Is this any indication of collimation?

[Keithp]

Hello All,

Out all night waiting for Jupiter to arise, which it did, image in the planetary section. Just a quick question regarding collimation. Does the star image below showing the four spikes, I assume caused by the spider, indicate good collimation in any way? Don't know what the artifact is that also appears.

Regards

All

Keithp

[barkis]

They would not be that good if your mirrors were out of alignment.

How did you take the picture. Did you hold a camera lens to the eyepiece perhaps.?

Ron.

[Keithp]

Hi Ron,

I've an adapter to t peice on the camera that clamps on to any eyepeice with removable rubber shields. It has three nylon screws that locate in the groove allowing adjustment to centre the camera on the eyepeice. I took the picture while waiting for Jupiter to come up so did a little more collimation. Amazing at about 3 in the morning, once my eyes had adjusted.

[Tim]

Keith, the sharper and tighter those spikes appear, the better your Focus, I dont think you can guage too much from the spikes about collimation. By defocussing slightly and taking a pic you will get a donut shape, and in the centre of the screen the centre of the donut should be central to the shape, not offset to any one side.

[barkis]

That looks like an afocal image. Does your adaptor attach to the filter threads of your camera lens Keith.? Not that it makes a lot of difference, but that artifact looks like a lens reflection.

Ron.

[Keithp]

Hi Ron,

Yes it is an afocal shot, but not had that on any other images I've taken. Maybe it was just a one off.

[Milamber]

Yup - reflection, the camera need only be a gnat's off parallel and with a target that bright you're going to get one.

Arthur