How to find the South Celestial Pole (SCP) almost accurately.
It is always difficult to find the (almost) exact spot when you are aligning your telescope. I hope this will help!
Why find the SCP?
- To set up your Barn door mount (Scotch Mount, Star Tracker) to ensure round stars on your image.
- To do a proper polar alignment with your Go To Telescope on a wedge to take astro photographs.
- To store it in your head and show your knowledge at a star party.
Why this method?
- You get pretty close to the SCP without guessing where the lines from wherever should cross.
- With a green laser mounted on binoculars (on a tripod) you should get very close to that magical unmarked spot in the Southern hemisphere. Not even the North star is precisely on the dot.
Whose idea?
When I was setting up my Barn door mount to take photographs at the Britstown Star Party (6 - 9 August 2010) it all came back to me. I used this pattern some years ago to set up my SCT at Boyden Observatory. I tried to find it on the web, but Google was of no help. So if I stole the idea from someone, please let me know and I will credit you.
What you need to plot the SCP
- 7 X 50 m binoculars
- A steady hand or a tripod for the binoculars.
- A green laser pointer will help. Mount the laser and binoculars on a tripod.
Adjust the laser light to show in the center of the binocular view.
How to find the SCP
1. Find the constellation Octans. Use a planisphere, software like The Sky 6, Cartes du Ciel etc. or Map 1 below.
2. Zoom in and plot the Table mountain figure on map 2. It is almost magnitude 6 stars. So be patient. When you get familiar with the star environment you will find them with the first pointing of the binoculars. PRACTICE!
3. Use the third map to pinpoint the SCP
- Upsilon Octantis
Object name: SAO 258932 Other ID: HIP 111196 Magnitude: 5.76 Flamsteed-Bayer: Upsilon Octantis
- Tau Octanti
Object name: SAO 258970 Other ID: HIP 115836 Magnitude: 5.50 Flamsteed-Bayer: Tau Octantis
- Sigma Octantis
Object name: SAO 258857 Other ID: HIP 104382 Magnitude: 5.45 Flamsteed-Bayer: Sigma Octantis
- Chi Octantis
Object name: SAO 258799 Other ID: HIP 92824 Magnitude: 5.29 Flamsteed-Bayer: Chi Octantis
I hope there is method to my madness.
- Connect Tau Octantis and Chi Octantis
- Draw a 90° line through Sigma Octantis. This line will pass very close to the SCP.
- Sigma Octantis is 01°02'37" from the SCP
- The star (mag 6.8) is 00°13'41.818" from the SCP.
How close do you want to get to the SCP?
Charts: TheSky6
Enjoy!
Hannes Pieterse
ASSA Bloemfontein
South Africa
