Quote:
Originally Posted by gregbradley
there are quite a few refractors in the 120-140mm range that will out-perform the TOA visually.
But: YMMV!
G'Luck!
Peter
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I wonder if you have an out of collimation TOA130. I would be stunned if there were any other scope of the same aperture - AP included, that would outperform a TOA130 to any degree. Unless you prefer high mag views and then 130mm would be a little small perhaps.
If you check out Mr Rohrs APO testing site you will see TOA130 optics are amongst the absolute very best ever.
Like .99 or .98 strehl for every colour channel. That is up with or past AP quality. And practically impossible for a future scope to top because there's virtually no margin left to improve on.
TOA design though is very demanding of perfection in spacings and collimation. ExFSO (Peter) on this site though had a lot of trouble with his TOA130 so there must be the occassional bum one around.
I personally am not a fan of widefield APO views, they are engaging for half an hour and then I want to look at something more closeup. So an SCT or Mewlon would be great for that. And the go-tos of Meade and Celestron are so user friendly.
Greg.
Greg.[/QUOTE]
Whatcha Greg.
Actually its perfectly collimated (or better be!) as I sent it to Takahashi for a tune-up just in case the travel had damaged it.
I'm not ragging the TOA by a long shot and I do agree that its colour rendition is the best out there, but its not necessarily apparent in
visual use.
One other factor mitigates it's usefulness for me: at f7.7 it's neither fish nor fowl.
Not long enough for top-notch planetary or lunar viewing and too long for good wide-fields.
Though you can add extenders/reducers (I have both), these are expensive and just one more thing to fiddle with.
It's weight is also a factor or rather a mixed blessing. While it's a bit of a pig to haul out every time, its also rock steady on an HEQ6 or better and doesn't budge in even the strongest winds (a BIG plus where I live) which is why I hang onto mine!
I was kinda sad to sell my Mewlon, but it just didn't work for me.
My IM815D gives superiour views of the moon and planets and I've only had to collimate it once in about 18 months.
Mind you - it's twice the price of a Mewlon so it darn well better behave itself!