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APM 152 ED APO club

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#601 ASTERON

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Posted 30 August 2020 - 04:07 PM

I could imagine yours has a good .97 strehl. At least one instrument with this measurement was sold a few days ago.

 

With some luck my refractor with 3.7" focuser will arrive tomorrow. I am already very curious. However, I had to buy a decent clamp for losmandy level especially for this refractor.

 

Currently I own a 152/900 achromat, which is nice. But an ED is even better. I am very interested in first comparison observations.

 Hi Robert,

Forgive my curiosity, but how do you know that a scope with such specs was sold ?belushi.gif  do you work at APM ?


Edited by ASTERON, 30 August 2020 - 04:09 PM.


#602 Robert Zebahl

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Posted 30 August 2020 - 04:41 PM

 Hi Robert,

Forgive my curiosity, but how do you know that a scope with such specs was sold ?belushi.gif  do you work at APM ?

I called APM and asked for available refractors including the test reports. One with strehl 0.97 was already reserved. So nothing special smirk.gif


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#603 HCR32

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Posted 31 August 2020 - 02:04 AM

Has anyone compared their APM 152 to any other 152-160mm refractors. How did it fair?

#604 CHASLX200

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Posted 31 August 2020 - 05:54 AM

Has anyone compared their APM 152 to any other 152-160mm refractors. How did it fair?

My APM 152 ED and Skywatcher 150ED ran neck and neck by heck.


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#605 ASTERON

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Posted 31 August 2020 - 06:35 AM

I called APM and asked for available refractors including the test reports. One with strehl 0.97 was already reserved. So nothing special smirk.gif

Oh,  than it may be the scope I got but the report on mine says Strehl = 0.977  PV 0.21 Lambda.  It looks like I got a good optic after all.tongue2.gif lol.gif waytogo.gif


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#606 Robert Zebahl

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Posted 31 August 2020 - 06:39 AM

Oh,  than it may be the scope I got but the report on mine says Strehl = 0.977  PV 0.21 Lambda.  It looks like I got a good optic after all.tongue2.gif lol.gif waytogo.gif

For sure waytogo.gif  I also received mine last week with a stated strehl of 0.962 (PV 0.139 lambda, RMS 0.027 lambda), which is also pretty good for that price. Not perfect, but overall a good correction. I just had one chance to test it under the stars and I was very impressed by the views of DSOs and double stars. No comparison to my 152/900mm achromat.


Edited by Robert Zebahl, 31 August 2020 - 06:50 AM.

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#607 ASTERON

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Posted 31 August 2020 - 06:41 AM

Has anyone compared their APM 152 to any other 152-160mm refractors. How did it fair?

I don't have another 152-160 scope to compare it with.  However for what its worth, I can compare it with my APM/LZOS 130mm F/6 triplet ( kinda comparing apples with oranges, but what the heck)bounce.gif

whether has nor exactly been cooperating lately though....bangbang.gif


Edited by ASTERON, 31 August 2020 - 06:50 AM.


#608 ASTERON

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Posted 31 August 2020 - 06:49 AM

For sure waytogo.gif  I also received mine last week with a stated strehl of 0.962, which is also pretty good for that price. Not perfect, but overall a good correction. I just had one chance to test it under the stars and I was very impressed by the views of DSOs and double stars. No comparison to an achromat.

Robert,

That's great to hear !  Did you try it on the planets and moon ?  Did you see any Ca on bright objects ? How was the contrast ?

P.S. - What do you mean "not perfect"?  Did you expect strehl 1.0 ?  lol.gif

Thanks

Lihu


Edited by ASTERON, 31 August 2020 - 06:53 AM.


#609 Robert Zebahl

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Posted 31 August 2020 - 07:03 AM

Robert,

That's great to hear !  Did you try it on the planets and moon ?  Did you see any Ca on bright objects ? How was the contrast ?

Thanks

Lihu

No moon, no planets yet. I have to walk almost 200 meters for them. But I observed some double stars like lambda Cygni (4m8 / 6m3, 0.9"): At 300x two clear airy disks slightly overlapping. No color was seen. Even on Vega there was no color at first glance. On closer look the diffraction rings appeared in slight red. Overall the color correction seems to be very good. This scope is probably comparable to my 102/1122mm ED refractor. The contrast was also very good, but I have no comparisons yet. Objects like Messier 57 or Messier 27 were extremely nice at 133x and 171x. Evenly black background with pinpoint stars.


Edited by Robert Zebahl, 31 August 2020 - 07:03 AM.


#610 ASTERON

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Posted 31 August 2020 - 07:08 AM

No moon, no planets yet. I have to walk almost 200 meters for them. But I observed some double stars like lambda Cygni (4m8 / 6m3, 0.9"): At 300x two clear airy disks slightly overlapping. No color was seen. Even on Vega there was no color at first glance. On closer look the diffraction rings appeared in slight red. Overall the color correction seems to be very good. This scope is probably comparable to my 102/1122mm ED refractor. The contrast was also very good, but I have no comparisons yet. Objects like Messier 57 or Messier 27 were extremely nice at 133x and 171x. Evenly black background with pinpoint stars.

Fantastic !  Hope mine proves to be as good as yours bow.gif



#611 Robert Zebahl

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Posted 31 August 2020 - 07:19 AM

Fantastic !  Hope mine proves to be as good as yours bow.gif

Well, I asked APM to send me the test protocols of the available refractors to have a choice. So for me no big surprise regarding quality.



#612 Robert Zebahl

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Posted 31 August 2020 - 08:16 AM

Robert,

That's great to hear !  Did you try it on the planets and moon ?  Did you see any Ca on bright objects ? How was the contrast ?

P.S. - What do you mean "not perfect"?  Did you expect strehl 1.0 ?  lol.gif

Thanks

Lihu

Strehl 1.0? Of course grin.gif

 

Having a scope with a certain Strehl value can have different combinations of aberrations. Some are more apparent in focus (like coma) to my eyes, others not so. Mine has for instance little coma, but it is still good. I haven't noticed this during my first observation, but could be due to not so good conditions. For me it seems to be a huge improvement over my achromat, even on deepsky objects.


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#613 Bomber Bob

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Posted 31 August 2020 - 11:42 AM

My 2017 model has a Strehl of .926...  At that time, Markus posted that APM tested 100% of the aperture, while those vendors who did share / post lab results tested only the central 95% - 90% -- didn't include any edge errors in the their results...

 

Is APM still testing 100% of aperture?

 

If mine had a .962 Strehl, would I see 4 albedo features on Ganymede at 400x versus the 3 that I've seen?  


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#614 ASTERON

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Posted 02 September 2020 - 07:39 AM

First light report - Last night I  schlept the new APM152 on a DM6 mount and Berlebach planet to my back yard for first light.

Conditions were mediocre ( Full moon, seeing was Meh...).  Around 9:30 PM, I went for Saturn and Jupiter. I was using Mono viewing with a 5mm Pentax XW and a Baader 2" prism diagonal. Pushed to x240 Jupiter was magnificent with clearly distinct brownish main atmospheric bands and swirls within them (red spot was not visible).  I detected very slight CA on Jupiter which may have been the result of its relatively low altitude and atmospheric refraction. ( however, no CA was observed on stars when the stars were in focus)

I switched to using my Denkmeier Bino with OCS and 12mm Paradigm eyepieces. binocular vision gave a distinct increase in contrast and detail I was able to push magnification to >X350  and still see plenty of details in the bands.

Switched to Saturn (with Bino) which was magnificently creamy yellow at high magnifications, the Cassini division was very nicely observed as were some subtle color variations on the planet.

I then turned to the full moon, too bright to test contrast (no terminator), but I liked what I saw despite my preference for quarter moon I could identify many large and small craters. I will test again at quarter moon which would be better for observing tiny details.

I did not attempt any star test or double star resolving  because of the full moon - so will have to do so in a couple of weeks at our dark site.

I knew Mars is gonna be high in the sky later at night, so I left the scope to fully acclimate and went inside the house and watched TV until about 2AM, went out and stared to observe Mars for about an hour. To my utter delight, the atmosphere stabilized and seeing improved significantly, I was mesmerized by the amount of details visible on mars at X300 (with Bino), it was an orange-reddish color with clearly defined dark features and a nice whitish cap. I've never seen so much detail on Mars, even with SCTs of up to 10". 

I finished the session at 3AM, bleary eyed from oogling Mars for an hour but very very happy at the scope's performancebigshock.gif

I am very happy with this scope and I can hardly wait to use it under really dark skies.banjodance.gif


Edited by ASTERON, 02 September 2020 - 07:47 AM.

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#615 Deadlake

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Posted 07 September 2020 - 05:12 AM

First light report - Last night I  schlept the new APM152 on a DM6 mount and Berlebach planet to my back yard for first light.

Conditions were mediocre ( Full moon, seeing was Meh...).  Around 9:30 PM, I went for Saturn and Jupiter. I was using Mono viewing with a 5mm Pentax XW and a Baader 2" prism diagonal. Pushed to x240 Jupiter was magnificent with clearly distinct brownish main atmospheric bands and swirls within them (red spot was not visible).  I detected very slight CA on Jupiter which may have been the result of its relatively low altitude and atmospheric refraction. ( however, no CA was observed on stars when the stars were in focus)

I switched to using my Denkmeier Bino with OCS and 12mm Paradigm eyepieces. binocular vision gave a distinct increase in contrast and detail I was able to push magnification to >X350  and still see plenty of details in the bands.

Switched to Saturn (with Bino) which was magnificently creamy yellow at high magnifications, the Cassini division was very nicely observed as were some subtle color variations on the planet.

I then turned to the full moon, too bright to test contrast (no terminator), but I liked what I saw despite my preference for quarter moon I could identify many large and small craters. I will test again at quarter moon which would be better for observing tiny details.

I did not attempt any star test or double star resolving  because of the full moon - so will have to do so in a couple of weeks at our dark site.

I knew Mars is gonna be high in the sky later at night, so I left the scope to fully acclimate and went inside the house and watched TV until about 2AM, went out and stared to observe Mars for about an hour. To my utter delight, the atmosphere stabilized and seeing improved significantly, I was mesmerized by the amount of details visible on mars at X300 (with Bino), it was an orange-reddish color with clearly defined dark features and a nice whitish cap. I've never seen so much detail on Mars, even with SCTs of up to 10". 

I finished the session at 3AM, bleary eyed from oogling Mars for an hour but very very happy at the scope's performancebigshock.gif

I am very happy with this scope and I can hardly wait to use it under really dark skies.banjodance.gif

 

How does this compare with your APM 130mm (in your equipment list), particularly on planets. Looking for a step up from SD103S, in the frame are 130 mm LZOS or APM152. Thanks 



#616 Bomber Bob

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Posted 07 September 2020 - 08:36 AM

Finally!  Last night I got to test my 152 on this platform:

 

APM ED 152 S041 - Meade SF & Losmandy CP-100.jpg

 

For the 1st Time Ever, I was able to move my 152 during a session.  Initial set up was at the north end of the back yard for Jupiter & Saturn.  Took just a few minutes to relocate to the center of the yard:  Take the scope from the rings & lay it on a foam pad, remove counterweights, tote mount, and set up as normal.  No damage to the gear or myself.

 

It was a deep-sky night (clear skies but turbulent air), but I got highly detailed & colorful views of both gas giants.  Seeing limited the magnification to 300x (only usable in the calmest minutes), with most of the time at 240x (Nagler 5).  As usual, more detail on Jupiter than I can sketch.  I saw Titan + 4 small moons at Saturn, and very subtle belt colors.  Given the seeing, quite remarkable.

 

For deep sky, I switched to 2" accessories.  Just for fun, I popped in a vintage UO 50mm Plossl for 24x, and challenged myself to discern DSOs at that low power.  And, I did -- dozens of clusters & nebulae while sweeping the Milky Way.

 

Sessions like last night remind me why I bought this Big ED.


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#617 ASTERON

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Posted 07 September 2020 - 09:43 AM

How does this compare with your APM 130mm (in your equipment list), particularly on planets. Looking for a step up from SD103S, in the frame are 130 mm LZOS or APM152. Thanks 

Hi Deadlake,

 

I have not yet made a side by side comparison.  In the next new moon I am going to our dark skies site, where I will be doing a side by side comparison.  I'll update here when this happens.

FWIW - Just from memory, the 130 is completely color free (at least I cannot detect any CA), while the 152 has some tiny hint of color on the full moon.  on the planets both are wonderful but I need a more thorough comparison under the same skies to confidently say anything. 

I also need to test different diagonals and eyepieces on both scopes to make sure of what I am seeing.

I Hope  the whether cooperates this time


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#618 Deadlake

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Posted 07 September 2020 - 10:57 AM

Hi Deadlake,

 

I have not yet made a side by side comparison.  In the next new moon I am going to our dark skies site, where I will be doing a side by side comparison.  I'll update here when this happens.

FWIW - Just from memory, the 130 is completely color free (at least I cannot detect any CA), while the 152 has some tiny hint of color on the full moon.  on the planets both are wonderful but I need a more thorough comparison under the same skies to confidently say anything. 

I also need to test different diagonals and eyepieces on both scopes to make sure of what I am seeing.

I Hope  the whether cooperates this time

Thanks, looking forward to the comparison. Also would be interested to know difference in acclamation time, I'd imagine both scopes would be pretty close.



#619 Astrojensen

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Posted 07 September 2020 - 12:47 PM

Finally!  Last night I got to test my 152 on this platform:

 

attachicon.gifAPM ED 152 S041 - Meade SF & Losmandy CP-100.jpg

 

For the 1st Time Ever, I was able to move my 152 during a session.  Initial set up was at the north end of the back yard for Jupiter & Saturn.  Took just a few minutes to relocate to the center of the yard:  Take the scope from the rings & lay it on a foam pad, remove counterweights, tote mount, and set up as normal.  No damage to the gear or myself.

 

It was a deep-sky night (clear skies but turbulent air), but I got highly detailed & colorful views of both gas giants.  Seeing limited the magnification to 300x (only usable in the calmest minutes), with most of the time at 240x (Nagler 5).  As usual, more detail on Jupiter than I can sketch.  I saw Titan + 4 small moons at Saturn, and very subtle belt colors.  Given the seeing, quite remarkable.

 

For deep sky, I switched to 2" accessories.  Just for fun, I popped in a vintage UO 50mm Plossl for 24x, and challenged myself to discern DSOs at that low power.  And, I did -- dozens of clusters & nebulae while sweeping the Milky Way.

 

Sessions like last night remind me why I bought this Big ED.

And here, it's been a month or so, since I was out last time with my APM 152. The weather hasn't been cooperating since and doesn't look like it will for the foreseeable future. fingertap.gif gaah.gif

 

Clear skies!
Thomas, Denmark



#620 Robert Zebahl

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Posted 08 September 2020 - 02:59 AM

Hi,

 

yesterday evening I could finally observe and compare my 152/900mm achromat (slightly undercorrected) and the new 152/1200 ED (Strehl 96.2%). On the planet there is no need for comparison. The difference would be obvious. For us the question remained whether differences can be seen on deepsky objects as well.

 

In general it can be said that the ED shows natural, more intense star colors and the contrast is noticeably higher. But does it also show more details?

 

Before I get into details, one important note: I am comparing two concrete instruments here, whose optical quality alone is quite different. So one should not consider this in a generalized way. But for me personally, this is enough, because I only have these instruments. However, today it might be easier to get an optically & mechanically decent ED than an achromat.

 

The achromat is equipped with a Baader Maxbright T2 mirror, the ED with a William Optics Zenit mirror. The conditions were pretty good in Leipzig (Bortle 6, SQM-L 19.2, NELM 5m2+). Both mirrors are of comparable quality.

 

First I used the well-known Egg Nebula (PK80-6.1) in Cygnus. In the ED at 171x (7mm DeLite) the nebula was clearly elongated, the northern "knot" appeared much brighter & rather round. The southern extension was slightly separated and slightly elongated. The image was very contrasty and the stars appeared pinpoint. Even at 300x the image was really nice and the structure was even more clearly visible. The achromat at about 165x (Nagler zoom ~5.5mm) showed the nebula also elongated, but the whole image looked more blurred and less contrasty. Fainter stars were less obvious. The separation of the two "knots" was hardly visible. At 300x this impression became stronger. But the stars themselves were also sharp in the achromat with defined focus. The nebula seemed to be a bit larger and more diffuse.

 

Next I observed the Cheeseburger Nebula (NGC 7026). At about 171x the ED showed clearly the more beautiful image. The nebula could also be magnified very well. At 300x the achromat showed a nearly round nebula with a very diffuse edge, getting little bit brighter towards the middle. It was and remained a diffuse nebula. Later I added the Baader long pass filter (light yellow), which increased the contrast. The nebula appeared a bit smaller and fainter. The dark band was not visible. When I first set the nebula in the ED at 300x, I was overwhelmed by how defined and clear the nebula appeared. The dark band was immediately visible! Regardless of this comparison I would not have expected it under these conditions. I tried to see the dark band in the achromat, but without success.

 

In between I observed the small Dumbbell Nebula, where the ED also revealed internal structures more easily. But I only left it at a short observation.

 

Just the observation of NGC 7026 under urban conditions showed me that my ED is clearly superior to my achromat. Under dark skies the differences could be even greater.

 

BR,
Robert


Edited by Robert Zebahl, 08 September 2020 - 03:28 AM.

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#621 ASTERON

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Posted 13 September 2020 - 03:46 AM

Hi,

Just  a brief report of a short dark site first light.   Last Friday I went to our dark site with the APM 152.  The seeing was not very good ( we had a cloud cover until 9PM a couple of hours of mediocre seeing and then suddenly seeing deteriorated seriously ( some kind of haze or what not).  even under mediocre conditions the scope performed very well on planets and globular clusters.  Because of the atmospheric conditions I cannot report any serious star test or diagonal/eyepiece comparisons as I wanted.  Moon rose at 0130 ending the session.

What I can report is that comparing the Frac to a 20" Dobsonian F 3.3 and to another a 14" dob with a Zambuto mirror on planets  showed that the frac was definitly superior on the planets under these specific atmospheric conditions.

 

I really hope to get some decent seeing on our next session at new moon, so I can compare the 152 with my  130 APM/LZOS triplet under good conditions.

 

Regarding cool down time, I cant say anything because the scope was taken from 25 degrees centigrade room and the ambient temperatures during the session were in the 24-22 degrees centigrade range , so not much  of a temp. gradient.  For more serious cooldown estimates will have to wait for full winter ( Jan-Feb. 2021).  A couple of photos to show final setup in the field.

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#622 ASTERON

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Posted 13 September 2020 - 07:32 AM

Higher res. photo of setup.

Some improvement need to be done.

The Alt-Az mount is the DM6. However the 8" riser I used was for the DM4 because I  do not own the bigger riser for the DM6.  So stability was somewhat  compromized.  I will order the 8" riser for the DM6 soon (For my 12"Meade ACF).  There is also a 6"diameter custom made 12" height riser in the works for  the refractor so I can observe near Zenith without crawling on the floor lol.gif

 

Another improvement will be a Nexus Wifi Controller with an 8-10 inch tablet with Sky Safary.  I will also like to add a push handle on the Saddle plate of the DM6 for ease of manipulation.

 

I an using an Amici prism  2" Baader correct image diagonal with the scope - However, my finder is a straight-through 7X50 Meade finder.  The view in the finder is inverted from the view in the scope.  Can anybody recommend a high quality wide angle finder with an Amici prism ??

 

If Rowan Astronomy will ever implement the tracking motors on the Rowan Az100, I may be heading that way because it will allow me to put two scopes on the same mount.

 

 Does 12"ACF + 6"APM  on the same mount with tracking sound too much ?tongue2.gif

 

Anybody with an Az100 would like to comment/negate/critisize  this idea ?

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Edited by ASTERON, 13 September 2020 - 07:55 AM.

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#623 aa6ww

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Posted 15 September 2020 - 02:35 PM

When Im out with my 152ED or other scopes, I really dont like looking through other peoples scopes.

 

  ...Ralph

 

Has anyone compared their APM 152 to any other 152-160mm refractors. How did it fair?




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