Review – Explore Scientific AR152 Achromatic Refractor

I have wanted to own a large refractor for a long time, but I just never could justify purchasing one. I certainly can’t fit a large apo into my budget and reflectors seem to be an overall better value.  However, I eventually decided to do some research on 6″ achromats and took the plunge with an Explore Scientific AR152, a 6″ (152mm) f/6.5 achromatic refractor. The AR152 has received several good reviews since it came out, along with all of Explore Scientific’s products, and is offered at the unbelievable price of $750. I also considered purchasing the Celestron C6R or the Celestron Omni XLT 150R.  However, I was afraid the C6R, with its longer OTA at f/8,  would be too unwieldy for the CG-5 I planned to mount it on and the Omni XLT 150R was a little faster than I wanted at f/5. Also, the AR152 purportedly had a better build quality and better accessories than the Celestron offerings. I have now owned the Explore Scientific AR152 for 5 months, which is plenty of time to have experienced all of the good and bad things about this telescope. Let’s start from the beginning:

I ordered my AR152 from Astronomics, http://www.astronomics.com, in late September 2012 for $750. My order also included a Celestron CG-5 ASGT mount for the AR152 which was an additional $700. As usual, Astronomics was very quick in shipping my order.  I placed my order on Wednesday night and had the scope and mount by Saturday.

The telescope arrived in a single box which included the OTA, cradle with handle, dovetail mounting bar, 2″ dielectric diagonal, and an 8×50 straight through finder. There were no instructions of any kind included with the scope. All of the components have a solid high quality feel that exceeded my expectations given that this is a budget oriented achromat. I expected a few more cut corners for a large refractor at this price point.

Unboxed AR152

Instead of using the 8×50 straight through finder that came with the AR152 I decided to install a GSO 8×50 right angle correct image finder. I had to remove my GSO right angle finder from its stock bracket and install it in the finder rings that came with the AR152 since the GSO finder bracket has a Vixen style dovetail which isn’t compatible with the AR152. The AR152 finder rings have a spring loaded screw on the top of each ring and two nylon screws for adjusting the alignment of the finder. Once aligned, the finder holds alignment pretty well between observing sessions.

GSO 8×50 RACI in Stock AR152 Finder Rings

The AR152 is a large scope, but it wasn’t the beast I expected it to be.  I find the OTA to be quite easy to manage thanks to the included handle attached to the scope’s cradle — a very nice touch. The scope balances close to center on the CG-5 in declination, but one thing became clear very quickly — I should have ordered an extra 11lb. counterweight for the CG-5.  The CG-5 comes with one 11lb. counterweight, which isn’t near enough to balance the 23.5lb. AR152. Luckily, my CG-4 mount had a 7lb. counterweight that fit the CG-5 and was just enough to balance the AR152 in RA. I promptly ordered an extra 11lb. counterweight for the CG-5.  In practice the CG-5 has proven to easily handle the AR152 for visual use up to magnifications of about 250x with the tripod legs partially extended.

AR152 on CG-5 (left) – Celestron Omni XLT 102 on CG-4 (right)

 

AR152 (foreground) ES 127 ED Apo (background)

 

The front lens of the AR152 is gorgeous. The lens is a deep green color and has 3 sets of 2 push-pull type collimation screws for adjusting the collimation. The inside of the tube is nicely baffled and painted a very flat black and produces no reflection when shining a light down the tube.

AR152 Objective Lens (Black background is the inside of the dew shield.)

 

AR152 lens (left) – Omni XLT 102 lens (right)

 

The AR152 sports a large dew shield that is held on by friction provided by three strips of felt attached to the lens cell. To remove the dew shield you just simply pull it forward. The dew shield is also quite effective — I’ve never had the front lens dew up even in farily heavy dewing conditions.

The focuser on the AR152  is a 10:1 dual speed focuser with a  thumb screw for locking the focus and another thumb screw to adjust the tension. The focuser on the AR152 I received was pretty terrible. It would grab/jerk at certain points along the focuser’s travel.  After racking the focuser in and out a half dozen times hoping  it would smooth out, 2 lines/scratches began to appear on the focuser tube where the paint was being rubbed off. I called Explore Scientific and they promptly sent me a replacement focuser. The new focuser arrived about 3 days later with a prepaid shipping label for sending the original focuser back. The new focuser was very easy to install (there are only 2 set screws holding the focuser to the OTA) and was very smooth with no problems. The focuser holds the diagonal and all of my heavier 2″ eyepieces without any slippage near zenith.

Optical Performance

Collimation

My AR152 either arrived very slightly out of collimation or installing the new focuser caused a slight misalignment. I used a cheshire collimation eyepiece designed for collimating refractors to tweak the collimation which only took about 10 minutes. I just tweaked the push pull collimation screws one set at a time until I discovered the one that needed adjustment. The adjustment needed was very slight.

Chromatic Aberration

Chromatic Aberration (CA), the inability to bring all wavelengths of light to focus at the same point, is inherent in all achromatic refractors, especially ones with fast focal ratios like the f/6.5 AR152. This optical aberration manifests itself as a violet halo around the brightest objects and also causes a slight loss of contrast due to unfocused wavelengths of light. If you tend to be bothered by CA, or if you’ve never owned an achromat before, this is not the telescope for you. There is plenty of CA on objects of 2nd magnitude and brighter and it gets worse on nights with poor atmospheric conditions.  On nights of poor seeing, I’ve seen CA on objects as dim as 3.5 magnitude. On nights of good seeing, the CA is actually pretty well controlled and not all that distracting. The seeing conditions on my first night out with the AR152 were pretty bad. While trying to split E. Lyra (the double double)  I was able to get a dirty split; however, all 4 components exhibited a greenish color. A few nights later I tried E. Lyra again with better conditions and got a very clean split with all 4 components showing a normal white color. The only object that the CA has really bothered me on is the double star Alberio. At magnifications of less than 50x the blue and gold color of the stars is visible, but anything over that causes the striking colors to be lost to CA.

Chromatic Aberration on the Moon. (This is a low quality image taken by holding a cell phone camera to the eyepiece. Eyepiece is an 8.8mm Meade 5000 UWA giving 112x.)

 

I’ve tried using a 2″ Baader Semi-Apo filter to help reduce some of the chromatic aberration, but found that I actually preferred the unfiltered view. For me the filter dims the view too much and reduces contrast. Other reports have indicated that the Baader semi-apo increases contrast, but that was not my experience.

More recently I acquired  a 2″ Baader Fringe Killer filter which has a higher light throughput than the semi-apo filter. I’ve found the Fringe Killer to be a much better filter overall than the semi-apo. The Fringe Killer reduces some of the violet fringing around bright objects and increases contrast without dimming the view like the semi-apo filter.  The Fringe Killer does impart a slight yellowish tint to some objects, but I find this a lot less objectionable than the dimmer view provided by the semi-apo filter. I plan on leaving the Fringe Killer in the diagonal pretty much all the time.

Moon and Planets

To the apo only crowd, viewing the Moon and planets with a large fast achro is like committing an unpardonable sin. These folks will have you believing that an achromat will only show planets as a  fuzzy blob of false color and it might even turn your hair and face permanently purple if you look at Jupiter through one. However, even with the CA, I find that the AR152 gives nice sharp views of the Moon and planets.  The planetary views are definitely not as nice as you would get with an apo, but they’re not darned bad either. With that said, if the Moon and planets are your primary interest and you want every last possible detail, then you should be looking at other telescopes.  But don’t be fooled into thinking that an achromat cannot give a decent view of these objects with plenty of high contrast detail.

On nights of good seeing I’ve had very good views of Jupiter up to 300x and regularly use a 4.5mm Meade 5000 HD-60 on the giant planet giving 220x.  The GRS is an easy target for the AR152 as are larger barges and festoons.  The CA on Jupiter is obviously about as bad as it gets.  The planet exhibits a bluish halo around it that extends out from the planet about 1/2 the planet’s radius. The belts and zones on the planet also appear more of a grayish color instead of their natural reddish brown.  However, the belts and features on the planet are very crisp and sharp with loads of detail during moments of good seeing.

Open Clusters

Open clusters are definitely the AR152’s strong point. I would even go as far as to say that the AR152 has given me a new appreciation of these celestial wonders.

The double cluster in Perseus is especially beautiful in the AR152.  Using a 38mm Orion Q70 eyepiece both clusters are framed beautifully and show sharp pinpoint stars from field stop to field stop.  At a club observing event back in November 2012 the owner of a Meade 12″ SCT even commented that the double cluster looked much better in the AR152 than in his 12″ SCT.

The Wild Ducks cluster (M11), M46, M35, and M7 are all wonders to behold in the AR152. M46 looks like fine grains of sand scattered across a velvety black background with the small planetary nebula NGC 2438 easily visible; even from my light polluted backyard.

The bright stars in M45, the Pleiades, do show a slight amount of CA in the AR152, but it’s not objectionable.

Globular Clusters

The AR152 provides fairly good views of globular clusters. Six inches of aperture seems to be kind of the magic aperture where globular clusters really start to resolve.

M13 and M15 show many resolved stars in the AR152, whereas my 4″ achro shows these clusters as fuzzy patches with a few stars here and there.  My 10″ Dob; however, shows many more stars than the AR152. The dark propeller feature in M13 is detectable in the AR152 at around 140x, but it takes some work — this is normally an easy feature in my 10″ Dob.

Nebulae

M42 is spectacular in the AR152; as it is in just about any telescope. Six inches of clear aperture is enough to start showing actual structure in the nebula.  The E and F stars in the trapezium are fairly easy at around 90x on nights of good seeing.  Using an Orion 38mm Q70 or an ES 82 degree 24mm eyepiece gives a very beautiful high contrast low power view of the nebula.  The view has an amazing 3-D like effect.

M17, the Swan Nebula, is also a nice target in the AR152.  The “number 2” shape of the nebula is very prominent and stands out well in the AR152.

From a dark site NGC 2024, the Flame nebula, is an easy target for this scope showing the prominent dark lanes often referred to as the “tank tracks”.

M57, the Ring Nebula, easily shows its oblong ring shape with a few glimpses of structure visible. It doesn’t have quite the same “pop” as it does in my 10″ Dob, but it’s still nice.

Galaxies

To be honest I’m not that much of a galaxy hunter. If I plan on hunting down dim galaxies I typically pull out my 10″ Dob.  The only galaxies that I’ve viewed with the AR152 are M31 along with its companion galaxies and M33.  M31 honestly doesn’t look much different than it does in my 10″ Dob from my backyard.  M32 and M110 are both visible in the same field of view as M31 and nicely framed using a 38mm Q70 eyepiece. M33 was just a smudge of light and would have been difficult to detect had I not know what I was looking for.  One of the spiral arms of M33 is discernible from my backyard using my 10″ dob, but no such structure is visible with the AR152.

Update: 4/01/2013

I recently took a look at the M81/M82 galaxy pair with the AR152 from my backyard and must say the scope performed very well on these bright galaxies. Both galaxies fit nicely in the field of view of an ES 24mm 82 degree eyepiece.  The oblong round shape of M81 and the ragged cigar shape of  M82 were readily apparent. Increasing the magnification doesn’t really reveal much more detail on M81, but on M82 the ragged edges of the galaxy show some interesting detail. I was able to increase the magnification to 147x using an ES 6.7mm 82 degree eyepiece and still have plenty of light.

Conclusion

If you are looking for a well made large refractor but don’t want to take out a second mortgage on your house, then the AR152 may be the telescope for you. It’s certainly not a premium grade refractor, but at its price point I don’t think you’ll find a better built 6″ refractor. It really is an amazing package considering what you get for your money. For $750 you get a large refractor that is ready to go right out of the box without a lot of upgrades such as a better diagonal and focuser. The only component I felt the need to upgrade was the finder, but that’s personal preference — I’m not a fan of straight through finders.

With 6″ of clear aperture the AR152 is an excellent deep sky performer, especially on open clusters, and performs pretty well on planets too if CA doesn’t bother you too much. If CA is an issue for you, then you should steer well away from this telescope.

Overall I’m very happy with the AR152 — there’s just something magical about a large refractor.

This entry was posted in Telescope Reviews and tagged , , , , , . Bookmark the permalink.

41 Responses to Review – Explore Scientific AR152 Achromatic Refractor

  1. Thanks for the review of the AR152. I’m also considering purchasing this scope and your article had the level of detail that I needed for this scope. Currently I have a 102mm refractor and 10″ dob but I was looking for something in between.

    • Michael Wood says:

      Thanks for your comment James. The AR152 has become my most used telescope. I find it to be very versatile — it’s very good at low power wide field views, but you can also push the magnification when you want to. I really like my 10″ dob too, but I just find the AR152 more fun to use.

  2. Mark says:

    Thank you for your honest review (regarding ca..) of the es 152 refractor, aim currently awaiting delivery of this telescope and I agree with you that ther is just something so special and appealing about using a large refractor. Ian thinking about using this scope on the new celestron vx go to mount.

    • Michael Wood says:

      I think you will love the scope as long as you understand it’s limitations. The new VX mount is supposedly a little sturdier than the CG-5, so I think it should handle the scope with no problems. I eventually ditched my 16″ mount extension because the slightest breeze would cause a lot of movement because of the long moment arm. So if you’re thinking about a mount extension, don’t waste your money on the Orion 16″ extension. Too bad they don’t make an 8″ mount extension; that would probably be perfect.

      • Mark says:

        Hi mike , I plan to observe the moon and Jupiter as well as Saturn with this scope, as for star clusters and deep space could you please recommend which mag eye pieces would suit?? Also does it make a big difference if I use 1inch or 2 inch eyepieces

  3. Michael Wood says:

    It really depends on the particular star cluster you’re viewing. For larger clusters like the Double Cluster, M45, M44, M7, etc. I stick with low power 2″ eyepieces. My 24mm 82 degree Explore Scientific is probably my favorite eyepiece for large extended objects. Low power wide field eyepieces are also really good for large galaxies like Andromeda and M33. For smaller clusters like the Wild Ducks Cluster (M11), I typically use 1.25″ wide field eyepieces in the 14mm – 11mm range. I use wide field eyepieces for pretty much everything except for my highest power planetary eyepieces which consist of a 5mm AT Paradigm and a 4.5mm Meade 5000 HD-60. I really like the Meade HD-60 for high powers — it’s very sharp.

    As far as 1.25″ vs 2″ goes, 2″ eyepieces are the only way to get larger fields of view after a certain focal length is reached. For instance, in order to get the 82 degree field of view ES has to start making the eyepieces in the 2″ format starting with the 18mm. However, the same 18mm with a 68 degree field of view could still be produced in the 1.25″ format. So basically 2″ eyepieces are sometimes required to get the larger fields of view. IMO, you should have at least a couple of 2″ wide field eyepieces in your kit. The 24mm and 30mm ES 82 degrees are really nice 2″ eyepieces and a lot cheaper than the Televue 82 degree Naglers.

  4. Mark says:

    Hi mike thanks for your reply, iam still currently awaiting delivery of the es 152 and I am having this scope imported from the European distributers in Germany as it is not currently sold in the uk. I am really only a beginner when it comes to observing and this will be the telescope I really hope to grow with,also along with the vx mount its going to be an early 50th birthday present (wife just beginning to accept that) .thanks for the advice on eyepieces I will defiantly purchase a couple of wide angle 2 inch along with a minus violet filter and maybe a nebular filter. Iam really looking ford to observing the Orion Nebula and the Pleiades cluster but will have to wait a few months till they come into view . Until then I have the book turn left at Orion to help me learn about what I hope to see using the go to mount and its in built database. Cheers,,, mark.

  5. Mark says:

    Hi Mike, hope you don’t mind me letting you know that I received my es 152 albeit with a badly scratched finderscope, (it’s a wonder that the main optical tube was scratch free) It got me to wondering if the lens may be out of collimating due to bumps in transit and would therefore be very gratefull if you could give me some pointers on how to check . I realise that I will need a collimater for refractors and am wondering which is the best one to buy, I hope to take delivery of the vx mount in a couple of weeks and thought that I could do a collimating check in the meantime, so to have it up and ready for observing. Regards Mark.

    • Michael Wood says:

      Congrats! Sorry to hear about the in transit damage. If your collimation is way out then you should be able to tell by defocusing a star and looking at the ring pattern. If the ring patterns aren’t nice and concentric around a central point, then your collimation is out. Also, in focus stars at high power will show diffraction rings skewed to one side of the star. To collimate the scope you’ll need a refractor collimating eyepiece. Just do a Google search for refractor collimating eyepiece and you should be able to find plenty. The one I used came with my Celestron Omni XLT 102 refractor.

      To collimate you insert the 1.25″ EP adapter from your diagonal into the the scope where the diagonal usually goes, then insert the collimating eyepiece into the adapter, and then shine a bright light into the hole on the side of the collimating eyepiece where the reflective material is (you must have the front lens covered when doing this). Looking through the collimating eyepiece you will see a donut reflection from the objective lens. If you see a second donut reflection overlapping or completely separate from the one in the center, you adjust the lens cell until the second donut merges into the one in the center. Before adjusting the lens cell make sure the focuser is mount square all the way around the tube. If the focuser is not mounted flush all the way around, it will cause a misalignment.

      I would do a Google search for collimating a refractor before attempting. There are some articles out there that explain it a lot better than I can.

  6. Mark says:

    Thanks mike for your reply, i found your description of how the collimating device works (shining a bright light into the side hole of collimating eyepiece) very helpfull and now feel confident knowing how the process works. Thanks again. Mark Laitak.

  7. tony says:

    I am very new at this and the second scope I bought was ES152. I was very surprised at the Quality for the price. Being a new guy I accidently left my2″ Semi APO filter on the diagonal (witch did nothing for me anyway)when I added a 1.25 Fringe buster to an EP. Maybe because i do not know any better. But it was the best view I ever had with the 152 Do you think it is just my emagination

    • Michael Wood says:

      Probably not your imagination. The Semi APO is a combination of the Fringe Killer and the Moon and Sky Glow Filter, so the combination you used is the same as if you had 2 Fringe Killers and and a Moon and Sky Glow all stacked up. This combo would probably cut way back on the CA visible around bright objects, but for deep sky, it would probably dim the view a little too much. Next time you’re out with the scope do some comparison tests and go with what you like best — there is no wrong answer.

      Check out these articles by Neil English about filters:

      http://neilenglish.net/further-adventures-with-filters

      http://neilenglish.net/taking-back-visual-astronomy-filters-ii/

      • tony says:

        Michael Thanks for the links I will keep at it .I was also comparing filters on tree tops about 2 miles away

  8. jimnc says:

    OK I have read many reviews on line and comparisons to other similar OTA’s. It was this written review that helped me make my final decision to buy one. Thank you for writing it. Much appreciated and a job well done sir.

    Jim

    • Michael Wood says:

      Thanks for the complements Jim! I’m glad you found the review helpful. Enjoy the new scope! 🙂

  9. M42 says:

    Thanks for your candid review. Do you know how deep space views of this scope compare with an 8″ SCT or the ES 127 ED? I have the SCT and have difficulty seeing galaxies like M82, which you obviously had no problem seeing with the AR 152. Have wanted a refractor for a long time and am torn between the 152 and 127; hoping you might be able to shed some light. Thanks.

    • Michael Wood says:

      Hi and thanks for reading! The view compared to an 8″ SCT is very similar with a slight edge going to the refractor, but that’s subjective of course. The one thing these refractors can give you that no SCT can is very wide and bright low power views. I was looking at Antares and M4 in the same lower power field of view the other night and it was beautiful.

      I haven’t compared directly with a 127 ED, but have compared with a 120 ED. Under dark skies the extra inch of aperture makes a noticeable difference on DSOs — not so much under light polluted skies. The AR-152 is obviously not optimal for planets, but I look at planets with it quite a bit anyway. Saturn appears very crisp, but it looks very yellow, whereas in an ED scope it looks more tan or off-white. I suspect the 127 ED would be the all around better scope if you want to do some serious planetary observing.

      With all of that said, if you’re not happy with the views of galaxies you’re getting with your 8″ SCT, you won’t be happy with either of the refractors either. I would suggest a 10″ or 12″ dobsonian if you want to improve your view of galaxies. Or if you’re like me and hate dobsonian mounts then maybe a C11. Keep in mind that dark skies are essential for viewing galaxies. My AR-152 shows better views of galaxies from a dark site than my 10″ dob does from my house. From a dark site, the AR-152 will show subtle spiral structure in M51 and the dark lane through the center of M104.

      Good luck with your choice!

  10. M42 says:

    Thanks for replying so fast. I don’t do much planetary viewing and really am interested more in deep space, nebulae, galaxies, clusters. In dark skies the SCT just doesn’t show many of the galaxies or nebulae at all or with averted vision. I’ve read where some have said a 6″ refractor has outperformed their 9.25 SCT. I hate to go to an 11″ or 14″ because of the weight issue. I may try out one of these refractors and see how they do.

    Do you have a recommendation for a compatible goto mount? Thanks.

    • Michael Wood says:

      I could definitely see these scopes being comparable to a 9.25″ SCT. An 8″ SCT does seem to have a slightly darker image than these scopes. I usually never say this though because people who have never used one of these scopes will quickly shoot you down for spouting such heresy, but that has been my experience. For a mount, the Celestron Advanced VX would be fine for visual use — expect a little shaking while focusing though. If you want to do photography, you’ll need at least an Orion Atlas or Celestron CGEM. Personally, I’m thinking about upgrading to an Atlas Pro AZ/EQ-g so that I can use the scope in alt/az mode.

      • Anonymous says:

        You may also like to use the Ioptron iEQ45 with the AR152 light weight and does a fantastic job. Image or visual.

      • Michael Wood says:

        I’ve considered the iEQ45. I just don’t have any experience with iOptron equipment.

  11. Anonymous says:

    Hi mike ,just to let you know , I now have the es 152 on the celestron vx mount and this mount seems fine for this scope ,but it does definitely require an additional 11lb counterweight to handle the es 23 lb weight. I have also purchased 2 es 82 degree eyepieces 28 mill and 11 mill ,although I have not yet had a chance to really appreciate them because of continuous cloudy weather ( curse of the new scope). Hope to update you soon. Mark.

    • Michael Wood says:

      Great to hear! I think you will really enjoy those eyepieces. I’m glad the mount worked out well for you too — I wish I had the AVX instead of the CG-5.

  12. M42 says:

    Thanks for your helpful review and for answering my questions so fast. I’ve got one of these ordered and on the way. I’m going to try keeping a Baader Fringe Killer in the diagonal and also stack a Baader Moon and Skyglow on top of it when viewing planets or the moon. From what I’ve read stacking the Skyglow will remove the yellow tinge and restore neutral colors.

    Can’t wait to try it out on deep space.

  13. M42 says:

    I love the ES 82 deg eyepieces – to me they are a poor man’s Nagler. I’m looking at either adding an 18mm or 24 to my collection. Do you have any recommendations as to which one would work better with this scope? I’m leaning toward the 18 because with the magnification being only 988 it seems the fov should be wide enough. What do you think?

    • Michael Wood says:

      I have the 18mm and the 24mm the 18mm is okay, but I don’t think it’s quite as good as the 24mm. The 24mm has better edge correction and is my most used eyepiece. I only use the 18mm every once in a while.

  14. I’m seriously thinking about dumping my R200SS and getting an AR152. I would, however, keep the GPDX mount. What are you latest thoughts on your scope?

    Philip Neidlinger

    • Michael Wood says:

      I still like the scope, but I haven’t been using it as much since I purchased an ES ED127. I find that the ED127 is slightly better on most objects than the AR152 — stars will focus a little tighter/cleaner with the ED127. I still pull out the AR152 when I want to view galaxies though.

  15. Mike, thank you for maintaining this thread on the review of the AR152. I was the first to make a comment on this review back in March but with a 10″ dob and 102 mm Refractor and a Celestron C-9.25 in my arsenal I was reluctant to pull the trigger on the purchase of the AR152 but with the price increase of $100 by Explore Scientific it is time (not happy about the $40 – $100 increase in ES EP’s). I have a story about why you shouldn’t buying a scope off ebay (C-9.25) but that is for another time. Thanks for providing such a great review and the input about the use of the fringe killer filters. I’m waiting for High Point Scientific to deliver my new scope and I’m matching it with a CGEM mount. Thanks again.

  16. Sanjeev Moudgil says:

    Great review friend….I need your advice as I am looking for an 4″ refractor and confused between nexstar102 slt and ES ar102, I know the limitations of a 4″ and my main thrust is on solar system and DSO and to some extent Galaxies but I want to see some details on mars so please guide me according to your experience which is the better one in this price range. I am from india and don’t have many scopes available here so your help.will be highly appreciated.
    King regards

    • Michael Wood says:

      Of those 2, I would recommend the ES AR102. The ES scope has a slightly longer focal length and is better mechanically. However, if you go with the ES scope, you will also need to buy a mount. With that said, I would recommend the Celestron Omni XLT 102 over both of these scopes if you can get one in India. The Omni 102 has a longer focal length which helps on cutting down the CA on planets. The Omni also comes with a good equatorial mount. It doesn’t have GOTO, but it’s a solid mount and tracking is easily added.

      • Sanjeev Moudgil says:

        Oh thank you so much!! Yes omni xlt was another one which I was thinking and I believe u too have one of these I saw that standing by AR152 … : ) I hope keep getting your valuable advice and comments…Thanks again and Good luck !!

      • Anonymous says:

        Hello mike, i have been looking to buy an ar 152 chromatic as the price is brilliant compared to the one i would really like and that is the apm 152 doublet apo. What would the differance be looking at the same object with the same eps with these 2 scopes. The prices are worlds apart but os the viewing. Tha ks for your time MIke amd really appreciate your time a d effort i helping novices like me. Regards

      • Michael Wood says:

        In my experience the AR152 is about equivalent on deep sky objects to a 5″ apo. However on star clusters I find the 5″ apo to still give somewhat better views than the AR152. I don’t have any experience with 6″ apos, so I’m not sure how this scope would compare to the APM 152; however, Karl Krasley did a great reveiw of the AR152 and actually compared it to a 6″ APM Apo in the review. Here is a link to the review if you haven’t seen it yet: http://www.cloudynights.com/item.php?item_id=2051

  17. Pingback: Choosing a new mount - Page 2

  18. Jon says:

    Hi, I enjoyed this review and the review of your ES 127ED apo. I’m wondering about something – how low of a magnification can these scopes go? I’m particularly interested in the AR152 due to the nice low price, and I’m a fan of widefield viewing. I currently have an ST-80 as my widefield scope, and I love it. I can sweep around with a humble 32mm Plossl at 12x with an almost 4-degree FOV; it’s like ultrasteady big binoculars, as far as I’m concerned. I mostly use a 25mm Plossl instead at 16x and 3.25 degrees because the 32mm gives me a 6.4mm exit pupil that’s too large for my older eyes, and there’s no need to waste light.

    Plugging some numbers into a spreadsheet, it looks like the 68 degree ES 40mm would give you about the maximum FOV in the AR152, about 2.8 degrees at 24x, which would be really nice. (I have a Celestron Luminos 10mm 82-degree eyepiece, and I’m not a big fan of the really widefield views it gives.) Is there some lower limit on magnification in refractors?

    • Michael Wood says:

      Hi Jon, glad you enjoyed the review. The exit pupil of an eyepiece will be the limiting factor on how low you can go in magnification. The lower the magnification, the larger the exit pupil. The largest useful exit pupil is around 7mm (the diameter of the fully dilated pupil of a young healthy person, it gets smaller as you age). The formula for calculating exit pupil is APERTURE / MAGNIFICATION = EXIT PUPIL. So, if yo solve the formula for magnification with a 7mm exit pupil with the AR152, you end up with a lowest useful magnification of 21.7x. This scope won’t go as low or wide as your ST80, but it’s still decently wide. With reflectors you run into a lower magnification limit because of the secondary mirror, once you get low enough in magnification the shadow of the secondary mirror becomes visible. There is no such limitation with refractors since there is no secondary. Hope that helps. 🙂

  19. Don says:

    How is this scope for deep space Astro photography ? Thanks

  20. John R says:

    Sounds like a great scope. I read your comments on the Double Double in Lyra. You didn’t mention if you saw any Airy disks. I presume that if you can split them clealy then the disks would be there, but my 10″ Dob can barely split but never shows the disks.
    Thanks
    John

  21. Venus says:

    Skype has established its website-centered customer beta on the world, after starting it broadly
    from the Usa and You.K. previously this 30 days.
    Skype for Online also now supports Chromebook and Linux for instant
    online messaging communication (no voice and video yet, those
    call for a plug-in installation).

    The expansion in the beta contributes help for a longer listing of dialects to
    help reinforce that global functionality

  22. Luca says:

    Hi, Thank you for the great review. I am looking for a scope for lunar imaging. I would use a mono camera and can use narrow band filters to cut down CA and AD. I have a 80mm triplet for DSO imaging and I am afraid I felt in love with refractors. Unfortunately I can’t afford a large apo just for lunar imaging. So, those large achromatic are really tempting….. I have tried to convince myself on a 8” Newtonian but I always end up to the fracs …. I would be grateful for an opinion on this scope for lunar imaging.
    Clear skies,

    Luca

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s