From: Stephen Ramsden <sramsden@natca.net>
Date: May 23, 2015 4:11:32 PM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] IR Cut Filter Necessary?
Kevin,
I hate to even break in here but in case you didnt know…
I run a forum at http://solarchat.natca.net where we have about 20-25 people currently using the USB3 grasshoppers for solar imaging. They are all PC users as I am the only Mac user on there I think, but some of them may have tried it on a Mac. I have heard no one find anything that could run these cameras in native Mac. Unfortunately.
Milton’s absence has set back solar astronomy years and has virtually eliminated the chance of getting most people under 40 interested in it…(as they all use Macs)
Stephen W. Ramsden
Nonprofit 501c3 Director
Atlanta, GA - United States of America
404-543-7616
On May 23, 2015, at 5:30 PM, Kevin in Fort Davis fsm79734@gmail.com [Astro_IIDC] <Astro_IIDC@yahoogroups.com> wrote:
Thanks for those great suggestions, Milton. The FW800 hub I'm currently using is this one:
http://www.amazon.com/NitroAV-8-Port-FireWire-Professional-Repeater/dp/B00506K4NC
and its power supply is rated at 12V/3A. When I first started having the FW bandwidth issue (everything worked fine for nearly two years before this problem developed), I tried swapping in the exact Kramer hub that you mentioned, with the same result. I've also replaced all the cabling end to end.
I have not tried running the cameras at 1624x1224 8bit. Will the image quality not suffer at 8 bit? I will try that as soon as it stops pouring rain.
I will ask PGR if their USB3 cameras can run at USB2 speeds and what the minimum frame rate is. Unless I've missed it, they only specify a "frame rate" which is presumably the fastest frame rate.
-Kevin
On Fri, May 22, 2015 at 8:58 PM, Milton Aupperle maupperl@gmail.com [Astro_IIDC] <Astro_IIDC@yahoogroups.com> wrote:
Hi Kevin;
On 2015-05-22, at 11:46 AM, Kevin in Fort Davis fsm79734@gmail.com [Astro_IIDC] <Astro_IIDC@yahoogroups.com> wrote:
Milton, I probably should have included more detailed information as to why I'm considering PGR USB3 cameras. It's not for USB3 frame rate, but rather to get the to PGR cameras with larger physical chip sizes. We need the image coming from the Lunt telescope to be full-disk, and it's not quite full-disk with the PGR USB2 Chameleon and Firefly 1/3" CCD cameras. We need the chip size to be closer to 1/2". We have two PGR FW800 2MP Flea3 cameras with which we've been quite happy, and we use those to show white light and hi-mag H-alpha views of the Sun. However, because of the physical setup in the dome, our cable lengths are pretty long (4.5m from cameras to FW800 hub, then another meter to the computer), so it's sometimes a challenge for both cameras to be recognized at the same time - presumably because of the long cables. Thus, I'm afraid of adding yet another FW800 camera and long cable on the same bus. We could restructure the physical layout of the electronics in the dome, but with long focus 6" and 4" refractors, the cables by necessity have to be pretty long to allow for all slewing angles.
A couple of things you can try.
1) Is the FW Hub powered or not? And if not, have you tried powering it? Some hubs do not pass through full amperage and in edge cases you could wind up with the cameras just barely working - which would make it flakey. Also check to see what the voltage and wattage the power adapter delivers is adequate for those FW Cameras (it should be 12 volts and at least 2.5 watts per camera, so around 0.5 to 1.0 amp will be fine for 2 cameras).
2) The maximum a FW 800 Cable should be is 4.5 meter when running at 800 mbps. Unless the FW Hub has repeater properties (basically amplifying the signal), the drop in signal could be part of the problem. Something like this:
might solve that issue. That would also give you a little more freedom in configuration too, as you could go to 4.5 meters from camera to the Hub and 4.5 meters from the hub to the computer too.
3) Have you checked that your cables are good? A bad cable with an intermittent short can cause all sorts of weird issues.
4) If your running the 1624 x 1224 FW 800 cameras at 7.5 fps in 8 bit, you should be able to run three or four of them off the same bus without any problem. If you got to 15 fps or 16 bit per pixel, you will only be able to run 2, there won't be enough bandwidth.
As far as cameras go, I would stick with USB 2 or FireWire 800. The issue with is USB3 is that the camera may not run because it has minimum frame rate speeds and might not be able to transfer frames fast enough over USB2. PGR would have a better idea as to if their USB 3 cameras will run at USB 2 speeds or not.
HTH..
Milton Aupperle