Episode 89In this episode of the Observers Notebook podcast, host Tim Robertson talks to comet discoverer, Don Machholz. Don discusses the history and how to do a Messier Marathon. You can contact Don at:[email protected]Don’s Comet website:http://donmachholz.com/All Arizona Messier Marathonhttps://www.facebook.com/groups/241449202936274/For more information you can visit the ALPO web site at:www.alpo-astronomy.org/You can join the ALPO here:https://store.astroleague.org/index.php?main_page=product_info&cPath=10&products_id=39You can also support this podcast at Patreon:https://www.patreon.com/ObserversNotebookListen to the podcast on Soundcloud:https://soundcloud.com/observersnotebookSubscribe on iTunes:https://itunes.apple.com/us/podcast/observers-notebook-the-alpo-podcast/id1199301885?mt=2I want to thank the Producer of this podcast, Steve Siedentop for his generous support of the Observers Notebook.