500 Best Deepsky Objects

When amateur astronomers talk about the **"500 Best Deep-Sky Objects,"** they are almost always referring to the database compiled by **The Astronomical League** for their **Herschel II** and **Herschel 400** advancement programs, or more specifically, the curated list found in the book *The Night Sky Observer's Guide*.

However, the most definitive "500" list used by modern observers is the **"500 Best Deep-Sky Objects"** compiled by **Glenn Sanner and George Kepple**. This database was designed to be the "Ultimate Bucket List" for any serious observer with a moderate-to-large backyard telescope.

History & Who Made It

The database was born out of the massive research project for the multi-volume set ***The Night Sky Observer's Guide***, published in **1998**. **George Kepple** and **Glenn Sanner** spent years traveling to dark-sky sites, observing thousands of objects, and sketching them to show exactly what a human eye (not a camera) actually sees.

From their database of thousands, they distilled a "Master 500." Their goal was to move beyond the "beginner" Messier objects and the "intermediate" Herschel 400 to provide a list that would take a dedicated observer years to complete.

The Purpose: The "Aperture-Graded" Challenge

The primary purpose of the 500 Best list is to provide a **graduated challenge**. Unlike other lists that assume you have a specific telescope, this database categorizes objects by the aperture (size) of the telescope required to see detail:

• Small (4–6 inch): Showpieces and bright clusters.

• Medium (8–10 inch): The core of the list, including thousands of galaxies.

• Large (12–14+ inch): The "challenge" objects, including faint galaxy clusters and thin planetary nebulae.

It acts as a roadmap for an amateur’s entire "observing career," growing with the observer as they upgrade their equipment.

What Objects Can Be Found In It?

The "500 Best" is heavily weighted toward galaxies, reflecting the reality of the deep sky once you move past the bright stars of our own Milky Way.

The Breakdown (Approximate 500 Total):

• 280+ Galaxies:** Including members of the Virgo Cluster, the Coma Cluster, and famous "groups" like Stephan’s Quintet.

• 80+ Open Clusters:** Selected for their unique shapes and star colors.

• 50+ Planetary Nebulae:** Ranging from the bright "Blue Snowball" to the incredibly faint "Abell" planetary nebulae.

• 40+ Globular Clusters:** Every major globular cluster visible from the northern hemisphere.

• 40+ Bright and Dark Nebulae:** Including "dust lanes" in the Milky Way and star-forming regions.

• 10+ Exotic Objects:** Quasars, supernova remnants, and galaxy pairings.

The 500 Best Deep-Sky Objects (Flat Text Summary)

Catalog Name: The 500 Best Deep-Sky Objects (Sanner & Kepple)

Creators: George Kepple and Glenn Sanner

Established: 1998 (via The Night Sky Observer's Guide)

Total Objects: 500

Primary Focus: Visual observation in 8-inch to 16-inch telescopes.

Object Category: 

• Galaxies: ~285

• Open Clusters: ~85

• Planetary Nebulae: ~55

• Globular Clusters: ~40

• Diffuse/Dark Nebulae: ~35

Famous "500 Best" Challenge Targets:

• The "Deer Lick" Group (a stunning spiral galaxy with tiny companions).

• The Antennae Galaxies (two galaxies physically colliding).

• The ultimate "edge-on" spiral with a prominent dust lane.

• A perfectly circular, faint planetary nebula known as the "Diamond Ring."

Why it is the "Observer's Bible"

This database is respected because it doesn't "fantasize." If an object is a "faint, featureless smudge" in a 10-inch telescope, the database says so. It is grounded in the reality of the eyepiece. For many, completing "The 500" is the equivalent of a PhD in amateur astronomy—it signifies that you have truly learned how to see.

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