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Astronomers

A group for people who enjoy the stars. :)

Members: 164
Latest Activity: Jan 19

Discussion Forum

Possible shape of the universe

Started by Donald L. Engel. Last reply by Donald L. Engel Jan 19. 8 Replies

All things Pluto

Started by Joan Denoo. Last reply by Gerald Payne Sep 17, 2015. 2 Replies

The Five Planets in the Sky.

Started by Visvakarman Svetasvatara-Upanish Jun 17, 2015. 0 Replies

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Comment by Gerald Payne on May 16, 2015 at 7:36am

The milky way and Andromeda galaxies, set to collide in 4 billion years may already be in contact. Using the Hubble telescope scientists have discovered a halo of gas surrounding Andromeda that's 2 light years in diameter. Being 2 light years distant, a similar halo around our galaxy would mean contact has already begun.

Quasars are the brightest objects in the Universe and so distant, relative to Andromeda that from them has to pas through Andromeda's halo. Light showed a minute dip at selected wavelengths as  it passed through the halo en route to Hubble

To detect Andromeda's halo, Lehner and team studied how the light of 18 quasars (five shown here) was absorbed by the galaxy's gas. Credit: NASA

Comment by Gerald Payne on May 1, 2015 at 7:19am

Sending a probe to Mercury was the most challenging mission they've ever tried. The gravitational well of the Sun is so strong that the inner Planets, although the closest, are the most difficult to reach. It was estimated that a direct spaceflight to Mercury would need to burn so much fuel to check it's momentum there'd be no room for the scientific instruments!

Comment by Gerald Payne on May 1, 2015 at 6:57am

When we consider that they have only a 50 mile 'window' to hit to get the sling right after millions of miles of travel, with everything moving under the influence of gravity, it's no small feat.

Comment by Idaho Spud on May 1, 2015 at 6:34am

I'm often amazed at what scientists have accomplished.

Comment by Gerald Payne on May 1, 2015 at 6:30am

I think it took something like 8 years to get there Idaho, using planetary slingshot manoeuvers, first out to Jupiter and then slinging back to Earth to Venus back to Earth and so on to slow the spacecraft down before it fell into the gravitational well of the Sun.

Comment by Idaho Spud on May 1, 2015 at 6:06am

Messenger slammed into Mercury at 3:27 PM ET.  It was on the other side from us, so we got no pictures of it.  Other telescopes in space could not get pictures because they would have been looking into the sun.

But it was a sucess.  Like several other missions, it exceeded it goal.  It's original goal was to take 2,500 images of the planet, but it has returned more than 270,000 to earth.

Comment by Gerald Payne on April 30, 2015 at 4:11pm

Today Mercury will have a new crater, the messenger probe will collide with the surface creating a crater 16 metres wide. John Lennon has had a mercurial crater named after him.

Comment by Gerald Payne on April 25, 2015 at 12:57pm

I think I will have to work out a way as you say with a longer length tripod and an observing chair. As you say at different altitudes your bound to get varying degrees of comfort no matter where the eyepiece is situated.

Comment by Gregg on April 25, 2015 at 10:45am

Regardless of the type of telescope you have, they are sometimes going to be in positions where the eyepiece is in an awkward position.  I personally use a 10" Schmidt-Cassegrain on a fork mount and when looking directly overhead, the eyepiece is low although it's not as bad as a refractor scope would be.  The short tube length of the SC helps keep the eyepiece within a relatively small area (The tube length is only around 15" long, but it has a focal length of 2500mm.  However, by carefully adjusting the tripods leg length and using an observing chair, I usually don't have any problems.  I also have an 8" Newtonian which is better than a refractor as far as eyepiece comfort is concerned.  But since the eyepiece is at the front end of the scope instead of the back, there have been times I've had to use a step stool to reach the eyepiece and I'm 6' 2" tall.  I've used about every telescope style and mount and for observation, I prefer the SC for mount to anything else.

Comment by Gerald Payne on April 24, 2015 at 7:16pm

I've got an equatorial 5 but as I say unless I'm gonna get easier access to the eyepiece it would be pointless swapping.

 

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