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HoTech 1.25" SCA Laser Collimator - Single Dot
| Brand | HoTech |
| Part Number | SCA-1.25D |
| Availability | available |
| Share |
Product Info
Manufacturer Description
Voted "Hot Product - 2009" by Sky & Telescope
"There is a tremendous amount of creativity and cleverness being displayed, all backed by a fervent devotion to making the sky more accessible and enjoyable for astronomy enthusiasts at all levels. It is truly inspiring." - Robert Naeye, Sky & Telescope Editor in Chief
- Ideal for collimating Newtonian reflector telescopes. May also be used to collimate SCTs (additional steps required; see detailed product manuals/videos below before ordering).
- Uses innovative Self-Centering Adapter technology for most precise centering and collimation
- Made of aero-space grade lightweight aluminum material and CNC machined
- 45-deg faceplate with targeting grid allows more convenient alignment from the rear of the telescope
- Over 65 hours of operation with included CR123 batteries
- Available in 1.25" and 2" models
Laser Collimator with Self-Centering Adapter (SCA) - Provides Repeatable Installation
The HoTech laser collimator separates itself from all other laser collimators with its innovative self-centering adapter technology (SCA). This mechanism allows precise and repeatable installation in all brands of 1.25" and 2" telescope focusers, thus providing accurate collimation. All laser collimators in the current market have one fundamental problem, slop in the adapting mechanism between the laser collimator and the telescope focuser. This problem is clearly recognized and often discussed among astronomers but so far there has been no definite solution in the market.
No matter how tightly the tolerances machined on the laser collimator or the focuser, a small gap is required to allow installation of the laser collimator. Once the laser collimator is inserted, the required gap becomes a problem. A laser collimator is secured with one or more thumbscrews or unified compression ring. Both methods introduce a very critical issue, namely an off-axis installment that instantly destroys the precision of your collimation instrument along the entire optical axis.
HoTech's Self-Centering Adapter cleverly eliminates the slop by linearly compressing the built-in rubber rings.
By doing this, the diameter of the rings expands to compensate the gap. Because all rings evenly expand radially in diameter from the compression, this automatically centers the laser collimator in the focuser draw tube. And most importantly, the SCA laser collimator can be tightly installed in the focuser for a repeatable installation to provide accurate collimation.
In summary, HoTech's SCA adapter serves three critical functions.
First, its expansion rings accommodate almost all focuser's manufacturing tolerances. Second, it automatically centers the adapting laser. Third, it provides at least two evenly distributed circular contacts on the focuser's inner tube surface preventing the adapting laser from pivoting. Once the slop factor is taken away, you can quickly collimate your telescope in confidence to achieve perfect collimation every time.
Problem Solved with SCA Adapter Technology
1. SCA Eliminates Drawtube Slop
All drawtubes have manufacturing tolerances. They require a larger diameter to accept various eyepieces and adapters. When a standard collimator is inserted, the gap between the drawtube and the inserting device becomes a slop problem. The rubber rings in the SCA expand radially according to users own adjustment to fill the gaps. This makes your collimator seat firmly in your drawtube, becoming part of your telescope for a secure and repeatable installation.
2. SCA Eliminates unstable locking from thumbscrew or unified compression ring
The optical axis is shifted when the inserting device is locked in by thumbscrew. In some cases, some poorly made unified compression ring can cause unstable tilt when locking in the drawtube due to loose tolerances between the compression ring, inner groove, and the uneven tip of the locking thumbscrew in a drawtube. The SCA adapts the collimator itself without using the thumbscrew or the unified compression ring.
3. SCA Accepts the Imperfection of a Drawtube
Despite small imperfections inside the drawtube like dents, scratches, and uneven burrs, the rubber rings compensate the errors and faithfully center the collimator in the tube. In addition, even if the drawtube is slightly deformed in diameter (egg-shaped), the rubber rings in the SCA will compensate for the differences and faithfully center the collimator. A metal collet design will not be able to transform itself to the deformed shape to compensate the imperfection of a drawtube for a sturdy adaption.
More SCA Laser Collimator Features:
Laser Engraved 45-deg Targeting Faceplate
The targeting faceplate displays the returning laser spot with a clear visual reference during adjustment. That allows you to align your primary mirror from the rear of the telescope eliminating traveling to the front of your scope repeatedly during collimation.
When collimating without the targeting faceplate, you will not be able to adjust the primary mirror in real time referencing the laser dot. In other words, you often get lost on which adjustment screws you used due to traveling back and forth for referencing the direction you have adjusted. This results in considerable time to complete the collimation and defeats the purpose of quick and easy laser collimation. HoTech understands the importance of this, so the faceplate is a standard feature in their laser collimators. All astronomers deserve to have it without paying anything extra!
In addition, the faceplate viewers pattern is laser engraved to ensure a long lasting sharp targeting grid for best visual effects. Unlike other collimators, the target is not a sticker that will peel, or paint that can rub off or chip. HoTech understands that you are paying for a precision instrument that is supposed to be well made.
Finest Projecting Laser Dot
Keeping the laser dot to the finest point is the key to precision collimation. But when you look closely at the laser dot from brand to brand, most laser dots appear large; not really a fine point as you might have imagined. This means that there is guess work involved when you try to center the dot; not just centering the laser dot to the center of the faceplate, but also centering the center of the dot itself. This does not make any sense when you are trying to take the advantage of the collimated laser beam's characteristic which has a low beam divergence, so that the beam radius does not undergo significant changes within moderate propagation distances. In other words, the laser beam size within the collimation distance (laser collimator to the primary mirror and back to the faceplate) should remain a constant fine point. As you know, most laser collimator brands are not really laser manufacturers. They install an off-the-shelf laser module or pointer and align the laser in a tube without REALLY considering the user’s application, namely the operating distance for a laser beam size. HoTech has been designing and building laser modules and systems for over 10 years for various professional industries. We know exactly how a laser should work. We limit our laser beam to the finest size in the correct operating distance for optimal effect. Our understanding and experiences with the laser design permit you to have an effective and precision collimation.
High Accuracy Laser Alignment
The HoTech laser collimator is well centered and aligned which are critical factors for an accurate collimation. But you will be surprised that many laser collimators in the market fail in this regard. The reason is in the design and understanding of the product itself.
HoTech has considered all aspect of parameters in their design. Parameters like the alignment mechanism, mechanical and optical structure of the laser itself, and more are taken as part of the laser collimator's design. For instance, some laser collimators actually install an off-the-shelf laser pointer in the casing. It is very cost effective (for the seller), but it inherits numerous problems. In many cases, the laser pointer might not install perfectly centered in the casing due to pointer size variations and the added alignment mechanism. So the laser itself is not positioned on the true alignment point and optical axis. As the result, the laser can never be center-aligned in the enclosure. It is possible to align the laser beam parallel to the optical path but always with an offset along the optical axis. This means the laser beam is off no matter how you center adapt the laser collimator to the focuser. The result of off-centered laser will introduce astigmatism into your telescope.
Light Weight Design and All Aluminum Body Machined with High Precision CNC
Many laser collimator manufacturers give users the wrong impression, big and heavy means rugged and stable. Instead, HoTech engineers successfully cut the unnecessary weight on the laser collimator because they understand that additional weight on a telescope (especially open structure Newtonians) will create imbalance and structure sagging. In addition, the heavier the device is, the more inertia it will have during an impact from an accidental drop. In such an accident, the inertia force can cause more damage to the internal alignment mechanism because there is more energy required to dissipate from the impact. Therefore, the lightweight design on this laser collimator makes you gain reliable precision collimation. And, of course, Hotech laser collimators use aerospace grade lightweight aluminum material and are CNC machined with the tightest tolerances, then sand blasted and anodized to protect them from harsh environments. Nothing has been sacrificed while you get a long lasting state-of-the-art collimation instrument.
Long Lasting Battery Life
By using a CR123, 3V battery as the laser power source, HoTehc's laser collimator has over 65 hours of continuous use battery life time. The included CR123, 3V lithium battery operates well under a typical cold night and it has a 10-year shelf life. This is a great advantage since you don't have to worry about changing the tiny, hard to find cell batteries frequently in the dark like other collimators.
Collimation for your SCT
Commercially made SCTs all have slight optical and mechanical alignment errors. The error typically is in the centering of the secondary mirror. As a result, when a laser is installed and emitted from the focuser, the beam will seldom return dead center, even though star testing would indicate perfect collimation! In addition, the secondary mirror (convex shape) magnifies any error by about 5 times. The error of deviation for a typical well-collimated SCT will return laser beam at around 0.125" to 0.25" off center. In order to compensate the optical and mechanical alignment errors of SCT, a different collimation approach is required in comparison with Newtonian telescopes. If the procedure is followed through correctly, users can still accurately collimate their SCT.
By default, the laser will have to be positioned in the optical center of the SCT. The HoTech SCA laser collimator automatically eliminates the focuser slop without using the thumbscrew and center-positions itself on the optical axis. For SCTs, the primary mirror is fixed, but you can collimate by adjusting the secondary mirror to a point parallel to the optical axis.
There is an one-time-only preparation that you need to do for SCT laser collimation using this collimator. First, install the SCA laser collimator and premark the laser position on the target grid of the collimator when your telescope is collimated from the factory or from your star collimation. Then when you check for collimation next time, just adapt the SCA laser collimator on the focuser, 2" or 1.25", and see if the laser falls on the premarked laser position. If not, adjust the alignment screws on the secondary mirror to move the returning laser dot to the premarked postion on the target grid. See illustrations below.
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Diffraction Grating Pattern Lens on the SCA Laser Collimator
Since HoTech's SCA Laser Collimator is already accurate with the SCA technology, fine laser dot, and the built-in 45 degree faceplate, there is no need to use the DFG pattern to align the primary mirror of a Newtonian telescope. The purpose of using the DFG pattern is to eliminate gross misalignment the primary mirror. The user aligns the primary mirror by referencing the shadow of the secondary in the projected DFG pattern on a wall, and the user counts the DFG dots around the shadow to center in the shadow. This method cannot achieve accurate alignment because the gap between each dot can make a big alignment difference. At the final alignment stage, the user must bring the laser dot back to the laser exit (the center of the 45 degree faceplate). HoTech's built-in 45 degree faceplate allows you to align your primary mirror from the rear of the telescope eliminating traveling to the front of your scope repeatedly during collimation like other collimators. Therefore, there is no need to use DFG lens in conjunction with HoTech's SCA Laser Collimator.
Reviews
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Jan 14, 2019
Great product
Pros: Cons: Comments:I bought this HoTech laser collimator to use on my XT8. Easy to follow instructions and spot on collimation. What more could you ask for. Highly recommended.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Oct 15, 2018HoTech 2" & 1.25" SCA Laser Collimator
Pros: Cons: Comments:Easy to use - instruction are pretty clear. Agena Astro Products was great in getting it to me in 3 days (regular postage). Looks like I have a main source for my astronomy needs!
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jul 16, 2018Good product overall
Pros: Cons: Comments:I have a couple of entry-level Newtonians (80mm & 130mm) & I used this to collimate them since that operation had never been done previously. Unit worked as advertised after I had marked the centers of the main mirrors (neither of these cheaper units had markings from the factory). My only suggestions would be to have a smaller laser spot & to include some center mark stickers for mirrors in case they are not factory marked. I used tiny O-rings like the ones in eyeglass repair kits & glued them onto the mirror centers which worked reasonably well. Checking the laser-collimated scopes on a star, the out-of focus ring patterns were concentric as per the provided instruction sheet.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Apr 7, 2018a good solution
Pros: Cons: Comments:I've tried cheaper laser collimation devices and they are worth what you pay for them. These center in the focuser and give repeatable results regardless of specific orientation.
Bottom Line: Would you recommend this item? Yes
I think the cross hair version might be more helpful, but then again, this is my outreach dob, not some photographic system.This review was provided courtesy of AgenaAstro.com
Oct 15, 2017Excellent accessory
Pros: Cons: Comments:My 11 years old son can collimate both mirrors of our SW 130PDS for 15 minutes. And yet had time to eat 2 apples during this procedure;-)
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jul 18, 2017Great
Pros: Cons: Comments:It was able to colimate my F 4.4 20 dob no problem at all. I wouldve liked an on of switch on it but the system on its own is worth a billion stars. This thing is rock solid.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Apr 22, 2017Works like it should
Pros: Cons: Comments:I bought this for an 8 in reflector. It fits good and snug in the focuser and my collimations has never been better.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Feb 17, 2017No more running back and forth
Pros: Cons: Comments:Great when using on any scope when it it longer than the space between your eye and your hand. As long as you can see the red dot and know when it centers on the palate, collimating becomes a little easier. Make it a one man job.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Oct 26, 2016The right tool for the job and well worth the money
Pros:Accurate,Easy to Use,Self Centering Mount
Cons: Comments:This is the second laser collimator I have purchased and hopefully will be the last. This was purchased to replace one of the cheaper units because that laser was not accurate. I am really happy I bought this unit. I was able to successfully align my primary and secondary mirror with no problems at all. I always check/perform an alignment at night after the scope is cooled for the best results . The best views I have seen since I have owned this scope are after getting this collimator. My scope is an Dobsonian 8" Orion f/5.9. I would assume this would work well on faster scopes. The best part is the self centering feature which helps to ensure the tool gets mounted the same every time. I found that after getting the orings tightened down in the focuser, rotating the whole assembly while pressing towards the focuser ensures it is perfectly centered and seated every time.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Feb 4, 2016Precision Instrument
Pros:Strong Construction,Accurate
Cons: Comments:I wanted a quality collimation tool that would be easy to use. The unit fits snugly in my 2" focuser and the laser dot is easy to see. I am able to collimate my 12 1/2" dob in 5 minutes. Build quality is solid.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Feb 21, 2015Quick, accurate collimation
Pros:Accurate,Easy to Use,Fast
Cons: Comments:I wanted an accurate, easy to use laser collimator that fit snugly and securely into my 2" focuser. The twist to enlarge design uniformly expands within the focuser until it is very snug. The laser is sharp and not too large, which is an added plus. I was able to complete collimation in about 2 minutes. Highly recommended.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 30, 2014Gets the job done
Pros:Easy to Use,Accurate,Strong Construction,Case Included,Lightweight,Compact
Cons: Comments:The self-centering compression ring is the best feature of this unit. No on/off button is provided, instead, the battery cover needs to be unscrewed slightly to turn off unit, other than that, this collimator is one of the best in the market right now and the price can't be beat. Highly recommended!
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 25, 2014If you have a 2" focuser you need this!
Pros:Strong Construction,Accurate,Compact,Easy to Use,Lightweight
Cons: Comments:I have three Newtonian astrographs. Two of them are custom built and one is an AT6IN. The Hotech 2" laser collimator made easy work out of what can be a difficult or annoying task. I did lots of research before I bought this one and I am glad. This Hotech collimator is staying in my case that I bring out every imaging session.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jan 25, 2014Great tool
Pros:Easy to Use,Strong Construction,Accurate
Cons:None
Comments:Shipping Great, and the best thing is that with this collimator all the time spent doing this before, is now reduced to literally 5min max.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Sep 27, 2013Excellent Product!!!!!! - Honest Seller
Pros:Quality Lenses,Compact,Strong Construction,Lightweight,Accurate,Easy to Use
Cons: Comments:Excellent product. Accurate and very easy to use. This makes collimation easy and pleasant process like a game.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Feb 9, 2013Decent Laser Collimator
Pros:Strong Construction,Compact,Easy to Use,Lightweight
Cons: Comments:I bought this laser collimator because it looked to be a step above the standard laser collimators, but a lot cheaper than the top of the line lasers.
Bottom Line: Would you recommend this item? Yes
The collimator comes in a very nice storage case and has a very solid construction.
I use the collimator for collimating my Orion XT10i dobsonian telescope. The compression ring system supposedly compensates for any focuser slop, but I still get slightly different results if I reinsert the collimator after a collimation session.This review was provided courtesy of AgenaAstro.com
Feb 8, 2013Decent collimator
Pros:Easy to Use
Cons: Comments:Be sure to check the collimator's collimation! Mine was way off. Company claims that it is extremely rare to get one that is out of collimation, but would check mine an replace if I was right. I WAS right and they replaced at no cost to me. There are better collimators out there, but at a much higher price. Overall, a decent product.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Sep 24, 2012Steady, repeatable collimation
Pros: Cons: Comments:After reading many reviews of laser collimators I questioned whether laser collimators were worth trying at all. Most of the complaints that were that they fit loosely in a 1.25" adapter, alignment seemed to change everytime people tried to align their optics, and visual collimation did not match laser collimation.
Bottom Line: Would you recommend this item? Yes
I choose the Hotech laser collimator specifically with this problem in mind. The Hotech collimator does not rely upon the set screws in your EP adapter, which can push the collimator off center or off axis, and vary depending on which way the EP adapter is turned. Indeed, the instructions specifically tell you not to tighten the set screws.
A recurring complaint that I read from many users is that after doing a laser collimation, optical collimation was way off. I visually checked collimation on my scope and everything was aligned and centered better than I had ever achieved before, and with far less time and frustration.
Another thing that I like about the Hotech laser collimator is that it uses lithium CR123 batteries. These are not terribly common for most products, but have a projected 10-year shelf life. I've been very please with the power capacity and durability of the CR123 batteries in other services so it seemed like a good choice for the collimator.
The Hotech collimator did an excellent job of collimating my telescope, with no problems with repeatability, and no problems with visual confirmation. The only thing I probably would have done differently is to get the 2" rather than the 1-1/4" version, as it requires an adapter to fit my 2" focuser.This review was provided courtesy of AgenaAstro.com
Ouranos New Member
- Skill Level
- Unknown
- Time with Product
- Unknown
- User Notes:
- Review by Gator of Near Chicago.
Oct 29, 2011Great Tool
Pros:Easy to Use,Strong Construction
Cons: Comments:I use the Hotech collimator on my Orion XT10 Dob. It is a great tool to aid in collimation both at home and in the field. I highly recommend it.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 2, 2011Great Collimator!
Pros:Strong Construction,Compact,Accurate
Cons: Comments:I purchased this after seeing the Hotech videos on Youtube.
Bottom Line: Would you recommend this item? Yes
It looked easy to use and their videos made the process completely understandable.
When I received the collimator I was pleasantly surprised to find the precise construction and it really seemed like a professionally engineered product.
On first use I felt the collimator totally paid for itself, it was so simple and easy to get my telescope aligned I am only surprised I didn't buy this sooner.This review was provided courtesy of AgenaAstro.com
May 19, 2010Finally a laser collimator that works!
Pros:Strong Construction,Accurate
Cons: Comments:After 3 other units I tried were a little sloppy in the focuser and not very accurate I decided to try this one and am sure glad I did. It is as advertised. No faults with this one, I would buy another one.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 26, 2009HoTech SCA Laser Collimator
Pros:Accurate,Compact,Light weight
Cons:None
Comments:It's about time, a laser collimator that doesn't move around in the focuser because of a sloppy fit
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 26, 2009A very good tool if you have a SCT
Pros:Compact,Strong Construction,Accurate
Cons: Comments:After you collimate your SCT, this is a very useful tool. Set the laser like the directions tell you, and the next time you have to collimate your scope, just line up the laser with the mark you made, and you are set to go.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 26, 2009A very nice collimator
Pros:Easy to use,Accurate,Compact
Cons: Comments:I am quite happy with this collimator. The centering of the laser was quite good upon delivery, yet it can not be adjusted in case it gets misalligned. The SCA technology for centering the collimator in the focuer is a blessing. Works easy and adds a nice deal of accuracy over other laser collimator types. Yet I would preffer a 2" only version as I do not have or intend to have any 1.25" focusers. Would lower the price and increase precision imho. The laser itself is red and brigt enough to preform collimation in dim light/sunset and fine for night use also. The projected dot is small enough after traveling the distance in my 1000mm Newton. The reflective 45degree target face lets you make adjustments on your primary mirror while retaining direct view of their impact. Its engraving futher increases precision imho. Additionally I like the pretty and protective box and good finishing. Even though there are items for further improvement I give 5 stars.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
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