Spring galaxies

Not sure why I haven’t posted for a while, as there was a spell in April when we had a string of back-to-back clear nights.  There were opportunities galore to capture springtime galaxies, and I found new locations such as Elterwater carpark to take advantage of dark skies.

17 April, with some cloud in the east, I headed to the centre of the Lake District in pursuit of “Markarian’s Chain” using my new protocol of guided 10-minute exposures.   Elterwater is a small village in the Langdale valley, but has a good accessible hard standing carpark where I set up my system.  The netbook computer guides for only a couple of hours on its old battery, so once it’s up and running I have to get on with it.

The target was Markarian’s Chain of galaxies just east of Leo, and I managed six frames of 10 minutes each before the clouds chased me down.  One frame was a little hazy, so the result is a stack of 5×10 minutes.  Darkness was good, but disadvantages of Elterwater include some very bright outside lights on tourist rental properties, and large camper vans using the carpark for overnight stays.  Also it is low altitude and a bit of a bowl for mist and condensation.

That said, there are 25 or more galaxies easily seen in this photo, and the stats are mind-boggling.  Most objects in this frame are over 50 million light years away, and the galaxy in the bottom left corner (M87) is a million light years from M84 at the right hand end of the chain.  Galaxy NGC4388 at bottom right (the “smile” on the face at the front of the chain) is 11th magnitude, which makes it less than 1% of the brightness of the faintest object visible to the naked eye from a dark location.  The galaxies are gravitationally bound to one another, despite the incomprehensible distances involved.  All that with a Nikon D90!

Markarian's Chain: M64, M86 and others in the Virgo Cluster. Nikon D90 on Altair Wave 115/805 (f/7), ISO 400 50 minutes: 5 frames of 10 minutes each.

Markarian’s Chain: M84, M86 and others, plus M87 in the lower left corner, all in the Virgo Cluster
Nikon D90 on Altair Wave 115/805 (f/7), ISO 400
50 minutes: 5 frames of 10 minutes each.

On the night of 18 April, M101 was at zenith, captured here in 9 frames guided at 10 minutes each.  That’s a total of an hour and a half on one galaxy, which is a lot for me (until now!).  10 minutes is fantastic for light gathering, but pushes the boundaries of long exposure v potential for disturbance.  If a car drives past, or if a strong gust of wind nudges the system – or even if the guiding software momentarily loses sight of the guide star – then the whole 10-minute frame is spoiled.  These were taken in the long layby on the A591 outside Staveley, which is sheltered but by no means unused, and I was fortunate that there was almost no traffic that night.

M101 Nikon D90 on Altair Wave 115/805 (f/7), ISO 400 90 minutes: 9 frames of 10 minutes each.

M101
Nikon D90 on Altair Wave 115/805 (f/7), ISO 400
90 minutes: 9 frames of 10 minutes each.

On 21 April, I was back on the Shap Road with fellow members of the Eddington Astronomical Society, and my target this time was M106, again at zenith.  Thirteen frames of 10 minutes were reduced to nine on closer inspection (gusts of wind spoiled four), so this is also a stack of 9×10 minutes.  In calm conditions I seriously wonder whether the DSLR could cope with 15 minutes per frame; with the ISO at a comfortable 400, there is very little by way of glow from the sensor.  What level of detail might be possible with three or four hours total exposure?

Nikon D90 on Altair Wave 115/805 (f/7), ISO 400 90 minutes: 9 frames of 10 minutes each.

Nikon D90 on Altair Wave 115/805 (f/7), ISO 400
90 minutes: 9 frames of 10 minutes each.

Finally, on 26 April, a quick experiment from my own back yard.  With high buildings and trees obstructing a clear view of the sky, it’s not possible to go through the star alignment process on the GOTO handset, so I’m restricted to polar-aligning the mount by eye.  I hoped that with 5-minute frames, the guiding system might smooth out the alignment error.  Here’s 20×5 minutes on M51, with the ISO wound up to 800, suggesting this has some promise.  There’s light pollution from next door’s uncurtained landing window, so a light pollution filter might be a useful addition to the armoury.

Nikon D90 on Altair Wave 115/805 (f/7), ISO 800 100 minutes: 20 frames of 5 minutes each.

Nikon D90 on Altair Wave 115/805 (f/7), ISO 800
100 minutes: 20 frames of 5 minutes each.

Galaxy M51 flyby

Over the first few days of May, comet C/2012 K1 (PANSTARRS) flew past galaxy M51 (The “Whirlpool” Galaxy).  On the night of 2 May, I was out on the Tebay Road until the very late early hours of 3 May, making just about every mistake in the book as I tried to assemble a three-frame mosaic of the flyby.

I could have got the whole picture in the frame of my 300mm lens, but decided to take three adjacent frames through the telescope, the equivalent of an 805mm lens.  The idea was to take the three frames, 20 exposures of one minute for each frame, and stitch the results together to make one 36-megapixel photo with a total exposure of about an hour.

It was an ambitious project, and getting it completely wrong taught me a load of new lessons about the scope, my method and all that complicated stuff about knowing your left from your right…

mosaic2500low

You get the idea, don’t you?  Always stick to the plan, because recalculating at 2am with a notepad and a red torch when half your frames have been spoiled by clouds and the rest ruined by a succession of schoolboy errors, can only lead to misery.

Fortunately I had also programmed a remote scope with iTelescope.net under the New Mexico skies, so I had plenty of processing to play with over the weekend.

3 May 2014: Comet C/2012 K1 (PANSTARRS) passing the Whirlpool Galaxy M51. iTelescope.net telescope T14, 106mm Takahashi FSQ. Camera SBIG STL-11000M. 9x3minutes Luminance, 1x3minutes each RGB.

3 May 2014: Comet C/2012 K1 (PANSTARRS) passing the Whirlpool Galaxy M51.
iTelescope.net telescope T14, 106mm Takahashi FSQ.
Camera SBIG STL-11000M.
9x3minutes Luminance, 1x3minutes each RGB.

Now that’s what I call a flyby!

If you fancy a go at processing this image yourself, please feel free to copy the original calibrated frames from DropBox here.

 

Two clear nights in a row!

Aaahhhh… late April in Cumbria!  Sunny days turn into clear nights, and we had two in a row for a change.

On 19 April, I returned to an old favourite location at the top of the Shap Road.  Like the previous night, my first target was the comet C/2012 K1, which I will try and capture at each session with identical exposure and processing in order to observe the comet’s development.  It was a windy evening high on the Shap Road, with the electricity pylons and their cables making some strange wailing sounds.

20140419_C/2012_K1

Job done on the comet, now I can relax and tackle a couple of other targets.

First, the Whirlpool galaxy M51, an iconic feature of the northern night sky and one of the “must have” shots in any astrophotographer’s portfolio.  I’ve seen it many times in books, magazines and online but believe me, the first time you take this yourself is a very special moment.  It is a faint object, at magnitude 8.4 it is way beyond naked-eye visibility, and individual frames show very little even at 60 seconds exposure.  But when it emerges from the processing software…

19 April 2014: M51 "The Whirlpool Galaxy" from Shap Road. Altair Wave 115/805, ISO 1250, 20 minutes. 20 frames of 1 minute.

19 April 2014: M51 “The Whirlpool Galaxy” (Mag 8.4) from Shap Road.
Altair Wave 115/805, ISO 1250, 20 minutes.
20 frames of 1 minute.

Then another iconic target, this time quite low over the southern horizon towards Kendal, the Sombrero galaxy M104.  Another WOW! moment when this comes up on my processing screen.

19 April 2014: M104 "The Sombrero Galaxy" from Shap Road. Altiar Wave 115/805, ISO 1250, 20 minutes. 20 frames of 1 minute.

19 April 2014: M104 “The Sombrero Galaxy” (Mag 8.0) from Shap Road.
Altiar Wave 115/805, ISO 1250, 20 minutes.
20 frames of 1 minute.