astro-imaging

The Perseids pack a punch thanks to clear skies

The skies were mostly clear in southern England for the peak of the Perseid meteor shower last night. Here are a few pictures that I captured of the display from the countryside to the east of Bristol.

Perseid fireball_12-13 08 2013webA brilliant Perseid fireball streaks across the sky. Credit: Will Gater

fireball_animation_smallThe same fireball image as above animated together with the previous and following frame to show the presence of a ‘persistent train’. Credit: Will Gater

Perseid 12-13 08 2013webA faint Perseid (top right), the Andromeda Galaxy and Double Cluster. Credit: Will Gater

Perseid fireball_dew_12-13 08 2013webA spectacular Perseid fireball captured with a lens covered in dew! Credit: Will Gater

Perseid_12-13 08 2013_croppedA Perseid meteor falls through the constellations of Pegasus & Aquarius. Credit: Will Gater

Sporadic meteor 13082013Not a Perseid! A short sporadic meteor points the way (sort of) to M31. Credit: Will Gater

Summer stargazing on Dartmoor

Despite the short nights, and often poor weather, the summer night skies offer some spectacular celestial sights. My favourite areas to observe at this time of year are the rich swathes of the Milky Way in Cygnus, Sagittarius and Scutum. These regions are packed with dense starfields, glowing emission nebulae and some of the night sky’s finest star clusters.

On Saturday I spent the evening on Dartmoor imaging these wonderful parts of the sky. I wanted to capture a large portion of them in each frame, so I used a 50mm prime lens on my unmodified Canon 550D DSLR, which itself was mounted on an HEQ5 Pro mount.

The first image below shows part of the Sagittarius, Scutum & Serpens region. Several Messier objects are visible in the frame, including: M8 (the Lagoon Nebula), M20 (the Trifid Nebula), M22, M17, M16 (The Eagle Nebula) and M24. The second shot shows a region of the Milky Way in the constellation of Cygnus. The red glow of the North America Nebula (NGC 7000) and the nebulosity around the star Sadr (right of centre) are apparent. You can also, just, make out the two main fragments of the Veil Nebula right on the very bottom edge of the frame. The shot with the silhouetted tree is a single 15-second exposure, at ISO 1600, with the lens wide open at f/1.8.

Dust lanes weave through the Sagittarius, Scutum & Serpens region. Credit: Will Gater

The Milky Way near the bright star Deneb (top) in Cygnus. Credit: Will Gater

A lone Dartmoor tree stands silhouetted against the summer Milky Way. Credit: Will Gater

Live astrophotography from the Brecon Beacons

One Show presenter Lucy Siegle talks to Will live from the Brecon Beacons. Credit: BBC

I had great fun on Wednesday night in the Brecon Beacons filming a series of live segments about astrophotography for the BBC’s The One Show. The idea behind the evening was that I would help a group of twenty amateur photographers take their first images of the night sky before judging which was the best shot. When we arrived at the filming location the sky was filled with clouds, but as the Sun set the clouds thankfully dissipated and the photographers managed to capture their pictures (even despite some quite substantial haze).

If you missed the programme, and are in the UK, you’ve got a few days left to catch it on the BBC’s iPlayer; the astrophotography bits can be found here, here and here. And if you’ve captured an astro image lately that you’re particularly pleased with, don’t forget to send it into the 2013 Astronomy Photographer of the Year competition, which is now open for entries.

Marvelling at the mountains on the Moon

Over the last few nights we’ve had some clear skies and good seeing conditions here in the southwest of the UK. On Monday night I spent 3 hours capturing a 50 pane mosaic of the whole of the visible portion of the Moon while last night I decided to focus on the wonderfully rugged region around the lunar Alps and the crater Plato.

Both images are shown below – do click on them to see the full size versions, especially the whole-phase mosaic. They were captured with a Meade 8-inch LX200R Schmidt-Cassegrain telescope and an Imaging Source DMK21AU618.AS CCD camera; the Plato/lunar Alps image is a mosaic of 17 panes made using an additional 2x Barlow lens.

50 pane mosaic of the Moon on 18 February 2013. Credit: Will Gater

Crater Plato and the lunar Alps on 19 February 2013. Credit: Will Gater

 

Jupiter and the Moon shine through steady skies

Here are a few pictures of the Moon and Jupiter that I captured on Friday night/Saturday morning under some great seeing conditions – in fact the best seeing conditions I’ve seen all year. All of the images were taken with an 8-inch Schmidt-Cassegrain telescope, an Imaging Source DMK21AU618.AS CCD camera and a 2x Barlow lens. To create the colour Jupiter image I also used a set of Astronomik RGB filters and a 3x Barlow lens (I used the 3x Barlow for the Atlas/Hercules shot too).

Jupiter and the Great Red Spot. Credit: Will Gater
Posidonius_01122012The rille network within crater/walled plain Posidonius. Credit: Will Gater
Janssen_01122012The walled plain Janssen and the crater Fabricius (top). Credit: Will Gater
CleomedesLong shadows on the floor of the walled plain Cleomedes. Credit: Will Gater
DorsaGeikieCrater Messier (left) and Dorsa Geikie (centre). Credit: Will Gater
gocleniusCrater Gutenberg (upper left). Credit: Will Gater
VallisRheitaVallis Rheita and crater Rheita. Credit: Will Gater
copernicusCrater Copernicus lit from above. Credit: Will Gater
atlas_herculesCraters Atlas (right) & Hercules (left). Credit: Will Gater
RimaCauchySinus Concordiae & Rima Cauchy. Credit: Will Gater

Dartmoor’s delights make up for lacklustre Leonids

Jupiter with the Hyades & Pleiades (also shows NGC 1647 & NGC 1746). Credit: Will Gater

Last Saturday I headed up onto Dartmoor in the hope of seeing a few meteors from the Leonid meteor shower. Even though I had clear, dark skies on my side, the Leonids put on a rather feeble display this year; in a 3-hour observing session I only saw four, though I did see around twenty respectable sporadic meteors. After a good few hours of trying (and failing) to catch one of the blighters on camera I gave up and decided to have a go at imaging some other targets.

I couldn’t resist photographing the superb sight of Jupiter with the Hyades and Pleiades star clusters. The image above is a stack of six three-minute exposures taken at ISO 400. I used an unmodified Canon 550D DSLR and 90mm lens with an HEQ5 Pro mount (which was autoguided by a Sky-Watcher SynGuider attached to an 80mm refractor). The picture of the North America Nebula below was taken with the same setup, but it’s composed of about 30 minutes of exposures at IS0 400.

The North America Nebula (NGC 7000) & Pelican Nebula. Credit: Will Gater

Stargazing from the Gower


Rose and I admiring the summer Milky Way. Credit: Will Gater

With the awful weather we’ve had here in the UK this summer I’ve had hardly any astro images to share here on the blog. Thankfully, things seem to be improving* as we enter autumn. Here are a few shots I captured last weekend while camping in the Gower with my wife, Rose.

We camped at Three Cliffs Bay on the south coast. It’s a beautiful part of Wales with clear views out over the Bristol Channel to the south — perfect for observing, low altitude, summer objects like the Lagoon Nebula and the many interesting star clusters in and around Sagittarius and Ophiuchus. The skies were wonderfully dark looking out over the Bristol Channel to the southwest; sadly the same can’t be said for the view looking east, towards Swansea and Port Talbot, where substantial light pollution masked everything but the brightest stars.

Anyway, if you’d like to see some of the objects in these images yourself you’ve got a few weeks before they disappear into the twilight for a while — September’s Sky at Night Magazine has a great observing article on pages 32-37 to get you started.

* I may regret writing that.


The Scutum Star Cloud, within the Milky Way. Credit: Will Gater

The Eagle Nebula (M16), with the ‘Pillars of Creation’. Credit: Will Gater

The Lagoon and Trifid Nebulae among the Milky Way star fields. Credit: Will Gater

Observing the 2012 transit of Venus

The 2012 transit of Venus imaged at h-alpha wavelengths. Credit: Will Gater

A week ago I travelled to the Greek island of Kos to observe the 2012 transit of Venus – a rare celestial event where the planet Venus drifts in front of the Sun’s disc, as seen from Earth.

The hotel where I stayed was located on the north-eastern end of Kos, close to the village of Psalidi. I had chosen this site for two main reasons. The first was its shoreline location and clear view to the northeast out over the Aegean Sea.

Only the distant mountains of Turkey interrupted the horizon, but as they reached less than a degree above the horizon I knew they wouldn’t obscure much of the transit. Besides, when the Sun is that low down the distorting effects of the atmosphere are so great that getting a sharp view of the transit (when the Sun is barely a degree above the horizon) would be almost impossible.

Although the transit would be well underway by the time the Sun rose from Kos, the island’s position on the Earth meant that around 2 hours of the transit would still be left to observe. And the Sun would reach an altitude of about 20 degrees, from Kos, before Venus moved off the solar disc.

A view of the north-eastern horizon from my observing site near Psalidi.

The second reason I chose Kos as my transit observing location was that the eastern end of the Mediterranean had the best weather prospects in Europe for the time of the transit. I later found out that I wasn’t the only one with the eastern Med in mind as an observing site, as several other astronomers — including well-known German astronomer Daniel Fischer — travelled to Rhodes.

Moonrise over Kos two nights before the transit. Credit Will Gater

Imaging the transit with a static photo tripod, PST & DMK 21AU618.AS CCD camera

I was able to take two telescopes with me to Kos. The first was the de-mounted optical tube assembly from an ETX90EC with a Baader AstroSolar Safety Film solar filter. I have used this telescope on observing trips several times, including the 2006 total solar eclipse in Turkey, as its compact size is perfect for travelling. However this time because of hand luggage weight constraints I had to carefully pack it up and send it to Greece in my hold luggage.

Unfortunately a quick star test on the night of my arrival in Kos showed that it had slipped slightly (but noticeably) out of collimation — so my transit images from the ETX OTA are not as sharp as they could be. The second scope I took with me was a Coronado PST. I carried this as hand luggage along with a DMK 21AU618.AS CCD camera and the Baader solar filter.

A test image captured with a static photo tripod a few days before the transit.

Both telescopes were used, one at a time, with a heavy photographic tripod. Imaging the Sun with my Canon 550D DSLR and the ETX scope was a fairly easy affair — only single, short, exposures were needed. However the PST/DMK/static photo tripod setup presented a few imaging challenges. Namely, how to capture an AVI video through the DMK/PST without blurring the image or letting the Sun drift out of frame while the video was being captured.

There was no way I would be able to take a tracking mount with me to Greece; so in the months leading up to the transit I practiced hand guiding the alt-azimuth controls of the photographic tripod so that the Sun stayed in frame, in roughly the same location. It was difficult to say the least, but it did work and Registax was able to process the videos without any ‘ghost’ images. Above is a test — hand tracked — PST image captured two days before the transit.

Dawn breaks over Kos on the morning of the transit.

The morning of the transit was clear, with only a few thin haze clouds hugging the horizon. Yet as the dawn began to break a few clouds started to bubble up over the coast of Turkey. One cloud in particular (seen in the image below) had me worried, as it was threatening to move right in front of where the rising Sun was about to appear. Thankfully though these clouds moved away — and some of the haze appeared to dissipate — a few minutes before the first rays of sunlight appeared over the mountains.

The north-eastern horizon moments before sunrise.

My first view of the transit was, as expected, heavily distorted by various atmospheric undulations. It was actually quite surreal to see the silhouette of Venus, through the eyepiece, being smeared up and down — as if someone was stretching and compressing the whole solar disc. The series of images on the left (click the thumbnail to get a bigger version) shows this effect clearly; they were taken just as the Sun was appearing over the distant Turkish mountains.

As the Sun climbed higher in the sky the atmospheric distortion lessened and I was able to begin imaging the transit in earnest. Below are a few of the shots I was able to capture.

The 2012 transit of Venus imaged at h-alpha wavelengths. Credit: Will Gater

A full disc view taken with a 550D, ETX90EC & Baader solar filter. Credit: Will Gater

The 2012 transit of Venus imaged at h-alpha wavelengths. Credit: Will Gater

The 2012 transit of Venus imaged at h-alpha wavelengths. Credit: Will Gater

The development of the famous ‘black drop’ effect. Credit: Will Gater

Almost over! Venus edges off the solar disc. Credit: Will Gater

Towards the end of the transit a large cumulus cloud bank formed to the southeast and began to slowly drift in the direction of the Sun. As Venus was moments away from slipping off the solar disc, the wispy edges of the cloud began to encroach onto the Sun until finally the transit was completely obscured. And so began the 105 year wait for the next time that Venus glides gracefully across the face of our star.

One final note: throughout the transit I was using specialist solar filters to observe and photograph the Sun. Never point an unfiltered telescope, unfiltered pair of binoculars etc. at the Sun. You will damage your eyes and almost certainly blind yourself. If you want to observe the Sun only use specialist certified solar filters that have been fitted correctly (and thoroughly checked) and that have been purchased from a reputable astronomical supplier. Be sure to follow any usage instructions carefully. Finderscopes etc. should also be filtered or removed.

All images © Will Gater 2012

Photography Monthly interview on astrophotography

I had a lot of fun talking about astrophotography to Fiona Keating from Photography Monthly magazine a few weeks ago. The 4-page interview appears in the June issue of the magazine, which has just hit newsstands. In the interview I talk about some of the methods and equipment that can be used to take pictures of the night sky and the technical challenges astro imaging creates.

So if you’re thinking of getting into astrophotography, why not pick up a copy of the magazine and start snapping. And if you capture a great image, remember there’s a ‘best newcomer’ prize in the Astronomy Photographer of the Year competition.

AR1476 and the seething Sun

Prominences leaping from the limb of the Sun on 11 May 2012. Credit: Will Gater

It was hard to decide where on the Sun to look first yesterday with all the activity that was going on. AR1476 was, of course, taking centre stage but there were also numerous filaments scattered over the disc, while around the limb there were several impressive prominences.

I managed to capture a few pictures of what was going on, but sadly the seeing conditions were poor and so the detail in the images isn’t very good.

The picture above and the first two pictures below were taken with an Imaging Source DMK 21AU618.AS CCD camera (shooting at 60FPS), a 2x Barlow lens and a Coronado PST hydrogen-alpha filtered telescope. The last image was taken with the DMK 21AU618.AS on an ETX90EC OTA fitted with a white-light solar filter.

A large prominence extends above the solar limb. Credit: Will Gater
AR1476 as seen in hydrogen alpha light on 11 May 2012. Credit: Will Gater
AR1476 imaged with a white-light solar filter on 11 May 2012. Credit: Will Gater

A word of warning: never point an unfiltered telescope, unfiltered pair of binoculars etc. at the Sun. You will damage your eyes and almost certainly blind yourself. If you want to observe the Sun only use specialist certified solar filters that have been fitted correctly (and thoroughly checked) and that have been purchased from a reputable astronomical supplier. Be sure to follow any usage instructions carefully. Finderscopes etc. should also be filtered or removed.