Telescope upgrade

Chris Taylor wrote:
"Holly, in France" wrote in message
...
Chris Taylor wrote:

I had the 114GT and while it would track an object visually for many
minutes it wasn't able to track an object accurately on its own for
more than about 15 seconds without star trailing becoming an issue.

I might be being a bit dim here, but please could you explain what
you mean in a bit more detail? Thanks,


Take a picture of a distant car with its tail lights on in the
daytime and you'll likely get a picture of; a car with its tail
lights on. Take a picture at night when you need longer exposures and
you're likely to get a blurred trail of tail-lights because you can't
hold the camera steady enough.

In camera speak, your eye takes many short exposures and your brain
compensates for an image moving around a little, kinda like a TV
picture.

Poor tracking of an object with my old 114GT was compensated for
visually by the eye and brain. Imaging/Photography will record all of
the movement of the mount and its tracking and offer an image that
has been moved around proportionally. Stars will begin to show trails
not unlike the tail lights in the example above.

The scope should be good enough for solar system work, where short
exposures are required but will not easily be used for deep sky stuff
where longer exposures are required..

Hope this explains a little more? If not, feel free to shout-up.

Hi Chris, that explains perfectly, thanks. I knew what you meant by star
trailing but hadn't grasped what you meant by the difference between
'visually' and 'on it's own'. Got it now! I have a 114GT too but have
never tried photography with it and as you say, visually it is fine.
Still haven't got the GOTO quite right, but it does track :-)


--
Holly, in France
Gite to let in Dordogne, now with pool.
http://la-plaine.chez-alice.fr