Jupiter (1st June 2008)

CCD vs Film? Lots of time vs no patience? Alright, this is your place to discuss all the astrophotography what's and what's not. You can discuss about techniques, accessories, cameras, whatever....just make sure you also post some nice photos here too!
anat
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Post by anat »

Remus.

Nice shot!!!
What is the advantage of the FireWire version over the USB2 one?
For the USB2 version, is an external power supply required?

Anat
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Post by codenamejag »

WICKED!!
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Post by perseid »

anat wrote:Remus.

Nice shot!!!
What is the advantage of the FireWire version over the USB2 one?
For the USB2 version, is an external power supply required?

Anat
I met with Imaging Source asia supplier who is currently in Penang. He told me that the firewire need a dedicated power supply as it only operate between 8-16V. Some laptop firewire didn't meet this power requirement. The frame rate of the firewire is as high as 60 fps. However, depending on your laptop, you may only get 30 fps. Same goes to USB2, which is rated to go up to 30 fps. But some people did get 60 fps after configuring their laptop.

Personally, he suggested that I should get the USB2 version.
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Post by anat »

CK

Thanks :)

For the USB2 version, I am afraid that we may meed to use a power supply because the camera needs 0.5 Amp which is quite high to supply from a notebook. What do you think?
Considering software compatibility, which model is better?

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Post by rcj »

Hi anat,

I use the firewire version with no problems running XP on the macbook pro. Unlike astronomical CCD imaging, planetary imaging is quite demanding on notebook power. Many fail to put this in their budget when they are embarking on planetary imaging, spending most of their money on instruments and then using a laptop with little memory and harddisk space. A single colour channel for the DMK21 at FPS30 for 40 seconds duration already output an AVI file size of 300mB over. Since you need three AVIs (R, G and B), it means one single colour jupiter will "cost" you 1GB of space. And usually, one typical session, you will certainly not just take one set. Normally, you will want to take at least 10 sets if you have the clear sky time and seeing, or in the case of getting the best of the lot. So from there, 10GB per session. You probably will want to try a few nights, and before you know it, you will be yearning for more hard disk space. I have chosen the firewire version because i did not want to "botteneck" the USB ports which is already occupied with external 1TB hard-disks and other peripherals. Also firewire conceptually has a better and more resistant architecture. We have discussed this in the forum before. Firewire is MADE FOR video streaming uninterrupted. USB is more for burst like throughput. This is not to say that USB is not good for this application, firewire is just more reliable long term. DMK has made USB compatible cameras to tailor to a bigger market. Now whether one chooses USB or firewire (on top of what i'd mentioned above) also depends on your laptop. Does it have a firewire port already? Or you will need to buy a PCMCIA card retrofit? Or is your fireport 4 pin or 6 pin?
My macbook pro has a 6 pin firewire port, so i am drawing power from the laptop, which in turn is drawing from the mains. I have not been using battery for this setup so I cannot comment on how long the camera will last if it taps on the laptop battery, but i am sure it will go dead very quickly (perhaps half hour and below). If you have a 4pin firewire port, then you will need to buy a cable that will connect to this 4pin port and then the other end connects to a dc power supply and the rest connects to the camera (in other words, a splitter cable). For the USB version, you may like to use a USB powered hub.

So far, this camera has worked very fine. It can run up to 60FPS uninterrupted. No drop frames at all. I have also tried to stream the raw data directly to a USB connected external harddrive, also no drop frames.

Also, it is wise to have a laptop that has abundant memory (2GB best). You will be getting AVIs based on the uncompressed Y800 standard.
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anat
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Post by anat »

Hi Remus

Thank you very much for your explanation. I will borrow my friend's USB2 version to test with my notebook first and see the result.

Thanks again,
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Post by rcj »

please do. either option, it is a great camera to have!
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Post by Robin Lee »

A well detailed Jupiter! Somewhere around Christopher Go's. Did you use a barlow lens? Did you use Registax v4 to process your photos?

Where's Punggai?
Clear skies,
Robin.

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