Milky Way photography with goto GEM mount?

[incrypto]

Hi all, I’ve read so many posts here over the last few months but have never posted. So here goes. :) This feels like a dumb question, but I’m thinking about getting a iOptron CEM40 to grow into but will be using for starters with my new Sigma 150-600mm Contemporary lens on a Nikon D750 and D7200. I figure with that light of a load, I could probably image with the full 900mm when mounting with the D7200 on a CEM40 and then grow into telescopes for years to come. (But would start with more wide field targets.)

Anyway, the point of my post is I also have the new version of the Rokinon 14mm f2.8 for Milky Way and starscapes. I’ve done a lot of googling but can’t find mention of people dual-purposing a GEM for both deep sky and tracked Milky away imaging. I assume you would just pick an object in the Milky Way to track on and use your wide angle lens like you would on a Skyguider Pro or Star Adventurer, yes?

Odd that I can’t find people talking about using a goto GEM for long exposure Milky Way shots. Or maybe I’m just not looking in the right places. 

Thanks!

Steve

[endless-sky]

Hi, it doesn't really matter what object you intend of imaging. Being an extreme widefield object (like the Milky Way) or a close up of a single nebula, the tracking rate of the mount will always be the same: sidereal rate.

The important thing is a good polar alignment (it matters less for extreme widefield), pointing the camera in the right direction, making sure the tracking of the mount is on and set to sidereal, and you are ready to shoot. For widefield taken with an 18mm you won't even need to guide, as the exposure time of the single sub will be short enough and the magnification low enough that you won't notice any star trailings.

The mount you chose should be plenty good enough for all the lenses you listed and even for some small refractors, should you wish to upgrade in the future.

Good luck and clear skies!

EDIT: for Milky Way shooting, what you might want to do is also take a "still" photograph, without traking, of the landscape, exposing for it, instead of the night sky, so that then you can combine the integration of the tracked shots of the Milky Way (where the landscape will inevitably be blurred and "moving") with the single image of the landscape and make a nice final composition!

Edited June 22, 2020 by endlessky

[MarkAR]

As above, get a good PA and then pick a target to goto for framing your shot.

[incrypto]

Thanks both for replying and for for all the info and the process I would need to get this working right. Very helpful and completely clears up my question. You even provided some great bonus info I wasn’t aware of.. thanks endlesssky.  Clear skies!

Steve

Edited June 22, 2020 by incrypto