Alex Pratt

Forum Replies Created

Viewing 20 posts - 181 through 200 (of 305 total)
  • Author
    Posts
  • in reply to: Welcome to Leeds – light pollution city #583278
    Alex Pratt
    Participant

    Beam me up, Scotty!

    It’s only a temporary art display, but at least Members are aware of it in case it tours the country to ‘delight’ you all.   🙂

         Alex.

    in reply to: Earth-grazer 22Sep2020-0453BST #583171
    Alex Pratt
    Participant

    Hi Stan,

    This object was captured on a few cameras in the NEMETODE video meteor network (UKMON is an independent network based in southern England) and here’s the provisional results from our data recorded by Steve Bosley (Clanfield), Peter Carson (Leigh_on_Sea), Nick James (Chelmsford), myself in Leeds and Jim Rowe (East Barnet). This is its ground track as it travelled from NE to SW (observers in continental Europe recorded the earlier phase of its flyby), e.g. see https://groups.io/g/globalmeteornetwork/message/1366

    The mini-plots show it increasing in altitude and slightly decelerating as it crossed over England. (Its absolute mag. of around -2.7 is the magnitude of a meteor at a standardised altitude of 100 km in the observer’s zenith).

    Our radiant plot, given below, suggests it might have been a Daytime gamma Virginid (GVI), although that shower is not in the Established List in the IAU MDC.

    We obtained a well-defined solar system orbit for the body. The elements have some similarities with a GVI but not fully, perhaps it was a sporadic object. The orbit diagram is here

    Analysis of the end phase suggests the object had climbed to 110 km altitude and was slightly accelerating as it faded beyond detection of our video cameras (when it was moving towards the Severn Estuary). At this altitude the meteor would be leaving the ablation layer. So, we surmise that it had a close encounter with Earth and has lived to tell the tale!

    Such events aren’t uncommon and at the 2018 Winchester Weekend I described the Earth grazer of 2016 July 16 which took 10s to travel 470 km from the North East to the South coast.

    Clear skies,

         Alex.

    in reply to: Life, don’t talk to me about life #583110
    Alex Pratt
    Participant

    As the first interview got underway I wondered if the team had made their discovery using a Sky-Watcher Infinity 76 ‘scope…?   🙂

         Alex.

    in reply to: 2020 Perseid maximum #582995
    Alex Pratt
    Participant

    Thanks Bill.

    Looking at the weather forecast it might be more profitable to listen to your radio system or tune in to the Radio Detection Livestream.

    Cheers,

          Alex.

    in reply to: Historical magnitude estimates of Betelgeuse #582956
    Alex Pratt
    Participant

    Hi Jeremy,

    It wouldn’t be possible to process such a large volume of unrecorded VS observations without the tenacious commitment of these Section members. I’m aware of cases where valuable observations have been lost after members passed away, e.g. by a house clearance or by wiping their computer drives. Thankfully, Melvyn’s family gave us full access to his extensive hoard.

    As I mentioned in VSS Circular 180, the BAA Memoirs contain some useful VS data, but perhaps like in the English Mechanic not all salient information is to hand. Yes, they are certainly worthwhile and rewarding projects to search for old observations and add them to the Association’s archives and databases.

    I’ve promised Roger I’ll write an update for the December VSS Circular.

         Alex.

    in reply to: C/2020 F3 (NEOWISE) #582820
    Alex Pratt
    Participant

    Hi David,

    Here’s an online article with pics taken from Whitley Bay…

    https://www.msn.com/en-gb/news/uknews/stargazers-urged-to-take-in-comet-that-will-not-return-for-68-centuries/ar-BB16Ihl8?ocid=msedgdhp

    I had to laugh when they wrote “Dr Robert Massey, from the Royal Astrological Society…”    🙂

    Clear skies,

         Alex.

    in reply to: Shower Calendar #582631
    Alex Pratt
    Participant
    in reply to: Refocussing meteor cameras #582509
    Alex Pratt
    Participant

    Hi Dominic,

    As William commented, my lenses also have a grub screw to secure the focus of the lens. As you’ll have experienced, focussing is quite a delicate operation with most video camera/lens combinations.

    My Leeds_SE camera sometimes drifts out of focus during the seasons. Often this is an acceptable amount of soft focus, then just as I’m about to shin up the drainpipe it moves back into hard focus again.

    I haven’t tried the masking tape technique. I suspected its expansion and contraction might cause some focus shift. I suppose it depends on the tightness of the rotating bezel.

    Cheers,

          Alex.

    in reply to: Still problems #582347
    Alex Pratt
    Participant

    Thanks Jeremy,

    I can confirm it plays very well from there and Members will find the presentation and discussion most interesting.

    Clear skies,

         Alex/

    in reply to: Still problems #582340
    Alex Pratt
    Participant

    Unlike previous weeks, this evening I cannot view the talk (Jeremy’s) on the YouTube feed. It is working OK for Zoom users. Is it working OK for other YouTube watchers?

    Alex.

    in reply to: Still problems #582336
    Alex Pratt
    Participant

    Hi Ray,

    I found that instead of directly clicking on an option I did right-click and selected Open a new window. This solved my Groundhog Day login problem.

    Cheers,

         Alex.

    in reply to: Strange website behaviour? #582330
    Alex Pratt
    Participant

    I tried to edit my latest entry on my Member’s Page to update the image. On clicking ‘Edit this observation’ – ‘Remove’ I got the error message

    Clear skies,

         Alex.

    in reply to: Website News and Help #582325
    Alex Pratt
    Participant

    Hi Pauline,

    Just click on the ellipsis and you’ll see all names displayed.

    Clear skies,

         Alex.

    in reply to: Gordon Taylor #582315
    Alex Pratt
    Participant
    Gordon was most helpful when I researched HMNAO’s Occultation Machine. I occasionally ‘phoned him to update him on current developments in occultation astronomy and the promise of Gaia’s astrometry.
    Gordon’s autobiography was published in JOA 2016-4 

    An obituary (written by Tim Haymes) will appear in the Journal.

         Alex.

    in reply to: Very bright Starlink train #582314
    Alex Pratt
    Participant
    My Leeds_SE video meteor camera picked up some of these peskies, one clip had 5 of them traipsing across the sky.
    I see that ‘improvements to mitigate the impact on astronomers’ weren’t evident last night. Hopefully the satellites will be fainter when they attain their final orbits.
    The Heavens Above website FAQ says:
    “The brightness of a spacecraft is influenced by several factors…our magnitude estimates should only be treated as a rough guide, and the actual brightness you see could be considerably more or less than this”
    ‘Enjoy’ the show!
          Alex.
    in reply to: Imaging Venus #582266
    Alex Pratt
    Participant

    Hi James,

    Issue 2014-04 of the Journal for Occultation Astronomy (pp. 13-22) contains an article by Friedhelm Dorst on ‘Observations of Planets and Stars near the Sun’.

    We deliberated for some time before deciding to publish it in JOA. We do not condone any attempts to carry out such observations. Observing near the Sun carries high risk to one’s eyesight. It only needs to go wrong once! Even if an observer uses electronic recording techniques, they can be tempted to cast a naked eye glimpse towards the Sun and incur dazzle.

    Be careful out there.

    Clear skies,

          Alex.

    in reply to: observing during the covid-19 crisis #582145
    Alex Pratt
    Participant

    Does ‘stay at home’ mean that we now shouldn’t spend any time observing from our back gardens? Automated systems are an advantage at the moment.

         Alex.

    in reply to: Starlink-3 photobombs 29P #582107
    Alex Pratt
    Participant

    Hi Denis,

    Just wait until Scotland’s Spaceport is in operation and they start buzzing rocketplanes over your head…    🙂

    Clear skies,

         Alex.

    in reply to: Royal Mail stamps issued for the RAS bicentennial #582023
    Alex Pratt
    Participant

    Apart from debating “Whatever did the Romans do for us…” and the varied comments about the artwork, I agree that it’s great to see astronomy on the new stamps.

    If it encourages some youngsters to take an interest in our fascinating hobby / science it will all be worthwhile.

         Alex.

    in reply to: Royal Mail stamps issued for the RAS bicentennial #582020
    Alex Pratt
    Participant

    “He’s not an astronomer, he’s a very naughty boy…!”

    Well, in my astronomical library Messrs Bone, Moore, Sidgwick et al write about aurorae, novae, and supernovae, so after decades of such usage it now grates on my ears to attend talks about ‘auroras’, etc.

    I’ll say tomato…

         Alex.

Viewing 20 posts - 181 through 200 (of 305 total)