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Old 17-06-2014, 10:52 AM
astro744
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astro744 is offline
 
Join Date: Apr 2007
Posts: 1,046
I can see the Cassini division in my Tele Vue 60 with my 2-4 and 3-6 Nagler zooms. I'll have a closer look again and see at exactly what magnification the division becomes visible for me. Note the Cassini division will become easier as the ring plane opens up and more difficult as it closes.

You should easily see the Cassini division with your telescope and 9mm eyepiece. You should also see subtle bands on the planet itself ranging from yellow to tan in colour.

Any ambient light from your neighbour's light should be blocked directly from line of sight but once blocked will not interfere at all with planetary observing.

Do not expect planets to be 'BIG'. Even with your 6mm eyepiece you will get an image only 1.5x bigger than with the 9mm eyepiece.

I think perhaps before you invest in eyepieces you first get (or borrow if you can) a reasonable quality 2x Barlow and see what type of image you get with your 15mm when Barlowed. Then ask yourself is the image 'big' enough for your liking? Is there plenty of detail there? Then try this with your 9mm when Barlowed. Is the image now too soft and any detail you saw before is just not there?

You will find that with your telescope even 1mm differences in eyepiece focal length under 10mm make a big difference to what the image is like and at higher powers even 0.5mm focal length difference is very noticeable. You may even find adding a quality 3x Barlow and also 20mm eyepiece will give you plenty of magnification range.

Note Barlows are great for fine tuning magnification provided you have suitable focal lengths to play with. Once you have determined that you get best performance from a particular focal length most of the time then you can invest in an eyepiece of just that focal length should you feel you need to or just stick with observing with Barlows.

This is what you can get with the following for example:

Tele Vue 25mm, 20mm, 15mm Plossl and Tele Vue 2x & 3x Barlow.

25mm
20mm
15mm
12.5mm
10mm
8.3mm
7.5mm
6.7mm
5mm

I mention Tele Vue because I know the glass to be good. You may get good results with GSO eyepieces and Barlows in the same combination.

Note at your higher powers you will get a comfortable eye lens and eye relief since you are viewing through longer focal length eyepieces when using Barlows.
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