Archive for the ‘science’ Category

A mote of dust suspended on a sunbeam

1 June 2009 Comments off

As you should know by now — as I’ve quoted him often enough — Carl Sagan is my hero. Here’s something beautiful, humbling and inspiring from a lecture he did in 1994, two years before his untimely death:

Carl Sagan quote

Hat tip to irReligion.

Another evening looking up and out

18 March 2009 Comments off

Orion Nebula & Trapezium (from Astropix)As I checked the evening’s weather forecast before leaving for work I was delighted to see that both MetCheck and Astroforecast were forecasting clear skies, making the evening’s activities a given. I was very keen to get out again as I took delivery of a moon/atmosphere filter and 6.3mm eyepiece earlier this week, the latter stretching my telescope’s magnification ability from 273X to 476X (with 2X Barlow) – silly amounts, but nice to have.

Once the sun had set and I’d submitted this evening’s GLOBE at Night 2009 observation and watched the scheduled ISS pass (it was brilliant!), I setup outside. Blissfully, the neighbours weren’t using the back of their houses, so house lighting washing over me was at a minimum. The light pollution was still pretty ugly, but the particulates in the air must be low, so there wasn’t the obscene scattering I experienced last time. In all, clear skies making for fantastic stargazing conditions. First up I decided to try to zero the scope on Polaris itself, rather than use a compass, and this seemed to make the tracking motor work better. It was certainly a lot easier and less prone to error my nearby metal objects (including the batteries in the red LED torch I hang around my neck).

Still with the Messier Marathon challenge in my mind, I wanted to see how many Messier Objects I could see—it turns out that it wasn’t many (timing, valley wall, other light sources, etc)—and give the new eyepiece and filters a run for their money.

The Pleiades (M45) were beautiful at low magnification, and with my Mak at 60X I was just able to contain them within the one view. Increasing magnification gave so much more detail, but obviously lost the frame of reference.

The Orion Nebula (M42) was frankly awesome at 476X—yes, I had to give it a go. It was so good that I could clearly delineate the nebulosity and dust shadow, and the Trapezium Cluster was clearly visible as 4 distinct stars, along with the 3 bright stars that arc out like an arm away from it. It was magnified enough that I had to move the telescope to view M43.

The Andromeda galaxy (M31) was a bit of a disappointment for me, as it was quite low on the horizon where I was (fences, houses, etc) and the neighbours in that direction chose this time to do their nightly illumination of every corner of their top floor. I was barely able to see Mirach, so I had no hope of seeing M31 in all its glory.

Capella was crisp and bright. Betelgeuse was its beautiful red colour. I read the other day that Castor is a “double double double” star system (ironic that one of the Gemini twins is actually three sets of twins), so wanted to see if I’d be able to separate any least 2 objects. Thinking that Castor was the left head of Gemini, I viewed it with slightly disappointment as not being able to separate it out. Of course it wasn’t until I got inside that I realised I’d been trying to separate Pollux. Idiot.Saturn (from NASA)

Lastly, it was time to try Saturn at 476X. Oh man, what a sight! Even with the dew by that time reducing visibility, it was a stunning sight. So much bigger that I was able to make out the Cassini Division, even though the rings are almost flat now.

This coming Saturday marks the monthly meeting of my local astronomy society, so I am looking forward to attending for the first time. And the following weekend is their IYA 2009 event, with stargazing for all-comers on the Friday and Saturday evenings, and sun viewing on the Saturday and Sunday. If you’re in or near Berkshire and interested in coming along, leave a message here.

So there ends another evening of chilly delight, discovery and rediscovery. It’s again reinforced the need to plan out your viewing sessions based upon date and time, and therefore visible objects, particularly in my backyard environment. However, once I get a proper carrying box, I’m going to make a foray to the nearby rugby club that’s in a more rural setting than I am. That should make for a completely different experience.

Categories: science Tags: ,

Citizen scientists: GLOBE at Night needs you!

16 March 2009 Comments off

Orion constellation (image from NASA)Those of you interested in astronomy and/or concerned about light pollution might like to know that today, 16 March 2009, is the start of GLOBE at Night (GaN) – a global initiative for UNESCO’s International Year of Astronomy 2009. GaN is a citizen science project that anyone can participate in: school children, parents, teachers, enthusiasts… anyone.

It simply involves viewing the magnificent Orion constellation with the naked eye from 16-28 March (or up to 7th April, if you like) 2009 in the evening after sunset, comparing what you see to a chart and reporting the results to the GaN website. It’s that simple!

Not only does it get you out of the house and under the night sky, but it gives you a chance to participate in science on a global scale.

As the Dark Skies Awareness website says:

At least 2 out of 5 Americans, 1 out of 6 Europeans and 1 out of 10 people worldwide have never seen 90% of the stars in our night sky. With half the world’s population now living in cities, this problem is only getting worse.

And read the first comment of this New Scientist article to place it into perspective.

The project’s function is to raise public awareness in the astonishing amount of light and electricity we waste for no useful purpose. So join in GLOBE at Night and the universe will open up to you… quite literally!

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In which I learn about clear skies

14 March 2009 Comments off

Imagine my delight to look out my living room window after sunset to see that the Astroforecast clear sky prediction was coming true, and that the usual grey dome of sky was actually a reddish purple. Stargazing! So once the sun had set properly I placed the telescope outside – to allow it to acclimatise to the temperature difference – and worked out a list of Messier objects to view, as I quite like the idea of doing the Messier Marathon.

I went out to join the telescope 45 minutes later but my timing may have been off, as both my neighbours had their kitchen/dining room lights on, the back neighbour had every single light on (inside and outside!), and the sky had quite a bad orange glow. At first I thought the latter was something to do with the sun, but I saw it was a dome that went all around the horizon and at least 45° up from it – leaving just a small darkened cap with stars coming through. I couldn’t see the Pleiades or nebulae around Orion’s belt, Betelgeuse was okay, Aldebaran was barely visible, and Procyon was washed out.

An hour later I was becoming increasingly frustrated, my neighbours still had their lights on (I can’t blame them, of course), and the orange half-dome had no intention of going away. It was bad enough that Orion’s belt effectively set 20° before it went below my roof line. I did get a nice view of Saturn and Titan, but that was it – time to call it a night.

It turns out that clouds are not the only thing that matter when you’re viewing the night sky. Clarity of the atmosphere seems to make a huge difference, as does the time of day (and potentially day of week) in terms of the human factor – at least when not at a dark sky site. This may be obvious to you, but I grew up on the outer edge of suburbia in a Mediterranean climate where there weather and skies are clear 300 days a year. Careful night viewing planning is uncharted territory for this antipodean…

Light pollution is a truly appalling blight for the urban or suburban stargazer, particularly as it’s the easiest of all pollutants we emit to prevent. I accept it’s unreasonable to expect our neighbours to contain their indoor lighting (it really is their right to use inefficient lighting and waste power, though is something of which I’ve always been conscious), but my crime-free neighbourhood and the large town I live on the edge of is lit up like an orange Christmas tree from sunset to sunrise. Why? The oft-quoted reason is crime prevention and safety, and I concede there are places where that does apply – particularly in pedestrianised urban areas – but there is a growing body of evidence to show that it makes little if any difference in the majority of suburbia and rural areas.

I’m beginning to think the British Campaign for Dark Skies (CfDS) and International Dark-Sky Association (IDA) are worthy organisations, and will be looking into them in detail. I intend to bring it to the attention of my local residents’ association, and write to my council and member of parliament. My MP may well disagree with me (he has in the past), but at the very least it will raise his awareness of the issue.

There has to be a better way of using public lighting (and non-renewable resources) than floodlighting the planet during darkness. Anyone?

Unexpected Saturnian delight

9 March 2009 Comments off

Since my initial test use of the telescope last Thursday evening, the weather here has been… let’s call it sub-optimal. Aside from the usual rain and such one gets this time of year, the British Isles seem to get more than its fair share of high-level total blanket cloud cover. It’s so frequent and pervasive that I long ago began referring to it as “English blue”. I suspect it’s something to do with the Gulf Stream that also makes this little part of the world far warmer that it should otherwise be, and makes the west coasts of Ireland and Scotland quite verdant and… soggy. Swings and roundabouts, I suppose.

Yesterday afternoon I was visiting friends for Sunday lunch (how civilised!) and we were amused by the blustery weather and hail for much of the afternoon. So I was completely unprepared, when I finally left later that evening, to look up at a crystal clear sky with only minimal, fast-moving cirrus. I drove home liked an excited little boy, knowing I’d very soon be stargazing. Since my last viewing I’ve set the telescope up correctly, read the manuals, and have an idea of what I want to view this time. It was also a good time to test my back garden as a viewing platform – the street lighting at the front being prohibitive soon after night vision is gained.

Running Man Nebula (image from NRAO)

Running Man Nebula (image from NRAO)

On the mental list tonight was Betelgeuse, Rigel, Orion Nebula (M42), Horsehead Nebula (IC434), Aldebaran, Sirius, Procyon, Pleiades (M45), Andromeda Galaxy (M31), Saturn and the Moon. There were a few more I’d have liked to see, but the Moon was far too bright.

With the 2 eyepieces and Barlow, I had 60-273X magnification available to me. Neither Rigel nor Sirius were visible, as the former had set below my roofline to the west and the latter hadn’t risen above the valley wall to my south, but Betelgeuse, Aldebaran and Procyon came up nicely. Though even at 273X they were just slightly brighter lights, with the exception of Betelgeuse and Aldebaran whose redness became nicely visible. The Pleiades were also very nice.

When I setup to view the Orion Nebula, because of the inversion of the image I didn’t realise at first that I was actually viewing the Running Man Nebula (NGC1977) but was very impressed with the 5 bright stars I could see against the cloudy background. I think it is more impressive than the Orion Nebula when view through a telescope.

The reason is that it appears black and white to the eye, as there’s something about the colours being indiscernible in real-time over those distances, whereas a camera’s long exposure can pick up the colours. I’d read about this, but it’s the first time I’d experienced it. I also think it was the first nebula I’d ever seen, as I don’t recall ever seeing one when I did astronomy as a child.

Flame Nebula (image from AstroCruise)

Flame Nebula (image from AstroCruise)

Next was an attempt to view the Horsehead Nebula, but I couldn’t remember exactly where it sat relation to Alnitak. So instead of viewing it, I ended up viewing the lovely Flame Nebula (NGC2024). Again, it was in black and white, so my mind’s eye filled in the colour gaps, and it was most impressive.

Then there was the Moon, and again it took my breath away. It was almost full, but there was enough shadow left to allow me to focus on the craters at the shadow’s edge and observe them in relief against the background. It was amazing to see. And when I added the 11mm eyepiece with 2X Barlow, I was able to see a very high level of detail. Smaller impact craters were easy to examine, and each Sea took up the entire view.

Tonight I was determined to view Saturn, as I missed it last week. For those of you familiar with the fantastic but now-departed TV series Firefly, you’ll know the camera technique of showing a dot in the distance, then there’s like a “click zoom” which shows the identifiable object at a distance, then another “click zoom” and it will be closeup (in the show it’s typically used in space scenes outside the ship). That’s exactly what it was like viewing Saturn. To the naked eye and when lining it up in finder-scope it was just a bright ‘star’, then viewing with a 25mm eyepiece it ‘clicked’ as a tiny but clearly identifiable yellow/biege planet with a –strikethrough– line of flattened rings, and then with a 5.5mm eyepiece (11mm with Barlow) it was much bigger and breathtaking. It just sat there, quietly inspiring awe.

And much to my surprise, I was able to identify 3 of its moons: Tethys, Titan, and Iapetus. I was initially unsure of Tethys and Iapetus, but a check of Starry Night and online confirmed it was.

Lastly, I planned to have a look at the Andromeda Galaxy, but at exactly the wrong moment my neighbours decided it was their bedtime, so switched on every light on their top floor which – when combined with the British dislike for closed curtains – meant that my back garden (the lawn part is raised) was completely flooded with bright white light for about 30 minutes. This, along with the almost full Moon, washed out my night vision – it was time to call it a night.

Even packing up under such circumstances, I was extremely happy with the night’s viewing. I’d seen most of what I’d intended, and had replaced some of the desired objects with other ones, and I’d had good opportunity to practice my constellation identification.

I’ll not pretend that I didn’t have some help, and that came in the form of the brilliant GoSkyWatch planetarium software for the iPhone. Not only does it look great, but it has an excellent database of objects and is extremely easy to use. And its “night mode” ensures that your night vision doesn’t suffer (my only niggle is that the searching and setting screens are still full brightness black/white), making it easy to use during your stargazing activity. I find this easier to see and more convenient that a planisphere, as with that I’d need to juggle the red torch, too. The software is worth every penny of its £5.99 (US$9.99) price tag.

A great evening, in all. And as the title says, both Saturn and the opportunity to view at all was an unexpected delight. Can’t wait until next time!

Categories: science Tags: , ,

Stargazing anew

6 March 2009 Comments off

Sky-Watcher Skymax 127 SupaTrakAfter much consideration, and with my upcoming studies in mind (or at least that’s how I justified it to the accountant part of my brain), I bought a telescope earlier this week and it was delivered yesterday. I spent a few evenings considering my main options – refractor, Newtonian, Maksutov, Schmidt-Cassegrain, or Dobsonian-mount Newtonian – and speaking with various people, I whittled the choices down to either Sky-Watcher’s Explorer 130P or Skymax 127 (both with SupaTrak motorised mount). While there are undoubtedly better telescopes on there in this aperture range (the number refers to aperture in mm), this shortlist came about due to reviews given, price, and availability. Both have received excellent reviews, and they’re readily available.

The Explorer is a Newtonian, so is considered fine for general astronomical observation due to its aperture and field of view, and the Skymax is a Maksutov, so is considered ideal for up-close examination of objects. As I understand it, the reasons for the distinction are based upon:

  • Size of the primary mirror. The Newtonian is 130mm and the Maksutov is 127mm, so both roughly 5″.
  • Amount of light reaching the primary mirror. The Maksutov has quite a large secondary mirror and corrector plate (meniscus lens) which together reduce the amount of incoming light more than the Newtonian’s relatively small secondary mirror.
  • Focal length of the telescope. The Newtonian is 650mm and the Maksutov is 1,500mm, due to the way the mirrors fold the incoming light to the eyepiece.
  • Focal ratio (focal length divided by mirror size) will be familiar to all photographers as f-stop (to control depth of field). The Newtonian is f/5 and the Maksutov is f/11.8. The higher the focal ratio, the narrow the field of view.

A Newtonian has a wide FOV that allows it to naturally see a wide area of the sky, meaning it can fit a large nebula or a planet quite easily, but will need additional magnification to look closer; whereas a Maksutov has naturally high power but a narrow FOV, meaning it might not be able to view all of the largest nebulae at once, but is superb at picking out detail on what it can see. However, after discussing the matter with a number of amateur astronomers, it seems that at this level (aperture and price), the distinction is really not an issue.So… I bought the Skymax 127 (pictured).

I think I’ve got all that right. If not, please let me know.

It’s probably worth saying at this point that I’ve made enquiries with my local astronomical society, and plan to go along to their next meeting with a view to joining. With a topic like astronomy, you really can’t beat being part of a skilled community, learning from them and participating in their activities (including dark sky site nights/weekends).

The telescope was delivered to my workplace yesterday, though I had to wait until I got home before I could unwrap it. And that was the first thing I did when I walked in the door – opened the Russian dolls (it was a number of boxes within a box within a box within a box – no kidding), made sure everything was there, read as little of the documentation that I could get away with, and set up shop on my front porch. I hadn’t aligned the finder-scope, didn’t level the tripod (it has an inbuilt bubble level), and only performed a cursory zeroing of the motor mechanism, so I wasn’t going to get a quality experience, but I just wanted to look through it already!

Venus was still ~10° above the horizon, so I lined up on that first and was pleased when the bright, crescent sliver appeared in the telescope. It works! And it was the first time I’d look in a telescope in about 20 years – I was both immensely excited and disappointed with myself for letting it happen. I’d always intended to replace the 5″ Newtonian I’d inherited when my great-uncle had died, and then subsequently sold as other life issues took priority (though I did enjoy watching Halley’s Comet through it during its last pass), but somehow that never happened. Still, all that’s under the bridge now…

Next was the Moon, almost directly overhead and half-full. When it came into view in the eyepiece I just gasped. I’d forgotten how beautiful and inspiring it was. It’d had that effect on me since I first looked into a telescope at age 6 or 7, and 30 years later it does exactly the same thing. I set the controller up to track it (which it did, but required frequent corrections because of my lack of setup) and gazed at it in open-mouthed awe for a good 30 minutes. I never get tired of it.

Feeling I had the solar system sorted, I thought I’d try out Orion as it has a number of stars and magnificent nebulae to choose from, all in one small chunk of the celestial sphere. However, as I’d not aligned the finder-scope or zeroed the tracking system, it made finding and keeping anything worthwhile quite hit-and-miss. So rather than spoil an otherwise great time, I swung it round onto Sirius (or Dog Star, due to its location in Canis Major) and enjoyed the light show of the brightest star in the night sky.

It was while out watching the sky that I saw the steady stream of visitors into my neighbour’s house, who holds a loud prayer evening every Thursday for the evangelical church of which he is a vocal, proselytising member, and was quite pleased that their comments and brief conversations with me all remained natural. Normally it goes very differently — though one did have to ask the other if he’d brought “his weapon” along, to which the other asked whether he should use the KJV or NRSV “weapon”…

So after 90 minutes of a marvellous stargazing experience, I packed up and brought everything back inside as it was quite cold, I don’t yet have a dew shield and the unit wasn’t setup correctly. Once I’ve aligned the finder-scope and learned how to correctly zero and adjust the controller, I’ll go back out and try again on Orion.

Orion and the Southern Cross were my favourite constellations as a child growing up in Australia, and Orion remains so today particularly because it’s visible in either hemisphere and remains a friend from a simpler time, reminding me of childhood wonder.

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In which we realise our insignificance

27 January 2009 Comments off

I felt compelled to share this fantastic video footage, posted to a friend’s blog. I’m not sure where the footage originates, but the music is clearly John Barry’s The Overture from The Black Hole, a film I enjoyed when I was young:

Our small world

[Edit: Normally I wouldn’t make this kind of edit, but Unreasonable Faith posted a similar video that just had to be shared]:

Star Size Comparison

I think it does they do a fantastic job of showing the relative sizes of planets within our solar system, our Sun, and the staggering sizes of nearby stars. The extra-solar stars pictured range in distance from almost 9 ly (Sirius or Alpha Canis Major, and is also the brightest star in the night sky) away to over 20,000 ly (the recently discovered V838 Monocerotis).

To put the video into context: if V354 Cephei were placed at the centre of our solar system, its radius would end somewhere between Jupiter and Saturn. It’s that big. And just look at the final comparison between our Sun and VY Canis Major, which is the largest star that we know about. If placed at the centre, its radius would reach to Saturn. This image puts the relative distances of the inner and Jovian planets into context (image from solcomhouse):

Visible Planet Orbits

Orbit of the inner and Jovian planets

It’s just mind-boggling how insignificant our own yellow dwarf Sun is in comparison to others in our own galaxy never mind a thought for our home, this pale blue dot hurtling through space around it.

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