Category Archives: Stars

RS Ophiuchi- a rare occasion

Posted on by September 6, 2021

Life seems to be chugging along when suddenly there’s a thermonuclear eruption somewhere far far away. By far away I mean 5000ly!
What’s happening there?

A white dwarf star and a red giant are orbiting one another and maybe too close for comfort. The white dwarf siphons off material from the red giant star and developes a dense atmosphere which consists mainly of hydrogen. The newly accreted atmosphere is thermally heated by the hot white dwarf.  With this extra mass, gravity increases and the white dwarf becomes compressed which causes it to ignite.
I’ve read that only 10 recurrent novae have been identified. So what I’m following here is quite rare
To get a visual comparison, I’ve been setting up missions to RS Ophiuchi on the same telescope at Slooh and more or less at the same time of night. Cloudy weather was persistent but just as well because the Moon might have been too bright and in close proximity on those cloudy nights.
I did not give up and last night, conditions were perfect and I got a beautiful follow-up image. There’s no doubt, RS Oph is dimming and will go into slumber mode again.

To do an accurate comparison, I have not processed or cropped these images.

Rho Cassiopeia is not just a star

Posted on by July 20, 2021

This is my first image of the huge yellow star, Rho Cassiopeia. When I do public outreach I usually don’t let the line of people grow to 50+ to look at just one star. “A star is just a star ” even through my telescope. We all love to show the ooh and wow objects. I’ve observed many double stars with my own telescope – they are really pretty. It was during Helen Avery’s Constellation Story Livecasts on Slooh that observing single stars became more and more appealing and having all the different telescopes available to do so, is just awesome. And I’ve seen that a star is NOT just a star.

 

Hind’s Crimson Star

Posted on by January 15, 2020

Lovejoy-chartI wondered what C/2014 Q2 Lovejoy would look like through a 400mm lens on a fixed tripod. Funny how I choose nights with a glorious gibbous Moon to become inspired! At first I was not impressed with the results. All the stars look like smarties with an orange one thrown in the box as well. Failed experiment but what intrigued me was why the camera had picked up that distinct orange star? Hot pixel?

“Pleased to meet you
Hope you guessed my name,
But what’s puzzling you
Is the nature of my game”

Hind’s Crimson Star ( R Lepus) is too faint to see with the eye alone but my camera and 400mm lens had picked up its colour – the colour of a dying star. Eventually, the star’s puffed up outer layers will all blow out into space, forming a glowing bubble.

Wikipedia: It is a carbon star which appears distinctly red. It is named after famous British astronomer J. R. Hind, who observed it in 1845. Its apparent magnitude varies from +5.5 to +11.7 with a period of 418–441 days; recent measurements give a period of 427.07 days. There may be a secondary period of 40 years.

Oh what Joy it was to find while chasing a comet through the sky.