1186
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General Category / Weather & Atmospherics / Re: Thunderstorm Outlook - Mon/Tues 28/29th
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on: July 29, 2008, 12:57:52 am
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OK Martin, my migraine is just starting so maybe something will happen.
Also the medium level cloud which was around all day cleared up at dusk, but still very hazy, calm, humid & warm but about half an hour ago stratocumulus started forming, a force 4 wind has appeared from somewhere and the temp has jumped from (min) 17.2 to 18.4. No immediate signs of thundery activity though.
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1187
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General Category / Astronomy & Space / Re: Moon, M45, Hyades
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on: July 28, 2008, 09:51:10 pm
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800mm focal length is some job for a camera Wicked isn't it. Actually when the phase is a bit fatter I will happily use both 2x and 1.4x extenders making the focal length 1120mm, or ~1750mm effective allowing for the crop factor on the 40D. My "record" for a straight DSLR shot is using both extenders on the FLT which is 770 mm focal length, i.e. 2150mm actual or very nearly 3.5 metres effective focal length. The half Moon just about fits in the frame, and with careful focusing is really crisp right across the field. Still get more detail with a webcam & Registax though.
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1188
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General Category / Astronomy & Space / Re: Comet Observations 27/8 July
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on: July 28, 2008, 09:44:22 pm
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Any chance you could provide us with a post perihelion image of W1?.
OK, here's the excuses - last night the Moon was in the wrong place - yes, I know it was only a fat crescent, but it would have been a nuisance. And it just so happens that I have a poor East horizon, and it's also in the wrong place so far as local light pollution is concerned, so I would have to go to an alternate site. Which I didn't feel like doing on the first really decent night for a couple of months. Anyway, 2007W1 is getting higher & will clear my obstructed horizon in a couple of weeks. I'll get it before it goes away.
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1189
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General Category / Astronomy & Space / Re: Comet Observations 27/8 July
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on: July 28, 2008, 07:22:59 pm
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Thanks guys. The interesting thing is that I thought I could see 6P/d'Arrest through the eyepiece, but I was sure I couldn't see 2008J1 Boattini. I think Boattini's comets have a curse on me - I seem to be able to image both of them but see neither  2008J1 is clearly well above mag. 10 and ought to be visible.... really well placed just about ten degrees above Polaris, no excuses for bad horizons or twilight please!!!!
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1191
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General Category / Photography / Re: White Rock Beach Sunset
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on: July 28, 2008, 05:56:33 pm
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it would be better being rotated clockwise 1 degree to bring the horizon dead straight. Maybe but the sea up here really does slope - my horizons are always crooked as well (unless I use a tripod and a gridded screen to compose the shot)
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1192
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General Category / Astronomy & Space / Comet Observations 27/8 July
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on: July 28, 2008, 05:16:57 pm
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Here are a couple of images I made of comets last night. These were made with a Canon 5D & 300mm lens working at f/4, piggyback mounted on my 8" LX90 SCT. B+W 491 filter was used to combat light pollution. Sub-exposures registered & stacked using Deep Sky Stacker. The centre of the image has been cropped, making the effective focal length about 800mm. The colour saturation was greatly increased to make the green light characteristic of cometary comas stand out, this means that there is a lot of chroma noise in the sky background! 6P/d'Arrest, 10 x 30 sec exposures between 01:20 and 01:31 UTC 28 July: The comet is only just visible, but the greenish spot indicated is at the exact position according to the ephemeris. I'm fairly sure I've got a capture. Unfortunately thin high cloud was spreading in and I was unable to take more images of this region.  2008J1/Boattini, 20 x 20 sec exposures between 01:35 and 01:59 UTC 28 July. The green glow of the extended cometary coma is clearly visible. 
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1194
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General Category / Astronomy & Space / Re: Moon, M45, Hyades
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on: July 28, 2008, 10:31:57 am
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I looked out at 0400 this morning and saw the Crescent Moon looking rather splendid. You left it a bit late; not only was the sky brightening, there was a lot less cirrus/cirrostratus around an hour earlier. Looks like Autumn's not far away! Cygnus past the meridian, Aldebaran well up in the East, .... Yeah, it comes quick as the 4 mins difference between the sidereal and solar days add on to the rapid advance of dawn.
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1195
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General Category / Astronomy & Space / Re: Perseid Meteor Shower 2008
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on: July 27, 2008, 03:07:13 pm
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this was frame 1 of 37 and was the only one that was any good! Very nice - I like the way the colour varies along the track. There might still be an advantage in using film for meteors - the reciprocity failure means good capture of rapid moving objects but poor capture of sky fog! The Perseids aren't likely to be so good this year as the Moon isn't favourable at the peak Actually not too bad - because the Moon is well South of the ecliptic it sets around midnight even up to the 11th, the pre-dawn period will have next to no interference. Martin - I was up till 2am last night waiting for the sky to clear, no sign - looked out again at 4am when it was getting light and the sky was just beginning to clear 
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1197
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General Category / Weather & Atmospherics / Re: Next Week's weather
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on: July 26, 2008, 07:31:12 pm
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Here's the weekly forecast from the UKWeatherworld... ... FORECAST CONFIDENCE is moderate becoming low-moderate
Here's hoping they got it wrong! Still recovering from Thurs night - got a wee bit of very hazy clearish sky, was out all night trying to observe in shirt sleeves (15C, too warm for a jacket) & got eaten by midges  Too warm to sleep, went for long walk approx. 8 miles round Giants Causeway and was back home at 0610 BST! Too warm to sleep last night, either. A wee bit cooler today so I've been napping hoping for predicted clear sky overnight but it looks very unlikely at the moment.
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1199
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General Category / Astronomy & Space / Re: Friday's rig
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on: July 26, 2008, 01:26:36 pm
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When I was trapped in school during a partial eclipse (May 1966) I rigged a small mirror by the window that projected a pinhole type image onto the opposite wall where I (and the rest of the class) could see it. I don't think the teacher cottoned on.
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1200
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General Category / Weather & Atmospherics / Re: Next Week's weather
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on: July 26, 2008, 01:23:23 pm
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Just my luck! I'm back to work on Monday and it might brighten up!! Have been off since 9th and the weather hasn't been the best. Ah, so it's your fault, is it? Really horrid last night with heavy thundery rain but no actual thunder. Not too bad here today - reasonable Sun with the breeze off the sea, so fresher & more comfortable than it has been for a while. Classic conditions for stratocumulus blight after dark, though.
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