Thursday, July 19, 2018

M13 - The Great Cluster

  July 19, 2018    

The unusual run of good weather this summer has resulted in plenty of clear nights recently, but the disadvantage of working away from home is that I have been unable to take advantage of this. However, I now have a couple of weeks off work, so wasted no time in getting the observatory up and running again. This image was captured using a QHY8L and Altair Wave 115ED with 0.79x reducer and field flattener. It is the result of 25 x 180s exposures, captured using Sequence Generator Pro 3, preprocessed using PixInsight and with final processing done in Photoshop CC.

 


The Great Cluster in the constellation Hercules – also known as Messier 13, or M13 – is considered to be the finest globular cluster in the northern hemesphere. It conatins more than 300,000 stars and is 25,100 light-years from Earth.

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Monday, April 06, 2015

The Leo Triplet

  April 06, 2015    

Work has been getting in the way recently so I haven't had much opportunity to get the telescope out, but the Easter holidays has meant I have been at home and the unusually good weather has given us astronomers a couple of relatively clear nights. Whilst the sky has not been completely clear, it was worth having a go at capturing some Deep Space Objects, although the near full moon rising just after 22:30 meant that I didn't have log before sky glow eliminated all but the brightest objects.

After a surprisingly quick setup, considering how many weeks it has been since I have had the scope out, I slewed to the M66 Group - otherwise known as The Leo Triplet. This group of three galaxies is about 35 million light-years away in the constellation Leo and consists of the spiral galaxies M65, M66, and NGC 3628.

The final image is the result of 8 x 300s exposures captured with a QHY8L camera attached to my Altair Wave 115 triplet refractor. The images were captured and stacked using Nebulosity 3 and processed using Photoshop CS6.

The Leo Triplet

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Tuesday, February 17, 2015

Feeling Crabby!

  February 17, 2015    

Despite not feeling particularly well yesterday, the forecast of no moon and a clear sky all night provided an opportunity to test out my new Altair Wave 115 refractor on a deep sky object that could not be missed. So, as the sun dropped below the horizon I started moving my gear outside and setting up for an imaging session.  Once everything was setup and balanced correctly, I selected the Crab Nebula (M1) in Stellarium and slewed the scope to roughly the right location. I then used AstroTortilla to do a quick plate solving routine that established the accurate position of my scope and automatically re-centred on the right point in the sky - I love this software - so much easier than messing about with alignment stars.

Once it was dark enough to start a proper imaging run, I used Nebulosity 3 to instruct my QHY8L CCD to take 15 x 300s exposures, relying on PHD2 to accurately guide my scope through my Starlight XPress Lodestar camera and TS off-axis guider.  I then retired indoors for a nice warm drink, where I was able to monitor the progress via screen sharing on my iMac. Once the session had finished I went back outside and packed everything away.  I then went to bed - I wasn't feeling well after all.

The following morning, I reviewed the images and was pleased that only 1 image needed to be discarded.  I then used Nebulosity 3 to apply the dark callibration frames to the 14 remaining images before stacking. The result was a relatively noise free, although faint, image of the nebula, but most surprisingly, was the flatness of the image compared to those I got from my previous scope - the Sky-Watcher Explorer 190MN Pro.  With the exception of 1 corner, the stars seemed perfectly round across the image and there was no vignetting or background gradient at all.  Application of Neil Heacock's processing workflow, using Photoshop CS6 and Noel Carboni's Astronomy Tools resulted in a very nice looking image, with a stunning array of stars and a lovely structure to the filaments of the nebula. Overall, a pleasing result from my new scope.

The Crab Nebula (M1)
M1 The Crab Nebula - 16 Feb 2015



The Crab Nebula (M1) - Cropped
Cropped version of the same image, showing a closer view of the nebula

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Monday, May 26, 2014

M13 The Great Globular Cluster - Lacking Colour

  May 26, 2014    

Sometimes things don't quite work out as expected. My latest image - M13 The Great Cluster in the constellation Hercules - is the first image I have taken for a while and the first taken using an Off Axis Guider instead of a guide scope. This should have been enough to warn against making too many changes, but I also decided to try out the latest version of Nebulosity 3. I used to use Nebulosity 3 as my camera control software with my Canon EOS, but when I upgraded to the QHY8L CCD it wasn't compatible so I started using EZCap - the software that comes bundled with QHY CCD cameras. However, the newest version of Nebulosity now supports the QHY8L so I thought I'd give it a go and I actually got on really well with it - until it came to processing. I'm not sure what went wrong, but my images seem to lack colour. There is a hint of it in there, but not enough to show the amazing blue and red stars in this beautiful cluster.

M13 - The Great Cluster

The image was captured using my QHY8L camera attached to a Sky-Watcher Explorer 190MN Pro, guided using an Off Axis Guider and Starlight Xpress Lodestar guide camera. It is the result of 10 x 180s images, captured and stacked in Nebulosity 3 and processed in Photoshop CS6. I believe that Nebulosity may have automatically debayered the image prior to saving it to disk - obviously the settings must have been wrong. Whilst it is a lovely image, showing lots of detail in the cluster, I can't wait to try again. Next time I will do a sample run with Nebulosity to see if I can get it working, otherwise I will have to revert to EZCap.

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Saturday, May 24, 2014

Sunday, September 01, 2013

Capturing and Processing Andromeda

  September 01, 2013    

I think this has to be my favourite image so far - captured last night from my back garden using my astro-moddified Canon EOS 1000D, attached to my Sky-Watcher Explorer 190MN Pro. The image is of our close neighbour - the Andromeda Galaxy (M31) - and is the result of almost 90 minutes of exposures (5 x 5min + 30 x 2min), aligned and stacked using Nebulosity 3 and processed using Adobe Photoshop CS6.

The Andomeda Galaxy (M31)
Having initially aligned and stacked the images in Nebulosity 3, I exported the stacked image as a 16 bit TIFF file so that I can process it in Adobe Photoshop CS6 - it is important to remember that at this stage the majority of the finer detail is obscured, so we need to do some tweaking in order to get a nice clean result.

Unprocessed image of M31 after initial alignment and stacking
Without going into too much detail, there are a several stages that we need to perform on this image in order to get it to look like the one at the top of this post. Many thanks to Neil Heacock for sharing his workflow online for others to use.

  1. Adjust levels and curves - effectively, we want to ensure the image is not clipped whilst enhancing the lighter areas of the image so they show up more in contrast to the darker background.
  2. Apply gradient filter - I use Russell Croman's Gradient XTerminator, which is a paid-for plug-in filter for Adobe Photoshop CS6. This basically reduces vignetting in the image that can result in significant colour gradient across the image - especially in the corners.
  3. Apply Local Contrast Enhancement action - this is the first of Noel Carboni's Astronomy Tools for Photoshop. Again, you'll need to purchase these tools, that are effectively a set of pre-programmed actions, but they are an invaluable tool and will deliver excellent results whilst saving you significant time and effort. The purpose of running the Local Contrast Enhancement action is to enhance the contrast between the cloudy elements of the galaxy and the darker dust lanes.
  4. Apply Enhance DSO Reduce Stars action - another of Noel Carboni's tools, this one increases the lighter areas of nebulosity without increasing the brighter portions of the image, increasing brightness without over exposing the stars.
  5. Increase Saturation - this enhances the colour of stars and dust lanes in the galaxy. be careful not to go overboard with this - you do not want the image looking over processed.
  6. Apply Noise Reduction. Another of Noel Carboni's tools - I told you they were invaluable. There are two versions available in his set of tools. Space Noise Reduction (SNR) and Deep Space Noise Reduction (DSNR). SNR will reduce the effect of noise across the entire image, whilst DSNR will leave the brighter areas alone and just reduce the effect of noise in the background. In the image above I used SNR initially, as I had a little noise in the nebulosity, then ran DSNR to further reduce the noise in the background.
  7. Apply the Smart Sharpen filter - if applied to the highlights, whilst filtering the shadow areas, this filter does a nice job of sharpening the detail in the nebulosity and dust lanes without re-adding noise to the overall image.
  8. Apply Less Crunchy More Fuzzy action - the last of Noel Carboni's tools that we need for this image, this adds a little blur to the nebulosity areas, adding the final layer of polish to your image. 

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