Dark Trip Guide in New England

Choosing a Location Dark Skies Finding dark night skies is likely going to be your first criteria when choosing a location for a trip. Living in Cambridge, we are unfortunately surrounded by intense light pollution, making it difficult to see all but the brightest stars and planets. Therefore, for a dark sky trip you have to find a place that has less light pollution, which will allow you to see more objects in the night sky. There are plenty of free online maps, such as https://www.lightpollutionmap.info, that allow you to see where light pollution is lower, and click on a location for more technical details on light pollution. The simplest metric is called the Bortle scale, which qualifies light pollution by classes 1-9. Harvard straddles classes 8 and 9, so just about anything is better. However, to make a trip worth it we would recommend trying to get to at least Class 4 skies. Light pollution can be confusing to figure out, so we have a few FAQs below:

Light Pollution FAQs

● What is light pollution?

○ All the light from streetlights, buildings, cars, and other sources in an urban area is reflected up into the sky. Although any one source of light isn’t that bright, taken together all this diffuse light being thrown up into the sky drowns out relatively faint objects in the sky. As more and more light pollution fills the sky, we lose the ability to see more and more faint stars and celestial objects, until we can see only the brightest.

● What is the Bortle scale?

○ The Bortle scale is a way of rating the amount of light pollution in a location. It divides the amount of light pollution into nine classes, with 1 being perfectly dark skies. The Bortle class doesn’t just tell you how much light pollution there is: it also tells you what you can expect to be able to see with that amount of light pollution. We generally tend to consider locations using the Bortle Scale, since it provides a useful broad and interpretable metric that can help predict what will be visible at a location! For more information on the Bortle scale see here: https://en.wikipedia.org/wiki/Bortle_scale

● How dark do I need to get to see the Milky Way?

○ It depends on what kind of experience you’re looking for! Our galaxy becomes visible in skies darker than Bortle 4

Other Considerations There are several other criteria worth considering when planning a dark sky trip. First is access to the site. Many parks will close after dusk, and may discourage nighttime access, but might be okay with you visiting later at night if you phone ahead. Another important thing to consider is sightlines. Dark skies will be relatively useless if there are trees or buildings blocking all but the view directly overhead. Areas with wide open fields, bodies of water, or points of higher elevation are all good ideas! Weather is also a huge factor. If there are tons of clouds blocking the sky, you won’t be able to see much! The National Weather Service https://www.weather.gov/ is our preferred forecaster, which is generally the most accurate. Weather forecasts will always get more accurate the closer to the actual time, so keep checking up until it’s time for your trip. It’s not location-specific, but the phase of the moon can have a HUGE impact on the quality of your dark sky experience. The moon can throw just as much light into the sky as a city. Regardless of where you go, you won’t see much with a full moon in the sky. A new moon is ideal; a waxing crescent will set soon after nightfall, giving you plenty of time to stargaze afterwards; a waning half-moon or crescent won’t rise until after you’ve started driving back home or turned in for the night. Check in advance! Our Favorite Spots This is a list of spots I made Dark Sky Trips to before, or that board members personal experience visiting and are all good options! The list is in order of closest-furthest Harvard (which also happens to match worst-best skies). All are doable as one night trips, getting back late the same night you left, except for Baxter State Park which is far enough that it needs to be a trip with an overnight stay.

Halibut Point State Park, Rockport MA

● Drive Time: ~1 hour + depending on traffic

● Bortle Class 4

● Access: free, the park technically closes at sunset, but we’ve been told by park authorities that we’re allowed to stargaze from the parking lot at the entrance after dark.

● The closest and easiest place that we’ve found with decently dark skies! The Milky Way will likely be faintly visible, and most major constellations will be findable. Marconi Beach, Cape Cod National Seashore

● Drive Time: ~2 hours depending on traffic

● Bortle Class 3

● Access: free during the off season (most of both semesters), Cape Cod National Seashore remains officially open until midnight, and if you call ahead will likely say that you’re allowed to stay later.

● The place where our last few dark sky trips have gone! Although Bortle class 3 vs 4 may not seem like a huge difference, the skies are significantly darker here than at Halibut Point. In fact, these are the darkest skies within a 2-3 hour drive of Boston that are easily reachable in one night. The Milky Way will be obvious, and naked eye objects like the Pleiades and the Andromeda Galaxy will be noticeably more visible than at Halibut Point. Other beaches on the Cape are good but this is the darkest one that is part of the National Seashore, located between towns. The beach provides wide open sightlines which is great, and if you call ahead and show up by 4pm, you can get a campfire permit and have a fire to help stay warm! https://www.nps.gov/caco/planyourvisit/permitsandreservations.htm

Baxter State Park/North Maine Woods

● Drive Time: ~6 hours

● Bortle Class 1

● Access: Baxter State Park itself closes gates overnight. You must have a camping reservation to be in the park overnight. Adjacent Katahdin Woods and Waters National Monument has 24 hour access. Neither are accessible over the winter. However, some surrounding public roads and logging roads tend to be open year round, and if you can find a good viewpoint on those roads it will be nearly as good!

● This site is by far the most logistically complicated, but totally worth it! These are the only true perfectly dark skies anywhere east of the Mississippi river, with zero light pollution. The Milky Way will have spectacular definition and detail, and it may be hard to find constellations because of the number of stars visible. It would require an overnight stay and potentially a two day car rental making it noticeably more expensive. If anyone wants to try this one, feel free to reach out to Elijah McGill, our Dark Sky Trip Tsar and a Northern Maine local!