Autoguiding

[zumka (Daniel)]

Hi Guys,

I have EQ6PRO with SW600, Nikon D50 SLR and laptop. I am at the point of starting astrophotography.

One small concept I'm still trying to understand is autoguiding.

What is the purpose of autoguiding ?
How is it related to EQ6PRO mount traking?
Is there any relation between RJ-45 port on SyncScan and autoguiding ?

I understand that autoguing evolves widefield scope and CCD camera. I'm assuming that there is no need on spending many $$$$ on autoguing setup.

Which is the best guiding scope and CCD camera to get without going overboard?
Thanks guys.

[bmitchell82 (Brendan)]

From what i have seen, the Orion st80/Autoguider is a good combo, though it really just depends on how much you want to spend.

For me i will be getting a good scope for 3 reasons

-To Guide with
-To Image with
-Grab and go travel scope

Something like a ED 80, WO Zenith star who knows

This is because they will make things alot sharper, and allow the guiding process to work more efficently. but yes, its one of those things.

[zumka (Daniel)]

Originally Posted by bmitchell82

From what i have seen, the Orion st80/Autoguider is a good combo, though it really just depends on how much you want to spend.

For me i will be getting a good scope for 3 reasons

-To Guide with
-To Image with
-Grab and go travel scope

Something like a ED 80, WO Zenith star who knows

This is because they will make things alot sharper, and allow the guiding process to work more efficently. but yes, its one of those things.

Are you referring to Orion autoguider ? ($469 from Bintel) does it have to be so expensive ?

Is there some sort of tutorial how to utilize autoguiding ?

[Dennis]

Hi Daniel

If your mount can Track and Auto guide, here is what it means:

Tracking: the mount is (generally) being driven by motors at the sidereal rate; that is, the rate at which the Earth rotates, so it will make 1 complete rotation (360 degrees) in 23h 56m.

Auto guide: Here, a dedicated CCD camera is monitoring, in real time, the position of a (guide) star and if the guide star drifts off its calibrated position, the auto guider unit sends commands to the telescope drive system to “nudge” the guide star back to its calibrated position. This will be done tirelessly and accurately every few seconds.

For long focal lengths, say over 800mm, most mounts will not be able to follow a star and keep it centred on a pixel for longer than, say, 60 seconds by tracking alone. There are mechanical tolerances in the gear train, effects due to refraction of the star by the Earth’s atmosphere, etc, etc, that will contribute to the star drifting when the mount is only tracking. This will give you trailed stars in your image.

However, when auto guiding, these small tracking errors can be generally “catered for” by the guide system making small corrections every few seconds. Generally, the more expensive (high end) mounts have smoother gears, tighter tolerances, better materials and design and superior manufacturing so that they can track for longer periods and still produce round stars (depending on focal length of scope) before you have to kick in with auto guiding.

Cheers

Dennis

[bmitchell82 (Brendan)]

Originally Posted by zumka

Are you referring to Orion autoguider ? ($469 from Bintel) does it have to be so expensive ?

Is there some sort of tutorial how to utilize autoguiding ?

Thats the Tube, CCD,Rings the kit to get you guiding. that is cheap.! Like dennis said, without it kiss any longer than 30 seconds --->1 minute good by when imaging!

I know for a fact my guiding system will end up costing around 700-1000 depending on the CCD guider i use. but i will have 2 good telescopes and 2 good CCD's one in which i will be able to take terrestrial photos with. so I guess its what you see value in. if you want good photos. tracking is essential, if your p155 farting around and just want to tinker a bit, then go unguided.

For the most part i woudl'nt run Autoguiding, because you can use your guide scope for Polar alignments so run it though your PC then you can see whats actually happening! So just run it as a guide scope set up where you manually setup the guide star and let it rip.

As for where you plug it in and the ports. your guide scope will run directly out of the CCD and into your PC thats the easiest way to operate, there is a standard rj12 port that accepts ST4 commands (auto guider) and you will need something called GPUSB (Guide port to usb) sold by shoestring astronomy. this converts the signal from usb back to the serial connection (rj12).