Off Axis Guiding and PHD Problems

[valleyman]

Just bought a Celestron OAG and GPUSB to run with PHD. I am using a DHK21 CCD as the guide camera. All mounted on a C11 and HQ6 mount.

This is the situation.

The DMK is working fine when attached to the C11 and get great videos of the moon etc. So no problem with the Camera.

When I attach it to the OAG and switch on PHD. Carry out the correct switching on sequance ie: select Camera, connect to Telescope, then switch on the LOOP switch. All I get displayed in the View is Noise. A lot of noise.

I have rotated the OAG to every position and also adjusted the Prism to every position. I have adjusted the Gain indicator on PHD to every position which only makes the noise lighter or darker.

If I disconnect the DMK and run the IC Capture for DMK the Camera is working fine. No Noise.

When It goes back onto the OAG just noise again.

Any help would be appreciated.

Pat

[Freddie]

With a DMK21 and OAG you get a tiny FOV. I have just moved to OAG on my MN190 and had a quick go with my DMK21 before I got my Lodestar. I think you will find you are just not picking up a star and thefore just seeing noise on screen. Have a go at pointing it at the moon and I think you will find everything is working fine but in a normal shot you are just not picking up a star. On my DMK, I was 3 sec and 1000 gain and usually had to hunt around to find a star.

[valleyman]

There is so much noise it would not be possible to see a star. Looking at the pics on the starklabe web page my screen looks nothing like theres.

I ran it all with the lens cover on the C11 it should have just been Black but still nothing but a mass off noise.

[Freddie]

Did it connect to the cam correctly? i.e. it did find the DMK to select? Have you checked the cam settings using the "cam dialog" icon in PHD?

[dmahon]

If all you have is noise, how do you know you have focused?

[valleyman]

I was out last night and had my Canon 600d attached to the OAG focused and centered on Arcturus. I know that the DMK is a fraction of focus with the OAG and I am waiting for some spacers from Opticstar to move the Canon a bit further back to give me some movement for focusing the DMK. But all I had on the PHD screen was a mass of Noise

[valleyman]

Just had it set up in daylight, turned the exposer right down connected it all up, focused the DLR on some trees about a mile away and with the C11 front covered by about 85% to reduce the light coming in, can just make out some movement from the trees. There was no noise.

[r3i]

Can you try it on a bright star like Arcturus by first getting the star in the FOV of your Canon then, assuming your guide camera is vertically above your Canon, progressively nudge the position of the mount so that the star moves off the FOV of the Canon and eventually onto the FOV of the guide camera. A Bahtinov mask will also help with this as you should be able to see the rays start to appear in the guide camera's FOV before the star. I found this technique handy when I was fine tuning the sync'ing of the focussing between the 2 cameras.

[valleyman]

thanks for all the replys, just waiting for a clear night now to try thr suggestions