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Hello, does anyone know if my imaging train looks correct, and if it does, why am i still getting these coma errors?
Could it be incorrect backfocus? Searching the internet makes me think my dslr is 44mm, adding the t ring (even tried a 1mm spacer too) gets me to the required 55mm (assuming that's correct)
I have no idea how to solve this and i feel like I'm just throwing money down the drain fighting this in vien. Help would be much appreciated.
Skywacher Evostar 72ed
Reducer rotator for 72ed (needs this for extra distance to achieve focus, the reducer and adapter alone doesn't allow for enough outwards travel)
Reducer/corrector for ed72
Canon eos 650d
With the ongoing stock shortage it's going to be sometime before I get my hands on my desired scope for my ideal setup.
I'd like to make the most of my current scope until stocks replenish and so I have a few questions about Flatteners and Reducers.
I currently have a Celestron Inspire 100az (details here), a Canon 450D and a EQ3 Pro (synscan).
As I understand, the 660mm focal length makes the scopes FOV too narrow for a mount such as the EQ3. Am I able to add a reducer to bring the focal length down to a level that would be suitable for this mount?
If so, can someone provide some guidance as to which reducer would be the right choice?
This brings me onto my next problem; I can achieve focus with my Canon 450D DSLR in the Celestron 100AZ but by only using the supplied diagonal (here) and my 2x Barlow (here).
I have tried using the 68mm extension tube that came with the T-ring and adaptor (here), inserting this directly into the scope but cannot achieve focus at all. In addition to a reducer, what else do i need to add to the OTA to get focussed?
I recently purchased my first telescope and camera, and now I want to make sure I have the correct Barlow or reducer to couple them together to achieve Nyquist sampling on the camera (or slight over-sampling). In case it’s important, I’m interested in planetary imaging—in theory that shouldn’t matter for this sampling question, but maybe there are other considerations to take into account.
I used this calculator (https://astronomy.tools/calculators/ccd_suitability) and plugged in my info:
Telescope: Celestron 8 SE
Camera: ZWO ASI462MC
Seeing: experimented with this one, but would like to get optics that allow for poor or very poor
Binning: prefer 1x1 to preserve spatial resolution, but could consider higher if SNR is a problem
I’ve seen on several forum posts that people often use a 2x Barlow to couple the two. However, according to this calculator, that will always lead to over-sampling. If anything, it says I should use no intermediate optics or even a reducer.
So my questions are:
Binning: Will I be able to see anything with 1x1 binning, or should I expect to need to bin to collect enough light?
Is there some other consideration that’s more important here than achieving correct sampling? It seems like most others are over-sampling, and perhaps there’s a good reason for this. If so, is there another formula that would let me determine the appropriate optics to buy?
Thanks in advance for any help!