For landscape + MW, I would start from the horizon and work my way up to catch things before they dip. Away from the horizon it doesn't matter much at all—assuming you're skilled at stitching panoramas…
Cheers,
BQ
In the northern hemisphere you want to do the opposite, start high and end low, start north and end south, assuming you are doing a panorama earlier in the year. You are unlikely to face a scenario where the milky way core is "setting" earlier in the year, if you were imaging in, say, August or later then yes I'd start south and image north, start low and then image high. When imaging earlier in the year you want to start higher so your camera gear is not pointing directly up or close to it, which creates bigger imbalances on a tracking mount and exacerbates tracking errors, plus it makes frame to frame adjustments more difficult and getting overlap correct harder. Starting higher means that you can capture areas of the sky before they get above your camera orientation being >30-45 degrees elevated. Starting in the north means you image into the rising core, which again keeps your camera orientation/elevation lower and weight balance/centering motions easier to handle on the tracking mount. If you start south, imaging the core area first, then as you move north the arm of the milky way rises higher and higher into the sky, leaving your camera pointing higher and making tracking riskier, etc.
I've shot hundreds of Milky Way nightscape panoramas on a tracking mount, I've kept a gallery of roughly 100 of my better ones with acquisition details and equipment information here:
https://www.flickr.c...77720302597732/
I've shot full arch panoramas up to 85mm on a full frame sensor, doing tracked exposures of 2-3 minutes, it's exceptionally difficult and time consuming and not just the acquisition. The post processing requirements at longer focal lengths is also very difficult, doing panoramas at longer focal lengths like 85mm+ can result in a single image having 50+ exposures needing to be stitched. This was a panorama with a Nikon Z7 and 85mmS, tracked, roughly 35 exposures for the sky and another 30 exposures for the foreground, with around 25% overlap between frames, no stacking:
Honestly if you've never done a tracked panorama I would definitely not recommend starting with a 35mm on an APS-C sensor, your margin for error is slim, you have to be very efficient with your time/acquisition sequence so sky/earth rotation doesn't result in stitching errors and foreground alignment problems, plus if you are doing 2+ minute tracked exposures it'll probably take you upwards of 2 hours or more to setup, do all your sky exposures (and any repeats necessary), then do all your foreground exposures, and take down. In that amount of time things, like clouds and weather, can change rapidly. It might start clear and next thing you know you're on your 10th exposure/panel and clouds develop over the core spoiling the whole thing, or the wind kicks up strong and your tracking goes to crap, or it starts getting light/into astro twilight, etc etc. On an APS-C camera I'd highly recommend starting with a 20mm or 24mm lens for first time tracked panoramas, limit yourself to 5-15 exposures for the sky with 20-30% overlap. It'll also make doing your foreground much easier and you'll still get a good amount of detail. I've been doing this stuff for a long long time now, I've taught many many workshops and individuals, spoken at conferences, and I've seen far more people toss the tracker aside for nightscapes than have had repeatable successes with it. Starting with a >50mm equivalent FOV is really tough and probably not going to result in a high chance of success out of the gates, starting with a 20-30mm focal length FOV for a tracked pano will increase your chances of success while still getting a good image and reducing the risk profile associated with the more complex setup. There is a lot of stuff to remember and execute when doing tracked panoramas, to this day I still screw up, forget things, fudge or even forget exposures/panels.
IMO 30-40% overlap is too much if you are imaging at focal lengths above 20mm, especially on an APS-C sensor, for a tracked pano. The reason being you use a tracking mount to give you better SNR via longer exposures, more detail, and better image quality by shooting your equipment at "better" settings. That means stopping down your lens a little bit to sharpen it up, reduce aberrations. Normally you want more overlap for a pano when you are shooting a lens wide open because the best looking stars/most detail you can resolve is going to be a smaller portion of the frame, with a stopped down lens you are increasing that area of the frame that has good stars/good detail. This reduces the need for more overlap. The problem is that when you do tracked multi-row, sweeping panoramas of 90+ degrees you risk missing a portion of the sky during all the frame to frame movements, so you have to be really aware of your alignment, your acquisition sequence, and how many/much adjustment(s) you've made during the process. These days I use an indexing rotator as well as a combination of Z and V brackets to take the guess work out of the alignment and frame to frame adjustments, this is what my setup looks like now with some components that I've personally designed and 3D printed:
Anyways, I could talk forever about this stuff, I'd be happy to answer more questions.
