A left field view:
1. Most of the time, solar system and solar imaging is not in photon starvation situation thus no special imaging device is needed.
2. A lecture hall screen would be a big screen. It deserves a high resolution feed for the high resolution projector such that students do not see blocky/pixelated images or moving images.
3. A high resolution digital imager feeding a PC thru USB2 tweak images as needed in the PC, then feed PC output to the lecture hall projector with its high resolution output.
This is all digital except the initial image acquisition and final display projection. No standard definition (SD) NTSC encoding and decoding involved to degrade the images.
4. You can display the incoming images in near real time, but they are still subject to the #1` enemy: seeing. "Lucky imaging" rules.
You can run Ragistax to weed out/reject fuzzy images and only stack (many, many more) good images to gain high quality image result. <-- Ask Solar System Imaging group for the current state of art technology to see how much delay it is.
Recent popular imager is ZWO's ASI120MC (or MM) at 1280x960 resolution. price is good.
A hint: buy from vendors that have been specialized in that astro sector. Do not buy an imager which do not disclose exact which image sensor it is using.
Since you are talking about using PST (very narrow band H-alpha), a monochrome imager would give you the best quality. You can tint the screen at a color of your delight (reddish) in or near the final display stage.
Edited by ccs_hello, 09 August 2014 - 10:19 PM.