SW 100ED vs. SW Equinox 100ED vs. Ostara 102ED

[Stratis]

Can't believe I missed this entire thread debating the scope that I wrote a review for 

I think most ground has been covered and last I spoke to Emad he was after the StarWave which I think should be a good buy if he can deal with the blue undercorrection or stick a minus-V on it... Altair seem to be pretty good at ensuring good optics come out of their shop so hope it works out for him. I'll forward the minor correction that the Ostara is quoted as having 'FPL-53 equivalent' glass with HKD-61 as a likely candidate, so should marginally outperform an FPL-51 lens with equally good figuring.

I think if we could get a Vixen 102 we'd all love the opportunity but sadly they've gone premium these days 

Speaking to the question of 80mm vs 100mm, I personally found it the difference between looking at the sky and viewing the sky... the extra bit of aperture seemed to return the sky to its familiar star-speckled character against the more rarified view in an 80mm. I got the same feeling looking through a 90mm Mak, I could view objects, but not the sky itself.

I keep my ST80 around for terrestrial viewing and quick trips but whenever I need to grab-and-go I follow moriniboy's example and grab the Ostara  . My only other scope in that aperture bracket was the SkyWatcher 127 Maksutov which I've just sold as it never gets used with the 102ED around.

[John]

... I'll forward the minor correction that the Ostara is quoted as having 'FPL-53 equivalent' glass with HKD-61 as a likely candidate, so should marginally outperform an FPL-51 lens with equally good figuring.

I can't find a reference to a glass type called HKD-61.

I've found these, with their Abbe Numbers, from their manufacturer catalogs - is one of them the glass you are referring to ?:

FPL-51 (Ohara): 81.54

H-FK61 (CDGM): 81.61

FCD1 (Hoya): 81.61

OK-4 (LZOS): 92.1

FPL-53 (Ohara): 94.93

CaF2: 94.99

If the mating elements have been well chosen and the figure, polish and mounting are to a good quality then all can produce very satisfying results I reckon 

[Stratis]

*sigh* I think I have a form of mnemonic dyslexia.

My brain has combined HFK and FCD into HKD through some magical idiocy.

[derekorion]

Have you still got the Ostara 102mm.  If so, after using it since 2013, what's your views now? Apologies if you've said earlier in the thread that you sold it etc.  I can only read so much in a day. I have chance of one without finder. I don't know it's optical quality and there are no test reports. But it looks in good condition.