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All things Pluto

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

The Five Planets in the Sky.

Started by Visvakarman Svetasvatara-Upanish Jun 17. 0 Replies

From movie graphics to scientific tool

Started by Ruth Anthony-Gardner. Last reply by Joan Denoo Mar 26. 3 Replies

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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.

Comment by Gerald Payne on April 24, 2015 at 7:12pm

A doublet.

Comment by Mick Ohrberg on April 24, 2015 at 7:06pm

Gerald - the Newtonians have one big drawback: The eyepiece can end up in really backbreaking positions, depending on if you have an alt-az mount. If you have a GEQ mount you can normally rotate the scope in the mounting rings to get the ep in a good spot for you. 

Is your refractor a doublet or a triplet? A 150mm refractor scope could command a fair price, depending on the optics configuration.


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