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View Full Version here: : QHY-11 with a fisheye lens


Tau_nuetrino
17-08-2011, 06:21 PM
Hi all,

My colleague has been using a SBIG all-sky 340 camera to take photos of the night sky to quantify light pollution around LNG sites in North-West W.A. The problem with this camera is that it doesnt cover the entire sky, which is probably because of the CCD chip (4.74mm X 3.55 mm) being smaller than the image circle for the lens. Now the job has been given to me and I have been thinking of using a camera with a bigger chip, such as either the QHY 9 or QHY 11. So my question is can I use either of the two cameras with any fish-eye lens or do I need to match certain specs of the lens and the camera?

Any help would be much appreciated.

Cheers,
Arwin

multiweb
17-08-2011, 06:26 PM
QHY9 sensor will be too small. QHY8 is bigger. I don't know sensor size for QHY11.

mithrandir
17-08-2011, 10:15 PM
The QHY11 is nominally full frame - 36x24mm with 9u pixels. Theo doesn't have a price listed.

What fisheye were you considering? For example the Tokina 11-16 zoom (not strictly a fisheye) would give you something in the ballpark of 180x120 degrees at 11mm and 120x80 deg at 16mm.

marki
17-08-2011, 10:46 PM
QHY11 costs $4400 from Theo. He has them in stock according to the website. The KAF1100 chip is much larger then the KAF8300 in the QHY9 (18 x 13.5mm Vs 36 x 24mm) and will get more sky in a single shot.

Cheers

Mark

Tau_nuetrino
18-08-2011, 02:22 PM
I already have this (FE185C046HA-1) fish eye lens which came with the SBIG all sky camera. I need something that can cover the entire sky.

The problem with the current setup can be seen in this video (https://www.youtube.com/watch?v=AYtVNoPW_-Y)

As you can see it attenuates a little bit of the sky at top and the bottom. This normally wouldn't an issue but I need to quantify light pollution for marine animal conservation studies. It so happens, in the last field runs, lights from offshore oil rigs would have been visible had that part of the image not been attenuated. At the moment I have to do 2 sets of runs from each location. Again this isn't too much of an issue but its kinda expensive for the company to send me to these remote sites for twice as long.

Also since the fish eye lens I have wont illuminate the whole of the QHY-11 chip, will that cause me problems?

All I will be doing is differential photometry, so will QHY-11 with a fish eye lens do the job? if not, can anyone recommend a better setup?

Thanks for the help so far guys, really appreciate it :)
-Tau