the year. This image (left) was taken with the COAA 0.5m Newtonian and the Canon Digital SLR camera. The dynamic range of this object is extraordinary with the bright Trapezium star group in the centre burnt out in this exposure but with the fainter "wings" of nebulosity extending far out of this picture. M42 is part of a very large region of hydrogen that extends almost the full height of the Orion constellation.
The Summer Triangle is amost overhead at COAA during the summer months and contains a host of beautiful deep sky objects in Milky Way. Gordon Mackenzie used the COAA 0.5m Newtonian and the Canon 300D Digital SLR camera to capture this picture (right) of NGC6888 in Cygnus. Known as The Crescent Nebula this cloud of glowing hydrogen is part of a large group of nebulae in the vicinty of Gamma Cygni.
Springtime at COAA is a very rich period for galaxies with Leo, Ursa Major and especially Virgo and Coma Berenices will placed for observing. Nick Norman, on one of his frequent trips to COAA, captured this study (left) of the spiral galaxy M61 in Virgo using the COAA 0.5m Newtonian. The spiral arms in this galaxy have a strangely rectilinear form.
Regular astroguest Greg Beeke brought his delightful family for another visit to COAA in July 2006. He also brought along his impresssive Yankee Robotics Trifid camera and captured this superb image (right) of M16, The Lagoon Nebula in Sagittarius, combining white light exposures with exposures through a Hydrogen Alpha filter to produce this coloured image. This object includes the three fingers of gas made famous by the Hubble Space Telescope image dubbed The Pillars of Creation.
On the morning of 2005 October 03 we were able to witness a partial eclipse from COAA.
The eclipse was annular in the north of Portugal; down here in the Algarve,
we were treated to a partial eclipse with more than 83% of the Sun's disk covered by the Moon.
As usual on these occasions, we
held an open house and around 45 people took part in the event (left, Nick Norman).
The animation (right) is a very small digest of a complete record of the event captured by Nick Norman.
Nick was the winner of last year's photography competition and his stay at COAA for this event was his competition prize.
The event was made even more interesting because astroguest Andrew Dumbleton had brought a Coronado solar telescope with him
and the Sun obliged by displaying a superb prominence which visitors were able to watch developing.
Danish AstroGuest Ole Nielsen captured this image (left) of the Trifid Nebula (M20) from COAA using his Takahashi reflector and his SVM imager. Ole used a set of Astronomics colour separation filters to create the LRGB components from which he blended this beautiful picture. The red portion of the nebula is shining by fluorescence caused by radiation from the hot young double star at its centre. To the north of the emission region is the blue reflection nebula which makes this object such a strikingly colourful composition. The original image covers a much larger area of sky but has been cropped to fit onto this page.
On his second visit to COAA, celebrated astrophotographer Peter Vasey captured this impressive study (right) of the star formation region known as the Lagoon Nebula (M8). Peter used his home-built Artemis CCD imager with a Hydrogen Alpha filter to reveal the full extent of this fascinating nebula. Most images of M8 concentrate on the brighter central region but Peter's image show just how large and complex this object really is. The popular name of the object arises from the dark lane that sweeps diagonally through the nebula to the southeast of the brightest reagion. The image has been substantially reduced in size to fit this page.
For comparison, this image of M8 (left) was made using the COAA digital SLR camera on the 0.5m Newtonian telescope. The less sensitive colour imager loses the faint detail but gains from the vibrant colour of the subject. M8 is a star-birth region in Sagittarius visible to the naked eye from southern Europe as a faint smudge in the direction of the centre of the Milky Way.
Peter Vasey also brought along a SolarScope on his visit to COAA. Happily the Sun obliged with some interesting features as this example (right) shows. At the original scale, the image shows a wealth of detail in the granulation on the Solar surface. This is essentially a monochrome image as it was photographed through the narrow band Hydrogen Alpha filter in the SolarScope. The red ring around the Sun is an artefact of the processing that was performed to bring out both the promenances on the limb and the granulation of the surface.
The Eagle Nebula (M16, left) in Serpens is the home of the Pillars of Creation that were made famous by the superb Hubble Space Telescope image. In this picture, taken with the digital SLR camera on the COAA 0.5m Newtonian, the three dark fingers can be seen in the centre of the frame. Visually they are difficult to discern because of the bright stars embedded in the nebula. On the image, the features stand out plainly. Opinions differ about which attributes of the nebula afford the name 'Eagle'. Some people look at the overall outline of the nebula while others recognise the largest 'pillar' as being the forehead and beak of an eagle.
All eyes were on comet Temple/9P (right) on the Fourth of July because it was the target of the Deep Impact mission. Although it was getting rather too far south to be seen from northern Europe, we had a good view of the comet both before and after the imact occurred. Comparing images it was clear that there had been a slight brightening of the comet as a result of the impact. When this image was taken, on the evening of July 4, the comet (diffuse object on the left of the CCD image) was passing east of the small galaxy PCG48179 which can be seen on the right edge of the picture. The galaxy is 55 million light years from Earth and the comet is just 7 light minutes away. A pair of 'faint fuzzy objects' with rather different characteristics.
On another of his visits, Nick Norman captured this fine image of the North American Nebula (NGC7000, left) in Cygnus using a regular camera lens on his Canon 300D. Nick has modified the camera by replacing the IR filter to enhance the sensitivity of the camera to Hydrogen Alpha emissions. This is a very much reduced version of the original magnificient image.
M82 (right) is an irregular galaxy in Ursa Major. This image, also taken with the digital SLR on the COAA 0.5m Newtonian, shows the pronouced pink colouration of the central region of this complex structure. M82 is one of the most colourful of the bright galaxies that are in our vicinity.
The Sombreiro Galaxy (M104, left) is always popular for imaging. Low down in the constellation Virgo it is small but bright and the edge-on presentation shows up the dusk lanes that surround the disk.
M83 (right) in Hydra is too far south to be seen well from northern Europe. From COAA it stands well above the southern horizon and presents an impressive face-on view displaying the central bar. The new digital SLR brings out the blue, star-formation regions in the outer arms when placed at the focus of the COAA 0.5m Newtonian.
The Whirlpool Galaxy (M51, left) in Canes Venatici is a popular object. It is one of the few galaxies whose spiral structure can seen identified visually in the COAA 0.5m Newtonian. The digital SLR image reveals the bluish colour in the star formation regions in spiral arms of the main galaxy and also the reddish tinge of the companion galaxy. 
Early in July, a supernova was discovered in M51. The image at right was taken with the COAA SX CCD camera and clearly shows the supernova in the first spiral arm south of the nucleus of the main galaxy. Comparing the colour image of the same galaxy on the left, there is no star-like feature visible at that point in the spiral arm.
The Cat's eye Nebula (NGC6543, left) in Draco is bright enough to image with a modified web cam. The immediate colour and high resolution of the camera brings out some of the detail in this tiny planetary nebula. The white dwarf star that gave rise to the gas is visible as the blue central feature surrounded by the glow of the ionised gas which the star shed late in its lifetime.
Inspired by the results that AstroGuests have been obtaining with digital SLR cameras, we acquired a Canon 300D camera for the exclusive use of visitors to COAA. This picture of the great globular cluster in Hercules, M13 (right), shows the capabilities of this camera for astronomical imaging. The ability to capture a high resolution colour image in a relatively short exposure has radically increased the productivity of time at the telescope.
If you can see stereo using the 'splayed eyes' method then you should enjoy this pair of images of Jupiter (right) taken a short time apart. The difference in perspective resulting from the rapid rotation of this enormous planet gives us the opportunity to appreciate the third dimension using the stereo view. The orange patch just below the equator is the celebrated Red Spot. You need to look 'through' the image, as if looking at a distant object to grasp the stereo view. Some people find it easier to do this if they are wearing reading glasses and look at the pair close up.
Regular AstroGuest Nick Norman used his first-off-the-line Artemis CCD imager to capture several challenging objects during his first visit of the year to COAA. This image (left) of the large face-on spiral galaxy M101 in Ursa Major, illustrates the power of the instrument. M101 is large and complex but its low surface brightness makes it a challenging object. Using the COAA 0.2m Newtonian Nick was able to encompass the whole of the galaxy while bringing out the interesting structure in its spiral arms.
As April progressed, Jupiter became better placed for evening observing.
AstroGuest Danny Radnzic used a web cam and the COAA 0.5m Newtonian to capture this image (right) of Jupiter.
Danny chose an evening when Io was transiting the disk of Jupiter closely followed by its shadow.
In this image, Io has just completed its transit but its shadow is still just visible as a slight nick in the circumference of the planet.
During March 2005, with Saturn almost overhead in the early evening, it was impossible to resist imaging it with the 0.5m Newtonian.
Although the atmospheric stability was far from ideal, stopping the scope down to f/15 and processing 450 frames with Registax produced this result (right).
Features to note include the Cassini division, the shadow of the planet on the rings and the equatorial band.
A longer exposure showed four of the moons of Saturn but substantially over-exposed the planet itself. The image on the left is a collage of short and long exposures.
On the evening of 2005 March 4, the ESA spacecraft Rosetta performed a slingshot manoeuver around the Earth. Although it was launched a year ago, it used the Earth to accelerate its orbital velocity to reach its eventual target. We imaged the fast moving spacecraft (left) using the 20cm Newtonian and the WinCTC mount controller to locate the rapidly moving object. The Rosetta spacecraft will be the first to undertake the long-term exploration of a comet at close quarters. It comprises a large orbiter, which is designed to operate for a decade at large distances from the Sun, and a small lander. It will enter orbit around Comet 67P/Churyumov-Gerasimenko in 2014, and will release a small lander onto the icy nucleus. The orbiter will then spend the next two years orbiting the comet as it heads towards the Sun. On the way to Comet Churyumov-Gerasimenko, Rosetta will receive gravity assists from Mars as well as this encounter with Earth, and will fly past main belt asteroids en route to the comet.
Although the weather in the second half of October was more changeable than usual,
the clouds relented in the early hours of October 28 allowing us to enjoy the lunar eclipse (right).
The eclipsed Moon displayed a deep russet colour illuminated only by the twilight glow creeping
around the circumference of the eclipsing Earth. During the eclipse, we took the opportunity,
provided by the attenuated moonlight, to observe a few deep-sky objects and to enjoy a surprisingly
large number of meteors (mostly Taurids and Orionids).
The face-on spiral galaxy NGC6946 has hosted a surprisingly large number of supernovae over the years.
The latest is 2004et discovered at the end of September 2004 by Stefano Moretti.
Currently between magnitude 12 and 13, the supernova is readily visible in the larger scopes at COAA.
This image (left) was captured by AstroGuest Nick Norman using the smallest scope that we have at COAA (20 cm Newtonian)
together with his highly modified web-cam. Coincidentally, the image was captured on almost exactly the four-hundredth anniversary
of the discovery of Kepler's star - the last supernove to be observed in our own galaxy.
A stack of 10 exposures of 20 seconds each, yielded this image
with the supernova conspicuous beside the double star on the left side. The image is blinking with a reference
image of the same galaxy (rather more of the galaxy is visible in the reference image). It appears that the supernova
is outside of the periphery of the galaxy but in fact it is within one of the faint outer arms. The magnitude of the supernova has not changed substantially
since its discovery but presumably it will soon be starting to fade.
We have just started experimenting with the new SAC Imaging Mintron video camera. This intriguing camera incorporates on-chip integration but also displays live video while doing so. The SAC product includes a USB video capture device so that using our AstroVideo capture program, it is possible to see live views of deep sky objects. These images from Sagittarius were made by integrating just 10 images captured from the live video stream with the camera set to integrate 128 frames. The images are displayed continuously but update every two seconds in this mode. Accordingly, these pictures took only slightly over 20 seconds to capture. The images of the splendid globular cluster M22 (right) and the Trifid Nebula M20 (left) were made using the COAA 0.2m f4.4 Newtonian. The SAC Mintron camera has a large chip which makes it possible to cover a relative large area of sky. In the case of the image of M20 (left), the image field is large enough to show reflection nebula just above the trisected emission nebula. In fact the image shown here gives only a part of the original field of view. There are two obvious applications for which this camera is especially well matched. The obvious one is star parties and public viewing nights where many people can watch the live image of deep sky objects at the same time. The other application is for image capture on telescopes whose tracking is not perfect. With a refresh rate of only 2 seconds, even a poorly driven mount should produce steady images. With the integration tools of AstroVideo or FitsX, you could combine many such images into a final product even though they may not be exactly aligned with each other because of imperfections in the mount.
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We received an email from the good folks at iss-transit.sourceforge.net telling us
that the International Space Station was going to pass in front of the Sun, as seen from COAA.
This rather rare event occurred on 20 June very close to local noon.
As a result, the Sun was just about as high as it ever gets over mainland Europe.
We recorded an AVI file of the Sun, using our VestPro camera and a 350mm telephoto
lens to obtain an image covering most of the Sun's disk. Looking at the Sun visually
(with appropriate filters!) the space station was seen to flick across the upper left corner of the disk
in a split second and might have been an insect. Examining the AVI file after the event, revealed the
silhouette of the Space Station on four successive frames (recorded at 15 frames per second).
Although the heat of the midday Sun made the image rather unstable, the close up (left) of the first frame
shows the outline of the solar panels and closely matches the simulated view (right) of the station which
was generated for the same instant, viewing from COAA using the ISSsimulator software.
2004 is proving to be a fruitful year for comets. As comet Neat 2001 Q4 is starting
to fade from view in the northwest, the new comet Linear 2003 K4 (left) is brightening in the northeast. The comet will
continue to brighten as it moves south over the next few months. We will benefit from our more
southerly latitude at COAA, as we will continue to enjoy it for a while after it becomes too far
south to be seen from northern Europe.
Although it is more difficult to image deep sky objects when the Moon is approaching full,
the Moon itself makes an interesting subject. This image (right) is of the 13.5 day old Moon.
The image includes a number of striking (!) features including the rayed craters of
Tycho (in the south) and Copernicus (just above the equator). North of the largest
mare (Imbrium) is the crater Plato which has a very dark floor.
The Moon was imaged using the COAA 0.2m Newtonian, a Vesto Pro web cam and
the COAA AstroVideo software. Each captured image covered only a small part of the Moon's
disk and so the images were combined into a full disk image using Jon Grove's excellent
iMerge software. This program creates a montage in a semi-automatic way without
creating artefacts at the boundaries between the contributing images. Although this image
has reduced in size to fit the web format, the original composite image was 8.5 Mb.
On the night of 7 May 2004, comet 2001/Q4 NEAT was a fine object in the southwest after sunset visible to the unaided eye. We captured a long series of exposures using the COAA 0.2m Newtonian and stacked them centring on the comet nucleus to produce this image (right). The trailing of the stars shows how fast the comet was moving. We also make an animation of the movement of the comet but it is too large to post here. A series of radial features can just be discerned in the tail to the left of the nucleus.
On the night of 26 April 2004, the atmosphere was unusually stable. We fitted our modified web cam to the COAA 0.5m telescope and captured this fine image of Jupiter (left). The image was produced in two stages. Using the COAA AstroVideo software, we captured an AVI file consisting of just under 500 image frames. This process took half a minute or so. The AVI file was then processed with Registax to combine the images into one (a process that took very much longer than the capture time) and the resulting image is shown at left. A number of interesting features are revealed by the image most prominently the Red Spot which is just about to disappear around the limb on the right side. More salmon pink now, than red, it is much less obvious visually but shows up well in this picture. A similar picture taken just a few minutes earlier graphically illustrates just how rapidly Jupiter rotates. When the two images were alternated using the COAA FitsX software, the rotation between the two was very obvious.
Towards the end of March 2004, AstroGuest Mike Usher brought his Canon 300D digital SLR camera which he fitted to the COAA 0.5m Newtonian telescope. Unusually, the 300D is able to do indefinitely long exposures and it is much more sensitive than film. Mike was able to capture colour pictures of many deep sky objects including ones shown here. The image on the left is the Owl Nebula M97 in Ursa Major. This is a large but rather dim planetary nebula near to beta Ursae Majoris which is usually quite difficult to image, especially in colour. The central star in the nebula is a white dwarf star and its exceptionally high surface temperature is revealed by its blue-white colour, especially when compared with the other stars in the field. The image on the right is the Whirlpool Galaxy M51 in Canes Venatici. Although galaxies are not generally very colourful, the upper satellite galaxy NGC5195 is clearly roseate in this nice picture especially when compared with the primary spiral galaxy.
The Orion Nebula M42, on the left, is always a firm favourite at this time of the year and the colour capabilities of the 300D made it a natural target. Unlike other deep sky colour imaging techniques, these pictures have not been adjusted for colour balance and are simply as delivered by the camera. This subject is a difficult one for most astronomy CCD cameras because of its large size in the COAA 0.5m telescope. The larger chip size of the 300D makes it possible to use the large telescope on such extended subjects.
AstroGuest Gordon MacKenzie, on one of his regular visits to COAA, captured this fine picture (left) of the Helix Nebula (NGC7293) in Aquarius. With a declination of almost 21 degrees South, this is a difficult object from much further north than the latitude of COAA. To create the picture, Gordon used the monochrome SX CCD camera with a succession of colour filters to generate LRGB images that were combined using the COAA FitsX program to produce the final result shown here. The Helix Nebula is the largest planetary nebula; it surrounds a white dwarf star whose characteristic blue-white colour can be seen in the centre of the nebula. The nebula itself is almost two light years in diameter and is the closest such nebula to the Earth at a distance of about 650 light-years. The green colour of the central area comes mainly from the dominant 500nm O-III line and the red, outer colouration is mainly the familar 656nm H-alpha line. All of the emissions are excited by the intense UV radiation from the white dwarf star.
Mars (right) is now clearly showing a gibbous phase as we draw ahead of it in our orbit around the Sun. This image is at the same scale as the other images lower down this page; notice how the apparent diameter of the planet is shrinking as the distance between us increases. This view once again shows the dark triangular shape of Syrtis Major and the lighter area of Hellas between it and the now very tiny South Polar Cap.
This image of the northwest flank of the 12-day-old Moon (left) shows the bright, rayed crater of Aristarchus and, to its west, Herodotus. The image covers an area of about 320 km from East to West and 240 km from North to South. To the North of the two large craters is the sinuous rille called the Schoter Valley. The rille is between 6 and 10 km wide over most of its length but at its western extremity it is only 500 metres wide. In the upper right corner of the image is a fault line called the Toscanelli Scarp. The large crater on the lower right side of the image is Prinz which is partially filled with lava from the Oceanum Procellarum. The smallest craters in the image, such as the one in the northern rim of Herodotus (Herodotus N), are about 4 km in diameter.
Although we are now moving away from Mars, it is still an object of fascination to visitors at COAA. A humid air mass from the south brought a night of good stability ("seeing") on September 20. Using a simple web cam on the COAA 0.5 m Newtonian telescope produced this fine image (right) of the red planet. We used the COAA AstroVideo software to gather an AVI file containing around 900 separate images of Mars and then processing the AVI file with Registax to create this image. Compare the now shrunken South Polar Cap with the same feature on images further down this page taken earlier in the Martian southern summer. The relatively isolated dark spot close to the centre of the disk is Solus Lacus and the larger dark area to the right of it is Mare Erythraeum. Chryse is the lighter area on the upper right flank. It is clear that we are no longer overhead the midday longitude on Mars as the overall shape of the planet is becoming distinctly gibbous.
Marcus Werner, a student volunteer helper at COAA has a particularly interest in the globular cluster M15 in the constellation Pegasus. This cluster is unusual in that it contains a tiny planetary nebula, known as Pease 1 (or Kuestner 648) which is a cloud of ionised gas surrounding a white dwarf star. Because M15 lies some 40,000 light years from Sun, and because the stars within the cluster are very densely packed, the planetary nebula within it is rather difficult to detect. Marcus used the COAA 0.5 m Newtonian to image the cluster and used an interesting technique to highlight the planetary nebula. By taking a series of CCD images with, and without, a narrow band filter which favours the emission lines that are characteristic of the nebula (Lumicon UHC) , Marcus created this false-colour image (left) in which the blue and green colour components are based on the unfiltered images and the red colour component is based on the filtered images. The luminance contribution was also based on the unfiltered images but having undergone a non-linear transformation to compress the wide dynamic range between the brightest and faintest parts of the cluster into something which could be visualised. The pink dot, which is visible just above and to the left of the nucleus of the cluster, is the planetary nebula Pease 1. In that very little interstellar material (gas, dust, etc) is known inside globular clusters, Pease 1 is a most remarkable, if elusive object.
On the night of 5 September the newly discovered asteroid 2003RB5 flashed past the Earth at the
perilously close distance of 0.029 AU. The orbit of the asteroid is such that the IAU Minor Planet
Center defined it as a potentially hazardous (to the Earth) object.
Because of its proximity, 2003RB5 was moving across the sky at around one arc minute per minute. Being rather faint, this meant that the image was far too spread out to register on an image which was tracking at the sidereal rate. Using the ability of the WinCTC (www.winctc.co.uk) telescope mount to track a solar system object, we made a 120 second exposure of the area with the mount tracking, not at the sidereal rate, but at the specific rate that 2003RB5 was moving. This image (right) clearly shows the tiny object among the trailed star images.
Just a few hours after opposition, we captured this image of Mars using the COAA 0.5m Newtonian and the VestaPro web cam and processed the result in Registax..
The South Polar Cap is visibly shrinking as the southern summer progresses. The familar triangular shape of Syrtis Major dominates the upper part of the image. The Hellas region, just above the South Polar Cap, appears to be partly oscured by a dust storm. The Sinus Meridiani reaches off to the left limb.
As Mars' closest opposition for several millenia approached, AstroGuest Robin Levett captured this image of the Red Planet using the COAA 0.5m Newtonian. Robin used the VestaPro web cam to capture 900 images into an AVI file. The image (right) is the result of processing those images with Registax.
The bright South Polar Cap is the most conspicuous feature at the bottom of the image with the Hellas region to its right on the limb of Mars. The dark sinuous band running from just above the centre to the lower right is the Sinus Meridiani with Noachis Terra below it. The dark region to left of Meridiani, separated by a light band, is the Margaritifer Terra - a heavily cratered area. The dark triangular region in the upper left quadrant is the Acidalia Planitia.
Once again we held a Perseid Meteor Party at COAA on the night of August 12. This time conditions were less propitious. As well as a Full Moon we had to contend with the smoke from a forest fire in the mountains to north of COAA. Even so several of the 69 people, from 8 countries, who were present, were able to spot the brighter meteors that passed overhead. As usual, the meteor visualization software, R_Meteor, was put to good use and we recorded a busy night of meteors detected by radio scattering even though the visual display was muted. This clip shows an 18 minute period around 05:00 UT in which 36 separate meteors can be seen. The diagonal lines are aircraft trails and the continuous centre line is the remote transmitter signal.
This spectacular image of Mars (left) was captured by AstroGuest Gerry Doyle using the COAA 0.5m Newtonian. Gerry used the COAA AstroVideo software with an unmodified ToUcam web camera to capture 900 image frames in an AVI file. To reduce the brightness of the images and to limit the effects of atmospheric turbulence the telescope was stopped down to f/15.
Gerry's AVI file was processed by Dr Steve Wainwright using Registax to align, stack and
process the resulting image. Many features are superbly presented here including the conspicuous South Polar Cap, the bright Hellas region above it, and the triangular Syrtis Major feature above that. The bluish haze around the left limb is the familiar morning mist effect where the sun is just rising over that part of the planet. The region to the right of Hellas is usually dark so the sandy colour in this image implies a local dust storm on the surface of the planet.
AstroGuest Dr Steve Wainwright, founder and patron of the QCUIAG on-line think-tank brought a bewildering array of electronic imagers with him during his month-long stay at COAA. Here is a selection
of the many superb images that he captured during his stay. Note that these images were all taken with low-cost web-cam-based imagers in order to illustrate the potential such equipment has. All of these images were made with a colour camera installed on the COAA 0.2m Newtonian reflector - the smallest telescope at COAA.
On the left is an image of the Lagoon Nebula (M8) which is a star formation region in Sagittarius.
The nebula takes its name from the diagonal dark band that transsects the glowing gas. The cluster to the left consists of newly-formed stars whose high surface temperature generates sufficent UV radiation to cause the gas to flouresce.
On the right is the Trifid Nebula (M20) also in Sagittarius. The name of the nebular (correctly pronounced "try-fid" not "triff-id") refers to the dust lanes that trisect the gas. The name has nothing to do with John Wyndham's famous gardening book which has two f's in the title.
The nebula on the left rejoices in several names. It is known as the Horseshoe Nebula, the Omega Nebula and our own favourite, the Swan Nebula. It is also M17 in Messier's list and sits on the boundary of Sagittarius, Serpens and Scutum. Steve's modified web-cam has not only captured the brighter parts of the nebula but also the fainter 'wake' behind the swan.
The nebula on the right is the Eagle Nebula (M16) in Serpens, made famous by the Hubble Space Telescope image which was dubbed the Pillars of Creation. The three dark fingers within the nebula can be glimpsed in the centre of the glowing gas. The centre finger is the most conspicuous of the three, pointing up and to the right towards the densest part of the star cluster.
The telescopes at COAA are optimised for deep sky observing. However, they can
still be used for objects that are closer to home. This image of a small part of the
seven-day old Moon (left) was made using a VestaPro SC web cam on the COAA 0.5m Newtonian.
The gash in the crater floor, lower left of centre in the extract, is called the 'Straight
Wall'. You can see from the image that is it not quite straight and it is not a wall. It
is an escarpment resulting from a fault in the crater floor which throws a shadow before Full
Moon and shines brightly after Full Moon.
On the morning of 07 May 2003, Mercury crossed the disk of the Sun.
The last transit of Mercury that was visible from Europe occurred on 10 November 1973 and the next
will be on 09 May 2016.
We carried out a live webcast of the transit from the time that it reached an adequate elevation seen from
the Algarve, to the end of the event some three hours later. Images were captured and automatically
uploaded to our website using the script facility in the COAA AstroVideo
software. This final image (right) shows the situation just a few seconds before the end of the transit
at 10:33 UTC when Mercury was about to leave the disk of the Sun. If you have the bandwidth, you can
download a time-lapse movie of the last twenty minutes of the
transit.
Regular Astroguest Nick Norman brought with him two web cams that he had modified
for astronomical imaging.
The image of Jupiter (right) was made with a Colour Quickcam Pro 4000 with the SC1 modification.
Using the COAA 0.5m telescope, Nick captured an AVI file and then processed it with
Cor Berrevoets's Registax program. The moon Europa is visible to the left of Jupiter's disk
and the Great Red Spot is conspicuous on the face of the planet. Nick captured this superb image of M66 (left)
with a web cam that was originally a Vesta Pro but with the SC3.1 modification replacing the
colour CCD chip with a larger and more sensitive monochrome chip. A set of 10 x 20-second exposures,
using the COAA AstroVideo software, were combined using the COAA FitsX software to give this
remarkable result. Both of these pictures approach the quality of images produced by much more expensive
cameras but were taken with relatively low-cost equipment.
On the night of 2003 April 01/02, astroguest George Gilbart-Smith joined the elite ranks of those who have successfully completed a Messier Marathon - observing all 109 objects in the Messier catalogue in a single night. George used a combination of his own field glasses, a portable Alt/Az 15cm Newtonian and a 30cm Dobsonian-mounted Newtonian. The portable instrument was used for the early-setting objects which were low in the west after twilight. George had practiced finding the critical objects over the preceding nights but conditions were only sufficiently good to complete the Marathon on the night of April 01. During parts of the night George was accompanied by other astroguests at COAA. Although the Marathon has been attempted many times at COAA, this was only the third successful attempt. It is generally considered that the Marathon cannot be completed from anywhere much further north than COAA. It requires a cloudless transparent sky on a night close to 31 March and with the New Moon falling close to the same date. George is seen here (right) on the morning of April 02 (smiling broadly) with the instruments that he used.
Astroguest Peter Vasey used the COAA 0.5m Newtonian and his own Starlight Xpress MX716 ccd camera to capture this image (left) of Hoag's object. This unusual ring-type galaxy was recently studied by the Hubble Space Telescope and consists of a central galaxy with a preponderance of red stars surrounded by a ring galaxy with mostly blue stars. Various theories for its origin have been proposed. Most of them involve an early collision between two galaxies. The object is of magnitude 16 and lies approximately 600 million light-years away.
Australian Astroguest Dr Mehryar Nooriafshar used the COAA 0.5m Newtonian to capture a sequence of Jupiter images to produce an animation showing the rotation of the planet. This is one frame (right) from the animation. Jupiter's innermost moon Io can be seen off to the right of the planet. Another moon, Europa is just ending its transit across the face of Jupiter at the rightmost edge of the planet's disk. The shadow of Europa on the Jovian cloud tops is conspicuous as a black dot to the left of centre between the northern and southern equatorial cloud belts. Just down and to the right of Europa's shadow lies the "Red Spot" which is an orange oval indentation in the southern edge of the southern equatorial belt.
Regular Astroguest Gordon MacKenzie created this colour image (right) of the Horsehead Nebula in the constellation of Orion, using a set of CCD images taken through red, green and blue filters. Gordon used the same technique on Messier object M1 (left). The image reveals the complex structure of this dramatic remnant of a supernova that was observed to take place in the constellation Taurus almost 1000 years ago. Both of these images were taken with the most modest equatorial telescope at COAA; the computer-controlled 0.2m f4.4 Newtonian.
Using the same small telescope, but this time using a modified web cam as the imager, we captured this enchanting image (left) of the planetary nebula in Hydra known as the Ghost of Jupiter (NGC3242). The web cam provides an immediate colour image and is ideal for bright objects with fine detail. Seen visually, even with the largest scopes at COAA, it is difficult to see any detail within this planetary although experienced observers generally report the turquoise colour.
A while ago, AstroGuests Lee Montgomerie and
Chris Terran took this superb picture of the Great Nebula in Orion (M42) with the
COAA 0.5m Newtonian. Chris and Lee know a thing or two
about image processing and you can see the full-scale
original of this beautiful
study on their web site devoted to Photodesk (a Photoshop-like graphics
package for RISC OS computers).
The Orion Nebula is a huge star-formation region where gas, mostly hydrogen, is collapsing
to form new stars. The news stars are very hot indeed and include a great deal of
ultra-violet radiation in their emissions. The UV ionises the gas in the cloud and
gives rise to these enchanting colours.
Regular Astroguest Fran Humphry, assisted by student volunteer Ben Scarrow,
used a low-cost colour web cam, modified in accordance with the design of Steve Chambers,
and the COAA 0.2m Newtonian telescope to capture these colour images of M57 (left) and
M27 (right). These two planetary nebulae illustrate how similar colours are created by
the radiation from the central white dwarf stars which shed the surrounding gas towards
the end of their active lives. Image capture and combining was done with the popular COAA
AstroVideo program.
As an exercise in minimalist astro imaging, student Ben Scarrow also took
this image of the constellation Cygnus (left - North is to the left) using the web cam's own tiny lens. Ben used
AstroVideo to create an exposure of 60 seconds. Stars down to about 8th magnitude can be
seen on the original image and the North America Nebula (NGC7000) can also be discerned.
The camera was simply placed on the ground, looking upwards, with no tripod and no
sidereal drive. With such a wide field of view, star trailing is hardly evident, even
with a 60 second exposure. Ben took a whole set of such images and then made an AVI movie
showing the motion of the stars across the sky. Unfortunately the AVI file is too large
to present here. Bear in mind that this whole imaging enterprise used no telescope, no
drive, merely the web cam and its own built-in tiny lens. It is remarkable what can be
achieved without employing any of the sophisticated equipment available at COAA.
Perseid Meteor Party
On the night of 12 August 2002 we held our annual Perseid Meteor Party. 45 visitors from many different countries enjoyed a splendid buffet supper followed by celestial entertainment from the abundant bright meteors emanating from the area between Cassiopeia and Perseus. In addition to visual observing, two of our AstroGuests were photographing the meteors and we also used the COAA SX CCD camera with a wide angle lens to capture meteor trails. The camera was pointed at the western side of Cepheus and special software was used to select from the many CCD frames, those with meteor trails on them. By subtracting a reference image with no meteors on, even faint meteors could be seen on many of the images. This Perseid (left) was caught by the camera while the radiant was still very low in the sky. The bright stars are alpha and beta Cephei.
We also used the COAA radio meteor detection software, R_Meteor, which detects meteor plasma by detecting the doppler shift of scattered radio energy from a TV transmitter near Seville. One of the more spectacular pings was this one (above) which shows a plasma trail which took three minutes to disperse. The radio record confirms that there were plenty of bright meteors but fewer faint ones.
The distinctive colour of Antares (alpha Scorpii) is well protrayed in this image. Dschubba (delta Scorpii), the brightest star to the right of Antares, is usually comparable in brightness to Graffias (beta Scorpii) which is just above it, but as can be seen here, it has almost doubled in brightness over the past year. The picture also includes many Messier deep-sky objects including M7, the most southerly object in the Messier catalogue, which is a hazy patch up and to the left of the tip of the 'sting' of Scorpius and M8, the Lagoon Nebula, visible as a pink glow up and to the right of the 'teapot' asterism of Sagittarius. The local meridian is in the centre of the photograph. The sky glow in the lower left of the photograph comes from the town of Portimão, with a population of about 30,000 and situated about 10 km southeast of COAA. Even in this area of sky, the C-shape of Corona Australis can be plainly seen beneath Sagittarius.
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Not everything in the sky is astronomy! This movie was taken with the COAA 0.15m Newtonian pointing at the five Hotbird TV satellites. Stars can be seen streaming past the group of satellites. Multiple satellites at a single station are used for redundancy and to share the programming load. Seeing these flying in formation through the eyepiece of the larger scopes usually provokes a startled reaction in those not expecting it.
Well-known astronomy author, presenter and broadcaster Paul Money, took this wide angle picture of Scorpius and Sagittarius at COAA. Much of the lower part of this picture is never visible from the latitude of central Britain.
On 2002 May 22, AstroGuests Chris and Dave Brockley took this superb image of the galaxy M82 in Ursa Major. The image was made using the COAA 0.2m
Newtonian telescope and the SX CCD camera. Chris and Dave made a set of unfiltered images and also a set of images with red, green and blue filters. Together with associated dark frames and flat fields, the images were combined using the COAA SX software and the LRGB set combined with the COAA FitsX software. This interesting galaxy is catalogued as an irregular galaxy and the conspicuous red colouration of the central region indicates that star formation is under way.
On 2002 May 14, AstroGuests Chris and Dave Brockley took these
striking pictures of two sunspot regions using the COAA 0.2m
Newtonian and a modified webcam. The telescope was capped by an
aluminised mylar filter. The images were captured by the COAA
AstroVideo software and processed by the COAA FitsX software.
During
March 2002, almost every visitor to COAA asked to see the Comet
Ikeya-Zhang 2002/C1. This delightful comet reached naked eye
visibility although the moonlight detracted somewhat from the
spectacle. Although it was not well-placed for observing with our
main instruments, this image was taken with a 50mm camera lens
and the COAA SX camera. North is to the right and the bright star
close to the comet is 91 Psc. The tail of the comet can be seen
to extend more than 5 degrees across the sky.
In the early morning of 2001 September 08,
Titania, a moon of Uranus passed in front of a 7th magnitude star
in Capricorn. The shadow of the moon passed over COAA and this
animation (right) shows selected frames from a three minute video
recording made using the COAA 8" Newtonian and a low-light
video camera. In this animation, north is at the bottom, the
brighter object is Uranus, the star is the fainter object and
Titania is too faint to show. By examining the recording frame by
frame, it was possible to time the disapearance and reappearance
to a fraction of a second. Events such as these provide much more
accurate positional measurements than conventional astrometry.
Portuguese amateur
astronomer Alfredo Pereira discovered a nova in Sagittarius on
the night of 26 August using nothing more than binoculars and an
astonishing knowledge of the night sky. On the following night,
student Ben Scarrow captured the image of the nova contained
within this animation. Using the COAA 0.5m Newtonian together
with a simple low-cost, low-light video camera Ben integrated 200
video frames in real-time using the COAA AstroVideo software to produce the image showing stars down
to 13th magnitude. The alternate frame in the animation was
synthesised from stars in the GSC catalogue.
AstroGuest Robin Emley, son of the lunar
specialist whose name is attached to one of the craters on the
Moon, used a video camera mounted on the COAA 12" Dobsonian
telescope to capture this image sequence (right) of the
International Space Station with the Space Shuttle STS-105
attached to it. The spacecraft was tracked manually and the video
recording was analysed to find a series of frames in which the
station was reasonably steady in the picture. The animation
covers around three minutes of elapsed time during which the
aspect of the station is clearly changing.
The Perseid
meteor shower put on a splendid show on 12 August. Between 50 and
60 people took the opportunity of an open night at COAA to enjoy
the meteor shower under dark skies. As well as a visual count of
meteors and a recording of meteors visualized by radio scatter,
we made a series of CCD images of a portion of the sky in
Cepheus. In around 80 images, each covering 12 by 10 degrees of
sky, we captured the trace of 8 Perseids. The one shown here (at
left) starts in the field of view. The radiant is at upper left
and the two bright stars are zeta and eta Cephei.
With the Milky
Way on the meridian in high summer, regular astroguest Gordon
MacKenzie, aided by student volunteer Chris La Brow, used the
COAA SX CCD camera and colour filters to capture this splendid
colour image (right) of M20, the Trifid Nebula, on the 8"
Newtonian. Gordon used the COAA FitsX software, featuring the
LRGB method of colour synthesis, to combine the colour
separations. As well as the familiar red bright nebula region
glowing with ionised hydrogen, the image clearly shows the blue
reflection nebula to the north which is caused by fine dust
scattering the light from nearby stars.
Using the same equipment and the same technique
but this time on M17, the Swan Nebula, in Sagittarius, regular
astroguest Will Hunter produced this superb colour image (left).
Gordon MacKenize also captured this colour
composite of M16, the Eagle Nebula (right), made famous by the
Hubble image entitled 'The Pillars of Creation'. The three dark
plumes can be seen in the centre of the nebulosity. Like the
other nebulae illustrated here, the Eagle is a region where stars
are forming. The UV radiation from the young stars causes the
hydrogen gas to fluoresce and create these beautiful images.
Gary Humphry
used the COAA 8" Newtonian and the SX CCD camera to capture
this beautiful montage of M8, the Lagoon Nebula (left). To cover
the large object, Gary, aided by Chris La Brow, took a matrix of
four images around M8 using red, green and blue filters and no
filter. The four image tiles were then seamlessly montaged into a
single image for each colour, using the COAA FitsX software and
the final full-colour result was synthesised from the LRGB
components.
Near-Earth-Asteroid
1999KW4 swung past the Earth on the night of 2001 May 26 at a
distance of only 0.03 AU. Although normally exceedingly faint, at
this close range it brightened to 11 magnitude. What was most
impressive was that the rapid motion of the asteroid was easily
detectable at the eyepiece of the COAA 0.5m Newtonian. Scientists
using radar techniques on the Goldstone radio telescope confirmed
what had already been suspected from the unusual light curve of
the object, that the asteroid is, in fact, a double. We captured
this animation (left) using the COAA SX CCD camera and 8"
Newtonian. Each contributing exposure in the animation was 60
seconds. The trail during this time illustrates the rapid
movement of the asteroid. Setting the COAA Telescope Controller
to track the asteroid, rather than sidereal rate, produced this
image (right) with a 60 second exposure.
AstroGuest Colin Keen took advantage of the
latitude of COAA to capture this superb image of Omega Centauri,
the largest globular cluster in the sky. Omega Centauri is so far
south that it can only be seen from the most southerly points of
Europe. Colin used the the new computer-controlled 8"
Newtonian telescope. The image is the sum of five one-minute
exposures using the Starlite Xpress CCD camera.
Astroguests Dave
and Chris LaBrow also used the new 8" Newtonian to image
this remote quasar in Camelopardalis (S4 0636+68) which has a
red-shift of over 3. The image is the sum of five one-minute
exposures taken with the Starlite Xpress CCD camera. The quasar
is indicated by the vertical lines; North is at the top and the
image size is 25 x 18 arc minutes. The image is displayed in the
negative to improve the visibility of faint objects. The
red-shift of S4 0636+68, z=3.177, corresponds to a distance of
12,000 million light years assuming a Hubble Constant of 73 km/s
per Mpc. This is around 90% of the way to the edge of the
observable universe or, expressed another way, 90% of the time
back to the Big Bang. To put this in context, the photons that
made the tiny mark on the image had accomplished more than half
their journey here before the Sun was formed...