Apo refractors comparison

Hi all,

I'm going back and forth on a refractor purchase and would like some advice. So far I've owned reflectors (currently a 12.5" home made truss Dob with a Zambuto mirror, and SCT's (C-8, 10" LX200).

I'd like to supplement my armamentarium (ie, buy more stuff) with a decent refractor. I'm looking at the 80mm WO Megrez IIED, a used Tak FS78, and an Orion 80ED. My question is this: the WO and Tak are roughly twice the cost of the Orion. I know the WO and Tak mechanicals and build quality are better, but are the eyepiece views significantly better to justify 2x the price?

I've never used a Tak but have heard the passion of Tak owners and seen lots of beautiful images, so I'm leaning that way (actually I was surprised to find that an FS78 OTA is now going for well ubder $1000). I just wanted to get a sanity check before I click "Pay". Thanks,

Tim Iafolla

Since I own a Takahashi FS 78 I think I would go for it over the list of options you mentioned. The Tak is more than likely to have been figured to a much higher standard then either of the before mentioned scopes. My own experience for this particular scope the views of the moon and planets are 2nd to none. Actually the scope behaves more like a 4 inch refractor from what I can tell and from what others who have looked thought my little Tak would agree with. Also the Tak FS 78 is a real charmer for a quick setup double star observing scope. I use my FS 78 in tandem with my AP 130 F6 and both scopes compliment each other quite well.

Clear Skies
Dwight L Bogan

Having used the Orion ED-80 (which I own) and Tak FS-102
(do not own) I would say the difference will become apparent
at very high powers. The Tak will show a little less false
color on double stars, moon, and planets. But it is
subtle and an inexperienced observer might not notice
the difference. If you are just using it for casual observing
it would be fine, but if you like pushing your equipment to
the limits to see what it can do, you might like the Tak
better.

Also if you envision imaging, the focusser on the Tak is
probably a better choice. The one on the Orion tends to
slip if you put very heavy loads (2 - 3 lbs) on it and point
straight up. There are after-market replacement focussers
for the Orion, but this will quickly erode the price
advantage.

I have formerly owned one Tak FS-102 and two WO Megrez 80 scopes (I currently have the ED Triplet). I have seen Orion ED 80 scopes at star parties. My humble opinion is that if quality...both optical and mechanical...is important, the Tak will be the scope to buy. Its fit and finish are excellent and I personally have not seen a Takahashi that didn't put up first class images at the eyepiece. Second, I would nominate the WO Megrez 80 ED Triplet. It will equal the Orion optically, and it is superior mechanically with its smooth, rotating focuser with a two speed option (or it may be standard by now, I'm not sure) and retractable dew shield. Again, fit and finish are very good, although not quite up to the standards of Takahashi, but close. The Orion is an impressive scope for the money, however. It has fine optics but from my experience its construction quality isn't quite up to the standards of either Tak or WO. Retrofitting the Orion with after market focusers has become fairly common, from accounts I have read. On the other hand, Orion's ED 80 is very attractively priced, making its modification seem cost effective to many owners.

Other scopes worth looking into would be the Stellarvue and Televue scopes. Both are fine optically and mechanically.

Hi,

The only one I can comment on is my Megrez 80 that is now an APO with the APOGRADE.

See my review if you are interested...
http://www.astromart.com/articles/article.asp?article_id=398

Timm

Thanks to everyone who replied, good comments all. I've decided to go with the 80ED, mainly because I already have a scope that is excellent at high power (12.5" F/6 ZOC mirror). I will be using the refractor mostly for wide-field shots rather than pushing the power up high.

This was a difficult decision because I'm a gadget guy (aren't we all) and I appreciate intrinsic value in high-quality and elegant mechanicals. But in this case I can buy a Nagler with the difference! 8)

Thanks again,

Tim Iafolla

Hi Tim. Currently I have a Televue Pronto, Takahashi FS-78, Orion 100 ED, Meade 127ED, and D&G 5" f/10 refractors. The Takahashi has the sharpest images of the lot, though not by much. Were the decision mine I would opt for the Orion 100 ED over the FS-78 or 80 ED. The price for a new 100 ED is about the same as the price for a used FS-78, and it has over 50% more light grasp. It is also extremely lightweight for a 4" scope coming in at just 7 pounds. For reference the Orion 80 ED comes in at 6.5 pounds. It's no harder to mount than the any of the 3 inchers, has a nice f/9 focal ratio and 900mm focal length so it can go wide or high as you wish. The extra inch of aperature makes a huge difference in terms of handling magnification, showing dimmer stars and pulling in subtle details on the moon and planets. Also, 4" of unobstructed aperature is where deep sky just starts to get interesting. The fuzzy blur of M10 in the FS-78 starts to show distinct resolution in the 100 ED.

Just wanted to tthank you all again for your advice. I ended up getting the ED80 and thought an udate was in order.

Obviously I can't compare it side by side with the FS78 I was also considering, but here are my impressions: overall, these 80mm Chinese scopes have to be the deal of the century, at least in terms of optics.

The mechanicals are OK: the Crayford is definitely budget level, but was improved with some tweaking. It's fine for visual use, but for photography I will probably add a 2-speed upgrade with a compression ring holder.

The tube is a little bulky, because I think it's shared with some other scopes. It looks well baffled and is very dull black inside. The dew shield and dust cap are good quality and both have the right amount of friction holding them on (which is more rare than you would think for such an easy concept).

For visual use I have a WO 2" diagonal. My EP's are decent but nothing fancy: 2" GSO wide-fields for the longer f.l.'s, Televue plossl's for the 15mm to 32mm range, and Orion Lanthanum ED's for the 2.8mm to 12.5 mm range.

The past several nights have been nice and transparent but the seeing was atrocious. Last night it settled down nicely to 6 or 7/10 (which is about as good as Maryland gets). Star test at 214x (2.8mm EP) showed nice round diffraction rings, almost identical in and out of focus (maybe a touch overcorrected, no worse than 1/5 or 1/6 wave). Collimation is spot-on, and no sign of pinching.

Wide-field views are lovely: pinpoint stars with no CA, and the natural colors showing well. Too much light pollution to get a real reading on DSO's, so I turned to Saturn and cranked up the power. I won't belabor the details. Suffice it to say that this scope stood up to stupid-high power without breaking down. 50x/inch was easy, 70x/inch would have been fine if I had been using a better mount. I could watch the atmosphere move the image details around, but periodically they would snap in sharp focus so the optics were still working well at that power. No hint of any CA or halo.

Anyway, I'm perfectly happy with my choice and feel like it's an excellent value. Thanks again for the help picking it out.

Tim Iafolla