Ad Astra Observatory

I’m trying to decide if the curved field on the AT66ED is going to bug me or not.

I think that it is.

But the field flattener unit is also a focal reducer, which I don’t really want.

Let’s face it: the 66 is going to be useful for about a half dozen objects in my current setup:
– Andromeda (3°x1°)
– Veil Nebula (about 3° square)
– North America Nebula (2°x1.5°)

– Pleiades (about 1° square)
– Rosette Nebula (about 1.5° square)

That’s about it. I mean, there are a few more objects I might take a shot at:
California Nebula, Heart and Soul Nebula, IC1396, D Cygni area.

But really, even M42 is too small for shooting in the 66. You get M42, The Running Man, and a *bunch* of surrounding sky.

As it sits, at 400mm f/6, the 66 produces 3.3°x2.2°, with a curved field. This is large enough to pull in any of the objects I’ve listed, and throw them across enough pixels that I can get a really nice level of resolution.

Putting in a 0.8x reducer brings the scope down to 320mm f/4.8. That’s 4.3°x2.8°, with a flat field. All of a sudden, The Rosette and Pleiades start to get a bit small, covering only about 750×500px. Even the largest stuff starts to have a bit much room around it.. And it’s certainly not going to add any new objects to my target list.

Anyway, the reducer is $150, which is basically what I’d get for selling my DSI-C on the ‘mart.

I found a guy who has been shooting with a Canon and the AT66 with reducer, and I guess his FOV is OK. Maybe the wide FOV won’t bug me.

I have to decide which is going to bug me less, and then go for it.