In this Awesome Astronomy podcast extra episode we bring you the key speakers from this spring's AstroCamp in the Brecon Beacon dark sky reserve. As the transit of Mercury was the main feature of this spring's camp, we were delighted to welcome (and now to share with you) speakers with detailed knowledge of planetary transits:

• Dr Rebekah Higgitt lectures history at the University of Kent and former curator at the Royal Observatory Greenwich. Rebekah tells us about the science goals of observing transits, foreign wars, treacherous seas and national rivalries that conspired to prevent observations and the successes and mishaps that befell many astronomers keen to use this method to measure the size of the solar system.
• London astronomer and professional gemmologist, Eric Emms, hosts many public solar and lunar observing events (the next of which will be in London's Regent's Park on June 23rd) and steers Central London's Astronomical Society as a committee member of the Baker Street Irregular astronomers.

  Eric takes us on a voyage to Mercury to show us why this is far from the dull dry world that many may think.