[mental4astro (Alexander)]

Start doing your observing with low power, using your longest focal length eyepiece. This eyepiece will be your best friend. It gives the widest view, brightest image, and easiest to focus.

It is the most suitable for deep sky objects like open clusters, nebulae, and finding galaxies.

With the planets and moon, use this eyepiece first to locate the sucker you are after, than you can increase the power on it. You will still be able to make out even a tiny but definate disk on Mars, Jupiter, Saturn and Venus. Uranus and Neptune are more readily identified by their distinct colour.

There is also a major limiting factor to the quality of an image, other than the telescope, and that is the atmosphere. If there is a lot of turbulance in the upper atmosphere, the image quality drops markedly. So much so that the majority of the time, the highest usedable magnification is no more than 150X, regardless of the size of your scope.

The ability to use higher magnification is determined by atmospheric conditions, hence it is rare to go much above 250X, even rarer 500X. The only way to improve the odds is to wait for winter when the atmosphere is cooler and so less turbulant, or head for the hills, high hills, as this alone reduces the amount of atmosphere between you and the stars. That is why the major observatories are all located on the top of mountains covered in snow.

To give you an idea on how rare real high power useability is, I was able to crank up my 17.5" dob to 336X twice last year on Jupiter to give me just a good image, not excellent. 336X does not even come close to challenging the limits of this scope. I rarely go above 150X or 200X. Most of my observing is at 67X, my big scope's lowest power.

Just for your info, the way to determine the longest useable EYEPIECE for your REFLECTOR scope:

6 X focal ratio of your scope = LONGEST FOCAL LENGTH EYEPIECE IN mm.

Highest power:

50 X per inch of apeture

Magnification:

focal length of scope / focal length of eyepiece.

Mental.