Celestron GPS and Auto Guider

[Fdny714]

Can anyone tell me, what is the difference between an " Auto Guider" and "GPS" unit for my Celestron C8-S Advanced GT SLT

I am new to the hobby, and have the above scope with gps but was wondering what an auto guider was for.

[rowan46]

Welcome to sgl. An auto guider is essentially a camera that locks onto a target star and tells the scope to keep it trained on that spot thus enabling you to take long exposure photo's. your mount needs to be able to be guided. sorry for the very simplified explanation but as I don't do imaging I am not really aufait with the exact procedure. essentially it continuously inputs commands to the mount electronically thus enabling clear pictures.

[david o]

The GPS tells the 'scopes on-board computer where on Earth it is.

The Auto Guider, if I'm not mistaken, is to do with controlling the tracking of the mount with a guide-scope during imaging sessions.

[Fdny714]

Thanks so much for the responses.. So in essence now I need another scope on top of this scope with an auto guider ? Geez this is getting expensive already and I haven't even turned it on

[Fdny714]

Shouldn't this scope with gps guide it self and stay locked onto whatever I am filming ?

[david o]

Hi Fdny,

I'm afraid that astro-photography can be a very expensive part of our hobby.

If the mount is properly set up and accurately aligned, normal tracking will let you take short(ish) exposures. Auto guiding is optional and helps with taking long exposure shots. At least, if I'm not mistaken, it's an Eq mount... that avoids some complications - you'll be able to track the stars properly.

For getting started you'll find the book Making Every Photon Count (by SGL's very own steppenwolf & now onto it's 2nd Edition) helpful. Easy to read, it's full of advice aimed at the imaging novice, including choosing the right equipment, tips 'n' tricks and lots of other vital stuff.

The imaging section, too, is full of lots of info and some very experienced, talented folk who, I'm sure, will be more than happy to share advice and guidance with you.

HTH

[Fdny714]

Thanks again for the response... I will look into the items you mentioned.. Much appreciated

[rowan46]

Gps gives your position on the earth and consequently makes your computers skymap more accurate in relation to you. This is great for finding objects.

But unfortunately all mounts have a small amount of error called periodic error on them.

Think of it like a watch your average watch loses or gains a second or 2 a day this can mean at the end of the year your watch could be 12mins out. new radio watches reset themselves every day consequently your watch is never more than a second out during a 1 day period. The auto guider is like the radio signal which resets your watch. it sends the signal repeatedly and often to the mount constantly resetting it thus negating the mounts errors. result a picture which is absolutely steady and clear. If you want to do long exposure work you have to have it guided.

[Fdny714]

Ok thank you for that... So to start I can just use it UNGUIDED then after I get used to it purchase an auto guider ?

[david o]

Yes... and only if you choose a style of imaging that requires auto-guiding.

[rowan46]

yes. but if you want to take any pic longer than say 20-30 secs you're going to need an autoguider.