Thursday, December 22, 2011

Winter Solstice 2011

Reflected on my post about the winter solstice of 2007, especially the part on the relevance of marking this occasion in the tropics.



Well, I'm in the thick of winter now at 31 degrees north of the Equator. It was cold today and the sun set around 4.30pm.

I'm looking forward to longer days back in Singapore. And of course when my family comes back to Shanghai towards the end of January. Most of all, I'm looking forward to joining my family. I imagine the mandarins that were sent to faraway posts, returning once a year for the winter break to join their families. Suddenly the term "year-end block leave" takes on a significance it never had for me.

Let me wish one and all a happy reunion time this winter solstice as you go home to loved ones.

Wednesday, December 21, 2011

Kemble's Cascade

This is the second of two groups of stars with interesting patterns I saw around the winter solstice. Had to wear three layers of pants, four layers of tops, a scarf, a cap and ear muffs to fend off the sub-zero temperature.

This group of stars is known as Kemble's Cascade, named after a Canadian friar from Saskatchewan. More information from NASA here. It's really quite pretty through the telescope, looking like stars tumbling down a stream.

A sketch on GIMP 2 (note that the entire chain took up at roughly 3 fields of view through my eyepiece):



Kemble's Cascade includes an open star cluster designated NGC 1502. Although with the limited resolving power of my telescope I could only make it out as a rather bright star (top right of the sketch).

A star cluster is a group of stars that are bound together by gravity. You might say that the attraction is mutual.

On the other hand, the entire chain of stars along the cascade is not gravitationally-bound. They look like they form a chain but in actual fact are probably millions of light years away from one another. Such fortuitous associations are known as asterisms.

To put it another way, you stand in front of a tree and see the moon above your neighbour's satellite dish across the street. The moon may look like it's hovering 2 feet above the dish but you know they're a few million miles apart.

It's all about perspective.

To locate Kemble's Cascade, see the sketch below:



First find Mirphak, our star in Perseus featured in my previous post. Then look for the M-shaped constellation Cassiopeia. Kemble's Cascade roughly forms a right angle triangle with Mirphak and Segin, the star making the right foot of the M.

Tuesday, December 20, 2011

The alpha Persei association

Had a very clear sky tonight and decided to do some casual observation before flying back to Singapore.

Looking north, almost at the zenith and in line with the meridian was the constellation Perseus. Through a 70mm refractor at 20x I was able to make out an interesting chain of stars around Mirphak or alpha Persei, the lead star of the constellation. It's an interesting chain snaking, as if dancing, around Mirphak.

I made a sketch on GIMP 2 here:


Although skies were clear, light pollution was really bad. Bortle Scale of 9, bright inner-city lights with Hongqiao airport less than 5km away and its runway lights blasting up to the north of where I was. There're definitely more stars in this chain and I could only catch a hint of them with averted vision. The Pole Star was barely visible.

More on star associations and this particular one here:

http://www.cloudynights.com/item.php?item_id=2565

More on Perseus the next time.

One-year hiatus

Shanghai, clear skies, 3 to 11 degrees Celsius.

Looking at my long-ago posts I'm quite taken by how much things have changed. I wonder if it's still worth keeping up this blog. Everyone seems to have moved on to Facebook and/or Twitter. Perhaps only Wifey and a former student of mine who's in Boston now still drop by occasionally.

I'll keep this blog perhaps as something to leave to my children.

Went out to the cold tonight to look at the stars. They remind me that there are bigger things in life than work and petty affairs of those around me. They speak to me of the frailty of Man in comparison to everything that's out there. They have been shining since before I was born and they will continue to shine after I turn to dust if the Second Coming doesn't happen soon.

Mostly the stars tell me to treasure the moments I have with my family. I miss them (family, not the stars) badly for the past two months since Wifey went back to Singapore to prepare the arrival of our 4th.

My family, my only treasure here.