Aligning equatorial mount in daytime?

[jdege]

In prep for 4/8 I've bought a powered equatorial mount for my camera, a sky-watcher star adventurer 2i.

It has a built-in spotting scope, allowing to to be aligned with the pole using Polaris, but for solar photography that won't work.

I can get it roughly aligned getting latitude and true north from map and compass, but are there any tricks I might use to find tune it?

[Sureshks]

Hi Jeff,

You can use the Drift Method to further refine your tracking. See this link. Instead of a nighttime star, you can use the Sun as your target.

https://www.explorescientific.com/pages ... ift-method

Suresh

[jdege]

Thanks.

[setnes]

I have some additional pointers for doing this.

Setting the altitude can be done accurately with a level that gives you the angle. Setting the azimuth accurately then becomes the only thing that requires drift alignment adjusting. With that knowledge you can simplify drift alignment by doing the following.

1) Level the tripod. It is only ever important to have a level tripod when doing a drift alignment. By doing this, you ensure your altitude angle does not change when adjusting azimuth. In these simplified instructions we are going to set the altitude first and (hopefully) not adjust it again.

2) Set the altitude of the mount using an angle level. I like this tool as it is completely analog (no batteries), accurate, and cheap. You just need to match your current latitude.

3) Use a compass or phone app to roughly point the mount north by adjusting azimuth. You don't need to be picky as it will be adjusted with drift.

4) With the scope/camera tracking the sun, use drift alignment to adjust the azimuth only. "up" and "down" in these instructions assumes you are looking at a correct image. Camera orientation, mirror flip, etc could cause that to be different... worst case is a 50/50 guess on which way to twist. It becomes apparent quickly. The important thing is you've simplified the problem to only need to adjust azimuth while drifting.

• If sun drifts up in the image, the camera is drifting South as it tracks.
  Adjust the knobs so the azimuth twists clockwise (looking down from above the mount).
• If sun drifts down in the image, the camera is drifting North as it tracks.
  Twist azimuth counter-clockwise.

So that's how I do drift alignment, but it's also worth pointing out this app. There is a daytime polar alignment routine that might work well enough. To get an accurate alignment you need to calibrate the compass with a shadow. Also, if you had a two-axis mount, there are methods to get reasonable alignment on the sun without needing to do a drift at all, but those are not applicable in your situation.

[jdege]

Even at night I've been set up in places where I didn't have line-of-sight to Polaris.