Melbourne Partial Solar Eclipse, May 10th 2013

This morning was a partial solar eclipse in Melbourne. Back up where we saw the total solar eclipse last November they got an annular eclipse which would have been spectacular, but work is too frantic at the moment bringing up a new machine to even think about going up!

The first glimpse of it was from the train going into work with (of course) eclipse glasses (from Ice In Space) and by the time I got to Richmond I remembered I’d not taken a photo so had a go with my phone and the eclipse glasses and came up with this:

eclipse_train

My plan though was to go to the playing fields at the University of Melbourne where I’d learnt before (via Twitter) that there would be some astro folks. There was a small group of people there with a telescope set up to project onto a screen at the rear who were having fun trying to keep it on target as it wouldn’t lock into place. The nice thing about projections like this is that you get a nice big image, like this:

Melbourne Partial Solar Eclipse, 10th May 2013

I had a couple of left over eclipse glasses from the total eclipse so I passed them around and left them with them, they seemed to go down well!

Locking Down WordPress Admin and Login URLs

For those WordPress admins who are lucky enough to only access via certain defined IP addresses (IPv4 or IPv6) you can lock down access to the wp-admin and wp-login.php URLs in your Apache configuration with just:

<location /wp-admin/>
    Order deny,allow
    Deny from all
    Allow from 127.0.0.0/255.0.0.0 ::1/128 10.1.2.3/32 1234:5678:90ab:cdef::/64
</location>

<files wp-login.php>
    Order deny,allow
    Deny from all
    Allow from 127.0.0.0/255.0.0.0 ::1/128 10.1.2.3/32 1234:5678:90ab:cdef::/64
</files>

Hopefully that helps someone!

Astrophotography: Comets C/2011 PANSTARRS and C/2012 F6 Lemmon

Friday night I was at the Mount Burnett Observatory for the talk about the ASV’s New Astronomers Group (NAG), but we took a break from the talk shortly after sunset to look for the two comets in the southern sky that night, C/2011 PANSTARRS and C/2012 F6 Lemmon. It was a lovely clear night, though very windy, and we managed to see both of them. I’d brought my camera and tripod along and got these photographs:

Comet C/2011 PANSTARRS as seen from Mount Burnett Observatory

Comet C/2011 L4 PANSTARRS

Comet C/2011 L4 PANSTARRS

Comet C/2012 F6 Lemmon as seen from Mount Burnett Observatory

Comet C/2012 F6 Lemmon

…and this time with a passing aircraft…

Comet C/2012 F6 Lemmon with passing aircraft

Then on Saturday night I got this photo of PANSTARRS from Upper Ferntree Gully, visible as a naked eye object.

Comet C/2011 L4 PANSTARRS over Upper Ferntree Gully, VIC, Australia

Sadly PANSTARRS is heading off to the northern hemisphere so we may not get much more of it here in Australia.

In memoriam, Bob Samuel, 1925-2008

It’s been 5 years now Dad.

My father, Bob Samuel

My father was a sign writer and glass embosser by trade, working in the business started by his grandfather. He loved old mechanical things and one part of his work that gave him pride was hand painting museum acquisitions to their original standard. Here is a trailer for a steam road wagon originally operated by J.E. Thomas and Sons in Oswestry (and here’s a link to an advert for them, with a different livery).

J.E. Thomas and Sons, trailer for a steam road wagon

One summer holiday (1988 I think) I helped him paint three coal railway trucks for the Maritime and Industrial Museum in Cardiff (part of the National Museum at the time), the museum is long gone but they now seem to have moved up to Big Pit museum at Blaenavon).

Three Coal Trucks: Bute, Naval, Ocean

August 1993 “Preliminary Hardware Configuration for a Main Service Linux Machine”

From 1992 through to 1994 I was working at the Computer Unit at the University of Wales (well, wrangled an “Employment Training” position there on my own initiative) as a sysadmin and was running Linux on an IBM XT (from very dodgy memory). A friend of mine, Piercarlo Grandi, suggested to me (semi-seriously I suspect) that you could now build a large enough PC to support quite a number of users, and that the Computer Unit could use it as a central server (they were running DEC 5830s with Utrix), so I knocked up a text file and discussed it with my colleagues. They didn’t take it very seriously – little did any of suspect how much that would change.

Well tonight I indulged in a bit of computer archaeology and managed to get the data off my Amiga hard disk (from a GVP A530 expansion unit) and browsing around happpened to stumbleover that text file, dated 8:20pm on the 8th August 1993. It’s quite touchingly naive in places, and my numbers are pretty ropey.. :-)

Preliminary Hardware Configuration for a Main Service Linux Machine

Item                            Each    Number          Total

Case                             100    1                 100
Keyboard + Mouse                 100    1                 100
Floppies                         100    1                 100
DAT Drives                       750    4                3000
EISA SCSI Controllers            300    2                 600
Memory (Mb)                       25    256              6400
Pentium EISA Motherboard        1000    1                1000
3.5Gb SCSI-II Disks             1800    5                7000
Screen+SVGA Card                1000    1                1000
EISA Ethernet Card               200    2                 400
CD-ROM Drive                     300    1                 300

                                                        20000

Projected to be able to support between 200-400 users running Linux 0.99.p12
        (Alpha release kernel with patched IP - appears stable)


Notes:

(1) I've seen reports that the ethernet driver code may suffer from a
    memory leak, but I've not seen any evidence for this yet as my
    machine hasn't been turned on for a long enough period for it to
    cause any problems.

(2) As it is so new there is very little commercial software available
    for it, but there is a quite sizeable free software base with many
    of the GNU packages already ported for it, and this is generally of
    high quality.

(3) The Linux kernel is well thought out, and includes support for shared
    libraries (which Ultrix sadly never picked up) which significantly
    reduces the amount of memory applications need.

(4) A Linux box of the size proposed for the service machine has not
    been attempted yet (as far as I know), but ones of the size of the
    proposed testbed machine are already in usage on the Internet. I
    believe that Linux can handle this scaling up with no problem.

(5) There are apparently companies within the UK who sell support services
    for Linux, I will investigate further.

(6) There is already a large amount of Linux expertise on the Internet,
    including the comp.os.linux newsgroup, the linux-activists mailing
    list and even an IRC channel dedicated to Linux users.

This post is dedicated to Rob Ash, my then boss, who took a chance taking me on after my time as a student mucking around on computers when I was meant to be doing my Physics degree, and who was a great mentor for me.

Mount Burnett Observatory (@MBObservatory) now on Twitter

For almost a year now I’ve been a member of the Mount Burnett Observatory, a community project at the old Monash University astronomical observatory at Mount Burnett in the Dandenong Ranges. It’s great fun with both the original 18″ telescope and new 6″ and 8″ Dobsonian telescopes (some thoughtfully sponsored by the Bendigo Bank for education and outreach purposes).

It’s had a Facebook presence for a while, but nothing on Twitter, so after speaking to the webmaster and the president I’ve now set up a Twitter presence as @MBObservatory.

So if you’re into astronomy and around Melbourne (especially the south-eastern suburbs, though we do have people travelling in from quite a way) and use Twitter please do follow us!


Happy Newtonmass All

With just one sleep left to the annual celebration of Sir Isaac Newtons birth on the 25th December I’d like to take the opportunity to wish everyone a very Happy Newtonmas and may gravity not weigh you down too much in the coming new year. :-)

Summer sunset through the grass

This photo was taken this evening at Cardinia of the sun setting through grass, the choice of where the real horizontal lies is yours.

Total solar eclipse in far north Queensland, 14th Nov 2012

Donna and I travelled up to Trinity Beach, about 20 minutes north of Cairns, for a holiday with a total solar eclipse in the middle of it.

We were really lucky as firstly we nearly didn’t make it up there at all as Jetstar cancelled our flight up and couldn’t get us another seat until Wednesday which would mean missing the eclipse and losing the accomodation we’d booked. Fortunately we were able to get a flight up with Virgin instead on the same day as our cancelled one, but it cost more than the refund from Jetstar. Then there was the weather; we arrived on a nice sunny Sunday and it looked quite promising, but Monday and Tuesday were both pretty cloudy and wet at times, so it wasn’t looking good.

Wednesday morning rolled around and we were up early (with three different alarms, just in case) and it was clearer than the previous days, but still plenty of broken cloud around.

First Contact, Obscured By Clouds #1
First Contact, Obscured By Clouds #2

There were probably a few thousand people around on Trinity Beach…

An audience for an eclipse, Trinity Beach, QLD

…who watched the partial phases nervously, but with growing excitement, through the cloud.

Peek-a-boo #1
Peek-a-boo #2

We were getting close to totality, but a large cloud was looming, and we wondered if we might miss the total eclipse phase!

Audience anticipation - eclipse or cloud?

Our luck held though, and we managed to see totality through broken cloud. :-)

Totality through the cloud!

Of course, after third contact and the end of totality the cloud started to clear and we had a good view for once.

After third contact - in a clear sky

The folks down in Cairns (including my friend Ian Grant from the Bureau of Meterology who lent me a 1976 solar eclipse filter) were not so lucky, they saw the partial phases but missed totality due to cloud. An American in front of him told him that was the third time in a row it had happened to him!

Video of Total Solar Eclipse, Trinity Beach, QLD – 2012/11/14

This is my attempt to capture the view of the total solar eclipse as seen from Trinity Beach in Queensland, Australia with my D90 DSLR, uploaded to YouTube with a CC-BY license.

Our tripod wasn’t usable unfortunately so this was taken resting on my knee and, as you’ll see, I got distracted by totality so it wandered off target a couple of times. I stopped filming so I could try and take a still photo as it looked like we were about to get clouded out, hence stopping short. We did manage to see the diamond ring just after though!

Want to help with the Linux kernel?

Greg Kroah-Hartman, the maintainer of the stable releases of the Linux kernel (the point releases after a 3.x release, e.g. 3.6.5, etc) is looking for help for about 6 months as he’s getting overwhelmed.

I’m looking for someone to help me out with the stable Linux kernel release process. Right now I’m drowning in trees and patches, and could use some one to help me sanity-check the releases I’m doing.

Specifically, I’m looking for someone to help with:

  • test boot the -rc stable kernels to make sure I didn’t do anything foolish.
  • dig through the Linux kernel distro trees and send me the git commit ids, or the backported patches, of things they are shipping that are not in the stable and longterm kernel releases.
  • do code review of the patches going into the stable releases.

If you can help out with this, I’d really appreciate it.

You’ll need to show you’ve had kernel patches accepted, are running the latest stable release candidate kernel and can find distro patches (details at his website). You’ve got until November 7th to apply!