stacking up

I thought yesterday's SeeStar shot of the moon was good.

But my other half also took a SeeStar video of it.  Why would you take a video of a static scene?  To enhance the view.  He spent today fiddling around with AutoStakkert!, software to stack multiple frames to get a better image.  The result is great, much crisper:

Why not just use the SeeStar to integrate over a longer time, like with other images?  Well, it doesn't do that for solar system objects, so we just have to try harder.

He also played around with a solar video taken at the end of May.  Here's a simple image:

2026/05/29, 17:48 BST

And here's the result of processing the video, with much more detail visible on the sunspots:

further and further

 Another day, and the moon and Venus are even further apart.

Venus just visible on the far right. Photo taken with a Pixel 10 camera; 22:14 BST

This time we were ready with the SeeStar telescope, although, of course, it couldn't get both in the same frame!  The moon looks better with the right focus and exposure:

SeeStar S50 photo, 250mm, f/5, 1/100s exposure; 21:50 BST

and yet it rotates

 Two pictures of a spotty sun, taken roughly 24 hours apart.

2026-05-29 16:48 GMT

2026-05-30 15:10 GMT

Look closely, and you can see that the spots have the same pattern, but have moved.  The sun rotates!

No matter how much we improve our ability to take photographs through our telescopes, we will never achieve anything to rival this amazing video, taken in October 2014 from NASA's orbiting Solar Dynamics Observatory:

sequestering carbon, several books at a time CLX

 The latest batch:

A friend was having a clearout, so we got a few old classic computer books.  And the ZWO SeeStar User Guide should help us make better use of that telescope.

Jupiter pinwheel and moon

More fun with the SeeStar telescope this eveneing.

A nice shot of the moon:

An overexposed Jupiter and four moons:

clearly, we need to learn more about adjusting the exposure

The Pinwheel galaxy, M101, 11 minute exposure:

The same image with some simple postprocessing:

clearly, we need to learn more about postprocessing

seeing Uranus move

Last Wednesday, as well as getting a SeeStar photo of the Crab Nebula, we also took a picture of Uranus.

5 minute exposure : can you spot Uranus?

The problem is, Uranus looks like a star at the resolution of this telescope.  But, planets wander; it's there in the name.  So, we took another picture on Saturday, when we were also looking at the Orion Nebula.  Putting the two images side by side makes it clear which spot is the wandering planet, and which spots are the fixed stars.

 18 March, 5 minute exposure                                     21 March, 2 minute exposure

Blinking between the two images shows the movement well (but also shows that one image is very slightly rotated with respect to the other).

So how far across the sky does Uranus move in 3 days?  Well, its orbital period is 30,688.5 days, during which time it travels once round the sky, through 360 × 60 arc minutes.  In 3 days, it will therefore travel about one ten thousandth of this, or just over 2 arc minutes, or about 1/15th of the angular diameter of the moon.  So definitely enough to be visible.

M42 photo

 Another clear night tonight, another great SeeStar photo, this time of M42, the Orion Nebula.

3 minute integration, no post processing

The SeeStar takes several shots, and stacks them.  This 3 minute integration comprises a stack of 18 shots, each itself a 10 second exposure.

M1 photo

Tonight was quite clear, so we played with the SeeStar telescope.

We got a nice picture of M1, the Crab Nebula.  You can even see colours!

10 minute integration, no post processing

We tried Jupiter, but it was over-exposed, even with the exposure turned down as much as we could.  We need to try playing with the settings a bit more.  We could see the moons, though.

A too-bright Jupiter and four moons. Must try harder.

spots and birds

The sun is very spotty today.

15:54 GMT, taken with out SeeStar telescope with solar filter

The SeeStar allows us to take videos.  The sundoesn't change much, but a short video showed something rather fun.

Blink, and you might miss them.  Here's a still frame:

16:29 GMT.  Is it a bird? Is it a plane? It's ... a bird.

(The wobbly shadow at the bottom is a tree.)

tubular woes

The second day of Astrofest was as good as the first (better, taking into account I had significantly more sleep last night than the night before!)

Today we heard about: 

• ESA/NASA’s Solar Orbiter mission and its view of the solar poles
• Searching for micrometeorites in piles of dust
• ESA’s Science programme in general
• An interview with Gary Hunt on his 50 years in space science, including his Voyager experiences
• Interstellar magnetic fields, including a description of how the Pillars of Creation ‘fingers’ are pointing at the star forming area, with shock waves from star production pushing on the material, bending magnetic fields to form the fingers
• J-P Metsavainio’s stunning astrophotography, including a mind-blowingly detailed image of the Milky Way (zooming in to which showed lots more ‘fingers’ pointing at star formation)
• How large telescope mirrors are made
• NASA’s Psyche mission to a metal asteroid

Excellent!

Usually, at the end of the Saturday of Astrofest, we dash off to catch a train home from Kings Cross.  But it's always a rush, and the train is always packed.  This year we decided to do something different: go back to the hotel, have dinner, then proceed more leisurely to Kings Cross for a later, hopefully less full, train.

On buying tickets, we discovered there were no trains home from Kings Cross that night, due to engineering works.  The app suggested a cross country route, but we decided to travel via Liverpool Street instead.  Slower than the Kings Cross train, but not slower than the cross-country route, and on a direct tube line from High St Kensington.

So, we had dinner, collected our luggage, and proceeded to the tube station.  Only to be regaled with announcements that there severe delays on the Circle Line.  There were complicated instructions of what to do, but we instead took the District line to Earl’s Court, then the Piccadilly line to Holborn, then the Central line to Liverpool St.  So, not direct, but we did catch the main line train we had been aiming for, although with slightly less leeway than we had hoped!  We arrived home not too late, well fed, and full of great astronomy.  So we’ll probably try that approach again next year (well, eating first, not the grand tour of the underground, hopefully).

view from a London hotel window

I had a very productive and enjoyable time at the ALICE workshop in Copenhagen, working with a great team, modifying and using a system that modifies its own programming language.  We hope to get a paper out of it.  Watch this space!

Unfortunately, the last day of the Workshop clashed with a prior engagement in London: Astrofest 2026.  So I left Copenhagen on the last flight out on Thursday evening.  I knew this was a risky decision at the best of times, and then it started snowing...

The flight was delayed by two hours.

In the queue to board.  Brrr.

That meant I missed the last train from Stansted to London.  Saved by National Express!  I got a coach to Paddington.  I felt very 21st Century as I sat on the coach and used my Greater Anglia app on my phone to cancel my rail ticket and request a refund, for which I was charged £5.

I got to Paddington after 2am: the tube was shut, and there were no taxis.  I downloaded a taxi app (not Uber), and summoned a black cab.  That took me to my hotel off Kensington High Street (and cost more than my coach fare from Stansted).  

I arrived at 3am (4am Copenhagen time), but I arrived.  Five hours sleep, then breakfast (and a photo out of the window) ready for a day of astronomy talks.  

no snow!

The talks were very good, covering the JUICE mission, the Herschel telescope, the Square Kilometre Array (and its relationship to K-Pop; yes, really!), landscape astrophotography (marvellous photos), the history of Guillaume Le Gentil's tragi-comic failure to witness two transits of Venus, and galaxies in 3D (I thought the Hubble Deep field photos were mind-blowing enough; seeing them in 3D takes that experience to another level).

Well worth the travel hassle.  And more tomorrow!

After ALife

My colleague and I travelled back to Tokyo on the bullet train this morning.  I had quite a bit of time before my flight, so he suggested we visit Electric Town.  We took a local train, then searched for some empty luggage lockers so we wouldn't have to wheel suitcases around.  All the coin-operated ones we found were full.  But we did find an alternative.

A very nice gentleman took our bags and gave us a ticket.

Divested of luggage, we walked around, marvelling at the sheer variety of stores selling everything electrical, electronic, technical, cutesy twee, and much that was unidentifiable.

A huuuge multistorey shop sold large expensive items, including mega-sized TVs, bicycles, telescopes, and sharks.

I've been to specialist telescope shops with fewer items on display.

Difficult to get a scale, but this was several feet tall.

At the other extreme, there were alleyways and arcades with tiny shops selling all kinds of electronics, from small boxes full of individual resistors and transistors, to crates full of old laptops.  Everything for the hobbyist.

One shop among hundreds.

It was lightly raining and getting dark: the combination of weather and goods made me feel like I was on the set of Bladerunner.  

After that, we retrieved our luggage, and I caught a train to the airport, to wait for my just after midnight flight home.  

I like the simplicity and clarity of the airport shop names.

The end of my third trip to Japan.

differently spotty

The sun is still remarkably spotty, but rotation since Friday has changed the view:

spotty

"You want to look at the sun!" my other half yelled.  I went out with the solar binoculars, and saw many large spots.  Wow.  "Can we take photos of it with the SeeStar?"

About an hour later, after installing the solar filter, levelling the system, uploading new firmware, levelling it again, rebooting telescope and tablet a few time, and lots of muttering: a SeeStar picture!

click to embiggen

Wow!  Multiple spots. Pairs of spots. A cluster of spots.  A row of spots. A ring of spots!

Through the binoculars I could see the five big spots plus a splodge where the ring is.  But this picture is something else.

Nice observatory

The UCNC excursion today was to the Nice Observatory, barely a 20 minute coach ride up a nearby hill.  Well over 30 minutes into the journey, around scary hairpin bends, near Monaco, the driver finally admitted he had gone the wrong way.  Turning the coach on a road I swear was narrower than the coach was long had several of us recalling the ending of The Italian Job.  More swooping around hairpins, and we finally arrived at the observatory, over an hour late, and slightly nauseous.

The observatory itself was great.  We saw three historical telescopes, one of which was the largest privately-funded telescope in the world in its day.

Too large to photograph the whole refractor; inside a lovely wooden dome

Next we went to see the Coudé (French for elbow).  This was a new design, using mirrors to allow the eyepiece to stay in a fixed position: no leaping up and down giant staircases to view and adjust the scope.  Ironically, the development of mirrors good enough for this purpose meant that refractors were replaced by much more compact reflectors, so very few of this design were ever built.

The Coudé, but where's the dome?

The "dome", a moveable shed on rails

Next, on to the final telescope, in an amazing building.  Designed (somewhat literally) as a "temple to science", it has a large, recently regilded, sculpture over the entrance.

A 100 ton dome on a solid foundation, with a dramatic entrance.

A closer look

Inside, another large refracting telescope too long to fit in one photograph.

The finder scopes are themselves quite large.

The other end.

The 100 ton dome was designed by Eiffel.  A dome has to rotate.  100 tons has to rotate.  Eiffel designed a combination of rails and hydraulic support.  Today, it's just rails.

Documentation

There was an exhibition of instruments in the large dome.  Because we were so late, there was no time to see it.  Grumble.

moonlighting

While I was up in Scotland enjoying the spring sunshine, my other half was enjoying the clear night, using the 8" telescope and a Raspberry-Pi camera to photograph the nearly-full moon.

Definitely better pictures than using my phone camera.

Eight ways to observe the eclipse

We watched the partial solar eclipse quite closely this morning, with eight different instruments.

Going counterclockwise, we have:

1. A pair of solar viewing glasses from the 1999 total eclipse.
2. The SeeStar telescope with a solar filter.
3. The new solar binoculars.
4. The digital SLR with zoom lens, and, of course, solar filter.
5. The cardboard solar projector telescope, bought for the 1999 eclipse
6. The 5" Meade telescope with, you guessed it, a solar filter.

We used all the instruments, but the 5" gave the best view, and the SeeStar got the best pictures, overall.

Just starting: see the big sunspot near the limb. 
There are some smaller, fainter spots towards the top-middle of the disc.

Near maximum, and the smaller sunspots are close to the edge of the moon.

Nearly over

I snapped the sky with my phone to show that it was getting somewhat cloudy. 

The sun is completely overexposed, of course.  But wait. What's that spot on the dome?  (In case you are wondering, we couldn't use the 8" telescope in the dome for this event, as we don't have a solar filter for it.)

Look at that reflection!

So that's the seventh way we could see the eclipse (although we didn't notice it at the time, only when looking at this photo).  

What about the eighth?  Well, that's the same as the way we "observed" a partial eclipse 10 years ago, with our solar PV:

The big dip: that's no cloud, that's the (partial) eclipse)

The device to attach a phone camera to the 5" telescope arrived in the post later in the afternoon.  Oh well.  In any case, a well observed eclipse.

four or five planet evening

Clear skies, cold still weather: good seeing.  So, about half past six this evening, we looked for the planetary alignment.  We saw (with the naked eye) faint Mercury close to the still faintly pink horizon, spectacular Venus dominating the western sky, bright Jupiter near the zenith, and red red Mars a little further round.  Binoculars made them brighter, but still point like, except for Venus.  I could convince myself I could see Venus’ phase, but it was so bright, it was hard to be sure.

Later, 8:30-9pm, it was much darker, and we used the big telescope.  Venus and Mercury had set by then.  Jupiter was lower down, but still visible: we could see all four Galilean moons, and some dark bands on the planet itself.  Mars by then had moved close to the zenith.  Last time we tried to view it at that angle, we couldn’t see through the finder, so we bought a 90 degree adapter for it at AstroFest a few weeks ago.  It works!  We got to see the red planet as a disc.  Beautiful.

We had a quick look at the Pleiades, as they were in the vicinity.  My god, it’s full of stars!

We then used the autofinder to try for Uranus.  We could see a bright object near the centre of the field of view.  It could have been a very small disc of a planet, or just a point source of a star.  I choose to believe it was Uranus.

So, definitely four planets, and maybe even five.

new toy

AstroFest has a lot of exhibitors.  Last year we bought a small SeeStar telescope, and a dome for the big telescope we bought back in 2020.  This year we were a little more restrained.  

We had recently been looking at Jupiter with the big telescope; we had also tried for Mars.  But Mars is high in the sky at the moment, which means the telescope is almost vertical.  We have a 90 degree adaptor for the eye piece, but not for the finder scope.  It was too difficult to limbo down to look up through the finder, so we didn't see Mars.  Thanks to this year's AstroFest, we now have a 90 degree adaptor for the finder, too.

A quarter of a century ago, August 1999, we viewed the total eclipse of the sun.  For that, we bought a Lightline Solar Projector, a clever cardboard tube and lens contraption that allowed us to project an image.  We have been using it since to view the sun, but it's not particularly good for seeing sunspots, and is getting a bit battered.  We have a solar filter for the new SeeStar telescope, which gives us a spectacular view, but takes a while to set up.  While wandering around the exhibits, I saw a variety of "solar binoculars", binoculars with built-in solar filters, so they can be used to directly view the sun (and nothing else!)  I was debating whether to get a pair, when one of the other attendees struck up a conversation.  She said she had bought a pair previously, and had spent many a happy time watching the sun.  She convinced me, so I bought a pair.

The weather forecast is cloudy for the next week.  So I'll have to wait to try them out!

view from a hotel window

Another year, another AstroFest.  We stayed at a different hotel this year (next door to the previous one), in the hope it would be quieter: it was!  But the view wasn't quite as interesting:

Two days of fascinating talks again, on aurorae (the ones last year were some of the most southerly viewable ever), Mars, forthcoming eclipses, astrophotography (the quality of "amateur" photography today is streets ahead of professional photography several decades ago), black holes, observatories on the moon, star surveys, the UK Space Agency, star formation, the Antikythera Mechanism, exoplanets, and Enceladus.  Something for everyone.

And the exhibitors had bigger than ever telescopes on offer, including one mount with four large telescopes on it!  A bit beyond our budget, but nevertheless, the shape of amateur things to come?

The train down (Thursday afternoon) was 12 nearly empty coaches.  The train back (Saturday evening) was eight packed coaches: we had to stand.  Two different people offered me their seat: I must look older than I think I do!  I politely (I hope) declined: I had after all been sitting down all day at the event.