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Science Division

Observing Log FAQ

What do you mean in the Observing Log when you ask for...

Altitude (Alt)

Azimuth (Az)

Binary Star

Cardinal Directions

Constellation

Date

Declination (Dec)

Description

Distance

Drawing

Eyepiece

Focal Length

Location

Magnification (Mag. Power)

Mythology

Right Ascension (RA)

Seeing

Spectral Class

Telescope Type

Time

Type

Variable Star

 


Altitude (Alt)

The number of degrees the object is above the horizon. The horizon is at 0 degrees and the point straight overhead (the Zenith) is at 90 degrees.

You should make sure you get this information when you observe the object. Since an object's altitude varies with time, it is not easy to get afterwards.

When your outstretched hand is pointing at the horizon the object's azimuth, you are pointing at 0 degrees altitude. When your outstretched hand is pointing straight up, you are pointing at 90 degrees altitude. Estimate the the number of degrees your outstretched hand is pointing when you are pointing at the object.

You can refer to the Coordinate Systems activity in you course pack for more information.

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Azimuth (Az)

The point where the object is closest to the horizon.

Azimuth is measured in degrees in a circle along the horizon, starting with North.

North is at azimuth 0 degrees.

East is at azimuth 90 degrees.

South is at 180 degrees.

West is at 270 degrees.

Estimate the azimuth of where the object is closest to the horizon.

You should make sure you get this information when you observe the object. Since an object's azimuth varies with time, it is not easy to get afterwards.

You can refer to the Coordinate Systems activity in you course pack for more information.

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Binary Star

A binary star is actually two stars going around each other.

Is the star that you observed actually multiple stars?

You can find this information using Starry Night or an internet search.

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Cardinal Directions

The cardinal directions are: North, East, South and West.

Below your drawing, label the direction you are facing when you are looking at the object.

You should make sure you get this information when you observe the object. Since an object's cardinal direction varies with time, it is not easy to get afterwards.

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Constellation

Which of the 88 constellations is the object in?

Examples are: Virgo, Orion, Sagittarius, etc.

You can find this information on the Star Map that you purchased, or using Starry Night, or an internet search.

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Date

On what date (day/month) did you observe this object?

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Declination

The number of degrees the object observed is north or south of the Celestial Equator.

For stars or constellations, you can find this information on the Star Map that you purchased.

For other objects you could use the Starry Night or use an internet search.

You can refer to the Coordinate Systems activity in you course pack for more information.

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Description

Describe the appearance of the object. This should match your drawing!

Include information about the color, size, and anything else you feel is important.

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Distance

How many light years away is the object?

You can find this information using Starry Night or an internet search.

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Drawing

Your drawing should include as much detail as possible.

Aside from general shape and orientation, you should also include any color that you saw.

Be sure to show any banding, rings, or moons.

Label any moons with their names.

Your drawing should be made while you are observing.

If you have time, go back and look at the object again, after you have drawn it. You will notice more details.

Your drawing should match your description!

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Eyepiece

What was the focal length of the eyepiece in the telescope when you observed the object?

Focal lengths are measured in millimeters, for example: 50mm.

Different focal lengths produce different magnifications.

Since eyepieces are frequently changed, you must note the eyepiece focal length when you are observing an object!

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Focal Length

What was the focal length of the telescope you used to observe the object?

Focal lengths are measured in millimeters, for example: 500mm.

Different focal lengths produce different magnifications.

If you know what type of telescope you used, you can find information about the focal length on our Equipment page.

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Location

Where were you when you observed the object?

This is a general area such as Midland, Boulder Walkway, Traverse City, etc.

Do not include a street address.

Do not be vague, ie: "My backyard".

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Magnification

Magnification is how much bigger a telescope makes an object appear. It is typically a number with the letter 'x' after it to represent how many 'times' bigger the object appears, for example 10x.

This would be spoken as, "Ten times magnification" or "A magnification of ten".

To find the magnification of an observation, divide the telescope focal length by the eyepiece focal length.

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Mythology

Every constellation has a story behind it. Indeed, most constellations have many stories from different cultures and times.

Include a summary of one mythological story for each constellation that you observe. Use the back of the page if you need more space.

You can find this information with an Internet search.

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Right Ascension

Right Ascension is measured in hours along the Celestial Equator. It runs from 0 hours to 24 hours.

For stars or constellations, you can find this information on the Star Map that you purchased.

For other objects you could use the Starry Night or use an internet search.

You can refer to the Coordinate Systems activity in you course pack for more information.

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Seeing

Seeing refers to the steadiness of an image through a telescope or with the naked eye. It depends on atmospheric conditions.

The degrees of seeing are :

Excellent seeing = Very steady image (rare in Michigan)

Good seeing = Fairly steady image

Poor seeing = Unsteady image

No seeing = Cloudy, nothing can be seen!

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Spectral Class

A star's Spectral Class is specified by a letter (O,B,A,F,G,K,M).

You can find this information using Starry Night, or an internet search.

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Telescope Type

What type of telescope did you observe through?

If you are not sure of spelling or specific details, you can see our telescopes on our equipment page.

 

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Time

What time did you observe the object? Make sure to specify am or pm.

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Type

What kind of cluster, galaxy, or nebula did you observe?

You can find this information using Starry Night, or an internet search.

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Variable Star

Is the star always the same brightness or does it change?

You can find this information using Starry Night, or an internet search.

 

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