Does false color show when imaging w/achromats?

I was looking at this http://www.astromart.com/classifieds/details.asp?classified_id=416874 and I was curious if color would show up when imaging with an achromat such as this? Also I dont have much experience with an achromat, is the reason this design is used on DSO's vs. using them for viewing the moon and planets is the inherent problem of color with this design over an APO? Is the color in a higher end achromat such as this very small and difficult to detect? Thanks.

Yes, sorta like this.
http://img.photobucket.com/albums/v699/newtmaker/WaltsM421sttry.jpg

Walt

Gary Smith said:

I was looking at this http://www.astromart.com/classifieds/details.asp?classified_id=416874 and I was curious if color would show up when imaging with an achromat such as this? Also I dont have much experience with an achromat, is the reason this design is used on DSO's vs. using them for viewing the moon and planets is the inherent problem of color with this design over an APO? Is the color in a higher end achromat such as this very small and difficult to detect? Thanks.

If you used a monochrome camera with a filter wheel and refocused for each color, you'd probably get decent results, but I wouldn't expect apo like images.

The problem is the focal length for an achromat is a little different at the red end of the spectrum than the blue, so even if you get the focus right, things won't line up perfectly. I suppose you could scale things slightly in photo shop though.

But for imaging DSO, you don't really need a big lens unless you're looking for image scale. I've seen some beautiful images that were taken with an 80mm f6 apo.

Gary here are a few comparison images showing the different amount of Chromatic Abberation in several scopes labled as APO's. All images were taken with the ST-2000 and each color channel was focused individually. One thing to note is that the brighter field stars will show the CA more readily as in the case of the IC 434 and cone nebula images. There are also other factors at work like varying seeing conditions when each channel was captured, different color balance in processing etc, so this is not flawless comparison by any stretch of the imagination. However it works well as a rough guide.

Hopefully some folks out there have some images through different achromats for comparison also.

Borg 77 ED
http://rattlesnakeobservatory.com/HHflameHaRGB.html

Tak FS-102
http://rattlesnakeobservatory.com/NGC4565.html
http://rattlesnakeobservatory.com/LeoTrioLRGB.html
http://rattlesnakeobservatory.com/Cone.html

AP 105EDF
http://rattlesnakeobservatory.com/N4236LRGB.html