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I can’t give you practical advice but I have a background with lasers. Historically many used Invar (Nickel / Iron alloy) rods for laser resonators because of low thermal coefficient of expansion. Many companies switched to carbon composites as lower CTE and much lighter. Found this paper which might be of interest. https://www.researchgate.net/publication/241529927_Long-term_and_thermal_instability_of_carboncarbon_composite
No breach of causality, the relevance of the ISS pass is that they’ll be on way to same orbit so their path will be same (subject to rotation of Earth over 25 min). I did see an unmanned Dragon on way to ISS last July, it was fairly spectacular you could see thrusters firing. Not as spectacular as the 2009 STS128 launch. Watched it live then went outside and watched the shuttle Discovery and its external fuel tank pass over, they’d just seperated.
Managed to obtain a flux capacitor and flared trousers. Heading to 1975 for weekend.
Program looks fantastic.
Perhaps we should all crowd fund a new jacket for Alan for 2021?
It’s the least we could do after the stress he’s suffered!
Hi,
I started off using my ancient Macbook Pro with an ASI120MC-S camera.
I used oaCapture, it is fairly good although I have now switched to Windows and use Firecapture which I prefer.
I don’t know about compatibility with your camera. Suggest you give it a try.
https://www.openastroproject.org/oacapture/
Thanks
Steve
Hugh, I’m just impressed that you had actually measured it. Not surprised though, just impressed! Also very relieved that my guesstimate was not so far off!
Have no experience with the Samyang lens but I have an Opteka 500mm f8 mirror lens and for £85 new on Amazon very happy. 2012 solar eclipse.
The red laser pointers you see are laser diodes, wavelength not particularly well characterised, it varies with operating temperature, ~0.25 nm / deg. I would recommend a green laser, these are normally diode pumped solid state lasers. Wavelength always 532nm, determined by energy levels in Neodymium rather than band gaps in a semiconductor. Blue lasers are diode lasers as well so again wavelength not well characterised. An old style red gas laser would be good, these are Helium Neon lasers, wavelength always 632.8nm.
Nick, you should have been at my “Speed of Light” talk to Newbury in January. I even measured it with some chocolate and a microwave oven. One of my slides is attached. Your statement should be 1802.6175 Gigafurlongs per fortnight!
Total cloud cover was forecast. Outlook seemed better in SE England so at midnight I started driving SE in search of a clearer sky. Found them at Cobham Services 79 miles later. Sky deteriorated quickly, intermittent views, I was taking a sequence of images but clouds intervened about 30 sec before flash. This is at 5.08, 2 sec exposure with 6D using ETX125, the star on the right that has just been revealed by the moon is 7th magnitude HD 67150.
Think if you elminate time dependency, average distance, it’s Mercury.
Closest at some time, Venus.
Steve
Hi Garion,
Picked up the Philips lunar map that Bill mentioned in TheWorks store for £3 about a week ago. https://www.theworks.co.uk/?q=Philips%20Moon%20Map%202018
Steve
Bad luck. Managed to get it. Was going to use a planetary camera but events intervened. Plan B was a DSLR so lousy timing accuracy. All I can say is star was visible at 19:19:04, missing at 19:19:07 and back again at 19:19:10.
Of course it’s just possible they mean the Elizabeth Tower. Big Ben is a big bell but not that big.