Telescope proper eyepiece

I have a nexstar celestron130slt goto. I was wondering what eyepiece I should purchase to give me the deepest and clearest image to view Saturn, Jupiter, mars and Venus. I have a 9mm, 25mm and a 2x barlo lense.

FL = 650mm
Aperture= 130 mm (6 in)

I was thinking of getting a 6mm eyepiece. (I have good eyesight)

Also I want to buy a solar filter and I was wondering if anyone knew where to get one that fits correctly. Thanks

The maximum usable magnification for a telescope under good seeing conditions is about 50x per inch of aperture. 130mm = 5.11 inches so your max would be around 255x

Dividing the telescope focal length by the eyepiece focal length will give its magnification, so your smallest usable focal length will be 2.54mm

The 6mm eyepiece would give you 650/6 or 108x and the barlow would double it to 216x.

You could actually use a 5mm eyepiece to get 130x and 260x with the barlow

The solar filter is available at telescopes.net for $60 celestron part number 94139

The 9mm will give you enough magnification for Saturn, Jupiter, and Venus. The 2x barlow will double the magnification if you like. You might want to use the 9mm in combination with the 2x barlow for Mars.

I suggest not using a solar filter. Do NOT look through the telescope at the Sun; just point it at the Sun by making the shadow of the telescope on the ground as small as possible and hold a piece of white paper a foot or so from the eyepiece and it will work like a slide projector, making a projected image on the paper "screen". Turn the focus knob as needed and/or move the paper closer to or farther from the eyepiece to make the image clear. Use the 25mm eyepiece to do this.

Campbel..... Why should he NOT get a solar filter? Are you assuming his maturity based on one question?


Solar astronomy is a very rewarding part of astronomy. I myself enjoy solar astronomy regularly. Buying a Sturdy solar filter from a reputeable and well know company is NOT dangerous.