noah4x4

Hi Gina,

I did a lot of professional public speaking in my career and have couple of thoughts based on what you have said so far.

 Given this audience is not astro people - I think I would first engage their interest by first talking about something they will understand - terrestrial photography. Hence, describe how a DSLR camera works first. Hence; reverse thes two slides

Explain how terrestrial images are typically done with short exposures and how that works fine. Then explain that longer exposures and adjustment to ISO are necessary to capture enough light for evening pictures. Then it is natural progression to quickly explain  how more extreme long exposures (or stacked long integration time short exposures) are needed to do astrophotograpy .  Then mention how daytime images can get blurred if you are trying to capture an image of a fast moving car. Then, only after people have grasped these essential camera basics, explain the rotation of the Earth and the impact that has on long term exposures and the need for tracking and or guiding.

If you offer this same information the other way round, I don't think many in a broad audience will adequately make the link between exposures, earth's rotation and 'star trails'. However, if you reverse this, it becomes a far more logical progression of information. Just my two-pence worth....