Pleiades overnight

A clear, cold night with excellent seeing was the forecast for Monday, 28th November, so I set up in the back yard for an overnight session. Messier 45 “The Pleiades” would clear the tree line at 21.33 (south-east, elevation 53°) and disappear behind the roof line at 02.29 (south-west, elevation 45°) the following morning. Perfect conditions for leaving the system running on its own.

The initial polar alignment of the mount was accurate to 7 arcmin, reducing to 3 arcmin after one iteration of the handset’s feedback routine. Something wasn’t right, as the feedback routine wouldn’t display all the required information to make the proper adjustment, so I had to resort to twiddling the knobs “about the right amount” from an earlier manual calibration session.

3 arcmin of alignment error (with the focal reducer at 636mm focal length) means one pixel of trailing in about 135 seconds, so I set the timer for 90-second exposures with 30-second pauses for the sensor to cool down between frames. 30 frames per hour over 5 hours would net me 150 frames.

My alarm clock went off at 2.30, when I switched off the mount, screwed the end cap on the telescope, set the camera timer to take another 65 “dark” frames and went back to bed. The battery-operated dew heater kept the telescope objective above freezing, but the camera was frosted over the next morning.

150 frames take some processing, and the cooling fan on the Mac was up to full speed by the time I’d finished. Some of the nebulosity has been sacrificed in the processing, as there was a most unwelcome flare in the centre of the photo – probably an urban light source? This target never climbs more than 60° above my local horizon: at its highest elevation, it is due south right across town, and something was the right wavelength to get through my IDAS D1 light pollution filter.

Still a pleasing result for a session devoted to one of the classic targets.

M45 "The Pleiades" Nikon D90 on Altair Wave 115/636 ISO800, 150 x 90 sec.

M45 “The Pleiades”
Nikon D90 on Altair Wave 115/636
ISO800, 150 x 90 sec.

New Year’s Day Comet While Changing A Wheel

Sometimes it’s really hard to motivate yourself to get up at 3am for astronomy.  I’m more of a late night person myself, and early mornings are not my style.  One way to make it happen, to get that motivation going, is to share your intention with a friend – preferably one who is relying on you for a lift.  So it was that I set my alarm for 02:50 on New Year’s Day.  Clear skies and the knowledge that a fellow enthusiast was doing the same, meant that I was up and out in about ten minutes, including making a flask of coffee.

When I picked Stuart up in the centre of Kendal, he’d already bagged the Aurora Borealis – the Northern Lights, if you prefer – at around midnight that same night.  His dedication to the cause is beyond all understanding, and puts my meagre efforts to shame!

We had two options: a site at the top of Shap Road – dark, clear, cold and very exposed (ideal for stargazing) – or the church car park at Old Hutton – not quite so dark, low lying (so prone to localised humidity), still cold but nowhere near as exposed.  Stuart reported very strong winds across Shap Fell at midnight, as had been forecast, so we set off on the short drive to Old Hutton.

About a mile before we arrived, we found the road closed at a barrier, so turned off to the left on a tiny side road and navigated round a big loop to rejoin the main road on the other side of the diversion.  The side roads were a real mess, and somewhere in the darkness I hit a massive pothole.  By the time we arrived in the church car park, the front tyre was completely flat.

Keeping to the right priorities, we both set up our systems and started taking photos.  There followed some stargazing, some musing on the recent awful weather, some discussion of my much-anticipated observing evenings for the Eddington Astronomical Society, a review of Stuart’s aurora photos from earlier that night, some coffee drinking, and of course much delight in the images now coming off the backs of the cameras.  Eventually, though, we just had to attend to the wheel change.

Everything went smoothly until the nearside front wheel was jacked up in the air and the wheel nuts were off.  The wheel itself just wouldn’t budge, and our efforts to dislodge it by repeated and ever-more-vigorous kicking came close to waking the neighbours and/or sending the car toppling off the jack.  5am, New Year’s Day, remote village in Cumbria, no signal.  Hmmmm….  Only a joint effort, one pulling the wheel while the other aimed kicks at the opposite side, eventually freed it.  Phew!  Suffice to say that the rest of the session went very well indeed.  The conditions looked good – but they can be quite deceptive at Old Hutton as the local shape of the land collects moisture in the air – so the photo sets were as good as we could have expected.  Some hazy cloud lingered high in some frames, but nothing to stop us until about 6.30 when mid-level clouds started to spoil the view.

I took a series of 2-minute frames and 3-minute frames (all unguided) of C/2013 US10 (Catalina) at its closest approach to Arcturus, the brightest star in the constellation of Bootes.  Given the moisture in the air, the close proximity of the bright star, the Moon just 38° from the comet and all that other stuff going on, I was pleased with the result.  Given also that the weather in Cumbria has spoiled all plans for astrophotography for the last eleven weeks, it just felt good to be out again.

combined-catalina-arcturus

Comet C/2013 US10 (Catalina) passes half a degree from a very hazy Arcturus
Nikon D90 through Altair Wave 115/805 reduced to f/5.5
11 x 3 minutes, ISO 400

I hope we find the opportunity for  a few more of these Stuart!

The dilemma of self-interest -v- public outreach on eclipse day!

The solar eclipse of Friday 20th March 2015 presented a real dilemma: as an enthusiastic and committed member of the Eddington Astronomical Society, I wanted to be part of the event organised in Kendal, but as an individual amateur astronomer/astrophotographer, I wanted to see (and film) the eclipse.  Kendal was forecast to be under cloudy skies, but a couple of hours drive would take me away from all my EAS colleagues, two radio stations and 500 enthusiastic members of the public, beyond the edge of the cloud layer to full sunshine.

After much soul-searching the night before, I set the alarm for 4.30am.  The first job was to check the forecast again – yes Kendal was still going to be cloudy, but Oswestry (about half an hour south of Chester) would be clear.  Self interest won the battle, so after a quick coffee and a final kit check, I hit the road.

This was my intended destination, from Google Maps.  I liked the look of the car park at bottom right, with unimpeded views over the golf course.

Oswestry

Mile end

car park view

I arrived in good time to go and say Hi to the staff at Little Chef, use their facilities and buy a Cappuccino, then on with setting up the rig.  The AZ-EQ6 mount will take two scopes in Alt-Az mode, so I had rehearsed a configuration with the Altair Wave 115 carrying the Nikon D90 on one side, and the Skywatcher Evostar 102 with a 15mm eyepiece on the other.  A triple thickness of Zoltan Trenovski’s business card was needed as a shim to align the tubes just right.

setup2

setup1

A couple of test frames to check the focus and the exposure:

sun too bright

too bright…

sun out of focus

too blurred…

Focal length 636mm f/5.53 1/400 sec ISO 200

Focal length 636mm f/5.53 1/400 sec ISO 200   Just right!

At six frames per minute, within 10 minutes there’s a clear view of the eclipse starting.

viewfinder

After 864 frames and a weekend of aligning and processing, we have half a minute of time-lapse video 🙂

There’s lots more to be said here – other people had had the same idea and we spent time comparing notes, the wonderful manager of Burger King / Little Chef kept bringing me free coffee and letting her staff come out to take a look through the telescope, everyone who used the carpark came to have a chat, and of course someone had brought a colander…

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The coffee supply!

IMG-20150325-WA0003

Doing optical experiments with kitchen equipment…

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Spotting scope and a beautiful Televue both with solar filters.

colander

I hope that some of the wonderful characters gathered in the carpark that morning will manage to get in touch and send their photos to simon.white@simoninthelakes.co.uk so that I can display them here.  I’ll update this post with anything they wish to add.