[Brycepj (Peter)]

Hi everyone, It's been awhile but I still have questions. lol

A recent discussion with some other amateur astronomers relating to image magnification with the discussion turning to Barlow and Powermates.
This no doubt has been covered before, ie which one is better and is it worth spend the extra $ for the televue?

The other part of my question I have relates to putting a 5x Barlow into a 2x barlow which was part of the discussion that leads on to focal length. and magnification.
Ok now I'm lost. The comment was that in doing the above (looking a a fuzzy image of saturn) that..."there is probably not enough focal length to achieve focus" ....

Lets use looking Saturn as an example.
So from this with my 10" dob with a 1200mm focal length if I put a 2x barlow into a 5x barlow and then using 6mm eyepiece will I get a crisp clear larger image of Saturn in the field of view, am I also limited by eye piece i use.?
Which now brings me to my next question the magnification limits of my scope which the specs tell me,
Highest useful mag.300x
Highest theoretical mag 508x

Whats the difference??

I also have 20mm, 15mm & 10mm eyepieces.

Hope this makes sense, just want to be sure before I spend $

I also notice 5x barlow/popwermate prices as follows:

Bintell Barlow 5.0x =$69
Orion High power Barlow 5.0x 4 element = $269
Televue Power mate 5.0x = $319.

Is spending the extra dollars worth it? Would you spend the extra $ and buy the Powermate?

Thanks and regards
Peter