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1429 Pemba lightcurve

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  • 12 December 2023 at 12:47 pm #620677
    Wayne Hawley
    Participant

    A plea for assistance.
    As part of the Asteroids and Remote Planet section we are trying to find the rotation period for several asteroids, most of which rotate relatively quickly however this asteroid which is around mag 15 rotates slowly. Until we get a complete lightcurve there is a lot of uncertainty, we currently have two front runners of a little over 400 hours and around 930 hours. During the next 180 hours if its the longer of the two periods we have a gap in the coverage. If you are able to obtain some images of this ateroid with or without a filter and send me the reduced images it will help us to complete the lightcurve. We have observers in the UK, Greece, Luxembourg, USA mainland, NZ and Hawaii.We are also obtaining images from the LCO network and some observers are using remote telescopes. An explanation of what we are doing is in the AARPS page on the BAA website. Images should be about 60 seconds and a minimum telescope size of 10 inch 0.25m to give a good SNR.
    Thanks in advance Wayne Hawley Z09

    Attachments:

    1. 1429-Pemba-possible-light-curve-with-much-longer-period.png

    2. 1429-Pemba-possible-light-curve-with-shorter-period.png

    12 December 2023 at 12:59 pm #620680
    Lars Lindhard
    Participant

    The weather will not permit observations/pictures from the next 180 hours, I’m afraid.

    12 December 2023 at 3:45 pm #620688
    Wayne Hawley
    Participant

    Thanks Lars,

    Weather is a perennial problem for observers.

    Regards

    Wayne

    12 December 2023 at 4:27 pm #620700
    Grant Privett
    Participant

    I have some images I took a few weeks back as a test. I could take some more if the weather clears. Do you want FITS (after dark/flat) or precalculated mags?

    Also, are unfiltered observations okay with you? I assume if I took images on multiple occasions you could derive an instrumental offset? I’m currently using in field stars to derive a Gaia g Zp for each frame and employing tha -though theres a twist to that as I don’t use reference stars that are highly red or highly blue.

    12 December 2023 at 4:49 pm #620703
    Richard Miles
    Participant

    Thanks Wayne for flagging this need.

    A few questions – given we are December 12, can you indicate at what Phase value that corresponds with for the two possibilities?

    Another is the magnitude system used. The plot does not show this. I imagine it is either V, R or G?

    Cheers,
    Richard

    12 December 2023 at 4:55 pm #620704
    Wayne Hawley
    Participant

    Thanks Grant,

    Unfiltered FITS are fine, preferably reduced using dark and flat but if not if you send me the darks and flats I can process them here. I am using TychoTracker so need either the actual images or an ALCDEF export file to add this to the rest of the data. If you email me on hawley.wayne@gmail.com I will send you a DropBox share, or you may have your own method of transferring data.

    Regards

    Wayne

    12 December 2023 at 5:01 pm #620705
    Wayne Hawley
    Participant

    Richard,

    20231212
    For the 927 hour plot we are at phase 0.48
    For the 407 hour plot we are at phase 0.42

    Mag band is Sloan r’.

    Regards

    Wayne

    13 December 2023 at 10:32 am #620725
    Richard Miles
    Participant

    Thanks Wayne – I saw your latest note on ARPS’ groups.io
    This asteroid is well placed for evening sky observation so we should keep observations going over the next month or two at least.

    Richard

    13 December 2023 at 11:15 am #620726
    Dr Paul Leyland
    Participant
    Richard Miles wrote:

    Thanks Wayne – I saw your latest note on ARPS’ groups.io

    As did I. In particular the longer period is now completely ruled out.

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