Photons & Photography

December 20, 2016 by grahamrob in Deep Sky Objects, Equipment, General Astronomy, History, Imaging, Processing, Universe and tagged Einstein, Messier Objects, Photography, Science | 1 Comment

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I’ve been interested in photography from a young age. As I child I played with my parent’s Kodak box camera and, as far as I can remember, my first camera was a Kodak Brownie at the age of about nine. It’s a wonderful medium that I have now experienced for over 50-years, on land, underwater and now for astrophotography.

My cameras

I’d like to think I know a thing or two about photography by now; underwater photography and digital astrophotography have been particularly challenging in different ways but the latter is a real eye opener that has expanded my knowledge of digital imaging significantly. Capturing images of distant objects that can only be seen with the use of sophisticated equipment and complex processing also requires an in-depth understanding of light itself.

Basic working concept of digital sensors

Modern camera sensor

Having spent the first half of this year reading Einstein’s biography, I have recently started an online course at Stanford University on his ground-breaking Special Theory of Relativity. Einstein’s many insights into the physical world are profound, which more than 100-years on still challenge most of us to understand. Light was at the core of his famous 1905 paper, in particular it’s duality as a waveform and light quanta, or photons – defined as a quantum of electromagnetic radiation. His concept of the photoelectric effect has enabled the development of today’s digital camera sensors and CCDs. The core principal is the production of electrons as light shines onto a material, whereby the light (photon) knocks out an electron which can then be collected electronically – the basis of digital photography.

Camera obscura at Lacock

Camera obscura image

Lacock Abbey

In September I visited Lacock Abbey in Wiltshire, initially a 13^th century nunnery which is now run by the National Trust. Today it is better known as the home of William Henry Fox Talbot (1800 – 1877) – mathematician, astronomer and archaeologist but most famously the inventor and pioneer of photography, notably developing, fixing and printing. The window photograph below (left) was taken at Lacock Abbey in August 1835 and is recognised as being from the oldest ever camera negative produced by Fox Talbot, on the right is the same window in 2016.

First ever print, taken at Lacock Abbey 1835

The same picture by me September 2016

In the early 19^th century Thomas Wedgwood had made photograms – silhouettes of leaves and other objects – but these faded quickly. In 1827, Joseph Nicéphore de Niepce produced pictures on bitumen, and in January 1839, Louis Daguerre displayed his ‘Daguerreotypes’ – pictures on silver plates – to the French Academy of Sciences. Three weeks later, Fox Talbot reported his ‘art of photogenic drawing’ to the Royal Society, which subsequently became the de facto basis of modern film photography.

Fox Talbot’s desk in his study at Lacock Abbey

Fox Talbot lived and worked at the Abbey for most of his life. As well as an excellent museum, which details the history of photography and photographic processes, the house contains his rooms where he developed (no pun intended) the aforementioned inventions and is surely a ‘must do’ visit for any keen photographer. Like many at that time he was a polymath, with notable friends and accomplices who worked in similar and other scientific fields:

Sir John Herschel – astronomer, mathematician, botanist & chemist, Gold Medal winner and founder of the Royal Astronomical Society, son of William Herschel who discovered Uranus.

Charles Babbage – mathematician, philosopher, mechanical engineer, considered “the father of the computer”;

William Whewell – leading 19^th century scientist, recognised in the fields of architecture, mechanics, mineralogy, moral philosophy, astronomy, political economy, and the philosophy of science;

Sir Charles Wheatstone – physicist, inventor of stereoscopic photography, the telegraph & accordion;

Sir David Brewster – physicist specialising in optics, mathematician, astronomer & inventor of optical mineralogy and the kaleidoscope;

Peter Roget – physician, theologian, lexicographer and publisher of Roget’s Thesarus.

This particular group are now remembered by a table setting in the Abbey’s dining room, where they gathered for dinner; the mind boggles at the conversation!

Fox Talbot’s pioneering photography work preceded the early 20^th century understanding of light that arose from Einstein and its more recent application in semi-conductors as camera sensors, of which I am sure he would have approved. At that time the Universe outside of our galaxy was also unknown and he would have marvelled further at the thought of imaging other such distant galaxies such as M33 below; like photons, photography has come a long way since his death in 1877.

M33 Triangulum Galaxy – consisting of some 40-billion stars, the photons in this image have travelled 3-million light years to reach my camera’s sensor! | WO GT81 + modded Canon EOS 550D & FF guided | 18 x 300 secs @ ISO 800 & full calibration | 22nd October 2016

It’s All Relative

December 6, 2016 by grahamrob in Deep Sky Objects, General Astronomy, Imaging, Processing, Software, Universe and tagged DSO Imaging, Einstein, Monoceros, Orion, Perseus, Pleiades | 2 Comments

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I spent the first half of this year reading Walter Isaacson’s biography of Albert Einstein, which apart from providing a fascinating insight into the man and his work, whetted my appetite to understand better the science. Following previous success studying astronomy courses online, I set out to find a suitable programme to achieve this goal. As a result I enrolled for Understanding Einstein: the Special Theory of Relativity run by Professor Larry Lagerstrom of Stanford University, USA, which after two months I have just completed. spacetime

The course is a good mix of qualitative and quantitative information, which at times has been quite challenging but nonetheless proved very worthwhile. The lecturer is very clear and thorough, an essential quality when dealing with this difficult and often bewildering subject. Einstein’s paper On the Electrodynamics of Moving Bodies outlines the Special Theory and was just one of four published at about the same time in 1905 (“The Miracle Year”) which included: Brownian motion, Mass-energy equivalence (E=Mc²) and The Photoelectric Effect, the latter of which won him the Noble Prize. At the end I now feel I understand the basics of Einstein’s ground breaking science properly, which apart from being interesting provides valuable insight and understanding of the Universe and related issues of space and time.

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During this period I have also been thinking about how to improve my astrophotography and the way forwards. I’ll be on the learning curve for years to come and accept that there’s much I can still improve on using current equipment and processes but after more than 2-years astroimaging, mostly with a DSLR camera, I feel I have reached something of a crossroads and need to change tack in order to achieve more meaningful advances once again. Inevitably this is likely to mean new equipment and most likely a move to LRGB / Narrowband format. In the interim, whilst I consider the options, I have also been researching suitable capture / sequencing software, post-processing techniques and programmes. I am concerned that this will result in another level of complexity but I think it has to be done in order to progress – watch this space.

Continuing a trend that’s been apparent for the past year, clear nights have been something of a rarity since mid-September; this is a concern if I am to pursue astrophotography to the next level. However, high pressure was unusually dominant over Fairvale Observatory during the last days of November and cold, clear skies have provided good conditions for astronomy at last.

Getting better – PHD2 screen 30th November 2016: DEC is good but room for improvement with the RA settings. The impact on tracking and image quality is noticeable.

Whilst I have certainly not fully mastered guiding I am now routinely using PHD2. This in itself has probably been the major breakthrough this year, which with the aforementioned clear skies I wanted to take full advantage of. Hidden within PHD2 I have also discovered and am now starting to experiment with the on-screen drift align routine, with reasonable results; using the gamepad for mount control and a new wireless link with my tablet computer, I can also make focus and alignment adjustments at the mount without returning to the computer each time.

As a result I have dispersed with the SynScan handset for alignment and can now completely set-up and control imaging with the computer and tablet; this is nothing short of a revolution which I am hopeful will greatly increase set-up time as well as improving control and tracking accuracy – yipee! Even with average guiding results I am now achieving good exposures of 5-minutes or more and therefore decided to put this success to work and re-image some winter wonders over three, yes three, consecutive nights at the end of November.

Imaging targets between 28th & 30th of November 2016 – for descriptions & previous images taken of these objects click on the following list of names: (1) M45 Pleiades (2) Barnard 33 The Horsehead Nebula & NGC 2024 Flame Nebula (3) M42 Orion Nebula (4) NGC 2244 Rosette Nebula (5) NGC 1499 California Nebula (6) IC 405 Flaming Star Nebula

The night sky at this time of the year contains many of my favourite objects, but surprisingly I had not imaged some of the chosen targets for more than a year or two and it was both enjoyable and pleasing to reacquaint myself again. With a new perspective gained from this exercise, the progress I have made with equipment and techniques is more apparent. Notwithstanding, it’s time to move on – everything’s relative.

M45 Pleiades, Taurus constellation: 12 x 300 sec @ ISO 800 | 28th November 2016

NGC 2014 Flame Nebula & Barnard 33 Horsehead Nebula, Orion constellation: 15 x 300 sec @ ISO 800 | 28th November 2016

M42 Orion Nebula & M43 De Mairan’s Nebula, Orion constellation: 2 x 300 sec @ ISO 800 | 28th November 2016

NGC 2244 Rosette Nebula, Perseus arm of Milky Way, Monoceros region: 21 x 300 sec @ ISO 800 | 29th November 2016

California Nebula, Perseus constellation: 12 x 300 sec @ ISO 800 | 30th November 2016

IC 405 & 410 nebulae: 15 x 300 @ ISO 800 | 30th November 2016

Notes: all images taken using a William Optics GT81 refractor telescope + PHD2 guiding + modded Canon 550D DSLR & x0.80 field flattner @ ISO 800 with full darks + bias + flats calibration and processed in Deep Sky Stacker & Photoshop CS2

Two’s Company

November 10, 2016 by grahamrob in Deep Sky Objects, General Astronomy, Imaging and tagged Aquilae, Cygnus, Double Stars, Globular Clusters, Messier Objects, Pegasus, Saturn | Leave a comment

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The night sky is full of wonderful worlds, which themselves consist of amazing objects and features. I was originally drawn to astronomy by viewing Saturn through a telescope, which to this day retains a fascination and beauty for me. Of course it is Saturn’s rings that make it stand out as perhaps the iconic object of the night sky; even to the lay person their nature and colour tell us something special is taking place. The rings and associated shepherd moons indicate that something is happening to bring all the particles and objects precisely together in a disc that rotates around the planet – gravity. Perhaps surprisingly this force remains a mystery to science, although it is now clear that it has an overarching impact on the development of the Universe itself.

Another fascinating feature of gravity is the formation of globular clusters, which I find both beautiful and bewildering. Bound tightly by gravity, each cluster is made of at least several hundred thousand very old stars, typically between 8 to 10 billion years, which usually orbit at a far distance outside and at right angles to the galactic disc. So far about 158 globular clusters have been identified around the Milky Way and we now know such objects are also commonly associated with other galaxies. During the summer and autumn many of these enigmatic star clusters can be seen across the sky, which form wonderful imaging targets.

M15: 12bn light-years old globular star cluster | Constellation Pegasus, 33,600 ly from Earth, apparent mag. +6.2, size 18.0′ (diameter 176 ly) | WO GT81 + modded Canon 550D & FF | 10 x 300 sec @ ISO 800 & full calibration | 22nd October 2016

Although I have previously spent time observing and imaging Saturn and various globular clusters, as well as notable single stars such as Betelgeuse and Altair, for some reason I have neglected their binary relations. And so in early autumn this year I turned the telescope and camera towards two of the better examples of these double or binary stars. So-called Doubles consist of two stars orbiting around a barycentre, captured by each other’s gravity. The challenge is to ‘split’ the stars, thereby differentiating each star as individual features and if relevant by colour, either by observing though the telescope or in an image.

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My initial target was the beautiful Albireo (below), a double star consisting of the mag. +3.1 gold coloured Beta Cygni A and its mag. +5.1 bright blue partner Beta Cygni-B. At a distance of 430 light-years from Earth and separated by 35 arc seconds, the stars have an implied orbital period of at least 100,000 years. Together with Deneb, Sadr, Gienah and Delta Cygni, Albireo forms the Northern Cross asterism, which lies almost overhead at midnight during the late summer months in the Northern Hemisphere. Situated at the head of the Cygnus (Swan) constellation, Albireo is also known as the “beak star”. The contrasting colours of the two stars form one of the most beautiful doubles of the summer sky and forms an attractive imaging target.

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Located in the nearby constellation of Aquila but less notable than Albeiro, is the double 15 Aquilae (below). Some 4-billion years old and a hot 11,000^oC in temperature, the larger mag. +5.4 orange giant star is located some 190 light-years from Earth. Its smaller partner is a cooler white mag. +7.7 star, situated 38 arc seconds away but ‘only’ 4,400^oC hot. Such features abound in the Aquila constellation and I hope to return to this region of the sky again next year for more double fun!

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Doubles are a real treasure of the night sky that are surprisingly common but are easy to overlook. They are often interesting as well as beautiful to observe and image – I can’t think why it’s taken me so long to get round to them?

Overspill

October 27, 2016 by grahamrob in Deep Sky Objects, General Astronomy, Imaging, Solar system and tagged Andromeda, Aquila, Delphinus, Lyra, Messier Objects, Moon, Pegasus, Veil Nebula | 1 Comment

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After months of cloud followed by 3-months of lost imaging time due to a mysterious camera / mount control problem, I was on the verge of throwing in the towel by August. But then I sorted the problem, started guiding and as if by magic, with a prolonged spell of good weather managed 7-nights of astronomy between 23^rd August and 13^th September; such was the intensity I was able to work over consecutive nights and by the end quite exhausted but happy.

Under clear skies and warm nights I could operate in just shorts and a T-shirt, a hitherto unknown experience at Fairvale Observatory. In such comfort I was also able to experiment and optimize the equipment set-up further – oh, if it could only be like this always. Of course I did not miss the opportunity to chase some night sky objects as well, imaging 11 targets all-in-all, sometimes on more than one occasion. It was a glorious time which has since taken time to organise and process.

NGC 6905

NGC 6781

M57

M57

Top left – NGC 6905 Blue Flash Nebula in Delphinus constellation 42″ x 35″ mag +11 26th August; Bottom left – NGC 6781 planetary nebula in Aquila constellation 1.8′ +mag 11.8 23rd August; Middle M57 Ring Nebula Lyra constellation 1.4′ x 1.1′ mag +8.8 13th September; Right M57 23rd August

A number of these images have already been reviewed in Forbidden Fruit and The future is not what it used to be but, such was productivity that for the record I’ve collected the overspill here. Inevitably targets reflected what was about and in sight from this location at the time but were nonetheless diverse in nature, ranging from the Witch’s Broom to planetary nebulae, the Andromeda galaxy and, making use of the otherwise frustrating monthly occurrence, the Moon. Features such as M57 and NGC 6781 are intrinsically too small for the William Optics GT81 and Canon 550D, filling significantly less than 1% of the original image but after cropping both are evident in the final picture.

M15

NGC 6960

M31

Top Left – M15 Globular cluster Pegasus constellation 29th August; Top Right – Q1 Moon 23rd August; Middle Right – NGC 6960 Witch’s Broom Western Veil Nebula; Bottom – M31 Andromeda Galaxy 26th August

These images are not particularly memorable but it was a fun time and I will remember the enjoyable experience for a long while. Of course, the cloud has now returned and since passing the autumn equinox night temperatures have plunged into single figures. On the plus side, Orion is on its way together with all the other photogenic objects that characterize the winter night sky – can’t wait!

The future is not what it used to be

October 7, 2016 by grahamrob in Autoguiding, Deep Sky Objects, General Astronomy, Imaging, Processing, Software and tagged Andromeda, Photography, Veil Nebula | 3 Comments

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If I’m honest my astrophotography has so far often been – never mind the quality feel the width! That is to say, I have tended to chase objects – nebulae, galaxies, planets, solar – in order to learn about my equipment and the night sky as well as just have fun recording images of these distant worlds. Nothing wrong with that is there? It’s not that I don’t aspire to obtaining the best image possible and I have made good progress since starting out but I’ve often felt constrained by circumstances.

Although I’ve generally been happy with my images, it’s a fact that there are a number of factors that altogether make astrophotography difficult, especially here at Fairvale Observatory:

Poor weather & persistent cloud cover
The Moon
Buildings & trees obscure sightlines
Light pollution from Gatwick airport
Numerous aircraft passing overhead
Equipment problems
Software problems
Equipment and software failures
Equipment limitations
Need to assemble equipment each time

Bad weather, frequent cloud cover, limited sightlines, aircraft trails and the inevitable monthly occurrence of the Moon limit imaging opportunities here.

Under these circumstances I usually need to grab what I can, frankly it’s a miracle I’m able to achieve anything sometimes; Met office statistics for the six-months period from September 2105 showed cloud cover was a record 68% compared with an historical average of 32% for that time of year, as a result it was unusual to be able to undertake astrophotography more than once month, if that! Wherever possible I therefore have to target those items that I can improve easily, quickly and cheaply dealt with, which is mostly equipment. Buoyed by renewed enthusiasm from my recent autoguiding success, I now intend to concentrate on changing some key items that I hope will eventually bring about more noticeable improvements.

sign2 For a while I have been thinking about getting a larger telescope, in order to get to those faint fuzzies that are beyond the capabilities of the otherwise excellent William Optics GT81. As usual the choice is a minefield of possibilities, each with inevitable imaging pros and cons! I started thinking about a Ritchey Chrétien or Schmidt Cassegrain but I have really appreciated the qualities of the aforementioned WO GT81 and am now erring towards a larger refractor. However, after further consideration I am now considering a change of priorities.

In September I was fortunate to attend a presentation on image processing by Nik Szymanek who, it has to be said, really knows his onions when it comes to astrophotography; I was intrigued and impressed to find out he also hails from my neck of the woods when I was a teenager in Essex and is an accomplished rock drummer – something I also used to meddle with in the past – what a geezer, as he would say. The talk was very instructive and I am now ploughing my way through Nik’s fabulous book on the subject called Shooting Stars (published in magazine form by Astronomy Now). Such personal, first-hand and relevant guidance is difficult to find in astroimaging and the book has a wealth of really practical information and useful advice that I wished I’d known sooner. Good equipment is important but in the world of digital imaging the significance of processing cannot be overstated. It’s a dark art alright (no pun intended) but Nik’s work has strengthened my resolve to improve my processing knowledge and I’m even more determined to raise the bar during the forthcoming winter.

20160708-shooting-stars-for-store Following Nik’s talk and listening to others, the penny that has now dropped is that for the moment it’s not the telescope but the camera that needs changing. After careful thought it’s apparent that I already have very good set-up, yes a bigger aperture would be good for those smaller fuzzies but the 81mm apochromatic refractor I already own is an outstanding telescope that still has much potential when combined with the AZ-EQ6 mount and now autoguiding.

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The addition of a modded DSLR at the beginning of last year had a significant impact on my images, especially with Ha dominant DSOs which I literally saw in a new light using this camera. I have continued with the DSLR for a number of reasons but mainly because I am familiar with such cameras which are relatively easy to use and produce reasonable results when starting out with astrophotography. However, listening to Nik and reading the forums and elsewhere, I have come to accept that the best way forwards should now be a CCD-type camera. As a result I am deep in my research of CCD issues and possible cameras – this could take some time and won’t be cheap!

The operation of CCDs is quite different to a DSLR and I’m sure will involve a whole new period of pain but it’s clear that this is the best route for now if I am to significantly improve my astrophotography. Other than the technical challenges CCD imaging presents, I am however concerned about the greater number of frames needed for LRGB + calibration and how that’s going to work with the weather restrictions and other problems I have but it’s got to be worth a try.

However, before setting out on this daunting task I first slewed the camera towards a few familiar objects just to experiment with guiding and assess the benefits it might bring to my imaging in the interim. A spell of unusually good weather in late August – early September was too good to miss and with guiding I was able to achieve exposures of up to 8 minutes. However, for the moment I continued to limit the number of Subs and calibration frames just to ensure I could shoot more objects in the available time, plus you never know when the next bank of cloud will roll in – old habits die hard!

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Looking at the results below demonstrates my progress when compared with earlier images but the limited number of frames and calibration has probably restricted the full benefit of what might be gained from guiding and some shots remains quite noisy. Nonetheless, I now have high hopes that the potential is within my grasp to make real progress in achieving better image quality. I am not convinced I have yet reached a turning point but I am well positioned to navigate the tasks required to get there, which are now more clearly understood and in my sights or should that be RDF – watch this space!

M31 Andromeda Galaxy

WO GT81 + unmodded Canon 700D & FF| 10 x 30 secs & ISO 800 | August 2014

WO GT 81 + modded Canon 550D + FF | 9 x 120 secs @ ISO 1,600 | 19th September 2015

WO GT81 + modded Canon 550D & FF & PHD guiding | 10 x 300 secs @ ISO 1,600 calibration | 8th September 2016

NGC 6905 Western Veil Nebula – The Witch’s Broom

NGC 6960multiplelevelsonecontrast FINAL(Medium)

Canon 700D | 20×90 sec + darks.bias/ flats @ ISO 800

WO GT81 + modded Canon 550D + FF & PHD guiding | 5 x 300 secs @ ISO 1,600 & calibration | 8th September 2016

NGC 6888 Crescent Nebula

WO GT81 + modded Canon 550D + FF | 19th October 2015

WO GT81 modded Canon 550D + FF & guiding | 10 x 300 secs @ ISO 1,600 & calibration | 11th September 2016

NGC 6992 Eastern Veil & Bat Nebula

Eastern Veil Nebula – NGC 6992 (right) & NGC 6995 (left). WO GT81 + Canon 700D & FF | 29 x 120 secs + darks/bias?flats @ ISO 1,600

Eastern Veil Nebula (NGC 6922 & 6995): WO GT81 & modded Canon 550D + FF & guiding | 10 x 300 sec @ ISO 1,600 + darks | 11th September 2016

Forbidden Fruit

September 21, 2016 by grahamrob in Autoguiding, Deep Sky Objects, General Astronomy, Imaging, Software and tagged DSO Imaging, Guiding, Messier Objects, Nebulae, Photography | 3 Comments

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Soon after embarking on my astrophotography adventure just over two years ago it became apparent that after getting the basics right – polar & star alignment, focus, image capture etc. – the Holy Grail of imaging is increased exposures times, thereby collecting more of those elusive photons that have travelled across the Universe. The first step to achieving this goal is tracking, which since purchasing my AZ-EQ6 mount in 2015 I have been successfully improving over time, on a good day achieving 180-second exposures and from time-to-time resulting in some decent images. However, the light from DSOs is often very feint and can require much longer times, which is easier said than done.

At the same time as acquiring the aforesaid mount and a William Optics GT81 telescope I also purchased a William Optics 50mm guide scope, with which I intended to start guiding and thus push exposures above my 3-minute barrier. Despite these aspirations, through a combination of events and my unease about the apparent difficulty of guiding, the guide scope has remained unused – until now. Having recently purchased a dedicated Starlight Express Lodestar X2 guide camera, I have finally been emboldened enough to give it a try.

Starlight Express Lodestar x2 Guide Camera can be used either via the mount’s ST4 port or via ASCOM and the computer for pulse guiding.

I initially struggled to set up the guide scope and get the guide camera working together. In particular obtaining focus proved very difficult; like the GT81 the guide scope focus turns out to be achieved within a very short distance that is measured in fractions of millimetres, which in this case required the insertion of an extension tube.

Reminiscent of the Space Shuttle on its Boeing 747 transport plane! The William Optics 50mm guide scope + Lodestar X2 guide camera neatly mounted atop the GT81 imaging scope using the integral rings.

Thereafter the big challenge, which I had previously avoided, was to start using the very popular PDH guiding software; Push Here Dummy (PHD) is named tongue-in-cheek by its original creator Craig Stark and is an amazing but somewhat intimidating piece of software.

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The principle is simple – find a star within the FOV and use it as a fixed reference point from which to assess and then correct small tracking errors in order to achieve better tracking, which thereby maintains pinpoint accuracy and enables longer exposure times, thus avoiding trailing of the sky and the objects being imaged. Its use is regarded as something of a dark art but I have finally grasped the nettle with some success. After months of clouded skies followed by an almost fatal equipment failure (see here for more), a period of exceptionally good weather and clear skies since late August provided the ideal opportunity to get to grips with this challenge that has so far eluded me.

At first I used a couple of sessions to overcome some past problems and ensure that everything was stable and worked well for basic tracking and imaging, in particular:

Repair and improve the imaging camera’s AC/DC adapter lead;

Where possible improve all other leads and connections – once bitten …..! In this respect I have significantly re-arranged and tidied up the many power, control and camera leads, which has included the addition of right-angle USB / mini-USB camera connectors that now makes plugging-in easier and produces less strain on the connections i.e. more secure. Simple, cheap and something I should have undertaken long ago;

Revisit EQMOD-ASCOM in order to achieve more robust tracking – especially reviewing the star alignment procedures;

Fit the guide scope using the rings incorporated onto the GT81 OTA, subsequently re-balancing the equipment and improve the mount’s feet positioning.

At this point I spent a couple of nights just playing with the equipment and in particular EQMOD-ASCOM, so as to obtain the best possible alignment; having suffered an enforced absence from imaging I just wanted to have some fun again too. At the end of this process, first using SynScan for polar alignment before switching to EQMOD-ASCOM + Cartes du Ciel for star alignment, I successfully produced a good 10-star alignment model which was then saved for future use. The resulting images already showed some improvement but I still had to tackle PHD. With unusually good weather I decided to leave the final set-up outside under cover, thus preserving the settings for a shot at the aforementioned task of guiding next time. In the interim I then needed to read the operating instructions and watch numerous videos on the use of PHD.

EQMOD-ASCOM 10-point alignment model. With an obstructed view of the northern sky by my house, all points are inevitably located in the southern quadrants.

Like so much of amateur astronomy, I will forever be grateful for the time and effort given by others to help those like me pursue our hobby. The material, videos and responses to my forum queries on guiding have as usual been nothing short of outstanding and very, very helpful. It’s still been difficult to get going but without the help and support of others it would be a complete non-starter. In this respect I’d like to pay credit to SGL and the Open PHD Guiding forums.

Armed with this knowledge I have since undertaken a few sessions using PHD2 with reasonable success, achieving exposure times of 5-minutes and more. Changing conditions and different objects make it necessary to continually finesse guide settings throughout the night and between nights and it’s already obvious that there’s much more to learn. Such adjustments are not always linear or empirical in nature and will often only come from gut feel (experience).

I have chosen to use ASCOM pulse guiding, though my equipment also has ST4-ports which I had initially intended to use due to its apparent simplicity. I am unable to argue the pros and cons of each method but there seems to be an overwhelming preference for pulse. What I do understand (I think) are the greater subtleties that can be obtained with the pulse guiding technique and in particular, the co-ordination it provides with ASCOM, thereby ensuring PHD and the mount communicate with each other to provide essential directional information as well as guiding. I am still investigating the impact of various BRAIN settings but through trial-and-error have progressed since my first guiding session.

First Pass: early guiding results 30th August 2016

Getting better: most recent guiding results 12th September 2016

Calibration of PHD is frustratingly slow and it seems that even after successfully completing the RA-procedure can still fail during the subsequent DEC / backlash clearance. After calibration use of the PHD Guide Assistant can then provide more help in achieving the best settings for the given set-up and conditions, though it is also very slow. However, once completed PHD is fantastic and so far has run well during the night, even when changing objects. Furthermore, I’ve also studied and experimented with the PHD Drift Align tool and am hopeful that by using this I may soon be able to both dispense with SynScan altogether and improve polar alignment, hitherto my imagining nemesis as I cannot see Polaris from my location – a very exciting prospect – what’s not to like?

Starting a sequence of experimentation I chose a familiar but hitherto difficult DSO object to image that should benefit from longer exposures. Having by now reached late-summer / early autumn, there were a few old favourites around such as the Veil and North America nebulae but for these trials I decided to go for the low hanging fruit of M27 or Apple Core nebula AKA Dumbbell nebula.

My previous image of M27 in August 2014!

With limited success I imaged this planetary nebula in my early days of astrophotography but with its 8.0’ x 5.6’ size and apparent magnitude of +7.5, I found it difficult to obtain good detail and colour. However, even without guiding the improved set-up and alignment produced better results at 3-minutes and with +5-minute guided exposures the images immediately showed very noticeable improvement.

The images were taken on four different nights starting on 23rd August and finished on 8th September, during which time the sky was clear and the weather warm with very low humidity, though by the end seeing conditions had started to deteriorate due to the impact of the emerging 1st quarter Moon. All images have been cropped to the same size of 700 x 500 pixels or 2% of the original FOV i.e. an object size of about 0.20%! Given this very small size M27 really is at the limit of the GT81 telescope.

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Strictly speaking the images are not fully comparable as the aggregate exposure times are not equal but nonetheless I think the results demonstrate the positive impact of guiding. The final two images are guided but do show greater star distortion, particularly at 8-minutes. I suspect this may be due to the period over which the mount was left outside and would probably have benefited from some alignment tweaking before imaging re-commenced – lesson learned; the severe cropping ratio has also magnified any problems that would probably be less obvious in a larger widefield image. There’s obviously room for improvement but I’m very happy with these early results which I can hopefully now build on.

M27 Apple Core Nebula – my first and favourite guided image | William Optics GT81 + 50mm guide scope & 10-point EQMOD-ASCOM star alignment model | modded Canon 550D + field flattener & Starlight Express Lodestar X2 guide camera | 3 x 300 secs @ ISO 1,600 & full calibration, 3.3% cropped image| 30th August 2016

Unfortunately there is some downside to the longer exposures obtained from Fairvale Observatory: potentially more aircraft tracks and cloud plus more extended imaging time is unavoidable but overall it is, as expected, a major leap forwards for my astrophotography. There’s still much to learn and improve with the technique but for now I am delighted to say that after nearly two years I am at last successfully guiding – would you Adam & Eve it?

Summertime Blues

June 15, 2016 by grahamrob in Deep Sky Objects, General Astronomy, Imaging, Software and tagged DSO Imaging, Jupiter, Mars, Saturn, Star Clusters, Sun | Leave a comment

This year the Summer Solstice falls on 20th June at 23.34 BST, meaning the Sun will have reached its furthest point north; as a result from 22nd of May to 19th July 2014 there is a state of permanent Astronomical Twilight AKA Nautical Darkness at Fairvale Observatory. This means there is a complete lack of Astronomical Darkness for imaging, which when combined with short nights poses various problems for astronomy in general. Notwithstanding, there are benefits and other opportunities which are worth exploiting.

Annual darkness at Fairvale Observatory 2016

To turn the problem around an obvious solution at this time is viewing and imaging the Sun. However, following the initial success of testing my equipment in preparation for Mercury’s transit of the Sun on 9^th May, the actual event proved disastrous for solar imaging. I have subsequently re-checked the equipment and software set-up and the problem has continued but without any obvious reason. Popular opinion on the EQMOD Forum is that it is a software issue – drivers, EQMOD, EOS Utilities – so when time allows over the summer I will reinstall and test everything, hopefully ready for the return of astronomical darkness on 20^th July. Murphy’s Law will likely mean it’s something else but for the moment this seems to be the only way forwards, or is it backwards? Having just managed to get guiding to work, I had been looking forwards to a new imaging era but that’s astrophotography!

Although the nights are now short the temperatures have been pleasantly warm; after the long dark but cold nights of winter (and spring this year) it’s been a real pleasure to be outside in summer clothing and without the threat of condensation on the equipment. Notwithstanding, ever present cloud and inevitably the Moon has continued to thwart my efforts until recently, as I have at last just managed a couple of very enjoyable evenings.

At the moment the three major planets of Jupiter, Mars and Saturn can all be seen at various times between 10.00 pm to nearly 3.00 am, when the early morning light then becomes evident. After putting on a great show during May, Jupiter still remains high in the sky just after sunset. Mars and Saturn are at a much lower declination of between 10^oand 17^o but provide very good views in the right seeing conditions, especially Mars which with an apparent dimension of 18.6^ohas recently looked excellent, even to the naked eye.

With such opportunities I decided to try out the Skywatcher 150PL and the ZWO ASI120MC once again. It is almost two years since I used this telescope, preferring instead the superior William Optics GT81 for viewing and imaging. However, with a focal length of 1,200mm and 150mm aperture (f8) the Newtonian scope is better suited to planetary objects; this was also the first time I rigged the scope for use on the AZ-EQ6 GT mount, thus providing better control than the EQ3-2 I have previously used.

Sure enough the views of each planet were very good but also being unaccustomed to the ZWO webcam through lack of use, I failed to obtain any images! Pity but the lesson learned is that I cannot just dabble with this equipment and need to dedicate more time in the future if I am to learn how to use properly again. Nonetheless, it was fun re-acquainting myself with these planets. As an unexpected bonus the ISS also flew right over Fairvale Observatory for over 7 minutes. This time the station was noticeably brighter than previously observed, which I put down to Nautical Darkness and the relative position of the Sun that results, thus producing greater reflection and therefore better illumination of the ISS when viewed from the ground?

All-in-all after months of difficulties and inactivity it was a good night and at midnight I therefore decided to swap to the William Optics GT81 for some DSO imaging. After setting-up the scope I looked up and, as if from nowhere, broken cloud had rolled in obscuring much of the sky and putting an end to any DSO imaging. Oh well, I had had a good time before and was at least able to get to bed at a civilised time – one of the other drawbacks of summer astronomy. As luck would have it the weather was also good on the following night, probably even better than before and this time I concentrated on bagging some DSO images as the planets again marched across the sky from east to west.

As a result of the aforementioned equipment and software problems I have resorted to the trusty SynScan handset again for alignment and mount control. Impressive though EQMOD and all the other paraphernalia are, so far I have found it all to be somewhat fickle and from my personal experience often unreliable. However, after last year’s enforced astronomy hiatus following my operation and the almost farcical lack of observing conditions over winter and now spring, I’ve become a little rusty with the set-up and as a result, on this occasion encountered my old nemesis – polar alignment – to be something of a problem once again.

Amongst the types of DSO objects, I find globular star clusters to be particularly intriguing; I had not even heard of such features until taking up astronomy in 2013. Some 158 of these ancient star clusters are known to orbit around the main disc of the Milky Way. At about 11bn to 13bn years old they are very old and despite what so-called experts might say, it seems to me their origin remains something of a mystery; it’s interesting that such clusters are also associated with other galaxies.

At this time of the year a number of globular and open clusters feature across the night sky and form excellent imaging targets. First up at about 11.00pm was M5 and immediately I discovered the shortcomings of my polar alignment, further aggravated by the decision to try 4.00 minute exposures = big mistake; ironically prior test shots turned about better!

M5 globular cluster + excess trailing! WO GT81 Canon 700D + FF | 9 x 240 secs @ ISO 800 + darks | 6th June 2016

M5 test shot: 10 sec @ ISO 6,400

M5 test shot: 15 sec @ ISO 6,400

Following on from M5 shortly after midnight, M13 appears at a much higher altitude, thus helping to reduce the impact of star trails. Furthermore, as I was by now fully aware of the polar alignment error, I reduced the exposure time from 4.00 to 2.00 minutes; it helped but nonetheless could not hide the impact on the resulting images. Note to self: always ensure good polar alignment. An EQMOD – ASCOM – CdC alignment model would be much better but until I can correct the aforesaid problem it’s down to SynScan and hopefully in the interim I can return to globular clusters once more during summer.

M13 with less but still noticeable trails! | WO GT81 & Canon 700D + FF | 19 x 120 secs @ ISO 800 + darks | 7th June 2016

Before going to bed I couldn’t resist a few quick shots of an old summer favourite, M57 or the Ring Nebula, itself also very high above Fairvale Observatory by this time of night. Considering the alignment problems the image wasn’t too bad, however, the first half of 2016 has really been a case of one step forwards, two back. I hope the next 6-months will be more positive, they will inevitably be darker and colder.

M57 Ring Nebula (left of centre) + Sulafat (left) & Sheliak (right) | WO GT81 & Canon 700D + FF | 13 x 120 secs @ ISO 800 | 7th June 2016

M57 – Ring Nebula, cropped.

Talk The Talk

May 25, 2016 by grahamrob in Equipment, General Astronomy, Imaging, Software, Widefield Imaging and tagged DSO Imaging, Moon, Nebulae, Photography | Leave a comment

“He who can, does. He who cannot, teaches.” 1903, George Bernard Shaw

At the end of last year I was contacted by a member of the Aperture Club, a photography group based in Purely – Surrey, who had come across this website and asked if I could give a presentation to the club’s members on astrophotography. Ordinarily I might have rejected the request – after all what do I know about astrophotography after only 18-months – but then again why not? Once I sat down and compiled some initial thoughts it was surprising just how far I had come and learnt already, albeit with still a long way to go. In the end I agreed and decided to take a two-fold approach to the talk: (i) a basic overview of astrophotography, and (ii) in this context my personal journey so far.

TTT Cover

The final structure adopted was like this, which I hoped would be both technically and aesthetically engaging and provide some insight into the challenges for astrophotography when compared to their day-to-day terrestrial pursuits:

Types of astrophotography
Astrophotography Methods
Light
Telescopes
Imaging
Cameras
Image Capture
Processing
Post Processing

I gave my talk to the club at the end of March, which lasted about 1-hour and I believe was well received; there was a good turn-out and subsequent Q&A session – which is always a good sign. I had also been asked to compile some related tasks for the members to undertake afterwards and after a break presented a second, shorter talk on some possible assignments. Copies of the talks can be accessed via the links here:

Astro Lecture PDF

Astro Assignments PDF

I would not be so arrogant to undertake such a presentation to other astrophotographers, at least not yet, but enjoyed introducing members of the Aperture Club to my hobby. Furthermore, through compiling the presentations I benefited from the process, which required me to think and understand the subjects more thoroughly than I might otherwise have done, making me think that Shaw was wrong. Good teaching requires a good understanding of the subject, the skill to impart that knowledge to the audience and the ability to apply the knowledge. I’ve previously walked the walk and in this instance I’d like to think I was able to talk the talk – I found the experience rewarding and I hope members of The Aperture Club did too?

Transit

May 9, 2016 by grahamrob in General Astronomy, Solar system, Viewing and tagged Mercury, Sun | Leave a comment

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Unfortunately not my image: Mercury starting its transit across the Sun today, photo by NASA.

The transit of Mercury across the face of the Sun takes place about thirteen times each century and today was one of those occasions; the next is on 11^th November 2019. With months of bad weather I’ve been unable to undertake very little astronomy for some time but albeit late, spring actually arrived last week and I took the opportunity to shake-down my equipment and experiment with settings for solar imaging in the hope of capturing Mercury’s transit. Using a Baader solar filter and both the William Optics GT 81 and Skywatcher 150PL, I have successfully imaged the Sun before. Of course, inevitably I aspire to a dedicated Lunt or Coronado solar telescope one day in order to image details of the chromosphere and prominences, which are not visible using a white-light solar filter.

Sun spot activity is limited at the moment but the Baader filter and WO GT81 do a reasonable job, although I find achieving focus of the Sun quite difficult. Using the DSLR I experimented with the field flattener and an alternative basic 1/ 1.25” nosepiece, which produced a preferable result of a slightly larger and sharper image. I also tried the ZWO ASI 120MC webcam but as I don’t use this very often struggled to get the settings right for any sort of image – I’ll experiment more with that over the summer. I also put EQMOD-ASCOM and the newly acquired gamepad control through their paces which both worked well, so I was ready for the transit – weather permitting.

Last week’s test image of the Sun, with sun spot top left: WO GT81 + 1.25″ nosepiece | 1 / 2,500 sec @ ISO 100

After days of sunshine, albeit with high cloud that has continued to prohibit astrophotography at night, I was nonetheless hopeful of seeing at least some of the transit today. Notwithstanding, Sods law arrived in the form of a belt of cloud over south east England last night! Not to be defeated I watched the sky and cloud forecasts which suggested a glimpse of the transit might still be possible.

In hopeful anticipation I set up the equipment just before contact at 12.12 pm BST and shortly afterwards obtained a good view of Mercury as it started its transit across the face of the Sun. For the next three hours I managed glimpses of the planet as it continued its journey. It is very, very small but forms a distinct, sharp black dot against the background of the Sun when compared to the more diffuse, grey nature of the sunspots. It was an exciting experience and despite the drawbacks – cloud has now completely covered the sky for the rest of the transit – it was very enjoyable; so what’s the problem?

Despite all my preparation for imaging everything that could go wrong did and I was unable to obtain even a single photograph:

On setting up the camera and starting to focus the EQMOD-ASCOM tracking stopped and Carte du Ciel froze. Despite re-starting the set-up numerous times the tracking would not work!

Finally after resorting to the Synscan handset for tracking control, for some completely inexplicable reason I could not get any sort of image on the camera, that otherwise was working OK!

As I have learned many times before, the art of astronomy is patience and persistence but I am very disappointed not to have imaged Mercury during its transit today. Ironically once the cloud put an end to further activity, I tested the EQMOD-ASCOM tracking once again and it worked fine. Perplexed does not describe my feelings – oh well, 3-years to prepare for the next transit!

How I felt after today’s imaging!!! The transit view was still very good and I’m grateful for the breaks in the cloud.

The Sky’s The Limit

April 22, 2016 by grahamrob in Astronomy holidays, General Astronomy, Imaging, Widefield Imaging and tagged Arizona, Moon, Orion, Photography, Utah | 2 Comments

IMG_6235 (Large)

Imaging the Milky Way is a popular objective that has so far eluded me, mainly as I suffer from bad light pollution here at Fairvale Observatory. Embarking on a trip to the Southwestern USA recently where dark skies abound, I therefore had high hopes of at last achieving this goal but alas it was not to be and will have to wait for another day.

The trip of a lifetime

As a geologist I have often visited parts of Nevada, Colorado, Utah and California but never the famous sites of the Grand Canyon, Monument Valley, Glen Canyon (Lake Powell), Bryce Canyon and Zion National Park, which this time formed the trip of a lifetime.

Alvan Clark & Sons 24″ refractor telescope at Lowell Observatory, Flagstaff, Arizona

First stop was after flying into Las Vegas was Flagstaff, home of the Lowell Observatory, where Pluto was first discovered and amongst others houses a magnificent 24-inch Alvan Clark & Sons refractor telescope built in 1895, which I hoped to use for viewing at the observatory’s nightly public sessions. Unfortunately this was not to be as the sky remained resolutely overcast throughout the evening, despite good conditions earlier in the day. Notwithstanding, the observatory is a fascinating place and still remains an important centre of modern astronomy studies; the adjacent town of Flagstaff is also home to the Department of Physics and Astronomy at the Northern Arizona University.

Final notes and paper published by Percival Lowell postulating the existence of a Planet X beyond Neptune, later confirmed by Clyde Tombaugh at Lowell Observatory in 1930 and named Pluto

About 40-miles east of Flagstaff is the site of Meteor Crater, the best preserved meteorite impact crater on Earth. Nearly one mile in diameter and over 500 feet deep, the 50,000 year old crater is very big and very impressive. There’s a lot to like about Flagstaff if you’re into astronomy!

Meteor Crater, Arizona, USA

The Holsinger Meteorite: the largest remaining fragment of the 45 metre meteorite that created Meteor Crater

Moving on to the next stop at the Grand Canyon did not disappoint but staying just outside the park the location suffered some light pollution, compounded by cloud during the evening, thus prohibiting any imaging.

The incomparable Grand Canyon by day. Whilst we stayed around for sunset, unfortunately light pollution and cloud later prevented further nightscape imaging.

As a more remote location I had always envisaged that next stop at Monument Valley would be my first real opportunity to undertake some night imaging, for which purpose I had taken along the Vixen Polarie and a tripod. In preparation I had previously studied the sky in this part of the world using Cartes du Ciel, which indicated that the Milky Way would be well positioned during my visit; being 35^o latitude and 5,000 miles west of Fairvale Observatory meant that the sky was similar to that viewed in the UK three months ago and therefore included my favourite constellation Orion. Unfortunately I had overlooked one problem and my long-time nemesis, the moon.

The night sky from Lowell Observatory on 30th March 2016 – no Moon.

10-days later: night sky from Lowell Observatory on 10th April 2016, now with the Moon!

I was in the USA from 5^th to 17^th April but for some reason had modelled the sky in Flagstaff on 30^th March. It turned out that between then and 10^th April, when I was in Monument Valley, the by now half-moon had moved into the night sky and ruled out any chance of seeing or imaging the Milky Way. Of course, even if I had correctly identified the problem beforehand there was nothing I could do about it but it was still frustrating. Notwithstanding, it was a clear sky and not to be defeated turned to Plan-B, which instead took advantage of the moon’s position and in my opinion turned out quite well.

Monument Valley by Day: left to right – West Mitten, East Mitten & Merrick Buttes

Despite the remote location at Monument Valley there was noticeable light pollution from the hotel and ancillary facilities. However, being on the ground floor it was possible to set-up adjacent to the room’s balcony looking east, which was fortunately in the building’s own shadow, thus enabling a sequence of images to be taken of the night sky set against the buttes that typify this region. UnfortunateIy I overlooked setting the Vixen Polarie to half-sidereal tracking speed, which subsequently resulted in a blurred landscape when stacked but the original subs capture the buttes in some detail, themselves illuminated by the moon’s light = result!

Monument Valley by Night; order of buttes same as above. Canon 700D + Sigma 10mm wide-angle lens | 15secs @ ISO 6,400 | 10th April 2016

Monument Valley at Night – mulitple stacked shots: Sidereal tracking results in better sky but blurred landscape. Canon 700D & 10mm Sigma wide-angle lens | 20 x 15 secs @ ISO 6,400

Three days later I was in Bryce Canyon, the location of extraordinary geological features called hoodoos, which are the result of unusual and extreme weathering of the limestone cliffs found there. The land forms consist of thousands of various sized pillars of white and red limestone, seemingly lined up like soldiers along miles of the east facing limestone cliff face. Once again I used the moon to illuminate and capture the scene, this time using half-sidereal tracking. The result is somewhat haunting in nature but shows almost as much detail into the far distance as during daytime; I still find it incredible how sensitive the camera’s sensor is in gathering available light at night when extending exposure times and / or turning up the ISO setting.

Bryce Canyon at Sunset Point by Day

Bryce Canyon at Sunset Point by Night: Canon 700D + Sigma 10mm Wide-angle lens | 15 secs @ ISO 3,200 | 13th April 2016

It is clear I have much to learn about the deceptively simple nightscape photography using the Vixen Polarie but it is equally clear that the equipment provides significant potential and I look forwards to catching the Milky Way one day when the sky is clear and the moon absent. Notwithstanding the disappointment of missing out on the Milky Way this time, in the spectacular big country of Southwestern USA the sky’s the limit and I hope to go back again one day.