|
The problem noted above is most pertinent for OSC, because you get chromatic aberration at any single focal point. In theory, you can do LRGB imaging, provided you re-focus for each filter change. In practice, achromats tend to induce bloated stars on the blue channel regardless. They are fine for narrowband, as the bloating is minimized.
I speak from experience, imaging with a SW120 achro. There are a few images in my Astrobin (see sig) that show this for some emission and planetary nebulae.
Extension tube noted above is for finding focus.
|