How I Learned to Stop Worrying and Love the Night Sky

Messier 13: The Great Hercules Globular Cluster

"For my part, I know nothing with any certainty but the sight of the stars makes me dream." – Vincent Van Gogh

First: apologies for the lack of posts recently. It turns out that "mapping Mars from my back garden" is a tough act to follow; also, the whole lockdown "thing" tends to put a limit on where you can go (on this planet at least).

On the plus side, I'm pleased to say I recently became a contributing writer for the astronomy website Love the Night Sky. If you're new to the hobby, or coming back to it after a break, this site has all the information you need to get up and running. Unlike many other astronomy-themed websites and YouTube channels (which tend to obsess about getting the perfect astrophoto with little or no information about the object being photographed), the emphasis here is on learning and observing: helping you find your way around the night sky, while enriching your experience with scientific and historical context. I've been observing for years, but it's that sense of there always being more to see and more to learn that keeps me coming back to the eyepiece again and again.

My first three articles (with more to follow) are available via the links below, covering some of the finest deep-sky objects you can see though a telescope. Each article explains what the object is, when to see it, how to find it, and what you can expect to see through telescopes of different apertures, as well as links to other sources of information.

M11: The Wild Duck Cluster

M13: The Great Hercules Globular Cluster (as shown in the image above)

M8: The Lagoon Nebula

All three of these objects are visible on summer nights, and you don't need a large telescope to see them. So, if the sky is clear and the stars are out, why not grab a pair of binoculars, turn your lights off, and enjoy the view? I could say more, but a certain very famous professor has already said it for me:

"Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist. Be curious." – Stephen Hawking

UPDATE: More articles now available, as linked below:

M80: Globular cluster in Scorpius

M57: The Ring Nebula in Lyra

M72: Globular cluster in Aquarius

M77: Spiral galaxy in Cetus

M76: The Little Dumbbell Nebula in Perseus

M52: Open cluster in Cassiopeia

M37: Open cluster in Auriga

M78: Reflection nebula in Orion

M42 (and M43): The Great Nebula in Orion

Remember: a telescope doesn't take up space; it gives you space.

A Very Photogenic Comet

"Comets are like cats: they have tails, and they do precisely what they want." - David H. Levy

I must admit, when I first heard that comet C/2020 F3 (NEOWISE) was on course to reach naked-eye visibility, my initial reaction was one of mild scepticism. After all, similar predictions had been made about comet C/2019 Y4 ATLAS (which promptly disintegrated) and comet C/2020 F8 SWAN (which also fizzled out). However, NEOWISE didn't just live up to expectations, it surpassed them - becoming certainly the best comet I've seen since Hyakutake and Hale-Bopp, the two Great Comets of the 90s.

Bright though it is however, NEOWISE (named after the space telescope that discovered it) is by no means a Great Comet like those two. Nor is it the first significant comet of the digital age (that honour must go to the spectacular Comet C/2006 P1 McNaught), but - due to its favourable placing for observers in the northern hemisphere - it's likely to become the most photographed comet in history (at least until the next bright one comes along). This is the fifth comet I've pointed a camera at, and it's easily the most photogenic, even if it did require me to leave the house at some very unsociable hours.

Comet NEOWISE should remain visible for the rest of the month, although it will - barring outbursts - become progressively fainter. At time of writing NEOWISE can be found in the late evening sky below Ursa Major (see the links at the end of this post for finder charts). You don't need a telescope to spot it; if your sky is dark enough it should be visible to the naked eye, and a modest pair of binoculars will give a really good view.

You don't necessarily need a long lens either if you want to try and photograph it (the image at the top of this post was taken with a standard 50mm prime). However, you will need a tripod and some means of operating the shutter without touching the camera (either a timer delay or a cable release). As I was shooting at a high ISO I also stacked multiple images and subtracted dark frames to further improve the signal-to-noise ratio. Here's another one taken at 400mm, showing the characteristic golden dust tail:

It's worth making the effort to see Comet NEOWISE at least once before it's gone; after all, it won't return to the inner solar system for nearly 7,000 years.

Links:
How to see Comet NEOWISE over the coming nights (Sky at Night Magazine)
Comet NEOWISE dazzles at dusk (Sky & Telescope)

Meet the Galactic Neighbours

What's the most distant object you can see with the naked eye? Unless you live near a dark-sky site (and have exceptional eyesight) the answer is most likely the Andromeda Galaxy. To find it, go outside on a clear, moonless autumn evening and allow a few minutes for your eyes to adjust to the dark. The Andromeda Galaxy is located about midway between the square of Pegasus and the "W" of Cassiopeia.

You should be able to see a faint smudge of light that increases in size when you look slightly to one side of it. (If you're not sure you're looking in the right place, use a pair of binoculars and you should spot it straight away.) That faint smudge of light takes on new meaning when you consider it's a vast complex of stars and dust and gas 220,000 light years across and 2.5 million light years away. It's also barrelling towards us at 110 kilometres per second, so if you hang around a few billion years it's going to get a whole lot bigger and brighter.

In the meantime we'll have to make do with views like the one below. This is an image I made from an hour's worth of exposures using a Canon 80D DSLR and a Tele Vue-60 refractor (focal length approximately 400 mm):

Telescopically, M31 is impressive whatever instrument you point at it, but picking out the kind of detail shown in the photo above is more of a challenge than you might think. On a good night I can see the two dark dust lanes northwest of the core region, and also a vague suggestion of clumpiness in the spiral arms, particularly around the star cloud NGC 206. The two companion galaxies, M32 and the fainter M110, are also easy to spot.

Andromeda and our own Milky Way are the two largest members of the Local Group - a modest collection of at least 50 (mostly dwarf) galaxies occupying a region of space 10 million light years across. Roughly 14 degrees south of M31 is the third largest member of the Local Group, M33 (aka the Triangulum Galaxy). Here's an image I took at the end of August, using the same camera/telescope combination, this time assembled from two hours of data.

Although M33 is only little further away (relatively speaking) than M31 at 2.73 million light years it has a very low surface brightness - and is consequently much harder to see. It's also very sensitive to light pollution. Oddly enough I always found this galaxy easier to spot in a pair of 7x50 binoculars than in my 4-inch refractor. Even on a good night it was vanishingly faint.

In the 10-inch Dobsonian it appears as an extended misty patch of light with a tiny star-like nucleus. On a favourable night I can just about make out the two main spiral arms (the northern one is brighter and easier than the southern one). Higher magnification reveals a prominent misty spot 13 arcminutes northeast of the nucleus (visible as a blue blob in the image above), lurking close to an 11th magnitude foreground star. This is NGC 604, one of the largest star forming regions in the Local Group. It's a whopping 1,500 light years across, which is roughly the distance between here and the Orion Nebula.

Both M31 and M33 have been extensively studied by astronomers using the Hubble Space Telescope and, as you might expect, the images are spectacular:

Hubble's high-definition panoramic view of the Andromeda Galaxy
Triangulum Galaxy shows stunning face in detailed Hubble portrait

Photographing the 2015 Total Lunar Eclipse

Lunar eclipses aren't that rare - certainly not as rare as some uninformed sections of the media would have you believe, but I hadn't photographed one since March 2007, so I stayed up till stupid o'clock the other week to get some images of the so-called Super Blood Moon eclipse. The wind was a little gusty, but fortunately the clouds didn't interfere.

One thing the photos don't convey is just how much the moon dims during totality. (The reason it doesn't go completely dark is because it's illuminated by sunlight refracted through the earth's atmosphere. Or to put that in a slightly more lyrical way, an observer standing on the moon during an eclipse would see all of the earth's sunrises and sunsets compressed into a beautiful ring of light.) The first image in the sequence above (the barely eclipsed moon) was shot hand-held with a 1/1600 second exposure at ISO 800. The last shot (fully eclipsed) was taken on a tripod with a cable release, with the mirror lock-up function enabled; exposure time 1/2 second, ISO 1600. At long focal lengths (400 mm and above), these slow exposure times can be problematic. Shoot for anything longer than about half a second and the earth's rotation will start to smear the image.

So, as is often the case in astrophotography, there's a trade-off to be made. Do you under-expose and increase noise, or do you expose correctly and lose detail? A tracking mount which will correct for the earth's rotation is one way around the problem, but the good ones don't come cheap. Another method (if you find high ISO noise objectionable) is to shoot lots of under-exposed images one after the other, stack them in RegiStax or AviStack to increase the signal-to-noise ratio, and then push the exposure in Photoshop. I did think about doing this, but it was late and I was tired and it seemed like a lot of effort given that I still had several hundred photos from the Camargue to sort through (a post on that is coming soon).

Maybe it's something I'll try for the next eclipse in 2018; or maybe by then cameras will have progressed so much that high ISO noise won't be a big deal... Anyway, to tide us over till then, here's an uncropped view of the eclipse taken at ISO 6400, and carefully pushed in PS to bring out the background stars. A red full moon surrounded by stars; now that's a sight worth staying up for.

Sir Patrick Moore - A Belated Tribute

The final edition of The Sky at Night to feature Sir Patrick Moore aired last night on BBC 1 (and will be showing again as an extended episode on BBC 4 later in the week), so this seems like a timely moment to share a few thoughts I originally posted on the Sky at Night Flickr group a few weeks ago.


Many moons ago, my mum wrote to Sir Patrick, asking him for advice on what telescope to buy her astronomy-obsessed son, and he very kindly sent one of his famous hand-typed letters in reply, offering his usual brand of no-nonsense wisdom.

Years later, after going on to study astronomy at university, I was fortunate enough to attend one of Sir Patrick's BAA lectures at the University of Kent, in which he spoke about Mars for an hour (without notes). It was the period straight after lunch (a tough time to give a lecture), but he kept the whole audience captivated with his energy and boundless enthusiasm.

And just last month, I was watching The Sky at Night on BBC 4 when I was pleasantly surprised to see one of my photos featured in an item about the planet Mercury.

RIP Sir Patrick, and thanks for everything. You will be missed.

See also:
The Sky at Night on BBC iPlayer (available until Sunday 13 January)
The Sky at Night programme page
BBC Stargazing LIVE (starts Tuesday 7 January)
BBC Sky at Night and Stargazing LIVE Flickr page