An evening with Prof. Brian Cox

A pretty amazing thing happened in Manchester last night; 12,000 people filled the MEN Arena on a Saturday night, not to see a band, but to watch a physicist talking about astrophysics, the origins of the universe and the likelihood of life on other worlds. And I was one of them!

I missed Brian Cox’s last tour and immediately kicked myself for not bothering to grab a ticket so, last February when a new tour came around, I immediately bought a couple of tickets and began to make plans. We booked the hotel pretty sharpish and then quietly forgot all about it until just after Christmas when we both realised that it was only weeks away.

And so it was we joined an army of other geeks, physicists, and the just plain curious in filling Manchester’s premier concert arena to watch Brian Cox play his home town. And boy did he not disappoint. The night was a strange blend of lecture, comedy and pathos that had me gripped for the two plus hours Brian and Robin Ince (his co-presenter on The Infinite Monkey Cage spoke. The show was slick in its presentation and effects however Cox cut through all that, his gently spoken delivery begging for attention and understanding. The content was delivered at all levels, satisfying the keen amateur right through to the astronomer and dabbler in astrophysics I like to think I am.

We left with our heads spinning with new ideas and concepts – how likely was it that there is life on other worlds (statistically very high) and how likely is it that this life will be complex and living in civilised (sadly, a lot less likely). The message that came across strongest for me was that, empirically, there is only one civilisation in the Universe and we are it. We are fragile and, if we are to survive, we need to cut through all the crap we see in the world today in terms of greed and selfishness, and start to think of our place in the universe as a whole. We may be the only civilisation the universe will ever produce and that makes us special. It also beholds us to protect what we have before we disappear quietly into the void.

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Jupiter May 2018

Jupiter has just gone passed opposition which made it perfect for imaging. Also, from my backyard, it was in prime position between the trees, above my neighbours’ house. With so much deep sky imaging, it is easy to overlook the bodies in our solar system, and Jupiter is an ideal candidate for even beginners to have a go at.

One of the challenges to imaging Jupiter, particularly at the minute, is that it is relatively low on the southern horizon in Britain (just above 30 degrees). Combined with it rising at dusk, this means poor seeing caused by temperature currents affecting the atmosphere. Imaging through these disturbances means that the target will appear to go in and out of focus rapidly. This is further exasperated by the magnification of your scope. One way around this is to use ‘lucky imaging’, a system whereby you shoot high FPS (frames per second) video that you then stack using software to reduce noise, as well as reject all but the best frames.

Due to it’s rotation, I limit my videos to 90 seconds at a time so I am typically gathering 3,000 – 5,000 frames per video. With several such videos taken in rapid succession, I typically process around 20,000 frames to stack into my overall image.

Before moving onto Jupiter, I focus using a bahtinov mask on a nearby star (Arcturus works well for me). Once I am focused, then I know that Jupiter will also be well focused, even if it is slipping in and out of apparent focus due to the seeing. Yes, people will argue that stars are hugely further away than Jupiter and so technically they are not in the same focus plane however the actual differences on my scope would be measured in nanometres and so is irrelevant.

I image using Sharpcap as it enables me to gather .ser videos rapidly as well as name them how I wish. This step is important as I want the filenames to contain the universal timestamp of when they were captured as I need this information for later on in WinJupos.

I tend to drive the camera gain quite high to allow the FPS to be as high as possible. This will create noise so it is a balancing act, and also this noise can be mitigated to some degree in stacking as well as post processing.

I ended up with 6 x 90s videos which I then loaded into PIPP for alignment. PIPP allows me to crop the video down to the size needed as well as do some basic pre-processing such as weight each frame by quality. I then loaded the saved videos into Autostakkert!3 for stacking. I know this might look like duplication as I also use Registrax later in the process, however I prefer using Autostakkert!3 as it is 64bit and can use all my machine’s cores.

In Autostakkert!3, I stacked each file, rejecting 90% of the lowest quality frames. The remaining 10% were then automatically stacked and saved as a TIFF file. From here, I loaded it into Registrax for processing. I first of all aligned the RGB as my planetary camera has a RGGB matrix so the videos tend to be green before processing. Once aligned then I moved to wavelet sharpening. This allows details to be drawn out on different wavelet (resolution) layers, along with noise reduction of the same layers, This is a real ‘trial and error’ for me, however this tutorial does a great job at introducing the concept of wavelet sharpening.

Finally, I save the image down and move to Photoshop for saturation and final noise reduction. And the image is complete.

My equipment:

Altair Astro Hypercan 178c
Skywatcher EQ6-r Pro
Skywatcher 130pds using a 2x barlow

Jupiter May 2018

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NGC 7023 Iris Nebula

Finally, some more clear nights with an almost moonless night. After my last successful outing on the Pinwheel Galaxy at the end of April, I was keen to complete at least one more LRGB image before we lose astronomical darkness for the summer. I attempted Iris Nebula last summer but a lack of ability along with inclement weather meant I failed badly on it. It is still early in the season for this nebula as it remains low in the north eastern skies, however this allowed me to complete 3 clear runs without meridian flipping so it was worth the gamble.

I imaged over three nights, gathering 6 hours of luminance and 3 hours total of RGB data. The exposures were all on gain 0, offset 10, captured on my QHY163m using Sequence Generator Pro v3.

Lum: 75 x 300 secs
LRGB: 30 x 120 secs per filter

Again, I used Astro Pixel Processor to stack and calibrate the subs. I really love this program now I have got used to it. Its ability to remove light pollution gradients, in particular, is superb. I really must get around to completing a review and tutorial on how I use it.

The stacked and calibrated subs are then moved across into PixInsight for processing and combining. I wanted to try and bring out the dust lanes around the nebula, as well as keep the star and nebula colour vibrant without over-doing them. I think I have found a balance here – one I am happy with at this stage anyway. I started to use more complex methods of bringing out the dust using wavelets layers however I found I need more practice with these before I am competent in using them so I stuck to my usual masked stretches, a wide range of star, nebula and bright object masks, and then little adjustments until I reached the final image.

I am a lot happier now with my LRGB process, especially given the skies I have to deal with. The use of a CLS CCD filter in addition is, to my mind, a sensible step to take in order to block out unwanted light polluting light frequencies before they ever hit the sensor. Others disagree, but that’s half the fun of imaging.

Unless I have more clear nights very soon, it’ll be on to narrowband emission nebula until August when we get astro darkness returning in the UK and, with that, Andromeda!

The Iris Nebula -NGC 7023

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