banging my head against a brick wall.

[cosmicdonkey]

Hi guys please help me if you can. I have spent the last few nights trying to get my off axis guider to locate a star. The camera I am using is a dfk21au618 with an Orion off axis guider all loaded on to a c9.25. I think I might be going wrong with the camera. There is just so much noise with this camera. My main imaging camera is an Orion g3 which takes nice crisp pictures of stars. I have seen people say the have had success with the dfk21 but am wondering if I should buy a proper guide cam. I tried achieving focus with both cameras during the day but litterally could not tell if the guide cam was focused or not. Do you think I should retire the dfk back to just planetary imaging and buy I proper dedicated guide cam or perhaps even change my off axis guider as I have read mixed reviews about it?

Am interested to hear your opinions and if you have a similar setup, what do you use?

[lukebl]

I'd say that the problem is that the field of view is simply too narrow for the DFK to find a suitable guide star. The DFK has a very small sensor, and the 9.25 has a pretty long focal length, so the field of view of the guide cam will be very narrow indeed. So the only answer would be to get a shorter FL telescope, or a guide cam with a larger sensor. Not wildly helpful, I know!

[redfox1971]

I had the same problem with my Orion dulux off axis guider on my cpc800,with qhy5 camera,I managed to focus the moon but trying to find a star was a joke,also the locking ring for dslr did not tighten kept jumping the threads and 1 of the locking pins fell off in my hand,very poor quality! so guider is back in box in cupboard collecting dust,think i should have tryed the celestron version,I use the qhy5 on my 9x50 finderscope now find stars no problem,but get the dreaded image shift.

[JamesF]

I have to agree with Luke. The combination of a long focal length scope and a guide camera with a small sensor is going to make things difficult. It's probably not helped slightly by the fact that it's colour rather than mono. If you can't successfully find a guide star by rotating the OAG or its prism then I think you probably need to try a camera with a larger sensor.

James

[cosmicdonkey]

Thanks guys for your input. I was looking at the lodestar camera as I hear good things about them. It's just the whole focus thing that worrys me. The trouble is with the camera I am using at the moment is it needs to connect with a 1 1/4 nose piece there for not allowing me use of any of the extensions that come with it. I will keep on looking into it I guess. In the mean time if anyone is using the same scope as mine and are having luck with thier setup please let me know what you are using.

[cosmicdonkey]

Another quick question if I may I use a cgem mount. If I was to go for say an Orion st80 with qhy5 autoguider package would my mount be able to handle the extra weight. I also understand that mirror shift might become a problem. The whole idea of off axis guiders makes me want to run a mile at the moment. I see people using guide scopes on sct with good results are they limited to shorter exposure times because of the problems with mirror shift?