Reference Line maps are used by school children and amateur astronomers in 68 countries throughout the world. The Reference Line Method for locating deep sky objects is a direct, intuitive, graphic method that is not bound by language barriers.

The Reference Line Method requires only common, amateur observing equipment and basic familiarity with the constellations. Bright reference stars can be located in suburban skies. Most beginners learn the Reference Line Method in 20 minutes and are finding objects unassisted within an hour.

We began this project a few years ago with an erasable marker, a star atlas, a straight edge and an irrepressible idea. We were absolutely certain there had to be a better way for amateurs to locate deep sky objects for themselves. Moreover, we were convinced the “better way” would revolve around the latest finding “gadgets”–red dot finders and green laser pointers.

Since releasing these maps to the public in 2009, rapid acceptance among amateur astronomers has quickly catapulted deepskymap.org to the top of search engine results for star charts of Messier objects. Our user base has grown by an astounding 40 % per month for each of the last several months.

What began as a confusing array of erasable lines sketched on an atlas has evolved into computer generated Reference Lines with a multi-variant generation algorithm. Reference Line end-point stars are selected based on apparent magnitude, declination, displacement, and reusability. Intersecting reference lines are produced for each deep sky object. In most cases, at least one of the reference lines can be seen in average, suburban skies. To facilitate usability, at least one reference star is shared between two deep sky objects whenever possible. Maps are computer generated, field tested, reconfigured and retested.

Some use these maps in combination with the Telrad and magnifying finding equipment already mounted to their scopes. Others use them with conventional and digital setting circles. Many use simply a red-dot finder. Compared with methods previously used by amateur astronomers to locate deep sky objects, the Reference Line Method offers many advantages:

1. The Reference Line Method is direct, graphic and intuitive.

2. Light-sensitive peripheral vision is used for viewing Reference Line end point stars.

3. Fogging of finder equipment is not an issue. The intensity of the red dot may be increased if fogging develops. Nothing is actually viewed through the finder but the red dot. Reference stars are viewed around the finder.

4. Red-dot finders are lightweight and inexpensive. Resources that once were used to purchase bulkier and more costly finding equipment may be used to purchase higher quality eyepieces for actually viewing deep sky objects.

Before Reference Line maps, most amateurs used a complicated technique for locating deep sky objects known as “star hopping.” After a few attempts at star hopping, many beginners put their telescopes in the closet to be used occasionally to look at nearby planets and the moon. Convinced that they didn’t have the wherewithal to locate deep sky objects for themselves, when it came time to upgrade their telescopes, many beginners would purchase a computer aided scope with “go-to” capabilities. However, computer aided scopes come with a price. If one is capable of locating objects for oneself, a dobsonian telescope with four times the light gathering capacity can be had for the price of a computer aided telescope.

Our present focus is expanding into the Caldwell List and the Herschel 400. If you are interested in getting involved by contributing your own observations or hosting a star party, contact deepskymap.org@gmail.com.