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And welcome. Welcome to 'UnderSouthWest Skies'. Thanks for stopping by. I hope you find the experience worthwhile. Meanwhile, clear skies to you. Take care and thanks for visiting Steve aka PlymouthAstroBoy
If you live in the UK, you will be sharing my pain, no doubt.
I mean even if everyone in the universe was buying from one of the country's leading astronomy equipment retailer and so getting one of those 'sticker's, it cannot possibly account for all the cloudy nights we have had this winter season (2024/25). 😂
So, on the 22nd January 2025, I find myself down Bigbury on Sea. According to the app 'Clear Skies' I could get around four hours of clear skies tonight.
As I turn up around 5 ish, I get a lovely sunset - Burgh Island nicely silhouetted in front of a setting sun. And an entire car park to myself, so I park down on the lower level by the toilets.
One of the problems with this venue is the high car parking fee - an astonishing £12 for a long evening session. The other issue is the stupid brightness of the new pay and display screens. They are huge and a major source of light pollution in their own right. But, hey ho, beggars can't be choosers and my Wembury and Dartmoor alternative locations are clouded in!
Target for the night: Barnards Loop around M42 Orion,
Imaging equipment: Canon 800D with 24mm lens prime F/2.8 on a SWSA 2i tracker using accompanying app on smart phone; Benbo tripod, powerbank, intervalometer
Shooting sequence: lights 340 x 13", 40 each of calibration frames; ISO 1600
My aim is to try and gather enough data to get a good shoot of the reddish loop around M42 Orion so that I can then go shoot a separate foreground location somewhere along the coast and then do a composite blend of the two photos via a sky replacement in the landscape shot.
That's the theoretical aim! As a beginner I know reality will be something different 😂
So, what were the environmental conditions on the night? Light north westerly winds, no moon until very late in the night (46%), occasional scattered low level cloud cover, incoming evening tide and temperatures around 1C at midnight. Relative humidity levels around 70%.
The camera lens didn't fog so no dew straps deployed. The polar alignment was precise and I could have got around 60" lights. I didn't because the light pollution glow from Bigbury and Burgh Island seemed particularly horrendous tonight. No idea why but I opted for lots of images to stack at short exposure lengths and an ISO of 1600 which is the best ISO choice for my particular camera. Try as I might I couldn't get the histogram towards the left of centre.
I managed to get around an hour and a half of total exposure time in the end. Scattered clouds came and went, many not showing up above me, so thin was their depth. And then by 11pm, the cloud had thickened significantly and the stars became slowly blotted out, permanently! But they showed up on the images and so, back home, later, I had to delete around a third, if you included ones with satellite and plane trails as well. Hence the low integration time. Very frustrating!
Other things on the night?
I found it difficult to frame Orion and enough space for the Barnard Loop to show using my 24mm lens. Of course, only later I realised my Camera is a crop sensor one - so 24mm is more like 35mm! I'd have been better off using my Samyang 14mm I suspect.
Trailing of stars appeared on around 45 - 50 seconds images. So, I need to find a way of being able to use my autoguiding system (ASIair Mini, RVO 32mm guide scope and ZWO 120mm mini guide cam) with my lightweight set up. I was trying to go light tonight and not use the counterweight bar system. But in future, if on a dark, cloudless night, I want to use autoguiding to obtain far longer exposures, then I need to work out how to arrange it all so that it balances in RA and Dec properly.
That newly acquired polar alignment green laser pen for attaching to the SWSA 2i eyepiece is a 'Godsend'. Wow, does it make polar aligning so much quicker and more accurate when not autoguiding!
What results will I get? I will let you know in a postscript added below at a later date.
PS: the update
Well I have spent ages on this post editing and got absolutely nowhere. And, what is very frustrating, I have no idea what it is I am doing wrong. All beginners will know and understand that feeling.
I stacked all the lights and calibration frames in Siril, before taking the image into GraXpert for cropping, background extraction and denoising. Then it was back into SIRIL for histogram transformation, GHS transformation and using Starnet++ to reduce the stars and stretch the starless image.
It is here that something is clearly going wrong because it just doesn't seem to be removing the stars and reducing them down. Its me not the program and I just don't understand what I am doing wrong as I have used it so many times before without issue!
Anyway, final edits were done in Affinity Photo. I am still trying to learn that program as well 😕
Ho hum, perseverance and persistence are two qualities that all beginners need in any new hobby uptake.
Anyway, not my best effort but here we are: Barnard Loop and the Orion Constellation. You should know that I use an unmodded DSLR camera and so the hydrogen gases wont show up as much I'd like.
Any tips and thoughts as always deeply appreciated. Drop me a comment below and thank you for taking the time to do so.
PS 2
I have been giving some further thought to whether I should be using the autoguiding system I have based on the ASIair mini with my DSLR and small aperture lenses. On reflection, I should be able to easily get 60" - 120" exposures with the SWSA 2i, if, of course, I have done spot on accurate polar alignment. So, next time out I will try for this image again but this time take fewer but longer exposures. Worth a try - see what happens! Will post results here as a further PS update
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