Small ED/APO refractors - what are the options?

[Retrograde (Pete)]

Hi all,

I'm thinking of purchasing a small ED/APO refractor and wondered about the pros and cons of different models. I'd prefer something below 80mm and it would do multiple duties as:

small 'grab & go'
wide-field imager
guidescope
portable eclipse rig
and possibly even as an over-sized finderscope.

So what are the pros & cons of these options?
Tak FSC60, WO Zenithstar 71, Stellarvue SV060EDS - any others worth considering?

Thanks in advance,
Pete

[glend (Glen)]

Have a look at the Explore Scientific ED80 APO Triplet. I have one and the quality is great for the price, and they are on sale at Opt Corp right now for $680 USD for the white tube Essential model - so you can probably get one for less than the GST threashold. Of course if cost doesn't mean anything to you and you want to buy a Tak then do that, but the ES will do all the things you listed and give you greater aperture than those you listed.

[Slawomir (Suavi)]

Hi Pete,

I have also been wondering about quality wide field scope- so will watch this thread with interest.

I would also consider quality of the focuser, unless you are keen to upgrade the stock one. Poorly attached flexing focuser will spoil imaging sessions much more than not too perfect optics. I would like to think that Tak and Stellarvue would make reliable telescopes.

[Meru (Michael)]

Hi Pete,

I used to own a AT65EDQ - it was a fantastic scope and the specs/price were amazing, always regretted selling it. Borg also have a range of scopes under 80mm but are pretty expensive.

[Retrograde (Pete)]

Originally Posted by glend

Have a look at the Explore Scientific ED80 APO Triplet.

Thanks Glen - 80mm is really a bit bigger than I wanted to go. I already have an ED102 triplet for more aperture (& focal length) if I need it.

Originally Posted by Slawomir

I would also consider quality of the focuser, unless you are keen to upgrade the stock one.

Thanks Slawomir good point. I upgraded the stock focuser on my ED102 so not keen to do it again on a smaller scope.

Originally Posted by Meru

I used to own a AT65EDQ - it was a fantastic scope and the specs/price were amazing, always regretted selling it. Borg also have a range of scopes under 80mm but are pretty expensive.

The AT65EDQ sounds like another worthwhile option - I've heard of it but don't know much about it so thanks for mentioning it. I've heard Borg are expensive but have a good reputation - not sure where to source one from though.

[N1 (Mirko)]

Originally Posted by Retrograde

I've heard Borg are expensive but have a good reputation - not sure where to source one from though.

http://www.hutech.com/

If cost is not the main concern, the FS60 probably won't disappoint. Especially the grab-and-go and eclipse bits it will do superbly. The OTA is very small and light. And for those times when you want a little bit more reach, you can attach an FC76 objective unit, which has been offered second hand on this forum. The resulting 3" f/7.5 ist still highly portable when broken down, but not quite as wide-fieldy, especially when retaining the 1.25" setup.

[blink138 (Pat)]

flash has a 60mm sharpstar fpl-53 doublet for sale on iis classifieds at the moment!
pat

[LewisM]

I was going to say what Pat said. I have personally looked through the EXACT scope on sale, and it was surprisingly good! I mean, REALLY good - rich view with good contrast when coupled to a good eyepiece.

Be perfect for terrestrial and WIDEFIELD astro. And well priced from Flash too.

[Profiler (Profiler)]

If you are considering a Tak FS-60 then you should also consider the Televue TV-60. Optically at 60mm there isn't anything between them irrespective of whether one is genuine fluorite vs FPL and given you want it for G&G etc something that is more robust than fluorite is probably better. The Tak can 'in theory' accept 2' EPs with appropriate adapters but in reality is totally impractical in such a configuration and is hopelessly out of balance for any serious observing when using 2' EPs. Instead, you will only be using 1.25 EPs which puts it back on par with the TV-60. Televue also make a specialised adpater which allows the TV-60 to be used as a finder which is fully adjustable and will fit any telescope. As far as portability there is nothing that genuinely competes with the TV-60 - you can literally carry it in your coat pocket. Although there are certainly small refractors around a traditional R&P (or any horizontal etc) focuser is a liability for portability as it can potentially be damaged whereas the TV-60 features a clever 2 speed helical focuser design which can't be snagged and thus damaged whilst on the move unlike all others.

[Camelopardalis (Dunk)]

I bought a Zenithstar 71 for grab and go a few years ago, it's well built and has nice optics. It's travelled with me to 4 continents at this point does a decent job of Jupiter at >100x, nice and crisp for open clusters, even resolves some stars in Omega Centauri. When used with a long focal length eyepiece it has swallowed Magellanic Clouds whole It has a decent rack and pinion focuser too, easy holds a hefty 2" diagonal and quality big eyepiece.

For the past year it's also served as my imaging scope, as it's nice and fast at f/4.7 with the reducer/flattener, although as it's only a doublet there's a little blue halo effect on long exposures of bright stars, which can be edited out in post for the most part.

[Profiler (Profiler)]

Excluding cost as a variable the TV-60 coupled with a 1.25 everbrite and 2-4mm Nagler Zoom set at 2.5fl will easily reach 144x magnification and give a sharp, bright image of Saturn with Cassini plainly visible and doesn't require exceptional conditions to achieve such results.

I must however stress that to achieve these results does come at a disproportionate cost

[Retrograde (Pete)]

Thanks for all the great information guys.

Originally Posted by N1

http://www.hutech.com/

If cost is not the main concern, the FS60 probably won't disappoint.

Thanks Mirko. The main thing that puts me off Tak is the cost of accessories etc. I've never owned a Tak (or even looked through one ) so would have to collect flattener & anything else I'd need from scratch (although I'd still need a flattener for the other options).

Originally Posted by blink138

flash has a 60mm sharpstar fpl-53 doublet for sale on iis classifieds at the moment!
pat

Originally Posted by LewisM

I was going to say what Pat said. I have personally looked through the EXACT scope on sale, and it was surprisingly good! I mean, REALLY good - rich view with good contrast when coupled to a good eyepiece.

Thanks for the heads-up guys.
From a brief search it seems that Sharpstar provide donor telescopes for Stellarvue & this model should be functionally identical to the SV60EDS?
I understand Stellarvue provide added value with QC & warranty-support etc (although luckily we have Lewis in this case ).

At 330mm it's a bit shorter than I'd ideally like & for photography it's FOV would be similar to lenses I already own (although likely would give better results at that FOV)

Originally Posted by Profiler

If you are considering a Tak FS-60 then you should also consider the Televue TV-60. ........

The Tak can 'in theory' accept 2' EPs with appropriate adapters but in reality is totally impractical in such a configuration...........

the TV-60 features a clever 2 speed helical focuser design which can't be snagged and thus damaged whilst on the move unlike all others.

Good info thanks Profiler. I wondered about the TV60 (& also the TV76). I'm quite happy using 1.25"eyepieces with it & already have a good diagonal that size.
Is the helical focuser a real option with a DSLR + flattener?

Originally Posted by Camelopardalis

I bought a Zenithstar 71 for grab and go a few years ago, it's well built and has nice optics.

For the past year it's also served as my imaging scope, as it's nice and fast at f/4.7 with the reducer/flattener, although as it's only a doublet there's a little blue halo effect on long exposures of bright stars, which can be edited out in post for the most part.

Cheers Dunk - the WO seems like an attractive option. I can get one with reducer/flattener landed for under $1k. I've seen some shots with it & some do exhibit the blue halos though. I guess most people do a little star reduction on their images anyway so fixing halos isn't a huge extra step (however I'm just not very good at it yet).

[LewisM]

There is always the relatively new Vixen ED70SS - seems like Vixen's answer to the venerable Tak FS60.

I shot our local Vixen dealer an email asking price.

Here is an image of it: http://blogs.c.yimg.jp/res/blog-6c-d...g_0?1407119064

Looks like an FS60, only bigger, with Vixen's focuser and decals

[PlanetMan]

The mechanical design and specs which I can find online for this new Vixen ED70ss seem eerily similar to a WO Megrez 72. It's almost as if someone took a M72 and painted it plain white with a few red Vixen stickers and their stock R&P focuser

[Camelopardalis (Dunk)]

Originally Posted by Retrograde

Cheers Dunk - the WO seems like an attractive option. I can get one with reducer/flattener landed for under $1k. I've seen some shots with it & some do exhibit the blue halos though. I guess most people do a little star reduction on their images anyway so fixing halos isn't a huge extra step (however I'm just not very good at it yet).

Yeah it's not a bad scope for the money, although if I was buying again now purely for imaging I'd probably stretchy the piggy bank a bit more and go for the GTF81 or [swoon] Star71. As I said, I originally bought mine for grab-and-go/travel scope as it fits in a (padded) laptop bag.

The reducer/flattener works really well though, and is threaded for 2" filters. The halos are pretty easy to fix, once I got to grips with processing a bit

See some of my pics...

• Orion and the Running Man - beware, stretched like mad!
• Alnitak and friends - could use a repro!
• Two winter favourites - ditto above
• Surf and turf

[brian nordstrom (As avatar)]

I have owned and loved the sweet FS60 but stupidly sold it. , that scope performs way above a 60mm should. , I missed it so much and couldn't justify the 1k plus price and wanted a 60mm class scope again .
Enter the 60mm f7 Long Perng triplet from Andrews Com. and I am now the owner of truely world class small scope , this little beauty performs 98% of what the Tak did for less than 1/2 the price, built very solid with awesome ( for 60mm ) optics , its great .

I have noticed that these are not on Andrews web page but the ED 60mm doublet is and if these are as good as my triplet you can't go wrong , worth a look as they have a no question return policy . Great people to deal with.

Brian.

[MortonH]

Originally Posted by brian nordstrom

I have owned and loved the sweet FS60 but stupidly sold it. , that scope performs way above a 60mm should. , I missed it so much and couldn't justify the 1k plus price and wanted a 60mm class scope again .
Enter the 60mm f7 Long Perng triplet from Andrews Com. and I am now the owner of truely world class small scope , this little beauty performs 98% of what the Tak did for less than 1/2 the price, built very solid with awesome ( for 60mm ) optics , its great .

I have noticed that these are not on Andrews web page but the ED 60mm doublet is and if these are as good as my triplet you can't go wrong , worth a look as they have a no question return policy . Great people to deal with.

Brian.

Hey Brian,

I think you mean the 66mm ED doublet. It's the same scope as the William Optics ZS66 (and my SV66ED). Plenty of stuff on the web about the ZS66. Maybe not quite so well colour corrected as your triplet but still good.

[Wavytone]

Pete, according to your OP you already have a 102mm f/7 refractor and an 80mm f/10 Mak. To be honest it leaves me scratching my head as to why you really want another small scope than is within a factor of 2 of the aperture/focal length of scopes you already have...

[Retrograde (Pete)]

I guess that even within seemingly quite narrow sub-categories no one scope can really do it all perfectly although all the suggestions will do a reasonable job of most.

Originally Posted by Camelopardalis

if I was buying again now purely for imaging I'd probably stretchy the piggy bank a bit more and go for the GTF81 or [swoon] Star71.

Nice pics Dunk! I hadn't heard of the star 71 before but it sure sounds nice. Kind of expensive though.
Any idea about the old Megrez 72 FD? Similar to the Zenithstar colour-correction wise?

Originally Posted by Wavytone

Pete, according to your OP you already have a 102mm f/7 refractor and an 80mm f/10 Mak. To be honest it leaves me scratching my head as to why you really want another small scope than is within a factor of 2 of the aperture/focal length of scopes you already have...

The 102mm is simply too big and heavy for grab and go and way too big to take to an overseas eclipse. I did manage to drag it up to Cairns by plane but never again.
The 80mm Mak isn't exactly high-quality (it was all I could afford in 1988) or fast (f11) but it's light and easy to carry.
The next eclipse I'm planning on is the US in 2017 so there's no great hurry to buy something.
Having a good widefield astrograph might give me the chance to collect some data on M31 & the like whilst I'm over there.
Mind you I'm planning to take the family on the trip so I probably need more than just one extra scope for that trip

[Wavytone]

Ah Ok. I wouldn't bother with the small refractors - you might as well buy a pair of 70mm binoculars.

As for eclipse chasing... A whole different matter. A long time ago I had a Meade 102mm f/10 SCT with the tripod base (not the fork mount) for that purpose, a robust camera tripod was entirely adequate. IMHO it was the perfect choice - small enough to go on a plane, could be backpacked anywhere along with whatever you need, yet enough to do something reasonable.

My next choice - if you can afford it - is a Questar 3.5".