1.4 Introduction: Best Practice
5
Prepare properly for a night’s observing. Before you set off, you need to think
about what you’re planning to do and how you will go about achieving it. First of all,
if your observation is part of a course, then make sure that you’ve read the practical
notes and that you understand them. You should have a list of the observational
targets that you want to work on and their coordinates in the sky. You should also
know what exposure times and filters you need. You should also note the position
of the Moon in the sky. This can become important, especially if it’s at or near full
phase.
If it’s possible to find out in advance, it’s a good idea to know what instrument
and camera you will be working with. Not all cameras and instruments are equal,
and some specific setups may have implications for your work. It’s also a good idea
to have a list of backup objects in case your primary targets are obscured. Never
assume that there won’t be a single solitary cloud parked in the worst possible bit of
the sky. Telescope time is expensive, and the weather is not dependable.
It’s also important to have some means to get your images off the camera control
computer, such as memory sticks and cloud services. Different observatories have
different standard methods, so check with the staff.
If you do as much preparation as you can in advance, you will have a rewarding
and reasonably stress-free observing session.
The most important tool you will have with you whilst observing is your lab book.
You need to record everything that happens during the course of your observations.
Include the telescope name and its optical characteristics (we’ll return to these details
later on). Here is a list of the things you need to record:
• the time and date of each observation;
• the instrument you’re using on the telescope;
• the exposure time for each observation;
• the filter used for each observation;
• the ID of the target that’s being observed;
• its location on the sky.
In addition, you should record the weather conditions, the sky brightness (if
known), and the seeing (i.e., the quality of telescopic observation). We’ll show you
how to work this out later on. These details are essential if you later wish to make
a quantitative assessment of your data quality. If you are observing as part of a
group, don’t assume that someone else is taking all the notes. They probably are not.
Always make your own notes and make them as thorough and detailed as possible.
Keep in mind that precision is a key aspect of experimental science. If at all possible,
always record the uncertainties on the data that you’re taking. You should ask yourself the question, “Could another scientist reproduce my methods based on what I
have written down?” The answer should always be yes.
Given the nocturnal nature of astronomy, it can be extremely cold when you are
observing, so ensure that you dress appropriately for the weather, including footwear.
It is easy to remove a jacket if you are too warm, but you cannot put one on that you
have not brought. Telescope domes are unheated, so unless you are lucky enough to
have a control room, you are as likely as not going to be exposed to the elements.
5
Prepare properly for a night’s observing. Before you set off, you need to think
about what you’re planning to do and how you will go about achieving it. First of all,
if your observation is part of a course, then make sure that you’ve read the practical
notes and that you understand them. You should have a list of the observational
targets that you want to work on and their coordinates in the sky. You should also
know what exposure times and filters you need. You should also note the position
of the Moon in the sky. This can become important, especially if it’s at or near full
phase.
If it’s possible to find out in advance, it’s a good idea to know what instrument
and camera you will be working with. Not all cameras and instruments are equal,
and some specific setups may have implications for your work. It’s also a good idea
to have a list of backup objects in case your primary targets are obscured. Never
assume that there won’t be a single solitary cloud parked in the worst possible bit of
the sky. Telescope time is expensive, and the weather is not dependable.
It’s also important to have some means to get your images off the camera control
computer, such as memory sticks and cloud services. Different observatories have
different standard methods, so check with the staff.
If you do as much preparation as you can in advance, you will have a rewarding
and reasonably stress-free observing session.
The most important tool you will have with you whilst observing is your lab book.
You need to record everything that happens during the course of your observations.
Include the telescope name and its optical characteristics (we’ll return to these details
later on). Here is a list of the things you need to record:
• the time and date of each observation;
• the instrument you’re using on the telescope;
• the exposure time for each observation;
• the filter used for each observation;
• the ID of the target that’s being observed;
• its location on the sky.
In addition, you should record the weather conditions, the sky brightness (if
known), and the seeing (i.e., the quality of telescopic observation). We’ll show you
how to work this out later on. These details are essential if you later wish to make
a quantitative assessment of your data quality. If you are observing as part of a
group, don’t assume that someone else is taking all the notes. They probably are not.
Always make your own notes and make them as thorough and detailed as possible.
Keep in mind that precision is a key aspect of experimental science. If at all possible,
always record the uncertainties on the data that you’re taking. You should ask yourself the question, “Could another scientist reproduce my methods based on what I
have written down?” The answer should always be yes.
Given the nocturnal nature of astronomy, it can be extremely cold when you are
observing, so ensure that you dress appropriately for the weather, including footwear.
It is easy to remove a jacket if you are too warm, but you cannot put one on that you
have not brought. Telescope domes are unheated, so unless you are lucky enough to
have a control room, you are as likely as not going to be exposed to the elements.