Date: 5th February 2025
Location: Yelverton RAF Harrowbeer old airfield
Equipment: Canon 800D, Zenithstar 61ii, SWSA2i, ASIair mini, ZWO 120mm guide cam, RVO 32mm guide scope
Shooting information: lights - 40 x 120" (1hr 40mins integration time); calibrations frames - x15 of each
Shooting conditions: moon 45%; 3C to 1C without windchill; gusts of wind 15 mph; normal winds 3- 6 mph
Shooting target: M51 Whirlpool galaxy
Post editing: stacked and processed in SIRIL and Affinity Photo
Bands of cloud from the north east were stubborn and slow to clear
It isn't the first time I have aimed my little telescope at this target. I did so last year as well. That image can be seen below:
My first effort at the start of 2024
Not happy with that first go, I went out again later in 2024 and managed to get this image:
My second effort February 2024
There is no doubt in my mind that I am getting to grips with acquiring the data. I am just not spending enough time on acquisition.
However, my post processing skills still suck and 2025 will be the year in which I finally get to grips with mastering the subtleties of Affinity Photo.
So here is my image from the other night:
My latest effort February 2025
This one came at personal cost. It was so cold once you factored in windchill. Although clear skies were forecast from 9pm, it wasn't until 2345 that I was able to get a sustained break in the clouds to allow some continuous imaging.
As the skies cleared, the wind gusts became more frequent. I had to lose about 15% of my lights due to trailing, which was caused by these gusts. My autoguiding , was at times, all over the place, as can be seen on these screen grabs.
The initial steps to guiding went well tonight
On average I was getting around 0.7 on the RA guiding line but frequently I'd get spells like this when it jumped and peaked all over the place
In my beginner's mind, I am putting this down to wind gusts but I can't be sure. Did I not Polar Align accurately enough? I got the green smiley face and my initial PA on the SWSA was pretty spot on. I don't think it was vibrations as I was using anti-vibration pads beneath the tripod legs.
My only other thought is this - is it connected to what I thought might be damage to my clutch system? (see a previous post from a few days ago). I don't think it is, but I cannot be 100% sure.
So what are the basics we need to know about M51?
Co-ordinates: R.A 13h 30m 56.58s Dec +47d 03' 55.5"
Very conspicuous and well known, M51 interacts with a smaller neighbour NGC 5195.
Charles Messier discovered M51 in 1773, describing it as a 'faint nebula without stars'.
The actual whirlpool pattern wasn't seen until 1845 by Lord Rosse through his 6' reflector telescope. Having made a very accurate painting of M51, the galaxy is sometimes referred to as 'Rosse's galaxy' or 'Lord Rosse's question-mark'.
A circumpolar object for most northern hemisphere observers, it reaches its highest altitude in the early morning hours throughout winter and into spring.
You can see M51 through a good pair of binoculars at a dark sky site. It has a bright core and a large faint halo with faint spiral arms.
M51 is comparable to our own Milky Way galaxy in size, mass and luminosity. The spiral pattern is believed to be the result of the close interaction between M51 and NGC 5195, when the latter passed through M51's main disc some 600 million years ago.
The Hubble telescope investigated the centre of M51 and concluded that there existed a black hole surrounded by a ring of dust.
Red light head torches - wonderful invention!
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