Some observing alerts

The American Association of Variable Star Observers has put out an alert. The Hubble Space Telescope will be conducting an observing campaign, looking at the star M31 V1, the first variable star found in the Andromeda Galaxy by Edwin Hubble. The discovery of this and other variables led the way to determining distances to other galaxies and showing them to be outside of the Milky Way, greatly expanding what we knew the universe to be. V1 is therefore a Cepheid of historical curiosity. Cepheids pulsate with a period that is linked to their luminosity. Measure the period and you can work out how bright it should shine at a given distance away (plus or minus dust effects). The team at Hubble would like some idea of the photometry (brightness) of the star to get an idea of what phase of the change of brightness they’re looking at before they commit the space telescope. This Cepheid is magnitude 19.4 in the sky, making it a very difficult target for all but those with specialist equipment or knowledge. Instructions for ideal observations are in the alert notice here.

A wave of Noctilucent (Night Shining) Clouds has been predicted for five nights starting Monday. NLCs can be seen as waves, bands and ripples shining an hour or so after sunset or before sunrise, when the other clouds are dark. They are polar mesospheric clouds, crystals of ice shining light reflected from the Sun from an altitude of more than 80 km. Observations are requested by BBC Radio 4 to see whether or not this is borne out.

Any meteors seen lately? The twitter #meteorwatch tag now has its own dedicated webpage to display all tweets (even to non-users) related to meteor activity in real time, as they’re written. Any twitter user merely needs to use the hashtag in the normal way to end up in the stream.

And finally, as we all know, you can’t really go out and buy someone a star, just a position in some catalogue no astronomer will ever use. You can however use this webpage, put in a date of birth and find a star whose distance is such that the light we see from it now was emitted on that date in time – a good way to start of a night of astronomy. You needn’t confine it to birthdays, there are other events and milestones you can put an associated date in for, but there is a limit as the nearest star is 4.2 years away.


2 responses to “Some observing alerts

  1. Adrian West

    Very well done mate, I think you need to write a post for meteorwatch

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