THG Networks Presents

Messier MarathonObserver's Log

Track your journey through Charles Messier's iconic catalog of 110 deep-sky objects — galaxies, nebulae, and star clusters — as you race the night sky in a single evening.

What is a Messier Marathon?

A Messier Marathon is a challenge to observe all 110 objects in Charles Messier's 18th-century catalog in a single night. The ideal window is a moonless night in mid-March, when all objects are briefly visible from the Northern Hemisphere. It's one of amateur astronomy's most beloved traditions — from beginners to seasoned observers.

Whether you're attempting your first marathon or logging a lifetime of sessions, MMOL keeps your observations organized, timestamped, and ready to revisit.

110

Messier Objects

Night to Log Them

~8h

Observing Window

Mar

Best Month

Open the Observer's Log mmol.thgnetworks.com

🔭

Log Observations

Record each object with date, time, seeing conditions, equipment used, and personal notes.

🌌

Full Catalog

All 110 Messier objects — galaxies, nebulae, clusters — with type, constellation, and magnitude data.

📅

Marathon Ready

Built for the annual Messier Marathon — track your progress as you sweep the sky in a single night.

📄

Export to PDF

Save your observation log as a formatted PDF — ready to submit for the Astronomical League Messier Club certificate challenge.

How It Works

Pick a clear night — ideally a new moon in mid-March for the full marathon experience.

Open the Log — browse the full Messier catalog sorted by visibility window throughout the night.

Record each find — mark objects as observed, add notes, and export your log as a PDF for the Astronomical League Messier Club challenge.