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Post by BillW on Dec 12, 2012 12:28:35 GMT
Hi,
After the succes of 2009 I decided to go back on Tenerife to observe the Geminids. Freezing cold last night and very windy. Not much activity but what a fantastic sky!
Testing out my new dslr grating. Gone low tech with cheap plastic grating material but seems to work quite well.
I just hope I actually catch a meteor spectrum with it.
Cheers,
Bill.
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Post by leolion on Dec 12, 2012 18:08:16 GMT
Are you using the 500 l/mm grating roll and the Polish crossed grating technique as here (Zoladec & Wisnieweski) www.imo.net/imc2010/talks/Zoladek_Wisniewski.pdf . It looks to cope with meteors coming from many angles (belt & braces). Perhaps with crossed gratings there could be some Newtons rings effects? Any plain glass support or just held in a frame ? PS A weather report from the Canaries would be of interest  |
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Post by BillW on Dec 14, 2012 0:13:18 GMT
Hi,
It's the same material but only in one direction. I was interested to hear their talk at the IMO conference in Armagh. Given the brightness needed to record a spectrum using a double dispersion element needs even brighter meteors! I prefer to use a single grating in a rotating mount so I can orient the dispersion even if it's not perfect.
As for weather, tonight, as I type at 0009UT 14/12/12 it is perfect here!, +2 deg C, completely clear and light winds.
LOTS of meteors in the past two hours.
Have just caught a -3 ish with a nice sequence of the train being blown in the high altitude winds.
(Unfortunately right at the edge of the field so the dispersion was out of frame so no spectrum!)
cheers,
Bill.
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Post by BillW on Dec 15, 2012 14:50:31 GMT
Hi, The night of the peak was just about perfect. However I got the impression that activity was down a bit compared to previous years. Still I managed to see a couple of hundred over the night. I even caught a faint spectrum, not really useful but a step in the right direction! I've put a video of some of the activity on youtube. youtu.be/VFn3yJZH9-sGot the really bright one still to process. Cheers, Bill. |
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Post by BillW on Dec 15, 2012 16:54:37 GMT
After reviewing the images on a decent screen I think the bright Geminid might have been a couple of mags brighter than I initially thought. Anyway here's the video of it. youtu.be/gabVIJeIqdAMeasuring the displacement of the sharp edge over the first few frames and assuming the height is 100 km (reasonable I hope) I worked out that the wind speed is around 104 m/sec, (that's 232mph), a brisk breeze for sure! Cheers, Bill. |
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Post by BillW on Dec 20, 2012 9:17:02 GMT
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