What am I doing wrong?

[Martin 2]

The image of M42 I posted is the only one that was ok from about 30 subs, the rest were carp.

I'm using a hartman mask to focus, remote cord to control the camera, using the hat trick to avoid shutter vibration, but still getting bad stars on most of the subs but not all. Took a shot of a few clusters as well and some came out ok, others very poor. I know trying to get deep sky on a coolpix is asking a lot, but so much difference between subs is odd, in dss the star count is high on some subs and very low on others, any thoughts anyone.

M2

[Kaptain Klevtsov]

Could the 'scope have been buffeted by wind? That would make the stars go nasty. Or dew on something?

Captain Chaos

[Martin 2]

Thanks for the reply CC,

No it was a still night, after I took the M42 subs I took the cluster subs and one of them came out ok, I'm wondering if the scope is picking up vibration from somewhere.

M2

[CELESCOPE]

dont know where you are standing the scope , if its on a hard surface like concrete on a patio , i only have to tip toe around mine and even then keeping 6 feet away , it will show up on my subs , so if you are standing by it as you would be then keep really still dont cough sneeze whatever vibrations can travel a long way ,

Rog

[Kaptain Klevtsov]

Martin, can you post a bad frame, it might be evidence.

Captain Chaos

[Martin 2]

This is one of many carp subs, think Rog is right about the vibration, I did have it set up on a patio, I have vibbration pads fitted to the tripod but perhaps this is not sufficent.

M2

[MartinB]

Assuming you are using the NS8 in alt az Martin I would say that is vibration. The NS8 tracks very well in Alt az so it won't be tracking and it doesn't need to be polar aligned.

[Kaptain Klevtsov]

Well it's definitely movement of the 'scope and/or camera relative to the stars. Either vibration or a slipping clutch (I assume that the forky things have clutches?). Focus is OK, it's either something moving or something not moving (as in the tracking had stopped - low battery?)

Forgive my ignorance MB, how does it know how to track if you don't align it in any way? It could have been tracking round the wrong star if that is the case.

Captain Chaos

[moondog]

I reckon it's poor focus. Did you use a 2 hole Hartman mask ? Looks like it to me.

Sometimes if you focus on a distant street lamp or a bright star and swing to the object you want to image the camera mounting can move very slightly and cause the problem. I suffered from this last weekend when I was testing a new barlow on M42's Trapezium - if I didn't throw the image away I'll try to post it so you can see if they're similar.

MD

[Kaptain Klevtsov]

I disagree on the focus bit, but I might be wrong. What I can see is trailed stars which are in focus as there are linear features. Out of focus would be bigger than optimum round stars.

Captain Chaos

[Martin 2]

I cant get away from standing the scope on a patio so would placing the tripod onsome thick rubber matting help?

M2

I do use a hart man mask for focasing, and as I said before not all subs come out bad, so it is intermittent.

[MartinB]

Well it's definitely movement of the 'scope and/or camera relative to the stars. Either vibration or a slipping clutch (I assume that the forky things have clutches?). Focus is OK, it's either something moving or something not moving (as in the tracking had stopped - low battery?)

Forgive my ignorance MB, how does it know how to track if you don't align it in any way? It could have been tracking round the wrong star if that is the case.

Captain Chaos

NS8 GPS - just plonk it down any old how and run the star align routine. It knows where north is and cos its working in alt az it uses the star mapping from the alignment to keep everthing on track.

[CELESCOPE]

Martin its vibration, i used pads for along time , dont help mate , either u have to work away from the scope , or as i said stand really still hold ya breath ,

Rog