RAPAS for use in the South


Anyone in the Southern H. using the RAPAS? Can you use it effectively in light polluted skies?


M Hambrick

Hi Bob

I don't live in the southern hemisphere, but the RAPAS reticle is set up for both northern (Polaris) and southern (Sigma-Octans) hemisphere use. I don't know how bright Sigma Octans is, but you should be able to do the alignment as soon as you are able to see the star through the RAPAS. The 25 X 200 mm objective has enough light gathering power that I can see Polaris right after sunset. 

Hope this helps.


Len Fulham

I have the RAPAS and have used it in Mount Isa and S-E Qld areas (dark skies). Sig Oct is hard to identify unless you have studied the star patterns well, and is faint enough that the reticule (at min brightness) with good batteries will obscure it. I find I have to turn reticule on/off and use reticule 'after glow' to make adjustments - quite doable. Easier as the batteries get low. Not something I can do in twilight and I expect harder if there is serious light pollution but should be doable.

If you are arbitrarily panning the mount to try and find Sig Oct, I think it is impossible. You need to be 'almost' polar aligned using a daytime routine or careful adjustment with a smart phone level & compass. Once you recognise the correct star pattern in the RAPAS, then alignment is quick and accurate (provided you have calibrated your RAPAS via a proper drift alignment first).



Thanks Mike and Len.

Takeaway then is order the RAPAS I think.