Star Adventurer calibration.

Started 1 month ago | Questions thread
daveco2
daveco2 Contributing Member • Posts: 931
Re: Star Adventurer calibration.

cheddarman wrote:

daveco2 wrote:

cheddarman wrote:

daveco2 wrote:

Right, just move the mount to put Polaris where the app shows it.

Great, saves a lot of mucking about but do I need to set the graticule with the "0" at the top as in the App, and therefore Polaris will be as shown? With the graticule "0" at the top the camera mount is off centre.

Yes, set the graticule with the zero at the top, then adjust the mount until polaris is at the spot designated by the app.

The camera doesn't need to be aligned with anything on the mount, including the so-called right ascension axis that you show in your picture. You should have a ball mount attached to the piece that gets clamped to the mount so that the camera can be pointed in any direction - north, behind you, east, west, and straight up - all while unaligned with any axis on the mount. Some people attach several cameras to a single mount, hanging off the sides, sometimes pointing at different objects.

Fantastic, most helpful. Am I thinking right that if I want to photo the Orion Nebula, which would be to the south of me, I would have to do the alignment again facing south or can I just change the switch on the side from "N" to "S" because the stars will effectively be rotating in the opposite direction.

As others have said, and as I mentioned, “the camera can be pointed in any direction - north, behind you, east, west, and straight up”, it is all independent of your guiding mount which must remain always aligned with the north celestial axis. Once the guiding mount is aligned with the celestial pole (and Polaris as its closest visual aid), it must remain fixed in position so that it can counteract the rotation of the earth while the camera is pointed in any direction completely independently.

With your camera pointing in a northerly direction, the earth rotates west to east, and with the camera pointing in a southerly direction, the earth still rotates west to east; and in both cases, the mount rotates in the same direction to compensate, with no regard to where the camera is pointing.

In the northern hemisphere, if you were to spin your mount 180 deg on the tripod to align with the southern celestial axis, you would lose polaris and, in any case, the horizon would obscure your view of the southern axis. In the southern hemisphere, you would not have polaris available and would be forced to look south and use the Octans asterism in the southern sky that contains the celestial axis. The N/S switch on your mount is there for that reason, that is for locations in the northern and southern hemispheres.

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