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Uranus Observation (July 29, 2010)

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#1 CarlosEH

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Posted 06 August 2010 - 07:03 PM

I made an observation of Uranus on July 29, 2010 (05:30 U.T.) using my 9-inch (23-cm) F.13.5 Maksutov-Cassegrain (310x). The small pastel green (or teal) disk of Uranus was very sharp at even higher magnification but I chose to examine it at moderate amplification. The center of the disk appeared to exhibit a faint dusky to dull (4-5/10) bar with a brightening (6-7/10) over the polar regions. These faint albedo features were not easy to detect but patience at the eyepiece allowed me to detect them. I hope that everyone gets a look at the Georgian planet.

A digital image produced in Pixelmator.

Carlos

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#2 CarlosEH

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Posted 06 August 2010 - 07:07 PM

Jupiter and Uranus are now approximately three degrees apart. They should be visible in the same field of a 7 x 50 mm binoculars under dark skies. I have attached a diagram of the pair obtained from Stellarium (0.10.5).

Carlos

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#3 Sol Robbins

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Posted 06 August 2010 - 08:03 PM

Great sketch Carlos. Uranus is one of those planets that folks digress about regarding seeing any kind of detail. I have have seen detail twice in all the years

I have observed the planet very similar to what you present here in my 10" at very high magnification. 400x or so.

This sketched observation is excellent. I guess my only question is regarding the orientation of north/south and preceding/following. IIRC, Uranus' spin is sideways.

I have never been able to figure out what I'm seeing regarding orientation. Any tips?

Thanks,

#4 Tommy5

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Posted 06 August 2010 - 10:58 PM

Great sketch of uranus it is very hard to see albedo features on uranus,you have calm skies. a great scope and very sharp eyes.

#5 frank5817

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Posted 06 August 2010 - 11:42 PM

Carlos,

Excellent sketch of Uranus.
In all the years I have observed this planet, I never could convinced myself with certainty of seeing any cloudy features. I have always enjoyed trying but I'm sure that planet killer scope of yours and your experience is what it takes.
Fantastic! :bow:

Frank :)

#6 rerun

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Posted 08 August 2010 - 10:43 AM

Hallo Carlos,

I never saw a Uranus Sketch with some details on it.Very good work ,but also a very good scope you have.

CS

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#7 seryddwr

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Posted 10 August 2010 - 09:48 PM

Spectacular, Carlos! That's no mean feat! :bow: I suspect keeping the exit pupil as large as you did would help to reveal low contrast detail.

#8 CarlosEH

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Posted 11 August 2010 - 03:41 AM

Thank you all for the kind compliments on my Uranus observation. This is a difficult planet to detect any type of detail (albedo features) over but at times some faint features are visible if one is patient and experiences a steady atmosphere. Unless one is using a moderate to large aperture (> 8-10 inches (20-25 cm.)) filters may not be helpful to detect any albedo features visible.

Uranus, the seventh planet in the solar system, was discovered on March 13, 1781 by the Anglo-German astronomer (1738-1822) near the southern horn of Taurus (Zeta Tauri). Uranus had actually been observed by several observers prior to the discovery date. John Flamsteed (1646-1719, First Astronomer Royal (1675-1719)) first noted the planet as 34 Tauri in 1690 and recorded it on four occasions at later dates (twice in 1712 and 1715). The French astronomer Pierre Charles LeMonnier (1715-1799) observed it on thirteen occasions between 1750 and 1771! (one of his observations was even made upon a paper bag!).

Sir William Herschel initially reported Uranus to be a "Comet" to the Astronomer Royal at the time, Nevil Maskelyne (1732-1811; Fifth Astronomer Royal from 1765-1811). It was soon afterwards discovered to be the seventh member of the solar system. Herschel wanted to name his discovery Georgium Sidus (George's Star) after his patron King George III of England (1738-1820), but this name was resisted by astronomers from outside of England. It was not officially recognized in England as Uranus until sixty nine years later in 1850 by the HM Nautical Almanac Office.

Links;
http://en.wikipedia.org/wiki/Uranus
http://www.spacestat...s-discovery.htm
http://en.wikipedia..../John_Flamsteed
http://picasaweb.goo...wAW8uLR5TGrr0ZQ

Carlos

#9 CarlosEH

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Posted 11 August 2010 - 04:21 AM

Uranus is the seventh planet from the Sun. This greenish (or teal-colored) gas giant is third largest and fourth most massive planet in the Solar System. Uranus lies approximately nineteen (19) astronomical units (AU) from the Sun (average distance of 1.8 million miles (2.9 million km)). It's orbital elements were first calculated by the French astronomer Pierre-Simon Laplace (1749-1827) in 1783 (also famous for the postulation of the nebular hypotheis of the origin of the solar system in 1796). It was apparent after several decades of tracking Uranus in the heavens that the new planet was not where it was predicted to be in it's orbit. This discrepency stimulated the British astronomer John Couch Adams (1819-1892) to postulate the existence of another planet outside the orbit of Uranus (which therefore perturbed it's orbit) in 1841 as well as by the French astronomer Urbain Jean Joseph Le Verrier (1811-1877) in 1845. From the calculations made by Le Verrier, the planet Neptune was discovered on September 23, 1846 by the German astronomer Johann Gottfired Galle (1812-1910) at the Berlin Observatory with the help of the German astronomer Heinrich Louis d'Arrest (1822-1875), a student at the Berlin Observatory at the time of the discovery, to within one degree of his prediction.

Links;
http://en.wikipedia....illiam_Herschel
http://en.wikipedia....e-Simon_Laplace
http://en.wikipedia....ohn_Couch_Adams
http://en.wikipedia....bain_Le_Verrier
http://en.wikipedia....Gottfried_Galle

Carlos

#10 CarlosEH

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Posted 11 August 2010 - 05:09 AM

Uranus orbits the Sun in a period of eighty-four (84) years. The equatorial diameter of Uranus is 31,770 miles (51,118 km; polar diameter of 31,041 miles (49,946 km)). Approximately four (4) Earths could be placed across it's equator. Uranus is approximately fifteen (specifically 14.5) Earth masses with a density of 1.27 grams per cubic centimeter (g/cm3). The low density of Uranus makes it the second least dense planet in the Solar System after Saturn (0.687 g/cm3). For reasons unknown the axial tilt of Uranus makes it orbit nearly upon it's side (97.8 degrees). This strange axial tilt may have been produced by an early collison between it an an Earth-sized planetesimal among other theories. The magnetic field, discovered by Voyager 2 in 1986 (January 24), was found to be approximately sixty degrees from the axis of rotation and offset by one-third of the planetary radius. According to the International Astronomical Union (IAU) the north pole of a planet is the axis of rotation that lies above the invariable plane of the Solar System. According to the Right-Hand Rule ( http://en.wikipedia....Right-hand_rule ) the north pole lies below the orbital plane with rotation occuring from east to west (retrograde) if observed from space. I have produced a figure below of this lopsided gas giant.

Carlos

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#11 CarlosEH

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Posted 11 August 2010 - 05:39 AM

Uranus revolves around the Sun in a period of eighty four (84) years. Uranus seasons last approximately twenty one (21) years in length. Throughout it's orbit the poles, due to the abnormal inclination (axis), are then in constant sunlight or darkness for a period of nearly forty two (42) years. Uranus is now experiencing Spring over it's northern hemisphere (Northern Vernal Equinox) and Autumn (Southern Autumnal Equinox) over the southern hemisphere. I have produced a diagram showing the seasons of Uranus.

Carlos

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#12 dweller25

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Posted 11 August 2010 - 06:41 AM

Carlos thanks for all the interesting data. It persuaded me to try and observe Uranus which I did early this morning. At x166 I could clearly make out the disk and colour but no shading in my 5" refractor. This is the first time I have ever seen this planet !

#13 lunar

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Posted 11 August 2010 - 02:13 PM

I love your Uranus Sketch. I don't have the magnification needed yet to make sketches of it, but I can sit back and take pictures of it and its sorroundings! :rainbow:

#14 CarlosEH

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Posted 11 August 2010 - 08:43 PM

Brandon and Dweller,

Thank you for the compliments on my Uranus observation and information/history. Uranus is a fascinating planet as it still has many mysteries to solve. Uranus typically does not exhibit albedo features but it never hurts to look for them especially when observing under a steady atmosphere. The best of luck in your own observations of Uranus.

Carlos

#15 NUNKY

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Posted 13 August 2010 - 07:14 AM

Superbe observation !!
Il faudrait que j'essaie avec mon T180.
Penses tu que je puisse voir quelques "détails" et pourquoi pas un satellite ?

#16 azure1961p

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Posted 13 August 2010 - 09:51 PM

I love your Uranus Sketch. I don't have the magnification needed yet to make sketches of it, but I can sit back and take pictures of it and its sorroundings! :rainbow:


Even a simple point and shoot can yield interesting information through the color it records. Going into a photo/image editing program and enlarging the teal-grey "starry" point about 1600x will show the way your camera
recorded the color. From there its interesting to save and compare your pixeled Uranus colors to those made by large telescopes - or in this case - Carlos's fine rendering. Often the pixels have other colors mixed in with the teal that seem to bring the hue together when it is reduced rather than enlarged in photoshop for example.

Its fun and revealing. Color is detail!

Pete

#17 CarlosEH

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Posted 14 August 2010 - 11:41 AM

Nunky and Pete,

Thank you for the compliments on my Uranus observation. Recording the color of an object (e.g. planet, star, or nebula) is important and is considered part of the detail observed, as you point out. The best of luck in your own observations of Uranus.

Carlos

#18 NUNKY

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Posted 14 August 2010 - 12:15 PM

He should try that with my T180.
Do you think I can see some "details" and why not a satellite?

#19 Jef De Wit

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Posted 15 August 2010 - 10:35 AM

Carlos
That's an impressive observation!






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