StellaLyra 6" CC first impressions.

[Louis D]

The only Chinese/Taiwanese made focuser I really like came with my KUO 152mm achromat.  It doesn't slip under heavy loads, it has a hefty feel to the focusing action, there's no sponginess or notchiness to fine focus wheel, etc.  I wish they sold it separately.  The only thing it needs redesigned is the focuser rotator which grinds, grabs, and feels loose until completely locked down tight.

The GSO focuser that came with my 6" f/5 Newt is borderline awful.  Set the tension too high, and it won't move.  Set too low, and the draw tube drops down by itself under load.  The fine focus is good on it, though.

The focuser that came with my Astro-Tech 72ED slips like crazy under any load above one pound.  The fine focus is good on it, however.

The focuser that came with my TS-Optics 90mm Triplet APO (likely Sharpstar made) has a spongy feel to the fine focuser, along with considerable backlash in its action.  It will also unwind under heavy load despite having a helical R&P.  It will literally spin the focuser wheels while doing this.  A properly designed helical R&P won't do this.  To combat this, I have to keep a certain amount of drag on the pinion tension screw which messes with fine focus.

[Mr Spock]

Eeek. CA and SA on the finder are nasty. It's even noticeable at x10 with the 22mm LVW. Very disappointing. It will find things though which is all I need it to do.

Had a look through the CC at some brighter stars. Diffraction spikes are very prominent on Arcturus. With Algieba I can see them on the primary, but not on the secondary. As I've been looking at stars mag 6 to 10 that explains why I don't see them. As that is what I'm looking at they are not relevant.

So, with out further ado, I can get on with using it for observing. I'll decide whether or not I can tolerate the focuser later.

[Mr Spock]

Verdict on double stars. It's a nice scope, but, Σ1643 (9.03 + 9.45, 2.7") and Σ1639 (6.74 + 7.83, 1.8") are actually easier in the FC-100...

So there we go. I'll most likely sell it on. I suppose it's a bit optimistic to expect a £439 scope to match a £3k+ scope.

[IB20]

I can’t say I’m overly surprised by this. I’ve found similarly in comparing an 8” to smaller refractors. I guess if the seeing was absolutely perfect it’d be different but how frequently do we get blessed with that in the UK?!

[Mr Spock]

Seeing was fine. Comparing the two, the apo had much tighter stars with no diffraction rings, so the larger aperture had no advantage. I'd wanted something that would make the stars look brighter due to my light pollution. In practise it doesn't happen, simply because the apo is several levels better optically. There's nothing wrong with the CC, and it's performance is on a par with other mirror systems; it's just not like the Tak!

[LondonNeil]

Interesting and honest review.  I

It does seem counter intuitive for 7" of aperture to turn out worse than 4" but then again, very intuitive that £439 can't match £3k.  

How would the CC compare to a similar priced frac?  Is there a refractor in that price range?  A large achromat or a small ED I guess.

[Mr Spock]

19 minutes ago, LondonNeil said:

How would the CC compare to a similar priced frac?  Is there a refractor in that price range?  A large achromat or a small ED I guess.

An achromat would be very poor compared to the CC. The only way to get a better performance at the price optically would be an 8" Dob. A small ED, such as an 80mm, wouldn't be as good. I have one lying around and it can't get up to the x230 the CC can.

I'm comparing the CC with one of the best apos made. It isn't a fair comparison!

[dweller25]

48 minutes ago, LondonNeil said:

Interesting and honest review.  I

It does seem counter intuitive for 7" of aperture to turn out worse than 4" but then again, very intuitive that £439 can't match £3k.  

How would the CC compare to a similar priced frac?  Is there a refractor in that price range?  A large achromat or a small ED I guess.

I think MrSpock has the CC 6” version ?

I had the TS version but it had an effective working aperture of 140mm which meant the secondary obstruction was 42% !

It was no match for my 4” F/8 refractor, which is a shame as I liked the form factor.

Edited June 1 by dweller25

[Greymouser]

16 minutes ago, dweller25 said:

I think MrSpock has the CC 6” version ?

I had the same but it had an effective working aperture of 140mm which meant the secondary obstruction was 42% !

It was no match for my 4” F/8 refractor, which is a shame as I liked the form factor.

Completely agree. I have the TS version of the 6" CC, whilst very good, it is beaten in all ways by my F13.2  4" Bresser, which is also cheaper. Just as easy to mount as well, without any CA. I would even choose that over the 4" Starfield which I had for a while.

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-ar-102l-1350-refractor-ota.html

[LondonNeil]

2 hours ago, Mr Spock said:

I'm comparing the CC with one of the best apos made. It isn't a fair comparison!

Exactly, I see that,  but it was interesting to try and see how extra aperture might make up for it's comparative failings, especially in the areas you wanted due to light pollution. 

[bosun21]

I also bought and sold a 6" CC for the same reasons highlighted above. This time I bought the 180 Maksutov which is proving to be very good on doubles with very near apo refractor performance. The small CO contributes to this I'm sure as well as good contrast.