External shutters?

[coatesg]

Bit of kit thinking here - CMOS cameras don't tend to have shutters in the way that many CCD based cameras do. 

Has anyone ever seen an external shutter that can be placed in the imaging train? (I'm thinking about ease of dark frame capture here - something with some kind of large thread like an M68 or whatever to screw in place in front of the filter wheel?

Cheers

[vlaiv]

Not really seeing the point?

You are clearly not talking about actual shutter action, are you? Such a large device will have great inertia and slow shutting times. If you want to make just a light blocking device that you would use instead of scope cover to use when taking darks, how about once place in filter wheel with "dark" filter? Just take a piece of plastic or maybe even metal (or plastic covered with aluminum foil on side facing scope) and put that in one filter place?

[coatesg]

30 minutes ago, vlaiv said:

Not really seeing the point?

You are clearly not talking about actual shutter action, are you? Such a large device will have great inertia and slow shutting times. If you want to make just a light blocking device that you would use instead of scope cover to use when taking darks, how about once place in filter wheel with "dark" filter? Just take a piece of plastic or maybe even metal (or plastic covered with aluminum foil on side facing scope) and put that in one filter place?

Yes - of course that works - though I'm thinking about the ability to schedule/work remotely without having to physically go and stick the lens cap on. My initial thoughts were whether something like an Alnitak flip flat would offer enough "light tightness" to work in this regard?

I'm not sure a filter wheel would offer enough protection against light leaks around the outside of the filters (and not enough spaces in the wheel!)

 

[Dr_Ju_ju]

So from what I can gather, you're after some sort of remote controlled lens cap ??  If so, there are a number of designs, based on Arduino control with 3D printed parts, in the "DIY Astronomer" section, or even other sites like thingiverse.com

[hughgilhespie]

If you have a spare position on your filter wheel you can block it with something opaque to make a sort of shutter. I have done this with my ZWO 8 position filter wheel. I machined a bit of black Delrin plastic rod to fit in the 31 mm opening with a thin flange to stop it falling through, then secured it using the little screws that come with the filter wheel. When it's in place, it does completely block out all the light from the telescope side.

Regards, Hugh