One can use a point & shoot camera for taking high magnification video of the the Moon or planets.  The smaller lens on point & shoot cameras match up well with the size of the "eye" lens of most 1 1/4" eyepiece.  Because of this, when the camera is zoomed in, the image on the camera view screen will have little or no vignetting.

You will need a clamping device such as a Scopetronix EZ-Pix II (I think this is no longer manufactured but there are other similar devices) to hold the camera up to the eyepiece.   I have  1 1/4" a 2" versions of the Scopetronix device.  One will need to use eyepieces that don't have rubber eye guards or will need to remove the eye-guard.

The Moon is bright and pretty easy to  video this way.  Jupiter is fairly easy as well.  Saturn, being notably dimmer, will not take as much zooming in or magnification but still can be successfully videoed this way.

These videos can viewed as-is, or the video frames can be stacked into high quality stills.  I use Registax for this. Note- you will need to convert the video to uncompressed AVI format.  There are free converter applications for doing this

I had very limited success with trying to hold a smart-phone camera up to the eyepiece of a Celestron 128EQ on an equatorial mount.

Things got quite a bit easier when I invested in an inexpensive Phone Clamp that clamps onto the barrel of an eyepiece. The cheap Phone Clamp had a couple of degrees of freedom for aligning the phone with the eyepiece. Hard to use. Easy to knock out of alignment.

I purchased a Celestron Phone Clamp that had more adjustments for alignment, and it greatly simplified capturing quick images with a phone. Once the phone is clamped, there are three knobs to turn for the XYZ alignment of the phone lens with the eyepiece lens.

ScottE