Hello
I just need some confirmation on the following procedure, just to know if it is correctly done or I should modify anything on the listed steps, since I found that after connect the SkyBT bluetooth module the pint-point search precission is lost (the go-to is not as precise as the synscan controller is).
- Polar align the mount
- Star align of the mount (three stars)
- Turn on and connect SkyBT module
- Search for any star (goto)
Thank you in advance and regards,
Yes, that sounds right.
How much different are the GoTo's? Is the object in a 1º FOV in both cases? Is it just not as centered with SkySafari?
When connected to Sky Safari, you will likely see a target reticle drawn on the Sky Safari screen. If what you see centered in the telescope is not what Sky Safari has centered in the target reticle, you can select the object and “align” to it (aka “sync”).
Sky Safari asks the telescope mount (a few times per second) to report the mount’s current Right Ascension & Declination values. That’s how it knows where to draw the target reticle on the screen.
If that does not match what you see, the “align” function (many mounts call this a “sync”) tells the mount the RA/Dec that you are ACTUALLY looking at.
Telescope mounts have many opportunities to introduce mechanical error. While we commonly think the Declination axis is perfectly orthogonal to the Right Ascension axis ... the truth is that it may not be PERECTLY 90° 0’ 0”. But far more common... it that the optical axis of your telescope is almost certainly not orthogonal to the declination axis.
You would notice this if you go-to a star near the meridian, center it in your scope, then have your scope perform a meridaian flip. You’ll notice that it will not end up pointing to the same star. The reason for this is usually attributed to something called “cone error” (I think the “Astronomy Shed” YouTube channel did an episode on Cone Error... what causes it, how to detect it, and how to shim the optical axis to correct for it.)
Anyway, these mechanical errors will cause your mount to regularly miss objects ... even when you have a good polar alignment and star alignment.
Don’t feel too badly when the mount misses your targets.. that’s pretty much par for the course (it’s not Sky Safari’s fault). Sky Safari is using accurate star catalogs and it’s speaking to the mount about RA/Dec coordinates of those objects.
Essentially when you select an object to “go to”, it tells the mount “set the target RA to ____ and the target Dec to ____ and go-to that target” ... your mount goes to what it thinks is that position. (Sky Safari really has no control over this).
