A star tracker really allows for the long exposures that you need. Get one that is modular and you can add small pieces to as time goes. That way your up front cost is low.
Its at F2.8 and I used 120sec exposure, total of 27 of them. Stacked in DSS for Mac. ISO 400. I have a video on image stacking. Its for narrowband but the principles are the same just skip the first minute of it.
I do have that lens. It is a good lens but it is a telephoto and stabilisation needs to be on even on the Star Adventurer. It is however not the best lens in its class, the Lumix 42.5mm f/1.7 has better glass (less chroma and spherical) and an adapted Chinon 50mm f/1.4 (all manual) will eat it for breakfast (the Chinon 50mm f/1.9 will not). If a fast 50 is wanted and you don't mind the manual focus (astro is manual focus) then the used Chinon may be an option (being a full frame lens you don't get the edge distortion wide open). The E-M5ii is good for having Body-IS for astro but both the Panasonic G7 and GH4 will AF lock accurately on Jupiter (which is not at infinity), which is kinda mind bending.
This is the first time I have ever heard of someone recommending the use of IS for astrophotography. Everyone, myself included have not recommended it because the sensor may move around during the exposure.
@@TheNarrowbandChannel - The IS may steady the image more than its moving about may disrupt it. If you think about it the IS tries to keep the image in one spot. However with an adapted lens e.g. an OTA, you may have to fudge the IS focal length. If for example you fit that old 50mm after setting the IS FL to 600mm, the image dances about like it's drunk. Experiment by fitting to the OTA and alter the IS FL, give it a little nudge to find out what length works best. When you use a dedicated lens, even the massive old 4/3 Bigma, the camera knows the lens characteristics, mass and FL, and compensates IS accordingly. That Bigma is a brute and always wants the tripod and the Body-IS on; the sensor doesn't move unless it has to. Using an iPad gives you a much larger screen to see what is going on, or you can tether with Olympus Workspace. I've been using MFT for ~10y and have accumulated more than a few lenses and assorted clutter.
