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GoldFocus - High-Precision Ordering

*** Important Notice *** Use this ordering page only for ordering a GoldFocus High-Precision Focusing System which supports high-precision focus but NOT collimation.  If you want to order a GoldFocus Plus Collimation System, then click on one of the following:
GoldFocus Plus Collimation for Cassegrains (SCTs, RCs)
GoldFocus Plus Collimation for Newtonians
GoldFocus Plus Collimation for Refractors

If you already know which GoldFocus Mask size you need to order, click Select Mask to immediately go to the GoldFocus Mask size selections.  Otherwise follow the steps below and scroll all the way to the bottom of the page. Select Mask

Determining the GoldFocus Mask Size GoldFocus

The GoldFocus focusing system for digital imaging is a combination of a specially designed GoldFocus Mask and the GoldFocus Analysis Software.  An image of the GoldFocus Mask is shown at the right.

The GoldFocus Mask comes in 14 standard sizes.  Each size is fully adjustable across a range in order to give a good fit for any telescope within its size range.  Choose the GoldFocus Mask size which is correct for your telescope.

Follow the 3 steps below to select the correct size GoldFocus Mask for your telescope.

  1. Decide Between Outside or Inside Mount for Your Telescope.
  2. Measure the Outside or Inside Diameter of Your Telescope Objective Bezel Ring.
  3. Locate Your Measured Outside or Inside Diameter in the Table and Find the GoldFocus Mask Product Number at the Left of the Table.

Step 1 - Decide Between Outside or Inside Mount for Your Telescope

The GoldFocus Mask has mounting studs which hold the mask in place on the telescope objective bezel ring.  The mounting studs can go either outside or inside your telescope objective bezel ring.  See images below for examples of outside and inside mounting.

The GoldFocus Mask can be mounted directly to the objective bezel ring, a glare shield, or a dew shield.  Choose the outside or inside mounting according to how you will be using the GoldFocus Mask.

Note: The Inside Mount of the GoldFocus Mask requires clearance inside the bezel ring to a minimum depth of 15 mm (0.6 inches) for the mounting studs to project inside the bezel ring.  If your telescope does not have the clearance required for the Inside Mount, then you will need to choose the Outside Mount.  If you have any doubt about the required inside clearance, then choose the Outside Mount.

Before proceeding to the next step, decide between Outside Mount or Inside Mount that is appropriate for your telescope.

Inside Outside

Step 2 - Measure the Outside or Inside Diameter of Your Telescope Objective Bezel Ring

Measure the outside or inside diameter corresponding to which of Outside Mount or Inside Mount you have chosen for your telescope.  Measure the objective bezel ring, glare shield, or dew shield according to how you will be mounting the GoldFocus Mask.  Use a ruler or tape measure to measure the diameter accurate to about 0.1 or 1/8 inches or 2-3 mm.  See the image below for an illustration of how to measure the outside or inside diameter.

Diameter

Step 3 - Locate Your Measured Outside or Inside Diameter in the Table and Find the GoldFocus Mask Product Number at the Left of the Table

Using the appropriate table below for either Inches or Millimeters measurements, locate your measured outside or inside diameter in the range of sizes listed under the corresponding Outside Mount or Inside Mount column.  Read the GoldFocus Mask Product Number at the left side of the row containing your measured diameter.

*** For Example Only - You Must Measure Your Own Telescope ***

Example 1 - Consider an 8" Schmidt-Cassegrain.  Suppose the bezel ring projects out with ample clearance of over 15 mm (0.6 inches) from the front of the bezel ring back to the corrector lens.  This telescope has enough clearance to use the Inside Mount.  Suppose the measured inside diameter of the bezel ring is 9.1 inches.  Look under the Inside Mount Diameter Range column in the table for GoldFocus Mask Sizes - Inches.  The measured inside diameter of 9.1 inches falls in the range 8.1-10.0 inches under the Inside Mount Diameter Range column.  The GoldFocus Mask Product Number on that row is G107 and that is the required size for this example telescope.

*** For Example Only - You Must Measure Your Own Telescope ***

Example 2 - Consider a 102 mm Maksutov-Cassegrain.  Suppose the corrector lens is nearly flush with the front of the bezel ring so that there is little or no clearance from the front of the bezel ring back to the corrector lens.  This telescope cannot use the Inside Mount and must use the Outside Mount.  Suppose the measured outside diameter of the bezel ring is 113 mm.  Look under the Outside Mount Diameter Range column in the table for GoldFocus Mask Sizes - Millimeters.  The measured outside diameter of 113 mm falls in the range 90-118 and also in the range 108-146 under the Outside Mount Diameter Range column.  You have a choice between two sizes and the smaller 90-118 is probably preferred.  The GoldFocus Mask Product Number on that row is G50 and that is the required size for this example telescope.

GoldFocus Mask Custom Sizes

If you have special requirements for a GoldFocus Mask, you may inquire about a Custom GoldFocus Mask by e-mail at: info@goldastro.com

GoldFocus Mask Size Selection

GoldFocus High-Precision Focus Mask

GoldFocus Mask Sizes - Inches

GoldFocus Mask
Product Number
Outside Mount
Diameter Range
(Inches)
Inside Mount
Diameter Range
(Inches)
Add to Cart Price
(US $)
G35 2.5 - 3.2 3.0 - 3.7 Add G35 to Cart $ 74.99
G41 2.9 - 3.9 3.4 - 4.4 Add G41 to Cart $ 77.99
G50 3.5 - 4.6 4.1 - 5.2 Add G50 to Cart $ 81.49
G61 4.3 - 5.7 4.8 - 6.3 Add G61 to Cart $ 86.49
G74 5.2 - 6.7 5.7 - 7.2 Add G74 to Cart $ 92.99
G88 6.1 - 7.8 6.6 - 8.3 Add G88 to Cart $ 99.49
G97 7.0 - 8.6 7.4 - 9.1 Add G97 to Cart $ 103.99
G107 7.6 - 9.5 8.1 - 10.0 Add G107 to Cart $ 110.99
G119 8.4 - 10.6 8.9 - 11.1 Add G119 to Cart $ 117.49
G127 9.3 - 11.3 9.8 - 11.9 Add G127 to Cart $ 121.49
G137 9.9 - 12.4 10.4 - 12.8 Add G137 to Cart $ 126.49
G147 10.8 - 13.3 11.3 - 13.9 Add G147 to Cart $ 131.49
G167 11.7 - 15.4 12.1 - 15.9 Add G167 to Cart $ 144.49
G187 13.6 - 17.4 14.1 - 17.8 Add G187 to Cart $ 155.49

 

GoldFocus High-Precision Focus Mask

GoldFocus Mask Sizes - Millimeters

GoldFocus Mask
Product Number
Outside Mount
Diameter Range
(Millimeters)
Inside Mount
Diameter Range
(Millimeters)
Add to Cart Price
(US $)
G35 64 - 82 76 - 94 Add G35 to Cart $ 74.99
G41 74 - 98 86 - 111 Add G41 to Cart $ 77.99
G50 90 - 118 103 - 131 Add G50 to Cart $ 81.49
G61 108 - 146 121 - 159 Add G61 to Cart $ 86.49
G74 133 - 171 146 - 184 Add G74 to Cart $ 92.99
G88 156 - 197 168 - 210 Add G88 to Cart $ 99.49
G97 177 - 219 189 - 231 Add G97 to Cart $ 103.99
G107 194 - 242 207 - 255 Add G107 to Cart $ 110.99
G119 214 - 269 226 - 282 Add G119 to Cart $ 117.49
G127 237 - 288 250 - 301 Add G127 to Cart $ 121.49
G137 252 - 314 265 - 326 Add G137 to Cart $ 126.49
G147 274 - 339 286 - 352 Add G147 to Cart $ 131.49
G167 296 - 390 308 - 403 Add G167 to Cart $ 144.49
G187 346 - 441 359 - 453 Add G187 to Cart $ 155.49

 

GoldFocus Analysis Software

The GoldFocus Analysis Software is included with each purchase of a GoldFocus Mask and is not available for separate purchase.