Alex Pratt

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Viewing 20 posts - 241 through 260 (of 281 total)
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  • in reply to: Leonids 2017 #578781
    Alex Pratt
    Participant

    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.

    in reply to: Leonids 2017 #578776
    Alex Pratt
    Participant

    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.

    in reply to: Double peaking meteors. #578697
    Alex Pratt
    Participant

    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.

    in reply to: Asteroid (6925) Susumu to occult a mag 5 star #578535
    Alex Pratt
    Participant

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

    Clear skies,

         Alex.

    in reply to: Asteroid (6925) Susumu to occult a mag 5 star #578534
    Alex Pratt
    Participant

    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.

    in reply to: Asteroid (6925) Susumu to occult a mag 5 star #578531
    Alex Pratt
    Participant

    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.

    in reply to: Asteroid (6925) Susumu to occult a mag 5 star #578515
    Alex Pratt
    Participant

    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.

    in reply to: Melvyn Taylor #578500
    Alex Pratt
    Participant
    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.
    in reply to: Perseids #578472
    Alex Pratt
    Participant

    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.

    in reply to: Perseids #578465
    Alex Pratt
    Participant

    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.

    in reply to: Perseids #578462
    Alex Pratt
    Participant

    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.
    in reply to: Lyrids 2017 #578168
    Alex Pratt
    Participant

    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.

    in reply to: Lyrids 2017 #578167
    Alex Pratt
    Participant

    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.

    in reply to: Images Likes #577951
    Alex Pratt
    Participant

    Hi Martin,

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

    Cheers,

        Alex.

    in reply to: Rob McNaught’s comets #577929
    Alex Pratt
    Participant

    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.

    in reply to: Transit of Mercury #577369
    Alex Pratt
    Participant

    Clear blue sky all day in Leeds, so one consideration was trying not to get sunburnt.

    I monitored the transit (with my 102mm apo refractor and QHY mono camera) from before first contact up to shortly after 7pm when local rooftops intervened, then quickly transferred to an 80mm refractor set up near the front of the house to follow the last phases. Mercury looked like a tiny ball-bearing in silhouette against the Sun. Seeing wasn’t very good and it was tricky to achieve good focus.

    The resident blackbirds weren’t happy that my presence was stopping them from accessing the birdbath, and some wasps took a long-term interest in my laptop computer.

    The sunny weather brought back happy memories of observing the 2004 transit of Venus from Cyprus – and as I did on that occasion, had a beer at mid-event.

    Cheers,

         Alex.

    in reply to: Aldebaran occultation #577187
    Alex Pratt
    Participant

    Thanks Jeremy.

    I’ve observed a few Aldebaran occultations over the years, with varying success. On 1979 Jan 9 I observed and timed a DD and RB pair, using a stopwatch and time signals. Modern video systems and techniques allow us to obtain much smaller O-Cs than in the days of manual timings, personal equation, etc.

    Clear skies for 2016.

        Alex.

    in reply to: Aldebaran occultation #577185
    Alex Pratt
    Participant

    In recent weeks the weather has been cloudy, cloudy with rain, or clearing and blowing a hooley, so it was a pleasant surprise to have a fairly clear sky and occasional light breeze for recording and timing the D and R events.

    Clear skies,

         Alex.

    in reply to: Joseph Justus Scaliger #577135
    Alex Pratt
    Participant

    Hi David,

    There’s some discussions in past Journals of Scaliger’s work, as documented in the BAA Journal DVD Archive.

    JBAA vol 57 no 3 (1947 March) has a paper by A. K. Bennett on ‘Scaliger J. J. 1540-1609’, but it may not answer your questions.

    Best regards,

         Alex.

    in reply to: Quadrantids 2015 #576777
    Alex Pratt
    Participant

    Hi Bill,

    There will be some uncertainty in the result from Analyser if its profile was created from a small number of reference stars.

    Analyser sometimes categorises a meteor as a sporadic (or other shower membership), giving an unexpected result. Two reasons for this can be the meteor’s angular velocity and its distance from the radiants stored in its internal catalogue. The meteor’s estimated velocity is an important factor and if this falls outside the expected ranges (for each known shower) it can fail the shower membership tests and be categorised as a sporadic.

    Have a look in the UFO Analyser Uty tab and tick the ‘analyzelog’ box. This creates a txt file when analysing a meteor clip. The file contains details about the reference stars, the meteor’s angular velocity and how well it matches against currently active slowers.

    Clear skies,

         Alex.

Viewing 20 posts - 241 through 260 (of 281 total)