Saturday, January 31, 2009
Venus and the Moon in Daylight
I got a chance at around 4:00 pm on the way to a meeting. I looked a bit strange, standing hand on door staring intently at the sky as I paused on my way in. I saw the Moon relatively easily, but I was confused for a moment as I couldn't see Venus. I then realised I was looking too far left, and it popped out for me. I was able to show Venus to another meeting member before going inside (real footpath astronomy).
Back home (late, because of aforesaid meeting), I took this shot at around 7:00 pm with my Canon IXUS at 3x zoom (still an hour and a half before Sunset, click on the image to enlarge to see Venus clearer).
Shortly after, swimming with SmallestOne ("..heres a ball of coke, you can lick it, it's syrup, it's smelly because todays a smelly day..") I could see Venus peeking out behind the trees before sunset.
This is a more traditional tewilight image of Venus and the Moon, showing the earthlight. Nice evening, pitty about the scorching tempratures.
Friday, January 30, 2009
Carnival of Space #87 is here.
Labels: carnival of space
Thursday, January 29, 2009
Using Venus to Find The Moon
Anyway, while listening I was idly scanning the sky for a glimpse of the Moon (or the flying pigs we had to burn), ready for tomorrows Daylight Venus and Moon apparition, but I couldn't see it. Suddenly I saw Venus, clear as a bell (or rather a very bright diamond) just hovering in the sky. Working backwards from Venus, I could find the thin crescent moon floating palely in the sky. Ironic, as this morning I had just given instructions to use the Moon to find Venus.
Anyway, tomorrow the Moon will be a thicker, more obvious crescent in a darker part of the sky, and much more obvious to see, but still, it was funny.
Venus in Daylight 30 January 2009
Venus is bright enough to be seen in daylight, but can be hard to find. On Friday 30 January Venus is just two fingerwidths above the crescent Moon making it much easier to find.
You should wait until the late afternoon, when Venus and the Moon are reasonably high. Make sure the Sun is hidden behind a building or wall or something substantial, so you cannot accidentally damage your eyesight.
The Moon will be around 44 degrees north from the Sun (around
Later in the evening, the pairing of the crescent moon and Venus will be quite beautiful.
Wednesday, January 28, 2009
Mobile Phone Solar Eclipse
They came out really well considering. I'm using a fairly standard Sony-Ericcson with a 1 megapixel internal camera just held up to the lens of a 4" unguided Newtonian reflector.
Despite this the images are fairly crisp, limited mostly by the atmospheric roiling messing up the image of the Sun. Without any Sunspots, it's hard to say exactly how focussed the image was, but it certainly shows the eclipse sequence well. The last image shows the Sun as it disappears behind a rooftop, still partially eclipsed.
This goes to show that you can take decent astronomical images without fancy equipment. Those of you with a simple refractor or refelector sitting in a cupboard because "it's not good enough", dig it out and have another look.
Tuesday, January 27, 2009
Reflections of Venus
Here is my image of Venus reflecting off the sea (as always click to enlarge). The track of Venus was quite clear, but unlike last night there was no fireworks to go with it. The image was taken with my Canon IXUS at 9:40 pm ACDST (about 1 hour 15 minutes after sunset), from a height of about 10 meters looking down to the sea. Exposure time was 10 second at ISO 400 (Focal lenght 6.2 mm apature 2.8). Venus is at near maximum brightness (Magnitude -4.5), and at a sufficent height above the sea for it to remain visible after nautical twighligh a a decent distance above the sea, but not too high (10 degrees in this case). In the next few days the waxing Moon will drwon out Venus's refelection so try and see it if you can.
Other people have done better photos, see this one here.
Monday, January 26, 2009
Not Really Live Blogging The Australia Day Eclipse
6:30 pm (ACDST): Get scope set up. I am using the 4" scope, rather than the 8", because my only solar filter is for the 4" tube. Decide to not set up a projection scope due to the shallowness of the eclipse, and the fact that so much else is going on.
7:05 pm: Get out late due to dinner, faf around trying to set the scope lined up with the Sun (can't use the finder scope, as this will burn my eye out), fiddle scope around so that it's shadow is minimised, this should have it pointing directly at the Sun, or would have if I hadn't had the scope aligned pointing directly at a large wall (slaps forehead). Realign scope, see large chip taken out of Sun. Take images with Canon IXUS and mobile phone directly though lens.
7:20 pm: Chunk of Sun missing larger, and sliding around edge of Sun. The Sun's disk is spotless, making the view even more stark. Take some more shots. Boys come out to have a look at the chip out of the Sun. Then back in to deal with SmallestOnes School orientation report.
7:29 pm: Eclipse maximum, despite being at only 10% covered, the dark bite form the Sun looks impressive. MiddleOne takes another look. The edge of the Sun roils in the heat haze as it come closer to the horizon.
7:40 pm: Moons edge growing smaller and moving "up" the Sun's disk. Relocate the scope to avoid Sun going down behind house.
7:45 pm: Sun disappears behind roofs, still notched with the receding Moon.
That was a pretty good way to spend the afternoon of Australia Day. Despite being a fairly weak partial eclipse, it still looked amazing! Folks up north and to the west will have had much better views. To round a great day off, as I snuck out from the washing up for a quick gander at the Australia Day fireworks, I could see the reflection of Venus in the sea, a rather rare sight. Fantastic!
Saturday, January 24, 2009
Australia Day Partial Solar Eclipse.
For most of Australia, the eclipse is rubbish (just around 1% covered in Melbourne and Canberra, 6% In Adelaide), The best views are from the Northern Territory and an Western Australia. This link will give Australians local times for eclipse start, mid eclipse and eclipse end, as well as important safety information and safe solar projection techniques. NEVER LOOK DIRECTLY AT THE SUN, Okay.
Other Southern Hemisphereians can check eclipse times in Universal Time here.
Monday, January 19, 2009
Talk amongst yourselves (one more time)
Sunday, January 18, 2009
What Meteor Showers to Watch
One way to get around the Southern Hemisphere/Moon phase problem is to use NASA's fluxtimator, which will estimate the number of meteors you will see for a given shower at your location. However, it seems to be broken for the 2009 Leonids (other showers work well though, try the 4 Geminid entry for the night of December 13-14).
Saturday, January 17, 2009
A Full Moon Rises
He took the photo with his Canon S2IS set at 50 ASA on F5 for 0.4 sec. Some post processing was done to the photo to bring out details.
As well, you might like to follow this link from Stephen Skyes to his image, taken with a Nikon D40 (There's lots of other cool images there too).
Southern Skywatch January 2009 edition is now up!
There is Venus near the Moon, Saturn rising, Algol blinking and a partial solar eclipse for Australia Day.
Labels: southern skywatch
Friday, January 16, 2009
Much Ado About Methane (Is there life on Mars?)
NASA has a headline saying "Mars is Not a Dead Planet". The reason for this headline is the discovery of appreciable amounts of Methane on Mars. What's the fuss about a gas we usually associate with bottom burps from cows? Will precisely because they are associated with bottom burps from cows, due to methane generating bacteria. Bacteria are one way the methane on Mars could have been produced, it's seasonally produced and found in special hot spots. This could be an indicator that bacteria deep in the Martian crust are churning way at whatever it is bacteria do a kilometer of so underground.
Or it could be more prosaically due to volcanic activity, but Mars is supposed to be geologically pretty inactive. Either way, the prospect that Mars is either much more geologically active than we thought, or harbouring deep seated microbes, make this red world a heck of a lot more interesting.
The NASA story is here, and more images and animations here. Emily Lakdawallah has a great post on the whole issue. Here is an article from Astrobiology Magazine, one from New Scientist and finally one from Science.
Thursday, January 15, 2009
The Big Full Moon of Saturday 11 January 2009
Still, it looked gorgeous! And the light was bright enough to read a magazine by!
Hope you all got to see it!
Tuesday, January 13, 2009
Carnival of Space #86 is here.
Labels: carnival of space
The Things You See ...
Jon Jenkins writes a letter...
Jon Jenkins turned up the the comments to Deltoids thread on this subject (his comments start here). Sadly, he completely missed the point (and I missed the chance to make a useful contribution).
*Yeah, he's fed up with being called names. You should see what I have been called by creationists, HIV/AIDS deniers and various other anti-rationalists. I think I win the title for "most swear words used as an adjective before my name". Somethines I get grumpy, but I have never used untruths or accused honest people of fraud to try and make my case against the anti-rationalists.
Friday, January 09, 2009
Biggest Full Moon this Sunday Night (11 January 2008)
What's Up with Polynomial Fits (yes, it has astronomy content)
The raw data, on casual observation, is a bit noisy, but appears to plateau then fall in the final observations.
The polynomial fit is the green curvy line (I've used a 5th order fit here, as the graph in the Jon Jenkins article used a 5th order polynomial). It sort of wobbles up and down a bit, then does a spectacular dive at the end, just like in the Jenkins graph).
A pretty good estimation of the trend eh? No. The data is actually a continuously increasing line to which I have added noise. The scale of the graph and the range of noise variation was chosen to match the UAH tropospheric temperature data. The "trend" given by the polynomial is dead wrong. The linear fit (black straight line) recovers the real line out of the noise pretty well.
The polynomial fit is quite sensitive to the final data points in a series, it just needs a bit of noise to send the curve flailing around like a snapped hawser. And climate data is very noisy, that's why scientists study long term trends, where the noise can be averaged out. Also, as we are coming off a La Nina event, we expect there to be a drop in global temperatures, it's what La Ninas do. To use a polynomial fit of truncated data when you know there is more data and you know we are coming out of a La Nina event is either sheer stupidity or culpable fraud.
This is why you don't use polynomials fits in these circumstances, they will either be misleading or completely wrong. Have a look at the second graph, it a graph of stellar intensity. The black line is the polynomial fit. Now, if someone told you that the polynomial "trend" meant that the star would soon fade away, would you accept that?
Espeically if you knew it was a truncated section of the intensity graph of Algol? That's the sort of thing Jenkins is trying to get away with.
* They are at it again today, with a headline "Obesity Epidemic a Myth", which grossly distorts the actual science. I'll rant about that later (our kids are nolonger getting exponentially fatter, they are still some of the fattest kids in the world though).
Thursday, January 08, 2009
The Anniversary of Galileo's Death
Wednesday, January 07, 2009
The Australians War on Science Keeps on Rolling.
Now, Jenkins is an Adjunct Professor of Virology, specialising in computer modelling. Why is it that the Australian never gets actual climate scientists to comment?
Heck, I'm a Senior Lecturer in Pharmacology, and I do a lot of computer modelling (okay, so its molecular modelling), why do they never invite me to comment? (insert pout here). Professor Jenkins opens with a standard litany of denialist taking points, satellites more reliable than ground based temperature recording (it's not), and that the "hockey stick" graph is fraudulent (it isn't). Professor Jenkins should be a little more careful with his accusation of fraud though. In his article he says "They [the satellite measurements] show minuscule warming, all in the northern hemisphere, which not only stopped in 2000 but had completely reversed by 2008 (see graph)."
Now the graph is not in the online version so I have taken the liberty of reproducing the graph under fair comment rules (its the graph at the top, click on the image to enlarge it, the Australian seems to have pinched it anyway). The data is from the UAH MSU global monthly lower troposphere temperature data set. You can down load it yourself and graph it. Just like I did, the result is in the bottom image (again, click on the image to enlarge it). You can compare my graph with the image accompanying Professor Jenkins article.
One of the first things you can see is that the Australian graph finishes just a wee bit early. Now I don't know if Professor Jenkins prepared the graph (it appears to be redrawn from an illustration in a US newspaper article published in October, whoever did the redrawing was being a bit naughty in producing misleading attributions), but he references it, and should have checked it for accuracy and completeness. Because the data set he uses finished in August, missing out the September, October and November data. If you include that data, the temperature anomaly bounces right back, regaining the supposed "wiped out" warming. Now the November data were there way back in December, so there is no excuse for showing a truncated graph. Professor Jenkins may not have produced this misleading graph, but he should have checked it (finding the original data wasn't hard).
The "trendline" shown in the Australians graph isn't strictly speaking a trendline, it's just a high order polynomial fit, which will generate a nice looking smooth line but will not actually reflect the trend of the underlying data. It's rather naughty to use polynomial fits in these sorts of situations. Again, Professor Jenkins appears not to have produced the fit, but he should have known immediately that this sort of polynomial fit is inappropriate. In my graph I show both a linear fit (black line) and a rolling 3 year average fit (red line). Both more appropriate models for this sort of noisy data. As you can see, global warming has not gone away. As well the UAH data agrees with the other satellite data and the two land based data systems in showing that warming hasn't stopped. Indeed the UAH data shows a warming of 0.14 degrees C per decade, comparable to the 0.16 degrees per decade found by surface stations (the RSS satellite data finds warming of 0.18 degrees C).
The dip in 2008 was caused by a La Nina event, and is not surprising at all. See also here and here for more discussion of 2008 temperature trends.
Professor Jenkins goes on at length about a whole range of other issues in climate change, but it won't surprise you that he is wrong about them too (eg Volcanoes as CO2 generators). Ironically, this piece was published the day before the Quadrant Hoax hit the Australian headlines. You think the editors might have done a little fact checking too.
But, Professor Jenkins the bottom line is you shouldn't be too quick to accuse scientists of fraud when you can't be bothered to check out the datasets and draw your own graphs (and do your own modelling).
UPDATE: Tim Lambert blogs the Jenkins article here. Also, Jenkins has in his article the statement "Science is only about certainty and facts." It is not, it is about inference to the best explanation. But again, the irony of bringing up certainty when Jenkins hasn't done his fact checking is palpable.
Labels: global warming sillyness
Tuesday, January 06, 2009
International Year Of Astronomy Downunder.
In Australia the local organising website is http://www.astronomy2009.org.au/, there is a calendar of events colour coded by state (Western Australia has lots of activities but currently are keeping them in a WA-specific calendar on the Scitech website, and not entering them into the general IYA website. Tasmania has events in the planning but for most them the dates are not yet pinned down. South Australia is planning activities which will hopefully soon up at the Astronomical Society of South Australia website). You may like to organise your own event for your school or comunity, or find out what your local astronomical society is doing.
One of the big events will be the 100 Hours of Astronomy on April 2-5, a massive public star party. Keep an eye on this site for further developments. There is also the Cosmic Diary, a weblog with contributions from astronomy enthusiasts, professional and amateur, around the world and 365 days of Astronomy, a daily podcast that you could contribute to.
So, there is lots happening in the International Year of Astronomy for Australians (and New Zealanders and other Southern Hemisphereians), so get involved and look up!
Labels: International Year of Astronomy
Monday, January 05, 2009
Mars Rovers celebrate 5 years on Mars
Comet Al tells the tale of P/2008 X4 Christensen's recovery.
UPDATE: See the Bad Astronomers post on Perihelion, especially the comments where there is a nice table of the names for Perihelion for all the planets.
Sunday, January 04, 2009
Venus in the Daylight, on New years Eve
An hour before Sunset, actually (you need to click on the image and get an enlarged version to see Venus clearly).
Now, as regular readers of this blog know, I'm obsessed with seeing Venus in the daytime.
While I've been quite good at catching Venus by eye, getting images has been much harder, and using my old Olympus Mu 300, the best images I could get were around 15 minutes before Sunset. This image is taken an hour before Sunset using my newish Canon IXUS 9015, ISO 100, 1/400 second shutter speed and F 18.6 with superfine resolution. There has been no post processing except for cropping and typing the Venus caption in.
I used the Moon to locate Venus, and a corner of the house and pergola to shut out the Sun and frame the Moon Venus combination.
As I've noted before, it always seems easier to locate Venus (or Jupiter) if there is a handy foreground object nearby. This is possibly due to the contrast making the eye "floaters" less obvious and making Venus more obvious. Using a wall/roof combination really helped to make Venus obvious, and also framed the image, making them easier to find while hunting in the full scale image.
Your next good opportunity to see Venus in the daylight is on January 30th, when the Moon is 45 degrees from the Sun, magnitude -4.5 and only 2 degrees (roughly two fingerwiths) above the 15% illuminated crescent Moon. Look for the thin crescent Moon, and Venus should be visible as a bright dot just above it. It's best to look in the afternoon when the Sun is low and the sky is less bright. Make sure the Sun is hidden behind something solid like a building or a wall when you are looking for Venus, not trees or your hand. Exposing your eyes directly to the glare of the Sun can be very dangerous and you could potetially lose your sight.
If you can't wait for 30th January, locate Venus around half an hour before Sunset, and find a conveniet marker (a tree, a teephone pole or something like that) close by to Venus from a fixed postion in your yard. Note the relative position of Venus and features on the marker. Next day, go to your viewing position about 5 minutes after Sunset and note Venus's location. The next day, look 5 minutes before Sunset and note the location. And so on until you can see Venus well before Sunset. Do remember to be very careful not to look directly at the Sun when doing all of this. Chose your viewing location so that the Sun will be hidden well behind some solid object at all of your projected viewing times.
Good Luck Venus hunting!
Saturday, January 03, 2009
The Moon and Venus on New Years Eve
Carnival of Space #85 is here.
Labels: carnival of space
Thursday, January 01, 2009
Happy New Year 2009!