Deep NGC3199 Nebula in 3nm Ha, 28hrs.

[RickS (Rick)]

Clive,

Just add an EMCCD camera and voila... lucky imaging of DSOs in narrowband.

Cheers,
Rick.

[clive milne]

Yep, they're an interesting idea and key enabler for high frame rate astronomy of low surface brightness objects.

I still like the Kingfisher V with the icx 694 for deep exposures though.
The readout noise approaches emccd's, but for dark noise the sony chip is in a class of it's own. In the kingfisher, it equates to 1 electron per fortnight!

[RickS (Rick)]

Originally Posted by clive milne

I still like the Kingfisher V with the icx 694 for deep exposures though.
The readout noise approaches emccd's, but for dark noise the sony chip is in a class of it's own. In the kingfisher, it equates to 1 electron per fortnight!

That's very impressive. I wonder how long they take to cool down. Have you ever priced one?

[Mighty_oz (Marcus)]

Interesting discussion guys 😃
Clive would your system still be workable with a 25" F4.9 system ? Anything major u would have to do with it ? I've not heard any mention of a rotator for the newts, so the camera is video , yes ? ( pardon my ignorance, still learning like the rest, hehe )

[clive milne]

Marcus,
The system could be made to work with a 25" f4.9 Newtonian. The optical design is easy. The (mechanical) engineering challenges however, would not be trivial nor inexpensive.
The ccd that I would recommend is not what I would call a video camera as such, even though it can take video. There are budget options (for the camera) a second QHY22 will set you back $3k. The pick of them (Raptor Photonics) will be around the $10k mark.

[clive milne]

Rick,
I'm not sure about the cooling down time on the Kingfisher.
What I can tell you is that it requires 0.5L/min of cooling water, and the system needs to dump 100W of heat (about the same as a human body at idle)
As for frame grabbing software.. I don't know.
To my understanding, one of the professional observatories on the east coast has invested in one of these cameras so it is obviously possible.

best
c

[RickS (Rick)]

Something to think about if/when I have time to tinker in future, thanks Clive.

[clive milne]

Your welcome.

fwiw) I have been chewing on this idea a little more and come to the conclusion that inserting a Fabry Perot etalon into the collimated beam (between the relay lens pair) isn't really viable because the divergence tolerance is so small (equivalent to f30)
You can achieve a better s/nr by sticking to an ultra narrow band filter (1nm for example) The reason is that the interference filter gives you much greater flexibility with the choice of final focal ratio after the relay lenses with large apertures and enough fov to cover an icx694 chip.
At the end of the day the purpose of the exercise was to configure a system where shot noise was the limiting factor.

best
c