I didn't read this whole thread so I'll apologize in advance if someone already answered this.
A lot of astro-imagers use a dedicated monocrhrome CCD camera as opposed to a OSC or One-Shot color camera (DSLR or CCD). That would explain the monochrome image. Astro-Imaging requires a lot of post processing and monochrome image capture is preferred because its a truer image with all of the data as opposed to a OSC where there is software interpolation of the data in-camera.
If you want to capture more scientifically accurate image data, go with the monochrome. If you want to take portraits of beautiful objects, planets, nebulae -- a color camera can do an excellent job.
Color is more convenient. With the monochrome, you have to use separate RGB filters, and take three sets of images (one for each channel). Then combine them in software. Color is faster (only needs 1 set of images) which is important If the object moves in the sky. A planet may rotate in only 10 minutes. If it moves while you are still imaging, then the perspective is different. You cannot combine the images very well unless you're tracking.
My suggestion: Contact this guy (DugDog) of MyAstroImages.com via his YouTube channel and ask him how he captures his images, i.e. DSLR vs a dedicated CCD or webcam, or about that particular tutorial.
It's always best to get your answer from the source
This guy in the video starts with a greyscaled stacked picture. Others I've seen worked at RGB mode. How is he getting a greyscale type of stacked photographs as mine turned out to be colour? It never looked like his in the beginning.
Cheers and thanks in advance, Peter