vdB14 and vdB15, Camelopardalis

Partly due to the weather, mostly due to recognising foibles and problems in my gear, it’s been ages since I made an astro image worth publishing.

vdB14 and vdB15, Camelopardalis

I shot in OSC (one-shot colour) using the QHY 268C camera, using two filters (a Neodymium light-pollution filter and IDAS NBZ dual-narrowband) for a total of over 30 hours’ data over the course of 3 nights in the past fortnight, of which I kept 20.9 hours.

Prints, cards, masks, clocks and other products featuring this image are available via my ShinyPhoto website: vdB14 + vdB15, Camelopardalis.

A full write-up detailing all the data captured and how it was processed can be seen over at my Telescopius page: vdB14 + vdB15, Camelopardalis

This one feels rather good ­čÖé

Seeing the New Year in with style

Over the course of New Year’s Eve I saw several aurora alerts. On checking, it was even visible as a pale grey band running above the neighbours’ houses, so I grabbed a camera and tripod and found a convenient path with a clear view to the north.

This was taken at a minute past midnight – some evidence of fireworks in Crieff with a wonderful aurora arcing over Strathearn.

Ringing-in the New Year with fireworks in Crieff from Auchterarder... with an aurora arching overhead.

Ringing-in the New Year with fireworks in Crieff from Auchterarder… with an aurora arching overhead.

Out in the middle of nowhere

On a whim, a friend and I spent a few hours out in the middle of nowhere, Aberdeenshire – hunting aurora which totally failed to show, avoiding fog and pointing cameras sky-wards to see what could be seen.

I quite liked the lights of a cow-byre against the mist, the Pleiades and Hyades star clusters in the constellation of Taurus and a little wisp of cloud below the rising moon.

Aurora!

For the second time, I was lucky enough to see the aurora from Perth, last night. It was quite an impressive display; by the time I got out to darker skies it was quite low above the horizon, but the greens were strong to the naked eye and some strong rays came and went over time.

I still need to work on a good viewing location, but out beyond Rhynd is a good start.

Moody Eclipse Photos

I was up early on the morning of March 20th to get to Stonehaven on the coast in time for the solar eclipse.

It’s funny how there was so much discussion as to what filters one should use when shooting the sun: on the one hand, a direct view of the sun’s disc requires special Baader solar filter (approx 23 stops’ filtration); however, when I arrived to see the extent of the clouds, only conventional photographic filters were needed (a mixture of ND1000 and circular polarizer 2-stop filters). And I think the results were all the more dramatic for it, too.

The first of these photos was made using a Centon 500mm mirror lens over 20 years old – from when I bought my first film SLR (a Canon EOS500n – that dates it) It even shows sunspot N 2303 pretty clearly.

The others are with the Sony 55-210mm lens at full stretch instead.

Each image is an HDR of 3 source frames bracketed +/-1EV, converted in photivo, blended in enfuse and worked in darktable.

Solar Eclipse 2015: a teaser

After all that driving to get this, I couldn’t let today pass without posting┬átaster shot from the solar eclipse.

I find it interesting that, for all the posturing online about the need for Baader solar sheets and that ND filters wouldn’t provide enough protection, nature provided clouds as the best kind of filter anyway.

The colour photo was taken with a 20-year-old Centon 500mm f/8 mirror lens and probably an ND8 filter hand-held in front; the black and white image was the kit telephoto 55-210mm lens at the far end.

Both taken from the road beside Dunnottar Castle, Stonehaven.

Noctilucent Clouds

Noctilucent (“night-shining”) clouds are a rare phenomenon: the highest clouds in the atmosphere, at altitudes between 47-53 miles, consisting of tiny crystals of water ice about 100nm in diameter and requiring very cold temperatures to form.┬áNot fully understood, they are a recently discovered meterological phenomenon with no record of their observation before 1885.

They also make a beautiful display of pale bright fibrous blue against the cobalt velvet of night…

Noctilucent Clouds Noctilucent Clouds

Two views, part of a stitched panorama.

ISS

I did only say this blog would be mostly mobile photography. Time for something a little different.

Thanks to a tip-off from a Facebook page and some friends in Leeds, a couple of nights ago I watched the International Space Station passing overhead for the first time. I didn’t know what to expect; the magnitude (-3.0) hinted at it being “incredibly bright”, and indeed so it was. Bearing in mind I had no idea what to expect, the less said about those attempts at photographing it, the better.

But last night, I investigated further using Heavens Above and saw another passing was scheduled for 2329hrs. Seeing the weather conditions were favourable, I chose a location toward the top of a nearby hill and stood around to wait.

Approaching from the west:

The International Space Station approaching from the west

disappearing toward the east:

The International Space Station approaching departing to the ESE

 

Some notes on the image processing:

The approach image comes from 6 frames at ISO800, f/4, 14mm, 15s each, taken in quick successsion; the departure image used 12 frames at ISO800, f/5, 29mm, 30s each. The high ISO was chosen partly in order to give me a chance to compose and track, partly to ensure the ISS showed up bright against the background. Both apertures are fairly wide to maximize the light captured yet give a reasonable depth of field in the landscape given the wide-angle focal lengths in use (I had pre-focussed the camera on infinity half an hour before setting out). High-ISO sensor noise is thermal and therefore random; however, long-exposure sensor noise gives a fixed pattern of hot and dead pixels. Therefore, by keeping the exposures short at 15-30s I was able to pan between shots, aiding the composition (the ISS’ path is subject to slight changes at the last minute), meaning all pixels could be calculated from more than one image with spatial offsets – stacking reduces image-noise. Finally, I took a dark frame (with the lens-cap on) to record the actual noise profile.

Initial RAW conversion used RawTherapee in order to subtract the dark-frame; images were stitched together using Hugin and enfuse biassed toward image entropy for high quality landscape and sky tones; because the averaging process reduced the intensity of the ISS’s track, I further blended the intermediate aligned images using ImageMagick and the maximum operator and overlaid the results selectively using the GIMP. Final colour toning and spatial control (high- and low-pass filters) was done in Darktable.

Update 2013-06-18: the approach photo is now available for prints or download at 500px.