Astronomik clip filters for Narrowband

[AlistairW]

Hello,

I have a H-alpha and a OIII Astronomik clip filter on order. My question is that although these are parfocal, when I am imaging on a DSO and I change filter, I might get the orientation of the camera slightly out, or I might nudge the mount a bit whilst changing. All this will effect focus I guess. I presume this is all eliminated with a filter wheel assembly. Will I need to be careful changing the filter not to effect the overall assembly ? 

Thanks

Alistair.

[geordie85]

I find the easiest way to change clip filters is to unattach the camera asif you are changing lenses, by pressing the little button to release your t-ring. That way when you reattach the camera to your t-ring it's in the exact same orientation as it was before removing your camera

[Astrosurf]

I find the easiest way to change clip filters is to unattach the camera asif you are changing lenses, by pressing the little button to release your t-ring. That way when you reattach the camera to your t-ring it's in the exact same orientation as it was before removing your camera

Excellent idea!

Alistair, if I haven't got this wrong, your narrowband filters will only use one colour in the camera sensor's Bayer matrix. For example, the Ha will only use the red photosensors, so that's only a quarter of the matrix. Your image will be noisy and will need longer exposure times than for broadband imaging.  Or at least that's what I've experienced and what I've read! Do take darks to help remove the noise. I don't know what colour the OIII would use. Green?? If so, there are twice as many of those so that would be 50% of the photosensors.

Someone much more knowledgeable will be on here very soon!

Alexx