I use ASPA with the eyepiece, I usually get it around 3. The Azimuth can be really frustrating.turfpit wrote: ↑Tue Aug 14, 2018 9:56 amWhat mount do you have?
I used to own a Celestron CG5 and now have a Celestron AVX equatorial mount. These mounts have a facility called All Star Polar Align (ASPA). I have used this to good effect. ASPA works by allowing the user to select any star in the sky and use that in combination with the Alt/Azm adjusters to achieve polar alignment. I use ASPA with a camera inserted in the scope rather than an eyepiece. Turning on the reticule in the capture software increases the accuracy. The steps I take are:
- Get rough polar align by looking through the mount's polarscope or the vacant polarscope slot.
- Fit camera into scope and turn on software reticule.
- Slew to appropriate star (I am using Altair or Deneb in August for polar alignment).
- Follow the handset instructions via ALIGN > POLAR ALIGN.
The process takes < 5 minutes.
- Get the handset to report the PA accuracy.
I commonly get reported alignments like this:
I regularly achieve accuracy of 1", 1" and have managed 1", 0". I have never got 0",0" but given the courseness of the Alt/Azm lever threads not surrprising. I don't know/care how the accuracy stacks up against other PA methods but it works for me and had zero cost above the original equipment purchase.
So how accurate is this method? See my Astrobin https://www.astrobin.com/users/turfpit/. The M31 is 60x60s unguided - which looking at the stars seems good enough. Several other images are 30x60s, which again don't seem to have star trails. I consistently get decent results with 60x60s using ASPA.
I carry out mount alignment (2 alignment stars + 4 calibration stars) with the camera in place. This eliminates optical shifts when changing from eyepiece to camera and is a more comfortable way to align.
Why am I not using Sharpcap's PA? Because 1) I have only just purchased a guide scope, 2) I sometimes capture on a Linux laptop.
I suppose other mounts will have a similar facility. Hope this gives you some ideas.
I should try the method you use next time.