Explore Scientific vs Long Perng Triplet Apo

[Blake]

First of all I hope everyone's had a good Christmas and New Year!

I'm just after some opinions/experiences with Explore Scientific (made by North Group as far as I can find) vs Long Perng 127mm/126mm Triplet Apos (or any of their refractors for that matter). The particular models I'm looking at can be found following these links, both for around the $3000 mark.

http://astroshop.com.au/products/details.asp?id=MAS-048B
http://www.andrewscom.com.au/site-section-10.htm

I've heard some reports of bloated stars among other things, but being triplet apos I'm a bit doubtful of how exaggerated any problems really are and whether they are common problems or problems with older models. There doesn't seem to be a huge amount of info out there.

Anyway, what's your thoughts? :)

[brian nordstrom]

:) Hi Blake , I don't think you will go wrong with either and having owned a 127mm NG triplet and 90mm LP APO in the past can say that I seen no 'Star Bloating' in the NG 127mm it had beautiful optics .
In my opinion the LP had better build quality , more solid and better fit and finish , but the NG had the better optics ( again in my opinion ) so if you get either one you wont go wrong as both Andrews and Astro Shop have good return policies .

Both very good scopes for the price , but if I had to spend your money :lol: , I would go the LP because of its better build .

The focuser on my NG was to be honest really horrible ! , I replaced it with a FT ( VERY EXPENSIVE ) ,that was its main down fall and unless the newer ones are drastically better be ready for an up-grade if you go this way .

Both came with a nice alloy case .

The NG came with a diagonal , finder and rings , the LP none .

My 5c worth .
Brian.


ps. I have a nice IEQ45 mount that would suit either very well ;) .

[David Niven]

Hi Blake,

I have the NG 127 triplet purchased from VTI Optics.
They were selling it for $1299 then and a great value.
I am happy with the optics which is good and have since added a WO crayford focuser. The original focuser is useable for visual but the WO focuser is much better!

[casstony]

The Long Perng is likely the better scope using more expensive glass (giving a more color pure image) and it has a better focuser - since both scopes cost $3000 it's the one I'd consider first. Long Perng also seems to have better quality control standards.

I purchased one of the North Group ED127's that David refers to - not a bad scope but certainly not finished to the standard I'd expect of a LP or William Optics scope. The first objective came with a certificate indicating it was about 1/4 wave pv (which is ok) but was exchanged due to a long, shallow scrape in the coatings. The replacement objective wasn't accompanied with a certificate but is better figured with an excellent star test.

[Blake]

Thanks for the replies, it's much appreciated! :D


I'll keep that in mind Brian ;)



Would that be this one here (http://www.vtioptics.com.au/sold-out-north-groups-hioptics-ed127-f-7-5-triplet-apo-refractor-the-ota-comes-with-a-dual-speed-crayford-focuser-a-2-ins-dielectric-diagonal-a-8-x50-viewfinder-and-a-delux-lockable-aluminium-case-just-1599-delivered-email-to-inquire/)?

I had a bit more of a look in to the scopes after hearing about the cheaper price from VTI Optics, and did a rough bit of a comparison below.

Basically, it appears that the sold out North Group and the Explore Scientific apos are pretty well identical, the only difference being fit and finish, OTA material, and possibly a couple of accessories. The Explore Scientific costs twice as much as the North Group, but it is a carbon fiber tube (pricey) which halves the weight and effectively means that the scope + camera + accessories could be mounted on say a SkyWatcher AZ-EQ6 GT Mount with ease, saving the $2500 step up to an EQ8 (Not saying the mount should be skimped on!!).

So although the Explore Scientific scope may cost $1500 more than the heavier North Group scope, some money might be saved by not needing to step up the mount required. More savings = more accessories ;) (This theory also applies to the Long Perng scope)

Now, the Long Perng apo looks to be completely different to the North Group/Explore Scientific scopes. I'm not sure if this scope is sold under another brand name to compare prices to. As Tony mentioned, the glass quality does look to be better, as does the focuser and build quality. So I'm leaning towards the Long Perng scope of these choices (if my reasoning is sound).

North Group 127mm Triplet Apo (Sold Out) - $1499

- Aperture: 127mm
- Focal Length: 952mm
- Focal Ratio: f/7.5
- Glass Type: FCD1 ED Glass
- Focuser: 2" Dual speed, 10:1 Crayford focuser
- OTA Weight: 10kg

Accessories Included:
- 2" star diagonal with 1.25" adapter
- 8x50 straight through finder scope with illuminated reticules
- Ring and dove tail rails
- Dew shield and end caps
- Lockable, padded, aluminum storage case

Explore Scientific 127mm Triplet Apo (Carbon Fiber) - $3185

- Aperture: 127mm
- Focal Length: 952mm
- Focal Ratio: f/7.5
- Glass Type: Hoya FCD1 ED Glass
- Focuser: 2" Dual speed, 10:1 Crayford focuser
- OTA Weight: 5kg

Accessories Included:
- 2" star diagonal with 1.25" adapter
- Right angle finder scope with illuminated reticules
- Ring and dove tail rails
- Heavy duty twist lock carry case
- Extened-life-of-the-product warranty

Long Perng 126mm Triplet Apo (Carbon Fiber) - $2999

- Aperture: 126mm
- Focal Length: 880mm
- Focal Ration: f/7
- Glass Type: FPL-53 ED Glass
- Focuser: 3" Dual speed 11:1 Long Perng micro-focuser with 1.25" adapter
- OTA Weight: ??? (I'd guess approx. 5-6kg)

Accessories Included:
- None listed.


P.S. I should mention that I plan on imaging using my unmodified Canon EOS 6D, and I did consider a reflector for a larger aperture and more light gathering power to reduce the exposure times required to capture those Ha reds, but I'm not a huge fan of diffraction spikes and I'd rather spend more time imaging over nights or weeks than worrying about collimation. And I think considering the secondary obstruction size in fast imaging newts and RC's of around 10" aperture, the gains wouldn't really be enough to compete with a 5" refractor, but I could be wrong. And I might be a little bit lazy :lol:


Thanks again! :)

[Larryp]

Long Perng make most of the William Optics scopes:)

[Blake]

Well I haven't really heard any bad things about William Optics scopes :)

They don't look to have any models of the same size to compare unfortunately. The closest scope size wise would have to be the WO FLT 132 Triplet for $5699. The closest scope price wise is the WO Fluorostar 110 Triplet for $3199.

From what I gather, WO is considered to be a reasonably premium refractor brand, and Long Perng is more of a mid range/more affordable Chinese manufacturer by some (though there's not many things now days that aren't made in China). So what I'm trying to say is;

Is $3000 too much for a Long Perng Triplet, and would it be a better choice going for a smaller WO or a much smaller TeleVue refractor for the same price? Is image quality going to improve that drastically with a small TeleVue, that it will justify the 40mm loss in aperture?

Resale might be better for a TeleVue, but if it's a small scope I doubt I'd ever sell it, rather use it as a guide scope or something.

[casstony]

Just to confuse you a little more Blake :) I though I'd mention a couple more scopes since you're considering spending $3000.
One is the Takahashi FC100D which can be found new at the Takahashi Australia advert on the side of this page ($2350).
The other is a Takahashi FS128 in immaculate condition being sold by IIS member Ian Fry - He's got it advertised on 'Australia Astronomy Buy & Sell' for $3700 http://www.astrobuysell.com/au/propview.php?view=2406

The FS128 is not a heavy scope but it is reasonably long at f/8, while the FC100D is a new model and it's very light and portable.

[Larryp]

Another brand to consider is Stellarvue. They make really excellent refractors-I have owned 2 of them and they were both superb mechanically and optically.
You do need to buy direct from the manufacturer in USA, but that is no problem as their customer service is top notch.

[David Niven]

Yes, that's the one on VTI Optics.
Long Perng $2999, WO Fluorostar 110 $3199, FS 128 $3700, FC100D for $2399?
I would find the extra $700 and buy the FS128 among the three for visual use and the FC100D for astrophoto!

[brian nordstrom]

:) Blake have you given any thought to the SW120ed ? these use FPL53 in the lense and get rave reviews every where and are only $2299 at Andrews .
There are a few reviews comparing these to the triplet 127mm's out there and most prefer these over the triplets for many reasons .
Just a thought and you will save about $1000 for other goodies .
Brian.

[JohnH]

I had a NG 127 - and the focuser was not up to AP useage - I replaced it with a moonlite. With the mono CCD I was using I found had to change focus for the BLUE filter for best results - with a colour DSLR you will not be a able to do this. So if you adjust for "sharpest" focus you will get blue halos - a tweak to defocus (inwards iirc) slightly will get all the colours together. This results is a very slightly softer image - but looks much better. That is the only issue I had beside the focuser and may be the reason some report bloat.