Which entry level CCD imaging for planetary photo?

[EricB (Eric)]

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 (Malcolm)]

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 (Malcolm)]

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 (Chris)]

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 (Eric)]

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 (Chris)]

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

[mswhin63 (Malcolm)]

Originally Posted by EricB

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.

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 (Eric)]

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 (Malcolm)]

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 (Peter)]

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 (Eric)]

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 (Malcolm)]

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 (Eric)]

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 (Malcolm)]

Originally Posted by 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

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 so I would be happy with the same high resolution at the higher rate but it is a really hard decision.

[EricB (Eric)]

Originally Posted by mswhin63

I have done reasonably well with hi rez webcam with 5-10fps .

"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 (Peter)]

Originally Posted by 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

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 (Peter)]

Originally Posted by 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?

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 (Peter)]

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 (Eric)]

Thank you Peter for your very detailed explanations.

Cheers,

Eric

[Poita (Peter)]

Originally Posted by EricB

Thank you Peter for your very detailed explainations.

Cheers,

Eric

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