Covey32
professor emeritus
Reged: 12/09/04
Posts: 613
Loc: Georgia
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Why no reviews anywhere about this scope?
Seems strange....Nobody bought any ?
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Hank
12.5" Mag1 Portaball
Orion 120mm F5 Refractor
Skywatcher 120ED F7.5 Refractor
1982 Celestron C8 Orange tube
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ForgottenMObject
Post Laureate
Reged: 09/11/04
Posts: 3581
Loc: Maryland, US
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They are brand new - you probably have to wait a bit to see some reviews.
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Matthew
IDA member
XT8i, 10x50 binoculars, lots of eyepieces
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Clive Gibbons
Mostly Harmless
Reged: 05/26/05
Posts: 9785
Loc: Oort Cloud
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Quote:
Why no reviews anywhere about this scope?
Seems strange....Nobody bought any ?
These are made by Synta and also sold as Sky-Watcher 150mm Maksutovs. A friend of mine owns one and is quite happy with it.
One caveat: The actual aperture of the 150mm is approx. 142mm. This is because the primary mirror is slightly smaller than necessary to deliver a full 150mm clear aperture (entrance pupil) at the corrector lens. The 127mm Mak suffers from the same issue. It's "entrance pupil" aperture is 121mm, as measured by Sky and Telescope magazine in their March 2002 review.
Cheers,
Clive.
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A few telescopes of dubious value.
Understanding wife and three curious cats.
"Semper ubi sub ubi"
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southmike
Carpal Tunnel
Reged: 11/22/04
Posts: 2819
Loc: Fayetteville, NC
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this is the closest review i have seen
Quote:
Well it turned out to be clear tonight so I got the scope out for a test. Jupiter was too low in the sky to view well so I had to go with the double-double in Lyra as my primary test subject. I was able to use Jupiter to check image shift though. At 450x the shift was about 1/2 diameter of the planet. I'm sure someone else can figure out the math behind that and what it really means but for me it was just my observation. The double-double split very nicely at 200x but I could tell that it would be a lot cleaner if I adjusted the collimation. I started that process with some success but by 11pm the mosquitoes were so fierce that I had to pack it in for the night. At this point I find the scope to be very similar to the Orion 127 Mak I had before with the benefit of more aperture. I plan on doing a side by side comparison with my Meade 127ED/APO once the collimation is to my liking and will make a report of my findings.
Greg
just curios do you know the actual view of a nexstar 5?
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group scope pic
my refractors
LX200 10"-St120
LX200 8" f6.3-Orion 80ed
LX200 8" f10-Orion 90 Mak setup pic
Meade 102ED LXD650
Sky Watcher 100 ED Triplet prototype
Nexstar 5
etx125
etx70's
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Starman1
Postmaster
Reged: 06/24/03
Posts: 10837
Loc: Los Angeles
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Another competitor of this new scope is the Celestron C-6 Schmidt-Cassegrain, which has a shorter f/ratio and a wider field of view. Price is similar, but a little less for the Celestron.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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Kenny
professor emeritus
Reged: 07/04/05
Posts: 537
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Quote:
Why no reviews anywhere about this scope?
Seems strange....Nobody bought any ?
I'm not aware of any full reviews, but there are a few older threads on CN about this scope. As I mentioned in one of these older threads, there is a used Skywatcher version at Kendrick's (used price already reduced!) if anyone is interested.
Ken.
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Greg W
member
Reged: 02/26/05
Posts: 28
Loc: Wales, Maine
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Quote:
this is the closest review i have seen
Quote:
Well it turned out to be clear tonight so I got the scope out for a test. Jupiter was too low in the sky to view well so I had to go with the double-double in Lyra as my primary test subject. I was able to use Jupiter to check image shift though. At 450x the shift was about 1/2 diameter of the planet. I'm sure someone else can figure out the math behind that and what it really means but for me it was just my observation. The double-double split very nicely at 200x but I could tell that it would be a lot cleaner if I adjusted the collimation. I started that process with some success but by 11pm the mosquitoes were so fierce that I had to pack it in for the night. At this point I find the scope to be very similar to the Orion 127 Mak I had before with the benefit of more aperture. I plan on doing a side by side comparison with my Meade 127ED/APO once the collimation is to my liking and will make a report of my findings.
Greg
Follow up to my initial posting. The scope did not compare well to the Meade 127ED. The 150 Mak had a brighter image but was no where near as sharp as the 127ED. I tested the 2 scopes on Jupiter, Mars and several stars/doubles. The 150 Mak also had something I had never seen in any scope before. As a bright object such as Jupiter was coming into the field of view there was a large loop of light that filled the view and gradually went away as the object moved towards the center of view. Although my mount tracks and I do not need to worry about anything moving across the field of view, I felt it would certainly be bothersome to someone without tracking. I was able to collimate the scope very easily but it just never reached the level of quality I had hoped for. I sent the scope back.
Greg
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Ken603a
sage
Reged: 05/06/05
Posts: 445
Loc: Texas, USA
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My Mak 102 has this loop of light on the very edge as the object moves into the view, but as soon as the full object is viewable it fades away. It hasnt stopped me from enjoying the Mak. Perhaps this is a general MAK issue?
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Happy Skies!
10 X 50 binoculars
Orion MAK 102 EQ with 6X30 RACI finder and home built zero finder.
10" X-Class DOB 9 X 50 RACI finder.
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Greg W
member
Reged: 02/26/05
Posts: 28
Loc: Wales, Maine
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Quote:
My Mak 102 has this loop of light on the very edge as the object moves into the view, but as soon as the full object is viewable it fades away. It hasnt stopped me from enjoying the Mak. Perhaps this is a general MAK issue?
That is a possibility but I never had this with the 127 Mak I owned previously. For $650 I think the scope is still a good deal, but I was hoping for something to replace the large set up I have now. I guess I will just keep what I have now even though it is a little bulky.
Greg
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mooreorless
Carpal Tunnel
Reged: 07/05/05
Posts: 1512
Loc: Cornpropst Mills,Huntingdon,Pa
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Hello Fellows,I'm no expert but on Amart a fellow had trouble with halo of light around planets etc. with an Orion 102 Mak and they told him to stop down aperture with 1/4 inch to 1/2 inch mask to test for turned edge.Something to try.But then if you are happy with the Mak why bother.Cheers.
Steve M
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Regards,Steve M
"the eights are better" Jim Carmichel of Outdoor Life magazine
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Ken603a
sage
Reged: 05/06/05
Posts: 445
Loc: Texas, USA
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Turned edge? Sounds like something that needs to be fixed by a manufacturer... Mine doesnt seem as bad as Greg's problem, but I would like to have the scope in the condition it is intended to be in. I may call Orion and see what they say...
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Happy Skies!
10 X 50 binoculars
Orion MAK 102 EQ with 6X30 RACI finder and home built zero finder.
10" X-Class DOB 9 X 50 RACI finder.
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Larry F
Pooh-Bah
Reged: 05/24/04
Posts: 1330
Loc: Westchester, NY
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Inadequate length of dew shield, permitting reflections of bright objects from the corrector plate even though they are off axis?
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C5 Orange Tube SCT
Orion 127 Mak
SV Nighthawk (1st generation)
CPC 800 XLT SCT
Coronado Maxscope 40
Denk II Binos
Giro 2/Tech2000 Giro Driver/Tech2000 QuickDraw Pier
A zillion eyepieces and some more mounts
Mason & Hamlin BB 214 cm (piano)
My Gallery
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Starman1
Postmaster
Reged: 06/24/03
Posts: 10837
Loc: Los Angeles
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Quote:
Hello Fellows,I'm no expert but on Amart a fellow had trouble with halo of light around planets etc. with an Orion 102 Mak and they told him to stop down aperture with 1/4 inch to 1/2 inch mask to test for turned edge.Something to try.But then if you are happy with the Mak why bother.Cheers.
Steve M
The mirrors on Orion's Maks are undersized, i.e. the light that passes through the edges of the corrector lens misses the edge of the mirror. A 1/2" wide annulus around the front of the corrector would only eliminate the very edge of the primary mirror (if it is the cause).
I've thought about it, and I think two things may be happening:
1) the light bent outward by the outer edge of the corrector may be reflecting from the side of the tube into the light path. This would be more severe the farther off-axis the image was, which seems to be the case.
2) There is inadequate front-end baffling of lateral light coming into the scope.
#1 could be solved (with some difficulty) by flocking the inside of the tube and outside of the primary baffle.
#2 could be solved with a dewshield of 6" length that is very unreflective internally.
Alternatively, the corrector might be filthy and scattering light. The eyepiece may be dirty and doing the same.
But I'd bet on light scatter in the tube, simply because I saw such a huge difference when I flocked my SCT, which doesn't cause the entering light to diverge as much as a Mak.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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mooreorless
Carpal Tunnel
Reged: 07/05/05
Posts: 1512
Loc: Cornpropst Mills,Huntingdon,Pa
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Hi Larry and Don,I am lucky I have a dark site here and am not bothered with stray light.I have to remember to think of the easy fixes,but then these fellows should already have dewshields.
Steve M
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Regards,Steve M
"the eights are better" Jim Carmichel of Outdoor Life magazine
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DIO
super member
Reged: 11/12/04
Posts: 101
Loc: KY, USA
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Guys, I have already mentioned and solved this problem. I have an Orion 90mm Apex.
Master Pensack  has caught the root cause: The bright loop of light is eliminated if you put flocking paper in the inside of the tube - the small tube which goes through the primary mirror. It appears that this problem is very frequent in the Orion Maks. Nothing to do with the optics.
For those interested in the history of this, look under my name in a previous CAT thread - sorry I cannot post the link right now, but I don't have many entries at CN anyway, so it's easy.
Cheers,
Dimitri
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DIO
super member
Reged: 11/12/04
Posts: 101
Loc: KY, USA
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By the way, before that, I tried:
- Dewshield: No good.
- Flocking primary tube: No good.
- Masking the external ~0.5 inch (the stopping solution discussed above): No good.
- Masking/covering/flocking the shiny metallic parts which hold the corrector lens in place: No good.
So, effectively I took the scope apart and put it back together about a dozen times until the problem was identified and solved. And it was with the help of another CNer, who suggested a specific test.
Cheers again,
Dimitri
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stevie
Spiderman
Reged: 12/07/03
Posts: 3135
Loc: Belgium
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you can read more about it here
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stephane
Our shots(updated :18.02.2008)
My videos
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mooreorless
Carpal Tunnel
Reged: 07/05/05
Posts: 1512
Loc: Cornpropst Mills,Huntingdon,Pa
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Hi Dimitri,This is wild some of the things that you can do to fix scopes.I told the guy on Amart about this and he is going to try to do it but is worried to take his scope apart.Clear Skies.
Steve M
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Regards,Steve M
"the eights are better" Jim Carmichel of Outdoor Life magazine
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DIO
super member
Reged: 11/12/04
Posts: 101
Loc: KY, USA
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Clear skies to you too Steve! And good to hear from you again Stephane! Thanks for posting the link. All, it was Stephane's test which helped solve the problem!
Dimitri
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Starman1
Postmaster
Reged: 06/24/03
Posts: 10837
Loc: Los Angeles
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Steve,
This mod can be done without taking the scope apart.
Roll up the flocking paper(don't remove the backing--you're not gluing it in yet) into a tube slightly smaller than the inside diameter of the primary mirror's baffle.
When you insert it in the back, it will unroll until it fits the inside of the baffle tube fairly snugly.
Make certain it is not long enough to stick out the front of the baffle tube.
Star test the scope. Eliminate the problem? (Sounds like it might be yes).
Remove the rolled-up flocking paper and be certain it is exactly the length/width to go around the inside of the baffle WITHOUT OVERLAP. Remove the backing, and roll the tube until it just barely overlaps. Insert the tube into the baffle(try very hard not to hit the sides of the baffle tube when inserting). Insert a piece of wooden or plastic doweling slightly smaller than the I.D. of the baffle tube and roll it around the perimeter of the baffle to press the flocking paper in place.
If this seems to be difficult because you doubt you can stick it in without touching the sides of the baffle, then before you pull the backing paper off the adhesive, cut it into two strips and put one strip in first, then turn the scope over and put in the other strip. Remember: NO OVERLAP. The adhesive sticks very well to metal, but not to the fuzz on the top of the flocking paper itself.
So, no dismantling necessary.
Good luck.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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mooreorless
Carpal Tunnel
Reged: 07/05/05
Posts: 1512
Loc: Cornpropst Mills,Huntingdon,Pa
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Hi Don,Thanks for taking the time to post this information on how to do this,I'm sure it will help this guy a lot.I have been checking out Cloudy Nights for a good while and finally just signed up recently.I just never took the time to do it.The baffle on these Orion scopes must be a pretty bright finish to cause this much problem,well I guess it doesn't have to be that bright that is why they make flocking paper.Once again Thank You, Dimitri and Stephane.I'll let you know how he made out or better yet have him tell you.
Steve M
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Regards,Steve M
"the eights are better" Jim Carmichel of Outdoor Life magazine
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stevie
Spiderman
Reged: 12/07/03
Posts: 3135
Loc: Belgium
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glad to be of service
hello again Dimitri 
so it seems everything worked out for you ? 
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stephane
Our shots(updated :18.02.2008)
My videos
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tolmac
journeyman
Reged: 07/31/05
Posts: 7
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Just curious Greg, was the Mak properly cooled when you tested it against the Meade 127?
Also, I've found that the primary in the Orion Maks are not under sized according to my tests using a laser perpendicular to the meniscus. The light beam hits the primary as soon as it passes the edge and enters the light path. I could not detect any light going past the primary. Just musing.
Tony
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102/F5
150 Mak
AstroView EQ/HEQ5
15x70 bino
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Starman1
Postmaster
Reged: 06/24/03
Posts: 10837
Loc: Los Angeles
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Quote:
Also, I've found that the primary in the Orion Maks are not under sized according to my tests using a laser perpendicular to the meniscus. The light beam hits the primary as soon as it passes the edge and enters the light path. I could not detect any light going past the primary. Just musing.
Tony
The steeper the curve, the more divergeance it has. Meade makes a point of using an 8" primary on their 7" Mak.
The entrance pupil is the diameter of the corrector, but to field that light does require a primary larger than the corrector.
How much larger is a calculation an optician should be able to provide.
Your laser should not be perpendicular to the corrector's surface, but its beam should be parallel to the tube for On-axis rays. Tilt the laser slightly sideways to simulate off-axis rays.
In my Orion 127 Mak, a laser beam shone into the tube , kept parallel to the tube, hits the edge of the primary mirror well before the beam gets to the edge of the corrector, indicating that the undersized primary significantly vignettes the light from the edge of the corrector. It's difficult to evaluate perfectly, but it appears that the amount of corrector that actually casts its light on the primary mirror is less than 120mm.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
Edited by Starman1 (07/31/05 02:04 PM)
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tolmac
journeyman
Reged: 07/31/05
Posts: 7
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Perpendicular to the corrector is the same as parallel to the tube I would think, but I didn't allow for stray light and didn't angle the laser because stray light hinders the image, doesn't it? It's not something we want, is it? The beam hit the primary even before it left the useless beveled inner edge of the corrector and I double checked my test rig for squareness.
I would be interested in getting some of the pro-optitians involved in this.
Your response was greatly appreciated.
Regards,
Tony
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102/F5
150 Mak
AstroView EQ/HEQ5
15x70 bino
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Starman1
Postmaster
Reged: 06/24/03
Posts: 10837
Loc: Los Angeles
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Perpendicular to the plane of the corrector would be parallel to the tube, but perpendicular to the surface of the corrector would be substantially angled. That's why I made the clarification.
I had the back of the tube open and a bullseye there. When the laser beam hit the middle of the bullseye, I knew it was "on-axis".
I moved the beam sideways toward the edge of the corrector, keeping the beam centered in the bullseye on the rear of the scope. The beam reached the edge of the primary mirror several mm before it reached the edge of the clear aperture of the corrector.
My corrector is 124mm wide in clear aperture, and the beam hit the edge of the primary mirror about 4mm in from the bevel on the edge of the corrector (116mm diameter, or 58mm radius). At the edge of the usable corrector (124mm diameter), the beam hit the inside diameter of the tube, reflected off the tube onto the mirror as a diffuse beam and put enough light on the rear-mounted bullseye to see. This is proof-positive the inside of the tube is too reflective and can cause a glow in the field of view when viewing bright objects, even on axis. This would be even worse for off-axis light rays.
If the bullseye technique is not good enough to guarantee perpendicularity of the beam to the plane of the corrector, I'll allow a little "fudge" factor and call it a 120mm scope.
At 1540mm of focal length, that makes the f/ratio 12.8 to 13.3 depending on the accuracy of the bullseye method, but definitely not f/12.1.
IMHO, Orion should not advertize this as a 127mm aperture.
I am going to presume their "150mm" aperture is similarly smaller than its true effective diameter, but by how much, I do not know.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
Edited by Starman1 (07/31/05 07:39 PM)
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Greg W
member
Reged: 02/26/05
Posts: 28
Loc: Wales, Maine
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Quote:
Just curious Greg, was the Mak properly cooled when you tested it against the Meade 127?
Tony
Yes. The Meade also takes a while to calm down. The scopes were out for about 2 1/2 hours.
Greg
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Dylan Gladstone
scholastic sledgehammer
Reged: 08/05/07
Posts: 912
Loc: Connecticut, USA
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Thanks for this thread everyone!
I have that same "loop of light" when a bright object is just out of the field of view with my 127 Mak. I was considering dismantling the scope to flock the inside. Searching on "flocking" and "127 Mak" I came across this thread.
I'll try just flocking the inside of the baffle using Don's instructions.
Will this also increase contrast a bit?
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Orion SkyView Pro 127mm Maksutov
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bobmarleyou812
member
Reged: 01/18/08
Posts: 37
Loc: Poway, CA
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I'm quite happy with mine. I'm in the process of "fine tuning" the collimation, but then again, is it ever going to be perfect? I get good feedback from other people looking through it in star parties. It's my first scope so I really have nothing to compare it to as far as previous scopes. A little more aperture would be nice as I've noticed a dramatic increase in detail with larger scopes, like big scts and dobs, but then you get into portability and other issues so it turns into comparing apples to oranges.
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150 mm Orion Mak Cass
Sky View Pro EQ
Meade 5000 26 mm
Meade qx 20 mm
Meade qx 15 mm
W/O spl 12.5 mm
S/V enhanced diagonal
9x63 Celestron Ultima Binos
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sang33ta
professor emeritus
Reged: 07/08/08
Posts: 524
Loc: UK
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As an alternative you can read my Hioptic 150mm Mak review in my signature, I think they get sold under the brand AstroZap in the USA.
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Hioptic 152mm f12.5 Maksutov
Celestron Advanced CG5-GT Mount (Mr Noisy!)
Meade 4000 Super Plossl Set
Casio QV-2900UX
Got fed up of waiting for Meade ETX-150 so put this together for £500/$1000
Edited by sang33ta (08/08/08 07:50 PM)
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Mert
scholastic sledgehammer
Reged: 08/31/05
Posts: 936
Loc: Spain, Pamplona
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