¶ OpenAstroGuider v3.1 Assembly
If you need the older instructions for OAG v2 or v3.0, go here for v2 or here for v3.0
¶ Required parts
¶ Printed
STL files can be found on Github
- "front"
- "rear" choose the correct focal length and whether or not you'll be using threaded inserts (_TI)
- "cameraMount_v3.1"
- "cameraMount_lid"
- "Lens_holder"
- "Dew_Shield"
- "mid"
The "mid" part is the focuser and can be found in a subfolder. There are several files corresponding to different tolerances. Print the +0.0mm version, then either choose a "+" version if the fit was too tight, or a "-" version if it was too loose. Ideally the print should come out a little bit tight.
¶ Hardware
- 163 or 183mm focal length, 50mm Dia lens
- IMX290 sensor
- OAG v3.1 power board
- Dew Heater (optional)
¶ Screws:
- 4x M4 x 12mm
- 4x M4 T-Nut
- 1x M3 x 12mm
- 1x M3 x 12 Thumbscrew (normal M3 can be used)
- 4x M3 x 4.6 x 6mm Inserts (optional)
- 4x M2.5 x 8mm Standoff screw
- 4x M2.5 Nut
- 4x M2.5 x 12mm
- 4x M3 x 30mm
¶ Preparations
¶ Inserts
If you choose to build OAG v3 with inserts, you will need to use 4 M3x4.6x6 inserts for the rear part. Make sure theyre a little past flush and the surface stays smooth.
¶ Grease
Fully screw on the mid part on the front and rear parts seperately. Move the part around a bit. If the thread is a bit tight at first, this will shave off any excess material to ensure focusing is as smooth as possible later.
https://www.youtube.com/watch?v=67AIe6izyMI
Push both front and rear parts into each other multiple times to ensure the parts aren't binding
If you don't have any grease available, skip this step. Adding some grease is highly recommended though.
Apply a generous amount of general purpose grease to the thread and top section of the rear part. Apply extra grease to the three sprockets.
Also apply grease to the thread part of the front guider part.
Check if the front and rear parts can move into each other with relatively little resistance.
¶ Assembly
¶ 0. Dew Heater
Skip this step if you will not be installing a dew heater.
Stick the dew heater to the lens. It comes with adhesive applied to it.
Use the lens holder to push it on properly.
¶ 1. Front
Insert the cables of the dew heater through the little channel in the front part.
Insert the lens into the front part. The slightly rounded side of the lens should face the front.
Insert the lens holder so that the little cutout lies over the bump of the dew heater. Then screw in the dew shield. Don't screw this in too tightly.
¶ 2. Mid
Screw the mid part to the front. On the mid part there is a tiny arrow printed in, this should face towards the front. The threads start where the arrow and the "T" marking on the front part is, so it'll be easiest if you try catching the thread around that area.
Catch the thread and then rotate it another full rotation until the arrow and "T" are in line.
¶ 3. Rear
Move the Dew heater wires through the opening in the rear part.
Then screw on the rear part to the focuser. Like the front part, the thread starts around where the little "T" is.
Note that the rear part has a lefthand thread, so screwing it in requires lefthand rotation, opposite of a normal thread. Righty loosy, lefty tighty!
Catch the thread and then rotate it another full rotation until the arrow and "T" are in line.
Now hold both rear and front with one hand so that the "T" markings on both parts stay in line and rotate the mid section to the right. This will move front and rear inwards.
Once front and rear meet, the three sprockets on the rear section will engage with the front. Once that has happened you can stop holding front and rear and just rotate the mid further, until it's corners start meeting the "T" shapes. The Guider will now be roughly in focus.
¶ 4. Camera mount
Drill out the material in the holes of the camera mount and lid. You can alternatively use a M3 Key to push it out.
Insert the 4 M2.5 into the camera mount. If they don't go in, you can use a 5mm Key to push them in fully.
Insert the IMX module into the camera mount. The USB plug should face the cutout in the printed part.
Screw in the 4 standoff screws and attach the short 4 pin cable to the IMX. Orientation doesn't matter.
Attach the PCB with 4 M2.5x12 screws. The cutout in the PCB goes over the USB connector of the IMX. Then connect the cable to the port labled "IMX".
¶ 5. Assembly
Attach the 2 Pin JST connector to the Dew heater wires, then insert it through the opening in the camera mount.
Connect it to the PCB. Pull any excess cable into the housing and tuck it to the side.
Insert the power switch into the lid, with the cables facing the longer side.
Connect the JST plug to the PCB. Tweezers might help with this.
If you aren't using the dew heater, cover the opening for the power switch in the cover with the little printed plug
Now is a good time to remove the little protective film on the IMX, if you haven't already.
Insert the cover in the camera mount. Push the 4 M3x30 screws through the holes and screw the assembly to the scope. If you are using the dew heater, make sure the cable coming out of the camera mount lines up with the rear part cable channel.
Don't overtighten these.
¶ 6. Holders
Take the 2 holder_1 and holder_2. On the holder_1, attach M3 nuts into the slots as shown.
Attach M4x12 and TNuts to all four holders.
¶ Vixen Mount
Attach both holder_1 (the ones with the M3 nut) to the end of a 200mm 2020 extrusion.
Lay the Guider into the hodlers. Make sure the sprockets lock into the recessed parts of the rear holders.
Also make sure the gap between cameraMount and scope is covered by the rear holder. This is to prevent any light from leaking in.
Take the other two holders and attach them as shown. Fasten the M4 screws to the extrusion first, then attach the M3x12 and M3 Thumbscew.
The thumbscrew goes on the front side of the scope, you loosen it whenever you want to adjust the focus.
Lastly attach the Vixen_adapter with 2 M4x12 and TNuts. Make sure its roughly in the middle/in the center of gravity.
Depending on your Vixen clamp, you might need to attach it to the other side.
¶ OpenAstroTracker Mount
TBD