由 社長 » 2011-08-16, 08:10
Frequently Ask Questions about the LSi Camera
• What are the advantages of this camera over other cameras (like DMK41…)?
- The main advantage is the significant lack of post-processing you have to perform on the images. What is the point of having to take and then sift through 600+ images to pick out the best ones, then process them up and then combine them all to get one good image With the LSi camera you are able to take 10 good images, process them up and stack them together? The real key to this is the dynamic range. We have had imagers blown away when they take the first image; do a very simple contrast stretch and have one image with all of the prominences around the outside and loads of surface detail.
Unfortunately planetary imagers are used to having to take thousands of images, going through and picking out the best ones and then adding these together to give the final result. The main reason for this is that typically the planetary exposure times are about 1/10th of a second and therefore the turbulence over that long an exposure (even though it is still pretty short) can be quite significant. By taking hundreds or thousands of images, they can select a few tens of those least affected by seeing and combine these into a high resolution result. With the sun, however, the exposures are much shorter and therefore all of your images are much less affected by the seeing conditions. You do not need to take thousands of images, but just a few with the excellent dynamic range (number of grey levels) offered by the LSi. A quick and easy contrast stretch and sharpening filter will give you an excellent finished image, without all of the hassle of selecting and stacking hundreds of frames.
The LSi camera uses a 2/3” format CCD which is ideally suited to fit the whole of the sun on to the CCD in one image. It also has larger pixels which have larger ‘full-well depth’ and incredibly low read noise which allows the camera to produce a very high dynamic range. It uses a 16bit A/D converter giving 65,536 grey levels compared to 8bit (256 grey levels). To get the best image from an 8bit camera you need to take lots of over exposed images and average them together to build up the good data on the prominences and then take a lot of images, under exposed, to get the surface detail, and then add all the frames together. Because this LSi camera has such a large dynamic range, you are able to capture both the prominences and the surface detail in one image and with the exposure times so low, you can almost freeze the seeing conditions.
• How many frames per second?
- 1 frame every 0.6 seconds.
• Possible exposure times?
- 1/1000th second to 90+ minutes
• Can the camera (and the software) also be used for deep-sky imaging? Is there a cooling solution?
- Yes the camera is ideally suited for both solar and deep-sky imaging. It has a single-stage peltier cooler which cools the camera to approximately –30C below ambient and has set-point cooling so you are able to set the temperature to the required point.
• How does the LSi camera connect to my computer?
- The LSi camera comes with a USB2.0 cable.
• What power supply cord do I need to purchase?
- The power is derived from a power supply cord which is included in the package.
• Can I use it to create videos?
- It is possible to take 1 frame every 0.6 second and automatically save the images. You would ten put them into Regi-stack and create a movie. It will not have as many frames but it will have more detail.
• Is power supply only for US standard, or is there a power supply for European standard (230V AC)?
- The supplied power supply is an auto-ranging switch-mode power supply and will accept 100 – 240V AC.
• Is it a black & white or a color camera?
- This is a monochrome camera.
• What is the connection to the telescope?
- The LSi camera has a T2 thread in the front but also comes with a 1.25” push-fit adaptor and a 2” push-fit adaptor.
• What software is included? Is it special software for solar imaging?
- The software supplied is aimed at solar imaging but additional free software can be downloaded for deep-sky imaging. It will also work with third-party software such as Maxim DL, & AstroArt.
• What computer systems is the software compatible with?
- The software works for all versions of Windows (even 64bit Windows).
• What accessories are available?
- The camera comes complete with software, adaptors, power supply and all contained in a presentation ABS case to keep it clean and safe.
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