Guiding....

[Tim]

OK, so so far I have had a couple of attempts at using the celestron off axis guider.

Now, I'm not the kind the kind to get bored quickly. No, wait, sorry, I AM that kind. The smiley fellow at David Hinds assured me that was all I needed to be getting started, and I had definite plans to be little tweaky here, little tweaky there with my hand controller as the camera was taking long expo's.

OK, you who know already can stop laughing now. It's just about impossible to find a 'guide' star in the first place, (yep, even in orion), and if you do happen to get lucky, you turn on the illuminated reticle and the star disappears.

At any rate, I'm gonna die of old age, boredom, or exposure before I ever get that blasted thing to work right. SO, what I'm looking for is some more advice on getting my kit to auto guide. Last time you guys cost me thousands, so go easy, i'll tell you what I have to play with, you, please, tell me what I need.

Please bear in mind the weight problem for my mount etc.

Mount = HEQ5 PRO

OTA = C9.25

DSLR = 400D (un modded - somebody write a tutorial!!!)

webcam = Celestron neximage (apparently same as toucam pro?)

Other bits = off axis guider, celestron 60SLT, vista laptop

Im guessing that piggybacking a little scope is the best way? Would the neximage do it? Is the vista laptop ok these days with the mount controlling software? What do you do, centre/align both OTA's with the reticle EP? Are they best both pointed at same target? How best to secure the piggyback ota to assure it doesnt flex too much?

Thanks in advance.

TJ

[cygnusx1]

TJ i threw away my OAG in dis gust too, too much hassle rotating the device looking for guide stars, awkward and never seemed to be able to find a star except Sirius!!

I'd recommend changing to autoguiding, using a webcam (cheap but effective solution ) or a dedicated guider. Others can give you specific detail on guiders/wecabs.

For software try PHD or Guidemaster, both free. MaximDL is good ,but wayyyy too expensive IMO!

You'll need either a serial to RJ12 cable from your laptop to mount handset for guiding (cheaper ) http://www.astronomiser.co.uk/mcc.htm , or a GPINT / GPUSB solution to the ST4 guide port on the mount ( more expensive ) http://www.opticstar.com/Run/Astronomy/Astro-Accessories.asp?s=b0b03b15-db21-4d1d-923b-b1fb0dfc46a&p=0_10_5_0_5 or http://www.astronomiser.co.uk/guide.htm .

Once you've got all that setup in theory your'e A for away.

But, let me add, good luck and welcome to the black art of guiding

I've been at it for months and still haven't mastered it yet :insects1:

[steppenwolf]

Autoguiding is one of the best and most frustrating things that you can do in astrophotography! However, IMHO a second 'scope used as a guide 'scope in the way to go. Your Neximage will be fine to start the ball rolling but a more sensitive CCD would make better sense.

Kevin has pointed you towards suitable software and connecting cables so that is a good place to start. I used to go to a lot of time and trouble using a home made fully adjustable set of collimating rings to hold my guide 'scope so that it was pointing at exactly the same object as the imaging 'scope but in the end found this to be more trouble that it was worth, especially with bright subjects. Now, I simply bolt the guide 'scope to the imaging 'scope in such a manner that it is 'close to pointing in the same direction and that has proved to be more than adequate for the purpose.

It is important to ensure that there is no movement between the guide 'scope and the imaging 'scope as any movement will cause 'differential flexure' which means that the guide 'scope will track correctly but the imaging 'scope may do do so as accurately!) - Kevin uses an elegant but expensive side by side arrangement, I simply attach my guide 'scope to the top of the imaging 'scope.

It is worth persevering with auto-guiding because it is the key to unlocking long exposures.

On a final note, the long distance record for throwing an off axis guider (OAG) currently stands at 123.7 metres, maybe you could better that?

[cygnusx1]

On a final note, the long distance record for throwing an off axis guider (OAG) currently stands at 123.7 metres, maybe you could better that?

[jgs001]

Does this have potential for a new Olympic sport ? OAG Hurling

[Kaptain Klevtsov]

There's two sports that spring to mind. Putting the guider, where it's launched like the shot putt, and the other one is where you totally lose your rag and fling it javelin style. Both these are combined with Laptop discus in the guider's triathlon.

Kaptain Klevtsov

[steppenwolf]

KK, I've got coffee all over my monitor now :D

[Beyond_Vision]

Hi TJ,

I have been using an autoguiding setup for the last few months and it has worked almost flawlessly with exposures of 20 mins with no evidence of trailing at all.

Heres a link to some posts I have made on the subject

http://stargazerslounge.com/index.php/topic,22207.0.html

hope this helps

Kevin

[petevasey]

I used the Celestron Radial Guider successfully for some time before lashing out on an SBIG with guide chip. And never had any problems finding a guide star quite quickly (although occasionally my neck complained!)

The secret is to have an eyepiece parfocal with the guide camera, in my case a modded webcam. Just pop in the eyepiece and fiddle with the mirror and rotate the unit until a star is in the middle of the field. Then replace the guide camera.

I was using Guidedog, so after rotating the guide head it was necessary to align the guide camera with the telescope axes. But some guiding software (PHD Guiding for example) compensates for that automatically. No more flexure/mirror shift problems, no guide scope and the full aperture of the main telescope for the guide star. Never failed!

Cheers, Peter.