Sunday, 27 December 2020

M1 - The Crab Nebula

M1 - The Crab Nebula

In what might turn out to be the last post of 2020, I thought I would round off the year with an effort on M1, The Crab Nebula.  The Crab Nebula is a supernova remnant found in the constellation of Taurus.  It's quite small compared to many other imaging targets, but it's also visible with a decent pair of binoculars or telescope.  The challenge with imaging this particular nebula is to try and tease out the detail within the nebula.  Undoubtedly, a longer focal length telescope will help with this but I need to make do with my 80 ED-R.

I've also made some changes to my imaging set up to try and get the best out of it.  Since I bought the Hypercam 183c, I have just been using it connected to the telescope sometimes with the reducer, and sometimes without.  To get the best out of the camera and telescope combination, I needed to introduce some spacers between the camera sensor, and the telescope.  In theory, this should deal with the 'stretched stars' around the edges of the full frame, in particular the corners.  The correct spacing needs to be very accurate though.  So, I have introduced a 15mm spacer, a variable spacer and a filter drawer into the imaging train.  Bearing in mind, this is the first image with the new spacers in place, I quite pleased with the result, although I think I still need to make some small tweaks with the variable spacer.  That's for another time though.

Finally, before I move onto the image itself, I have also made an experimental change with my pre-processing workflow in PixInsight.  When I first started using the software, I initially used the Batch Pre Processing script to help pre process all my raw light, flat and dark files.  As I got to know and use PI more, I moved onto manually performing the calibration steps to try and achieve better results.  Recently though, I once again have started to struggle with dark from subtraction from my light frames meaning that I am still getting the sensor interference appearing on the right side of the final image.  Since I put my workflow together, numerous enhancements and updates have been released for PI and I now think that there are some additional settings which I need to find out about to help removing this phenomena fully again.  One of the improvements which has been introduced is a new script called WBPP, or Weighted Batch Pre Processing.  Very similar to the original BPP script, it's had some improvements of it's own, so I thought I would give it a go.  I'm really pleased with the result.  The resulting image it produces once again has no sign of the sensor interference.

So, onto the images themselves.  I've produced 2 images of M1.  The first has been processed in PI using PixelMath to help develop the colours of the supernova remnant a little further.  The second image is a cropped version with the background stars removed using he StarNet tool in PI.  Both images were then lightly processed in GIMP.



Finally, thanks to anyone who has given their time to read through my ramblings over the last 12 months.  Feel free to subscribe to my blog if you wish.  You'll get an email anytime I post something.  Have a great and more importantly, safe new year and I will be back in 2021 with more astro related drivel :-)

Thursday, 24 December 2020

My Top 5 of 2020

 My Top 5 of 2020

What a 12 months it's been.  A great year for space science, space travel and amateur astronomy.  2020 has seen some fantastic things happen like the first crew dragon capsule to meet up with the ISS and China performing lunar missions.  It has also seen some sad things like the demise of the popular Arecibo observatory and also courted with controversy with the first formation of a satellite constellation.  But in terms of my astronomy activities, it's been quite some year with unexpected opportunities and other opportunities taken away.  So, in reflection I've put together my top 5 highlights of this, the most challenging of years.

5.  The Pier Goes In

It was long an ambition to get a permanent set up for my kit.  Moving house in recent years provided me with that opportunity, and with the construction of the observatory over a year ago I finally had chance at the start of the year, to get a pier built and put in place.  It was the last piece of the jigsaw which allowed me to get everything set up and in place.  It has proved to be a fantastic timesaver and mean that I can now be switched on an imaging in as little as 10 minutes.


4.  Awesome Astronomy Does Live Streaming

2020 Was full of firsts.  My next highlight was provided by one of those firsts, and that was the live streaming of the Awesome Astronomy recording of one of their podcast episodes.  At a time when people were restricted in what they could do, it provided an excellent distraction from day to day life.  It provided an excellent opportunity to link back into the astronomy community and see some familiar faces.



3.  ISS Solar Transit

Long have I seen images which fellow amateur astronomers have taken of the Sun with a silhouette of the ISS passing across the front of it.  I have always wanted to attempt to capture an image of it myself, but hadn't made time or opportunity to do it.  Towards the beginning of Summer, I did a piece of research to find out when the next transit path was and found that there were 2 transits in the coming days.  The first attempt was a fail.  I just didn't get a quick enough frame rate to capture the image.  The second attempt a couple of days later was almost scuppered by cloud, leaving me no time to get a good focus.  However, I succeeded in capturing my first image of an ISS transit.


2.  Dither

It seems an odd choice, at first, to call this a highlight of my year, but I firmly believe that learning how to incorporate this into my image capture process has made, and will continue to make, a big improvement to my images.  It wasn't until later in the year, quite recently in fact, that I adopted the technique, so I haven't produced many images at all using the dither function, but it is undeniably well worth doing.  And what's more, it's so easy to do.  This was my first proper image produced using the dither function, and while it's not especially amazing, I am really pleased with it.



1.  Comet Neowise

Without doubt, the big thing which captured the public imagination this year was the first naked eye comet to be widely visible since the 90's.  At a time when we were all being encouraged to take some exercise, but avoid contact with everyone else, Comet Neowise proved to be an excellent opportunity to get out of the house. Even the weather decided to cooperate.  The comet was visible back in the Summer, so it meant that it called for some late nights to be able to see it at it's best.  It felt somewhat adventurous, taking off on my mountain bike at sunset with my camera on my back heading out to a farmers field and then returning in the small hours when all was dark.  But what it lead to was a collection of images which I was really pleased with.



2020 has been full of challenges, and 2021 is going to be much the same, but there is so much to look forwards to.  Clear sky permitting, I shall be taking every opportunity to image and observe as I can this year.  I hope to get back to a star part or two and who knows what else I am going to discover.
Thanks to anyone who has read my blog over the last year, or ever actually.  Have a great Christmas and New Year.  Here's to 2021!

Thursday, 17 December 2020

NGC 7331 - More than meets the eye.

 NGC 7331 - More than meets the eye.

Greetings!  Sitting here listening to the latest Awesome Astronomy podcast, it's time to put fingers to keyboard and put together a post about my most recent image.  In truth, I wouldn't post this image normally.  It's quite poor in quality because of the conditions that the data was gathered in.  The night of the image capture was back at the start of November when the initial dark sky quality was not too bad, but as the evening went on the sky filled with a thin mist until a point where the only starts visible were at azimuth, directly overhead.
My target for the night was NGC 7331, which I picked out of one of my astrophotography books.  Also known as Caldwell 30, it is an unbarred spiral galaxy in the constellation of Pegasus.  So, why did I decide to post this image anyway, despite it overall being quite poor.  Well, when I started looking more closely at the image, I realised something which I hadn't appreciated when I first chose the target and that was the number of galaxies that could be seen in the image in poor conditions with just 3 hours of exposure and a small 80mm refractor.  
At a relatively quick glance when zoomed into the image, I picked out at least 24 other galaxies, aside from the main target in the centre of the image.  To help point them out, I have added red lines pointing at each galaxy or galaxy cluster.  It's amazing to think that these are just the ones I can see at a glance.  The numbers of galaxy in the image's field of view probably is much more.


In case you can't see the galaxies pointed out, I've taken zoomed in image snips of many of them to illustrate what's visible in a full resolution image.  Perhaps my most favourite one is the last but one image which shows a perfect face on spiral galaxy in which the arms of the galaxy can clearly be defined.  In the main image, it's in the bottom right corner.


















So, an image and a post more for posterity than publishing on the blog, but it's a great reminder that when imaging, it's always worth having a scout around to see what else is lurking around the main target.