What's a top planetary imaging camera?

gregbradley · #1 13-02-2009, 04:51 PM

I am looking to branch into planetary imaging.

What is a top notch planetary imaging camera?

The one's I have checked out so far are the SKYnyx 2-1, Infinity 3-1,
Point Grey Research Grasshopper and Dragonfly Express.

I get the idea USB 2.0 is better than firewire with its requirement for an additonal card in your computer.

Any others?

Greg.

renormalised (Carl) · #2 13-02-2009, 06:59 PM

Imaging Source DMK21 or DBK21 are good...or the 31 model, if you want more pixels. A Mallincam Hyper + wouldn't be bad either. Even a GStar EX would make a good camera, especially the wireless version. You might even try a Meade DSI II or III. The ones you mention are very good as well.

AlexN · #3 13-02-2009, 07:17 PM

the imaging source cameras are good.. but given the choice, most of the top planetary imagers are using the Skynyx 2-1, I've seen many great images with the dragonfly express.. There is no doubt the DMK21 is great... the 31 model is not the best option.. I found out the hard way.. .its limited to 30fps... where as the DMK21 can do 60... very useful if you have enough aperture to feed it...

Renormalised : The mallincam/gstar/DSI cameras will work, but they are hardly optimal.. Each are good for what they are designed for, and can be used for planetary imaging.. however, as Greg mentioned, he's after a top planetary cam... The best way to go in this case, is to buy something specifically designed for the purpose..

I'd be going for the SKYnyx 2-1 myself.. I've not looked at the infinity 3-1... so it may be a goer too....

If I were you, I'd wait for the opinions from Paul Haese, Mike Salway and Anthony Weasly... They should know exactly what you should be looking for...

Cheers.
Alex.

renormalised (Carl) · #4 13-02-2009, 07:20 PM

Just prowling the net....come to think of it, you could even shell out for one of the smaller Starlight Xpress cameras, or an Atik camera.

renormalised (Carl) · #5 13-02-2009, 07:23 PM

Quote:

I'd be going for the SKYnyx 2-1 myself.. I've not looked at the infinity 3-1... so it may be a goer too....

They'd be my best bets too....I only mentioned the others as possible alternatives, if he was willing to branch out and maybe compromise a bit. I've seen some of the piccies taken with the Lumenera cameras, and they're fantastic. They'd be very hard to beat.

AlexN · #6 13-02-2009, 07:44 PM

why compromise when you're stickin the camera into a TEC 180mm fluorite triplet APO or a TAK BRC-250??

renormalised (Carl) · #7 13-02-2009, 09:20 PM

Money.....

gregbradley · #8 13-02-2009, 10:05 PM

This one seems interesting. Anyone know of any examples of images from these;

Point Grey Research
Grasshopper

http://www.ptgrey.com/products/grasshopper/index.asp

Also SKYnyx 2-1 are larger chipped cameras. Are the larger chips better or worse? Or is it all about the frame rate, noise levels and speed of download?

Greg.

renormalised (Carl) · #9 13-02-2009, 10:23 PM

No, don't know of any images taken with these. Looks interesting. Usually the faster the frame rate, the less atm' distortion will affect your images. Also means you'll have lower noise levels in the image (all things considering....i.e. chip performance) and the faster your system can pull images off the camera, the better. Larger chips mean better resolution, however you may have to compromise on the fps (frames per second) capability of your camera. Means more chance for noise from atm' distortions to creep in. Also longer download times for each pic (larger file sizes).

renormalised (Carl) · #10 13-02-2009, 10:33 PM

Just had a look at the brochure...the Grasshopper that's similar to a DMK/DBK21 has a frame rate of 200fps!!!!!. Now, that's fast!!!. Much faster than the Imaging Source cameras and I would imagine that the images captured should be rock-steady under most conditions.

AlexN · #11 13-02-2009, 10:40 PM

you'd never be able to feed it enough light to use 200fps... its a great idea.. but unless you're planetary imaging with a 0.5M scope minimum, you're not going to use 200FPS..

I dont know of anyone able to use 60fps... (might be some, but i've not heard of them)

renormalised (Carl) · #12 13-02-2009, 10:50 PM

Quote:

Originally Posted by AlexN

you'd never be able to feed it enough light to use 200fps... its a great idea.. but unless you're planetary imaging with a 0.5M scope minimum, you're not going to use 200FPS..

I dont know of anyone able to use 60fps... (might be some, but i've not heard of them)

I know....it's an amazingly fast capture rate. Too fast for most scopes....you need a light bucket and a half to suck in enough photons just to keep the chip illuminated!!!. Anyway, who knows...Greg may just shell out the money for a 40" OGS RC!!!!...problem solved

That's why on most scopes 30fps, or thereabouts, is more than good enough. Once you get to the 10-12" mark (and a reasonably fast F ratio) you maybe stretching it, but for anything smaller it's OK.

Good thing, though, is the camera would have controls on the fps rate anyway, so you could buy it and know it's going to be useful. Unless you went for a larger chip and didn't mind the slower fps.

AlexN · #13 13-02-2009, 11:01 PM

Quote:

Originally Posted by renormalised

I know....it's an amazingly fast capture rate. Too fast for most scopes....you need a light bucket and a half to suck in enough photons just to keep the chip illuminated!!!. Anyway, who knows...Greg may just shell out the money for a 40" OGS RC!!!!...problem solved

That's why on most scopes 30fps, or thereabouts, is more than good enough. Once you get to the 10-12" mark (and a reasonably fast F ratio) you maybe stretching it, but for anything smaller it's OK.

Good thing, though, is the camera would have controls on the fps rate anyway, so you could buy it and know it's going to be useful. Unless you went for a larger chip and didn't mind the slower fps.

Yeah I went the DBK31 which is capped at 30FPS, I've not used to image Jupiter yet with the C11, so I dont know if I'll need more than 30FPS or not... Theres no such thing as a fast F ratio for planetary imaging.. with my 8" F/6 Newt I would image jupiter at F/35, with the C11 F/25~F/35 is on the cards... I know this year with Saturn im only capable of about 8~10fps due to its low brightness... Will have to see whats possible when jupiter comes back into the sky...

renormalised (Carl) · #14 13-02-2009, 11:11 PM

I should think that the C11 will be OK, so long as you don't try and image at anything less than its native speed. Even then, you may need more speed on the camera than 30fps. At the speeds you're imaging at, I don't think there'll be a problem.

gregbradley · #15 14-02-2009, 10:36 AM

Good points. I have done some planetary imaging with a ToUcam but it was a while ago. But I don't think I imaged at much faster than 10 or 15fps.

The 180mm refractor won't have the light grasp of a C11 but it may work well in less than perfect seeing - not sure. Visually the advantage of a refractor is higher contrast and ability to cut through poorer seeing. But planetary imaging may require aperture more than anything.

The best visual image I have seen of Saturn was through my C11. I got some super seeing once early in the morning at my dark site when Jupiter was rising again (Aug?). Looking through a Tak FS152 and a TMB planetary eyepiece it was very steady and sharp although image scale was a bit small.

It may be the formula is lowest read noise, greatest sensitivity, fastest download time (firewire or USB2.0), largest aperture with sharpish optics and then a site with good seeing. Then add good capture software.

Paul Haese and Damien Peach are using C14's. Paul's is cooled with 3 peltier coolers. RCOS scopes all have fans to get rid of the thermal boundary layer that sits on top of the mirror and affects performance with as little as 1C
temperature difference between the mirror and the air. Mirrors are usually pretty thick so temperature differences are almost always bound to be there to some degree.

Seems like these chips are good:

Kodak KAI0340 200 frames per second 640 x 480 (Point Grey Research Dragonfly Express (about US$400 or so)
Sony ICX424 648 x 488 9.9um pixels 60 frames per second (Point Grey Research Dragonfly 2 US$795 or so)
Sony ICX285 but its only 15 fps 1384 x 1036 (Point Grey Research Grasshopper US$2595 expensive for planetary)
Sony ICX274AL 1624 x 1224 30 frames per second also ICX445 is a good performer.

Lumenera uses ICX205 1392 x 1040 in SKYnyx 2-1 (only 15 fps though although you can speed it up by using a smaller part of the chip - called region of interest (ROI).
SKYnyx 2-0 is the ICX424 chip and 60fps
SKYnyx 2-2 ICX274 1616 x 1232 but again 15 fps.

So if you have a large aperture scope you'd probably go for the one with the fastest frame rate all things being equal.
If you have poorish seeing your best bet would be large aperture and fastest frame rate with low noise as above.
If you have good seeing and moderate aperture (my situation) then large pixels and moderate frame rate with high sensitivity and low noise may be the go.

That would be the KAI0340 or the ICX424 with 9.9um pixels. Larger pixels usually means lower noise and higher sensitivity. Not sure if the extra megapixels affects the image that greatly as they are usually pretty small images.

What do you think?

Greg.

renormalised (Carl) · #16 14-02-2009, 12:05 PM

The Tak is a faster scope than the C11....greater FoV, therefore smaller image scale for things like planets, pn's etc.

As far as firewire vs USB goes, firewire is nearly twice as fast but you may not have a firewire connection on your computer. I'm lucky with my Mac, as they come with firewire sockets. Some of the dearer pc's will have firewire, but you may have to get a card and plug it into your pc.

Your assumptions about scope/imager performance have been pretty much spot on there. Here's an article from Sky and Telescope that may help you with a decision. Id be inclined to go with the ICX424....it's not overly fast, although as we mentioned before, you probably won't use the full 60fps for most situations. The KAI0340 is insane....200fps would be unusable on anything under 0.5 metres as you just couldn't gather enough light to keep up with the chip. You'd have to dial it down considerably on a smaller scope. Mind you, your images would be guaranteed to be rock steady even under poor seeing conditions. But what would be the point in stacking 44 million images gathered by a 180 or 250mm scope just to be able to see the pic!!!. That's why you need the lightbucket. The 648 x 488 pic size will give you a good image with the ICX424. Look at Mikes pics....his DMK21 is only a 640 x 480 camera and he gets great piccies. However, although his camera does 60fps, he probably only images at 25-40fps on good nights with bright targets. Dimmer targets would necessitate slower frame rates in order to image the target.

gregbradley · #17 14-02-2009, 07:52 PM

Thanks for that.

I was planning on increasing the focal length of both scopes with a Baader fluorite flatfield converter.

I think the Point Grey Research Grasshopper camera is the go.

As far as the camera goes I am leaning towards a Sony ICX 1.4mp 30 fps chip with firewire and get a firewire card for my computer.

It could also double as an autoguider.

Greg.

Paul Haese · #18 15-02-2009, 06:44 PM

Greg,

You know what I think already, but for everyone's benefit here. Here is what I think.

I really like the Lumenera skynyx 2-0. Low noise, fast, good well depth but I as Anthony; am always looking for the next camera that is better than the one I have at present.

My next camera is likely to have a slightly fast download rate, great well depth and it will have cooling. I may have to mod the camera myself for this last function. Manufacturers don't think it is necessary, but I beg to differ.

Generally, I have to say I am really happy with the camera I have now. And I suspect it will be some time before my dream camera eventuates. Like others have said or hinted at, camera's that can do 60 frames a second of more (like in vast numbers) require very large apertures to fully expose the histogram. You can under expose a little but it take quite a bit of skill to make your images look like planets instead of round circles with colour on them. So in general a scope of 13 to 14 inches can get around 40 odd frames a second fully exposed at very high resolutions. If you use smaller resolutions you can go faster but it sort of defeats the purpose really.

Anyway, this is just my opinion. I hope this helps.

netwolf · #19 15-02-2009, 10:30 PM

I have the Dragonfly camera, it is a great camera that can do really high frame rates. I am well pleased with the results with it so far. The expert on all things PointGrey is Anthony (bird), as he has tested various cameras from Point Grey and has produced brilliant results.
Another feature these cameras offer is ROI (Region of Interest), which allows you to select a portion of the frame and only capture that, this helps reduce bandwidth needs and file size.

Higher resolution is not necessarly a better thing for planetary imaging. From what I have read higher resolution (if it means smaller pixels) is only really of benfit for Lunar and Solar imaging work. If ofcourse the pixel sizes are the same and you have ROI capability then you could pottentially increase frame rate capture and use a smaller region for Planet work.

iceman (Mike) · #20 16-02-2009, 04:50 AM

At the moment, there's really only two cameras I'd look at changing from my DMK21AU04 to:

- Lumenera Skynyx 2-0
- Point Grey Research Grasshopper

Last time I spoke with Anthony about this, he put me onto the grasshopper as he said he'll be upgrading to this camera shortly.

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

The leftmost one, GRAS-03K2M/C.

You're also right, that any of these cameras will be suitable as an autoguider.

For planetary, you really don't want any more than 640x480 because you want the fast framerate. What focal length will you be imaging at?

Even Jupiter at opposition fits in the 640x480 px field of view at about 13-14mm focal length, and that's with the smaller pixel size of the DMK. With the lumemera and pt grey cameras, their pixel size is a bit bigger (7.4 microns) so the image scale is a bit smaller.

Don't forget the filter wheel and filters, too. What filters will you get?