Hi folks, first post here, nice to meet everyone.
I've been dabbling in astrophotography with a fixed alt-az tripod and a dslr, and I'm now thinking of moving up in the hobby a short step. My budget is a bit restricted (~1100 usd) so I've sort of narrowed it down to a few possible routes.
First off, I'm planning on getting a SkyWatcher Star Adventurer for about 425$ as a mount. This is partly budget related but also portability related, as I'm travelling somewhat nowadays as a student so lugging around a go-to mount is just not an option for me at the time being; barring one exception which I'll mention at the end. I'm aware of its limitations but I'm quite excited to see what I can do with it especially with guiding, as some folks report good results. This also applies to why I'm looking at lenses and not scopes, as most seem a little too bulky for me at the moment.
My main interests are in imaging nebula, some bright galaxies and star clusters (perhaps I would say everything except very wide-frame photography), with a focus on using narrowband filters to get past most of the light pollution that I'll have to deal with, as even though I'm travelling its still mostly between cities and my dark sky time is currently very limited. I currently have a DSLR, which I will talk about below (I'm scared of astro-modding it). I've allocated about 150$ for a ZWO Ha filter for starting off with.
Option 1: DSLR + Lens + Guiding
This seems like the cheapest approach as it doesn't involve getting two cameras (one for guiding one for imaging) but currently I'm quite hesitant to astro-mod the DSLR as I'm worried about breaking it and being stuck without any form of imaging for some time. As such I'm not too convinced about its performance with Ha, though I've heard that its still "alright" stock so to speak (especially with longer subs).
I'm looking at the ASI120MM (either -S or Mini) for guiding.
Option 2: Astrocam + Lens + Guiding
With this route I'm looking at the ASI178MM Mono for imaging and the same ASI120MM as mentioned above for guiding. I've narrowed down the accessories I'll need getting it to work with a DSLR lens and they won't add too much budget-wise for me. The DSLR is also used of course as a secondary, so this is more of an Option 1.2 in a way...
This does however open up the possibility of me bucking up and trying to astro-mod my DSLR later as if something breaks I'll still have the 178MM. It also lets me do Narrowband Ha or maybe duo-band Ha/OIII with a monochrome camera and its extra sensitivity.
I understand its uncooled and that its main use is for planetary imaging, but the results I've seen so far in pictures some folks have shared have been stellar and honestly more than good enough for me. I'm aiming more for a wide amount of targets to image with decent quality at the moment rather than supreme image quality, as I'm guessing that will require a cooled astrocam and a sturdier mount (someday).
As for the lenses, I'm keeping things extra limited on budget to about 200$, though if you've got any good alternatives under 300$ I would very much like to hear about them. The top two contenders are the:
Canon EF 75-300mm f/4-5.6 III: https://www.bhphotov..._Autofocus.html
Mitakon Zhongyi Creator 135mm f/2.8 Mark II: https://www.bhphotov...f_2_8_mark.html
I'm leaning toward the Canon lens at the moment as the variable zoom seems like it will be handy for framing versatility. If I go with the ASI178MM the equivalent focal and fstop at 70mm would be 318.5mm f/18.2. Veeery high F stop I know, but the focal length frames a lot of targets well. It does lead to a rather broad pixel ratio of 5-6"/px though which is a bummer. If I zoom in all the way though to 300mm I get 1365mm f/25.48 and a much better pixel ratio of 1.6"/px.
So this gives a focal length range of 318.5-1365mm and a focal ratio range of f/18.2-25.48 and a variable pixel ratio of 6"-1.6"/px. I'm aware though that those higher focal lengths would be demanding on polar alignment, but I'm hoping that with a good polar alignment using PHD2 SPA and Drift align along with the guiding camera I can track efficiently enough for perhaps 60 seconds at 135mm (615 equivalent) or (on a windless night) 200mm (900 equivalent) and perhaps lots of shorter subs at 300mm (1365 equivalent). I would really like to hear some thoughts on this, as though it seems to make sense in my head I'd like to know about its practicality. I am very curious to hear what you guys think of the very high f/stop; by my understanding it doesn't limit the amount of light coming in, just the clarity right, as it is an equivalent value?
The alternative competitor the Mitakon makes me think of the Samyang 135mm (which I really can't consider, at 500$) though I've heard that it suffers from some CA and Coma. I'm sure the Canon would also have similar hurdles, but I'm assuming that due to higher fstop they might be less pronounced? The fixed zoom is a bit of a bummer and honestly I'm 80% convinced on going with the Canon at this point just for the variable zoom.
But yea I understand that none of these options are optimal, but moving up in the hobby is an itch I need to scratch and I really can't stall until I save enough for a sturdy go-to. This obviously hasn't stopped me from thinking about it however, i.e blowing the whole budget on a light go-to... something like an iOptron cem26 does barely fit in the budget and its very light at 5KG for the mount (I can't consider the SW EQ-35m since its way too heavy for me right now). My hesitance to go down this route is that it will most likely be some time until I can save up to buy anything else for the setup, so for quite some time it will just the mount, the DSLR and a cheap lens I can squeeze in.
1- Canon DSLR+Guiding or DSLR+ASI178MM+Guiding?
2- Canon EF 75-300mm or Mitakon Zhongyi; or your best bet for under 300$
3- Blow the budget on the Go-To (iOptron Cem26)?