Friday, 27 October 2017

CaK Full Disk 27th October

Three observations of our star this month seems like a record based on the poor weather that has hampered observations for some time now, but, this morning it was certainly nice to first of all have clear skies and secondly be able to observe the sun.  Things are quiet currently as we descend ever closer to the bowels of solar minimum, but there are still the decaying active regions with small spots and associated plage of the active regions that have graced us for a third time around the sun.  The full disk was taken with the 40mm scope at ~560mm focal length with the home brew CaK filter and the PGR Chameleon 3 camera.  Not sure these spots will survive a 4th rotation but i'm confident we will see the plage again even if it is somewhat diminished than it is now.

AR12685 & AR12686 in Calcium Light - 27th October

A quick close up this morning of this pair of decaying active regions, now on their 3rd rotation of our star, not much other than a couple of dead spots and relic plage regions are all that are left now.  Pleased this image came out at all as was imaging with the 40mm scope somewhere up around 800mm focal length with the home brew CaK filter and PGR CH3 on an unguided camera tripod, quickly grabbing some frames to stack as the image raced across the field of view!

Wednesday, 25 October 2017

CaK Full Disk - 25th October

A sunny start to the day here in Anglesey, but I could see the next bands of clouds heading in from the south on Sat24 so was keen to try and get an image of our star in the frugal opportunities that have been presenting themselves in the second half of 2017.  I used the 40mm scope at 560mm focal length un-driven on a camera tripod with the PGR Chameleon 3 camera.  Given how this came out i'm pleased with the result, especially now as I type this a mere few hours after imaging the clouds have returned.  Taken with the home brew CaK filter.

Monday, 16 October 2017

A Deep Orange Sun, An Ex-Hurricane and Saharan Dust - 16th October

A curious and unique set of meteorological conditions gave a view of the sun today not often seen here in the United Kingdom.  Ex Hurricane 'Ophelia' was tracking northward in the Eastern Atlantic and due to make landfall on the southern coast of Ireland first thing on monday morning.   This had the effect of drawing up a warm source of tropical air from the Sahara Desert from North Africa.  This had been forecast for a couple of days over the weekend as temperatures in the UK rose to 25 celcius, some 10 celcius above the norm for this time of year.  Indeed on the sunday night a faint pinky sunset indicative of atmospheric particles scattering the longer wavelength red light.  The chart on the left shows the red line is the source of Saharan dust, whereas the blue and green plots have their origins from the mid Atlantic.  The red plot represents an air source within 500m of the surface whereas the green and blue plots air is some several thousand metres above the surface.  The plot below from the University of Greece shows the distribution of Saharan dust across Europe.  
The tongue of dust over the UK is been drawn up from ex Hurricane Ophelia drawing up the warm air from the south into it's cyclonic system.  The sky over Brierley Hill took on a peculiar Martian pinky tinge, looking very unusual, with the sun taking on a bright orange colour as the dust scattered red light in the atmosphere.  As the air source changed the sky and suns curious look changed back to normal almost instantly, and it's low height above the ground is shown by the pinky brown band on the horizon in the picture below.  If it was higher it would be more diffuse.  

Sunday, 8 October 2017

Ghostly Clouds of Plasma - 8th October

The sun at first sight seemed deathly quiet today when I looked on GONG before going out to observe, but as is usually the case with our star it is just a case of looking in the right place and the right wavelength.  The air was surprisingly clear so I knew despite poor seeing looking in calcium wavelengths was going to be worthwhile.  Only the day before the active regions that had survived 2 rotations, producing the largest flares of this solar cycle rotated out of view over the limb.  However such large sunspots like that don't just effects in the photosphere, they are active in the chromosphere and above.  Today was a great example of this, despite the active regions being over the other side of the limb, the clouds of plasma that sit tens of thousands of kilometres above them were still visible silhouetted against the background of space.  The thin solar chromosphere, some 3000-5000km thick is visible with it's spicules on the limb. This shot was taken with the 40mm scope at 560mm focal length with the PGR Chameleon 3 camera and homebrew CaK filter.

CaK Full Disk - 8th October

It's been 7 weeks, not counting the eclipse, since i've been able to observe the sun.  Sunday dawned with some gaps in the clouds that were floating about, the sun is much lower in the sky, so waiting for it to clear the buildings I set up and went out to observe.  I knew that with so many surrounding clouds the seeing was going to be less than ideal, and indeed this was the case, so decided on the 40mm scope with the homebrew CaK filter to get an overview of the disk.  I knew it was going to be pretty blank with only a few regions of plage from relic active regions, but, where the large grouping on the western limb has passed over it was possible to see some towering clouds of plasma high above the active regions.  Click on the image for the full size view to get more detail.

Saturday, 7 October 2017

Say Goodbye To Those Sunspots... 7th October

Sadly another weekend of poor weather means that i'm unable to make any direct observations of the Sun.  Fortunately NASAs Solar Dynamics Observatory is in orbit and way above all the clouds and weather.  It shows the sunspots that have survived 2 rotations now are once again about to pass over the western limb, whether they make it around again is anyone's guess, but if they do they will likely be considerably diminished in size.  Images from the STEREO spacecraft indicates there is nothing coming around the suns eastern limb any time soon, so, it looks like we may well return to a blank disk again for a while.

Sunday, 1 October 2017

October Is Aurora Season - 1st October

For all the visual observers our star currently has several Earth sized spots visible in only modest equipment, alas these are dying active regions, and with their stable magnetic fields offer little in the way of promise for flares.  It is at these times we look at the sun in other wavelengths to see how our star can influence our planet.  In this image taken by the Solar Dynamics Observatory the large dark area just to the bottom left of centre disk is a coronal hole, this area on the Sun has open magnetic field lines, and as such is spewing plasma and charged particles out into inter planetary space.  This could well impact Earth as early as October 4th sparking displays of Aurora in northern polar regions.  October is statistically the second best month (after March) for seeing aurora.  Fingers crossed for great displays!