New amazing 152mm ed apo northgroup

[musab]

http://www.youtube.com/watch?v=DoEOb-LkUCI

http://www.youtube.com/watch?v=WQOHdmxW_vw

WATCH BOTH

our ED152 OTA,
(built-in 2pcs of ED glass during triplet elements objective lenses)
with advanced quality 3inch dual speed focuser for astro-photography,
with black carbon fiber tube,
with ring and dovetail rail,
with aluminium case package,
USD4950

our advanced focuser is no problem when astrophotography

[wasyoungonce (Brendan)]

Sounds like an ad?

Although an interesting one. Lens cell is fully collimatable and looks like Baader steeltrack focuser, 3", R&P. Could do with better clamshell rings..like WO etc. Price is nice indeed. Very nice

Maybe the OP can answer if they have a focal reducer/flattener for this scope?

edit:

Ahh.... Scott said they have a 3" flattener in works...but has me asking...is this usable with the older 127ED?

[cventer]

Def an advert

OP also posted same thing here: http://www.telescopereviews.com/ubbt...Number/4740878

Seems like skywatcher are planning similar scope although theirs is f7.5

[wasyoungonce (Brendan)]

Although the Skywatcher is a 5 element design @F7.5 (difficult to tell as their site lists it @F7.0) using FPL53 in some elements and this is 3 elements @F8.0 using Hoya FDC-1.

We live in interesting times if one can have a 6" APO for less then $5k!

[cventer]

Whats the difference between those 2 glass types ?

ie FPL53 vs Hoya FDC-1 ?

[wasyoungonce (Brendan)]

Well fort a start...cost but they are both considered low dispersion or Extra Low Dispersion Glass (ED Glass).

FCD-1 (sometimes called FPL-51) is a lot cheaper than FPL-53 and I think easier to cast blanks, especially large ones.

FPL-53 is probably considered better in chroma correction but FCD-1 is not bad. Actually ....I should say FPL-53 bends light differently compared to FPL-51.

Consider most APOs have one element of ED glass the other elements are another glass. Although from what I have read, in the case of this Skywatcher, they talk of more than one element being FPL-53 (ED glass). This is probably due to the Petzval type design so it should have very good colour correction.

As for which is better....probably the 9 pages on CN is best to read....boils down to what suits your wallet (edit: and the abilities of the designer and quality of manufacture).

[gregbradley]

The TEC160ED used FPL51.

I never read any complaints about that scope's peformance.

Greg.

[bratislav (Bratislav)]

It is not the ED glass what makes the correction. It is the choice of mating glass (or glasses in case of triplet). FPL53 allows for a better color correction and spherochromatism control, as it has significantly higher dispersion than FPL51. But ultimately is the other two types around it that will make the difference (or not).