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    Re: Venus in daylight
    From: David Pike
    Date: 2020 Apr 7, 13:36 -0700

    Well we didn’t have to wait until August.  We finally spotted Venus in daylight, and with the naked eye too (not counting my spectacles).  Not that we haven’t spotted it quite by accident in the past, but always while driving, so we’ve never been able to stop and check the Sun still had his hat on. 

    On 30th March I cleared out the caravan and put the Hughes mounting back into the roof to turn it into an Astrovan again.  I was able to calibrate the heading lubber line roughly from where I remembered Polaris used to live.  I was hoping to use the height and azimuth set on my best Hughes periscopic sextant, my Mk2c in service as recently as 1997, more easily despite the eyepiece being only 2x magnification.

     On 31st we were ready hoping to get our first ever Sun, Moon, Venus fix.  Sitting in the caravan was like being on ‘lockdown’ holiday in our own front garden.  Unfortunately, there was too much cloud to see much.  This continued until 4th April when I was able to suddenly spot Venus though a gap in the fair-weather cumulus.  This was enough to calibrate the lubber line properly, but the tea was ready, and I was unable to check the Sun was truly down, because it was behind houses.  Neither did I have my watch nor pencil with me to note the value of Hs, which I immediately forgot once back inside the house.  However, I did manage to use Venus to calibrate my Mk2c on its 30, 20, and 10 degree stops later in the evening against Frank's GPS Anti-spoof app taking ten shots on each stop.  It was interesting to note that the error tended to change slightly over each ten degree range as well as for each stop.

    The cloud in the west situation has continued until tonight and we decided to use our one hour ‘parole’ walk to find somewhere we could watch the Sun set right down onto the horizon.  Standing on the Lincoln Edge at N53.177279 W000.543332 (according to Google Maps), we watched the Sun descending towards the horizon looking in the relative direction I remembered from last night’s values for Venus.  At about 1837 UTC (it was a while before I remembered to check the time), I spotted Venus between wispy strands of cirrus while the Sun’s lower limb was at least two to three semi-diameters above the distant horizon.  After much pointing by me, MrsP spotted it just as the Sun’s lower limb touched the horizon, so one more tick in our 'I spy the stars' book.  DaveP

       
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