How to upgrade from DSLR to dedicated camera

Dan Kearl:
Get a Canon Rebel and modify it. Keep your R6 for day use.

But i would need to buy another lense too :/

Dan Kearl:
The Canon RF lens does not work with an older canon camera?

Unfortunately no, EF can work on RF with adaptation ring, but RF cannot work on EF

You could power the cooled camera with LiPo batteries which are light and compact and get a small laptop to host the necessary software and relay on its battery to get going. My PowerBook Mac does last about 5 hours on battery juice alone, if it isn't too cold. All the other options require you to buy new lens and camera (or used and old but new to you anyway).

I'm afraid you won't find an optimal solution.  

- In order for your photos not to have undersampling, you need more focal length. But that's only possible with a larger lens - and it's less portable. Probably a refractor would be better than a Newtonian, because lens telescopes are more forgiving of the transport shaking.

- As a dedicated astro camera you can choose a One Shot Camera (OSC). Then you save the effort with the filters. Which one is best, other people can tell you better. 

- The ASIair Pro/Plus is small and light. It won't cause you any problems. And it can do everything you need to collect your images on the go. 

- For power on the road, I use a portable power station like this one. It's not overly large, but it's not completely lightweight. 

- To carry everything, a rolling suitcase might be best. 

I wish you the best of luck in your quest to upgrade your gear!

I think the weak link in your setup is the lens and the EOS R with its IR filter is a lesser problem.

I am in a somehow similar situation (except I can shoot from home - Bortle 5 - and I have modified my old 5D mk II … so not the same situation actually , but I have purchased a small and lightweight APO 360/60 and I makes all the difference compared to the 100-400L or even the 70-200L.

I don't know if 360mm is too long for you (but it is I a sweet spot for nebulae on a full frame I think), but the APO telescope is quite cheap (around 600€ with the flattener I think), and lightweight enough to be used on the Star Adventurer (1.5kg). The WO RedCat is also an option with a smaller focal but quite a bit more expensive.

And in the future, using an astro camera on a telescope should be easier than using it with a Canon lens. Or you can also purchase a cheaper modified DSLR.

But I don't think it makes a lot of sense to upgrade the camera before the lens who will still be the weak link in your setup.

Just my suggestion

I understand your challenge very well, since I depend myself on the ability to carry my equipment.  First of all, we both have to accept that this imposes a severe limitation on us, so there's an upper limit of what we can achieve under this restriction. The main challenge and main limitation is the mount. The better the mount, the heavier it is in general. Solutions like the RST 135 come at a very high price, with cheaper solutions we're limited to 5 kg of equipment or less. 

Looking at your images, I see nothing wrong with them. A bit more integration time may help, but I understand your limitations based on my own first hand experience with getting to another location and back. However, I don't believe undersampling is an issue with our images as long as we're limited to single digit integration times. The main advice I would like to suggest is to reconsider your targets. Your equipment is very well suited for (very) wide field work and there are a lot of great examples here at astrobin. With carriable equipment we won't be able to compete for the best close-up of a galaxy.

Please consider that changing your equipment too rapidly will inevitably lead to occasional failed sessions, which hurts a lot if you have significant travel time (and cost). I know what I'm talking about because in an act of stupidity I bought a lot of equipment - based on watching too many youtube astro-influencers - and failed miserably to get it to run in its overall complexity.

This is currently my plan how to progress in astrophotography, maybe it will serve you too:
- Get more experience in collecting clean data with digital camera + lens(es) to get used to the whole process (Lights, flats, dark flats etc.). Start with short focal lengths in the range 200mm or less.
- Improve on processing the data - that's mainly what I currently spend my cloudy nights with.
- Move from an Alt/Az mount to an equatorial mount and learn proper polar alignment (no relevant step for you, since you're already there)
- Increase length of individual exposures, add guiding and learn it properly. I bought myself an MGEN-3 which is a very nice device and supports Polar alignment, too. ASIAIR is an obvious alternative if you don't mind getting restricted to the ZWO universe. Additional weight of a battery is acceptable if you go for a solution like the Omegon Pro Powerbank 48k which adds only 1kg to the equipment. 
- Collect experience with this setup and then decide whether you really need more. There are more than enough wide field targets you can cover with Camera and lenses.
- If you decide to move on, then consider what software ecosystem you want to go for (N.I.N.A, ASIAIR, Stellarmate, astroberry, …).  You need this decission before you buy more equipment, because the platform has to be able to support it. You don't want to end up with equipment that forces you into a platform you don't like. This step may very well be the hardest of all. Honestly, I'm lost on how to decide what to choose. Forums are full of praise and problem reports for all solutions … 
- Set up the platform of  choice and get it to run reliably. This is quite a challenge if you're imaging under extreme temperatures. At this point only replace (or integrate) your existing guiding solution and don't change anything else.
- Move from lenses to a telescope. You may skip this step if you can attach an astro camera to your lenses and your lenses can be stopped down manually,
- Collect experience with dualband filters (may not be possible with normal lenses)
- Optional: Collect experience with an electronic focuser. Based on another thread here at astrobin, I just learned that an EAF may very well make sense even for a normal photographic lens.
- Only now move from a mirrorless camera to an astro camera. 
- From here on you may expand further (filter wheel, etc)

This procedure may look painfully slow and it may take me two or more years to work my way through it. But the basic idea is to keep one foot on secure ground while taking the next step. The advantage is that at any step you may quite easily retract your change and go back to the previous setup as plan B even on location. This is very important if you have to travel to your imaging location, because you don't want to find yourself there with a disfunctional setup.

I'm happy to hear the opinion of more advanced and more experienced fellow astrobin users on how they moved into the world of astrophotography.

Good luck and CS Wolfgang

Alright thank everyone for your replies. Lots of possibilities, that's a though choice ! 
I'll think about what to decide … 
Thanks again for your time, really appreciate it