Archive for February, 2009

Got my first view of comet Lulin tonight.  Nothing special in binoculars, but looking quite nice with 3-minute subs on the Hyperstar.  Will have to see what I managed to catch tomorrow 🙂

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My son Adam Parker recently graduated with a degree in Journalism and has been writing articles for local newspaper, the Lyminton Times.  In today’s edition there is an example of his work where he describes our recent visit to Sir Patrick at his Selsey home.  Picture courtesy Adam Parker.

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On 10th February 2009 Greg Parker, Adam Parker & Noel Carboni visited Sir Patrick at Farthings to present him with a joint-author signed copy of Star Vistas.  Sir Patrick was in fine form and gave us the keys to his observatories to have a look around.  The big Newtonian reflector through which he did much of his lunar work is in great condition in the “big green” observatory, and the refurbished refractor in the roll-off shed looks superb too.  Sir Patrick wrote one of the Forewords to Star Vistas along with his life-long friend Sir Arthur C Clarke, and “Bang!” book co-author Dr. Brian May.  Thank you Sir Patrick for a lovely lunch and so much of your valuable time – we really appreciate it 🙂

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Noel Carboni flew in from Florida on February 6th to attend the Springer book-signing session on the 7th.  All went well even though the Circle line wasn’t running that day as a last desperate act of sabotage.  Plenty of UKAI forum members showed up – thanks guys!

I then took Noel down to see Sir Patrick Moore yesterday (10th February) and he signed a couple of copies of Star Vistas for us (Sir Patrick is one of the Foreword authors).

After a lightning-quick visit Noel started his return journey to Florida this morning.  I think it was a bit of a shock to Noel having to suffer sub-zero temperatures, flood and heavy snow for the short duration of his visit 🙂

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Good news yet again!!  We got yesterday’s Earth Science Picture of the Day [EPOD] with that amazing variable star lying right next to open cluster NGC7789 in Cassiopeia.  Thank you once again Jim for publishing our work 🙂

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Well – Noel & I eventually made it to AstroFest even though London Transport did its level best to halt our progress by closing down the Circle line today – THANK YOU VERY MUCH for nothing!  Anyway, great to see you all there today, plenty of action and plenty of people despite the recent poor weather (apparently the bad weather made yesterday a bit of a quiet day).

A special big thank you goes out to Springer who have produced a really great publication with Star Vistas, the colour reproduction and the quality are truly excellent!!

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Just heard from Springer that the consignment of Star Vistas books has arrived safely in the U.K.  So it’s all systems go for this coming Saturday.  As I write this Noel is in the air with an ETA of 11:00 a.m. tomorrow morning.

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An eagle-eyed viewer noticed that there were apparently no green stars in the deep-sky images and she wondered why this should be.

Not a particularly easy question to answer, but it is a combination of the characteristics of black-body radiation and the physiology of the eye (colour cameras of course are built to have a similar colour response as the eye – otherwise recorded images, photos,  wouldn’t look too good!).

The blackbody spectrum from hot bodies at different temperatures is continuous from long to short wavelengths, and peaks at a wavelength that is a function of the temperature.  So, if we heat up a bar of steel with a blowtorch it will appear to get red hot, then yellow/orange hot and finally blue/white hot just as it is about to melt.  But it never appears green hot.  We can treat the stars as black body radiators in a similar fashion to the hot steel bar and again we note that the green part of the spectrum, or green stars, are missing.  The reason for this is that due to the continuous  nature of the blackbody spectrum, although the peak wavelength might be in the green region, there is also plenty of emission occuring at the red and blue wavelengths as well.  The eye/brain system “mixes” these colours together so the result is something close to white light (sunlight actually peaks in the green part of the spectrum, but we know that neither the Sun nor its light appear green!).  At lower temperatures we would see a much bigger contribution from the red/infrared part of the spectrum – and as we can’t “see” infrared radiation, the emitting body would appear red.  At much higher temperatures with emission peaking in the blue/violet/ultraviolet region – the emitting body would appear blue as we cannot see ultraviolet light (unless we’ve had a cataract operation and had our organic lens replaced by a plastic one).

So, it is a complex combination of the physiology of the eye (or spectral response of the camera) plus the characteristics of blackbody radiation that leads us to the extraordinary result that we don’t see green stars.

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Noel will arrive in the U.K. this Friday 6th February and we’ll both be up at AstroFest on the Saturday to sign copies of Star Vistas.  Remember this is a unique opportunity to obtain your First Edition copy of Star Vistas signed by both authors as we have no plans to get together in the future for another book signing.  See you in South Kensington this coming weekend 🙂

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February is the latest month I can still image the Orion region, and Orion’s Belt is very well-placed due South for me during February.  The Belt region is full of faint emission and reflection nebulosity that favours dark skies and long integration times for imaging.  The accompanying 2-frame mosaic using the Sky 90 at f#4.5 and the SXVF-M25C one-shot colour camera covers an area just over 4 x 4 degrees.  This image includes not only one-shot colour data, but also narrowband H-alpha and H-beta as well which really sharpens the whole image up.  Total exposure time is in excess of 40-hours and it could still do with plenty more.  Some additional OIII data and R72 (infrared) data would also further improve this image.

There is so much going on here that a very high resolution mosaic using every narrowband filter you have would pay back huge dividends in the final image quality.  You also need to cover quite a large field of view, and my 4 x 4 degrees is rather on the tight side.

Until March 2009 – happy imaging and clear skies!!

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