180 Degrees

August 9, 2015 by grahamrob in Comments, General Astronomy, Viewing, Widefield Imaging and tagged Photography | 2 Comments

Viewing from Fairvale Observatory is far from ideal but I have no choice and need to make the most of it:

(i) Without going down the garden (which is not practical and would then totally obscure the southerly view) my house blocks the entire northern sky, critically including Polaris;

(ii) We have very high +/-12ft hedges surrounding the garden;

(iii) Directly east is a large house that completely obscures the horizon;

(iv) South east and south are very large trees;

(v) To the west is a wooded hill, thus blocking the horizon in that direction, and

(vi) Some 7-miles to the south is Gatwick Airport which produces significant light pollution, as well as aircraft that regularly fly through my images as well as others from Heathrow, also not far away.

It’s a miracle I am able to undertake any astrophotography and I long for the day I live somewhere with better conditions.

In the meantime I have to make do with the 180^o I have available. For the record and with great skies and good weather, this week I compiled a photo mosaic of the aforesaid view – which illustrates some of the aforementioned problems and is in itself an interesting picture. The scene is stitched together from six DSLR shots that encompass most of the east to west panorama but in order to achieve this, the resulting photograph becomes severely distorted.

The principal view is directly south, with the Meridian pretty much straight ahead. Low angle viewing and imaging is almost completely impossible but depending on the timing and some crafty shooting, the mid-angle objects can be accessed as they pass between the trees. The best imaging is therefore mostly restricted to a 20^o range between about 65^o and 85^o and within +/- 20^o of the Meridian; high angle east and west views are feasible but seeing in these directions is impacted by the greater atmospheric distance through which the light has to travel.

For now this is my night time playground: it is challenging and can be frustrating but with clear skies, preparation and patience it’s good fun and much can still be achieved.

Night sky panorama from Fairvale Observatory + obstacles: the tree on the left is very large +200 year-old copper beech, the coniferous trees due south are closer to the property boundary - thus increasing their impact on seeing. The red line on the left approximately marks the East and the central red line is the Meridian.

180 degree night sky panorama from Fairvale Observatory + obstacles: the tree on the left is a very large +200 year-old copper beech, the coniferous trees due south are closer to the property boundary – thus increasing their impact on seeing. The red line on the left approximately marks the East and the central red line is the Meridian.

Equivalent Cartes du Ceil planetarium view at the same time.

By Jove

July 27, 2015 by grahamrob in Imaging, Solar system, Uncategorized, Widefield Imaging and tagged Jupiter, Planetary Imaging, Solar system | Leave a comment

As a visual and photographic spectacle, in my opinion Jupiter comes a close second to Saturn among the planets. The so-called ‘King of the Planets’, Jupiter is more than twice as massive as all the others combined. Notwithstanding its size, Jupiter has the shortest ‘day’ of any planet, rotating fully in just 9-hours and 50 minutes – as a result creating a significant equatorial bulge that measures 88,760 miles in diameter and 83,082 miles from pole-to-pole. However, as a gas giant the planet does not rotate en masse, with the outer regions moving slower than the equatorial region leading to a series of distinctive belts and zones, most notable of which is the Great Red Spot – a massive storm on the edge of the South Equatorial Belt.

Partly because of its vast size and resulting gravitational field, Jupiter is thought to have played a dominant role in shaping the present Solar System. The planet we see today is not alone, with 67 moons so far identified, the four largest discovered by Galileo 400 years ago being easily visible from Earth. In order of distance from Jupiter the moons of Io, Europa, Ganymede and Callisto are extremely diverse in nature – ranging from the highly volcanic Io to the frozen world of Europa, whilst Ganymede and Callisto may have sub-surface oceans and are bigger than the planet Mercury.

Despite being by far the largest planet in the Solar System and the fourth brightest object after the Sun, Moon and Venus, my attempts to image Jupiter and its Jovian neighbours have so far met with only mixed success.

Most people’s first view of Jupiter is likely to be through binoculars or a basic telescope, which will show the very bright planet accompanied by a number of its Gallilean moons, depending on their orbital position i.e. when located behind the planet they will, of course, not be visible. Having viewed Jupiter a few times like this, my first attempt to image the planet and its moons was just such a view simply using the William Optics 81mm refractor, a x2 Barlow and my Canon 700D DSLR. Compared to Jupiter the moons are not as bright and to capture their presence it is necessary to boost either the ISO or exposure time, which then overexposes the bright planet resulting in loss of detail – in this case the distinctive coloured gas bands. Conversely, with a lower ISO or exposure this detail once again becomes apparent but some or all of the moons are then lost in the image. The way round is to combine two sets of images taken at different camera settings, thus obtaining the best of both worlds, literally. For the moment however this remains work in progress.

January 2014, Jupiter – overexposed but shows all four Gallilean moons | 1 sec @ ISO 400

Jupiter – lower exposure shows the gas belts but the moons, though there, are now very difficult to see. 1/3rd sec @ ISO 800

Personally I like the wider view of Jupiter and its moons but inevitably the holy grail has to be a close-up image showing details of the planet’s characteristic gas belts, which requires the use of a CCD video, in my case a ZWO ASI 120MC camera. Having mostly concentrated on DSO photography to-date using a DSLR, my use of the ZWO camera is limited and with mixed success. Using this camera and the Skywatcher 150PL reflector telescope I have previously managed images of Saturn, Mars and the Moon but this time I used the William Optics refractor instead.

CCD imaging is a very different technique to DSLR and it’s fair to say that I still have much to learn. Notwithstanding, using Registax for processing I obtained some reasonable first-time Jupiter images but will need more practice to improve the detail; the quality might also be improved using WinJUPOS software during processing, which applies a de-rotational programme to the fast moving planet thus reducing blur – however, I have yet to understand let alone master this software. Also, whilst the quality of the William Optics telescope is far superior to the Skywatcher 150PL, it is obvious that its relatively short focal length is not really adequate for good planetary imaging.

21st February 2015. Jupiter up close
WO 81GT81 | ZWO 120 MC

So far this year Jupiter had already provided a number of different opportunities for imaging. Between February and April the planet moved across the southern sky in all its glory, whilst more recently it moved into close conjunction with Venus at the end of June and there’s more to come.

On 26^th August from our vantage point on the Earth, Jupiter will appear very close to the Sun in the sky as it passes around the far side of the solar system from the Earth. At closest approach, Jupiter and the Sun will appear at a separation of only 0°52′, making Jupiter totally unobservable for several weeks while it is lost in the Sun’s glare. At around the same time, Jupiter will also be at its most distant from the Earth – receding to a distance of 6.40 AU – since the two planets will lie on opposite sides of the solar system. Over following weeks and months, Jupiter will re-emerge to the west of the Sun, gradually becoming visible for ever-longer periods in the pre-dawn sky. After around six months, it will reach opposition, when it will be visible for virtually the whole night, by which time I have hopefully mastered some new techniques for imaging this Jovian King of the Planets.

Canon Koppernigk’s Conjunction

July 3, 2015 by grahamrob in General Astronomy, Solar system, Viewing, Widefield Imaging | 5 Comments

This time of the year is something of a fallow period for astronomers: short nights combined by with the complete absence of astronomical darkness and fewer DSOs. I have personally found this year more difficult than usual as since April 25^th, following an operation to replace my left knee, I have been physically unable to set-up Fairvale Observatory and undertake astronomy of any sort. Notwithstanding, once over the initial few weeks of pain, I have tried to use the extra time afforded me usefully.

I have been reading Arthur Koestler’s excellent book The Sleepwalkers, which charts the history of man’s understanding of the universe and astronomy. Speaking of fallow periods, in the book I’m just past the very long period of inactivity and general superstition regarding the cosmos that occurred during the Middle Ages, which followed the more enlightened thinking of the Greeks, particularly Pythagoras; taking account of the Greek’s progress in understanding the Universe, our astronomical knowledge might have been 1,500 years more advanced today were it not for this prolonged medieval hiatus! Fortunately Copernicus (his better known Latin name) finally initiated what has become today’s heliocentric model of the Solar System, although his seminal work On the Revolutions of the Heavenly Spheres was only published just a few hours before his death after a delay of 30-years, such was his reluctance to put forwards such thoughts at that time.

Next, I have just completed the 6-week AstroTech MOOC course organised by Edinburgh University, which covered the scientific logic behind astronomical discoveries and the technology that lies behind them. This was my third astronomy MOOC and provided some interesting insight into telescope and imaging technology, as well as filling time during my recovery.

Finally, as my (limited) mobility has slowly started to improve, the night sky has recently provided a fascinating show of its own that did not require the observatory’s paraphernalia and, furthermore, beautifully demonstrated the principles originally outlined by Copernicus in 1543.

During the latter part of June Venus and Jupiter moved inexorably towards very close conjunction by the end of the month. Reaching just under ¾ of a degree separation on 30^th June and 1^st July this is a rare event, which with a clear sky could be easily viewed with the naked eye. Better still, I set out to photograph the two planet’s journey during the preceding 12 days, thus illustrating Copernicus’ revolutions around the sun of these two heavenly spheres. Whilst any school child will today understand this process, it is a frightening thought that belief in such a mechanism could once have led to the death penalty!

Obscured from view at Fairvale Observatory as Venus was just 17 ½^o above the western horizon, I had to travel to a nearby location which provided a clearer westerly viewpoint of both planets at their low attitude. In order to obtain a series of comparable images and thus show the real spatial changes occurring up to conjunction, all pictures were taken from exactly the same location. With my Canon EOS 700D fixed on a photographic tripod I shot a series of images over a 50 minute period using either the 18mm or 55mm telephoto settings, playing with ISO and speed settings as darkness progressed; this was roughly the time the two planets took to disappear below the Earth’s horizon after achieving Civil Darkness.

The resulting photographs show Jupiter apparently advancing on Venus before at conjunction ‘passing’ close by on the aforementioned days. Whilst Jupiter is the third brightest object in the night sky (after the Moon & Venus) and nearly 12 times the size of Venus or 1,400 times by volume, the planet looks very small by comparison to Venus. This of course is the effect of perspective, with Jupiter currently some 565 million miles distance from Earth, whereas Venus is only 48 million miles; furthermore although at -1.8 the apparent magnitude (brightness) of Jupiter is high, at -4.4 Venus is much brighter.

18th June 2015: Jupiter left, Venus right – trees on the horizon provide a reference scale as the planets move towards each other during the month in subsequent photographs.

25th June 2015 + 7-days

30th June 2015 + 5 days. Nothing – dark thunder clouds completely obscure the western sky during conjunction!!!

1st July 2015. Bingo = conjunction; though one day later Jupiter has now moved to the right of Venus.

1st July 2015. Close-up of the conjunction using 55mm telephoto setting and ISO 400 - Venus now left & Jupiter right.

1st July 2015. Conjunction close-up using 55mm telephoto setting and ISO 400 – Venus now left & Jupiter right.

Unfortunately I am expecting it will be at least another month before I have recovered sufficiently to consider setting-up Fairvale Observatory again, by which time Astronomical Darkness will thankfully be slowly returning. In the meantime I’m looking forwards to the next section of The Sleepwalkers which covers Kepler and Galileo and hopefully exciting developments from the New Horizon Pluto fly-by and more from the Rosetta Mission and the re-awakening of its Philea lander. Given clear skies there should also still be plenty to see without the observatory: The Perseids, Saturn and of course at the centre of our Solar System as determined by Copernicus, the Sun, which will be at aphelion on 6^th July – though you wouldn’t think so judging by the high temperatures currently prevailing in the UK and Europe!

Spring Skies

April 12, 2015 by grahamrob in Deep Sky Objects, Imaging, Solar system, Widefield Imaging and tagged Pleiades, Taurus, Venus | Leave a comment

It’s three weeks since the Spring Equinox and two weeks since moving to British Summer Time (BST or daylight saving, GMT+1 hour), the result is that the night sky starts much later in the evening and is rapidly decreasing in length; it is just about six weeks before Astronomical Darkness completely ceases and will not come back until the end of July. In addition, through a combination of European pollution and fine sand from the Sahara drifting over South East England this week, otherwise clear skies were badly obscured by the resulting haze. As a result, since shortly before the full Moon on April 4^th astronomy has not been possible – until last night.

The march of time and annual movements of the Solar System inevitably lead to a significant loss of quantity and quality of darkness at this time of the year.

Taken this morning, the contrails over Fairvale Observatory make a striking picture but together with other pollution are having a significant impact on seeing conditions here at the moment.

In the early evening twilight sky for a brief period between sunset and astronomical darkness, at the moment Venus is low on the western horizon. Last night its apparent position was also close to the Pleiades star cluster, making an attractive widefield photograph. Furthermore, shortly before Venus moved below the horizon and the sky had nearly reached Civil Darkness, the constellation Taurus also became visible to the south west with the bull’s ‘eye’ star Alderbaran and the v-shaped Hyades star cluster clearly evident.

Venus at sunset last night: the Pleiades can only just be seen at 2-o’clock to Venus with Taurus on the far left.

Twenty minutes after sunset shortly before reaching Civil Darkness, the Pleiades and Taurus constellation are now quite clear.

Such a picture is a reminder that it is important to consider photography other than telescopic based planetary and deep sky imaging, especially as viewing and imaging conditions become more limited over the forthcoming Summer period.

Alternative Eclipse

March 20, 2015 by grahamrob in Imaging, Solar system, Viewing and tagged Eclipse, Solar system, Sun | Leave a comment

With astronomy preparation is everything and so with the prospect of a solar eclipse here today I have been getting ready during the past week. I looked at and imaged the Sun using my Skywatcher 150PL and a bespoke solar filter last year. Whilst I was pleased with the results, such is the field-of-view of the 150PL that the resulting image only covers sections of the Sun and a full picture needs to be created using a mosaic; the upside of this is high magnification and therefore better detail of the Sun’s surface. With the prospect of an eclipse I wanted to try and image the entire spectacle this time and therefore constructed a new solar filter to fit my William Optics GT81 refractor telescope, which has a wider field-of-view and all together better optics that would comfortably image the entire Sun.

Using Baader AstroSolar ND 5.00 safety film and some cardboard, I constructed a tube which fits exactly over the end of the telescope, with the film across the front but not stretched. By restricting wavelengths the film removes about 99% of the Sun’s light and allows safe viewing but is very difficult to work with and must be treated carefully to ensure it is not damaged; birds can be attracted to the film’s silver finish and may peck holes in it when fitted, it is therefore important to be aware of such threats and, in my case, I also constructed a cardboard slip to cover the filter when the telescope is left unattended during use. It is also very important to either block off or remove the guidescope and / or finder from the telescope, which without a filter could otherwise also focus on the Sun and either burn out or even worse, cause personal injury.

Home-made solar filter on the William Optics GT81. When used I blocked-off the red dot finder and removed the finder scope in order to attach another home-made Sun finder.

The Players: having constructed the filter and with a clear sky on Wednesday I therefore tried it out and furthermore experimented with exposure settings, with good results. Earlier in the month I had captured an excellent image of the quarter Moon too. So I was ready to go, right? Wrong!

The Moon @ First Quarter | WO GT81 & Canon 700D + FF| 1/100th sec @ ISO 100 | 24th February 2015

GT81 + Canon 700D & Baader ND 5.00 Solar Filter
1/500th sec @ ISO 100 | 18th March 2015

The Sun 1/20th Sec @ ISO 100 | 18th March 2015

The Sun
1/250th Sec @ ISO 100 | 18th March 2015

Despite my best planning it was cloudy here at Fairvale Observatory this morning, something that has been proving a major obstacle to any astronomy all this month. Notwithstanding, I have instead experienced an ‘alternative eclipse’.

First, I recorded the change in light during the eclipse. Though ‘only’ an 85% eclipse here the deterioration in light was very noticeable as well as other features: it got colder and the birds became quieter.

20th March 2015 Eclipse - the sky just after contact at 9.50 a.m.

20th March 2015 Eclipse – the sky at 9.50 a.m. sky just after contact.

Contact + 15 minutes

At maximum 85% eclipse, 9.30 a.m.

Next I ‘looked’ at the progress of the eclipse using Google Sky, which seemed to be very accurate. It was fascinating to note that four other planets were lined up alongside the Sun at the same time, though of course would not be visible in the daytime sky even if it had been clear.

Eclipse as ‘seen’ by Google Sky

Google Sky screenshot.

In between my own real time experience, I watched the BBC coverage of the event which provided some excellent images from the UK and especially from the air off the Faroe Islands where totality occurred.

UK eclipse courtesy if the BBC.

Eclipse totality at 28,000 ft from the Faroe Islands.

Baily's beads in hydrogen-alpha image. Faroe Islands March 2015.

Baily’s beads hydrogen-alpha image. Faroe Islands March 2015.

Diamond Ring hydrogen-alpha image.
Faroe Islands March 2015

An eclipse is astronomy in action and inevitably I’m disappointed not to see and image the actual eclipse here but my alternative eclipse was still interesting and good fun. I was lucky to witness a total eclipse in France in August 1999 so that’s a 50% success rate so far. The next partial eclipse in the UK will be on 12^th August 2026 so I have time to prepare but, of course, will be unable to do anything about the weather again. Fingers crossed then I suppose!

Another perspective. Eclipse 2006, taken form the ISS the Moon's shadow passing over Turkey.

Another perspective. Eclipse 2006, taken from the ISS the Moon’s shadow passes over Turkey at 2,000 kph.

Big Cat Hunting

February 26, 2015 by grahamrob in Deep Sky Objects, General Astronomy, Imaging and tagged DSO Imaging, Galaxies, Leo | 1 Comment

As we move closer to the Spring Equinox, the winter sky is already rapidly disappearing towards the western horizon and I have been left wondering what next? I was concerned that after successfully imaging the Orion constellation and all its spectacular parts over the past four months, it would be a difficult act to follow, I needn’t have worried. Already starting to appear from late-evening, a series of constellations are about to proceed across the night sky over the next few months which will provide an equally spectacular but different kind of show to Orion.

First of these is the constellation Leo, the celestial Lion, which it turns out is packed with galaxies and double stars. The asterism of Leo is in the shape of a lion which, being dominated by various groups of galaxies holds much imaging promise, with my 81mm telescope providing an ideal field of view.

Located behind Leo’s rear ‘leg’ is the best of these, known as the Leo Triplet or M66 Group, which consists of three galaxies: M66, M65 and NGC 3628. Evidence suggests that these are linked in a gravitational dance with each other which, in the case of NGC 3628, has created a disturbed, unbarred galaxy with a faint 300,000 light-year star to the east. M66 is an intermediate spiral galaxy, with a diameter of about 95,000 light-years and is the largest and brightest of the trio. M65 is a smaller, barred intermediate galaxy. The field of view has also captured other galaxies as well as the orange giant star 73 N Leonis. All-in-all a wonderful image which I hope to return to in order to achieve even better detail using longer exposures, guiding and hopefully a larger telescope one day.

Leo Triplet: M66, M65 & NGC 3628
WO GT81 + modded Canon 550D & FF | 10 x 180 secs + calibration @ ISO1,600 | 21st February 2015

To the west of the Leo Triplet, in the direction of Leo’s dominant star Regulus, is another triple collection of galaxies called the M96 Group. While a little fainter that the Leo Triplet, the M96 Group nonetheless makes a wonderful image accompanied, as it is, by numerous other galaxies and stars. Of the latter, the giant orange 52 K Leonis star dominates the scene.

M69 Group: M105, NGC 3373 & NGC 3371 + other galaxies and orange giant 52 K Leonis WO GT81 + modded Canin 550D & FF | 10 x 180 secs & calibration @ ISO 1,600 @ 21st February 2015

M96 Group: M95, M96, M105, NGC 3373 & NGC 3371 + other galaxies and orange giant 52 K Leonis
WO GT81 + modded Canon 550D & FF | 10 x 180 secs & calibration @ ISO 1,600 @ 21st February 2015

It’s fair to say that the results of my big cat hunting around the constellation Leo have been a pleasant and successful surprise, with further promise still to come as Spring develops. Watch this space!

Inverting the M96 Group image helps show better the galaxies and other significant features.

Parting Shot

February 14, 2015 by grahamrob in Deep Sky Objects, Imaging, Software and tagged DSO Imaging, Nebulae, Orion | 6 Comments

I thought I was finished with Orion for this winter but a high pressure system and clear weather provided an unexpected opportunity on Sunday evening that I couldn’t resist. The good news: as Orion is passing the Meridian by 8.00 pm it provides an early start. The bad news: being near Gatwick Airport, at this time of the evening the sky is full of aeroplanes at Fairvale Observatory, most of them flying directly through the Orion field of view!

With such good weather, I also decided to try out computer control for the first time. I installed EQMOD before Christmas and have since been reading and watching tutorials on its use and experimented operating with it indoors. Frankly I am somewhat intimidated by the large collection of software that is required to go to the next level with imaging and EQMOD is just the first step. However, eventually I just have to do it and this would be the night to start!

EQMOD is a software project written and run by enthusiasts which provides computer control to the mount, thus dispensing with the SynScan handset. It also does much, much more and in general provides far superior control and flexibility, in particular linking control with a chosen planetarium programme – usually either the excellent Stellarium or Carte du Ciel, all of which is free!

Notwithstanding, I still have the major problem of polar alignment as my house completely obstructs all views of the northern sky. For the moment I adopted a belt-and-braces approach, first achieving polar alignment using the SynScan routine before switching to EQMOD control; once comfortable using EQMOD I plan to try out alignment software called Alignmaster, which I hope will allow me to completely dispel with SynScan. On this occasion EQMOD worked a treat. For alignment, just clicking on the object you want to see in the planetarium software (with which EQMOD is linked), the telescope slews and after accurately aligning the scope with the star you press a sync button. It’s so quick that it is easy to rapidly establish five or six (or more) star alignment points, thereby constructing a triangular matrix from which the mount can then track more accurately. There are many other features I have yet to use but so far I like what I see and am in awe of those who have written and maintain the system.

With EQMOD computer control thus established successfully, I set out to image some old ‘friends’ in Orion. Having only recently acquired a modded Canon 550D, it seemed only right to take another look at M42 the Great Orion Nebula and The Flame and Horsehead nebulae.

The impact of modification was immediately evident with M42, it now being much redder than before and with greater detail exhibited in the nebulosity. The tracking also looked OK, though a few stars looked a little bloated, suggesting there’s still work to do on another day i.e. autoguiding.

Orion’s Sword: M42 The Great Orion Nebula, Running Man Nebula & NGC 1981 Star Cluster
WO GT81 + modded Canon 550D & FF | 10 x 180 secs @ ISO 800 & darks calibration | 8th February 2015

The Flame and Horsehead nebulae also show similar improvements and, in the case of the Horsehead, the actual ‘head’ is much clearer than before.

NGC 2024 Flame Nebula & Horsehead Nebula WO GT81 + modded Canon 550D & FF | 10 x 180 secs @ ISO 800 & darks calibration | 8th February 2015

NGC 2024 Flame & Horsehead Nebula; NGS 2023 relection nebula just below/left of the Horsehead
WO GT81 + modded Canon 550D & FF | 10 x 180 secs @ ISO 800 & darks calibration | 8th February 2015

With Orion by now well past the Meridian and the weather holding up well I then decided to try my luck once again with Jupiter, which by now is well located high in the south east sky. Unfortunately like sport, astronomy is a game of two halves. Following the success using EQMOD my experience with Jupiter was a complete failure.

I had previously encountered significant problems with my webcam last year, that mostly stemmed from problems with the capture software and it was here that I was to stumble (fall more like it) once again. Initially Firecapture seemed to boot up OK and recognised the camera, though try as I may I could not see Jupiter on the screen; I knew it was there as I had previously centred and focussed it there. I therefore decided to reboot the software, which was a big mistake. This time Firecapture would not recognise the camera and on trying to de-bug the problem I ended up with the dreaded ‘black screen of death’. Here was the downside of computer control, with the black screen going nowhere I also lost all control of the mount! I therefore retreated to SynScan, parked the telescope and deliberately crashed the computer; I have not yet investigated the problem further since then – watch this space!

It was therefore something of an ignominious end to the evening. However, I was still buoyed by the earlier success of EQMOD and more than happy with what may be my parting shot of Orion for this winter. Au revoir.

Horsehead Nebula with the NGC 2023 reflection nebula, bottom left

Room With A View

February 12, 2015 by grahamrob in Comments, Imaging, Widefield Imaging | Leave a comment

The International Space Station is an amazing achievement and I consider the people who fly in the ISS to be very lucky.

From time to time the ISS flies over Fairvale Observatory and last Christmas Eve was such a moment when, travelling at just over 17,000 mph about 250 miles above Earth, I managed to get a picture of its trail in the sky.

ISS flies over Fairvale Observatory 24th December 2015

ISS flies over Fairvale Observatory
24th December 2014

Yesterday US astronaut Terry Virts currently onboard the ISS tweeted this fantastic picture of the British Isles from his vantage point above Earth, set-off by the Aurora Borealis to the north. Thanks Terry and good luck.

Orion in Perspective

February 6, 2015 by grahamrob in Deep Sky Objects, Equipment, General Astronomy, Imaging, Widefield Imaging and tagged Orion, Photography | Leave a comment

Perspective:

The appearance of objects relative to each other, as determined by their distance from the viewer, or the effects of this distance on their appearance – The Free Dictionary.

Noun: The art of representing three-dimensional objects on a two-dimensional surface so as to give the right impression on their height, width, depth and position in relation to each other – Oxford English Dictionary

I have just finished an Open University MOOC (Massive Open Online Course) on Orion, which it has to be said was mixed in its content and quality. Notwithstanding, the course provided a useful basic understanding of objects in the Universe, particularly Orion, how they related to each other and as a whole. Through my professional experience I am used to viewing and understanding objects in 3D, all the more so since computer modelling has provided a tool with which to visually illustrate such spatial shapes and relationships. Although it is obvious that such relationships also describe the astronomical space in which we exist i.e. the Universe, and commonly describe the location of stars and other heavenly bodies by their distance, RA and DEC, I have seen very few of these objects visually modelled for common asterisms or constellations.

The constellation of Orion is probably the main feature of the winter night sky and it is certainly my favourite, particularly when looking at its rich content: M42 the Great Orion Nebula, the Running Man Nebula, the Horsehead and Flame Nebulae, M78, Barnard’s Loop and many more. Sadly after more than 4-months imaging these objects for the first time, Orion is now starting to rise very early in the evening and by 11pm is well past the Meridian – it will not be long before this magnificent feature will be gone for another year, until on the very early mornings of next October it will reappear again, can’t wait!

With my new found interest in astroimaging I have almost exclusively used a DSLR camera and focused my attention on DSO features, using a telescope and GoTo mount, somewhat neglecting the use of the camera for basic widefield photography. Apart from the attraction of playing with my new toys, I was put off by the lack of a suitable camera attachment and a wide angle lens; because of the inherent crop factor associated with the cropped digital sensors employed in most DSLR cameras (except very expensive full frame cameras), the real focal length of a camera lens will be extended and hence the field-of-view narrowed – in my case with a x1.61 crop factor, a 50mm lens operates at an apparent focal length of 80mm! However, using the top off an old camera tripod I recently I managed to jerry rig the camera onto the GoTo mount, thus providing tracking and enabling longer exposures. It’s only a start but there is great promise in such photography, as seen on this excellent website, and I intend to pursue more of these images with a better way of attaching the camera and decent wide-angle lens when I can.

As a result, on Christmas Eve I obtained my first reasonable image of the whole Orion constellation, which with better exposure shows the detail, beauty and context of the numerous DSO items contained within and images previously noted.

The Orion Constellation Canon 700D | 27 x 10 secs @ ISO 1,600 & calibration | 24th December 2014

The Orion Constellation
Canon 700D & Telephoto 200 mm | 27 x 10 secs @ ISO 1,600 & calibration | 24th December 2014

In the early days of my astroimaging about 12 months ago, I found focussing something of a challenge but, with the assistance of the wonderful Bahtinov mask and Live View on-screen computer focusing, I thought that had become a thing of the past, unfortunately not! Guided by the infinity mark on the camera lens for focussing, I set out to image some of Orion’s more elusive nebulosity, in particular Barnard’s Loop, with which I am fascinated – its enormous size of some 10^oor 600 arcminutes and complete absence from ordinary view are both intriguing, exciting and challenging. I had tried to photograph this feature before, which completely envelops Orion’s Sword and extends up towards Betelgeuse, but to no avail. With my bodged but useable camera set-up I tried again two weeks ago. This time the problem was once again focussing; it turns out that with widefield astroimaging using a standard camera lens, infinity does not necessarily mean infinity, as there is some leeway either side. The out-of-focus images that resulted could therefore not be stacked but, using a single image, calibration and extensive post-process stretching in Photoshop, Barnard’s Loop was finally revealed and even Lambda Orionis above Betelgeuse and Bellatrix, albeit very noisy and out of focus. Notwithstanding, I am pleased with this enticing glimpse and will return another day to rectify the problems.

The Orion Constellation & Barnard's Loop (up / north is left) AZ-EQ6 Mount + Canon 550D & 200mm Telephoto | 180 secs @ ISO 1,600 & calibration | 22nd January 2015

The Orion Constellation & Barnard’s Loop (up / north is left)
AZ-EQ6 Mount + Canon 550D & Telephoto 200 mm | 180 secs @ ISO 1,600 & calibration | 22nd January 2015

Since my first decent image of the Great Orion Nebula on a very early morning at the beginning of last October, I have had hours of fun and some frustration imaging various parts of the Orion Constellation. But despite my new familiarity with the Orion constellation, 3D modelling and, I’d like to think, good spatial awareness, I was still pleasantly surprised and impressed by this wonderful 3D video of the constellation produced by the Space Telescope Science Institute for NASA and used during the aforementioned Open University course, which really does put it all into perspective: The True Shape of Orion.

Busy Bees

February 1, 2015 by grahamrob in AstroBin, Deep Sky Objects, Imaging and tagged Cancer, DSO Imaging, Star Clusters | 1 Comment

Cancer AKA the Crab, is the dimmest of the zodiacal constellations and generally lacking in notable objects except, at its centre, lying almost on the Ecliptic just 600 light-years from Earth, M44 is one of the closest star clusters to the Solar System. More engagingly, M44 derives its alternative name from its appearance as a swarm of stars dancing actively like bees i.e. the Beehive Cluster. Its Latin equivalent, Praesepe means hive, manger or crib.

At 600 million years old its dancing stars must be considered quite youthful compared to our Sun’s 4.5 billion years and are thought to have been created from the same, very large molecular cloud as Hyades in the constellation of Taurus. An open cluster of some 1,000 stars, M44 spans 15 light-years across or about 1.5^o. A few but distinctive yellow-orange tinted red giants stand out, scattered amongst the brighter hot blue stars, making an attractive image, one I expect to return to during the next three or more months as The Crab shuffles westwards across the night sky before giving way to views of a Spring and Summer nature.