OCAL Electronic Collimator PRO User Manual
- June 7, 2024
- OCAL
Table of Contents
OCAL Electronic Collimator PRO
User’s Manual
The information contained in this document is property of Chaoxing Education
Technology Co., Ltd. The information in this document is subject to change
without notice. Please visit our our official website:
http://www.ocalworld.com/en/ for latest version of program.
Version : 1.30
OCAL User’s Manual
Version
Date
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Version Content
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Version Content
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June 20, 2021
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1
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1
Introduction
1.1 What is OCAL?
Thank you for purchasing and using OCAL electronic collimator. OCAL electronic
collimator is an ideal and superior tool for carrying out precise collimation
of Newtonian reflector, Ritchey-Chrétien telescope, and another reflecting
telescope. Collimating your telescope by our OCAL is an easy and comfortable
experience. By idea condition, it’s asy to archive minium 0.08mm primary
mirror axial errior. LOCAL PRO is an upgraded version from OCAL. Not only
change outer shape but also more precisely calibrated of image sensor’s
position. We include M42 to M48, M42 to 1.25 inches adapters with OCAL PRO. By
using OCAL Pro, you can easy to operate it by mobile phone. It’s more
convenient to collimate your telescope without laptop or desktop PCs. Before
using OCAL, we strongly suggest you read this manual at the first place. If
you have any questions about OCAL and the collimation of your telescope,
please contact us via email: huogo558@gmail.com
or WeChat ID: 175768073. We will reply you ASAP.
Product Description
2.1 Product Parameter
ocal side length is 51mm, height 32mm, weight 134 gram. connect PC by a USB
type A male / USB type A male cable, connect to mobile phone through OTG
adapter. support Android and Microsoft Windows 7 and above operating systems.
2.2 What’s in the Box
2.3 Software
Please download the OCAL operation program on the offical website. Both PC
Windows base and
Android Tablet/mobile phone are supported.
2.4 Product Safety Issues
OCAL is certificated by U.S. FCC and EU CE to ensure property safety.
Prepare to Use OCAL
3.1 Install the Collimator
There is M42 x 0.75 female threads on OCAL after open the top cover. We
recommend the following methods to setup initial OCAL
3.1.1 If your focuser has M42 x 0.75 male threads, just screw up OCAL to the
thread on the focuser directly.
3.1.2 If there is no threads at ending of the focuser and it use compressing
ring or screw fixed brass ring. Please use some kind of extension adapter,
such like 2-inch to m42Screwing OCAL to the coupling threads of coma
corrector lens, and insert coma corrector lens into focuser directly. This
method will get a more precise collimation. 3.2 Connect to the computer Just
connects OCAL to the computer through the USB type A cable is attached with
the OCAL product. Plug and play on the Windows operation system.
3.3 Precautions Before Use
3.3.1 Eye Point
We denfine the distance from secondary mirror to OCAL as “EyePoint Distance.”
The OCAL view of A and B have little difference between red and greed circles.
The eyepoint of type A is a shorter distance than type B. We will see a large gap between red and green circles, that means we are easy to distinguish red and green circle. However, OCAL at type B eye point distance, we will get more precise collimation results due to its near-real well-focused position. We recommend you trying type B whlie carry out collimation in order to get best result.
3.3.2 Attached a White Paper
Paste a suitable size of white paper behind the secondary mirror at side wall
of telescope tube. That makes the shape of secondary mirror is easier to
observe.
3.3.3 Center calibration code
Each OCAL has it’s individual center cailbration code. At first, find printed
series number on your OCAL, look up SN and paste the data in that raw and
paste into focus.txt that in the same folder with OCAL program.
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SN is 1d34| Find 1d34, then copy the string of 0 0 165.27 1218.68
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Edit focus.txt| Paste the string of 0 0 165.27 1218.68 into focus.txt and save the file.
3.3.4 Operating OCAL program
Main screen
After execute OCAL.exe, then “Turn on Camera”.
Drag the corner of Camera window, to enlarge the display size.
Click “Camera Settings”. There are some video setting. Adjusting Brightness, Contract or other setting to a suitable value.
Click “Camera Control”. Try to adjust Focus and Exposure to suitable value.
3.3.5 Center offset function
Due to manufacturing and telescope adaptor tolerances, the OCAL program
reticule may not be perfectly in the geometric center, we use center offset
function to do slight adjustment.
The adjustment method is quite simple. Just find a circumference inside coma
corrector or focuser. Then use it as a reference to adjust the offset value.
Check Circle 1 on, it shows a “green” circleAdjust it’s size to match the
inner circumference of coma corrector lens.
Here have gap. Adjust offset value to make green circle to fit the inner circumference of coma corrector lens.
In this example, green circle is perfect matched. And center offset value is Vertical: 2; Horizontal: -3; You may save these parameters by click “Save Config.”
3.3.6 PRO Version Interface Introduction
The interface of the PRO version and the computer version are different, but
the functions have been perfectly reproduced. The following picture is an
introduction to the interface of the PRO version.
1 Exit 2. Basic settings 3. Fine-tuning button 4. Select round button 5.
Length and thickness button 6.
Save config 7. Center offset function 8. Display working area
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Exit button, click to exit the software.
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The basic settings of the computer version, the brightness, contrast, focal length and exposure,parameters can be adjusted by pulling the adjustment lever.
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Adjust any adjustment lever in the software, which can be finely adjusted through the +button. the value of a single click increases or decreases by 1, and a long press can accelerate the speed by 10 times.
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Click on the optional red, green, blue circle and cross star.
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The length and thickness of the selected red, green, blue circle and cross star can be adjusted.
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Stand-alone saving config is to save the parameters. long press is to input the centering
code. for the mobile version, the Center calibration code must be entered in X and Y axis separately. For example, the centering code is 0.01643.82.1432.28, the input value of X axis is 1643.82, Y axis the input value is 1432.28, after the input is completed, click Save to take effect. -
Centering offset function, the function is the same as the PC version.
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The software work area display interface.
Step by Step Collimation
Before we start collimating the telescope, we define the orientation in order to understand more clearly.
The most important collimation step of Newtonian telescope is secondary mirror positioning. Once secondary mirror positioning is done, then you have done the most ifficult steps to carry out.
4.2.1 The first step position of secondary mirror
Figure 1
At begining, this is a no collimation example. Let’s go.
Figure 2
Slight loose the center screw of secondary mirror holder. Rotate the holder
and let the secondary mirror towarding to OCAL.
Figure 3
Check “Enable” to show circle 1 and 2. In the example, they are red and greed
circle. Then adjust the size of both circles to roughly equal secondary and
primary mirror. 
Figure 4
Try to adjust A, B, C screws of secondary mirror holder. Let primary mirror to
roughly in the center of secondary mirror.
Figure 5
Rotate secondary mirror. To make sure the reflection of primary mirror in the
secondary mirror is concentric with “red circle”.
Figure 6
Now, we skip notice primary mirror. Adjust B and C screw of secondary mirror
holder to make the outter shape of secondary mirror fit to “green circle”.
Figure 7
Change the radius of green circle on main program, let the size of green
circle matching secondary mirror. Same as the adjustment of fingure 6, fine
tune secondary mirror older screws.
4.2.2 The position of the secondary mirror and the primary mirror
Figure 8
After the adjustment at figure 7, position of secondary mirror is correct,
however the position of primary mirror become incorrect. All we need to do is
to repeat the djustment
from figure 2 to 5.
Figure 9
After few adjustments, secondary and primary mirrors are concentric. In this
example, there is some gap between bottom side of secondary mirror and green
circle. Try to adjust screw A to change the angle of secondary mirror.
Figure 10
Change the radius of red circle on main program, let the size of red circle
matching primary mirror.
4.2.3 The height of the secondary mirror
Figure 11
After all above adjustments. You may still find there is gap between green
circle and edge of secondary mirror. In this case, loosen 1/4 turn (or less)
of main screw of secondary mirror holder to downward it’s height. And repeat
the adjustment from figure 2 to 5 again. If the gap is at top side of
secondary mirror, all you have to do is tighten the main screw.
4.2.4 Adjustment of the primary mirror
In this step, we are going to deal with the three collimation screws of the
primary mirror support. Before this, we must loosen the three lock screws at
first. This step is a fairly easy compared to the secondary mirror adjustment
that we have just dealt with.
OCAL program have the following assistant indicator to help you to carry out primary mirror collimtion. That are crosshairs and small size blue circle. In the next step, we will explain how to use this function to carry out primary mirror collimation.
Figure 12
Check “Enable” to turn “blue circle” and “purple crosshair” on. Adjust to the
similar size of blue circle to OCAL. Then loosen the three lock screws of the
primary mirror holder. Try to tighten one of collimation screw in order to
find out the direction of movement of OCAL and primary center mark which
reflected on secondary mirror.
Figure 13
Adjust 3 collimation screws to make blue circle fit OCAL outter shape and
center mark on primary mirror is also correct centering. In left result, your
telescope is perfect collimated. Every circles are concentric. However in
some cases, the center mark on the primary mirror is not able to perfect
centering. That becausee some telescope makers made flaw on paste center
mark. We will explain how to do in addendum.
4.2.5 Addendum
A perfect collimated Newtonian telescope by OCAL will find the following
features:
(a) Green circle and secondary mirror are concentric; red circle and primary
mirror are concentric.
(b) Crosshair and spider vanes are overlapped.
(c) Blue circle and OCAL are concentric.
(d) Center mark on primary mirror are overlapped to carema lens of OCAL.
In this example, features (a), (b) are true, but no matter how to adjust, (c)
and (d) are not able to archive. Then maybe the position of center mark of
primary mirror is not correct. Here is a example:
Using a concentric jig to find the center of primary mirror.
True center
A Case of Actual Sharing
References
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