Organizing and Running a Public Star Party


There are two basic types of public star party:

The big difference between the two types of event is how you reach your audience. At the "sidewalk" events, you find your guests; at the "dark sky" events, your guests find you. Both are important ways to reach the public.

One format that works well is to pair a formal presentation at sunset, either indoors or outdoors, then follow up with telescopes outside. While the presenter delivers their talk, the other astronomers set up outside. As part of the talk, the presenter can take the opportunity to explain star party safety, talk about how the telescopes work and hand out fliers and star maps. You can also promote your own organization.

Dates around First Quarter Moon are great times to have a city star party, because the Moon is well situated in early evening and has exciting features near the terminator. Dates immediately after New Moon are the best for dark sky events, since you can show the crescent Moon right after sunset and then move on to dark-sky objects soon after it sets.

Try to avoid spaces that are near roads or other sources of frequent headlights. Of course, if you're in the middle of the city, you may have to take what you can get. But above all, you want to be near people. Choose a site within the city that has lots of people already milling about. For a dark-sky star party, choose a site away from bright lights that is still easy for the public to find.

Aside from public accessibility and distance from sky glow, here are some additional factors you should consider for selecting a site:

If your event is scheduled at a dark site away from the city, for example at a state park or an observatory, you will need to publicize it in advance and provide clear directions to find the site. In the city, you can do sidewalk astronomy at any time – just choose a busy street corner, set up scopes, and surprise everyone.

Often, it's good to schedule an event to coincide with a celestial event such as an eclipse. It's easier to get local newspapers to give you free publicity in an article about the celestial event.

Crowd Control and Safety

Take the total number people you expect to attend your event, and divide by 10. The result is the number of telescopes you should expect to have on hand for the evening. That will make sure everyone gets a look without too much crowding or lines at the telescopes. Long lines cause guests to lose interest and create a safety hazard.

Every telescope should be staffed by at least one person. When doing public astronomy, you quite often field questions and interact with the public. It is next to impossible to keep attention on two telescopes as well as your guests – at least I can't!

Use glow-tags, name tags, vests or other means so that people can clearly identify the officials at the observing site.

A bullhorn is a handy item to have on hand, to address the crowd.

Traffic cones are useful for guiding traffic and delineating parking spaces.

Set aside parking for the officials and volunteers with telescopes, so they may all park in one place with easy access, close to telescopes, and separate from public parking. Also, volunteers may leave early if necessary.

Never leave your scope unattended, especially if there are kids nearby. Curious, unsupervised children can fiddle with your equipment, break things, and hurt themselves. One time I turned my back, and a youngster chucked a soda can down the tube of my 10-inch Dobsonian! There is also the obvious possibility of theft.

Do not set up your equipment on uneven ground. Always set up on the sidewalk, a parking lot, or some other flat, smooth area without rocks or other obstacles, to avoid anyone stumbling.

Make sure each telescope is positioned far enough apart to allow the crowd to easily move from scope to scope, without crowding. Crowding increases the chance someone will bump into a scope, or trip over a tripod and get hurt.

If you plan to offer solar viewing with your nighttime scope and a solar filter, remove the finderscope from your telescope, or make sure both objective and eyepiece ends are securely covered. You absolutely do not want people to look through a finderscope in the daytime, and permanently damage their eyesight. Also, if your solar filter is the type that fits over the telescope objective, consider using some tape or other means of binding to be certain the filter cannot slip off, or blow off in a breeze.

Be sure to tell your guests ahead of time that white lights, especially camera flashes, are not allowed on the observing field for the safety and comfort of everyone. You can buy a supply of cheap white flashlights, and color the lens red on each to lend to the crowd. You can find rolls of transparent red tape, used to patch broken taillights, at auto supply stores. If your guests bring their own white flashlights, you can offer them some red tape, or a red balloon to put over the head of the flashlight. The guest then has a red light that can then be used to help them find their way to and from a parking area more safely.

Consider marking important walkways at the observing site, such as the trail to the restroom, using dim red lights or glow sticks so people can easily find their way.

Put some glow-in-the-dark tape or other visible marker on the legs and steps of stepladders, and on your telescope mounts. You can purchase small red LED blinkers that will mark the legs of your telescope tripod and other equipment. Make certain people are not likely to trip or bump over your equipment in the dark.

Try to put away as many accessories, boxes and cases as you can. If you have a car nearby, store them there. If you have to keep extra equipment or cases nearby, move them well outside the line of traffic and consider marking them with a red light or other visible but not blinding marker. You do not want your guests to trip over a box and hurt themselves.

Make sure you have step stools or small ladders so that short people, the elderly, and small children can reach the eyepiece of each telescope. This is especially important for big Dobsonians. Make certain whatever you choose has handles or rails that people can conveniently grab, hold on to, and lean upon. One piece of equipment that may work for you is a folding walker! It it easy to store when not in use. When you put it in the right place, people know just where to stand to view and they have something sturdy to lean on. It only lacks steps to allow people to reach a high eyepiece.

If you use a ladder or step stool, check that the weight ratings of the ladders are clearly posted and visible. Many ladders are rated at only 200-225 lbs. In today's world, even some sixth graders are topping that limit.

Do not use the following items as means of support for your guests:

As guests approach your telescope, tell them in advance (politely) not to touch the telescope. Many people mistakenly believe they can use the telescope as a means of support, and lean against it. Kids especially like to lean on the scope and grab the eyepiece. Large Dobsonians look sturdy and substantial to those unfamiliar with telescopes. People can seriously endanger themselves if they lean against the scope and the tube moves aside (as it was designed to do). Have people lean on a sturdy ladder for support if they have to climb or move in any unnatural way to reach the eyepiece.

When children are helped up onto ladders or step stools, they should always be accompanied by the parent and supervised while on the ladder or step stool. Politely remind a parent to do that if needed. You should never touch a child for any reason in the dark unless it is to save their life. This is good advice to protect those that work at outreach events with children.

There should always be at least two adults from your organization working with any number of kids.This is for multiple reasons including first aid, safety, and liability. If a children's event is scheduled at a location owned by another organization, such as a school, at least one adult from the host organization should be present in addition to two adults from your own organization. Again, this is important for safety and liability.

Keep an eye on youngsters to make sure they do not run around, climb on things, or horse around in general. Often, parents do not carefully supervise their children, and so you may have to remind them to keep an eye on their children for everyone's safety.

For anyone using 110VAC extension cords: A modern UL-approved GFCI (ground fault circuit interrupter) should be used on any extension cords and it should be located as close to the source of the electricity as possible. Tape over cables with duct tape or gaffer's tape to avoid tripping, or cover the cables with a large carpet or rug.

If you have guests whom you suspect are drunk or under the influence of drugs, you should treat them like other guests unless they threaten the safety of others. But do not allow them to climb ladders to look through any telescopes. Instead, direct them to a telescope that they can view while standing on solid ground.

If some guests are causing a serious problem by threatening or endangering other guests, first ask them to stop. Then seek law enforcement assistance such as police, park rangers, etc. Having a phone nearby is useful for this contingency. Don't try to be a vigilante; you can further endanger yourself and others.

Make sure to have multiple club members re-certify in First Aid and CPR for adults and children every year. Also purchase a deluxe first aid kit (not the kind with just band-aids and gauze) for yourself or for your club to have on standby. One club even purchased a defibrillator that goes with them to all outreach events and their remote dark-sky site, and certified club members in its use. Minutes really count when a heart is stopped and fifteen minutes of response time is just too long.

In case of an emergency:


Just about any telescope you have will work well for public astronomy. If your telescope can track objects in the sky, that can be a plus, since you will not need to readjust the scope between viewers to track objects. This does not bother me, but it definitely is an inconvenience for some people. Also, a smaller scope, or one with an eyepiece close to the ground, is good for youngsters who are often too short to look through a larger scope without help.

For the public, ease-of-use usually trumps fine optics. Choose an eyepiece with magnification that frames the subject well, and that has lots of eye relief. This makes it easier for people to acquire a view through the eyepiece. I tend to use longer focal length Plossl eyepieces, along with a Barlow lens to increase the magnification when needed.

You can use fancy eyepieces, but keep in mind you will be cleaning them afterwards – they accumulate a good amount of grime from eyelashes, makeup, etc deposited by your guests. You might consider devoting a set of inexpensive Plossls, plus a Barlow, for public astronomy. This saves your “good” eyepieces from wear and tear due to excessive cleaning.

You may want to provide additional light baffling in your scope in a city environment, to keep out stray light from headlights and streetlights.

People often mistake finderscopes for the actual eyepiece, and try to look through the finder instead. If the finderscope isn't important for balance, remove it and use either a telrad/red-dot finder or the GOTO feature of your scope to locate objects.

Guests with eyeglasses often ask if they should take their glasses off before looking through the eyepiece. You can advise them to try looking through the scope with their glasses on, and only take them off if they can't get close enough to see the view. Eyepieces with good eye relief often allow eyeglass wearers to acquire a view directly with their glasses still on. If they have to take their glasses off, the guest will need to refocus the scope for their uncorrected vision. On most scopes, the focuser is easy to use, but on others it is not. For instance, my homebuilt Dobsonian has a helical focuser which requires two hands to operate properly and is difficult to teach others to use. Regardless, avoid having guests adjust the focus, since it takes time.

A popular trend at public star parties is to attach a video camera to the scope, then televise the view on a video or computer screen for the guests. This method has several advantages. It can allow several people to view at once. It allows the astronomer to easily point out easy-to-miss details or other points of interest. And it allows people with disabilities to easily get a telescopic view. Video cameras optimized for nighttime astronomy are available; online astronomy websites often stock them.

What to Show

If you have several folks with scopes, try to decide in advance amongst yourselves what objects you'll be showing. That way, everyone won't all point at the Andromeda Galaxy or M13. People can then go from scope to scope and sample lots of different celestial objects.

To help organize folks before the event, you could make a list and print finder charts for each object using planetarium software. Then let all the scope owners grab maps for their favorite objects. Having the maps makes it easier for them to “buy in” to the idea, and the star charts make assigning objects simple.

If I can't get advance agreement beforehand, I usually choose a less common object. For example, instead of M13 I'll choose M22 or M92. Instead of the M57 Ring Nebula I'll choose the Swan Nebula. That increases the odds guests will see something unique as they move from scope to scope.

I tend to stick with the same object for a while, before moving to the next one. Less time is spent aiming the scope, and more people get to view. Plus, people waiting in line feel “cheated” if you aim the scope somewhere else before they have had a chance to look. Sometimes you will have a short period with no one waiting in line. That's the best time to change targets.

People love the Moon. Their first view of lunar craters close up is often overwhelming. If you can, schedule your star party on a night the Moon will be available. Also be sure to point out any naked eye planets such as Venus or Mercury that can be seen in the early evenings.

A volunteer can point out the constellations and tell constellation stories for those who are interested. Most people have no idea where the constellations are so are fascinated. Green laser pointers are ideally suited for this kind of activity.

Engaging the Public

People will ask questions. Make sure you have prepared some simple facts in advance about the item you're showing that you can share, and maybe a little story about the science behind it. Explain to guests looking in your telescope where they are looking in the sky and give them a bit of information about the object they are viewing. This adds more meaning to their experience.

If you don't have your own telescope set up, you could be a sort of floating “guide” for the guests. You can walk around answering questions or helping as needed. Inevitably, there is someone who is very interested and wants to know more than there is time to tell them at the eyepiece, or has questions that take more time than is available with others waiting in line.

Prepare some handouts and fliers you can give away to promote astronomy or your organization. You can see one we've prepared at the SF Sidewalk Astronomers.

Another thing you can do is to print business cards with the name of your organization, and contact info such as email or website address. There are places online which will print business cards for free or nearly free, with an ad for the printing company on the reverse. The cards make it easy for visitors to find you in the future, and perhaps join your organization.

You could set up a table or small booth stationed with two people to provide handouts, brochures and other items to the public. Set it up at a conspicuous area of your observing site.

Some people will be ecstatic over a telescopic view, others will be disappointed because they can't see a Hubble photo through your eyepiece. Be prepared to explain a little bit about how the human eye differs from cameras, and how amateur telescopes don't gather as much light as huge observatory cameras with hours-long exposures. But you can emphasize the immediateness and directness of the experience, which no photograph can ever convey.

Lots of people will ask questions about your equipment, especially if the scope is home-made. I answer those questions, but I don't dwell upon equipment for too long. Sometimes that's all people want to talk about, and that can be a distraction from sharing information about what's in the eyepiece. Don't set up too much equipment, which only invites more questions about the equipment and less about the view. Keep it simple.

Always emphasize to astronomers that are new to helping with star parties that the people who come are guests and thus need to be treated as such at all times. No matter how well we prepare we find that there is often something new that comes up that we never thought about. To that end it is useful to be flexible and ready to seize on new opportunities to connect with the guests!

Handling Difficult Questions

If people ask how much your equipment costs, you can deflect the question by coyly answering, “Well, the scope really is not for sale.” Some people who are interested in astronomy could be scared away by the pricetags associated with high-end equipment, and the amounts of money hardcore enthusiasts often spend on the hobby.

If you are pressed on the issue of price, simply point out how cheaply one can get started in the hobby – a $75 pair of binoculars and a magazine subscription – and how you can graduate to more advanced equipment as your interest in the hobby develops.

Keep a small list onhand of introductory books or websites that you can refer people to. Often people who look through a scope are very interested in astronomy, but have no idea where to start. You typically don't have time at a star party to answer them in depth the way they would like, but you can give them references for further reading. Sometimes this can also help defuse a “difficult” guest.

If you get kooks asking questions about UFO's, astrology, and other bunk, you can give them a short dismissal of the topic. You can find some pre-made answers to these sorts of questions on the San Francisco Sidewalk Astronomer's website.

You can also check out for lots more information to prepare yourself.

If a guest persists in asking pseudo-science questions or regaling you with their UFO conspiracy theory, simply tell them (politely) that's not what you're here for and that they're keeping you from seeing the other people in attendance. Then ignore them.


Thanks to the members of the Astronomical Association of Northern California (AANC), and especially the Mount Diablo Astronomical Society for reviewing this document, offering corrections, and suggestions for additional content. Special thanks to members of the Yahoo! AstronomyOutreach group, especially Neta Apple, Patty Mayer, and Lonnie Puterbaugh for their suggestions and additions to this guide.