[Alex Pratt]

Hi Dominic,

The video camera will output 25 interlaced frames per second (PAL) and the VTI timestamps each video field, 50 per second. Many occultation (and meteor observers) record to AVI files using a USB video grabber. Limovie and Tangra can read and analyse these at the deinterlaced field level. We use this to get good time resolution (0.02s) on lunar occultations and bright asteroidal events…

https://www.britastro.org/node/8992

The pairs of video fields from an integrating video camera will give (almost) identical images.

UFO Analyser processes meteor AVIs at field level to estimate the meteor’s velocity.

Cheers,

     Alex.

[Alex Pratt]

Hi Tom,

If you are timing lunar impact flashes I guess a timing accuracy of only 0.1s is required to confirm a simultaneous event but researchers may prefer to 0.01s for light curve analysis.

Analogue video at 50 fields per second gives exposures of 0.02s per field, which is the fastest rate currently used by most occultation observers. All these GPS-linked VTIs have an accuracy of 1 – 100 microseconds.

For more information on VTIs and video camera timing delays (internal delays and integration effects) have a look at the work of Gerhard Dangl (AT) here.

Cheers,

     Alex.

[Alex Pratt]

Hi Tom,

Wojciech Burzyński (PL) gave a talk on this at last year’s ESOP in Freiberg. The PDF of his presentation can be found here.

Using a 1PPS GPS receiver module they found that their Arduino-based VTI gave timing accuracies as good as the off-the-shelf IOTA-VTI and GPSBOXSPRITE2 models used by many occultation observers around the world.

Happy assembly!

     Alex.

[Alex Pratt]

Hi Tony,

I have never seen a copy with the set of negative prints. When I visited Skalnate Pleso we were shown their collection of Becvar atlases and catalogues, so I might have been shown a special edition like yours, but I don’t recall it.

Len, the Stara Lesna ESOP was in 2007. As you know I was in Wakefield yesterday, assessing the extent of Melvyn’s collection of star atlas and catalogues. It includes Atlas Coeli and its Catalogue, so we can set them aside for you if you wish. Melvyn’s atlases have a personal touch because some pages contain his pencil sketches of the tracks of comets that he observed.

Clear skies,

     Alex.

[Alex Pratt]

Hi Bill,

Here’s some plots from NEMETODE data showing the detection and extinction altitudes of the meteor family. The geocentric velocity of each meteor shower is indicated by Vg.

I’ll be updating these plots in the New Year with data from 2016-2017.

Clear skies,

    Alex.

[Alex Pratt]

Hi Bill,

The analysis gave the meteor an apparent magnitude of -1.5, as seen from my location. A meteor’s absolute magnitude is its estimated magnitude had it been in the observer’s / camera’s zenith at an altitude of 100 km. This meteor could easily have appeared brighter from your station.

It can be challenging to record meteors with a DSLR. Lens effective aperture and ISO setting are big factors. I have an example of a bright Perseid that was spectacular on my video camera but a much more feeble streak on my DSLR image.

Clear skies,

     Alex.

[Alex Pratt]

Hi Bill,

I think you can conclusively claim this to be a Leonid meteor spectrum.

The attached composite image was captured by my indoor Leeds_N camera, a mag -1.5 Leonid, confirmed by UFO Analyser. The meteor was recorded as it flashed into the RHS of the field of view. The brighter upper trail is the Leonid, the fainter lower trail is an artefact of the double glazing.

Cheers,

     Alex.

[Alex Pratt]

Hi Bill,

just checked my Leeds_N camera. A fairly clear sky from here but I didn’t get your listed meteors. Perhaps David A or Denis B might have them.

Cheers,

     Alex.

[Alex Pratt]

Oops, I was going to attach an occultation report form template, but the website doesn’t support uploading txt files.

Clear skies,

     Alex.

[Alex Pratt]

Hi Richard, William,

Thanks for your confirmations of a miss from you locations.. 

Tim and I haven’t received a positive report, yet. The hunt is still on for the shadow track!

Clear skies,

     Alex.

[Alex Pratt]

Thanks for your report, Lars.

I had good weather and recorded the target field for 5 minutes centred on the predicted time. No occultation was detected from Leeds. I’ll put a summary report on my Member Page.

Hopefully some observers had a positive result to help define the path of the shadow zone.

     Alex.

[Alex Pratt]

The prediction lists the target star as ‘possible double star’. Let’s hope we obtain timings and light curves of this event. Please observe even if you are 100km distant from the predicted shadow zone.

Clear skies,

     Alex.

[Alex Pratt]

Melvyn’s family have now arranged refreshments after the funeral at Wakefield Crematorium. They have provided the following directions:-

 

After the service, guests are invited to make their way to The Milnes Gaskell Function Room which is adjoining Howarth Funeral Services at 125 Denby Dale Road, Thornes, Wakefield WF2 8EB.  Howarth Funeral Services is shown as Thornes Parish Church of Saint James on online maps, but it is the adjacent building.

 

Parking is limited immediately outside the venue but there is parking available at the edge of the park opposite. A road off the roundabout leads up to the Premier Inn and there are a couple of small car parks on the left of the road. People will then have to cross the dual carriageway to get to the function room.

     Alex.

[Alex Pratt]

Sorry Bill, I didn’t record the one at 21:30:14.

Don’t give up hope, because we have a number of video cameras monitoring southern Scotland / Borders and we might have a successful match when their clips have been checked and reported.

Clear skies,

     Alex.

[Alex Pratt]

Hi Bill,

Very nice spectra!

I think I also recorded your Perseid on my Leeds_N camera so I’ll send you my provisional csv file for August – 1500+ meteors so far.

Clear skies,

     Alex.

[Alex Pratt]

I fared much better than last year. I sat outside from 23:00 to 00:30 BST and noted some nice bright long-pathed Perseids in the earlier part of my watch. It was great to see a negative mag meteor streak across the sky then watch it again by replaying it on one of my adjacent UFO Capture PCs.

My provisional haul recorded by my video cameras on the night of August 12/13 was:- 

Perseids

Leeds_N     123

Leeds_NW  182

Leeds_SE   164

not including good numbers of minor shower members.

I’ll put a couple of examples on my BAA Member Page.

     Alex.

[Alex Pratt]

Hi Bill,

I was clouded out at that time.

Always like to see your spectral diagrams, the composite intensity plots and wavelength colour strips are a nice way to present the results.

Fingers crossed for obtaining multi-station orbital data this season.

Clear skies,

     Alex.

[Alex Pratt]

Hi Bill,

I don’t think I’ve ever seen a meteor train distorting whilst the body was still in flight. That’s a great capture.

As discussed offline, my Leeds_N camera wasn’t active at that time. I was AWOL in Cambridge for the weekend, attending the SHA meeting. I don’t leave my indoor system running if I’m away for more than a day. If only the meteor had appeared a day earlier…

Cheers,

     Alex.

[Alex Pratt]

Hi Martin,

Click on the ellipsis “…” to see the full list of names.

Cheers,

    Alex.

[Alex Pratt]

Hi Denis,

I last saw Rob McNaught at an ASE meeting at Calton Hill Observatory in September 2007. Here’s a pic of him and Dave Gavine taken in the Observatory’s reading room.

You could ask Dave if he’s still in touch with Rob.

Clear skies,

     Alex.

[Author]

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