Which entry level CCD imaging for planetary photo?

[EricB]

Hi everyone!

I have recently got myself a SkyWatcher 10" GOT dobs. While I need to familiarise myself with the scope first, I am thinking that in a few months, I would like to have a go at lunar and planetary photography (as I understand that dobs can't really do DSO photography).

I have been considering various CCD imaging cameras at the cheaper end of the scale:

- Andrews comm. planetary and lunar camera ($119 - Andrews)
- ProStar - Planet-Cam ($129 - My Astroshop)
- Meade Lunar and planetary imaging ($? only seen on a US site for $99)
- Celestron nextimage ($299 - Ozscopes)
- Imaging Source DBK 21AU04.AS ($379 - Bintel)

Has anyone have used any of these?

Andrews claim that their camera is as good as Nextstar (and is made at the same factory). They they told me that it has a compatibility problem with vista and windows 7.

I have read good reviews about the Meade LPI but again there seems to be a compability issue with windows 7 (has it been resolved?). I haven't been able to find it on Australian websites. Is it available and at what price?

The Imaging Source one has good reviews as well, but is more expensive.

Thanks in advance for your advice.

Cheers,

Eric

[mswhin63]

Planetary imaging is all about High Frame Rat and High resolution along with CCD sensor not CMOS.

It would be hard for any one individual to accurately report on all of these as they would have only use one maybe 2 units. Personally reviews are good to find faults.

The best method is to find the a good starting point is look at the highest Framerate (FPS) and the check other cameras to see if the framerate is the same at higher resolutions eg: CAMERA 1 - 30FPS 640 x 480, CAMERA 2 - 30FPS @ 1280 x 960. Although highly unlikely CAMERA 2 is better but more realistically you may want to look at mid framerate for comparision eg 15 fps or less. It is a long drawn out process but if you see something with the same spec then I would go for the cheapest.

Resolution provides more detail while framerate assist in image processing for poor seeing conditions.

After all that crud, reviews for the Imaging Source cameras have been the most positive but they do have a much higher marketing profile compared to others. I think there is a FLEA or FLI planetary camera as well with good reviews.

[mswhin63]

FYI couldn't locate the Andrews camera.

Had a look at Prostar and has typical marketing shows ONLY the highest resolution and the highest frame-rate but used you deceitful words "UP TO"

[Screwdriverone]

Hey Eric,

In my opinion, go for the DBK, its the camera I have my eye on getting when I have the funds for three reasons:

1) Lots of images I have seen with this camera are excellent, especially planetary images using a barlow and it seems the noise level is quite low.
2) It can also be used for deep sky as well (limited with a dob because of field rotation) but can go as long as 60 minutes per exposure.
3) Relatively cheap for a dual purpose camera, as you progress and probably get into AP later on, this camera makes an excellent guide camera/planetary camera later on when you need a guide scope connected to an EQ mount for long exposure AP.

Ps....keep it quiet...there are TWO on Ice trades at the moment, one mono for $275 and one colour for $250.....just wish I had the cash to buy the colour one myself.....damn it......keep in mind that the mono one will need a filter wheel and filters to make colour images, so go the colour one if you want a bargain.....$129 off is a good saving!

Cheers

Chris

[EricB]

Thanks Malcolm and Chris.

The Imaging Source DBK 21AU04.AS could be the way to go, especially if I get a dedicated scope down the track.

However, having just bought the scope I can't really afford to buy the camera right now, new or second hand. Furthermore, I feel I need to get a good grip on the scope and on basic visual astronomy before I can have a go at astrophotography.

I can see right now that this is going to be a very expensive hobby...

Cheers,

Eric

PS Malcolm, the Andrews camara is available here: http://www.andrewscom.com.au/site-section-10.htm Go to 'General accessories' in the second menu table.

[Screwdriverone]

Yep, you can say that again......:)

[mswhin63]

Thanks Eric, such a difficult to site to go through. So very little information on this camera i would steer clear of it.

On another point. I have done some planetary images and I have used a webcam and DSLR camera. Over the time I have come to the realisation that mono cameras are the best with filter as the image resolution after combining is very high. Colour is very convenient but for high quality and low light imagery the mono is hard to beat.

[EricB]

Thanks Malcolm. Andrews' website a rather difficult to navigate to say the least. I have a lot to learn before I can select the right camera. I don't own a DSLR that's why I have been attracted to CCDs. Also, CCDs are light and I am guessing that they would be easier on the scope's balance.

Cheers,

Eric

[mswhin63]

DSLR's are what I use but they are not the best for planetary in general. I don't have a lot of dough to spend either so I only use what I have got. The pixel size for DSLR is a bit large for planets but not so much the moon though.

[Poita]

Save your money and get the DBK, absolutely no question.
Seriously.

I can send you the mono version DMK21 if you want to borrow it for a couple of weeks to have a go. The other cameras in your list will be nothing but disappointing, and the DBK was $499 not long ago, it has only dropped in price because a new model has come out, it is astounding value.

This is an image taken with a C8 and the DBK21 camera.

http://www.flickr.com/photos/jasmel90/6275849504/

Drop me a PM or an email with your address and I can send you the DMK to have a play with.

[EricB]

Thanks very much Peter for your advice. That picture of Jupiter if fantastic. If I could take photos half as good as this one, I would be very happy!

If I understand correctly, the DBK monochrome camera (640 x 480) needs filters to take pictures in colour. Filters are quite expensive. Wouldn't I then be better off bying a higher definition DBK colour camera (1280 x 960)?

All this is new to me . Apologies if my question is naive.

Cheers,

Eric

[mswhin63]

Hi Eric,
Higher resolution will make up the short fall but may not make up for frame-rate. This means that although you can counter the resolution with a higher res camera you may not counter the turbulence in the sky were a high frame-rate is important.
But all in all the colour unit are still very good and much easier to use and process too. I have manage well even with a cheap webcam, DBK can do a lot better irrespective.

[EricB]

Thanks Malcolm. So the ideal CCD camera would be high resolution and would have a high frame rate per second.

I have noticed that the high resolution DSK cameras ($649) only have 15 frames per second, as opposed to 60 frames per second for the cheaper lower resolusion ones ($379). Why the difference? If I had the choice between both (hypothetically), which one should I go for?

I am not very technically technically minded and I would say I have fair IT skills. So if the monochrome presents technical a challenge in terms of processing, I am not sure I would be up to it.

Cheers,

Eric

cheers,

Eric

[mswhin63]

It is a real challenge, I really don't know - I think it boils down to price versus time you can spend processing. I have been and quite likely will be using colour sensors for a while to come, but I know that if I have the money available I will get Mono and filter wheel as my next camera either DSO or Planetary.

I have done reasonably well with hi rez webcam with 5-10fps (https://plus.google.com/u/0/photos/109920401953767744541/albums/5399476938678733681/5694557220521686994) so I would be happy with the same high resolution at the higher rate but it is a really hard decision.

[EricB]

"reasonably well" is an under statement Malcolm. Your pictures are great.When I looked by at the days when I got interested in astronomy as a kid, some 35 years ago, Amateur astronomers could only hope for fuzzy, grainy, black and white pictures of Jupiter and Saturn taken with gear that wasn't available to most (I still have the books and magazines bought then). Technology has changed so much since then!

Cheers,

Eric

[Poita]

The DMK is monochrome, the DBK is colour. Those Jupiter shots are with the DBK colour camera, no filters required.
I have used both the DMK and the DBK, and am not convinced you get a noticeably better result for planetary with the DMK mono + filters vs the one-shot-colour DBK.

In theory the higher resolution camera would be better, but the chip is bigger, so you only end up using less than the 640x480 anyway as the image doesn't fill the chip.

For planetary the DBK21 is easily the best choice in that price-range for planetary work. The higher resolution cameras are good for the Sun (with appropriate solar filters of course) and the Moon.

There are high resolution, fast frame rate, small chip cameras out there, but we are talking in the thousands of dollars.

You can see by those Jupiter shots that the colour DBK21 can deliver the goods, the rest is down to your optics, the seeing and your processing.

[Poita]

The difference is bandwidth basically.
If you double the resolution horizontally and vertically, you quadruple the amount of data that needs to be transferred.

So 640x480 = 307,200 pixels per frame
1280 x 960 = 1,228,800 pixels per frame

Uncompressed that is (roughly) 0.92MB per frame vs 3.7MB per frame
so for the same bandwidth, you can capture 4 times as many frames in 640x480 as you can at 1280x960
These figures assume 8 bits per pixel for each Red, Green and Blue channel, or 24bit colour as it is sometimes called)

To capture 60 frames per second at 1280 x 960 uncompressed would be about 216 Megaytes per second!

USB 2.0 has a maximum theoritcal transfer rate of 60MB per second, it is slower than this in reality due to overheads, but you can see that for uncompressed data, 15fps at 1280x960 = 54MB/s which is as fast as USB2.0 can go.
Of course, compression can allow faster data rates, but the same principle applies, if you quadruple the amount of pixels, and the bandwidth is fixed, you end up with 1/4 the frame rate.

[Poita]

One last thing to add, in theory the DMK with filters should give astoundingly better colour images than the DBK one shot colour, as you get the whole 640x480 resolution for each R, G and B channel.

In a still frame that would probably be true.

In planetary however, we capture a video and select and stack the best frames.
The planets rotate, so you only get a short period of time to get your capture before the rotation blurs out the details. With the DBK you are capturing all three channels at once, so say your total imaging time is 3 minutes. You capture 3 minutes of Red, 3 of Blue, 3 of green all at once.

With the DMK you would only get 1 minute of Red, 1 of Blue and 1 of Green, albeit in higher resolution. Also, the planet has rotated, you have no Red data that is an exact match for your Blue data.

So although you are capturing less resolution per channel with the DBK, you are capturing data for longer, so you end up getting a lot of that detail back, which I think is part of the reason that I have never seen DMK images that blow away the DBK images like people think they will.

[EricB]

Thank you Peter for your very detailed explanations.

Cheers,

Eric

[Poita]

I apologise, the endless rain has driven me slightly mad.

[EricB]

No, that's alright, the more explanations the better.

Talking about explanations, I have just found the following website that reviews the DMK and DSK cameras. It's well over my head, but it could be useful to some of you.

http://www.astro-imaging.de/astro/ImagingSource_DMK21AF04.AS_p01.html

Cheers,

Eric

[EricB]

Hi there. I have done further investigations re CCD cameras (thanks Poita for your help!). The one I am now leaning towards is the Imaging Source DBK 21AU04.AS. It's an entry level CCD, however, it has positive reviews and seems easy enough to use.

I have contacted a dealer who told me that that with my Sky Watcher dobsonian collapsible I could have a focussing issue with the DBK21. Apparently, there may not be enough 'rack in' in the Sky Watcher focusser to achieve focus through the CCD camera. According to the dealer, one way to get around this would be not to extend the top cage fully.

Has any SW collapsible dobs owner had any focussing issue with CCDs an in particular with the Imaging Source DBK 21AU04.AS?

Thanks!

Eric

[Screwdriverone]

Hi Eric,

No, I dont think you will have a problem, I never had an issue with my toucam in my 12" or my 8" Skywatcher in the 1.25" focuser. Or even the DSLR (which is an issue with an MPCC fitted) when its directly into the 2" focuser.

As the 21AU04.AS is basically the same CCD chip size and dimension as the toucam, you shouldnt have any issues with it.

Obviously I cant confirm this, until I buy my own (its first thing on my list).

Cheers

Chris

[Poita]

I'm happy to lend anyone a DMK21 or DBK21 if they want to find out what they need to make it work. I believe the need to move the mirror is only with larger chipped cameras, I reckon you will be right with the DBK/DMK21, but I can send you a cam to try if you want to be sure before outlaying cash.

[Poita]

Just to go back to basics again for anyone reading this thread, all of the cameras on that list, other than the DBK21 are effectively webcams in another housing, and all perform about the same. The DBK21 is in a different league and gives much better results.
Cameras such as the Flea can give better results again, but cost considerably more, and the results aren't stunningly better than the DBK21, but they are better.

[asimov]

If you're thinking about a DBK then you will be by far, way better off going the new model with the 618 chip.

The DBK 21AU04.AS can't do 60 FPS without producing a certain artifact, plus the new chip is leagues ahead in sensitivity. I own both models BTW.

[Poita]

I've used both, and find the new one a bit oversensitive in Red, but haven't seen any side by side compares in the same seeing that make the new camera look far better. I've rarely been able to have enough light to capture at 60fps so it is hard for me to say, if you have a bigger scope it may be worthwhile. The new model certainly is more sensitive, but the old one is no slouch, the images at the link below show what it can do.
http://www.flickr.com/photos/jasmel90/6118317399/in/photostream

Got any pictures comparing the two cams in similar seeing?

It is a fair saving getting the older model, especially as they go 2nd hand for around $250 or so, for someone starting out I thing the older model is the way to go unless you are flush enough with cash that it doesn't matter, in which case you could always get a flea or something more upmarket.
The money saved will buy you a powermate if you are strapped for cash that is a consideration.

Also, the artefact problem only appears to occur if you run certain gamma settings over 100, see here:
http://www.flickr.com/photos/jasmel90/6123941641/in/photostream/

[EricB]

Thanks everyone for your feedback. It's a hard decision to make... but I will get an Imagining Source camera for sure. I will let you know.

Cheers,

Eric

[DJ N]

Hi Eric,

I recently had a Skywatcher 12 inch collapsible dob. I could not reach focus with the DMK21 AU04.AS when inserting it straight into the 1.25" adaptor in the focuser. I was literally only a very small distance off, so I think if I had adjusted the primary mirror so that it was "closer" to the secondary, it probably could have come to focus, but I never tried. However, I did do some imaging with a 2.5x and 5x powermate (not at the same time ;)) with the DMK21 and I had no issue coming to focus.

Hope this helps.

Cheers,

Daniel

[EricB]

Thanks very much Daniel, that's very interesting and confirms the focussing issue with SW focussers. The good thing is that there are solutions.

Cheers,

Eric

[Poita]

In a lot of cases you will be wanting to use a barlow or power mate, so that is a good point.

[mswhin63]

My SW is collapsible and I inserted 3 PVC standoffs to reduce the struts evenly. Worked OK but I ended up adjusting the primary mirror up by a short distance and it was enough.

[asimov]

Hi Peter. Don't have any side by sides right now but I can find a few when I get time. For now though, suffice to say I used the DBK 21AU04.AS for nearly 4 years before I recently purchased the DBK 618 & I can safely say without a doubt my imaging took a big leap towards the better quality end.

It is more sensitive towards the red but that means nothing, you can still balance any live feed data you're about to send up the pipe easily enough.

60 FPS comes in REAL handy for Mars & Jupiter. The link you posted is about onion ringing which you'll get with any cam with an insufficiency filled histogram/not enough gain & not linked with the artifact I'm talking about. Even The Imaging Source have announced that that model cam is indeed out of specs./Won't run correctly @ 60FPS.

Have a search in CN & check out some of Freddy's images, reckon he has some side by sides somewhere with both models.

Yes the 618 is dearer, but if one is serious about planet imaging I think it's the one to snavel. & yes the old model is quite a fine camera as well; it's biggest downfall is the 60FPS problem.

[EricB]

Hi everyone!

I have saved hard in the past few months and I am now in a position to buy an Imaging Source DBK camera.

I have been thinking about getting the DBK 21AU618.AS (the one with the new chip at $499 -Bintel). The camera has a resolution of 640 x 480 and can process 60 frame per minute.

However, my budget could strech to $599, and I am wondering whether it would be better then to get either:

- the DBK 31AU03.AS with a resolution of 1024 x 768 and 30 frames maximum per minute
or even
- the DBK 41AU02.AS with a resolution of 1280 x 960 and only 15 frames maximum per minute

At this stage, I am only interested in lunar and planetary AP. I have a 10" SW GOTO.

Is the difference in resolution noticeble? Is it worth the extra $100? Would a lower frame rate be detrimental to lunar and planetary photography? Would any of these camera be suitable to DSO photography when I upgrade my telescope down the track?

Your advice would be greatly appreciated.

Cheers,

Eric

[Poita]

The difference in resolution is only applicable to Lunar work, and even then, you don't get any more detail, you just fit more of the moon in each shot.

The chip is larger from memory in the DBK31 so the image for planets takes up less space on the chip, so you don't get any extra resolution anyway.
The slower frame rate and lower sensitivity will really make your planetary images suffer though.

I'd get the new 618, and save up for a DBK41 or DMK41 for the moon in the future, and shoot mosaics of the moon with the DBK21AU618 in the meantime.You will get the same level of detail.

-Peter

[Poita]

For DSO work, neither is really much chop. It is possible, but you would be happier with the results from a $200 2nd hand DSLR.

[EricB]

Thank you Peter for you explaination. I must say, I am currently really interested in the Moon, which, at least for a while, would be my primary target. So perhos I should forget the DBK and get straight to the DMK 41, then get a DSL. Hum... DecisionS, decisions!