Solar observing: last year and now

My solar observing season tends to run from about February to the end of October. As I’ve noted before the Sun is too low to clear the roofs of the surrounding houses.

For the last few seasons I’ve been sketching the view of the solar disc through my Coronado PST (Personal Solar Telescope) and occasionally augmenting that with white light details of Active Regions (ARs).

I thought it might be interesting to compare the views from this time of year. I only started seriously recording at the end of the 2016 season, so the record isn’t a long one, but at least both the images below were made using the same equipment and are limited to Hα views.

At the first glance, and doubtless due to my artistic talents, you’ll find that the Sun appears to be about the same: not especially active. A closer look and a scan of the notes reveals that there’s quite a difference.

Hα sketch from 18 May 2017
Hα solar disc sketched on 18 May 2017 with a PST and Baader Zoom.

So to get the ball rolling I present my sketch and notes from mid-morning on the 18 May 2017.

This view is sporting three substantial ARs with a sunspot visible in the PST. For sunspots to appear in Hα normally means that they’re large and plain to see in white light, something I’ve noted. I also note being able to see even more sunspots that way.

There are also some good prominences and their cousins from the solar disc, the filaments. I’ve also added notes about the central AR12657 showing a tight knot in the fibrils that cover the surface of the Sun.

Hα sketch from 17 May 2018
Hα solar disc sketched on 17 May 2018 with a PST and Baader Zoom.

Moving on to my sketch from around midday on 17 May 2018 it’s a very different story.

I’ll admit that mid-morning is a much better time to observe the Sun than midday as the intense heat from the midday Sun stirs up turbulence in the atmosphere, but still, that is a quiet Sun!

Only AR12709 is visible with a pair of quiescent prominences – reasonably large though – and a few small filaments. There are no notes about the white light view because there was nothing much to see.

The next couple of years might provide more of this as we pass through a Solar Minimum. That’s not to say that we can’t get some excitement, it’s just not as likely nor frequent.

I’m hoping that the pessimists predicting a Solar Grand Minimum like the Maunder Minimum have got it wrong.

All that said, there’s the nice detailed AR12712 on the face of the Sun as I’m writing this (a little delayed by software issues) according to SolarMonitor.org. It’s got multiple spots and is now classed as type βγ which could produce some small scale fireworks.

Unfortunately for me it’s firmly on the wrong side of some persistent clouds and thunderstorms here in the UK. If you can see the Sun enjoy the view but always with the appropriate equipment.

Update!

Would you believe it the Sun came out this lunch time! I’ve had a good look in both Hα and white light and even got the time to make a sketch before the cloud returned. There’s a lot to see in AR12712, I wish the seeing has been a little steadier, but you can’t have everything.

The Return of Solar Observing

As the days of British Summer Time get longer a compensation for me is that the Sun is rising high enough to be visible again from my northwest facing garden.

I love my solar observing in both the Hydrogen Alpha (Hα) wavelength of the Balmer series, using a Coronado Personal Solar Telescope (PST), and with a normal telescope in white light, but with a Herschel Wedge removing around 99% of the available light for safe observing.

Considering that we’re near solar minimum there’s been a surprising amount of activity to be seen around the end of March and the beginning of April. The most dramatic events have been in Hα, but even white light views have been impressive. The cause of the excitement has been a pair of large Active Regions (ARs).

The first of these (AR12644) produced some large eruptive prominences as it exited the face of the solar disc on 3 April. I was lucky enough to be observing then with the PST with a Baader Zoom eyepiece, and the events were fabulous.

I don’t image, and was too busy observing to sketch, but fortunately NASA does image almost continuously with the Solar Dynamics Observatory (SDO) from orbit. This is what they came up with, and despite their use of the ultraviolet part of the spectrum it’s not too far from the PST view in the red of Hα (656.3nm).

SDO image of AR12644 at 30.4nm taken on 3 April 2017
An image of AR12644 on 3 April 2017 at 30.4nm wavelength by the Solar Dynamics Observatory (SDO). Credit: Solar Dynamics Observatory, NASA.

It is just a little more detailed and has a larger image scale. They also have some movies of this solar eruption, and trust me, you could see that big prominence changing before your eyes!

I checked out the white light view too, but there was no indication of the violent events to be seen. The clusters of sunspots and surrounding faculae were plain to see in all their intricate detail despite sitting right on the limb in the image below. It was taken by the SDO HMI instrument, but is very similar to my white light view.

SDO HMI Intensitygram of AR12644 and AR12645 taken on 3 April 2017
HMI Intensitygram of AR12644 and AR12645 3 April 2017. Credit: Solar Dynamics Observatory, NASA.

In its wake followed the equally large AR12645 in the lower left of the image below. If anything it was more impressively detailed in the wedge, and I found it to be naked eye visible through some Baader solar film (another method for safely viewing the Sun). It didn’t produce any Hα fireworks, but the sharp filaments and swirling patterns in the spicule and fibril background of the solar chromosphere were beautiful to observe.

These ARs were great to view throughout their transit across the face of the Sun, but will they survive to reappear for another transit?

A Feast of Astronomical Observing

And now I’ve forgotten to post through March… which is a shame because it was a huge improvement over February. Not only a big uptick in the quantity of observing opportunities, but lots of variety in my observing diet too.

Both this month and the last have started with some Lunar observing. I’m starting to take this increasingly seriously just as the Moon is due to sink lower in my sky until it disappears behind the house until Autumn… still you have to start sometime, and I’ve decided now with the Charles Wood’s Lunar 100.

Which is why I’m very happy to welcome the return of solar observing. As the Moon sinks, the Sun is getting higher in our northern hemisphere skies, so it’s around now that I start to swap lunar for solar observing. Despite being around solar minimum, with relatively few sunspots to be seen, I’ve been rewarded with some Hα fireworks and spectacular white light sunspots in the last few weeks. Few in number perhaps, but the quality was undiminished.

Planetary observing wasn’t left out as I followed the sliver of Venus up to the last possible moment. For me that was the point it fell behind the houses and trees to the west at sunset on 15 March 2017, but it was a very thin crescent by then: I estimated 5% and Stellarium claims 4.4% illumination. I’ve caught a glimpse of Mercury at sunset too.

There were several Jovian sessions, even though it’s a bit too low to see well from my back garden. I can observe Jupiter low to the SE over the top of my garage for about 30 minutes before it goes behind the house. No moon transits yet, but a look at a slightly washed out Great Red Spot (GRS) was possible in my 60mm refractor. Why the small scope? To have any view I have to pick my position carefully, and you try manhandling a large telescope into the garden undergrowth.

I’ve tried to spot the comets 45P/Honda and C/2015 V2 (Johnson) with my binoculars, but with no success. At first they were too faint or low, then the Moon arrived and I haven’t bothered again. Once the Moon disappears I’ll certainly try again for the latter of the two at least.

March witnessed the arrival of British Summer Time (BST) which heralds the rapid shortening of night in these parts. Naturally in astronomical circles this is never well received, and Deep-Sky observing isn’t going to be easy! By the end of May there’s no astronomical darkness for a couple of months, but in the meantime there can be some lovely transparent skies for the patient.

After a rather wet period in the middle of March, during which the Moon got out of the way, clear skies returned just before BST inflicted itself upon us. I’ve started working on the Herschel 400 list again. This spread of several nights gave me the chance to start on the faint and fuzzy galaxies of Spring, as well as polishing off some surprisingly faint open clusters from late Winter.

Finally, I’ve collected a few more variable star observations thus clearing the backlog a bit and responding to an AAVSO alert on AG Dra (one I regularly follow). The conditions haven’t been great for it: patchy cloud doesn’t kill a lunar session, but it makes reliable binocular variable estimates pretty tricky. Still it’s nice to be logging some data again.

So a March was a much better month and April has started in stunning style with observing sessions on each of the first seven days!

Partial Eclipse

The morning of the solar eclipse and looking to the East it’s not a pretty picture. I can see the location of the Sun, which is a major advance on yesterday, but it’s not even bright enough to show up through the solar filter… not good.

Optimism wins out, and I decide to set up the solar telescopes – white light and hydrogen alpha (Hα) – before having breakfast in the hope that luck will be with me today. It owes me a break since the night time trend is for me to get cloud when others get pristine skies.

Breakfast out of the way I’m asking myself whether it’s clearing. It looks like it is, but which way are the clouds going? I’ll take a look with the Herschel wedge on my ST-80. I can see the whole solar disk and think that the remaining light clouds lend an atmospheric touch as the sunlight bounces off them. But wait, is that a notch appearing in the circular face of the Sun? Yes! The game is on.

I watched the Moon slip across the face of the Sun, pausing to make notes and quick sketches of what I could see. The Sun is very active in Hα and some of the prominences became divorced from the Sun – detached isn’t the word, these were in limbo, now above the Lunar limb! I noted the time of first and fourth contact, and when a lonely sunspot group was occulted and later reappeared.

At maximum the temperature dropped, the sky took on a twilight feel, but the colour was different. Imagine a blue sky that’s fallen in luminance, a bit like that, purple for me and my dodgy colour vision. The birds actually clammed up, they’d been active until that point.

I noticed the temperature drop caught out the relative humidity. It had been dropping too as the morning progressed, but water was suddenly unhappy being vapour and my breath sent plumes across the garden. Weird would be a good word for it.

I could have imagined it, but it looked like there was some spillover of light onto the northeastern limb of the occulting Moon. In Hα I thought I could see some detail there. Very faint if it was real at all and not a product of the optics.

The house started to get in the way, so I had to be creative with the repositioning of my equipment around the garden to watch the next phase of the drama. But it was all there – much to my surprise – from beginning to end, first contact to the last.