Category Archives: Deep-Sky Imaging

The stars like dust

This is the first mini-WASP image of 2012 🙂  If you want to know more about the revolutionary mini-WASP deep-sky imaging array then please visit the New Forest Observatory web site.

The accompanying image shows the famous Double Cluster (bottom left hand corner) in Perseus often referred to as “Diamonds on Black Velvet”.  Stock 2 is a very large open cluster towards the top of the image and it looks something like a “stick man” on his side.  I had visions of this image in my mind as I was putting the mini-WASP array together – it helped me get through the rather painful process of building and commissioning the system.  Fortunately the image turned out every bit as good as I had imagined.  There are so many stars in the background to the Double Cluster because the Milky Way passes through this region.

The eye of the Bull







Star name:                                          Aldebaran or Alpha Tauri

Other names:                                      Kugard (Persia), Palicium (Rome),

Constellation:                                     Taurus

Other I.D.                                            HIP 21421, SAO 94027, GSC 1266:1416, 87 Tauri, HD29139

Magnitude:                                         0.87

Absolute magnitude:                          -0.63

Luminosity, Sun=1:                            425

R.A. 2000:                                          04h 35m 55.239s

Dec 2000:                                           +16° 30′ 33.485″

Spectral type:                                     K5III

Temperature:                                      4,010K

Mass, solar masses:                            1.7

Radius, solar radii:                             44.2

Distance in light-years:                      65


The brightest star in the constellation Taurus and forms the “eye of the Bull”.  It is an orange giant star and looks like the Bull’s red eye.  Aldebaran is from the Arabic for “follower” as Aldebaran is seen to follow the Pleiades across the sky.

This image was taken using a Sky90 (90mm objective lens) refractor with a reducer/corrector giving a focal length of 405mm and an SXM25C one-shot colour astronomical CCD.  The image is created from a stack of 21 x 5-minute sub-exposures giving a total exposure time of just 105-minutes.

North America nebula NGC7000 from the mini-WASP array

We have had a succession of clear Moonless nights this past week and this has allowed me to (half) commission the mini-WASP array.  I have found that one of the Sky 90 refractors is quite a way out of collimation and I am working to rectify that.  However, both scopes were sufficiently collimated to get this image of the North America and Pelican nebulae in Cygnus, so this is a 2-framer using the Starlight Xpress M26C cameras and the Sky 90 refractors.  Last night I took a single framer of the very top end of the North America nebula and I will see if I can bolt this image onto the two-framer taken (shown here) earlier this week.

Diamonds on Black Velvet

“Diamonds on Black Velvet” is the description often made when first viewing the Perseus Double Cluster through a good quality telescope – and I do vividly recall the impact it made on me the very first time I saw them through a low power telescope.  The only object with a bigger “WOW!” factor (for me at least) is the Great Globular Cluster in Hercules (M13) – a truly amazing sight.

And the answer is 68,200

A number of people have asked me how many stars appear in the Cocoon nebula 3-frame mosaic?  I have a program called Registar which I use to stitch together separate deep-sky frames so that I can see how they fit together.  Registar also counts the number of stars in an image (I don’t think it is accurate to the single star level 🙂 )  Anyway – Registar says there are 68,200 stars in the Cocoon nebula image with its Milky Way backdrop – so now you know.  One thing is for sure, the number Registar comes up with is always a LOT less than you would guess.

First Light image for the mini-WASP array at the New Forest Observatory

This image shows the Sadr region of Cygnus (the Gamma Cygni nebulosity).  This is a 2,000 second sub-exposure taken using one M26C camera (the other is on its way back to Starlight Xpress today for repair).  No proper drift alignment done yet, so there is a lot of Polar rotation in the image, not to mention hot pixels and dust bunnies – but it is FIRST LIGHT for one of the biggest personal projects I’ve ever undertaken – so a real milestone for me personally 🙂