Ascension 102ED Triplet APO

[merlinxlm]

Has anybody on the forum had any experience with the Ascension 102ED Triplet APO. How does it compare with the Sky-Watcher Evostar 120ED DS-PRO APO in performance and image quality? Both are about the same price, but the 102 ED has the Triplet Japanese FCD1ED

glass, where as the 120ED has the Optics made in FPL-53 glass. Is the aperture more important than the quality of the glass.

Thank you.

[John]

I've tried an ED120 but not the Ascension 102ED. The ED120 is excellent though and I can't see any way that the 102 triplet would beat it for visual observing. The triplet might have some advantages for imagers I guess.

John

[GazOC]

I think this is the same scope that Orion (and others) are selling. FWIW the Skywatcher has the aperture and the higher grade glass (FCDED1 is the equivilent of FPL-51), albeit its a doublet and the Ascensio is a triplet.

[merlinxlm]

Would there be much difference in image quality and sharpness between the two.

Thank you.

[Ant]

I'm really stepping out of my "confort zone" with this, so please go easy on me .

But I'm sure that I've read somewhere that it is much easier to make a really good APO Doublet than a APO triplet.

I thought that the FPL-53 was better than the FPL-51? Which would make the glass in the 120 Doublet better than the glass in the 102 Triplet?

Ant

[johninderby]

From what I understand the Ascension (Meade) 102ED Triplet APO is almost as good as the ED100 with just a tiny bit more CA than the ED100 but overall there's very little in it. While the triplet is theoretically better, it is harder to make, so at this price level the easier to make doublet is usually a bit better and it is easier to maintain consistent quality. The triplet's quality will vary more. Also the triplet takes longer to cool down and the scope will be more front heavy.

The ED120's aperture will definitely give it a big advantage over the 102 triplet, so in a contest between the two it's the ED120 all the way. The above only applies at this low price point. When you get into high end scopes it all changes.

John

[adamsp123]

Definately there is more potential for cumalitive errors creeping in with a triplet design hence the top of the range ones cost a small fortune due the large amount of human "intervention" to get it just right. I cannot comment on the Ascension 102 but I am extremely happy with the quality of my 120ED.

As far as the type of glass and the effect it has on a scope I really don't know but the bottom line is does the particular design work well.

[coliea]

Excuse me if I'm overstepping the mark but another option might be the Stellarvue 102ED. It's a bit more expensive but I was in a similar position last year and after much debate went for the SV scope and haven’t regretted it. With or without the feathertouch focuser the build quality is excellent and while Stellarvue don't advertise glass type CA is almost non-existent.

I got mine through the UK SV dealer but I’ve since noticed excellent deals on Stellarvue’s official eBay shop and would look there first if I was purchasing again. The reviews of this scope including one from Sky at Night magazine have been excellent and are available here: SV 102mm ED doublet refractor telescope

Sorry if that just make things more confusing

Col

[Izar]

I use a Chinese made Triplet with FCDED1 glass, and

a Takahashi Triplet with FPL-53 and Canon camera.

My eyes struggle to see any real difference between

the images taken with each set-up.

My FCDED1 scope is giving me near Tak quality images

for a much much cheaper price.

[coliea]

I got mine through the UK SV dealer but I’ve since noticed excellent deals on Stellarvue’s official eBay shop and would look there first if I was purchasing again.

For example here: Stellarvue 102ED 4"

Hands on Optics are an officail US Stellarvue dealer.

[FLO]

While the triplet is theoretically better, it is harder to make, so at this price level the easier to make doublet is usually a bit better and it is easier to maintain consistent quality. The triplet's quality will vary more.

Yes, that is my belief too. It is significantly more difficult to produce a triplet so at this price-point the FPL-53 doublet will almost certainly win.