Harvest Time

September 30, 2015 by grahamrob in Imaging, Solar system and tagged Lunar Eclipse, Moon, Photography | 2 Comments

Thanks to Copernicus and Kepler et al, astronomical events are highly predictable; unfortunately the same cannot be said about the weather. Since taking up astronomy and despite favourable predictions of clear skies, I have frequently been thwarted by incoming cloud or worse. When communicating with each other astronomer’s often use the closing of “Clear Skies”, no wonder given the continuous battle we have just to see the sky at night, let alone image it!

Such was my experience in 1982. At the time I lived and worked in northern South Africa, close to the border with Botswana and the Kalahari Desert. A lunar eclipse was forecast and in this part of the world there was usually a good chance of a clear sky. Unfortunately, it was not to be this time either. We saw glimpses of the eclipse through brief gaps in the otherwise thick cloud that was blowing across the sky. I’ve missed other eclipses for the same reason, lunar and solar, and as a result have developed a somewhat resigned mindset towards such events, with the probability that the sky would most likely not be clear. And so despite encouraging forecasts, my expectation for this week’s lunar eclipse was more of the same.

The lunar eclipse of 28^th September was very unusual. At mid-eclipse the Moon was just one hour past its closest approach to Earth in 2015, creating an effect now popularly termed a ‘Supermoon’. Moreover, the rare combination of this and a full eclipse at the same time results in a distinctive red moon at totality.

I have learnt the hard way that in astronomy Rule-1 is perseverance. I therefore carried out all the necessary research on the eclipse, undertook a dry run the previous evening and set-up all the equipment in the early evening before heading for forty winks – it was after all hopefully going to be a long night. The weather had been clear and sunny earlier in the day but was forecast to cloud over shortly after midnight, just before umbral contact! The sky was clear when I went out later but ominously there were clouds in the west. Notwithstanding, the sky remained clear all night and the eclipse was nothing less than spectacular.

Total Lunar Eclipse 18th September 2015

The precision with which astronomical events are plotted is incredible and, guided by various articles and charts all was in place well before the end of the penumbral stage at 2.07am. Shortly before darkness started to show on the top, eastern edge of the Moon and then exactly at 2.07am the eclipse shadow touched and then crept inexorably across the Moon’s surface. This was the main phase of the eclipse when the Moon enters the central, dark part of the shadow called the umbra, eventually reaching totality at 3.11am.

Totality lasted 1 hour 12 minutes, during which I just watched through a pair of 10 x 50 binoculars, which probably was the best way of actually viewing the Moon throughout the eclipse. Of course, with the brightness of the full Moon obscured by the eclipse during this time, the rest of the night sky was plunged into blackness, thus bringing the stars, nebulae and galaxies back to life. As the Moon was passing through the lower part of the Earth’s umbral shadow, the southerly edge appeared relatively bright during much of totality. Totality finished promptly at 4.23am as the light started to move across the Moon’s surface once again like an unstoppable wave. The Moon finally exited the umbra at 5.27am and the show was over until October 2033, on which occasion the Supermoon eclipse will unfortunately not be visible from the UK – I did say it was rare. However, there will be another total lunar eclipse in July 2018, so it’s not all bad news.

Given my history, this was naturally my first time imaging a lunar or any other eclipse and I am very pleased with the results. Other than requiring a clear sky, as usual preparation was the key: understanding the timing and dynamics of the event and considering the imaging possibilities. The most obvious problems to overcome were the Moon’s tracking and movement of the eclipse itself, with its associated impact on changing brightness and contrast for imaging.

The previous evening had also been clear, so I tested a basic DSLR + tripod set-up using an intervalometer to trigger the shots at 5-minute intervals. With the 200mm telephoto lens 8 pictures were successfully recorded as the Moon tracked across the image frame, at 100mm this increased to 12 pictures; however, the track tended to move out of the side of the frame early as the Moon follows an inclined rather than horizontal track. Altogether it was a successful and useful experiment for the next evening.

On the night I used the William Optics GT81, with a Canon 550D camera and field flattener, which continuously tracked the Moon and eclipse, imaging at 1-minute intervals throughout the period inward and outward of the umbra and manually during totality. Using a fixed ISO 100, it was necessary to continually change the exposure time every five or so minutes in order to compensate for the aforesaid changing light conditions. In addition, I again used the intervalometer with the Canon 700D and the 55- 250 mm telephoto lens on a camera tripod.

Eclipse: Inward sequence from umbral contact to totality WO GT81 + Canon 700D + FF | 1/500 to 1/3 sec @ ISO 100 | 18th September 2015

Eclipse: Inward sequence from umbral contact to totality
WO GT81 + Canon 550D + FF | 1/500 to 1/3 sec @ ISO 100 | 28th September 2015

Eclipse: Exit sequence to full Moon Canon 550D + tripod | >=1/160 sec @ ISO 400

Eclipse: Exit sequence to full Moon
Canon 700D + tripod | >=1/160 sec @ ISO 400

Eclipse animation

The results from both methods turned out well. With superior optics and tracking, the WO telescope images were naturally better in quality and magnification. However, the alternative simple camera set-up also produced a pleasing record of the eclipse, perhaps in some way capturing the mood better?

The entire event lasted just over 3-hours, during which found it necessary to look away from the imaging process at times just to enjoy this unusual and exciting spectacle. The name Harvest Moon is given to the full moon closest to the Autumn Equinox, recognising the time of year at which the crops have been gathered and can itself be an attractive sight. The coincidence with an eclipse makes for a rare and dramatic occasion, which this time I was able to enjoy completely cloud free from beginning to end – well that’s a first.

Harvest Moon at Totality WO + Canon 700D + FF | 1/3rd Sec @ ISO 400 | 28th September 2015

Harvest Moon at Totality
WO + Canon 550D + FF | 1/3rd Sec @ ISO 400 | 28th September 2015

The Pelican & The Phoenix

September 22, 2015 by grahamrob in Deep Sky Objects, Equipment, Imaging and tagged Cygnus, DSO Imaging, Nebulae | 2 Comments

As we pass the Autumn Equinox the promise of long and exciting Winter skies is not far off but there are still some wonderful late Summer features around worth imaging before they move away from the Meridian and out of view from Fairvale Observatory. Following a major operation earlier in the year I’ve been unable to move the heavy equipment outdoors until very recently and have therefore almost completely missed the Summer skies; even as I’ve been getting better in recent weeks, poor skies and other circumstances have stopped my return to astronomy – until now.

Up until shortly before midnight the Cygnus constellation is favourably located close to the Meridian at the moment and at a very high, southerly altitude – perfect for my location – it was therefore here that I chose to make my long awaited resumption to astroimaging last Saturday. The weather forecast in the morning showed clear skies for that night but by early evening had changed to cloud and looked like being another lost opportunity; on this basis the Flamsteed Astronomy Society had already cancelled their planned evening astronomy session. However, unlike previous attempts in recent weeks when clear skies were forecast and the cloud rolled in unannounced, this time the outcome was very different, with a clear moonless sky throughout the night – I sometime wonder if the weather forecasters have windows and bother to look outside!

Located northeast of the first magnitude star Deneb and some 1,600 ly from Earth is NGC 7000 or the North America Nebula, an enormous H II region that in outline resembles the North American continent. I first encountered this emission nebula at a similar time last year, which was my first experience of such a feature and I was therefore thrilled to capture part of it in my picture; my blog title at the time captures my feelings – WOW! However, taking the image using the longer focal length Skywatcher 150PL with a smaller field-of-view (FOV), the picture only captured part of the ‘USA’ and the ‘Gulf of Mexico’. Furthermore, using an unmodded camera much of the red H-alpha light that is characteristic of these nebulae was not recorded.

Since then my equipment has changed in a number of important ways, so that the William Optics GT81 with a wider FOV would now enable me to image more of the nebula, whilst using a modded DSLR camera would also record much more of the H-alpha light; an additional year’s experience also helped. This time my target was the related IC 5070 and IC 5067 H II regions otherwise known as the Pelican Nebula, situated just west of NGC 7000 and close to Deneb.

The Pelican Nebula, IC5070 & IC 5067. WO GT81 & modded Canon 550D + FF | 30 x 120 secs @ ISO 1,600 + calibration | 19th September 2015

The Pelican Nebula, IC5070 & IC 5067
WO GT81 & modded Canon 550D + FF cropped | 30 x 120 secs @ ISO 1,600 + calibration | 19th September 2015

With an apparent magnitude of +8 the Pelican is generally less bright than its larger +4 neighbour but is no less exciting. The bright double star Cygnus 57 and binary Cygnus 56 shine conspicuously just in front of the ‘bird’ and within the ‘body’ respectively. In addition a bright area at the northern top of the ‘bird’s head’ is an active area of star formation, which ionizes the gases creating the glowing red area.

Whilst missing the impact of being my first H II nebula last time, the larger image of the North America Nebula now captures most of the ‘continent’ and encompasses ‘Central America’. As a result the picture clearly shows the Cygnus Wall, another bright area of star formation that runs along ‘Baja California’ / ‘northern Mexico’ area.

NGC 7000 The North America & Pelican Nebulae
WO GT81 + modded Canon EOS 550D + FF | 30 x 120 secs @ ISO 1,600 + calibration | 19th September 2015

The combined Pelican and North America Nebulae span some 50 ly across, which when imaged together makes a wonderful picture of these spectacular features. I would be happy with this image at any time but after nearly six months away from astroimaging it’s a very pleasing result. I feel re-invigorated, like the phoenix has risen again.

Fly me to the dark side of the Moon

September 15, 2015 by grahamrob in Earth, Solar system, Widefield Imaging and tagged Moon | 3 Comments

I am still struggling to return to astronomy – no longer hampered since July recovering from my knee operation, which though stiff and painful is slowly improving, but now by the weather, a one-eyed cat, my own incompetence and inevitably the Moon.

Taking care of my daughter’s cat in early August, ruled out astronomy as the unfortunate one-eyed cat is not allowed outdoors, thus making the movement of equipment freely in and out the house very difficult. The weather then turned bad before it was time for the full Moon at month end, itself an imaging opportunity, except once more for the presence of thick cloud cover. Shortly afterwards clear nights were forecast but twice after setting-up the equipment under a clear sky the clouds rolled in again. Finally a week ago under a moonless clear sky, I completed the equipment set-up and turned on the mount in order to start the alignment and camera set-up sequences.

I’ve owned the current equipment since last July and after months of busy use felt I was now familiar with all the basic procedures – wrong. Because of my operation it’s been five months since using the equipment and after going through the initial SynScan sequence I started the alignment routine, only to find that each time the scope slewed to exactly 90⁰ east of the target star. I diligently repeated the start-up routine a number of times but with the same result – bizarrely on switching to EQMOD linked with Carte de Ciel, the scope moved correctly to the chosen star. It seemed there was an obvious answer to the problem but I could not work it out and in the end had to give up, missing a great opportunity as the sky continued clear all night – talk about frustrating!

The next morning I went through the complete mount set-up and SynScan start-up routine again, with a clear head and some guidance from SGL members, it took me about 10-seconds to find the problem – I had input the date as day-month-year instead of month-day-year; in this case 06/09/15 was exactly three months or one quarter earlier than the correct date input of 09/06/15, the sky equivalent of 90^o. Why is it in the 21^st Century that an advanced technologically advanced country such as the USA, uses an uncommon date format and imperial units, they even mix-up themselves and as a result lost the Mars Climate Orbiter in 1999! Notwithstanding, from frequent use I already knew the correct format but after 5-months absence couldn’t see the problem right in front of me, obvious though it was.

In the absence of ‘real’ astronomy I’ve been playing with simple camera-tripod imaging, with some rewarding results; it’s got me thinking about purchasing a smaller, simpler Vixen Polarie or equivalent tracking mount head – watch this space! The same morning after sorting out the aforementioned date format problem, I took the opportunity to take a look at the sun in the east before turning round to see a beautiful waning crescent Moon in the western sky – who needs the night sky?

Fly me to the Moon

Too good to miss and after the previous evening’s disaster, I managed to get a pleasing sequence of images tracking an aircraft flying past the Moon – this being a case of making the best of what you have: daytime, the Moon and frequent overflying planes from nearby Gatwick airport and further afield. Being approximately 42,000 further away from Earth the Moon only looks about 4-times larger than the aircraft.

Flight animation

Changing the perspective completely, I was fascinated by last month’s image of the Moon passing in front of Earth, thus also presenting a fabulous view of what we call the dark side of the Moon. The transit was taken from the Deep Space Climate Observatory orbiting at 930,000 miles from Earth, or nearly four times greater than the Moon.

16th July 2015: The so-called dark side of the Moon, seen from the Deep Space Sky Observatory, as it passes across Earth. From our perspective that day it was a New Moon.

16th July 2015: The so-called dark side of the Moon, seen from the Deep Space Climate Observatory, as it passes across Earth. From our perspective that day it was a New Moon.

Pink Floyd take note – surely this image needs to replace the iconic cover from their 1973 album – it’s all about changing perspective; apart from being a spectacular photograph the image demonstrates the other side of the Moon is anything but dark!

Pink Floyd’s 1973 album cover, now surely obsolete?

Earth’s Junkyard

August 19, 2015 by grahamrob in Earth, General Astronomy, Widefield Imaging and tagged Perseids, Satellites | Leave a comment

Only very recently the BBC Horizon programme covered the increasing problem of space junk that now orbits Earth forming a virtual cloud of debris posing a serious threat in general and, in particular, to future space activity: obsolete satellites, broken, damaged or even fragments from destroyed man-made objects. In addition to the ISS, communication and other satellites can often be seen passing overhead but in reality these only represent the tip of the iceberg.

Earth’s Junkyard
Computer-generated image of objects and debris currently being tracked orbiting Earth; it’s the stuff we can’t see or track that is most worrying!

Whilst visiting my daughter in Somerset at the weekend the night sky was clear and fantastically dark thanks to the New Moon and lack of light pollution when compared to Fairvale Observatory in Surrey. Having already tried to image the Perseids in the preceding week unsuccessfully, I thought I’d try again in these much better conditions using a basic DSLR on a tripod and an intervalometer.

Despite excellent seeing conditions, the air was cool’ish and therefore prone to quickly form dew on the camera lens after just 20 minutes or so. At the time it didn’t seem as though I had captured anything of interest, however, looking at the images subsequently on the computer, I was excited to find a bright flash appearing between two of the pictures pictures – what could this be, it seemed too short to be a Perseid? Whatever it is was had gone in the next image 5 seconds later. I discovered the anomaly whilst flicking from one picture to the next when suddenly a bright point stood out from the otherwise unchanging starry sky by blinking – a characteristic of something unusual taking place.

I posted a query on SGL and the overwhelming consensus has been that it is most likely to be a satellite or debris flare from the aforementioned space junk – either a spinning satellite or debris that briefly produced a reflection as it passed through the field of vision. Looking closely the bright spot does seem to be elongated from left to right, suggesting movement, though I am still perplexed why it has therefore not produced a more significant trace given the 30-second exposure being used – for a moment I even thought it might be a Super Nova!

Notwithstanding, it’s an interesting effect, though sadly seems to confirm the extent to which mankind has already made a mess of the space around our planet.

Image before the solar flare appears - red circle indicates the area of interest.

Image before the satellite flare appears – red circle indicates the area of interest.

Solar flare, indicated by the red arrow?

+ 5 seconds later a satellite / debris flare, indicated by the red arrow?

Notes: The pictures were taken at 10.37pm on 16^th August, looking north east, at about +70^o inclination using a Canon EOS 700D + 18-55 lens, at 18mm and f5.6. Both images are 30 secs exposure at ISO1,600 with an interval of 5-seconds. The area of interest is indicated with a red ring in the first image, with the white ‘object’ appearing in the following image shown by a red arrow.

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.

Looking Up

August 3, 2015 by grahamrob in Uncategorized, Widefield Imaging and tagged Cassiopeia, ISS, Ursa Minor | Leave a comment

Having been unable to set-up Fairvale Observatory since April, it has been frustrating with almost no hands-on astronomy taking place. However, last night the march of time and serendipity played their part; by chance I glanced out of the window and lo and behold saw the International Space Station (ISS), which was then scheduled to pass almost directly overhead again 90-minutes later at 11.17 p.m. Now six weeks past the Summer Equinox sunset is coming increasing earlier, currently 8.45pm and by the time the ISS would be back the night sky was almost at astronomical darkness. This would provide a favourable setting for viewing and imaging – furthermore, the sky was almost clear and the temperature a comfortable 18⁰C, far from the sub-zero conditions back in February.

I have just purchased a second-hand EFS 55 – 250mm Canon IS telephoto lens, so what else was there to do but get outside and get ready to image the ISS next time round, thereafter one thing led to another! Being a more mobile set-up I was able to venture further from the house than usual and thereby obtain images of some constellations and asterisms which I cannot usually achieve from the Observatory.

Though not as spectacular as the Planets and DSO images, I found the simple sky photographs satisfying to shoot and enjoyable to look at. The beguiling night environment, exciting subjects, improving darkness conditions and my increased mobility, suggests things are looking up – in more than one way.

ISS Western view: 6 minute transit from West to East at 850

ISS Western view: 6 minutes total transit time from West to East at 85 degrees elevation.

ISS Overhead view

ISS Eastern view

Summer Triangle – signature asterism of the summer night sky: clockwise from top left: Deneb – Vega – Altair.

The W-shaped asterism of the Cassiopeia straddles the Milky Way in the northern sky and is made of 5-stars: Segin, Ksora, Cih, Schedar and Caph. The constellation contains a number of star clusters, most notable being M52 and close to Ksora, M103.

Cassiopeia

Ursa Minor – Like the Plough in Ursa Major, Ursa Minor has a ‘dipper-like’ shape and they are therefore respectively known as the Big and Little Dippers. Ursa Minor’s main significance is the North or Pole Star, AKA Polaris. Situated very close to the Celestial Pole, alignment of the telescope mount with Polaris is essential to achieve accurate tracking; unfortunately Polaris is obscured from Fairvale Observatory but can be seen from the garden.

Ursa Minor – Polaris star indicated by red arrow, with the ‘dipper’ to the right.

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’s Playground

May 12, 2015 by grahamrob in Deep Sky Objects and tagged Coma Berenices, Galaxies, Leo, Virgo | 1 Comment

The night sky has been full of surprises for me this Spring, in particular the very extensive presence of galaxies. Their occurrence has been mostly associated with the constellations of Leo and Virgo but also less well known (to me) Coma Berenices, located between the two aforementioned constellations. Despite being the 42^nd constellation by size and relatively small with few bright stars, Coma Berenices is nonetheless something of a little gem and every bit as interesting as it’s more famous neighbours.

Previously part of the Leo Constellation, Coma Berenices was promoted to a constellation in the 16^th Century and named after Queen Berenice II of Egypt; the asterism was previously considered to be the tuft of hair at the end of the lion’s (Leo) tail, which has now become the ‘Queens Hair’. Though small, Coma Berenices contains eight Messier objects, several globular clusters and is rich in galaxies – including the northern part of the Virgo cluster – also with the North Galactic Pole located within its boundaries. All-in-all the constellation forms an impressive and interesting part of the sky at this time of the year.

Notable objects are: M53 (NGC 5024), M85 (NGC 4382), M88 (NGC 4501), M91 (NGC 4548), M98 (NGC 4192), M99 (NGC 4254), and M100 (NGC 4321). Whilst amongst the more famous features of the Coma Berenices is the Black Eye Galaxy (M64), the Needle Galaxy (NGC 4565) and the Coma Cluster of galaxies.

M64, AKA Black Eye Galaxy, Evil Eye Galaxy or the Sleeping Beauty Galaxy is the brightest in Coma Berenices and gets its name from the dark (black) dust band that obscures the stars in its bright core.

M64 Black Eye Galaxy
WO GT81 & Canon 550D (modded) + FF | 10 x 180 secs @ ISO 1,600 | 11th April 2015

NGC 4565 or the Needle Eye Galaxy is considered one of the finest examples of an edge-on galaxy, thus producing a slender, needle-like profile. Located 40 million light years away, almost directly above the North Galactic Pol, this giant barred spiral galaxy is about one third larger than the Milky Way and is more luminous that Andromeda.

NGC 4565 Needle Eye Galaxy
WO GT81 & Canon 550D (modded) + FF | 10 x 180 secs @ ISO 1,600 | 11th April 2015

Some 60 million light-years away, M88 is located in the lower area of Coma Berenices, is over 100,000 light years diameter and one of the brightest galaxies of the Virgo Cluster.

M88 with other galaxies of the Virgo Cluster nearby.
WO GT81 + Canon 550D (modded) + FF | 20 x 180 secs @ ISO 1,600 | 25th March 2015

Apart from a few occasional opportunities since obtaining my new equipment last Summer, I have been yearning for more galaxies to image and have thoroughly enjoyed Spring’s veritable playground of galaxies that have filled the sky in their hundreds and sometimes thousands since February. Notwithstanding, my 81mm refractor though good struggles to obtain the detail of these magnificent, mind-blowing Deep Sky Objects and I can only look forward to the day of owning a larger aperture telescope and have mastered the art of long-exposure tracking, which I am still working on. In the meantime, I now await the development of the Summer sky and another crack at objects first encountered last year.

All in a spin

April 23, 2015 by grahamrob in Deep Sky Objects and tagged Coma Berenices, DSO Imaging, Galaxies, Star Clusters, Virgo | 1 Comment

It is now just over six months since acquiring my new astronomy equipment and therefore the first time I have experienced imaging DSO objects of the Spring night sky. Following the passage of Leo, the main show has now well and truly arrived as the constellations of first Coma Berenices and then Virgo pass overhead, bringing with them a virtual fireworks type display of spectacular stellar features. To DSO fans Spring means one thing – galaxies – too many to comprehend, making it difficult to know where to start. In my case the detailed beauty of these galaxies will need to wait until I have a substantially larger telescope and can achieve much, much longer exposures. In the meantime I just marvel at the spectacle and have been trying to image some of the more iconic of these springtime beauties. Both constellations seem abound with galaxies but two groups are particularly exciting: the Coma Cluster and Virgo Cluster, within which there a large number of fine examples to choose from.

Just the tip of the iceberg: part of the Virgo Cluster that is crowded by galaxies.

Just the tip of the iceberg: part of the Virgo Cluster crowded with thousands of galaxies.

I was first drawn to Markarain’s Chain in the Virgo Cluster, a string of galaxies that form a gentle curve. Stretched over some x ly the chain includes two Messier Objects – M86 & M84, together with NGC 4438, NGC 4435, NGC 4461, NGC 4458, NGC 4473 & NGC 4477 amongst many others. In fact this entire part of the sky contains literally thousands of galaxies, of which Markarain’s Chain is just a small but interesting part.