Nick James

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Viewing 20 posts - 561 through 580 (of 946 total)
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  • in reply to: Christmas Meeting #581743
    Nick James
    Participant

    Thanks. I just hope Elon Musk was not watching…

    in reply to: Spectra of old novae #581740
    Nick James
    Participant

    I heard you mention this during your acceptance yesterday. Amazing stuff.

    in reply to: Christmas Meeting #581739
    Nick James
    Participant

    Thanks all for the feedback. I think it mostly worked well. With the support of the IoP we hope to be able to do this for all our London meetings from now on.

    in reply to: gb00234, a bright interstellar comet? #581680
    Nick James
    Participant

    Before 2I all of the comets that we know with very slightly hyperbolic orbits acquired the extra velocity through planetary perturbations when they were in the inner Solar System. We would expect comets falling in from the Oort cloud to be in parabolic orbits, i.e. have a velocity of zero at infinity. The largest eccentricity known prior to 2I was 1.057 for C/1980 E1 (Bowell). This large excess velocity (around 3.8 km/s) was acquired  from a Jupiter encounter in 1980 December. Comet C/1956 R1 (Arend-Roland) had an exit eccentricity of 1.0002. The pre-perihelion eccentricity was indistinguishable from parabolic. The ultimate end for our comets is to either fall into the Sun or be ejected from our Solar System and become an interstellar comet for some one else.

    in reply to: An independent discovery of Neptune ? #581674
    Nick James
    Participant

    At least when Peter Dunsby discovered Mars (AT 11448 here) he was presented with a nice certificate.

    in reply to: An independent discovery of Neptune ? #581673
    Nick James
    Participant

    As you say, that’s minor planets. Perhaps we should send them a link to Dominic’s site: https://in-the-sky.org/data/planets.php

    in reply to: An independent discovery of Neptune ? #581670
    Nick James
    Participant

    Seriously, if an amateur did this they would be crucified although at least we are trusted to post discoveries on TNS. We are not allowed to post to The Astronomer’s Telegram since we can’t be trusted to get things right on our own. I’d be interested to know what checking the MASTER team do before posting their discoveries. Checking for moving objects like asteroids and planets is pretty basic stuff. It would be nice to see a comment on TNS from one of the authors explaining what went wrong but so far nothing.

    in reply to: A meteor trail? #581663
    Nick James
    Participant

    Possibly. It could have been an aircraft I suppose but the faint residual image in the next frame looks like a decaying train.

    in reply to: An independent discovery of Neptune ? #581660
    Nick James
    Participant

    Well done them. You’d have thought that one of that almost infinitely long list of authors might have checked…

    in reply to: Balloon-borne meteor video observations #581650
    Nick James
    Participant

    That sounds like a fun thing to do although recovering your expensive kit might be challenging. There are rules about launching high altitude met balloons in the UK and a useful FAQ here in case anyone wants to have a go.

    in reply to: Prediction of high activity of alpha Monocerotid shower #581628
    Nick James
    Participant

    Rotten weather here in Chelmsford although my cameras caught a few meteors last night during short gaps in the cloud. There were only small gaps in the cloud at the predicted time of the storm and nothing was picked up then.

    in reply to: Transit of Mercury #581565
    Nick James
    Participant

    At 13:47:19. Is it an MD-11?

    in reply to: Transit of Mercury #581561
    Nick James
    Participant

    Lots of showers this morning and a load of clouds around. The seeing is awful and it is blowing a gale but I was lucky at first contact here in Chelmsford. Here is a frame from my video taken at 2019-11-11T12:37:33.

    Here’s the animated GIF of first and second contact.

    in reply to: 1998 HL1: upcoming fly-by #581538
    Nick James
    Participant

    David. Excellent. I can breath easy now.

    in reply to: 1998 HL1: upcoming fly-by #581527
    Nick James
    Participant

    Yes, 13.4 tonight and moving along at almost 18 arcsec/min.

    in reply to: 1998 HL1: upcoming fly-by #581521
    Nick James
    Participant

    Here’s a quick animation I obtained tonight while waiting for it to get dark. These are 10s exposures. 33×22 arcmin field, N up.

    in reply to: 1998 HL1: upcoming fly-by #581499
    Nick James
    Participant

    That is a lot of objects to track and control too.

    in reply to: 1998 HL1: upcoming fly-by #581497
    Nick James
    Participant

    Thanks. Here’s a short movie taken a little later when it had cleared up. Still a very bright Moon in the sky.

    in reply to: 1998 HL1: upcoming fly-by #581495
    Nick James
    Participant

    Thanks for the reminder. That’s a great movie. It is cloudy here in Chelmsford at the moment but I did have a few gaps earlier and caught the trail. It is currently around mag 15.3 moving at 7 arcsec/min.

    in reply to: Non-Windows stacking software. #581462
    Nick James
    Participant

    https://openphdguiding.org/man-dev/Tools.htm#Comet_Tracking

    Although I have never used this myself…

Viewing 20 posts - 561 through 580 (of 946 total)