Hydrus - Revision history

Sushoff at 12:30, 27 February 2026

2026-02-27T12:30:24Z

← Older revision		Revision as of 12:30, 27 February 2026
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	=== Origin of Constellation ===		=== Origin of Constellation ===
	[[File:DeHoutman VVaterslang.jpg\|thumb\|screenshot of de Houtman's 1603 first catalogue of stars in Hydrus; notethe typesetting of the "W" featured as 2 "V"s.]]		[[File:DeHoutman VVaterslang.jpg\|thumb\|screenshot of de Houtman's 1603 first catalogue of stars in Hydrus; notethe typesetting of the "W" featured as 2 "V"s.]]
	It seems that the Dutch navigators, Pieter Keyser and Frederick de Houtman, who navigated the Eerste Schipvaart from Europe via Madagasscar to the East Indies, continued the line of the ancient river southwards to the star [[Achernar]] and evern further south. Hydrus begins next to Achernar, the brightest star in the constellation River. The star we call Achernar today was added to the river only in early modern times. The Arab Bedouins may have used it for orientation a few centuries earlier. However, the Arabic name Achernar for ‘end of the river’ was transferred from ϑ Eridani to this star in early modern times and refers to the Ptolemaic constellation The River ([[Eridanus]]).		<ref>Hoffmann, Susanne M. Wie der Löwe an den Himmel kam. Franckh Kosmos Verlag, Stuttgart 2021</ref>It seems that the Dutch navigators, Pieter Keyser and Frederick de Houtman, who navigated the Eerste Schipvaart from Europe via Madagasscar to the East Indies, continued the line of the ancient river southwards to the star [[Achernar]] and evern further south. Hydrus begins next to Achernar, the brightest star in the constellation River. The star we call Achernar today was added to the river only in early modern times. The Arab Bedouins may have used it for orientation a few centuries earlier. However, the Arabic name Achernar for ‘end of the river’ was transferred from ϑ Eridani to this star in early modern times and refers to the Ptolemaic constellation The River ([[Eridanus]]).

	==== Navigational Tool? ====		==== Navigational Tool? ====

Sushoff at 13:24, 20 January 2026

2026-01-20T13:24:22Z

← Older revision		Revision as of 13:24, 20 January 2026
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			Authors: {{PAGEAUTHORS}}
			----
	[[File:Hydrus IAU.svg\|alt=star chart\|thumb\|star chart,CC BY IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)]]		[[File:Hydrus IAU.svg\|alt=star chart\|thumb\|star chart,CC BY IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)]]
	[[File:Plancius-hydrus hi.jpg\|thumb\|Hydrus in Plancius (1596): it is obvious that he reworked the tail of the snake. ]]		[[File:Plancius-hydrus hi.jpg\|thumb\|Hydrus in Plancius (1596): it is obvious that he reworked the tail of the snake. ]]

Sushoff: /* Navigational Tool? */

2025-05-03T19:18:29Z

Navigational Tool?

← Older revision		Revision as of 19:18, 3 May 2025
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	The shape of the curls close to the head of Hydrus resembles the shape of the northern part of Eridanus (close to Orion's foot), and the curved line meanders down to the south pole (marked on the map as the cross section of the colure circles). The tip of the water '''snake's tail is next to the South Pole.''' This view seems to be supported by '''Paulus Merula''' in his ''Cosmographiae generalis libri tres'' (1605) as one of the name alternatives he gives as "'''Hydrus Polaris'''".		The shape of the curls close to the head of Hydrus resembles the shape of the northern part of Eridanus (close to Orion's foot), and the curved line meanders down to the south pole (marked on the map as the cross section of the colure circles). The tip of the water '''snake's tail is next to the South Pole.''' This view seems to be supported by '''Paulus Merula''' in his ''Cosmographiae generalis libri tres'' (1605) as one of the name alternatives he gives as "'''Hydrus Polaris'''".

	~~However~~, ~~the~~ celestial globe by Blaeu ~~1605 (~~who directly used de Houtman's original data) the ~~image is not that clear~~. So perhaps, the curly watery line pointing due south is a creation by Plancius, Hondius or Bayer: Plancius's had corrected the southern end of Hydrus for his 1598 globe. A draft of the globe gores that dates a few years ealier shows that his original version almost touched the south pole, too - and Bayer probably had access to the earlier version and perhaps to Merula's terminlogy.		The celestial globe by Plancius and Hondius (1598) is lost, but preserved is a copy of it by Blaeu (1602). A year later, Blaeu made a second globe. The celestial '''globe by Blaeu''' 1603 who directly used de Houtman's original data, again changed the tail of Hydrus - now pointing upwards/ forward in the image (northeastwards), but still conisting of the same stars<sup>?</sup>.

			So perhaps, the curly watery line pointing due south is a creation by Plancius, Hondius or Bayer: Plancius's had corrected the southern end of Hydrus for his 1598 globe. A draft of the globe gores that dates a few years ealier shows that his original version almost touched the south pole, too - and Bayer probably had access to the earlier version and perhaps to Merula's terminlogy.

	==== De Houtman's Version ====		==== De Houtman's Version ====
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	* Bayer (1603) draws the tail tip of Hydrus as a marker of the south pole.		* Bayer (1603) draws the tail tip of Hydrus as a marker of the south pole.

	* On Blaeu’s globe of 1602, copied from Plancius and Hondius, it follows much the same path as on Bayer’s atlas, but without Bayer's artistic coils.		* On Blaeu’s globe of 1602, copied from Plancius and Hondius (1598), it follows much the same path as on Bayer’s atlas, but without Bayer's artistic coils.
	* Blaeu made a second globe the following year, this time from de Houtman’s catalogue. On this globe the tail of Hydrus ends in quite a different position, under the feet of Pavo and pointing away from Apus.		* Blaeu made a second globe the following year, this time from de Houtman’s catalogue. On this globe the tail of Hydrus ends in quite a different position, under the feet of Pavo and pointing away from Apus.
	* In de Houtman’s catalogue the tip of the tail ended at the star we now know as ν Octantis, which is actually the brightest star in Octans.		* In de Houtman’s catalogue the tip of the tail ended at the star we now know as ν Octantis, which is actually the brightest star in Octans.

Sushoff at 19:06, 3 May 2025

2025-05-03T19:06:02Z

← Older revision		Revision as of 19:06, 3 May 2025
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	==== De Houtman's Version ====		==== De Houtman's Version ====
	[[File:Blaeu1603 Hydrus.JPG\|thumb\|Blaeu (1603), based on de Houtman's data, Hydrus changed]]		[[File:Blaeu1603 Hydrus.JPG\|thumb\|Blaeu (1603), based on de Houtman's data, Hydrus changed [https://collections.rmg.co.uk/mediaLib/398/media-398216/large.jpg (RMG)].]]
	Due to political circumstances, the original author, Frederick de Houtman, published his star catalog only in 1603 - after the first globe by Plancius and Hondius and simultaneously with Bayer's Uranometria.		Due to political circumstances, the original author, Frederick de Houtman, published his star catalog only in 1603 - after the first globe by Plancius and Hondius and simultaneously with Bayer's Uranometria.

Sushoff at 19:04, 3 May 2025

2025-05-03T19:04:02Z

← Older revision		Revision as of 19:04, 3 May 2025
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	==== De Houtman's Version ====		==== De Houtman's Version ====
			[[File:Blaeu1603 Hydrus.JPG\|thumb\|Blaeu (1603), based on de Houtman's data, Hydrus changed]]
	Due to political circumstances, the original author, Frederick de Houtman, published his star catalog only in 1603 - after the first globe by Plancius and Hondius and simultaneously with Bayer's Uranometria.		Due to political circumstances, the original author, Frederick de Houtman, published his star catalog only in 1603 - after the first globe by Plancius and Hondius and simultaneously with Bayer's Uranometria.

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	File:Hydrus Plancius+Hondius.JPG\|Hydrus on the celestial globe by Plancius/ Hondius (1597/8)		File:Hydrus Plancius+Hondius.JPG\|Hydrus on the celestial globe by Plancius/ Hondius (1597/8)
	File:Plancius-hydrus hi.jpg\|Hydrus in Plancius (1598). Note that the end was reworked: the first (erased) version went towards the pole, just like Bayer's (1603) version.		File:Plancius-hydrus hi.jpg\|Hydrus in Plancius (1598). Note that the end was reworked: the first (erased) version went towards the pole, just like Bayer's (1603) version.
	File:Hydrus Blaeu.JPG\|Hydrus on Blaeu's Globe (Willem Jansz.Blaeu, ~~1602~~).		File:Hydrus Blaeu.JPG\|Hydrus on Blaeu's Globe (Willem Jansz.Blaeu, 1603, second globe, based on de Houtman's data).
	File:1024px-Johann Bayer - Uraniometria - Hydrus.jpg\|Bayer (1603): Constellation Hydrus (CC0)		File:1024px-Johann Bayer - Uraniometria - Hydrus.jpg\|Bayer (1603): Constellation Hydrus (CC0)
	File:Hydrus Keere+Plancius1612.JPG\|Hydrus on the van der Keere & Plancius (1612) globe, it does not deviate from Plancius' 1598 version.		File:Hydrus Keere+Plancius1612.JPG\|Hydrus on the van der Keere & Plancius (1612) globe, it does not deviate from Plancius' 1598 version.

Sushoff at 14:10, 3 May 2025

2025-05-03T14:10:15Z

← Older revision		Revision as of 14:10, 3 May 2025
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	=== Origin of Constellation ===		=== Origin of Constellation ===
	[[File:DeHoutman VVaterslang.jpg\|thumb\|screenshot of de Houtman's 1603 first catalogue of stars in Hydrus; notethe typesetting of the "W" featured as 2 "V"s.]]		[[File:DeHoutman VVaterslang.jpg\|thumb\|screenshot of de Houtman's 1603 first catalogue of stars in Hydrus; notethe typesetting of the "W" featured as 2 "V"s.]]
	It seems that the Dutch navigators, Pieter Keyser and Frederick de Houtman, who navigated the Eerste Schipvaart from Europe via Madagasscar to the East Indies, continued the line of the ancient river southwards to the star Achernar and evern further south. Hydrus begins next to Achernar, the brightest star in the constellation River. The star we call Achernar today was added to the river only in early modern times. The Arab Bedouins may have used it for orientation a few centuries earlier. However, the Arabic name Achernar for ‘end of the river’ was transferred from ϑ Eridani to this star in early modern times and refers to the Ptolemaic constellation The River ([[Eridanus]]).		It seems that the Dutch navigators, Pieter Keyser and Frederick de Houtman, who navigated the Eerste Schipvaart from Europe via Madagasscar to the East Indies, continued the line of the ancient river southwards to the star [[Achernar]] and evern further south. Hydrus begins next to Achernar, the brightest star in the constellation River. The star we call Achernar today was added to the river only in early modern times. The Arab Bedouins may have used it for orientation a few centuries earlier. However, the Arabic name Achernar for ‘end of the river’ was transferred from ϑ Eridani to this star in early modern times and refers to the Ptolemaic constellation The River ([[Eridanus]]).

	==== Navigational Tool? ====		==== Navigational Tool? ====

Sushoff: /* Etymology and History */

2025-05-03T14:04:15Z

Etymology and History

← Older revision		Revision as of 14:04, 3 May 2025
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	Due to political circumstances, the original author, Frederick de Houtman, published his star catalog only in 1603 - after the first globe by Plancius and Hondius and simultaneously with Bayer's Uranometria.		Due to political circumstances, the original author, Frederick de Houtman, published his star catalog only in 1603 - after the first globe by Plancius and Hondius and simultaneously with Bayer's Uranometria.

	The southernmost star in his list is the 11<sup>th</sup> star in the tail of the “Waterslanghe” at declination −83° 40′, now called β Octantis (mag 4.13), as Lacaille (1756) took the stars at the south pole to place a newly invented navigational tool there, the octant ([[Octans]]).		The southernmost star in his list is the 11<sup>th</sup> star in the tail of the “Waterslanghe” at declination −83° 40′, now called β Octantis (mag 4.13), as Lacaille (1756) took the stars at the south pole to place a newly invented navigational tool there, the octant ([[Octans]]). This is not compatible with both contemporary globes by Plancius and Bayer: in Plancius, the third and fourth star are closest to the pole, and in Bayer, it is the 15th star.
	{\| class="wikitable"		{\| class="wikitable"
	!		!

Sushoff: /* Etymology and History */

2025-05-03T13:59:33Z

Etymology and History

Show changes

Sushoff at 13:21, 3 May 2025

2025-05-03T13:21:26Z

← Older revision		Revision as of 13:21, 3 May 2025
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	[[File:Hydrus IAU.svg\|alt=star chart\|thumb\|star chart,CC BY IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)]]		[[File:Hydrus IAU.svg\|alt=star chart\|thumb\|star chart,CC BY IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)]]
			[[File:Plancius-hydrus hi.jpg\|thumb\|Hydrus in Plancius (1596): it is obvious that he reworked the tail of the snake. ]]
	One of the [[:Category:88_IAU-Constellations\|88 IAU constellations]]. The constellation Hydrus, known as the Lesser Water Snake, is located in the southern celestial hemisphere, positioned between the Large and Small Magellanic Clouds. It is notable for being near the celestial south pole.		One of the [[:Category:88_IAU-Constellations\|88 IAU constellations]]. The constellation Hydrus, known as the Lesser Water Snake, is located in the southern celestial hemisphere, positioned between the Large and Small Magellanic Clouds. It is notable for being near the celestial south pole.

Sushoff: /* Transfer and Transformation of the Constellation */

2025-05-03T13:19:31Z

Transfer and Transformation of the Constellation

← Older revision		Revision as of 13:19, 3 May 2025
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	File:Hydrus Blaeu.JPG\|Hydrus on Blaeu's Globe (Willem Jansz.Blaeu, 1602).		File:Hydrus Blaeu.JPG\|Hydrus on Blaeu's Globe (Willem Jansz.Blaeu, 1602).
	File:1024px-Johann Bayer - Uraniometria - Hydrus.jpg\|Bayer (1603): Constellation Hydrus (CC0)		File:1024px-Johann Bayer - Uraniometria - Hydrus.jpg\|Bayer (1603): Constellation Hydrus (CC0)
			File:Hydrus Keere+Plancius1612.JPG\|Hydrus on the van der Keere & Plancius (1612) globe, it does not deviate from Plancius' 1598 version.
	File:Lacaille’s southern planisphere of 1756.png\|In Lacaille's map of the celestial south (1756), the tail of Hydrus is modified to place Octans (a newly invented nautical instrument) at the celestial south pole		File:Lacaille’s southern planisphere of 1756.png\|In Lacaille's map of the celestial south (1756), the tail of Hydrus is modified to place Octans (a newly invented nautical instrument) at the celestial south pole
	File:Hyi Fortin1795.jpg\|Hydrus in Fortin's Atlas Céleste, 3rd edition (1795).		File:Hyi Fortin1795.jpg\|Hydrus in Fortin's Atlas Céleste, 3rd edition (1795).

← Older revision		Revision as of 19:04, 3 May 2025
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	==== De Houtman's Version ====		==== De Houtman's Version ====
			[[File:Blaeu1603 Hydrus.JPG\|thumb\|Blaeu (1603), based on de Houtman's data, Hydrus changed]]
	Due to political circumstances, the original author, Frederick de Houtman, published his star catalog only in 1603 - after the first globe by Plancius and Hondius and simultaneously with Bayer's Uranometria.		Due to political circumstances, the original author, Frederick de Houtman, published his star catalog only in 1603 - after the first globe by Plancius and Hondius and simultaneously with Bayer's Uranometria.

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	File:Hydrus Plancius+Hondius.JPG\|Hydrus on the celestial globe by Plancius/ Hondius (1597/8)		File:Hydrus Plancius+Hondius.JPG\|Hydrus on the celestial globe by Plancius/ Hondius (1597/8)
	File:Plancius-hydrus hi.jpg\|Hydrus in Plancius (1598). Note that the end was reworked: the first (erased) version went towards the pole, just like Bayer's (1603) version.		File:Plancius-hydrus hi.jpg\|Hydrus in Plancius (1598). Note that the end was reworked: the first (erased) version went towards the pole, just like Bayer's (1603) version.
	File:Hydrus Blaeu.JPG\|Hydrus on Blaeu's Globe (Willem Jansz.Blaeu, ~~1602~~).		File:Hydrus Blaeu.JPG\|Hydrus on Blaeu's Globe (Willem Jansz.Blaeu, 1603, second globe, based on de Houtman's data).
	File:1024px-Johann Bayer - Uraniometria - Hydrus.jpg\|Bayer (1603): Constellation Hydrus (CC0)		File:1024px-Johann Bayer - Uraniometria - Hydrus.jpg\|Bayer (1603): Constellation Hydrus (CC0)
	File:Hydrus Keere+Plancius1612.JPG\|Hydrus on the van der Keere & Plancius (1612) globe, it does not deviate from Plancius' 1598 version.		File:Hydrus Keere+Plancius1612.JPG\|Hydrus on the van der Keere & Plancius (1612) globe, it does not deviate from Plancius' 1598 version.

← Older revision		Revision as of 13:21, 3 May 2025
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	[[File:Hydrus IAU.svg\|alt=star chart\|thumb\|star chart,CC BY IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)]]		[[File:Hydrus IAU.svg\|alt=star chart\|thumb\|star chart,CC BY IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)]]
			[[File:Plancius-hydrus hi.jpg\|thumb\|Hydrus in Plancius (1596): it is obvious that he reworked the tail of the snake. ]]
	One of the [[:Category:88_IAU-Constellations\|88 IAU constellations]]. The constellation Hydrus, known as the Lesser Water Snake, is located in the southern celestial hemisphere, positioned between the Large and Small Magellanic Clouds. It is notable for being near the celestial south pole.		One of the [[:Category:88_IAU-Constellations\|88 IAU constellations]]. The constellation Hydrus, known as the Lesser Water Snake, is located in the southern celestial hemisphere, positioned between the Large and Small Magellanic Clouds. It is notable for being near the celestial south pole.

← Older revision		Revision as of 13:19, 3 May 2025
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	File:Hydrus Blaeu.JPG\|Hydrus on Blaeu's Globe (Willem Jansz.Blaeu, 1602).		File:Hydrus Blaeu.JPG\|Hydrus on Blaeu's Globe (Willem Jansz.Blaeu, 1602).
	File:1024px-Johann Bayer - Uraniometria - Hydrus.jpg\|Bayer (1603): Constellation Hydrus (CC0)		File:1024px-Johann Bayer - Uraniometria - Hydrus.jpg\|Bayer (1603): Constellation Hydrus (CC0)
			File:Hydrus Keere+Plancius1612.JPG\|Hydrus on the van der Keere & Plancius (1612) globe, it does not deviate from Plancius' 1598 version.
	File:Lacaille’s southern planisphere of 1756.png\|In Lacaille's map of the celestial south (1756), the tail of Hydrus is modified to place Octans (a newly invented nautical instrument) at the celestial south pole		File:Lacaille’s southern planisphere of 1756.png\|In Lacaille's map of the celestial south (1756), the tail of Hydrus is modified to place Octans (a newly invented nautical instrument) at the celestial south pole
	File:Hyi Fortin1795.jpg\|Hydrus in Fortin's Atlas Céleste, 3rd edition (1795).		File:Hyi Fortin1795.jpg\|Hydrus in Fortin's Atlas Céleste, 3rd edition (1795).