GSO Crayford Focuser for Reflectors - Dual Speed (Low Profile)

4.0 Nicely Made Product

Compact,Accurate,Strong Construction

This is a well made focuser. It was easy to install, having exactly the same size base as the stock rack and pinion focuser on my G-8N Bird Jones reflector. I would have given it 5 stars if the mounting holes had been drilled at right angles to the tube instead if parallel to the eyepiece axis.

I just filed the holes in the tube to oval them a bit and it mounted perfectly. Now my DSLR comes to fine focus, but I need an extension tube to focus my eyepieces.

The fine focus is superb. I read somewhere these might be a trifle "rough", but not mine. I recommend this focuser highly.

This review was provided courtesy of AgenaAstro.com

5.0 Very nice focuser!

Strong Construction,Smooth,Accurate

None

Great low profile focuser for DSLR imaging. For visual use may require extension tube to reach focus. Overall very smooth and nice. Very satisfied with this purchase!

This review was provided courtesy of AgenaAstro.com

5.0 Good focuser - would buy again.

Strong Construction

A very good focuser, especially at the price. I replaced an older 1-1/4 inch JMI NGF on my home made 12 inch truss Dob with this 2 inch low profile focuser (with 1-1/4 adapter). Aside from it being slightly heavier and requiring a little scope rebalancing and having about 1/2 inch less in-focus than the older focuser which required cutting 1/2 inch off my truss tubes, it is a very good fit. I took advantage of the instructions to lube the 10:1 speed reducer before installing it, and it is very smooth. Probably not a Feathertouch but it's very good and, hey, it's 1/3 the price!

This review was provided courtesy of AgenaAstro.com

5.0 Nice Focuser, simple and Quality

Accurate,Strong Construction

Heavy

A nice simple focuser, I used on a 200mm/8" scope I built. The 10 to 1 reduction works great, and the 1.25" adapter is great to have for smaller lenses. The friction adjustment works well, just remember to use a slightly tighter setting for those big 2" inch eyepieces. Simple construction and solid material, is not only a great value but very durable and as functional as can be for this type focuser.

This review was provided courtesy of AgenaAstro.com

5.0 Great price/quality ratio!

easy to focus,Smooth

That's all you need to find perfect view in your eyepiece. You don't have to waste your time finding out if it's focused or not.

This review was provided courtesy of AgenaAstro.com

4.0 Good, but be beware of few issues

Compact

Good focuser for visual use. For astrophotography it has one issue that complicates things. The problem is that due to its small size and internal lay-out the focuser tends to sag when tightened. The focusing tube becomes tilted a bit which deteriorate collimation, etc. Still can be used succesfully as it gives less vignetting than the full profile one on fast newts.

This review was provided courtesy of AgenaAstro.com

4.0 An affordable upgrade for chinese r&p fo

Strong Construction

I upgraded to this crayford focuser on my 10inch GSO dob, and it is definitely a worthwhile upgrade. While the focusing isn't as smooth as some of the truly premium focusers, it is a magnitude better than the stock R&P focuser my scope came with. The fine focus knob is absolutely adequate for reaching precise focus at high magnifications.

The real benefit of this focuser is that there is zero image shift or play in the focuser barring an extremely heavy eyepiece. This has allowed me for the very first time dial in perfect collimation and get the most out of my optics.

Finally, I am very glad I got the low profile version of this focuser because some of my eyepieces definitely would not have come to focus with the normal one. You can always lengthen your optical path, but it is very difficult to get more in-focus than the minimum your focuser allows.

This review was provided courtesy of AgenaAstro.com

4.0 Smooth and well-constructed focuser

Compact,Strong Construction

Got this for a 13" kriege-style dob I built. Excellent quality and machining...can't image using any focuser now without the dual-speed option. Have gotten this same brand for my refractors...consistent quality always. A pleasure to use.

This review was provided courtesy of AgenaAstro.com

4.0 GSO Crayford Focuser for Reflectors

Zero image shift,Low cost,Low profile for imaging

I purchased the GSO Low Profile Crayford focuser as an upgrade for a Celestron C8-NGT Newtonian Rack and Pinion focuser. The focuser fit the Celestron optical tube without mounting hole modifications. Slightly longer metric screws are required, but this is a minor problem as they are available at local hardware stores. I did have some concern about the mounting hole pattern before purchasing. The information about the focuser indicates that the holes are 70mm along the telescope tube, and 73mm perpendicular to the tube. The 70mm is just as stated, 70mm center to center parallel to the optical tube measured along the body of the tube. The 73mm is more obscure in my opinion. This measurement is from hole to hole straight across on the inside of the optical tube, not along the surface of the tube. This measurement is best done with a flexible tape measure. In the end, there were no mounting hole issues and the focuser fit exactly on the optical tube without problems. The curvature of the mounting plate fit the 8" Newtonian as well.

The weight of the focuser (on my scale) was about 1 lb. 4.5 oz. with the 1.25" adapter installed. This is just a slight increase over the Rack and Pinion being replaced at 1 lb. 3 oz.

I saw conflicting reports about lifting weight of this focuser. Here are my results:

Greater than 7 lbs. - too hard to tighten tension screw
7 lbs. - lifted, but too stiff
6 lbs. - coarse stiff, fine adjust ok
5 lbs. - coarse a little stiff, fine adjust ok
4 lbs. - coarse ok, fine adjust ok

There are two 2mm allen set screws (uses 2mm allen wrench) on the base that have to be removed to attach the mounting plate to the optical tube. This is due to one of the mounting screws being blocked otherwise. These allen screws allow the focuser to rotate to any angle with respect to the optical axis. This is a good feature for Newtonians allowing the focusing knobs to be set at various angles.

Replacing the Rack and Pinion with the Crayford focuser allowed collimation of this telescope for the first time. The Rack and Pinion focuser had so much image shift during focusing that collimation was not possible. This focuser has zero image shift when focusing with an eyepiece. There is, however, image shift when the focus lock screw is engaged. [The focuser includes one thumb screw for focus tension, and one for focus lock.]

The low profile design allows imaging configurations that require more distance between the scope and the film plane, such as the use of filter wheels, etc.. In order to use eyepieces, I add the GSO 50mm extension tube. All of my eyepieces focus well with this configuration.

This review was provided courtesy of AgenaAstro.com

4.0 Quite nice

Smooth fine focus, Compression Rings, Fit and Finish

Coarse focus just a little stiff.

I have just installed a new GSO (Guan Sheng Optical) dual speed low profile crayford focuser with a 10:1 ratio on my 12.5" Dicovery PDHQ Dob. The focuser really has a nice feel and finish, better than I had expected. The focuser and the 1.25" adapter both utilize compression rings which will save my eyepieces from set screw marks on the barrels. I ordered it through Agena Astro and it arrived in 2 days.

Installation was a snap, I only had to drill 2 mounting holes in the telescope tube and that's it. I bolted it on and re-collimated my scope. My heaviest eyepiece setup is 4 lbs. and this focuser lifts it with no problems at all which seems to be the concern of some folks but that sure seems unfounded by me. With the micro focus I have been able to squeeze out the finest details from Jupiter and other objects.

4.0 Nice Focuser

Accurate,Strong Construction,Smooth fine focus,Easy installation,Compression rings

I have just installed a new GSO (Guan Sheng Optical) dual speed low profile crayford focuser with a 10:1 ratio on my 12.5" Dicovery PDHQ Dob. The focuser really has a nice feel and finish, better than I had expected. The focuser and the 1.25" adapter both utilize compression rings which will save my eyepieces from set screw marks on the barrels. Installation was a snap, I only had to drill 2 mounting holes in the telescope tube and that's it. I bolted it on and re-collimated my scope. My heaviest eyepiece setup is 4 lbs. and this focuser lifts it with no problems at all which seems to be the concern of some folks but that sure seems unfounded by me. With the micro focus I have been able to squeeze out the finest details from Jupiter and other objects.

This review was provided courtesy of AgenaAstro.com

4.0 GSO Crayford Focuser for Reflectors - Dual Speed Low Profile, 10:1 Mic

Zero image shift for eyepiece use. Low profile for imaging applications. Low cost.

Image shift when focus lock screw engaged.

I purchased the GSO Low Profile Crayford focuser as an upgrade for a Celestron C8-NGT Newtonian Rack and Pinion focuser. The focuser fit the Celestron optical tube without mounting hole modifications. Slightly longer metric screws are required, but this is a minor problem as they are available at local hardware stores. I did have some concern about the mounting hole pattern before purchasing. The information about the focuser indicates that the holes are 70mm along the telescope tube, and 73mm perpendicular to the tube. The 70mm is just as stated, 70mm center to center parallel to the optical tube measured along the body of the tube. The 73mm is more obscure in my opinion. This measurement is from hole to hole straight across on the inside of the optical tube, not along the surface of the tube. This measurement is best done with a flexible tape measure. In the end, there were no mounting hole issues and the focuser fit exactly on the optical tube without problems. The curvature of the mounting plate fit the 8" Newtonian as well.

The weight of the focuser (on my scale) was about 1 lb. 4.5 oz. with the 1.25" adapter installed. This is just a slight increase over the Rack and Pinion being replaced at 1 lb. 3 oz..

I saw conflicting reports about lifting weight of this focuser. Here are my results:

Greater than 7 lbs. - too hard to tighten tension screw
7 lbs. - lifted, but too stiff
6 lbs. - coarse stiff, fine adjust ok
5 lbs. - coarse a little stiff, fine adjust ok
4 lbs. - coarse ok, fine adjust ok

There are two 2mm allen set screws (uses 2mm allen wrench) on the base that have to be removed to attach the mounting plate to the optical tube. This is due to one of the mounting screws being blocked otherwise. These allen screws allow the focuser to rotate to any angle with respect to the optical axis. This is a good feature for Newtonians allowing the focusing knobs to be set at various angles.

Replacing the Rack and Pinion with the Crayford focuser allowed collimation of this telescope for the first time. The Rack and Pinion focuser had so much image shift during focusing that collimation was not possible. This focuser has zero image shift when focusing with an eyepiece. There is, however, image shift when the focus lock screw is engaged. [The focuser includes one thumb screw for focus tension, and one for focus lock.]

The low profile design allows imaging configurations that require more distance between the scope and the film plane, such as the use of filter wheels, etc.. In order to use eyepieces, I add the GSO 50mm extension tube. All of my eyepieces focus well with this configuration.