Meade DSI III / DSI-Pro III Frequently Asked Questions

 
1. What chips are in the cameras?
The chips in both cameras are the High Sensitivity Sony EXview HAD(tm) Progressive Scan CCD Sensor (ICX285). The DSI III has the ICX285AQ Color (http://www.sony.co.jp/~semicon/english/img/sony01/a6805284.pdf) and the DSI-Pro III has the ICX285AL B&W (http://www.sony.co.jp/~semicon/english/img/sony01/a6805283.pdf)

 
2. What are the sizes and Pixel dimensions of the chips?
Dimensions of chip: 10.2mm (w) x 8.3mm (h); 2/3" (11mm diagonal)
Pixels: 1360 x 1024 pixels (1.40 million pixels)  - Active Pixels
Pixel Size (in microns): 6.43 microns (w) x 6.43 microns (h)  (Square Pixel Array)

 
3. What are the actual image sizes produced by the cameras?
The image sizes produced by the DSI III and DSI-Pro III are exactly the same as the pixel resolution.  Since no squaring of the pixels is performed, the resultant images are still 1360 x 1024 pixels.

 
4. Do the cameras have active cooling (Peltier, etc)?
No, the cameras are cooled via thermal convection in the same manner as previous DSI's.  However, the coefficient of noise is substantially lower in these cameras then their predecessors and by utilizing dark frames specific to a given temperature and exposure length, active cooling is not required.

 
5. How does the CCD Temperature indicator work?
The CCD Temperature indicator displays the temperature of the CCD taken directly from the back of the chip at the completion of any exposure.  This information is displayed in Celsius on the main screen in degrees and tenths of degrees.

 
6. How does the software use the CCD temperature with dark frame subtraction?
When taking dark frames, the software now saves each dark frame with not only the exposure time selected, but also the temperature of the camera at the time of the exposure.  When taking images and Dark Frame Subtraction is enabled, the software will look thru the stored dark frames for the dark frame the most closely matches the exposure time and temperature and will warn you if no dark frame was found within the range indicated by the user in the settings dialogue.  Dark Frames captured while in 2x2 binned mode are saved with a binned extension in the file name and are automatically selected for binned images only.

 
7. Can I use my DSI I, II, and DSI III together at the same time?
Yes, you are able to still connect up to 15 DSI's (I's, II's, and III's) and a single LPI to the PC at the same time depending on your systems capabilities.

 
8. Can I use accessories I have purchased for my original DSI's with the DSI III?
Yes, most likely, all accessories you have for your original DSI will work with the DSI III including filters, nosepieces, faceplate / faceplate adaptors, filter wheels, coolers, etc. The case is the DSI III camera is larger then the original DSI's and as such items such as the Outback Cooler, will not work with these cameras. You will, of course, need to test anything that is not produced by Meade and Meade cannot be responsible for whether these works or not, but in general, most items should work fine.

 
9. Will MaximDL, K3CCDTools, AstroArt, etc. work with the DSI-III?
This will be up to the individual manufacturers of these software products to ensure they are in compliance with any changes to the DSI API.  Imager control will not work until the API is updated and these programs incorporate it.  Image files will still be compatible with these applications.

 
10. Will the new software be made available to original DSI owners?
Yes, the new software will be available from the Meade Web site for download and will work with the original DSI's and the LPI.   Note:  The new version of Envisage utilizes the Microsoft 2.0 .Net Framework as opposed the 1.1 .Net Framework used in previous versions.  As such, if downloaded frpm the Meade site, the user will also need to ensure they also have the 2.0 framework installed on their computer (this is native on Windows Vista computers).

 
11. Can I layer original DSI images with DSI-III images?
Since the DSI III and the Original DSI's have different chip and image sizes, you cannot directly overlay the images together.  However, the chips in each camera are spaced the same distance from the nosepiece and hence, the size of the individual object on the screen should remain close to the same.  Through other software such as PhotoShop, you can manually overlay the images though the sizes of these will still be different.

 
12. Does the color version still have debayer artifacts?
Debayering for the DSI III color camera is completely different then that incorporated in the original DSI I and II color cameras.  This is due to the fact that the DSI III color camera incorporates a true RGB filter matrix as opposed to the CMY matrix in the previous versions.  This translates into a much smoother image and a more direct interpretation of color verses the previous cameras.

 
13. Can I do binned exposures?
Yes, the DSI III cameras incorporate on chip 2x2 binning controlled via the "CTRL" button in the Envisage application.  To use binning, the user need only check the 2x2 binned check box.  The image will then convert in size to 1/4 of the standard image size with the pixels being automatically added together to increase brightness by approximately 100%.  This means that if you take a normal image at a 4 minute exposure, you should be able to take a 2 minute exposure in binned mode and the image will have the same effective brightness.

 
14. Does the DSI III work with USB 1.1?
Meade has indicated that the DSI III will work only with USB 2.0.

 
15. Does the DSI III still have the amp glow in the upper left corner?
The DSI III exhibits some minor amp glow in the upper left corner and in the upper middle of the image.  However, this is only visible in long exposures and and is easily remedied wiht the use of appropriate dark frames.  No impact was noticed due to amp glow during testing and it is substantially less then the original DSI's had.