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UFO Analyser - Meteor Class

 
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Alex Pratt



登録日: 2012.01.17
記事: 35

記事日時: Wed Jun 27, 2012 4:49 am    記事の件名: UFO Analyser - Meteor Class 引用付きで返信

Dear SonotaCo,

I am testing a 3.8mm f/0.8 lens with my Watec 902H2 for meteor detection. It gives a wide field but I think it is causing me problems with meteor classification.

The 2 attached images are of very similar meteors, but UFOA classes the 231145 event as a 'sporadic' and the 000057 event as a 'flash' or 'noise'. I have tried different settings of the values in UFOA Class but it does not recognise the 000057 event as a meteor.

Is this an occasional problem with using wide angle lenses that give very small movement of meteors?

I normally use my 8mm lens, but another meteor observer has asked me to use my 3.8mm lens.

Many thanks,

Alex.



M20120625_231145_Leeds_Engl_MiP.jpg
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M20120625_231145_Leeds_Engl_MiP.jpg



M20120626_000057_Leeds_Engl_MiP.jpg
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M20120626_000057_Leeds_Engl_MiP.jpg


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登録日: 2004.08.07
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記事日時: Wed Jun 27, 2012 8:36 am    記事の件名: Re: UFO Analyser - Meteor Class 引用付きで返信

Hi Alex
Alex Pratt wrote:
Is this an occasional problem with using wide angle lenses that give very small movement of meteors?

No, I don't think so. 3.8mm f0.8 is a good lens, I am using one.
Measurement accuracy becomes a bit worse compared with 6mm or 8mm lens, but as for zenith direction, it is enough and gives fair results.
(because meters are nearer in zenith direction)

'flash' or 'noise' often happens when some noise or fluctuation is included.
So automated classification sometime requires manual operation to get correct result.
Try something like below.
1. Push 'qm' on the Mask Editor sheet and drag small rectangle around the meteor to exclude noises around, and push 'A' to re-analysis.
2. increase the threshold level 'ddl' (ex. 3 -> 10) and 'A' again to reduce the effect of noise.
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Alex Pratt



登録日: 2012.01.17
記事: 35

記事日時: Thu Jun 28, 2012 3:47 am    記事の件名: Re: UFO Analyser - Meteor Class 引用付きで返信

[quote
'flash' or 'noise' often happens when some noise or fluctuation is included.
So automated classification sometime requires manual operation to get correct result.
Try something like below.
1. Push 'qm' on the Mask Editor sheet and drag small rectangle around the meteor to exclude noises around, and push 'A' to re-analysis.
2. increase the threshold level 'ddl' (ex. 3 -> 10) and 'A' again to reduce the effect of noise.[/quote]

Hi SonotaCo,

Thank you for this advice about meteor classification.

I have tried these options, but it is still classified as 'flash' or 'noise'. One attempt classified it as 'sporadic' but the meteor trail it fitted was incorrect.

It is not a problem for only one meteor. I can investigate this again if I get any more examples during this year's active meteor showers, e.g. the Perseids.

Many thanks,

Alex.
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