sigma octans

speach (Simon) · #1 23-09-2014, 08:18 AM

How on earth do you find sigma octans to align your scope. Been at it for 2 nights now and still not sure that I've got it. Then comes drift alignment, I'm grey now I'll be white or bald by the time I've done!

acropolite (Phil) · #2 23-09-2014, 08:22 AM

Sigma Octans, heard of but never seen. Persevere with drift alignment, it isn't hard at all, nor does it take very long. Finding true north and setting your correct dec angle are a good start, at Astrofest one of the clever committee members had made a triangular template set to the correct latitude, used with a spirit level it gives an excellent starting point for alignment.

PeterEde (Peter) · #3 23-09-2014, 08:27 AM

If your comparing photos off the net with what you see in your scope. Remember your seeing different fields of view.
Google Polaris Australis and you'll find many photos to get you close.
Print one if you can and take photos yourself of the area and compare.

redbeard (Damien) · #4 23-09-2014, 09:50 AM

The easy way is get yourself Alignmaster and a compass and forget all the Sigma... Stuff. Search through my posts and there are detailed instructions on how to use this method. You need to be using equatorial mount though. Hope that helps you.

I'm in Adelaide and my eq mount elevation is 35 degrees, I aim the scope at 172 degrees on the compass for a visual south celestial pole starting point.

Look up on the web for similar settings for your location.

Cheers,

Damien.

AstralTraveller (David) · #5 23-09-2014, 12:02 PM

Magnetic declination in Melbourne is 11* 33' East. So you should aim at 168* 27'. Alternatively, your compass may already be compensated for mag dec, but if that is the case you will know as you have to set it manually. I used to be able to find sigma Octans but I doubt I still could.

archioptic (Nathan) · #6 23-09-2014, 12:21 PM

Quote:

Originally Posted by redbeard

The easy way is get yourself Alignmaster and a compass and forget all the Sigma... Stuff. Search through my posts and there are detailed instructions on how to use this method. You need to be using equatorial mount though. Hope that helps you.

+1 for this. I made one of these to get the mount roughly aligned, then I use alignmaster and it works great.

Nortilus (Josh) · #7 23-09-2014, 04:22 PM

alignmaster and find the star expansion file in the forums...

Nortilus (Josh) · #8 23-09-2014, 04:28 PM

here...did it for you. Find the file in your alignmaster directory and replace is with the attached file.

archioptic (Nathan) · #9 23-09-2014, 04:53 PM

Quote:

Originally Posted by Nortilus

here...did it for you. Find the file in your alignmaster directory and replace is with the attached file.

Thanks, Josh. I assume this gives a broader selection of stars for alignment?

Nortilus (Josh) · #10 23-09-2014, 05:01 PM

yeah...not made by me but another awesome dude named peter.

Rod771 (Rod) · #11 23-09-2014, 11:55 PM

Try this excellent method written by Chris Turton How to find SCP

You can practice with binoculars or finder scope. Thats what I did.

speach (Simon) · #12 27-09-2014, 09:17 AM

I think that I've cracked it. Had a day of sunshine the other day so I, So I used solar tracking speed and got it so the sun didn't move, in the eyepiece for 1/2 hours tracking. Then later with a illuminated reticule eyepiece, which gives me 125 mag, I got a star to stay in the square for 10 mins. Now I've just got to fine tune it to stay longer.