Short Tube APO vs Achro

I’m toying around with the idea of buying an 80mm short tube refractor as a portable scope for both terrestrial and casual night time viewing. Since short tube scopes tend to excellent at low power, wide field views, what are the advantages of an APO over an Achro where chromatic aberration is not a major problem? For example, I once had an Orion 80mm ST and was quite pleased with the views. If I were to go up in price to an Astro-Tech 80ED or WO Zenith-Star 80SD, what would be the advantage?

Not exactly what you are asking but this has a lot of interesting info:

http://www.astromart.com/articles/article.asp?article_id=398

I had a UO 80 here for a while (an 80mm f/6.something achromat) and used it on the night sky and for daytime viewing. For low power viewing during the day it was fun. For higher powers - which I often use to look at birds - the secondary color was very obvious and very annoying. I wasn't fond of the purplish fringe along edges at all.

I am much happier with a somewhat larger apochromat, and I think such instruments are the best choice for daytime use.

Clear skies, Alan

David,
The MAIN benefit of "APO vs. ACHRO" is "NO CHROMATIC ABERRATION".. past that point, normally you'll be looking into quality of components, like a much better focuser, better tube/dew shield construction, better finish, better glass...


Clear skies!

>>>I’m toying around with the idea of buying an 80mm short tube refractor as a portable scope for both terrestrial and casual night time viewing. Since short tube scopes tend to excellent at low power, wide field views, what are the advantages of an APO over an Achro where chromatic aberration is not a major problem?
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David:

As others have said, the advantage is better quality and color free views. For a few years, I used a TV Pronto as a widefield/terrestial scope. The TV Pronto is a very high quality 70mm F/6.9 achromat...

Nice low power views and it really turned me into a birder. But at 60x-70x, like most birding scopes, it was gone.

A year or two back a friend loaned me his ED-80... My big surprise was that it was sharp and clear at 125x during the day, at higher powers, it is a couple of steps better than the Pronto.

Well, to make a long story short, I ended up buying that particular ED-80 and while I haven't gotten up the courage to sell the Pronto, I use it about once a year. Last night Venus, a real test of color correction was nice an clean...

I think the advantage of the scopes like the WO80SD is that they do a good enough job and they are slick enough that they will keep you happy for a long time to come. There is quite a diffence in what one of these will show and what the ST-80 scopes show.

jon