Alex Pratt

Forum Replies Created

Viewing 20 posts - 21 through 40 (of 281 total)
  • Author
    Posts
  • in reply to: Bad eclipse viewing advice #622163
    Alex Pratt
    Participant

    I meant to add that I plan to spend a minute or so during totality using my 10x50s to look for the comet (the forum didn’t offer me an Edit option).

    Alex.

    in reply to: Bad eclipse viewing advice #622162
    Alex Pratt
    Participant

    My 10×50 binoculars have travelled the world to several solar eclipses and I intend to use them again to observe during totality on April 8th. The eye and brain perceive the very fine details in the tenuous coronal streamers and the wide range of colour and contrasts in the chromosphere and prominences. Multi-image composite photography gives a representation of this stunning experience.

    Which eclipse travellers plan to image comet 12P/Pons-Brooks during the 4 minutes of totality?

    Alex.

    in reply to: February JBAA #621845
    Alex Pratt
    Participant

    Perhaps overseas deliveries should be in stronger wrappers.

    Alex.

    in reply to: BAA song #621469
    Alex Pratt
    Participant

    The average age at a Winchester Weekend is nearer to 81 than 18, so a bar room brawl is rather unlikely… 🙂

    Alex.

    in reply to: Betelgeuse #621396
    Alex Pratt
    Participant

    Hi Jeremy,

    Tim and I will post an update whenever any results are made available.

    Cheers,

    Alex.

    in reply to: Betelgeuse #621375
    Alex Pratt
    Participant

    Thanks Jeremy.

    Miguel Montarges is the lead scientist of the Leona-Betelgeuse pro-am campaign and he has just e-mailed the group to mention that they’ve received over 100 observations, and 75 of the light curves are almost not – or not at all – affected by clouds. Recordings were obtained using various filters, so they should be able to measure Betelgeuse’s diameter at a range of wavelengths.

    As a very provisional example, Dave Herald measured a light curve obtained in Ha by Alfonso Noschese, and after applying a large limb darkening coefficient it gave a diameter of 60 mas.

    https://ukoccultations.groups.io/g/main/message/3036

    The campaign team also hopes that the dataset will detect the huge convection cells in Betelgeuse’s photosphere.

    Cheers,

    Alex.

    in reply to: 2024 BX1 – Small NEO impact last night #621337
    Alex Pratt
    Participant
    in reply to: 2024 BX1 – Small NEO impact last night #621335
    Alex Pratt
    Participant
    in reply to: Roger Pickard #621064
    Alex Pratt
    Participant

    It is very sad to hear of Roger’s passing. He was a true gent.

    One story I can relate – after the VSS Workshop in Edinburgh in October 2008 I suggested various eateries along the Royal Mile, but Roger gave me a gentle ribbing because every place we checked was full. Eventually, we tried the restaurant at Deacon Brodie’s and they accommodated us with several tables for our group. With a grin, Roger said I had redeemed myself. 🙂

    Melvyn Taylor left a large archive of unrecorded VS observations (thousands submitted by VSS observers and thousands of his own). Roger was a great help in graciously receiving my almost interminable scans of the report forms per star and he coordinated with the small group of data input volunteers to upload them into the VSS database.

    He will be missed by many. My condolences to his family and friends.

    Alex.

    in reply to: Scrapping Honorary Membership ! #620796
    Alex Pratt
    Participant

    I and a number of my contemporaries joined the BAA in our teenage years or our 20s, then as impoverished students our memberships lapsed until when in our 30s or later we had more spare time for our hobby and could afford the annual subscription. None of us are eligible for Honorary Membership and I guess that 50 continuous years will become a rarity.

    Proposals to support younger members – and retain them – are welcomed.

    Alex.

    in reply to: Betelgeuse #620701
    Alex Pratt
    Participant

    Hi Ian,

    Here’s a link to using the drift-scan technique for occultation events

    https://www.asteroidoccultation.com/observations/DriftScan/Index.htm

    I’ve no experience of using it, and the Betelgeuse event was gradual.

    All observers who attempted to observe the Betelgeuse occultation are requested to submit a report form and their raw data to the pro-am campaign team in Paris. This is discussed in Josselin Desmars’ presentation
    (PDF in this link)
    https://share.obspm.fr/s/aYzPBYByoEL2xZY

    (video at this link – talk begins at 1hr 51m)
    https://astrotube.obspm.fr/w/isuxhMSJZ5FNNPKeT3AZbb

    Create an account on the Occultation Portal
    https://occultation.tug.tubitak.gov.tr/

    then upload your report file and data (see other methods if files are very large). The Paris team will analyse your data.

    Alex (back in ‘sunny’ Leeds)

    • This reply was modified 7 months, 1 week ago by Alex Pratt.
    in reply to: Betelgeuse #620663
    Alex Pratt
    Participant

    Even if you cannot avoid image saturation, your data could be valuable. Most setups for this event are configured to monitor the descending and ascending branches of the light curve. A camera that is saturated before the occultation could contribute data on the deepest part of the brightness dip, particularly if it’s >2 or 3 magnitudes.

    Alex (in Alicante)

    in reply to: Betelgeuse #620642
    Alex Pratt
    Participant

    Hi Ian,

    Drift is a good option. Driftscan software can process your capture. Please record for about 1 minute before and after the mid-time given by the Interactive Map of the Paris ‘Lucky Star’ prediction

    https://lesia.obspm.fr/lucky-star/occ.php?p=131608

    Avoid saturation at all costs. If you can’t apply a ‘many-holes mask’ as suggested in the last-minute advice (above), try your R or SII filter with a brief exposure time. A H-alpha would attenuate the light, if available. A small amount of defocus is fine.

    Take darks and flats.

    Good luck,

    Alex (in Alicante)

    • This reply was modified 7 months, 1 week ago by Alex Pratt.
    in reply to: Betelgeuse #620537
    Alex Pratt
    Participant


    On https://www.virtualtelescope.eu/webtv/

    Gianluca Masi, Italian astronomer and developer of “THE VIRTUAL TELESCOPE PROJECT”,
    has posted the following announcement :

    Next event: “Betelgeuse occultation by Leona: live view” –
    12 Dec. 2023, starting at 01:00 UTC

    in reply to: Betelgeuse #620505
    Alex Pratt
    Participant

    A while after 01:00 UT on December 12 Betelgeuse will be occulted by asteroid (319) Leona. It’s very rare for such a bright star to be occulted and this ‘once in a lifetime’ event will be used to model the photosphere of Betelgeuse.

    Recent occultations of other stars by Leona have determined its dimensions, showing that it subtends (perhaps) a slightly smaller apparent diameter than Betelgeuse, giving a partial / annular occultation of 11s duration. The 142 km-wide shadow track passes over China, Turkiye, Greece, Italy, Spain, Portugal and southern Florida (USA), and more than 80 observers are participating in this pro-am campaign. They will record the occultation using various filters and some teams plan to obtain high resolution spectra.

    https://proam-gemini.fr/photometrie-et-spectroscopie-de-betelgeuse-%CE%B1-ori-lors-de-son-occultation-par-319-leona-du-12-12-2023/

    https://call4obs.iota-es.de/2023-dec-12-0110-ut-319-leona-occults-betelgeuse-alpha-orionis-0-5-mag

    Alex.

    • This reply was modified 7 months, 2 weeks ago by Alex Pratt.
    in reply to: Moon occults Venus on 2023 November 9 #620090
    Alex Pratt
    Participant

    Congratulations, David. A bright morning here but too much cloud to make any observations.

    Alex.

    in reply to: Where is the blue dot? #619670
    Alex Pratt
    Participant

    Blue dot marked by a white circle.

    Attachments:
    in reply to: Where is the blue dot? #619663
    Alex Pratt
    Participant

    See the attached cropped image from the PDF version of the latest Journal.

    Alex.

    Attachments:
    in reply to: C/2023 P1 #619134
    Alex Pratt
    Participant

    Incomplete hyperlink – just copy the whole line and paste it into a browser

    in reply to: Preparing for the eruption of T CrB #619097
    Alex Pratt
    Participant

    During the webinar, the speaker repeated that “…T CrB will soon be the brightest nova in living memory…at mag 2…” Someone commented in the Chat box that Nova Cyg 1975 (=V1500 Cyg) reached mag ~1.7. (BAA VSS database ~1.5).

    Perhaps he meant the brightest known recurrent nova.

    Many observers enjoyed seeing the ‘new star’ in Cygnus in August/September 1975, including myself, and I look forward to observing T CrB in outburst.

    Alex.

Viewing 20 posts - 21 through 40 (of 281 total)