How to Observe
Observing is one of the biggest thrills — and one of the biggest challenges — in astronomy. This article presents advice for the new observer based on what I've learned over the course of almost 800 hours of observing. Although my expertise is in radio observing, I've tried to make the advice general enough to be useful for any observer.
Observatories are dangerous places with plenty of hazards like heavy machinery, wild animals, poisonous insects, fires, and mountain roads. Your safety, the safety of your fellow observers, and the safety of the telescope should be your most important considerations when observing.
Be aware of the hazards at your observing site. Some observatories require observers to complete safety briefings informing them of the hazards on the site. If the observatory you're visiting doesn't, inquire with the locals about potential hazards before heading to the telescope or early on in your run.
You will be tired during an observing run and that will lead to stupid mistakes. No one operates well with little or no sleep. Make sure that your fatigue does not compromise your safety or the safety of others. Get plenty of sleep before doing anything potentially dangerous like navigating winding mountain roads or handling liquid nitrogen. Many observatories provide a shuttle service to the observatory, so you don't have to drive up and down the mountain while tired.
If your budget permits, bring an observing buddy: two brains are better than one when tired. Having two people monitoring the observing and calibrating the data reduces the chance for error. You can also switch off observing if one person gets too tired.
Advance preparation is the key to a successful observing run. Read the telescope documentation thoroughly. Ideally, this documentation should tell you:
- How to get to the telescope
- What sort of food and accommodations are available at the telescope
- How you operate the telescope
- What are the common observing strategies
- What calibration data you need
If you have any questions, contact observatory staff and other experienced observers. If the telescope documentation is outdated or non-existent, check with observatory staff or other people who have observed with that telescope to get the necessary information.
Know how you want the equipment configured and double-check that the right instrumentation will be on the telescope. In the optical and infrared, you typically want to know
- What filters are you going to use?
- How do you want the spectrograph set up?
- What lines are you going to observe?
- What receiver are you going to use?
- What backend are you going to use?
- How do you want the backend set up?
- What lines and/or continuum frequencies are you going to observe?
Have all the relevant information about your sources in an easily accessible place. Do not rely on having internet at the observatory. Observatories are in remote locations, so the internet connections are generally not the most stable. Phones are usually more reliable, but can still go out. Good things to know about your sources include their positions, their rise and set times in LST, UT, and local time, their brightnesses, and if you're doing spectroscopy, their radial velocities. Make sure that you have the values in the coordinate systems that are expected by the telescope. If you're doing optical observing, an application like Jskycalc can provide this information. In the radio, I use the Interactive Observability Chart Plotter from ATNF to get the rise/set times for my sources.
I write up a detailed checklist for the night's observing several hours before my observing starts. The checklist makes starting up easier and helps you make sure that you're getting everything you need to calibrate the data.
Constantly monitor the state of your data and the telescope while observing. Know how to recognize when things are going right and what signals trouble. If anything looks wrong, don't just plow ahead! Spend some time thinking about what might be wrong and if it's going to affect your science. Many observatories have on call support that you can contact during a run if there is something seriously wrong. Report any non-critical problems observing to observatory staff during business hours.
Take Care of Yourself
Pack warm clothing, a flashlight, and some entertainment. Most observatories are located on mountain tops where the temperature can be 10-30F colder than at sea level. Even if it's warm at the telescope, it will still be cold in the control room. I pack layers so that I can easily regulate my temperature. A flashlight is always handy; make sure it's a red flashlight for optical observatories. Sometime during the run you are going to get really sick of observing — it's good to have some mindless TV or novels or video games to help you relax and finish off the run.
Leave plenty of time to get to the observatory. Weather, flight delays, getting lost, etc., can make it more difficult to get to the observatory than anticipated. If you arrive early, you have some time to settle in and consult with the local experts if you have any last minute questions. You also might have the opportunity to watch another team observe — this gives you a chance to see how observing works at that telescope.
Several days before the run, try and adjust your sleep schedule to match your observing schedule. The first night of observing will be much easier if you're already on that schedule. At radio observatories, however, this may be impossible because you can be scheduled any time your sources are up.
Eat well, making sure to get plenty of fruits and vegetables. I always bring some food with me to the observatory either in my luggage or from a grocery store on the way to the observatory. That way if I get hungry at a weird time I have something to eat. Another good thing to bring is the caffeinated beverage of your choice. Caffeine-free observing runs are not recommended.
Get some exercise. Hiking or walking are generally possible at most observatories. Many radio observatories also have bikes. Depending on where you're at, ping-pong or pool tables may also be available.
Calibrate Your Data as Soon as Possible
Observing takes time and money. To get maximum return on your science, plan on calibrating your data as soon as possible. If you are calibrating data during the run, you have the opportunity to catch errors and correct them in future observations. Having an observing buddy makes this easier — one of you can reduce the data, while the other observes. Sometimes full calibration of the data isn't possible at the telescope. However, it's still a good idea to do a detailed examination of the raw data and a rough calibration to make sure everything is working well.
Hints for Remote Observing
Remote observing is quickly become the most common observing method. For the most part, it works like observing in person with some additional minor considerations.
I make sure I have the fastest and most reliable internet connection possible. I also try and have an observing buddy looking at my data as I observe. Having an additional observing buddy in another location also helps if your network connection goes down.
Give the operator your contact information and know how to reach the operator in the event that your network connection goes down. A couple of observatories allow you to send your observing plan to the operator ahead of time. Then if the observatory loses its connection to the outside world, you can still get data.
The above was originally written by Amanda Kepley. Additions from others below.
Tips From Others:
- Most observatories are located in very dry locations. Pack lots of hand lotion, lip balm, and a water bottle.
- Bring — or buy on your way — any particular favorite snacks or beverages. The observatory will have a procedure in place for ordering or preparing a night lunch, but having your favorite candy or tea around at 4:00AM can provide a nice pick-me-up and energy boost. (And on that note, caffeine-free observing runs can work just fine! But you might want to substitute sugar, so be prepared!)
- Bring or borrow a pair of binoculars and GO OUTSIDE periodically during your nights. Check the weather, note where the clouds are (yes, even if there is a fancy cloud camera, it's still good to look at them with your own eyes), and look at the stars! That's why most of us got into astronomy in the first place, because we were fascinated by the night sky. You'll rarely have darker skies than during a run, so set a long set of exposures going and spend some time stargazing.
Inevitably, you will be unable to observe for some reason (clouds, humidity, dust, high winds, drop bears, etc.). One of the most pressing questions for beginning observers is how long should one wait before giving up and going to bed. One rule is: After twilight has ended, wait for one hour per meter of telescope aperture for the weather to improve. So if you have Keck time, you're stuck waiting all night, but only about half the night if you're using a 4m. However, rules on when to close are not universally well established; there are many variations, so make sure you're clear on what your supervisor expects. A variation of the one presented above is that going to bed on a cloudy night goes according to aperture in the following way: 1m telescope=1AM, 2m telescope=2AM, etc. But you don't have to! If there's a chance the clouds will clear, it's perfectly okay to wait for the entire night, especially if you're on a small telescope and are the only one in control. On larger ones, consider the advice of your operator. They know the sites very well!
- In the vein of bad weather, if your main science project requires good seeing, or photometric skies, or some other condition threshold, make sure you have back-up projects planned that can be done in poor seeing conditions, through thin clouds, etc. There are always bright variable stars that need light curves or orbital period measurements. Don't let your telescope time go to waste just because conditions aren't perfect!
- Have some redundancy when it comes to getting your data home. Carry a copy with you on DVDs, an external hard drive, or your computer (if you have enough empty space). Additionally, send a copy of your files back to a machine at your home institution in case your luggage gets stolen, your computer breaks, etc.
- Keep your own notes in either a physical or digital notebook, or both! Many telescopes have computer-generated logs, and of course the FITS headers should have many pertinent details, but having your own log can come in handy during the run (How long did I expose those perfect twilight flats yesterday?) and later on when you are processing the data (Why do these images look terrible? Oh, clouds!).
- It's a good idea to bring some common over-the-counter medicines with you, but if you run out, or don't have any, or need something different, most (all?) observatories have a medic on the mountain who can help you out if you become ill. Don't hesitate to ask!
- The bedrooms in the lodge have ethernet connections, but no wi-fi. The control rooms have both, but the ethernet is faster/more reliable.
- The bedrooms have blow dryers in them, but they are not very powerful. If you have long hair, you might want to bring your own, especially during the colder months when you won't want to be outside with wet hair.
- If you drop off your night lunch order on your way to bed, you don't have to worry about not getting one for the next night because you overslept and missed turning it in at regular lunch.
- It turns out it's not actually normal to find a lot of scorpions in your bedroom. Tell a staff member so they can set up a visit from the exterminator.
- If you are VPN'd into your home institution, you won't be able to access the (old) night report webpage, or the (new) internal environmental page. You can pull them up on another control room computer if you don't want to disconnect the VPN. You will have to disconnect to copy files over to your personal computer/hard drive.
- All of the bedrooms and control rooms have US-style outlets, so you don't technically need a converter/adapter, but it's not a bad idea to bring one just in case.
- CTIO maintains a list of restaurants near the Recinto (the AURA/CTIO/Gemini complex in La Serena) at http://www.ctio.noao.edu/misc/rest.html
- If you are staying overnight at the Recinto, the second key on your room keychain opens the first room at the motel, which is a small kitchen/common area where you can find water bottles, snacks, and ingredients for making a small breakfast. There's also a fridge, stove, and microwave if you want to store and reheat leftovers. Please clean up after yourself!
- If you find yourself with time to kill in the Santiago airport (but not enough time to leave the airport and explore the city), if you buy food or a drink at most (any?) of the restaurants, you can also ask for a wifi code so you can get online.
- The same advice goes for scorpions in the control rooms at Kitt Peak--let a staff member know if you are seeing them so the exterminator can be called.
- It is easiest to submit your night lunch order at the same time you submit your night report.
- There is no wi-fi or cell phone usage at Kitt Peak, because of the radio telescope. Make sure you can connect to the internet via ethernet if you bring your own computer.
- You'll prepare your own night lunch at dinner time. Make sure to label it before putting it in the shared fridge!!!
- The water is very hard — bring extra shampoo.