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There is something that makes me think practicality.
We can all agree that a long focal length scope is better suited for planetary use than its short length brother which would be best suited for dso viewing or guiding/photo.
We can take those two (refractors) as an example: 90/900 and his brother, a 90/500 (and we will be using Plossl EPs)
Exit pupil is an important factor in viewing comfort.
Exit pupils are dependent on the scope's focal length, the EP's fl and the main lens diameter.
For example, to acheive 100x in the 90/500 we will need a 5mm eyepiece and to acheive the same mag in the 90/900 we will need a 9mm eyepiece.
The exit pupils of both scopes in those configurations will be 90/100=0.9mm
The theoretical magnification limit for both scopes lies at about 180x.
It is true that to reach this 180x you will need a 5mm EP in the 90/900 and a "2.8"mm EP in the 90/500 and those will probably make for an eyelash brushing eye relief... But looking at exit pupils up to 100x, those scopes do not seem to complement one another, but rather replace each other.
So, ignoring abberations, and not taking into account eye relief so much, wouldn't the faster scope be almost as practical and easy on the eyes for high-ish magnifications as the slower, heavier, harder to mount in the wind scope?
just my evening neurons buzzing...
As part of my equipment reduction, I'm selling the following items:
Vixen HR 3.4mm (like new) £200 Vixen HR 2.4mm (like new) £200 1.25" Lunt Herschel Wedge (prism, ND filter, and wedge housing structure like new. Locking screw requires tapping and threading. Hence the discount) £80 SOLD The Vixen HR are the best eyepieces I have ever owned. A few members on CN matched them with the Pentax XO. No light scattering and incredibly sharp. In my opinion colour tone is neutral and sits in between the Docter UWA and my Zeiss Zoom eyepieces. Eye relief is comfortable if spectacles are not used (which should not at high magnification).
The Lunt Herschel Wedge is an excellent tool for white light solar observing using a refractor. It works even better when combined with a Baader solar continuum filter in my opinion. The hole of the locking screw of the solar wedge requires tapping/threading. Apart from that, everything is in excellent conditions, essentially indistinguishable from new items.
Caps and boxes (hard case for the wedge) are included, of course.
Price includes 1st class RM signed-for. Payment via PayPal (as friends) or bank transfer. Collection from Cambridge also available if preferred.
Thanks for looking,
I am very new to everything to do with astronomy/looking through a telescope and I have recently bought my first scope (a 8" dob) which came with a 25mm and a 10mm eyepiece but I am looking to upgrade but don't know what is good.
Any help or advice on what eyepieces I should be looking at buying would be much appreciated (budget is anywhere form 0 to 100 pounds per eyepiece)