40 replies to this topic

[jacobch]

I found this review to be quite accurate and fits my experience with the same refractor.  I have the Lunt version of this with a great focuser.  there is very little if any color when in complete focus.  I have been completely happy with this instrument.  It is not really very heavy and is quite portable.  I have never tried astrophotography with this.  I am sure it would work well for mono work and maybe with a lrgb  filter setup. 

Great scope especially for the money!.

cjacobson

[jacobch]

I have this scope except  its the Lunt version.  It is an excellent performer as the reviewer has suggested.  there is essentially no lateral color.  It snaps into focus.  Its a great buy for the price.  the color correction is much better than my old AP 178 f8 blue tube.  

this review was one of several very positive reviews on this very scope.  If you are in the market for a 6in APO or near APO this is it.  You probably will not see anything more with a  6 in triplet.  

My focuser is excellent.

CJacobson

[Mabalis]

Great article!  Now I'm thinking that I ought to go see what it will cost me to get refractorized . .  I'm running a 152 F8 dob, it would be great to compare them.  I'm nothing if not frugal and value oriented.  Thanks!

[RichA]

Just a side issue; describing the star images in a C9.25" schmidt as "bloated" is misleading and likely was the view at lower power in bad seeing .  A properly collimated SCT in (key) excellent seeing produces star images that are 1/2 the size of an apo of 1/2 the aperture, that's optical law.  If at high power the SCT produces star images bloated to twice normal size, and a completely unrecognizable diffraction pattern (which would be the result) then the optics would be many waves out of spec.  So before condemning any large aperture scope, consider adequate cool-down and seeing.

[hfjacinto]

Just a side issue; describing the star images in a C9.25" schmidt as "bloated" is misleading and likely was the view at lower power in bad seeing .  A properly collimated SCT in (key) excellent seeing produces star images that are 1/2 the size of an apo of 1/2 the aperture, that's optical law.  If at high power the SCT produces star images bloated to twice normal size, and a completely unrecognizable diffraction pattern (which would be the result) then the optics would be many waves out of spec.  So before condemning any large aperture scope, consider adequate cool-down and seeing.

The SCT in great seeing was an excellent scope, but the stars were larger than 6" APO.  So they were "bloated". I can see the difference is star size even with imaging. The SCT while a light bucket and letting go fainter also has some issue, for example it has large mirror shift and finding perfect focus was hard due the way the scope focuses (by moving the rear mirror). For the price an SCT is a great scope that is compact and is an excellent planetary imaging scope (see below)

 

 

But for star clusters the stars are bloated compared to my APO's, something about an APO and tiny stars.

[drd715]

My APM 152 is number 235. The 3.7 inch focuser is great  i enjoy the scope, it is a good value for the money.  The 152 is a long scope and does become less than perfectly stable in windy conditions.  When wi ds are calm and the sky is stable it produces a vreat view.  

 

For those persons put off by the size, APM has a 140 mm a bit shorter and even better spectrum in focus color crossings for astrophotography 

[tchandler]

Thank you for sharing your thoughts and impressions. I don't know the number of my APM 152; but it knows my number.

 

In February 2018 I transported the 152 to my sister's house in central Florida and had a great night of spitting doubles. Rigel was a snap; Messia and Theta Aur ditto. Had to wait for Sirius to clear a grapefruit tree but when it did - there was the Pup, sitting obediently. Funny, it would materialize during periods of calm air but only with the 13 mm and 5 mm EPs. It wouldn't show up in an 8 mm no matter what. The excitement at glimpsing the Pup for the first time was up there with seeing Saturn for the first time with my very first telescope, a 60 mm Tasco. 

 

The 152 is paired with an AYOII Digi Altaz mount, all on top of a Berlebach Uni24 tripod, making it a surprisingly portable system that gets outdoors and carted across North America on occasion. I opted for the smallest 2.5" focuser to help keep the weight down for this strictly visual set up.

[Jon_Doh]

The SCT in great seeing was an excellent scope, but the stars were larger than 6" APO.  So they were "bloated". I can see the difference is star size even with imaging. The SCT while a light bucket and letting go fainter also has some issue, for example it has large mirror shift and finding perfect focus was hard due the way the scope focuses (by moving the rear mirror). For the price an SCT is a great scope that is compact and is an excellent planetary imaging scope (see below)

 

 

But for star clusters the stars are bloated compared to my APO's, something about an APO and tiny stars.

This has been my experience with SCT's compared to the refractors I've owned.

[aa6ww]

My Friends standard C8 has produces noticeably brighter deep space objects then my 6" APM 152 refractor in side by sides. Its obvious as the deep space objects get dimmer. Optics don't mater its the aperture when your trying to pull in galaxies and nebula's

 

...Ralph

 

I have an 8” Schmidt cassegrain currently and looking for my next scop. Given the unobstructed view I’m speculating that I won’t lose any brightness on object vs my 8” SCT’s and it might be slightly better? Thoughts?

I’ve had friends suggest that I get a 16” dobsonian for more reach but I’m hung up on looking at refractors. I have access to a 12” dob from the club as well as a C14.

Jon

[lwbehney]

Hello Jon,
I have owned both the Lunt version of the APM 152 and a C8 and took them both out to compare them one night.  I thought the brightness of objects and stars was equivalent and the stars in the refractor are indeed smaller.
One person commented on this thread that the stars should be smaller in a larger aperture telescope, such as a C 9.25. This is not correct if you are speaking of the actual size of the Airy disk on the focal plane. According to "The Deep-Sky Imaging Primer" by Charles Bracken, the formula for the width of the central Airy Disk in microns is: W= 2.440(lambda)f/a, where lambda is the wavelength of the light being viewed, W is the width of the Airy Disk and f is the focal length of the telescope and a is the aperture. Well, f/a is also the focal ratio. So the f/8 refractor will always have a smaller Airy Disk than the f/10 SCT and furthermore, due to its unobstructed aperture, a greater amount of the light will be in the central Airy Disk than in the case of the SCT, which will dump more of the light energy into the outer rings of the Airy disk, which if there is any glare in your eyepiece, will also tend to bloat your star size. I also felt that the sky background was darker in my Lunt 152 than in my C8 and the edge of field was certainly better. 
I really liked that refractor, but I sold it when an Tak FS 128 became available. I had this decade's old desire to own a true fluorite refractor so I sold the Lunt to buy the Tak. I regret this sometimes. The images are brighter in the Lunt and just as well contrasted.  I have seen beautiful astro-images from the Lunt also and would have to admit, that although I like the FS 128 I own, the Lunt is a better scope (except for its focuser) when actually looking at a faint objects  particularly.
I had the bright idea that I could turn my C8 into a better scope by purchasing and using the Celestron f/6.3  reducer/corrector, but that failed, because if you use a low power eyepiece (long focal length eyepiece) with the C8  to expand your field of view, you will see the big fat secondary in the middle of whatever you are viewing. This field flattener is only useful in AP.
So in my mind, the Lunt provides the ability to see both wide and narrow field objects, pulls in almost as much light as the C8, has better contrast, tighter and more beautiful stars with a blacker background and has a faster native focal ratio if you wish to do AP and it is not heavy at all, considering it is a 6 inch refractor. I am 66 y.o. and did not find it difficult to heft it onto my CGEM II. 
By the way, I want to put in a plug for DSP and their mount hyper-tuning. Do yourself a favor, buy a used CGEM II and have it hyper-tuned; you will end up with a mount as smooth as glass worth twice as much as you paid for it. The whine I heard when I slewed my CGEM II turned into the soft buzz of a bee and it is just simply wonderful now as it floats my Tak FS 128 from one cluster or double star to another.

I also want to say an attaboy to Celestron for their Skyportal idea. The hand controller is nice, but using the Sky-portal and your iPad is better. This is why: occasionally you want to find a double star in a particular constellation. It is just a whole lot easier to use the search function in the Sky Safari Celestron program than it is to try to find it on the HC. Also, the Sky Portal already knows where you are and what time it is from the fact it is using your iPad, which is giving it all sorts of data.  It is nice to have a large tablet so that you have plenty of space for button pushing to slew your mount using your iPad or tablet. Sky Safari will also have a whole lot more information about what you are looking at than the HC has. 

I like having a second tablet available and use Sky Guide to help find objects to view and I like the fact it has nice space music to listen to while you use it. "Turn Left At Orion" and Sue French's book "Celestial Sampler" will provide you with a list of every great object you might want to see or image or both with a small telescope. 

One more item that I find useful that I want to share is: PS Align Pro an inexpensive app,  which displays among other useful things, the location of the Polaris in relation to the Celestial Pole. So for example, if you are using a CGEM II and are not sure about how well you have lined up the big dipper in the polar scope, just put Polaris at proper location of the clock face on the polar scope, based upon the location of Polaris, which the app is telling you it is located. On this day at this time of night, Polaris is at precisely the 10:00 position on the Celestron polar scope ring. My iPhone automatically tells the app what time it is and where it is. Really simple and pretty accurate. 

I think there is one thing the Celestron HC can do, which Sky Safari does not do, and this is help refine your polar alignment. However, I think that if you are close on the polar alignment, and are taking 3 minute subs or less with an auto-guider, you should be OK.  

Feel free to correct me about any of this if you disagree.

 

Larry

[aa6ww]

I also have a 8" SCT and by no means are my stars bloated in any way. They are beauifully crisp as all telescopes should be with proper alignment. My APM 152ED will split the tighter stars better especially as magnifications increase and overall, my APM will do everything better unless we are talking about light gathering. Id imagine in the worse seeing conditions, any scope is going to have bloated stars but id either realign my optics if I had any scope that produced bloated stars or just drop the entire scope in the garbage. 

As objects become dimmer, for example Mag 9 galaxies and dimmer deep space objects, its not even close that my C8 is the superior scope for pulling in these objects with more light.

My C8 was even better at pulling in deep space objects then my APM 180 refractor. 

In regular back yard observable deep space objects that are observable with small telescopes, on open clusters, globulars etc, you wont see any thing earth shattering one way or the other. Both scopes should produce excellent results because you are basically looking at the brighter stars in these clusters.  

I don't own SCT's that aren't collimated and I know how to make sure my SCT's are acclimated before I start judging their optics. On nights where there aren't side by side comparisons, you cant realistically make true comparisons since different nights produce different seeing and transparency results.

There is nothing special about my APM 152's ability to pull in deep space objects any better then any other 6" telescope, any way you slice it, 6" of aperture is still 6" of aperture and 8" wins every time when you need to pull in light to see dim objects.

I don't notice any back ground skies being darker in my APM vs my C8. The APM may give the illusion of it having darker back ground skies because it less aperture but then again, everything will be dimmer. There is still nothing special about its ability to pull in deep space objects better or worse then any other 6" telescope, reflector or achromat. 

 

...Ralph

[peraspera]

Hi,

This telescope looks very nice. Does the manufacturer provided interferogram when buying it ?

 

J.

[nato]

     If I didn't already own a 4" Refractor from the 1970's (Edmund scientific) with over the top images and a fair mount I would buy this scope based on your excellent review. I have looked through a s-pot of contemporary refractors and this one sounds /looks like it would be the one to recommend for a number of users. Some of the recent large refractors are very heavy and not easy to set up. I know I have helped several people with theirs. Nate Goodman (Nato). Salt Lake, Utah.

[MikiSJ]

I am only recently coming back to Cloudy Nights as I left the sport nearly a decade ago.

 

I imaged with an APM-TMB 152/1200 TRIPLET I bought in 2008 (serial number 224). It was every bit the scope the OP reviewed and more. The only complaint I had with the scope was the FT focuser. It would not hold a QSI camera and ST-4 autoguider so I mounted a Robofocuser and no further problems.

 

With the exception of the FT focuser I would rate this scope A-(mechanics)/A++(optics). I had to store the scope as I had sold the Paramount ME that moved this fine piece of astronomy equipment around the skies from my San Jose, CA backyard.

 

This scope is currently listed new at $13,000 and is sold out. Such is the value of this scope. I recently traded mine to a SoCal retailer and bought a C11 on a CGX.

[hfjacinto]

My latest image with the APM 152

 

[DENISANNA]

Hi, compelled to add my two cents worth !! Just purchased my APM 152 and am stuck with the new telescope curse !! All I can do is read reviews about it, set it up on my EQ6-R-Pro, add all the accessories and play pretend with it !!! The Chilean dessert is looking good right now !!! Is there anything I can sacrifice, pray or wish upon to alleviate this curse ??? Chopping heads on top of a pyramid is out of the question, messy and unproductive. I'd swear to give my left testicle for science purposes if I could get a sky break here !!!