How to spot Uranus

Homer Hotspur · Post by **Homer Hotspur** » Mon Sep 29, 2008 4:54 pm

I spent a large part of my observing this weekend trying to find Uranus without success(I think). I took my lead from Stellarium and traced a line roughly down from the centre of the square of Pegasus. I simply could not spot anything like a planet. What should I be looking for?

goodtime · Post by **goodtime** » Mon Sep 29, 2008 5:00 pm

I'm not sure you'll be able to see anything other than another 'star', it's just too far away for smaller scopes to resolve the disk. You probably saw it but didn't realize it...

I'm sure some of the other people here will clarify the situation.

jeff.stevens · Post by **jeff.stevens** » Mon Sep 29, 2008 9:33 pm

I think you'd need to view it at high magnifications, in excess of x100, to resolve Uranus as a disc. I've only ever seen it as a star-like point of light using a binocular.

If you search the forums on here you'll be able to read about other people's experience of finding the planet; a couple of examples can be found here and here.

Mike Feist wrote a brief guide to observing Uranus on the Planetary Section pages, which can be found here. There's also an interesting article on the Sky and Telescope website, which can be found here.

Jeff.

astroeddie · Post by **astroeddie** » Tue Sep 30, 2008 9:56 am

Hi Homer,

The view of Uranus using your scope, 120mm Refractor, looks rather like a Planetary Nebulae, NGC 6210 especially. Get the bright stars to a pint point, Uranus looks like a " lime green" out of focus star.

If you have a printed Star Chart, then make a wire circle that fits your FOV with whatever you're using. Then find a bright field star to begin star hopping, matching the stars in the FOV with what you see in the wire circle. Once located and you're used to what the Ice Giant looks like, its pretty much a doddle to find. I use 15 x 70's binos.
The moons are another matter and will require imaging.

Good luck on your quest.... keep us all posted.

Eddie H

mike a feist · Post by **mike a feist** » Tue Sep 30, 2008 1:33 pm

If you are using an adequate map (like stellarum) locating Uranus should be easy BUT it will only look like a faint star in small hand-held optics. Currently as a rough guide: locate phi by using the obvious pattern of the three psi stars - 1,2 and 3. To the left, and slightly above, phi is the fainter star 96 Aquarii. Now go the same distance beyond 96 and a bit downwards and you will find Uranus (about as bright as 96) making a very flatterned isosceles triangle with the two stars mentions.
Immediate proof can be had by using high magnification on a telescope (as mentioned by others) but a slower proof can be done by following it for a couple of weeks as the planet approaches these stars. maf

billden · Post by **billden** » Tue Sep 30, 2008 9:11 pm

I`ve observed Uranus on 18th and 28th of Sept and both times it`s blue/green colour has made it obvious to me. When I viewed it at 136x a definite disc could be made out. I noticed that from where I am the sky
was not very transparent making it very difficult to see any background stars to match in a finder chart.

Lady Isabella · Post by **Lady Isabella** » Wed Oct 01, 2008 12:41 pm

Hi

An interesting thing about Uranus, is that it can undergo short term changes in brightness, making it brighter than the stated magnitude.
More than a quarter of a century ago, I was involved in checking for such changes with other keen observers. Some used photoelectric photometry,
while I was one of the visual observers.

coldfieldboundary · Post by **coldfieldboundary** » Thu Oct 02, 2008 10:07 am

interesting!! Tell us more! How many magnitudes were these changes? Do you mean Uranus as a star, I can't imagine it was the disk itself? Is it known what's causing this?

Post by **Paul Sutherland** » Thu Oct 02, 2008 10:47 am

coldfieldboundary wrote: interesting!! Tell us more! How many magnitudes were these changes? Do you mean Uranus as a star, I can't imagine it was the disk itself? Is it known what's causing this?

The SPA Variable Star Section used to include Uranus in its observing programme and we checked its brightness in the same way that we did stars. I'm not sure we ever came up with any great conclusions but any fluctuations in brightness were only in the manner of tenths of a magnitude. Presumably due to differing brightness of its clouds.

Lady Isabella · Post by **Lady Isabella** » Thu Oct 02, 2008 3:05 pm

Hi

The changing brightness was due to various ices in the upper atmosphere of the planet. If I remember correctly, the biggest change was half a magnitude, making the planet easier to see with the naked eye.