Work in progress!
¶ Introduction
The OpenAstroExplorer shares many of the same usage principles as the OpenAstroTracker, so users familiar with OAT will recognize a lot of the workflow. For general astrophotography knowledge that goes beyond this device, readers can consult the broader Astrophotography and Astrophoto Setup resources. This guide is intended to serve a wide audience – from DIY builders and astrophotography beginners to more advanced users – and aims to provide a clear foundation for everyone.
¶ Quick Start: Your First Night with OAE
For a very brief field manual, please see the dedicated Quick Start Guide. That quick overview assumes that you have already read and understood the broader instructions in this Usage Guide, and is meant as a condensed reference for use in the field.
¶ Before You Start
¶ Choosing a lens and camera
Most DSLRs made in the last 15 years will work fine with OAE. Using your existing gear is the best way to start. Even kit lenses are sufficient for beginners, although a very poor lens can limit results more than an older camera. For those looking to upgrade, many used vintage lenses are excellent, affordable options.
If you want to delve into proper telescopes, detailed information about those would take too much space here. As the OAE functions no differently than other commercial telescope mounts, much of the knowledge and resources available online for astrophotography telescopes will apply here as well. A general rule of thumb: bigger is not always better. Larger telescopes can be heavy, harder to balance, and more demanding on tracking accuracy. Smaller, lighter telescopes often provide a more forgiving and enjoyable starting point, especially when paired with OAE.
¶ Laptop requirements
The OAE requires a computer connection to operate. While OAT can be partially standalone, OAE can not. A Windows laptop is recommended for best compatibility. Linux and macOS can also be used, but with extremely limited support, and some features (such as AutoPA) do not work. The PC handles control software, guiding, and data capture, making it an essential part of the setup.
¶ Why use Autoguiding?
Autoguiding uses a small, dedicated guide scope and camera to monitor a single star during long exposures. If the star drifts, the PC sends corrections to the mount’s motors, dramatically improving tracking accuracy. This allows for longer exposures and higher focal lengths without star trailing. For more details and setup instructions, see the OpenAstroGuider and Guiding pages.
¶ Initial Calibration
(Performed before first use, not required every session)
In order to do these calibrations, you should have the Firmware flashed and set up a connection with a PC with OATControl open and connected.
¶ Home Positions
The following postions are referred to as the home positions for each axis. At the beginning of a session, the mount should be moved into these positions.
¶ RA
¶ DEC
¶ ALT
¶ AZ
The AZ axis is the only axis that does not have a precise indicator. It doesn't have to be moved to a precise point, just having the ground palte somewhat straight is enough.
¶ RA & DEC Axes
If these terms are unclear to you, check the corresponding section in Astrophotography.
-
Verifying correct steps/degree:
In OATControl, slew the mount exactly 6 hours in RA. This should result in a 90° rotation of the RA axis. If not, double check your step configuration in the firmware. -
Verifying direction:
Home the mount, and set the home position again.
(Increase RA, CCW rotation)
(Decrease DEC, CW rotation)
¶ ALT & AZ Adjustments
The Altitude and Azimuth axis can be moved manually within the mini-ctrl in OATcontrol (Bottom right corner). The 1-5 numbers change the length of the move for ALT/AZ, unlike RA/DEC where it changes the speed.
The control for the ALT and AZ axis on the mount are from the telescopes perspective. So pressing the UP button in OATcontrol might cause the rear of the mount to come down, but that would cause the telescope to look further up. The same thing applies to AZ, when pressing the RIGHT button, the mount will rotate clockwise and the telescope will look further to the right.
The ALT and AZ axis also have a homing feature. When both axis are homed, you can "set az/alt home" in the OATcontrol settings. You can then move the axis back to those locations by pressing "move az/alt to home". The locations are stored between sessions, so even if you power down the mount while ALT/AZ are not in the home position, it will still be able to find home. This only works properly if neither of the steppers have lost steps.
There is currently a bug in the firmware where pressing "move az/alt to home" while the steppers are already at the home position causes the steppers to not power down and overheat!
¶ Verifying Motion
To test both RA and DEC, aswell as the function of the PC connections, download and install Stellarium. This is assuming a setup on Windows. Make sure it is set to your current time and location. To connect to the mount you will need the "Telescope" Plugin.
Connect OATcontrol through ASCOM, make sure it uses your current coordinates. Home the mount and press "set home".
If you now have Stellarium move the mount to a point, the mount should copy that motion. For example, if you set up the mount facing roughly north and select a point on the eastern horizon, the home location marker on the DEC axis should now also point east. Or, if you select the sun (assuming you do this during the day), it should point roughtly to the sun.
If not, you have either configured your mount wrong (the RA or DEC axis might be inverted), or either Stellarium or OAE doesn't have the correct time and/or location.
¶ Setting Up the OpenAstroExplorer
¶ Tripod setup
[Tripod adapter on EQ5]
¶ Mount unfolding and mechanical preparation
The ALT axis of OAE can be set to 4 distinct positions, each corresponding to a latitude range. The motorized motion of the axis then fine adjusts within the 10° of range.
When attaching, the M5 bolts that come out of the ALT axis slide into the slot. Insert them fully into the slot. Then tighten the ALT Knobs with a light tug.
¶ RA Ring & Belt tension
[RA Ring magnetics, belt attachment and tension]
¶ Attaching and balancing counterweights
[CW bar]
[CWs]
¶ Attaching imaging gear
[image telescope]
[image camera + Guider]
¶ Cabling & PC connection (link to Software/OATControl pages)
¶ Session Operation
Now that you have gone through the previous steps, you are ready for your first Astrophotography session! Just wait for the next clear night. As a general rule of thumb, the more new gear you aquired, the longer the clouds will linger over your place specifically. This is normal.
If you are completely new to the hobby, don't expect the first nights to result in APOD-worthy images. It remains one of the hardest things to do, capturing a few photons from thousands of lightyears away, from your light polluted backyard, with a tiny little lens or mirror.
If I can give you a tip, don't compare yourself to others. This also applies to life in general but is especially true to Astrophotography. There will always be someone with better (read: more expensive) gear and better processing technique.
¶ Connecting to PC and software
Above you have already gotten to know OATcontrol. This is the central Software for OpenAstroTech mounts. For a session, these are the bare minimum steps you need to take:
- Power up mount and connect USB
- Connect OATcontrol through ASCOM
- Verify Lat and Long for current position
- Home the mount and press "set home"
¶ AutoPA (Automated Polar Alignment)
OAE has the capability to do the Polar alignment route automatically. This can be done either through Sharpcap's Polar alignment routine (paid licence) or NINA's "Three Point Polar Alignment" Plugin, abbreveated TPPA.
Fully automated PA currently has two issues:
1: The TPPA routine is received by OATcontrol, but no corrections are issues. This is a known software bug.
2: The logging in Sharpcap is too slow to be useful. We are working with the Sharpcap team to resolve this issue.
You can also use the manual method for Polar Alignment with OAE. This is at least semi-automatic, as it doesn't require you to sit outside in the cold. OATControl has a "mini-control" button in the bottom left, which enables you to manually move the ALT and AZ axis. Together with that and NINA/Sharpcap, you can do the Polar alignment as with any other mount.
¶ Running guiding
The overall procedure for guiding is described on the Guiding page.
¶ Monitoring performance and making adjustments
¶ After the Session
- Safe shutdown procedure
- Disassembly and storage
- Protecting sensitive parts (electronics, 3D-printed parts)
¶ Troubleshooting & Common Issues
- Alignment errors (stars trailing)
- Belt tension problems
- Connection/software issues
- Mechanical stiffness or imbalance
¶ Additional Resources
- Links to detailed pages (Software, OATControl, Guiding)
- Community forums and Wiki contributions