Archive for March, 2012

Here is a colour and negative B&W version of the on-going Virgo/Coma galaxies mega-mosaic.  Over 4 years in the making so far, this image stretches from M58 in the bottom left hand corner right up to M100 in the top right.  Each image measures 4.42 x 5.16 degrees where the diameter of a full Moon is just half a degree (like the Sun).  The image comprises over 10 individual frames and a total imaging time well in excess of 40-hours.  I will not be taking such large fields of view with the Hyperstar III in future, that’s the whole purpose of putting the mini-WASP array together.  However it is very satisfying to see such a big field of view at the relatively high resolution of 2.85 arc seconds per pixel.

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The Virgo/Coma galaxies mega-mosaic went together a lot easier than I was expecting.  A few tiny bits of extra processing to be done on this one, but here is the negative B&W version so you can scroll around all those galaxies.  Enjoy 🙂

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I managed to get enough decent data last night, despite the sky being full of water vapour and a very intrusive Moon, to fill in the annoying “notch” on the Markarian Chain mega-mosaic.  I have just bolted the last three frames to the main mosaic to check that everything fits together and haven’t bothered with any blending yet.  So there it is – and there it will stay for a while too, I think I’ve just about had enough with this one.  It’s a nice day so I’m going out to cut the grass 🙂

 

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Here is the lower-left hand panel for the on-going Virgo/Coma galaxies mega-mosaic image.  Want to hear some pain?  The Siamese-Twins at the bottom of the image fall off the bottom of the rest of the mosaic by a fraction 🙁 🙁  I don’t think this mosaic will ever come to an end.  Maybe it’s just the beginning of the full Northern Hemisphere sky survey with the Hyperstar III?  I think it might be.

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This is my second attempt at a comet Garradd animation – this time without dithering between subs 🙂  The “jumps” in comet motion are due to lost subs.

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This is last night’s Sky-Watcher data (2-hours) composited with the earlier Sky 90 data (11 and a half hours) – so 13 and a half hours total into this one so far 🙂

 

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I managed to get 2-hours on the Flaming Star nebula in Auriga with the Sky-Watcher Esprit ED-100 quintuplet refractor last night.  Once again, not long enough for a pretty picture, but long enough to check out its performance.  This image comprises 6 x 20-minute subs, I was on sub 8 when the “lost guide star” alarm bells went off as the fog had come down in a big way.  On checking through the subs, sub 7 was already in the fog 🙁  Still – 2-hours of data on a new system is very useful.  Good star colour in the coloured stars, and more to the point – the correct colour.  Good star shapes across the chip, possibly a touch “eggy” in the corners and I expect that is due to poorish Polar Alignment which I am sure is now off quite a bit with all the mucking around with the mount.  The image was taken with the IDAS filter in-line which meant retraining the Robofocus before imaging using Capella as the focus star.  When I had achieved focus I ran CCDInspector and got +0.1″ +0.1″ for the chip flatness in X and Y (which is pretty excellent so I didn’t adjust the camera at all) and when I looked at the collimation it was the magic 0.0″ – perfect collimation – something I had never achieved using the Sky 90s!  The Flaming Star nebula came out well and the reflection region in the centre of the head is pretty clear too.  Not as good an image as in “Star Vistas” taken with the Sky 90 – but then again – the book image was 5 hours and 37 minutes of RGB together with 6-hours of H-alpha so that’s not too surprising.  If I had managed to get 11 and a half hours of good quality data on the Flaming Star nebula with the ED-100 quintuplet I would have ended up with a pretty spectacular image that’s for sure.

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Very lucky to have some clear skies again last night 🙂  Managed to get some imaging done on the Merak region with the new Esprit ED-100 quintuplet refractor.  Two frames here, only half an hour per frame using 3-minute subs, so nowhere near enough subs for a pretty picture, but plenty enough to test out the refractor.

I didn’t spend long enough to get good chip flatness or good collimation, but it was well within the limits I usually pick for imaging.  Stars are a little soft because I didn’t have the IDAS filter in-line, I have only just sorted out the optical train to do that around 5-minutes ago.  Three positives come out of this exercise.  One – no vignetting with their camera adapter!  Good shaped stars corner to corner across an APS size chip.  No lens flare from Merak despite all that glass in the objective.  So they did do their sums right – well done Sky-Watcher!!

I now need to fit the IDAS filter into the train (this might introduce some vignetting due to the way I have to do this) and then I need to image an extended object with some longer subs, hopefully I’ll still be able to see the Flaming Star nebula next outing.

However – so far, so good.

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The utterly superb Sky-Watcher Esprit ED-100 quintuplet refractor is now mounted on the Paramount with the Megrez 80 guide scope piggy-backed above.  I have a Robofocus connected to the ED-100 fine focus knob via a tiny timing belt and actually managed to get the ED-100 focus trained last night before the cloud came in.  For the moment I am imaging through a diagonal (for a number of reasons, including ease of setup).  A 48mm IDAS filter fits to the the 2″ end of the diagonal (the end that goes into the scope, not the camera).  Looking down the business end I think it looks pretty good and I’m expecting any vignetting to be pretty small – but hopefully, we’ll soon see 🙂

 

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When I take a set of sub-exposures of something moving or changing in time I think of creating an animation.  When Dr. Brian May (yes the Queen guitarist) sees a set of sub-exposures with a moving comet and a stationary starry background he thinks of stereograms 🙂  Brian created this totally amazing stereo photograph of comet Garradd using a couple of my time-separated sub-exposures taken recently.  A beautiful piece of work Brian!  Print out the stereogram and view through Brian’s OWL viewer (or an old Weetabix viewer if you have one) or you could even use the “free-view”, or cross-eye technique.  I have spent most of this afternoon just staring at this image with an OWL!

 

 

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