Sources/First cyan source in Caelum

The first cyan source in Caelum is unknown.

This is an image of NGC 1679 in Caelum. It is a spiral galaxy located two degrees south of Zeta Caeli. Credit: NASA/ESA (Wikisky).{{fairuse}}

This is a lesson in map reading, coordinate matching, and searching. It is also a project in the history of cyan astronomy looking for the first astronomical cyan source discovered in the constellation of Caelum.

Nearly all the background you need to participate and learn by doing you've probably already been introduced to at a secondary level.

Some of the material and information is at the college or university level, and as you progress in finding cyan sources, you'll run into concepts and experimental tests that are an actual search.

To succeed in finding a cyan source in Caelum is the first step. Next, you'll need to determine the time stamp of its discovery and compare it with any that have already been found. Over the history of cyan astronomy a number of sources have been found, many as point sources in the night sky. These points are located on the celestial sphere using coordinate systems. Familiarity with these coordinate systems is not a prerequisite. Here the challenge is geometrical, astrophysical, and historical.

NGC 1679 in the image at left appears to contain some cyan, probably as a result of a mixture of light blue and yellow.

First step


The first step is to succeed in finding a cyan source in Caelum.

Next, you'll need to determine the time stamp of its discovery and compare it with any that have already been discovered.

Over the history of cyan astronomy a number of sources have been found, many as point sources in the night sky. These points are located on the celestial sphere using coordinate systems. Familiarity with these coordinate systems is not a prerequisite. Here the challenge is geometrical, astrophysical, and historical. The coordinates are usually supplied by the cyan source observers.

Control groups


A control group for this experiment may be a cyan source observed by ancient hominins in their version of the constellation Caelum.

Astronomical cyan sources


The electric blue glow of electricity results from the spectral emission of the excited ionized atoms (or excited molecules) of air (mostly oxygen and nitrogen) falling back to unexcited states, which happens to produce an abundance of electric blue light. This is the reason electrical sparks in air, including lightning, appear electric blue. It is a coincidence that the color of Cherenkov radiation and light emitted by ionized air are a very similar blue despite their very different methods of production.

Traveling cyan sources

This is the appearance of the Sun in visual radiation centered in the yellow-green. Credit: Jim E. Brau, Pearson Prentice Hall, Inc.{{fairuse}}

Many cyan sources do not remain in a constellation for lengthy periods. Some of these are the Sun and sources apparently in orbit around the Sun. The Sun travels through the 13 constellations along the ecliptic (the plane of the Earth's orbit around the Sun): the 12 of the Zodiac and the constellation Ophiuchus. These are described in source astronomy. Caelum is not one of the constellations of the Zodiac.

First sources


The "earliest known astronomy anywhere in the world [is] that of the Australian Aborigines, whose culture has existed for some 40,000 years".[1]

"The Aranda tribes of Central Australia, for example, distinguish red stars from white, blue and yellow stars."[1]



To introduce yourself to some aspects of the challenge may I suggest reading the highlighted links mentioned above, and if you're curious, those listed under the section "See also" below.

Cyan rays are a form of radiation that is currently part of the electromagnetic radiation intersecting the Earth. More information about radiation is in radiation astronomy.


This is an image of the International Astronomical Union (IAU) sky map of the constellation Caelum. Credit: IAU and Roger Sinnott & Rick Fienberg, Sky & Telescope magazine.{{free media}}

The Wikipedia article about the constellation Caelum contains a high school level description. The figure at right shows the sky map of Caelum. Around the edges of the map are coordinates related to longitude and latitude, but with the Earth rotating on its axis every 24 hours the celestial coordinates must remain fixed. How has this been accomplished?

Also, in the Wikipedia article is a list of stars in Caelum. What's the difference between a star and an astronomical cyan source?

From the Wikipedia article on the Zodiac, is Caelum a zodiacal constellation?

Caelum is a faint constellation in the southern sky, introduced in the 1750s by Nicolas Louis de Lacaille.

"Caelum is depicted as a sculptor’s chisel. It first appeared in Lacaille’s map of the southern stars published in 1756, as “les Burins,” a pair of crossed burins connected by a ribbon. (Burins are sharp engraving tools.)"[2]

"In Johann Bode’s star atlas Uranographia, the constellation still had the longer name, Caela Scalptoris."[2]

Star classification by color

Class Temperature[3]
Conventional color Apparent color[4][5][6] Mass[3]
(solar masses, Mʘ)
(solar radii, Rʘ)
(bolometric, Lʘ)
Fraction of all
main sequence stars[7]
O ≥ 33,000 K blue blue ≥ 16 ≥ 6.6 ≥ 30,000 Weak ~0.00003%
B 10,000–33,000 K blue to blue white blue white 2.1–16 1.8–6.6 25–30,000 Medium 0.13%
A 7,500–10,000 K white white to blue white 1.4–2.1 1.4–1.8 5–25 Strong 0.6%
F 6,000–7,500 K yellowish white white 1.04–1.4 1.15–1.4 1.5–5 Medium 3%
G 5,200–6,000 K yellow yellowish white 0.8–1.04 0.96–1.15 0.6–1.5 Weak 7.6%
K 3,700–5,200 K orange yellow orange 0.45–0.8 0.7–0.96 0.08–0.6 Very weak 12.1%
M ≤ 3,700 K red orange red ≤ 0.45 ≤ 0.7 ≤ 0.08 Very weak 76.45%.

Testing a source


There are many web sites that may have a cyan source listed for the constellation Caelum.

Wikipedia sources


A. Constellation article

Under "Notable features" in the Wikipedia article on the constellation Caelum is the list of stars in Caelum. Click on this link. In the table of this Wikipedia article is α Cae. To the right are coordinates:

  1. Right ascension (RA): 04h 40m 32.62s and
  2. Declination (Dec): -41° 51' 48.9".

Find these coordinates on the Caelum map at the right. Is alpha Caeli really inside the boundaries of the constellation?

To evaluate the star as a cyan source, skip ahead to the section "Cyan source".

B. Wikipedia search

Another way to look for cyan sources in the constellation is to perform a search on Wikipedia. Try "Caelum cyan" without the quotes. This yields no possible astronomical cyan source candidates. "Caelum blue-green" yields only Eridanus (constellation) where a blue-green star is described. This may be a good candidate for the first cyan source in Eridanus.

To evaluate a cyan source, skip ahead to section "Cyan source".

SIMBAD sources


Another way to find possible cyan sources in Caelum is to use search queries on SIMBAD.

Click on the SIMBAD link under "External links" below, then click on "Criteria query" or "by criteria".

In the tan box, type in "region(04 40 32.62 -41 51 48.9, 10m)", without the quotes. This tells the SIMBAD computer you are interested in a circular region of the celestial sphere centered on the coordinates for alpha Caeli, with a radius of 10 arcminutes (m).

Notice on the page over at the right from the tan colored box: "Return". The default is "object count". Click on "submit query". In a few moments a result something like "Number of objects: 9" should appear. Click "Back" to see the tan box again.

To see if you have found at least one object, change "Return" to "display" by clicking on the circle to its left, then "submit query".

SIMBAD should display a list of objects. Read through the resource cyan astronomy for clues that may indicate whether a particular spectral type (Sp type) is a cyan source. If none of the objects listed seems to be described as a cyan source, try going "Back" and increasing the arcminutes from "10m" to "20m", and repeat until a cyan source is found.

Once you believe you have discovered a cyan source, proceed to the section "Cyan source".

Cyan source


There are several ways to evaluate a cyan source for the constellation Caelum.

Wikipedia source


Click on the link to the Wikipedia article. After you've enjoyed reading about the source, use the 'find' command of your browser to see if this Wikipedia page mentions anything about "cyan", "blue-green", "green-blue", or "cyan rays". Does the article mention whether or not the source is a cyan source?

What is the current time stamp for the Wikipedia article on the source? [Hint]: look for something like "This page was last modified on 12 January 2012 at 06:47." very near the bottom of the page. For now this is an adequate time stamp.

From reading the Wikipedia article on the source, if you believe the text demonstrates that the source is not a cyan source in Caelum edit the "Non-cyan source in Caelum" section near the bottom of the page with an entry similar to "# Alpha Caeli 12 January 2012 at 06:47 Wikipedia article "Alpha Caeli".", without the outer quotes, and finish the entry with four "~"s without the quotes after the period. The date included with your designation or username is a time stamp for the entry. The last portion of the entry is the source of your information.

On the other hand, if there are one or more sentences in the article that you believe demonstrates that the source is a cyan source in Caelum edit the section below "Cyan source in Caelum" with a similar entry.

Go to the section entitle, "Challenging an entry".

SIMBAD source


To check any source (even one from Wikipedia) on SIMBAD, click of the "External link" to the "SIMBAD Astronomical Database".

At the lower right side of the SIMBAD Astronomical Database page is a "Basic search" box. There are several ways to try your target:

  1. source name: without the quotes or
  2. source coordinates: without the quotes, for example, "04 40 32.62 -41 51 48.9".

If you are looking at a SIMBAD generated table which lists possible targets, click on one.

On its SIMBAD page move over to the right side until you see an Aladin visual photograph of the object. Is it a cyan source?

Even if the source does not look cyan, look down the left hand side of the page for "Spectral type:". From your reading of cyan astronomy, do you believe the source is a cyan source, or not? Noting that SIMBAD does, or does not consider the source to be a cyan source is important, so skip down to the "SIMBAD time stamp" section.

If you have already found a cyan source (or a table of them) using SIMBAD, click on the blue link identifier for the first.

SIMBAD time stamp


Peruse the SIMBAD page for a time stamp or date of last revision. [Hint: it may look something like "2012.01.09CET20:10:02" and be in the upper right.]

If the entry at SIMBAD convinces you that the source is not a cyan source, edit the "Non-cyan source in Caelum" section near the bottom of this page and type in an entry similar to "# Source Name 2012.01.09CET20:10:02 SIMBAD article "SIMBAD source name".", without the first set of quotes, followed by four ~s.

If your SIMBAD analysis convinces you that you have found a cyan source in Caelum (did you check the coordinates vs. the map of Caelum?), make an entry something like the ones in the section "Cyan source in Caelum".

Challenging an entry


Any entry in either the section "Cyan source in Caelum" or "Non-cyan source in Caelum" can be challenged. The time stamp may be challenged to see if there is an earlier one. The source may be challenged by an earlier source.

Wikipedia challenge


Is Wikipedia a 'primary source', or does the Wikipedia article cite a source?

Even though Wikipedia has an article on the source, is it a good place to stop in testing whether the source has been detected as an astronomical cyan source?

If the Wikipedia article cites a primary source, skip down to the section on "Primary sources".

SIMBAD challenge


Is SIMBAD a 'primary source'?

SIMBAD is an astronomical database provided by the Centre de Données astronomiques de Strasbourg. It is an authoritative source, but they do occasionally make a mistake.

If you find a cyan source within the constellation on SIMBAD, the next step is to find the earliest time stamp of discovery.

Primary sources


Primary sources may be searched for possible additional information perhaps not yet evaluated by SIMBAD or not presented in a Wikipedia article about a source.

Wikipedia test source


For a Wikipedia article that cites a primary source, scroll down to the reference and open the reference. Read through the article looking for where the source mentioned in the Wikipedia article occurs. Some primary source authors may use source designations that are not mentioned in the Wikipedia article. To look for other designations, click on the link to SIMBAD in the "External links" on this page, enter the source name from the Wikipedia article, and see if other names are mentioned in the article.

When none of the names are mentioned, click on the link for "Google Advanced Search" in the list of "External links", enter the source name or designation(s) such as "Gliese 866", with "cyan" to see if the source has a reference indicating it is a cyan source. And, look for the earliest one. Compose an entry using the primary source.

SIMBAD test source


Further down the SIMBAD page is a list of "Identifiers". Click on the blue bold portion.

On the page that appears, there should be a primary source listed after Ref:. Click on the blue link with the oldest year. This yields an earlier time stamp and entry citation like the current one in the section "Cyan source in Caelum". If you find another source or an earlier time stamp, compose a similar entry and edit the section. Additional information to add into the reference can be found by clicking on "ADS services" from the SIMBAD page.

Changing an entry


From your analysis of the source so far, is it a cyan source?

If you have found an earlier time stamp for the source than the one listed in the section below "Non-cyan source in Caelum" and the answer to the above question is "no", you can edit the section with your result. Or, you can leave the entries as is and try another star or object.

If you have found an earlier time stamp for the source than the one listed in the section below "Cyan source in Caelum", edit the section with your result. Or, if you found another cyan source with a comparable or earlier time stamp, edit the section with your result.

Cyan sources in Caelum

  1. The list of stars in Caelum contains the entry "3 G. Cae" at right ascension (RA) 04h 27m 05.92s declination (Dec) -46° 56' 49.6", spectral type F8V. Inputting the RA and Dec into SIMBAD using "region(04 27 05.92 -46 56 49.6,10m)", clicking on "display", then "submit query" yields a list of objects containing LTT 1989 approximately at the coordinates for "3 G. Cae" but with a visual spectral type of F5.5V. Using 40m, yields HD 28079 an F9V and HD 28155 an F7V. --Marshallsumter (talk) 10:59, 15 August 2012 (UTC)
  2. The list of stars in Caelum contains the entry "27 G. Cae" at RA 05h 03m 53.94s Dec -41° 44' 43.2", F8V. Using a "Query by criteria" on SIMBAD with region(05 03 53.94 -41 44 43.2,10m) yields HR 1651 an F8V. --Marshallsumter (talk) 11:45, 15 August 2012 (UTC)

Non-cyan sources in Caelum

  1. Alpha Caeli A is an F-type main sequence star with a visual stellar classification of F2V. Temperature 6,991 K.[8] Cyan stellar sources are likely between stellar classifications F7V and F9V. --Marshallsumter (talk) 10:40, 15 August 2012 (UTC)
  2. Beta Caeli "is categorized as an F-type main sequence star ... F2V"[9]. --Marshallsumter (talk) 10:40, 15 August 2012 (UTC)
  3. Gamma Caeli, according to SIMBAD, is a K3III. --Marshallsumter (talk) 10:40, 15 August 2012 (UTC)
  4. Delta Caeli, according to SIMBAD, is a B2IV-V. --Marshallsumter (talk) 10:40, 15 August 2012 (UTC)

Oldest records



  1. The first cyan source in Caelum may have been observed some 42,000 b2k.

See also



  1. 1.0 1.1 R Haynes (June 27, 1996). Raymond Haynes. ed. Explorers of the southern sky: a history of Australian astronomy. Cambridge, England, UK: Cambridge University Press. pp. 527. ISBN 0521365759. Retrieved 2013-08-02. 
  2. 2.0 2.1 Constellation-Guide (18 July 2014). Caelum Constellation. Constellation-Guide. Retrieved 2014-07-18. 
  3. 3.0 3.1 3.2 3.3 Tables VII, VIII, Empirical bolometric corrections for the main-sequence, G. M. H. J. Habets and J. R. W. Heinze, Astronomy and Astrophysics Supplement Series 46 (November 1981), pp. 193–237, bibcode=1981A&AS...46..193H. Luminosities are derived from Mbol figures, using Mbol(ʘ)=4.75.
  4. The Guinness book of astronomy facts & feats, Patrick Moore, 1992, 0-900424-76-1
  5. The Colour of Stars. Australia Telescope Outreach and Education. 2004-12-21. Retrieved 2007-09-26.  — Explains the reason for the difference in color perception.
  6. What color are the stars?, Mitchell Charity. Accessed online March 19, 2008.
  7. Glenn LeDrew (February 2001). "The Real Starry Sky". Journal of the Royal Astronomical Society of Canada 95 (1 (whole No. 686, February 2001), pp. 32–33. Note: Table 2 has an error and so this article will use 824 as the assumed correct total of main-sequence stars). 
  8. R. O. Gray, et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–70. doi:10.1086/504637. 
  9. Øystein Elgarøy, Oddbjørn Engvold, Niels Lund (March 1999). "The Wilson-Bappu effect of the MgII K line - dependence on stellar temperature, activity and metallicity". Astronomy and Astrophysics 343: 222–228. 

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