graemehowie.com

International Space Station Visual Pass

That’s right folks, I’ve been playing at Astrophotography with my new Canon EOS 450D, and the past few days the International Space Station has been particularly bright. The image was recorded over a 20 second exposure, not ideal as the star trails are obvious, but for a first attempt I’m quite satisfied. Once I’ve worked out how to do multi-image align and stacking I’ll have a go at that.

The site Heavens Above is a good resource to find out when the ISS will be visible, as well as the fascinating Iridium satellite flares, which are apparently visible in daylight.

It’s odd standing there looking at the ISS cross the sky knowing that it’s travelling at over 17000 miles per hour, and is less than 500 miles away.

More of my beginners astro-images are in the Gallery but for some really great pictures look at Astropix.com

I’m still thinking about buying a telescope! At least it’s not so cold at the moment. If I can make it till October, that will be 10 months of thinking, and that’s usually a good sign that I won’t get bored too soon. It’ll be cold out again by then though…

We’re off on the boat tonight for a second attempt at a ski trip to Scotland. Predictably, the weather forecast is for storms!

However, at least this time we’ll have our own skis – well, hopefully. Catherine’s skis were delivered last month, but as the shipping cost for mine was an unbelievable £50 (!) they were delivered to my parents house instead. Catherine’s only cost £10 to ship. Anyway, if they fit in the roofbox, I’ll have my own skis too.

In preparation for the big snow falls (snigger) I decided to get some new tyres on the Freelander. The original front tyres lasted an astonishing 47000 miles, and the rear pair are looking good for 50k. No surprises that I ordered the same type again. (Michelin Synchrone Extra Load 215/65R16). I’ve left the new ones on the front for the ski trip, but they’ll be going on the back afterwards – the Freelander drives the front wheels slightly faster than the rear, and the circumference difference of having new tyres on the front and old on the back increases the speed differential the viscous coupling has to deal with, and may cause early failure.

Anyway, we’re heading up to Aviemore on Sunday, then probably down to Fort William on Wednesday. If the weather plays the game, we should hopefully get a chance to visit Glencoe too, never skiied there before.

I started looking at celestial navigation as a result of wanting to recreate a transatlantic flight in FlightSim without Inertial or GPS navigation systems. There is a simulated bubble sextant available for FS2004, and it works well but doesn’t give you that appreciation of the sky that the real process does. So, I thought it would be fun to try for real. The sextant stuff that is, not the transatlantic stuff…

Two problems: 1 – I don’t own a sextant. 2 – It’s really cold outside.

If you’ve not seen the package “Stellarium“, download it and install it now. It gives you a real time view of the sky, and is fantastic. So good in fact I’ve been considering buying a telescope. (In the summer though: Outside. Cold. Really.)

Stellarium also gives you a display of the Elevation (referred to as Height) of stars and planets. As that is essentially all a sextant does, one can do simulated star shots from any location on earth from the comfort of your living room. The skill of operating the sextant device is bypassed by this, but it does let you practice position fixing.

So all one needs now is a Nautical Almanac and Sight Reduction Tables to determine the expected Azimuth and Elevation for a known (assumed) position. Once the excitement of the Sight Reduction Tables has worn off, the US Naval Observatory has a facility to generate an almanac page for a time and assumed position. A map or piece of graph paper to plot the lines of position completes the navigation kit.

More information on the process can be found at celnav.de, including a comprehensive guide. Once you’ve got your position, you can learn how to navigate to your next waypoint thanks to Ed Williams Aviation Formulary.

I used an old 1:500000 VFR chart and set Stellarium to a random location. (Stellarium can’t set a random location, so one needs a glamourous assistant for this part!). Using the USNO table, I was able to get an accuracy of 1NM when over 45NM from the assumed position. That’s a result in my book!

All fascinating stuff, and I’ll probably buy a cheap sextant to give it a try – on the ground though – Distress & Diversion on 121.5 are a better bet if you’re really lost!

However, should you see someone standing outside on the Ben-My-Chree with a cheap sextant, a VFR chart and a Powerbook (and probably a puzzled look) don’t worry, the boat’s not lost!

Well, just a little bit of snow – Now I was looking forward to Skiing at the end of February, but the problem is the Isle of Man Steam Packet Company have elected to take the Ben-My-Chree out of service for two weeks just when I really need to use it… (The other boats can’t accomodate dogs) Anyway, mid March it is – fingers crossed there will still be good conditions at Cairngorm.

The next two months I’m be mostly snow watching at winterhighland.info!

Well, learning anyway. Satuday 15th December saw Catherine and I doing 1 hour of beginners level 2 snowboard lessons at Xscape in Glasgow. Level 1 was easy, as you stand up pointing up the hill. I found it impossible to stand up facing down the hill (New Year diet required), but once I was up things went well. At the end of the lessons, we practiced proper turns, the idea being to do once half turn and stop. One turn, ooops, two turns, arrgh, three turns. I stayed up though. Catherine naturally assumed this was just me showing off as usual. Catherine’s attempt: One turn, ooops, two turns, arrgh, three turn (she stayed up too). So there! Unintentional showing off.

Anyway, next time we’re in Glasgow we’ll do the 3 & 4 lessons – Linked turns and surface lifts, so fingers crossed for Scottish snow at the start of March and we could well be on real snow, on a real hill. I’ll probably chicken out and go with the skis though!