Archive for August 2007

Watching the Perseid Meteors

Posted by on August 14th 2007 in Astrostuff
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I spent Sunday night and Monday morning outside watching the skies. The weather conditions were good (plenty of cloud-free sky until 03:00) but there was a fair amount of light-pollution to contend with, and the local bat population was out in force too.

Visually, my count (of meteors, not bats) was 124 in about 5 hours, but I could only see about a quarter of the sky from my place. This works out to approx 100/hour, in line with the IMO predictions. They were mostly standard trails that just fade out, but there were some fireballs that were bright enough to cast shadows and which ended their existences with audible bangs. Cool stuff.

I ran off about 200 shots with the Nikon D50, trying various settings, managed to catch a few but the photo quality isn’t too hot, and I didn't catch any of the fireballs. I shot most of the pics in RAW mode, so I was able to enhance/butcher them. Samples are below.

I reckon I'll have to play about with the camera settings a bit more before the next meteor shower. I got my best pics with a manual 30s exposure at max aperture whatever focal length I used (18-55mm zoom, the standard kit lens), ISO 200, all other settings were as per the camera defaults. The main pitfall, I found, is that the camera takes about 25s to save the RAW image after the shutter closes, this takes up nearly half of the available viewing time, and typically the best meteors fizz past while the camera is in save-mode... it's as if the damned things know what's going on, and are determined to be unrecorded. Next time, I'll try using shorter exposures and rely on post-processing to get the image right.

On the bright side (pardon the pun), the ultra-cheapo tripod (given to me by a workmate a few years ago) worked a treat, no shake at all, it's just a tad fiddly to set up with the camera pointing straight up, but that's nothing that I can't fix by knocking up an extension/spacer. The only other thing that would make life easier is a 90-degree viewfinder adapter... I'll try eBay for that, I reckon.

 

 

 

Holiday at home – Saturday 2

Posted by on August 12th 2007 in Great Escapes

Bosworth Park.

It was another hot still day so we started off with a walk around the nature trail and through the woods. The kids had a great time catching grasshoppers and trying to identify the wild flowers and the trees in the arboretum. As evening approached, a good breeze got up so we set up the new powerfoil kites and had fun trying not to decapitate folk who were determined to walk underneath the lines.

 

 

 

 

 

 

 

 

 

 

 

 

Holiday at home – Friday

Posted by on August 10th 2007 in Astrostuff, Great Escapes
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Not so much of a Great Escape today - we've had a lazy day. Besides, the kitchen cupboards were empty, so a shopping trip was in order.

We're currently outside watching the skies - it's the lead-up to the peak of the Perseid meteor shower. We've been counting about 10/hour from our back garden. Here's some info taken from the IMO Meteor Shower Calendar 2007:

Perseids (PER)

The Perseids were one of the most exciting and dynamic meteor showers during the 1990s, with outbursts at a new primary maximum producing EZHRs of 400+ in 1991 and 1992. Rates from this peak decreased to ~ 100 —120 by the late 1990s, and in 2000, it first failed to appear. This was not unexpected, as the outbursts and the primary maximum (which was not noticed before 1988), were associated with the perihelion passage of the Perseids' parent comet 109P/Swift-Tuttle in 1992. The comet's orbital period is about 130 years, so it is now receding back into the outer Solar System, and theory predicts that such outburst rates should dwindle as the comet to Earth distance increases. However, some predictions suggested 2004 —2006 might bring a return of enhanced rates ahead of the usual maximum, and in 2004 a short, strong peak happened close to that anticipated pre-peak time. After that, activity seemed to be roughly normal in 2005, and the moonlit 2006 return was still to come when this text was prepared, but nothing untoward was predicted for 2007 in any case. An average annual shift of +0°05 in the ? of the “old” primary peak had been deduced from 1991 —99 data, and allowing for this could give a possible recurrence time around 9h UT on August 13 (? = 140°16), if so a little after the most probable maximum, that of the “traditional” peak always previously found, which is given above. Another feature, seen only in IMO data from 1997 —99, was a tertiary peak at ? = 140°4, the repeat time for which would be 15h UT on August 13. Observers should be aware that these predictions may not be an absolute guide to the best from the Perseids, and plan their efforts accordingly, so as not to miss out, just in case!

Whatever happens, and whenever the peak or peaks fall around August 13, new Moon on August 12 creates perfect observing circumstances this year. For mid-northern latitudes, the radiant is sensibly observable from 22h —23h local time onwards, gaining altitude throughout the night. The UT morning-hour maxima suggested here would be best-viewed from across North America and northern South America, while the possible ~ 15h UT peak would fall best for Far Eastern Asia.

Visual and still-imaging observers should need little encouragement to cover this stream, but telescopic and video watching near the main peak would be valuable in confirming or clarifying the possibly multiple nature of the Perseid radiant, something not detectable visually. Recent video results have shown a very simple, single radiant structure certainly. Radio data would naturally enable early confirmation, or detection, of perhaps otherwise unobserved maxima, assuming more than one takes place, if the timings or weather conditions prove unsuitable for land-based sites. The only negative aspect to the shower is the impossibility of covering it from the bulk of the southern hemisphere.

We also saw the International Space Station (with damaged Shuttle) pass overhead just before 23:00 - an impressive sight, especially with decent binoculars.

Holiday at home – Thursday

Posted by on August 9th 2007 in Great Escapes

Wicksteed Park.

Yup - it's the place of playground equipment fame. Chris likes this place, so we have to go there once a year or so. It's never too crowded, so there's never too long to wait to get on the rides. As expected, the kids liked the wet activities best. It was another scorcher of a day, we ended up staying late into the evening, playing in the big playground after the rides had closed. Not too many photos, though, as I was shamed into going on the rides myself (I hate going on the damned things - I'm a "feet firmly on the ground" sort of bloke).

 

 

 

Holiday at Home – Wednesday

Posted by on August 8th 2007 in Great Escapes

Coombe Abbey.

After a later-than-planned start to the day we raced down the 10ish miles of back lanes to the Park and had a delightful walk through the grounds and arboretum. This was followed by a long session on the woodland rope thingy and another walk through the woods to the ice-cream van. After walking back through the ornamental gardens we rounded off the day with a picnic in the sun.

Holiday at home – Tuesday

Posted by on August 8th 2007 in Great Escapes

West Midland Safari and Leisure Park.

We hadn't been there for many years, certainly not since before Anna was born, so she was keen to go on the drive-through bit. As expected, she was brim-full of excitement when the animals came really close to the car, but wasn't too chuffed when I locked the windows closed to prevent the ingress of camel-spit and the like. Ella ran off a full 2xAA's worth of pics on her digicam, we've yet to see her pics, maybe I'll add some here late, if I get access to them.

After eats we went off to the leisure park area for fun on the rides. Luckily for us we had picked the one week when the park stays open all evening, so we were able to stay until 10pm and go on just about all the rides. There weren't many folk there - we didn't have to queue for more than 5 minutes for any of the attractions - this was quite a surprise, considering that it was a hot sunny day and a warm evening.

26 pics, click any of the following to get started:

 

 

 
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