Posts tagged 'Perseid Meteor Shower'

Perseid party-pooper

Posted by on August 13th 2009 in Astrostuff
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According to the weather forecast on Monday, the night skies were to be fairly cloudy on Tuesday and mainly clear on Wednesday. Sadly, it didn't turn out that way. On Tuesday night there were plenty of clear spells during which I managed to sneak out for a quick look around, and there were plenty of Perseid meteors about. I wasn't set up for taking pics, as my camera was off-line due to a sensor-cleaning session. I figured that I could wait another day.

Last night's planned observing session turned out to be a waste of time, as we had fairly comprehensive cloud-coverage here all night. True, there were a few gaps through which the odd trail could be seen, and the clag was thin enough to see when a passing meteor was lighting up the tops of the clouds, but there was no point in setting up the camera.

According to the current forecast there's not much chance that I'll catch the tail-end of the show tonight.

Next year, maybe?

Observing Report 20th-22nd July 2009 (Jupiter and Io)

Posted by on July 24th 2009 in Astrostuff, Observing Reports
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Observing reports have been neglected a bit for a while now while I've being commissioning the observatory. This process has included:
  • Getting the mount drift-aligned so that its axis of rotation is aligned as closely as possible with that of the Earth;
  • Setting up the Shoestring EQDIR to control the mount via planetarium software on the laptop;
  • Setting up the Logitech Cordless RumblePad 2 as a wireless hand-controller;
  • PEC training - measuring the inherent periodic error of the mount gearing to allow the software to compensate for it.
Anyway, Monday night was the first time I'd used the place in anger, so to speak. There had been rain (see here) and there was still a fair bit of patchy low cloud around, but the seeing was reasonably good. I decided to have a peek at Jupiter. It's quite low in the southern sky just after midnight, so there was always going to be a fair bit of atmospheric dispersion to mess up any imaging, and some hazy high cloud didn't help either, but I needed to give it a go to "prove out" the mount alignment and stability. I shot just the one .avi file with the webcam on a general setting, needing the image shape and drift rather than any great detail. Happy that the mount setup was satisfactory, I decided to process the .avi as a check of the webcam's performance. The resulting image is  below:  

Io emerging from behind Jupiter, with Europa a bit further out

I was pleased to have captured Io right on the limb of Jupiter, but I've made a right botch of the planetary processing, which isn't surprising bearing in mind the settings used for capture. Even so, it proved that the webcam is still up to scratch. Given the choice of reprocessing or shooting more video, I went for the latter. The next night I was set up in good time, ready and waiting to take advantage of any gaps in the clouds. There was a particularly clear half-hour during which I managed to shoot eight good two-minute .avis with more specific settings. After the usual software jiggery-pokery, I've managed to get the images from the best .avi stacked and processed reasonably well, certainly better than any that I've done before. Here are two versions of the best stack, the only difference is in the amount of sharpening. Feel free to let me know which one you prefer:

Jupiter and Io version 1 - average sharpening

 

Jupiter and Io version 2 - more sharpening

  Next I've got a different challenge - getting the DSLRs set up on the mount for some widefield shots of the Perseid meteors, which are on show from July 17th to August 24th, with the peak on August 12th. The possibility of getting decent pics all depends on the weather, of course.

Summer Hols – Part 4 – Around Feddet

Posted by on August 29th 2008 in Great Escapes
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Click on any of the pics to open up a bigger version in a lightbox thingy.

The drive out of Copenhagen wasn't as simple as we thought it would be - we had adequate maps and directions, but the roadsigns in the city were sparse and difficult to follow. Eventually we escaped southwards and after a couple of hours we arrived at the Feddet campsite. We were assigned a pitch and soon had our tents (and tarp) set up at the edge of the site right next to the sand-dunes:

 

After going into the nearest town for supplies, we spent the rest of the next day on the beach, which was all of 30 yards away from the tent:

 

In the evening the sky was amazingly clear. I spent a few hours on the beach taking pictures of the Milky Way:

 

The peak of the Perseid meteor shower was still a few days off, but there were plenty on show this night:

 

The next day we headed off inland to visit a few of the local towns and villages. We had a pleasant woodland walk around Nygårds Vænge, a place of trees:

 

lakes:

 

logs:

 

and crisp-eating furriners:

 

Back at the campsite we had a go on the assault-course. Anna took it quite seriously:

 

while Ella used it as another posing-opportunity:

 

while the local squirrel population looked on, unimpressed:

 

In the evening I went back to the beach:

 

and took some pics of the strand-line:

 

Later that night a series of thunderstorms passed by. I couldn't resist the chance to get some pics of the lightning:

 

In the morning we decided to take a walk to the end of Feddet Strand. As we passed the washrooms, I nabbed this pic of a swallow in a nest in the eaves:

 

and another, this time a trio of a different species:

 

Soon we were making our way down the track to the end of the strand:

 

The observation-tower at the end proved to be a disappointment, there being no interesting wildlife there to observe. It did, however, prove to be a good shelter during a short storm. The weather brightened up considerably during the walk back:

 

through the woods:

 

and past more log-piles:

 

During a shower we took shelter in the woods, where there were many toadstools such as these:

 

and this:

 

We got back to the site just in time to have a go at making twist-bread over a wood-fire. Anna was really good at this:

 

The evening was spent in the company of the Baxter family from the neighbouring caravan, where we chatted away and consumed many of their drinks. The next morning we had to pack up and say our goodbyes to them:

 

and to this character, who took a shine to their caravan:

 

Then we were off again, driving to our final campsite at Billund to prepare for our assault on Legoland.

To be continued...

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 – 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.
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