So far, I've been using my stock DLSR. I'm planning on upgrading it to a OSC with LP filters - I won't go into Mono right now, as I like the simplicity of OSC and it would go way beyong my budget, considering all the accessories (filters, filter wheel, etc). I'm considering the ZWO ASI2600MC - or its equivalents, the Altair 26C or even QHY268C, although the 268C seems hard to find in europe right now.
So, on to the practical questions:
1. Any reason to choose one brand over the other? The 2600MC seems like a good choice. Although it comes with 256Mb RAM (compared to 512Mb in the 26C and 268C) it already comes with a sensor tilt plate and some extensor rings. It doesn't come with a power supply so I have to buy that one. The 26C does come with a power supply but doesn't come with extensors or tilt plate, the price becomes somewhat the same if you factor that in. The ZWO is compatible with ASIAIR Pro, in case I want to go that route in the future, though...
2. Do I need an UV/IR filter for the 2600MC? The 26C explicitly says that it has a UV/IR filter built in. The 2600MC only states a IR filter, but the manual shows a graph that resembles a UV/IR filter.
3. Regarding backfocus. I use a Flat6AIII 0.8x focal reducer with my WO GT71. In WO's website, it states that my backfocus is 64.1mm. That means it's around + 9.1mm more than the standard backfocus of 55mm, correct? Also, since I'll be using a 2mm thick filter (L-extreme), this needs to be around 0.66mm more, for a total of 64.7mm give or take right?
4. Also, regarding backfocus, let's see if my calculations are correct:
- Camera sensor to camera flange - 17.5mm
- TS optics filter drawer - 18mm
- Extensors need to be around 29.2 mm. Could I use the 21mm extensor that comes with the camera, and adjust the Flat6AIII to around 8.2 mm? That seems to me that it should work...
5. Again, regarding backfocus. I want to use the Optolong L-Extreme for narrowband targets. But for broadband targets, I'm still unsure what to use. I shoot in a Bortle 4 zone, so not a lot of LP. I could shoot without any filter in the drawer, but then my adjusted backfocus would change 0.66mm (compared to the BF with the filter on). I thought of using a simple UV/IR/Luminance from optolong that's also 2mm thick, just so the backfocus won't change. Or I could use the L-Pro (again 2mm thick) and cut a little bit of LP, although I've read It could mess up with my colors. What would you suggest?