Astronomical Observations

Yep you looking up at night through a telescope are continuing on in the world’s oldest science and 1st science- Astronomy.  Ancient Babylonians notice the stars motions from around 1,800 BC on.  Very little was recorded until the invention of cuneiform writing.  Taking a reed and pressing it into a clay tablet.  Very little survived, but in the British Museum they have the above tablet with a record of Halley’s Comet!  In 164 BC the ancient Astronomers in Babylonia recorded on the above tablet in cuneiform the following, “The comet which previously had been in the east,“ reported the scribe in 164 B.C., “became visible and passed along the path of Ea“ in the west.  The apparition of 87 BC was recorded in Babylonian tablets which state that the comet was seen “day beyond day” for a month.

Without writing we would not know about these events.  Now I’m not saying your observations will be studied over 2,000 years from now, but you never know!

Another ancient astronomer- Hipparchus born 190BC is considered perhaps as the greatest ancient astronomical observer and, by some, the greatest overall astronomer of antiquity. He was the first whose quantitative and accurate models for the motion of the Sun and Moon survive. For this he certainly made use of the observations and perhaps the mathematical techniques accumulated over centuries by the Babylonians and other people from Mesopotamia. He developed trigonometry and constructed trigonometric tables, and he solved several problems of spherical trigonometry. With his solar and lunar theories and his trigonometry, he may have been the first to develop a reliable method to predict solar eclipses. His other reputed achievements include the discovery and measurement of Earth’s precession, the compilation of the first comprehensive star catalog of the western world, and possibly the invention of the astrolabe, also of the armillary sphere, which he used during the creation of much of the star catalogue.  But out of the 14 books he wrote on his observations none survived except for one on poetry.

So writing down your observations are important, as well as where you keep them so they will survive for future astronomers to review.

Let’s take a look at the “Father of Observational Astronomy” Galileo Galilei.  In Venice around 1600 glass/lens making started to become much more refined.  At first a simple “Positive Lens” Convex was used to help scholars see as they aged.  Concave lenses could help younger people with Myopia as well.  So these early lens builders could construct lenses for single concepts.  Because they were craftsmen, very little data survives regarding the science behind the construction.  Convex lenses could focus light and a concave lens could redirect the light into parallel rays.  It was stacking these lenses that could magnify distant objects and brought the attention of Galileo to the “Telescope”.


In the Sidereal Messenger we can see what kind of records that Galileo made while viewing in his telescope.

Take a look at some of his observations:

Notice he made tables, sketched what he saw and even kept a record of the weather!  Good things to remember for our own observations.

How about a modern observer?  Let’s look at David Levy’s observational logs.  The RASC did a fantastic job recording these here and gives you a good insight into what a log can look like let alone offer years later.

So, how did this article start?  With me observing the Pleiades last night.  I could see 2-3 stars in the constellation directly and a big white cloud if using my “Averted” Vision.  First time I got to try that!  Look away and then glance towards your nose towards the object and you can see lot’s more!  Way cool.

So what is a good astronomical observation?

Recording anything you see and data to “re-live” the observation.  Finally, you need to do so in a log that will survive.  I’m partial to the written record vice digital, but either is fine.  If you do go the paper route- choose good Archival type paper.

Now there are numerous types of log templates and books out there.  My favorite is Jeremy Perez’s templates at Belts of Venus.  He is a fantastic sketcher/photographer.  Another good site is Astronomy Logs.  The RASC, Astronomical League and many other clubs can and do offer logs for us to record our nights under the stars on.

Bottom line, make a recording for you and others to enjoy.  Put your own flair on it.  It can be as simple as the ancient Babylonia’s did or as complex as you want.  Believe it or not you are a scientist laboring in the oldest science known to mankind, Astronomy.  Take pride in your work and recordings and future Astronomers will enjoy and advance our work.

Well, that’s all for now-












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