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Apm 140 VS Apm 152 for planets

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18 replies to this topic

#1 vvv

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Posted 14 March 2020 - 11:11 PM

A question to those who have enough experience, which of the two scopes will produce better detail on Moon, Jupiter and Saturn. Since 140 is fpl53 and 152 is fpl51 is there big difference? Thanks in advance!



#2 MikiSJ

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Posted 14 March 2020 - 11:26 PM

Is the APM 152 a doublet or triplet? If it is a triplet of TMB design then snap it up. It is the scope to have. I sold a Tak 152/1200 doublet to my APM/TMB 152. I kept the OTA for over a decade hoping to get another ME but situations change and I traded it last December.

APM-TMB 152 400px-2.JPG


Edited by MikiSJ, 14 March 2020 - 11:31 PM.


#3 Kunama

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Posted 14 March 2020 - 11:40 PM

The OP is referring to the APM 152 doublet not the LZOS triplet.  I think the comparison would be pretty close between the 152 and 140.



#4 vvv

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Posted 14 March 2020 - 11:41 PM

Yes i mean the doublet 152 is the 12mm difference is more essential than fpl 53 versus fpl51



#5 Carl N

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Posted 14 March 2020 - 11:58 PM

The difference in glass is made up for in triplet for doublet with those two particular scopes, imho. All else being equal for you, weight, cost, etc., take the extra aperture with the 152. My advice.

#6 MikiSJ

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Posted 15 March 2020 - 12:16 AM

As you are asking about a doublet then I would think the planetary difference would be hard to detect as seeing would be your biggest obstacle. The 12mm difference might allow you split a closer binary, but again seeing will control.

 

If cost is a factor go for the 140, if not get the 152. Then you won't have to keep answering the question, either self-imposed, or from your friends.



#7 Astrojensen

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Posted 15 March 2020 - 02:00 AM

 

 

If cost is a factor go for the 140, if not get the 152. 

They cost exactly the same. 

 

 

Clear skies!
Thomas, Denmark



#8 Erik Bakker

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Posted 15 March 2020 - 04:15 AM

Also take into consideration the difference in mount requirements. 152 will be brighter, but slower to cool down and bigger/heavier. On many nights, not even the 140mm will reach diffraction limited performance due to seeing issues.

Any fpl type will do fine in these scopes, other factors have bigger influences on the image quality at the eyepiece.



#9 Erik Bakker

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Posted 15 March 2020 - 04:19 AM

Do you have other scopes as well? Take them into consideration as well to get the best synergy.


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#10 Erik Bakker

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Posted 15 March 2020 - 04:22 AM

The physical size of a 6" apo is quite substantial, for most people 140mm provides an optimum balance between size, cost and performance, though for some the 152 works better. The better your local seeing. the smaller the temperature swings and the less travel you have to do with the scope, the more the 152 can play it's strong points. Otherwise get the 140.



#11 Astrojensen

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Posted 15 March 2020 - 05:04 AM

I can certainly attest that the APM 152 is quite sensitive to temperature drops - especially on calm, windless nights, where the inner element seems to struggle to keep up with the cooling of the front. The result is quite pronounced spherical aberration. This is made even worse if the seeing is mediocre or bad, causing lots of flaring from defocused diffraction rings around bright stars.

 

The color correction in mine is extremely good for such a relatively low priced 6" ED. It has FAR better color correction than my 80mm f/15 achromat, for example. There is only a minuscule amount of false color on the Moon at 300x - 400x.  

 

 

Clear skies!
Thomas, Denmark


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#12 Jon Isaacs

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Posted 15 March 2020 - 05:05 AM

The difference in glass is made up for in triplet for doublet with those two particular scopes, imho. All else being equal for you, weight, cost, etc., take the extra aperture with the 152. My advice.

 

They are both doublets, 

 

APM 140mm F/7 FPL-53 doublet

 

APM 152mm F/8 "Chinese FPL-51" (HK-61) doublet

 

Jon


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#13 Carl N

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Posted 15 March 2020 - 07:05 AM

They are both doublets,

APM 140mm F/7 FPL-53 doublet

APM 152mm F/8 "Chinese FPL-51" (HK-61) doublet

Jon

Well there ya go, APM has a non LZOS 152 triplet, I thought he meant that one

Edited by Carl N, 15 March 2020 - 07:06 AM.


#14 Jon Isaacs

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Posted 15 March 2020 - 08:01 AM

Well there ya go, APM has a non LZOS 152 triplet, I thought he meant that one

 

Yes.  You might have been right.

 

It's always helpful when the OP takes the time to post links so as to avoid possible confusion...

 

Jon


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#15 HydrogenAlpha

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Posted 15 March 2020 - 10:19 AM

I don't think the difference will be large, but of the two effects, I think the 12mm increase in aperture would be more significant. 

 

The 140's better colour correction would probably not lead to a noticeable change. I have observed Jupiter with an APM152 and the CA is very well controlled. 


Edited by HydrogenAlpha, 15 March 2020 - 10:20 AM.


#16 ris242

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Posted 15 March 2020 - 06:56 PM

I think the obvious difference between the 2 scopes, isn't the 12mm difference in aperture, its the 140 vs 152 focal length 980mm vs 1200mm

Looking at Jupiter it will be 20% bigger in the 152mm for the same size eyepiece.

 

If you can swing a 1200mm scope, you'd be better off with it, over the 140mm.


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#17 Kunama

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Posted 15 March 2020 - 07:32 PM

Well there ya go, APM has a non LZOS 152 triplet, I thought he meant that one

 

What is an APM non-LZOS 152 triplet?



#18 aa6ww

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Posted 15 March 2020 - 08:49 PM

What maters here is F/7 vs F/8. How many times do we see these same questions asked without people taking into consideration focal length. 

Glass types is only one consideration. Focal length is the other. 

Regarding planetary performance, neither is a great planetary scope unless these are the largest apertures you have, then you just pick the largest aperture.

There's only  a weight difference of about 2 pounds between the two scopes.  

 

..Ralph


Edited by aa6ww, 15 March 2020 - 08:51 PM.


#19 Carl N

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Posted 17 March 2020 - 10:29 AM

What is an APM non-LZOS 152 triplet?


Actually it isnt APM branded, it is the TS that is sold by APM. It's the same as the Astronomics AT152ED.

http://apm-telescope...em/333633383531


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