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1186  General Category / Weather & Atmospherics / Re: Thunderstorm Outlook - Mon/Tues 28/29th on: July 29, 2008, 12:57:52 am
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.
1187  General Category / Astronomy & Space / Re: Moon, M45, Hyades on: July 28, 2008, 09:51:10 pm
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.
1188  General Category / Astronomy & Space / Re: Comet Observations 27/8 July on: July 28, 2008, 09:44:22 pm
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.
1189  General Category / Astronomy & Space / Re: Comet Observations 27/8 July on: July 28, 2008, 07:22:59 pm
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 Undecided

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!!!!
1190  General Category / Astronomy & Space / Re: Moon, M45, Hyades on: July 28, 2008, 07:03:45 pm
Here's an image I took of the Moon this morning. I'm linking to it as it's a 1600 pixel square, 172 kilobyte JPEG.

02:28 UTC Jul 28th. Canon 40D, 400mm f/2.8L + 2x extender (800mm), 1/100 sec at f/5.6, ISO 400. Cropped and sharpened (wavelet sharpening using Registax) but otherwise pretty much as it came from the camera.
1191  General Category / Photography / Re: White Rock Beach Sunset on: July 28, 2008, 05:56:33 pm
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)
1192  General Category / Astronomy & Space / Comet Observations 27/8 July on: July 28, 2008, 05:16:57 pm
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.

1193  General Category / Weather & Atmospherics / Re: Thunderstorm Outlook - Mon/Tues 28/29th on: July 28, 2008, 11:47:27 am
North Antrim - Nothing imminent according to my migraine status
1194  General Category / Astronomy & Space / Re: Moon, M45, Hyades on: July 28, 2008, 10:31:57 am
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.
1195  General Category / Astronomy & Space / Re: Perseid Meteor Shower 2008 on: July 27, 2008, 03:07:13 pm
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 Cry
1196  General Category / Photography / Re: A Cold February In Glendalough on: July 26, 2008, 09:18:28 pm
Here is the photo of mt.Ay-Petri near by Alupka (Crimea, Ukraine)
Reminds me a lot of the Wilde Kaiser range in Austria. I bet there's loads of wonderful rock climbs on those walls!
1197  General Category / Weather & Atmospherics / Re: Next Week's weather on: July 26, 2008, 07:31:12 pm
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 Angry 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.
1198  General Category / Astronomy & Space / Re: Jul. 23/24/25 observations on: July 26, 2008, 01:28:44 pm
This year in January I had 10 clear days in a row
OK, how do we go about claiming asylum? Wink
1199  General Category / Astronomy & Space / Re: Friday's rig on: July 26, 2008, 01:26:36 pm
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.
1200  General Category / Weather & Atmospherics / Re: Next Week's weather on: July 26, 2008, 01:23:23 pm
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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