orion starblast 4.5 eq reflector

[cheezed]

hi i have just bought an orion starblast 4.5 eq reflector whitch has come with 2 eyepieces 15mm & 6mm which say they give 30x and 75x mag but it also says theoreticaly the max mag is 287x how do i achieve this as i would really like to be able to see some sort of features on planets such as the rings of saturn or the bands of jupiter

thanks

[kniclander]

you should see the rings of saturn with your scope at 75x pretty clearly and you might see banding on jupiter likewise. For higher mags you would need shorter focal length eyepieces eg a 3 mm e/p will give you 150x. However, as you up the mag, the image quality degrades and you might find that you don't see jupiter any better at higher mags. 287x is pretty ambitious. Jupiter is best at low mags because it is low in the sky and there is lots of atmospheric disturbance.

[John]

For a 4.5" scope the theoretical max is around 225x rather than 287x - 50x per inch of aperture is generally the recommended max. In reality the conditions in the UK mean that something less than that is the most practical on most nights.

The amount of detail you can see on planets is dependant on the aperture of the scope ans seeing conditions, rather than the magnification used although a 4.5" will show some nice views of Saturn and Jupiter under good conditions.

John

[cheezed]

thank you both for your replys i think i am going to invest in a 3mm ep as jupiter to me is just a tiny ball and i cnt make out much although it was exciting to be able to see the galeaon moons for the first time

[John]

thank you both for your replys i think i am going to invest in a 3mm ep as jupiter to me is just a tiny ball and i cnt make out much although it was exciting to be able to see the galeaon moons for the first time

3mm eyepieces are somewhat hard to come by. An alternatvie would be a 2x barlow lens to use with the 6mm eyepiece that you have.

John