Dark Sky Observing Sessions

What is a Dark Sky Observing Session?

A dark sky observing sessionA dark sky observing session is a more formal event for club members and our guests. Formal in this instance means that people attending are often doing their primary observing, and often have lists of specific tasks that they will be accomplishing. All of this is done under a beautiful dark sky, away from city lights and noise. The conditions allow observers to see dimmer objects than they can in the city, therefore making it a perfect time to pursue observing certifications offered by the Astronomical League.

NEFAS holds two (three when moon phases allow) dark sky observing sessions every month on the Saturdays closest to third-quarter and new moon. Since moon phases change throughout the year, please check our event calendar to find out the exact dates and times. These sessions are held at an open spot in the Osceola National Forest, north of the town of Sanderson. From the Marietta exit of I-10, it is approximately a one hour drive to the dark sky site. Several maps to the location are provided at the bottom of this page.

Dark sky observing is a very enjoyable opportunity for astronomers. The term “dark sky” refers to the seeing conditions at the site. From our vantage point in the Osceola National Forest, we are removed from the direct effects of city light pollution and are treated to unobstructed views that stretch from treeline to treeline. With the country as densely populated as it is now, many people have never seen a truly dark sky. The number of stars and other objects that become visible away from the city glow is truly amazing.

Who Can Attend a Dark Sky Session?

We welcome everyone at our dark sky observing sessions. You do not have to be a member, nor do you need to own a telescope in order to join us. There are plenty of friendly NEFAS members available who will be happy to share views with you.

Because of the nature of our dark sky sessions, however, it is not quite the same as our public sessions at Hanna Park. For many reasons, a dark sky session is probably not the best time to get assistance with a telescope. Many of our members use these sessions are their primary times to do their own personal observing, so they may not be as available to assist you. Several members also do astrophotography at the dark sky sessions, and they are focused quite a bit on their tasks.

All this is not to say that our members are any less friendly or accommodating during dark sky observing. We just ask that you respect those people who are there to accomplish their own personal observing tasks.

How Do I Get There?

We refer to the dark sky site as the Swamp. It is in a fairly remote location just north of the town of Sanderson in the Osceola National Forest. There are maps at the bottom of this page that will help you find it. If you don’t want to try and find it on your own, post on the NEFAS Facebook page at least four hours before sunset that you would like to follow someone to the site. A NEFAS member will respond with a time to meet you. The meeting place is the Firehouse Subs at I-10 Exit 335 – SR 121 North (South Sixth Street) by the Winn-Dixie. The address is 1448 South Sixth Street, Macclenny, FL 32063. You can follow the member from there to make sure you find your way to the Swamp observing site.

About the Location

As we stated earlier, the dark sky site is in the middle of the Oscola National Forest. The nearest town is Sanderson, and after 7pm there are very few, if any businesses open. At the observing site you will need to keep these things in mind:

  • There are no restroom facilities! There are plenty of bushes and trees, and we do make use of them, but if you need to use the restroom you will be getting “up close and personal” with nature. If you have a portable chemical toilet, it might be nice to bring it along for your own use.
  • There is no electricity! If any of your telescope equipment requires power, you will need to bring it.
  • There is plenty of wildlife! It is a forest, so expect to see some wild things. We have seen deer, alligators, snakes, and the strangest assortment of bugs in Northeast Florida. We have never had an incident where anyone was harmed by an animal, but we always observe a healthy respect for the natives.
  • The terrain at the site can vary quite a bit. During the course of a year we will experience mud, high grass, and deep holes. The first few members out usually identify any problem areas, but please be very careful when parking, and even more so when walking. Do not let children run around the observing area.
  • During the summer, bugs are extremely bad in the early evenings! Bring plenty of bug spray. The site is located next to a dip pond, which is often a big breeding ground for mosquitoes.
  • The final mile or so leading to the site is a dirt road. The Forestry Service does re-grade the road about once a year, but it can be rough at times, especially after a rainy period. If you have a particular fondness for your car, please drive carefully and slowly.

Observing Conditions

NEFAS members use the Clear Sky Clock to determine what observing conditions will be at the site. The Clear Sky Clock is usually very accurate and provides a visual representation of sky conditions. The condensed view of the clock is displayed below, or you can click here and view the full version of the clock.

Finding Out if Observing is Still On

Observing sessions may be held on Friday and/or Saturday nights on weekends near the third quarter and new moons and weekends near first quarter if the moon sets early enough. Weather conditions change quickly and can affect our dark sky observing sessions. The best way to find out the status of the session is to check the NEFAS Facebook page. A notice will typically appear the night before or on the day of the observing session. If in doubt just post on the NEFAS Facebook page at least four hours before sunset asking if there will be an observing session that night.

Dark Sky Observing Etiquette

Many of the same rules apply for dark sky observing as for public observing, but because attendees are generally more focused on their observing, we ask that everyone pay closer attention to the following items:

  • Lights: Absolutely no white lights are permitted in the observing area. For reading charts and writing notes, please use a red filtered light only. Please keep dome lights in automobiles turned off. When you leave the observing area, if you cannot turn off your car’s headlights (daytime running lights), please announce to the observers around you that you are leaving and that your lights will be coming on. This is a courtesy especially to any astrophotographers in the area that might be taking long exposures. If you arrive late to the session and cannot turn your car’s headlights off, please park at the side of the road adjacent to the observing area and walk up.
  • Noise: Most people find dark sky observing to be a relaxing experience. Please respect the silence and try not to be too noisy. It’s fine to speak in a normal voice, but please refrain from yelling, and please keep children from doing so as well. It is fine to play music if you like, but keep it low (only loud enough for you to hear it).
  • Pets: If you bring your pet with you to an observing session, please keep him/her on a leash while in the observing area. This is for the courtesy and safety of everyone in attendance. Please do not allow your pets to walk under or around observing equipment or tables. If you would like to let your pet stretch out and get some exercise, there is a large area on the opposite side of the pond where you can let them roam for a while.
  • Young Children: We encourage participation by people of all ages. However, please do not allow young children to run around the observing area unattended. This is for their safety as well as that of other visitors and members. Observing equipment is very expensive, not to mention very easy to trip over in the dark.
  • Observing Equipment: NEFAS members will show you how best to view through a telescope by adjusting focus. Other than that, please keep touching of the scopes and other equipment to a minimum, unless invited to by the owner. Do not grab the scope or pull on the eyepieces.


The meeting place is the Firehouse Subs at I-10 Exit 335 – SR 121 North (South Sixth Street) by the Winn-Dixie. The address is 1448 South Sixth Street, MacClenny, FL 32063

Location of the Sanderson exit and the entrance to the Osceola National Forest:

Dark Sky Map 3

Close-up look at Sanderson and the route leading back to the forest:

Dark Sky Map 4

Map showing the final leg of the drive to the observing site:

Dark Sky Map 5







Sun & Moon

May 16, 2024, 9:31 am
6:30 am
8:16 pm
First Quarter
8 days, 10 hours
2:50 am
2:14 pm

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