What's a top planetary imaging camera?

[bird (Anthony Wesley)]

Greg,

I own a few of the current crop of cameras:

Lumenera LU075M
PGR Dragonfly Express
PGR Dragonfly2
DMK21AF04.AS

Comparing firewire and USB cameras is a tricky subject, you have to be careful that you really understand the differences. Firewire cameras are cross-platform and will run when connected to Windows, Linux or Mac, normally with any firewire video program because the video is part of the firewire specification.

USB cameras require a specific driver wherever you want to use it because there is no usb video spec and so every camera does it differently. eg if you have a camera with a Windows driver then it probably won't work anywhere else, and you'll be relying on the vendor to keep releasing new drivers for new versions of windows.

Because I use Linux for my video capture and scope control I have no real choice but to use firewire. I have one generic video capture program called coriander that understands all my firewire cameras, with no vendor-specific driver needed.

Firewire also has a lower cpu usage since the firewire driver chip can transfer the video itself, whereas usb needs the cpu to assist in receiving and saving the images.

My current favourite cameras are the PGR Dragonfly2 and Dragonfly Express, but I'll be upgrading to this camera as soon as it's available:

http://www.ptgrey.com/products/grass..._datasheet.pdf

The specs on this camera are wonderful, and the new kodak ccd's are very low noise. The 14 bit ccd will be an improvement over my current 12 bit ccd in the Dragonfly2.

The only downside to firewire cameras is if you're using Windows - I'm not sure there's a good firewire capture program out there for Windows users - maybe there is, if anyone knows of one they can post about it? Under Linux there's coriander which is one of the best capture apps anywhere.

PGR are also releasing a new software dev kit (SDK) which will be cross-platform, so capture apps written for Linux will run on Windows and vice versa. When I get my hands on that I may start writing or porting my linux app over to Windows, but there's no word on when this will be released.

cheers, Bird

[bird (Anthony Wesley)]

ps, a comment about frame rates...

For the outer planets (Mars, Jupiter, Saturn) you have to complete the imaging run in a relatively short time, on Mars you have about 5 minutes and the other two somewhere between 2 and 3 minutes max. To get the most number of usable frames means using a short shutter, but you don't want to be wasting any light - ie throwing away or not capturing light during the run - so you'd ideally use a framerate between the camera and the pc that's i/e where e is the exposure.

eg if you're capturing at 40fps then you'd set the exposure to 1/40s. This way all the light that your camera captures during the imaging run is sent to the computer.

The exception to this rule is lunar imaging, I routinely use exposures of 1/1000 second because it's so bright.

The best exposure setting will depend on the scope and camera, so you'd ideally want a camera that lets you set the fps to any value that's reasonable, and automatically have the exposure set to 1/fps.

I value a high fps over almost anything else - to the point that I set my exposure short enough to only about half-fill the histogram. This loses me 1 bit of resolution, but gains me 2x the number of frames (which can give me most of that 1 bit back again anyway).

For this to work you need a camera that can do a user-defined fps, with exposure set to 1/fps. Not all cameras can do this - it requires them to overlap transmission of the last completed frame with the exposure of the next frame. This is surprisingly difficult for cameras to do - sending a frame draws more current and the a/d stage can see a drop in its reference voltage which shows up as a dark or light patch on the next image (one of my old cameras did this, but all the PGR cameras are ok).

cheers, Bird

[netwolf]

As to the software Bird is right Windows support is not as great. For Window you have two types of Drivers a DirectX/VFW driver, which then allows you to use any capture software (but is very buggy). Or a DCAM driver that limits you to software that supports this type of driver, the default FlyCapture software from Pointgrey or others such as MATLAB Image Processing and Aquisition Toolkit, Unibrain FireAPI, ubCore, Fire-i API, Norpix Streampix etc. All are quiet expensive.

A MAC Option is Astro IIDC, which froomt he looks of it is quiet good. I have tried to get developers of Lucam recorder and other capture software to provide support for these camera's but as yet nothging has come of it. Stuck with using the Flycapture SDK.


Regards
Fahim

[gregbradley]

Hi Bird,

Thanks for the very informative reply.

I also am interested primarily in the Grasshopper 2. I asked PGR about this and was told it is still early in development and they will contact me when it is released.

In the meantime I am looking at a PGR Grasshopper.

As you know there are several chips you can order.

The KAI0340 does 200fps and 640 x 480.

Then there is another Sony that is 648 x 488 and 74 fps. You can also get the ICX285 chip but that camera is US$2595.00 plus it only does 15fps or less. Which seemed to me to be too slow. I know this is the chip you recommended on an earlier post on the Astromart Solar System forum this time last year.

I was thinking of the ICX274 model which is 2mb and 30fps. The number of fps can be increased by ROI. So I thought that would be handy when I want faster frames but the extra resolution of the 2mp chip could be handy at times.

Is this correct thinking or is 640 x 480 adequate and trying to go for 2mp not worth it?

I see that is the same chip as the Lumenera 2-2 but the Lumenera only does 12fps.

Also the PGR states output can be 8,12,16 or 24 bit.

Am I reading that right that you can output it at 16 bit same as a deep space CCD camera?

Or is 2mp at 30fps and 16bit impractical and limited by download speeds and ability of the hard drive to save that much data that quickly?

Also can I ask what is a likely number of fps I would be able to achieve in your estimation using either a Tak BRC250 or a TEC180mm fluorite APO?
That is relevant as it is a waste to worry about high fps if those rigs won't give enough light on the main planets to give a bright enough image.

Greg.

[gregbradley]

Thanks Fahim,

If I read your post correctly does that mean if I get a PGR camera Lucam recorder won't work with it?

I currently own K3CCD tools. Will that work with it or is the camera limited to PGR software. I haven't priced their capture software yet.

Best,

Greg.

[netwolf]

Greg, at present Lucam Recorder does not suport the PGR Camera specifically. The author advised me that he would look at it after DMK Camera integration was completed, but since then he has not replied to my emails. K3CCD might work with the DirectX/VFW Drivers for PGR. My experience was with Astrosnap and the VFW Driver, but the integration was not smooth. However the VFW Driver has matured since then so might be better now. For all the pains of it it is still a camera I would reccomend. Skynyx is also an excellent camera but I do recall the software for that is also quiet expensive. Greg if you would like I can possibly loan you the Dragonfly to try out. It has been sitting packed up for long enough some one might as well use it.

Regards
Fahim

[Paul Haese]

Fahim, the skynyx camera works with Lucam Recorder. It is only about $120 for the license. I have been using this and it works fine. Only flaw is that the frame rates for Jupiter are only about 30fps. I did get frame rates on Mars about 57fps. Not sure why this occurs, but Lucam Recorder also allows for filter imaging runs. I just set all the values and click record and it starts the run and when it finishes recording the last colour it returns the filters back to the start point. Very automated and nicely written.

[bird (Anthony Wesley)]

Originally Posted by gregbradley

Hi Bird,

Thanks for the very informative reply.

I also am interested primarily in the Grasshopper 2. I asked PGR about this and was told it is still early in development and they will contact me when it is released.

In the meantime I am looking at a PGR Grasshopper.

As you know there are several chips you can order.

The KAI0340 does 200fps and 640 x 480.

Then there is another Sony that is 648 x 488 and 74 fps. You can also get the ICX285 chip but that camera is US$2595.00 plus it only does 15fps or less. Which seemed to me to be too slow. I know this is the chip you recommended on an earlier post on the Astromart Solar System forum this time last year.

I was thinking of the ICX274 model which is 2mb and 30fps. The number of fps can be increased by ROI. So I thought that would be handy when I want faster frames but the extra resolution of the 2mp chip could be handy at times.

The ICX274 is a very popular ccd - it's used in some of the SkyNyx cameras, the PGR Dragonfly2 and a few others.

Is this correct thinking or is 640 x 480 adequate and trying to go for 2mp not worth it?

640x480 is enough for most purposes. You end up adjusting the focal length of your scope with barlows to use this resolution properly, so you're not losing anything. This is enough resolution to have several pixels cover the theoretical airy disc.

Also, the 2MP cameras invariably have small pixels which capture less light, so in the end you'll end up reducing the focal length to bring the image back to about the same size on screen as the 640x480 camera anyway.

I see that is the same chip as the Lumenera 2-2 but the Lumenera only does 12fps.

Also the PGR states output can be 8,12,16 or 24 bit.

Am I reading that right that you can output it at 16 bit same as a deep space CCD camera?

Or is 2mp at 30fps and 16bit impractical and limited by download speeds and ability of the hard drive to save that much data that quickly?

Also can I ask what is a likely number of fps I would be able to achieve in your estimation using either a Tak BRC250 or a TEC180mm fluorite APO?
That is relevant as it is a waste to worry about high fps if those rigs won't give enough light on the main planets to give a bright enough image.

Greg.

This is a difficult question to answer, as there are two variables - the image size (focal length) and the camera fps. You need a compromise where the image size is large enough to see what you're after, and also the camera fps is high enough to get the best quality result you can get.

Maybe we can work it out by comparing focal ratio - that keeps the image brightness constant but allows the image to get larger or smaller as needed.
With my current camera I'm using around f/40 on Jupiter and Saturn, with the camera set for 40fps on Jupiter and 25fps on Saturn.

If we keep the f/r the same, then you can work out the focal length on your scope (sorry, I don't know the native focal length of these scopes but I guess you do...).

I'd guess that the focal length will be relatively modest, and so the image size will be small, but there's not much more you can do without more aperture.

You can compromise by lowering the camera fps and this would allow you to increase the focal length and image size. The best combination will depend on your seeing conditions.

cheers, Bird

[netwolf]

Paul, my mistake that is correct Lucam will work with the Skynyx and the older lumnera camera's. But I also recall reading that the software SKynyx sold was quiet expensive. However Lucam is specifically designed for Planet imaging so its better for this purpose than the default ones. This is what I like about Lucam and the one provdied with the DMK and DBK Cameras.
For PGR Cameras the best choice is perhaps K3CCD and using the VFW Drivers for the PGR Camera. The SDK demo software works well enough for cpaturing but has not Histrogram feature. However the SDK Software does capture to RAM And then writes to disk which is a nice feature.

[gregbradley]

Thanks for the replies guys. This is golden information.

Both the TEC180 and the BRC250 are 1260mm focal length. I am planning to get a Baader flourite flatfield converter from Astrophysics that does up to 8X with a 50mm corrected circle.

I have seen some nice Jupiter shots from a TEC200 fluorite so I am hoping its enough aperture to capture some decent images. If not I may pick up a C11 or something similar. I have a large PEC cooling unit with a radiator unit as well that could be used to either cool the scope or the camera.

PGR also emailed me and suggested the Flea 2 with the ICX445 sensor which seems quite sensitive.

What is your current camera Bird - the Dragonfly Express? Which chip is that one?


Greg.

[bird (Anthony Wesley)]

Greg, I have 2 PGR cameras, the Dragonfly Express with a Kodak KAI-0340DM, and a PGR Dragonfly2 with the sony ICX424AL. They are both very good cameras, the Kodak has more blue sensitivity than the sony, but the sony has a bit less noise. It's hard to pick a clean winner.

The Dragonfly Express has S800 firewire output and can do up to 200fps, this is very useful for lunar work but I don't have a big enough mirror for this to be needed on other planets.

I'll be upgrading to the PGR Grasshopper2 (1600x1200) as soon as I can buy/steal one :-) They look like great cameras, low noise and 2xS800 data outputs, ie 160MBytes/sec between camera and computer. I guess I'll need to upgrade my computer as well :-)

cheers, Bird

[netwolf]

Bird what is the pixel size on the G2 1600x1200?

Regards
Fahim

[bird (Anthony Wesley)]

Fahim, According to the datasheet:

http://www.kodak.com/global/plugins/...50LongSpec.pdf

it's 5.5 microns, very close to the ICX098 used in the ToUcam and DMK21AF04 cameras.

However it has a quad-port readout, so the ccd is read out in 4 parallel channels, making it very fast to read out the data. This has been the main limitation of large format ccds for planetary work in the past - they were too slow.

The KAI-0340DM in the Dragonfly Express is a dual-port ccd, so I guess this is the next logical step.

In quad-port mode the KAI-02050 ccd can hit 68fps for full-frame data (1600x1200). Not too bad.

cheers, Bird

[gregbradley]

Thanks for the info Bird.

I was wondering about this quad output. Will it require a special card to handle it or will it be a standard cable?

Greg.

Originally Posted by bird

Greg, I have 2 PGR cameras, the Dragonfly Express with a Kodak KAI-0340DM, and a PGR Dragonfly2 with the sony ICX424AL. They are both very good cameras, the Kodak has more blue sensitivity than the sony, but the sony has a bit less noise. It's hard to pick a clean winner.

The Dragonfly Express has S800 firewire output and can do up to 200fps, this is very useful for lunar work but I don't have a big enough mirror for this to be needed on other planets.

I'll be upgrading to the PGR Grasshopper2 (1600x1200) as soon as I can buy/steal one :-) They look like great cameras, low noise and 2xS800 data outputs, ie 160MBytes/sec between camera and computer. I guess I'll need to upgrade my computer as well :-)

cheers, Bird

[bird (Anthony Wesley)]

Greg, the quad output is handled internally in the camera, kinda like the dual outputs on my current camera.

BUT if you want to reach the maximum speed then you have to use both the S800 firewire outputs on the camera, and this will require some special-purpose program (or maybe just two separate programs both running at the same time, each capturing half the frames).

PGR are releasing a development kit to allow this to be merged into existing programs, I'm hoping to get a look at the SDK fairly soon.

cheers, Bird

[gregbradley]

Thanks.

I hope they make it a seamless experience as if its too complex or if they leave the customer to sort out the hardware issues it wouldn't be too attractive to me.

Greg.