Eyepieces for DSO

[alanjgreen]

Ady Alex,

I was looking at the two choices and I just thought The two APM eyepieces are very similar in focal length at 15 and 18

15 gives x80 in your 1200 mm scope

18 gives x66 in your 1200 mm scope

you are unlikely to notice much difference in the view from one or the other.

you may be better getting something in the x150 and only one of the above.

Alan

[StarryEyed]

Ady

I would suggest creating a list of objects you would like to observe. Specifically the size and magnitude. This will help you work out the true field of view you require to see these objects in your scope. 

You should then consider the magnification which depending on your sky can make some objects easier to observe than others.

This will give a good idea of the focal length of the eyepiece and it apparent field of view. 

You should calculate the exit pupil for eyepieces you shortlist to ensure this works for you.

A spreadsheet is good for this.

At this point you will be in a very good position to research on the internet. 

Keep observing with your current eyepieces and make notes of what you can and cant see.

In a month or two you will have a good idea of what you are really looking for and will appriciate you choice much more.

Sometimes the best choice is not the cheap one and such a choice is worth saving for.

Best of luck.