Keeping a log book

Every observation you make should be recorded in your log book. For this course you should also keep complete records on nights when you are assisting. They will come in handy later. Reserve a few pages at the beginning or end of the book for standard information that you will want to refer to throughout the year. You should also record the steps of each observatory procedure you learn so you can refer to them later.

Your log book should be a hardcover, permanently bound book with either all blank pages or alternating blank and lined pages. The standard science log books are fine.
Notes should be made in pencil or ink.
Sketches should be made in soft pencil.
Comments and corrections made after the observation night should be made in a different colour of ink.

What to include in a log book entry:

Use a new page or draw a line for each new night.
Write down:

Date, time and relevant conditions.
Object/purpose of observation.
Equipment used.
Technique/method used.
Observational notes and sketches.
Where appropriate, the reduction and analysis of data collected, including error estimates.
Discussion and Conclusions.
Later, in another colour: follow-up on subsequent research, corrections or new understanding related to this observation.
When in doubt put down more than less.

Typical log book info:

For each night:

Date, time, location, weather, sky conditions, pertinent sun/moon rise/set times, equipment used, aurora/meteors/etc seen along with anything else you thing might affect the observation.

For each observation:

Purpose
Equipment
Technique/steps/procedure
Observational notes

name(s) of object being observed
coordinates & corrections (show all calculations)
descriptive notes

Sketches

object name
field-of-view circle & size
N, E orientation marks
field stars
descriptive notes

CCD Images

Time taken, exposure, file id and file location
descriptive notes

Any problems you encountered and their solution (if you found one).

Time and sky conditions on closing up. Note any unusual equipment behaviour.

These notes should be made on-site, in "real" time. That means you will have to take two or three minutes every now and then to record. If your writing is messy or disorganized then the night's work should be re-written in a clear and orderly way as soon as possible - the two versions should be together, one after another in the log book so you can always refer back to the original notes. Never erase original notes. Use a different colour of ink for the two versions.

After some time and consideration:

Where appropriate, reduce, analyze and determine error bars for each quantitative observation. Write down critical review of each observation and your conclusions , again in the different colour of ink.

Example logbook entry

When collecting CCD images

In addition to the above be sure to include the following in the appropriate sections of the night's log book entry.

Identity and location (RA, Dec, epoch) of
- visual check star
- guide star
- target
- sky flat fields
Camera operating temperature (e.g. -50 C)
Guide camera position and offset (e.g. west 6.6 cm)
Position of telescope access ports (opened/closed)
Note the location elsewhere in your log book of
- standard equipment used at GAO
- standard opening and closing procedures
- standard guiding procedures
- standard method of collecting calibration images
Condition of the telescope and dome (frost, etc)
Location of the guide star on the guide camera image and typical counts
Reason for the offset location of the target on images, if not centred
Assessment of first collected image: typical sky and max counts, FWHM, etc.
Periodically repeat the above as the data collection continues
List of files saved, not saved (with reasons), start/stop time of each series of exposures
Record of guiding quality: start/stop and typical numeric values, frequency of adjustment, problems, etc.
Assessment of calibration images as they are collected
In general, record any information that is not exactly the same from night to night. If it is exactly the same then it should be in one of the standard sections of your log book.
Follow-up should include the assessment of the calibrated images and a discussion of how the original data could have been improved.

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Last modified: April 27, 2004