Friday, 26 August 2016

ISS solar transit - twice in a week

One of the rear occasions, when ISS was crossing the disk of Sun twice in a week time and twice at near perfectly clear sky. From London! :)

For the first one it happened on the 17th of August -  I had to drive up near M1 motorway. I did not have a scope with me sadly, I was working and just took a short break. Luckily I had my Canon 600D and a 75-300mm lens with me. At highest magnification, white light filter, this was the final result.

The second one ( 21st of August) was near Slough, sky was cloudy when I left home, but because ISS was only in a distance of 517 km, I decided to go whatever happens. You need to be in it to win it right :D
So packed up and hit the road. At my arrival to a randomly chosen location along the centerline clouds began to brake up and it was more a lightly scattered cloudy sky.


There was a patch of cloud 2 mins before the transit, but already saw that this might be really good to me as clouds were moving rapidly out of the way and clear spell was following afterwards. About half a minute before the transit it was bright and clear. Capture began and whooops there it was. A quick 0.68s transit.

Happy happy happy times.

Of course the last minute setting adjustment wasn't ideal, I should have had lower gain and higher shutter speed, the final result was a bit noisy. But it all does not matter. Every time I try to learn from my mistakes and let's not forget, an hour and a half before the transit, it all looked doom and gloom, so no room for complaining whatsoever...

Solar arrays are nicely visible

Here is a video about the whole project, the original and half speed transit video, screenshots of the predicted transit using CalSky.

Thursday, 4 August 2016

Mars challenge 2016

Sometime in December 2015 I took a photo through my 200/1000 newton tube, when Mars was still far far away (248 million km away - angular diameter  4.9 arcsec) and it looked like a tiny reddish ball without any surface details.
Then in January I did the same project, only slightly but it was definitely bigger, still a whopping  241 million km away - angular diameter  5.8 arcsec.

Then the idea came, what if I am going to take a shot of the red planet whenever the weather allows me - to capture as it get closer and closer to Earth till it reaches it's closest. Looking back now, weather was crucial part of the project, I had to have a good few weeks of brake due extremely bad weather over UK.

In the meantime I changed equipment, decided to use my beloved 127/1500 maksutov tube with a Zwo ASI 120 MC color planetary camera and a TeleVue 2.5x powermate. Now I had 3750mm of focal length to deal with and it proved pretty useful for this purpose. The planetary camera's region of interest (ROI) was always the same 480x320, this is how I could guarantee the foundation of the proper comparison. 

So the real project started on the 18th of April (2016), Mars was "only" 94 million km away from us and it's angular diameter at 14.2", more than double compare to January. Already showed quite some surface details - I was recommended to use WinJupos to find out what Mars is showing to me at a given time. It worked perfectly and later on, when the red planet was very close I could even identify certain features like Syrtis Major Planum or Olympus Mons. 

Because I used two different tubes at the beginning, eventually I dumped the ones taken with the newton to avoid any confusions. But on this photo the size of the planets are roughly fine, adjusted by basic measurements. 

The shots were taken absolutely randomly as weather was still very unpredictable. But still could manage to take a shot with no bigger gaps then two weeks. Mars just grew and grew all the way to a diameter of 18.6" at its biggest on the 27th of May. 

Clear weather was just one thing, seeing, humidity and jet stream made me run for my money :) I had to wait till the 5th of June for the best of the season. I had the privilege to use my scope and give a try to a Celestron C9.25 SCT too. Here is the result....

Performance comparison of a Skywatcher 127 maksutov and a Celestron C9.25.
WinJupos screenshot in the middle 

From that night here is a link to a gif I have made - gives a bit of a clue what would it feels like seeing any planet over the time as they rotate around their axis...

My plan was to keep doing it as long as possible. Visually Mars looked still very pleasing, definitely to the naked eye, less promising through a scope. So I had to came to the realization that the project is over now. Especially from the UK - even at its highest it was only 16° above horizon - far from ideal. 

Having said that I am very pleased for the result, didn't even dream of having details on a scale like this. This is the final version so far, I might modify it somewhat in the future though :)

As Mars grew and shrank in 2016