APO Doublets Passe'?

I've been away from Astromart for awhile and, on returning, see that the refractor market has changed. It appears, from watching the classifieds, that APO doublets are no longer the rage. TV102s and FS128s appear infrequently and languish on the listing when they do. When they do sell, they go for well below what was paid. All the attention & activity now seems directed toward triplet and Petzval designs.

Is this because the doublets are now a known quantity to the 'observer' part of the astro community and the curiousity basis for buying is gone or is it because the 'trader' part of the community has moved on to the latest and greatest? Whichever is true, it seems the real demand for these scopes is (and possibly always was) rather shallow.

I'm aware the doublets will show color if not perfectly focused. I've seen a small amount from time to time with my TV102, even less in my FS78; still the doublets are light and easily managed compared to such scopes as the TOA130.

A 5" APO would be the next logical step for me, but not if it means buying a G11 to support it....the GM8 is enough of a hassle. A minty FS128 would be ideal, but they rarely appear anymore. And then there's the hit involved with selling the TV102....

It seems that an APO as an investment is somewhat like stocks or playing poker...you gotta know when to hold 'em and know when to fold 'em.
Bob

I am very happy with my 127 ED Meade APO doublet (Semi-APO to be sure not a true APO), little color, great images and can take a lot of power. The price is very good too. A good 5" scope for a good price. They come up from time to time and the price is always good. Mine came with the LXD650 mount, which has worked well so far. I have only done visual with it, no photography yet.

I sold an FS128 within the last year for 95% of new price. Now that they're out of production I wouldn't understimate their resale value.

> I'm aware the doublets will show color if not perfectly focused.

Many will show color all the time, focused or not. Put a TMB, TEC, or AP APO triplet, or a Tak FSQ, next to your TV102, point both at the moon, and step back. Look at the glowing exit pupils of the eyepieces. One is yellow. One is white. Showing color isn't necessarily a purple cloud but the overall color balance of the view as well.

The TV102s do take a significant hit on resale, like the FS102's, but the FS128s (in good condition) sell for near new prices with mild patience. TMB can take a beating on price as well, I bought a TMB100/8 for $1650 once.

I havent held a TOA but it sounds like Tak ditched their nice lightweight tubes from what I hear. An FS128 would be deluxe on your GM8 and I would highly recommend one based on my own experiences with the one I had.

Passe' or not, I have always been sufficiently impressed enough with the Tak doublets that I just sent payment to an Astromarter for what I consider a very good deal on an FS128. Not sure I want to compare it to an AP or TMB triplet, but I am pretty sure that I am going to be pretty happy with it.

Doug
Midway, FL

Is this because the doublets are now a known quantity to the 'observer' part of the astro community and the curiousity basis for buying is gone or is it because the 'trader' part of the community has moved on to the latest and greatest? Bob

I think theres two effects. The Chinese are producing good
APO doublets now in sizes up to 120mm at roughly one-third
to one-half the price of comparable goods a few years ago.
For example an Orion ED-80 at $499 vs. a TV-85 at
$1750 (optical quality roughly identical, mechanics a
little better in TV).

Other effect is availability of triplets. Not so long
ago there were mainly two sources -- AP with a 5 year
wait, and Takahashi at an astronomical price. Now
the market is flooded with superb TMB triplets, and
Tak has come down to reasonable prices on triplets
-- both are available off the shelf.

Hi Bob.

The FS 128 is a great scope. I have one on a GM8, not an ideal mount for the Tak; a bit wobbly when trying to focus at higher powers. But it tracks very well. Another scope you may want to consider (if you have the money) is the TEC 140. I believe it's only 2 or 3 lbs. heavier than the FS 128 (so should behave similarly on the GM8), has a focuser second to none, has a collapsible dew shield, making it about 3 ft vs. the Tak's 44 in. or so, and it will give you that extra 12mm of reach.

Steve O.