guiding & taking multiple images.

[Joshua Bunn (Joshua)]

He everyone.

When one says they set their mount, let it image unatended and go and do something else for some hours, can the software take a series of exposures automaticaly or will it only take one long one? If it will take a series, can ccdsoft, ccdops do this?

Does anyone know if the lx200 acf's can be programed to auto sleep or auto stop at the end of an imaging sesion - is it the software that comes with the camera the thing that controls this? (im using - about to use, the standard software that comes with the SBIG stl-11000).

Also, when auto guiding (throught the scope or seperate guide scope) will it guide on a target for some time or does periodic error accumulate and the target ends up being way off. I presume it will guide for some time - as people do set and forget so to speek .

thanks
Josh

[bmitchell82 (Brendan)]

You are right,

there are many different programs that will do this for you. Alot of people like to use MaximDL, others include Nebulosity, CCDsoft etc etc.

As for guiding and PE

Guiding will hold onto a star untill either clouds come, something bad happens or you have to flip over to the other side of the meridian, but you wont have to do that so much as the forks allow you to track from one side to the other.

PE is Periodic Error, its basically defects in manufacturing that is inherent in all mounts to some degree. If you are to look at most GEM they will state that the PE is +- 5 arc seconds or something like that. What they are actually saying is that if you have perfect polar alignment and let the mount go un guided the star will drift a maximum of 5 seconds of arc either way. So as you can well imagine thats why people try to get that number as small as possible so that the guiding is just nudging the mount here and there not going all out just to hold onto the star and then when the wind pops its head into the mix the guiding cant hold on and then you get eggy stars. It will not accumulate.

[Joshua Bunn (Joshua)]

thanks Brendan,

How was Tamin - i presume you went.

[Peter.M]

Like Brendan says PE will cause the star to move slightly when tracking, due to mechanical errors in the gears. What guiding does is catch the mount back up to the star, because the star will then be centered again the next time periodic error rears its ugly head the mount only has that small distance to catch up again which is why it does not accumulate.

[bmitchell82 (Brendan)]

Peter your not quite right on that theory, the guider does bring it back to the "datum" but PE will never accumulate. You will have more errors due to drift that does accumulate from not quite perfect alignment to the SCP which non of us can actually say we have perfect alignment.

Tammin was a write off i took 2 photos total and both where football stars because of the wind. The cloud and smoke where the nail in the coffin so to speak and i had packed up by 2am!