108 replies to this topic

[starman876]

I figured while I have both these scopes it would be a good time to compare the two.  Old versus the new.

 

They are both F8 scopes which puzzles me when I look at the two OTA's.

 

The 1986 6" AP does not have a sliding dewshield which means it takes a longer case to store it.

 

However, the older AP is very nicely balanced while the APM scope is very heavy in the front.  

 

The AP is a 6" triplet with no exotic glass while the APM is an ED  doublet with one lens made with FPL-51.

 

The AP has a plain rack and pinion 2.7" focuser.   I put a JMI electric focuser on it.

 

The APM has a really nice two speed focuser.  

 

They both weigh in at around 24 lbs.

 

The paint on the old AP is still in fantastic codintion

 

The paint on the APM is like white metal flake. Looks very nice.  

 

The OTA on the older AP is larger in diameter.  Will take measurements later.

 

DPAC results will follow shortly.

 

The AP is the scope on the right.

 

Edited by starman876, 19 August 2018 - 07:30 AM.

[Richard O'Neill]

Will you followup with a comparison of the optics and images they produce?

[starman876]

i will do my best to provide all the information i can

[starman876]

Here is the DPAC of the AP 

 

 

 

 

[starman876]

Here is the DPAC of the APM

 

 

[starman876]

Like I stated in other posts, Roland certainly made some fine optics in 1986. Here we have a relatively fast refractor for the time at F8 and it is a lens that performs very well at this speed.

[Jimmy462]

Hi starman876,

 

Could you denote for each pair of images which were inside focus and which were outside focus? It's clear that both objectives have edge issues and that the APM is, um, slope-ier across the surface than the AP...well, to these eyes.

 

Thanks,

Jimmy G

[Element79]

Roland certainly did make some fine optics in the 1980's (and ever since!).  Too bad that the glasses weren't available then to make a truly outstanding telescope. Between the two, I'll take the APM...

[John Turley]

Roland certainly did make some fine optics in the 1980's (and ever since!).  Too bad that the glasses weren't available then to make a truly outstanding telescope. Between the two, I'll take the APM...

The APM will almost certainly be better colour corrected, it also has a much better focusing mount than the original one fitted to the the AP Refractor.

 

John

Edited by John Turley, 20 August 2018 - 04:33 AM.

[roadi]

The APM will almost certainly be better colour corrected

 

John

  

[Don W]

I had one of those 6" APs back in the early 90s. Performed nicely.

[Bomber Bob]

Thanks for the DPAC results, Johann.

 

I've run almost all my refractors through my DPAC rig.  In general, patterns with thin, jet black, sharp-edged, straight bars outperform those with messier patterns.  APM is obviously lower quality than the AP.  But it's tough to predict where you'll see the differences -- too many other factors.  I will run my APM152 through the rig.  If the photos are decent, I'll post them, though my camera distorts patterns to make sharing them useless.

 

Based on the DPACs, I'd say the AP will win on fine detail at equivalent magnifications.  The APM may win on particular objects, like star clusters, fainter nebulae -- but again, tough to predict.

[Bonco2]

Oh how I miss my 6 inch f/8 AP. Perhaps the best optics I've ever owned.

Bill

[Richard Whalen]

I would take the AP over the APM in a heartbeat.

[Element79]

I would take the AP over the APM in a heartbeat.

If it were a modern AP then I would most certainly agree, but CA really bothers me, even just a little bit of it!  And although the 6" f/8 was a marvel back in the 1980's when it was introduced, it did have easily detectable CA...

[Wildetelescope]

If it were a modern AP then I would most certainly agree, but CA really bothers me, even just a little bit of it!  And although the 6" f/8 was a marvel back in the 1980's when it was introduced, it did have easily detectable CA...

Both scopes are beautiful.  I can't speak for the 6 inch AP, but the ONLY ca I have ever seen in my 5 inch AP f8 (visually) is a very faint indigo halo around bright stars.  NEVER on the moon and planets other than Venus.  On good nights, the visual detail is breathtaking. Even for imaging, the scopes capability greatly exceeds my skills, for the moment;-).  If your focus is imaging, then a more modern triplet surely makes sense, but in my opinion these older AP non-ED triplets are wonderful scopes for visual observation and casual imaging efforts. It would not surprise me in the least If that AP gives the ED doublet a good  run for its money in all departments including color correction.    I am very jealous of Starman 876 and can't wait to hear his assessment of the two scopes under the stars:-).   

 

Cheers!

 

JMD

[Zubenelgenubi2]

There is something cool about a vintage AP.

I have an APM 152ED and realize it would optically beat the 1980's AP but still only worth a tenth the value. Kind of like a Timex watch and a Rolex; and I would pay for the Rolex, (if I could afford it).

Clear skies,
Peter

[Jeff B]

Based upon the DPAC results alone, I'd take the old AP without hesitation.

 

I would much rather have an objective that misses a little at the extremes of the deep red and blue but has an excellent figure in between, over one with better color correction but also a turned edged, SA in the heart of the visual range and a rather strong zone in the middle (though that's where a zone does the least damage).   

 

I have a feeling high power images of say Jupiter would be very sharp via the AP but the planet would have a mild purple boarder and maybe a slight yellow tint.  This particular APM might have less to no visible CA, a slightly whiter tint, but also a noticeably softer image at high power.

 

At lower powers, like looking at open clusters and star fields, I image there would be little to choose between them.

 

As I've commented before, those who think these older AP's are "old school" and not capable of fine views, need to go back to school.

 

But I'm guessing based upon my own experiences comparing vintage AP objectives with more modern ones and, of course, I'm dying to hear Starman's comparisons.  

 

Jeff 

[starman876]

some great comments from all of you. thanks. have not posted much after 10 yesterday morning
seems my brain took a vacation about that time. everything seems to be ok now. docs will let me know sometime day if they find anything after all the tests they ran.

[dpastern]

some great comments from all of you. thanks. have not posted much after 10 yesterday morning
seems my brain took a vacation about that time. everything seems to be ok now. docs will let me know sometime day if they find anything after all the tests they ran.

well that doesn't sound good.  Best wishes that everything is AOK.

 

On topic, I look forward to more on the comparison when you are feeling up to it.

[Steve Allison]

Optical figure is most important to me. Who cares if there is a tiny bit of color in certain objects at high power if the image is critically sharp? My 90mm F15 achromat is razor sharp at the powers permitted by my local seeing conditions with little or no color on the objects I like to observe. Some of the less expensive apos I have looked through were not as sharp, even though they had excellent color correction. An inferior optical figure was likely the culprit. 

 

If my desire was to stare at Sirius or Vega all night long at high power, I would take the less well-figured APM, assuming it has the superior color correction. For the type of observing I and most other visual observers do, the AP, with its more highly corrected object glass, would be a better choice.

 

Regards

 

Steve

[MooEy]

Isn’t the AP suppose to use some kind of short flint? Don’t think it will be that good at F/8, but still pretty good.

[starman876]

the AP has always provided wonderfull views.  to be honest i never noticed any color on Jupiter. have used it at powers of up to 472x.  there have been other reviews of similar AP'S in where people loved the views through the scope.  when i get a chance i will compare the APM and see which scope provides the better views.  j

[roadi]

Be careful! Even though the AP has the better figure, your Apm still has respectfully 0.95 strehl. You might be in for a surprice! 

[BarrySimon615]

Adding another telescope to the mix...….assuming good/great collimation how would one of the Meade doublets from the early to mid 90's compare?  I know these scopes all f/9 in 4", 5", 6" and 7" apertures were plagued with poor objective cell design and a very strong tendency to de-collimate.  However can anyone, particularly one who owns/owned a decently performing 6" f/9 care to comment?  Particularly if he or she has compared the old Meade to the APM 152 ED, or the AP 6" doublet from the late 80's or even to the new SkyWatcher 150 mm ED doublet.  Inquiring minds want to know.

 

Barry Simon