Need help choosing Barlow

[Louis D]

6 hours ago, Alfian said:

The first was a 20mm erecting image eyepiece which by design is already compromised for astronomical use.

A contributor on CN did a tear down and rebuild of the Celestron 20mm erecting eyepiece.  It's quite an interesting read.

[AstroMuni]

I have received my Baader Q-turret 2.25x barlow & Skywatcher planetary 58deg 4mm eyepiece from FLO. Now to wait for clear skies

The skywatcher eyepiece is quite weighty. The near end can be turned (unscrewed?) a little bit - I am guessing this is for fine focussing. Is that right?

Also I read somewhere that this planetary eyepiece comes with a built in barlow which can be removed. Any tips on how to do that?

 

Edited August 2, 2019 by M55_uk

[Louis D]

6 hours ago, M55_uk said:

The near end can be turned (unscrewed?) a little bit - I am guessing this is for fine focussing. Is that right?

If by "near end" you mean the eye lens end, that's the twist-up eye cup that can be raised or lowered to help position your eye at the correct distance to take in the eyepiece's exit pupil properly.

6 hours ago, M55_uk said:

Also I read somewhere that this planetary eyepiece comes with a built in barlow which can be removed. Any tips on how to do that?

This is a negative/positive eyepiece design.  The lower part that inserts into the focuser has a Smyth lens which is an integral Barlow lens matched to the positive section above it that actually forms the image seen by the eye.  Without the negative section, you'll have a poorly corrected Konig-like eyepiece.  I wouldn't bother messing with it.

[AstroMuni]

Thanks Louis. Wish they could have included some basic info with the packaging