This post is intended to show where the SCP is located among those stars. It is supplementary to a recently posted article on the methods I use to accurately polar align to the South Celestial Pole.
The gif image further down the page consists of a widefield view which I recorded using my PoleMaster camera. It has a field of view of 11° x 8.25° and I keep it attached to my mount, even though I no longer use the PoleMaster software which came with it.
I find the wide angle PoleMaster camera very useful at the onset of dusk to quickly ensure that I haven't goofed up my rough alignment, before it gets dark enough for plate-solving accurately with SharpCap imaging software in the much narrower 1.6° x 1.0° field of view of my ZWO astro-camera.
I don't use it for any purpose other than to verify that my alignment is close enough to begin accurate alignment using the SharpCap plate-solving procedure.
(I decided not to reduce the image size to fit into the blog column).
Field of view of South Celestial Pole taken 75 minutes after sunset on 9th January 2021.
The orientation will vary by time and season.
1. Yellow lines.
Locate the asterism of four fifth magnitude stars. They are (clockwise):
STAR |
MAGNITUDE |
Sigma Octantis (Polaris Australis) |
+5.44 |
Tau Octantis |
+5.50 |
Upsilon Octantis |
+5.76 |
Chi Octantis |
+5.28 |
Other than Sigma, the names of the stars in the asterism are not particularly important but I try to remember them using the acronym STUC.
2. Blue lines.
Note this straight line of three dimmer stars of magnitudes 6.55, 7.25 & 7.94. I find the line useful for confirming the recognition of the main asterism.
3. Green line.
BQ Octantis is a mag +6.86 red giant, less than 10 arc-minutes away from the Pole. Note the two pairs of stars nearby.
Align to BQ and you will be very close to the SCP.
Here is the Astrometry.net image showing the same image.
Sometimes Astrometry.net goes off line, making the image not fetchable.
The two solid lines indicate the constellation lines between the three "bright" stars (out of picture, mag 3.7,4.1 & 4.3) which form the main triangle of the constellation of Octans.
NGC 2573 is Polarissima Australis, a magnitude 13.5 spiral galaxy which is not visible in this short wide-field exposure. It is 83 million light years away.