Category Archives: Deep-Sky Imaging

A new era of deep-sky imaging at the New Forest Observatory

The Canon 200mm f#2.8 prime lens gives remarkable performance for astroimages across the whole diagonal of a full frame sensor.  I am using the lens with a Canon 5D MkII (unmodified) which means that I can capture star fields quite well, but not the faint red emission nebulosity – and I have a massive field of view of 10 x 6.8 degrees to play with (where the diameter of a full Moon is just half a degree).

I also have a huge portfolio of faint deep-sky objects captured using the Hyperstar III – so I am now in the happy position of being able to grab huge star fields in one go using the DSLR and then filling in any faint objects using Hyperstar III data – a process called compositing.

The image below is a 10 x 6.8 degree deep-sky image centred on the Cocoon nebula in Cygnus.  Towards upper right we have open cluster M39, towards lower left is open cluster NGC 7209, and towards upper right is a large open cluster NGC 7243.  Trailing behind the Cocoon nebula we have the highly impressive dark nebulosity Barnard 168, one of the most high-impact naked-eye nebulosities in the northern hemisphere.

The combination of the 200mm/Canon 5D MkII and Hyperstar III data is going to feature highly in forthcoming deep-sky images from the New Forest Observatory.


The Canon EF 200mm f#2.8 prime lens for astrophotography

I recently bought Canon’s EF 200mm f#2.8 prime lens for some deep-sky imaging with the Canon 5D MkII.  To say I am highly impressed with this lens’ performance is a massive understatement – it is fantabulous!

Last night was “first light” for the EF 200mm and I imaged the Double Cluster region and the region around M31.  Note that the field of view is around 9.5 x 6.5 degrees and we have perfect round stars from corner to corner – this is AMAZING performance for a “daylight photography” lens.  It’s certainly more impressive than the refractors I use for the purpose – although at 200mm the focal length is a lot shorter and so the resolution is also quite a bit poorer.  That said – for wide-field deep-sky imaging I reckon this lens takes some beating.

The Double Cluster image was only 6 subs at 3-minutes per sub, f#4, ISO 800, IDAS filter.  The M31 image was just 10 subs at 5-minutes per sub again at f#4 but this time at ISO 400, again using an IDAS filter.

I am highly impressed with the performance of this lens and have a huge list of objects now on the whiteboard waiting to be imaged by this little beauty 🙂 🙂


Arcturus – the brightest star in the Northern Hemisphere

We have just had 8 consecutive clear Moonless nights – I’m pretty sure that one will remain an unbroken record.  Taken during this period of  deep-sky imaging bliss we have the brightest star in the Northern Hemisphere, which is NOT Vega as you might guess (looking up on a summer’s evening Vega appears to be the brightest star up there) – but over to the west, looking a lot like Mars IS the brightest star – and it’s Arcturus.

Arcturus – or Hoku-lea the star of gladness, the star that leads great voyagers home – to quote Stephen James O’Meara in his superb book “The Caldwell Objects”.

There’s something about Arcturus, I don’t know what it is, but I get a great feeling of comfort and security when I see it shining overhead.  Maybe I have some Hawaiian ancestry? 🙂 🙂

Sirius – the brightest star in the night sky:

I managed to acquire the second frame to this Sirius 2-frame mosaic on 1/1/2013.  Hopes that this was a good omen for better weather in 2013 were soon dashed with days of cloud and rain to follow 🙁  Never mind.  Here is a 3.3 x 3.4 degree field of view of the Sirius region taken with the mini-WASP array from the New Forest Observatory.  Processing courtesy Noel Carboni, Florida, U.S.A.