Archive for the ‘Uncategorized’ Category

Another early morning rainbow

February 23, 2016

About to ride to the bus station this morning; greeted by another nice rainbow:

 

Brought to us by the laws of physics. No pot of gold evident. Pity.

April 4th 2015 Total Lunar Eclipse from Adelaide

April 5, 2015

We were mostly clouded out here in suburban Klemzig. I took images during small breaks in the cloud. This one was taken at 22:11 ACDT, 16 minutes before the start of totality.

IMG_0018-cropped-75

Canon 1100D, ISO 800 for 3 seconds at prime focus of Meade LX-90 8″ SCT

Unfortunately totality was completely clouded out here. There are plenty of better images by others, e.g. by Jarrod Koh and Paul Haese.

My first DSLR photometry observation

February 3, 2015

After more than 5 months of gearing up to do DSLR photometry and two AAVSO CHOICE courses later, I submitted my first DSLR photometry observation yesterday: R Car, magnitude 5.054 with an error of 0.025.

First Submission

With a visual observation, the best I could have said that it was magnitude 5.1 with an error of a tenth of a magnitude. With DSLR photometry I can get down to a hundredth of a magnitude. A CCD could do better (a thousandth) but for ten times the cost, or more.

Yet another step in the evolution of my hobby. Thanks to Mark Blackford for sharing his considerable experience.

 

 

 

Total Lunar Eclipse!

October 8, 2014

Despite a fairly cloudy sky here in Adelaide, it gradually cleared to provide a nice view of tonight’s total lunar eclipse.

I took more than 150 images with my recently purchased Canon 1100D DSLR, a few of these from a tripod with a 100mm f2.0 lens. Most, like this one were taken with the 1100D through my LX-90 8″ SCT scope at prime focus.

IMG_00373 second exposure, ISO 1600 at 20:46 ACDT

I’ll post more when I’ve had the chance to take a closer look.

See IceInSpace for some more of my images.

Brief glimpses of Nova Cen 2013 (now V1369 Cen) through cloud

December 5, 2013

AAVSO visual observer Michael Linnolt had this to say on an AAVSO forum a short time ago:

Even here in the southernmost tip of Hawaii (19N) This nova rises too late in morning twilight to be readily visible. I suppose from the summit of Mauna Kea, with the perfect horizon and clarity above the clouds, it may be possible, but I’m not going to drive all the way up there just for this (2.5 hrs by road and 14000ft high!)

That drive to Mauna Kea would be a bit much. At least all I have to do is step out into my backyard. ;)

But then there are clouds to contend with…

Adelaide_South_Dec_6_dawn

That doesn’t look so bad now does it? Hmm…

I caught brief, tantalising glimpses of V1369 Cen near dawn (around 5:05 am Adelaide time and for 20 minutes or so thereafter) through thinning cloud with 7×50 binoculars.

It was, of course, clear soon after sunrise…

Adelaide_South_Dec_6_after_sunrise

The nova seemed brighter than yesterday morning but I cannot quantify that since I couldn’t see more than one comparison star and the nova for long enough to be able to make an estimate. I briefly spotted bet Mus and the nova within a few seconds of each other and the nova was certainly less than beta Mus (<3.045). So, all I can declare is that V1369 Cen was brighter than my Dec 4 observation (which was >4.33) and fainter than magnitude 3.045. 

Jonathon Powles and another observer in Canberra estimated V1369 Cen at around magnitude 3.5 this morning.

I spent time last night looking for additional sufficiently bright comparison stars and talking with Sebastian Otero about this since we seem to have run out of them! VSP has some limits in that regard.

nova_cen_2013_comp_stars1

The screenshot above shows some of the comparison stars as circled (from Sky Safari on an iPad).

The forecast for tomorrow is less dismal, so I’ll try again then.

First glimpse of Nova Centauri 2013!

December 4, 2013

I had my first glimpse of Nova Centauri 2013 (PNV J13544700-5909080) at 5:14 am local (Adelaide) time today, near dawn, as the sky was starting to turn blue.

All I can really say from that hurried observation, given the finder chart I was using, is that it was brighter than the magnitude 4.33 comparison star (JD 2456631.28102, >4.33). I used  7×50 binoculars.

What an awesome sight!

Tomorrow morning I need to be better prepared by:

  1. being outside about 45 mins earlier;
  2. using additional comparison stars from the AAVSO alert notice.

Cairns 2012

November 25, 2012

I was in Cairns for the 2012 total solar eclipse on November 14th. I arrived late on the 12th and flew home on the morning of the 15th. Leading up to the 14th, I stayed with AAVSO staff member and friend, Sara Beck, her husband John and their eclipse chasing friends.

We were located at Clifton Beach about 30 minutes north of Cairns.

Sara and John, both very keen eclipse chasers, decided to go inland for the best view possible. Being less of diehard, I stayed put and still had an excellent view from the beach. My first 2 minutes of totality at around 6:38am is something I won’t forget in a hurry.

What stays with me is the simultaneous corona and pink/orange prominences that became obvious to the unaided eye as soon as totality began, at 6 o’clock on the disk, later at around 10 o’clock and elsewhere. Rob Kaufman’s image below shows prominences even during the diamond ring effect. Rob is another AAVSO member, from Bright, Victoria.

Image of 2012 Cairns total solar eclipse by Rob Kaufman

The quality of the light leading up to totality was surreal.

The size of the disk took me by surprise; I thought it would appear smaller. I assume that the apparently large disk size was an elevation effect, the same one that gives the illusion that the moon is larger when it appears on the horizon than when it is closer to zenith.

The cloud was a bit of a worry leading up to totality, but it worked out well in the end. The disk went into cloud a few seconds before totality ended but it was visible most of the time.

The other motivation for making the trip was to meet Sara Beck, my VStar collaborator at AAVSO since mid-2009. It was great to meet up with her finally. We had some good chats.

On the last night I had a beer with AAVSO Director, Arne Henden, and Andrew Pearce, a Long Period Variable observer from WA. We had an enjoyable conversation about the eclipse, visual variable estimates, future directions for VStar and other AAVSO Java applications.

I had a good look around Cairns while there. It’s a very tourist-oriented place, but nice enough. Next time I get up that way I’ll be sure to spend some time out on the reef.

I cannot claim that witnessing this event has filled me with a sudden compulsion to chase every total solar eclipse I can get to, but my wife Karen and I are already talking about the next one visible from Australia, in 2023 from Exmouth in remote WA.

I can honestly say that it was an awesome spectacle, different to any other astronomical event I’ve witnessed. But that’s the cool thing about astronomy: the diversity of observable phenomena.

50th Anniversary of Algol 60

August 3, 2010

Last week I gave a talk about Algol 60’s 50th anniversary to the South Australian Branch of the Australian Computer Society.

Leading up to the talk, I found it difficult to stop reading. There’s so much historical material available, especially online, not to mention the several programming language related books on my bookshelf that had not been consulted for several years.

Anyway, here are the slides as pptx, ppt, and PDF.