TheSkySearchers

I like were this discussion is going. Hand figured doublets and triplets come at premium. Most of us are looking at mass-produced scopes in particular in larger aperture.

At one point I had a choice between similarly priced ES 127mm APO triplet and SW 120mm ED doublet. My understanding is that the larger scope gets the harder is to get the same level of CA correction in a doublet compared to triplet. So, I went with ES, because it was triplet, had larger aperture (hey, every mm counts! ) and I knew that I can rely on ES customer service if there will be any issues.

I was very happy with ES 127mm performance. I don't believe I saw as sharply defined airy disks in my other fracs which all happened to be doublets. It could be just seeing, I did not do comparison on the same night, also the aperture sizes are different. But we are talking about cumulative experience based on multiple sessions. At one point I had ES 102mm triplet and now have Stellarvue 102mm doublet. I don't believe I ever saw Jupiter as sharply defined in SV compared to ES, but the color saturation seems better in SV (the colors could be because of upgraded diagonal). Again apples to oranges, different nights. Maybe higher position of Jupiter.

I did not think of it much until I read Jones comments, which seem to match my experience.

I have only heard good reports from APM 140 users. Color correction is a bit better than their 152 ED Apo, which I have. I see no noticeable false color from my 152 at any magnification. If I go to extremes I can coax some out though, so it really is fully Apo visually IMO. And on planets, which is my primary passion, it is superb. Like any telescope if you want the top performance then it needs to be precisely collimated and thoroughly acclimated. Once that is achieved with the 152 it is a stunning planetary performer, so the 140 should be just as good.

IMO, a triplet is overkill for visual and simply not worth it when the doublet is well color corrected, like the APM 140 and 152. But cool down with a 152 can take some time, so when I go out into very cold temps then it can take a full 2 hours. If I am doing planetary I never wait less than 1 hour. The 140 should cool faster though.

I have had about 40 refractors over the past 20 years.
And the ones I've kept are all triples, all visual use, all China made lenses, sourced from APM and Teleskop Service.
90mm f6.7
107mm f6.5
115MM F7
130MM F7
They give nearly the best planetary views you can buy without going too crazy price wise. Maybe the latest crop of doubles can match them. All doubles from the past cannot except a few with big price tags.

Probably build one of those 125mm f8 doubles next. The one from TS Optics weighs 16 pounds. I can usually save 25% in weight the way I build ota's. So about 12 pounds total. Should work great on the Stellarvue M2 mount. Have been looking for the maximum scope to ride on an M2. The 115mm runs well on it. The 125 will be a little lighter but longer. On refractors every 10mm diameter increase counts.

Lady Fraktor wrote: ↑Fri Jun 04, 2021 6:04 pm You seem to be comparing mass produced to premium optics which you just cannot do.

Mass produced optics will only have a standard of QC at a set price point, where a premium optic QC level will be much higher.

Occasionally you will find a Meade, Skywatcher, Celestron that is better than the rest of their offerings but it is priced accordingly as well.
Those few telescopes get a higher QC level than the rest.
An example is some of the high end Skywatcher that were designed in Belgium (Lichtenknecker Optics), not in China.

Is that the Esprits?

Esprit, Evostar I guess it depends on the area you purchase it in.

Lady Fraktor wrote: ↑Sun Jun 13, 2021 6:47 pm Esprit, Evostar I guess it depends on the area you purchase it in.

Esprits are triplets & Evostars doublets. There were early collimation issues with Esprits (& other makes) I think, it was one of the reasons I bought a Takahashi TSA-120 triplet instead, never any reported issues & only good reviews.

25585 wrote: ↑Wed Jun 02, 2021 6:31 pm Been in my subconscious tempting me. (...)
https://www.cloudynights.com/articles/c ... 20portable.

After reading the review I can imagine your subconscious temptations. The same happened to me.
It's a doublet, beware!
After reading this discussion so far I would say go for it!
I haven't seen it on the APM site yet. Is there already a price known?

John Baars wrote: ↑Wed Jun 30, 2021 9:40 pm

After reading the review I can imagine your subconscious temptations. The same happened to me.
It's a doublet, beware!
After reading this discussion so far I would say go for it!
I haven't seen it on the APM site yet. Is there already a price known?
[/quote]

It is on the APM website - https://www.apm-telescopes.de/en/telesc ... -tube.html

For US buyers on the Lunt site - https://luntsolarsystems.com/shop/apm/a ... ical-tube/

I doubt there is any visible CA on it as I have the APM 152 ED Doublet and the only thing I get a very very slight purple fringe on is Sirius. Everything else nada. And the color correction on the 140 is slightly better due to the use of FPL-53. Only thing I do not particularly like about the 140 is that for economies they used the same tube as the 152. So same girth as a 152, just shorter. Would have been nice if they slimmed the tube to 140. Otherwise have heard nothing but good reports. I am very pleased with my 152.

WilliamPaolini wrote: ↑Wed Jun 30, 2021 9:58 pm

John Baars wrote: ↑Wed Jun 30, 2021 9:40 pm

After reading the review I can imagine your subconscious temptations. The same happened to me.
It's a doublet, beware!
After reading this discussion so far I would say go for it!
I haven't seen it on the APM site yet. Is there already a price known?

It is on the APM website - https://www.apm-telescopes.de/en/telesc ... -tube.html

For US buyers on the Lunt site - https://luntsolarsystems.com/shop/apm/a ... ical-tube/

I doubt there is any visible CA on it as I have the APM 152 ED Doublet and the only thing I get a very very slight purple fringe on is Sirius. Everything else nada. And the color correction on the 140 is slightly better due to the use of FPL-53. Only thing I do not particularly like about the 140 is that for economies they used the same tube as the 152. So same girth as a 152, just shorter. Would have been nice if they slimmed the tube to 140. Otherwise have heard nothing but good reports. I am very pleased with my 152.
[/quote]

Tak FS refractors had larger bore tubes, so the APM is in good company. Bigger focusers are easier to provide, thinking of my grenade eyepieces etc.