Astrophotography enthusiasts looking to automate their focusing procedure have a few options. You can either purchase an entirely new focuser kit that includes a motor (such as a MoonLite Focuser) or upgrade your telescope’s existing focuser with a stepper motor like the one available from Pegasus Astro.
The point of the upgrade or modification is to better control the focus of your telescope, which is especially important for astrophotography. There are many benefits to making this upgrade, but the most important aspect is to produce consistently sharp images with your DSLR or dedicated astronomy camera.
The Pegasus Astro Motorized Focuser Kit
In this video, I take you into the backyard for an imaging session using my latest telescope upgrade. I was able to control the telescope remotely from inside the house using Team Viewer on my imaging laptop out in the cold. The addition of a Pegasus Astro Dual Focus Motor controller means that I can now adjust my focus on the fly, without venturing back outside once everything is set up.
Benefits of a Motorized Focuser
I must admit, when I was first approached by Pegasus Astro to try out their stepper motor and dual motor focus controller, I only thought of the idea of focusing remotely. It wasn’t until I connected the focus motor to Astro Photography Tool that I realized I could do much, much more. Here are some of the main advantages of using a motorized focuser and controller:
- high precision control
- the telescope is not touched
- focus remotely using PC
- use “autofocus” features
- compensate for changes in temperature
There is really only one drawback in the upgrade, and that’s added hardware and wiring to your rig. That means another USB connection to your PC, and 2 more wires running to the telescope and mount. Those of you that own a personal observatory with a permanent setup are more likely to invest in an automated focus solution.
On the night of January 6, 2018, I used the Pegasus Astro DMFC to adjust the focus of my Explore Scientific ED 102 refractor from inside the house. This was accomplished by accessing my imaging laptop outside remotely using TeamViewer. The computer outside ran the focus motor controller, which was plugged into the stepper motor via a D-Sub connection.
The Focus Motor Controller allows me to make fine adjustments without going anywhere near the telescope.
The timing couldn’t have been better for this upgrade, as the outside ambient temperature dropped below -20 degrees Celcius. Once the mount was polar aligned and ready to go, all further imaging steps were taken remotely from in the house. This includes framing my target using Cartes Du Ciel to control the mount.
The stand-alone software that comes included with the Motor Controller works exceptionally well and is very straightforward. I watched the star size change using Live View in Astro Photography Tool until I reached a sharp focus with the Altair Hypercam 183M.
There are a number of ways to install the stepper motor and controller to your telescope. See more configurations on the Pegasus Astro website.
Below is a screenshot of the software I use to control the focus of my telescope. I found this application to be useful and responsive and was able to fine-tune my focus when looping a live-view 10-second exposure in APT. The DMFC will communicate directly within Astro Photography Tool, but I experienced some hiccups early on. More on this below.
Pegasus Astro Dual Motor Focus Controller
The Dual Motor Focus Controller (DMFC) was designed to maintain the optimal focus position during a night of imaging. I have yet to experience the advanced features of this controller and am currently using it in its most basic form.
It communicates with the motor from my PC application commands and includes the temperature probe for a reading of the ambient temperature in my backyard. It works the way it should, but I do not have anything to compare this to, as I have never owned a focus motor controller before.
Installing the Stepper Motor
The process of installing the stepper motor involved removing the focuser of my Explore Scientific ED102. This was something I had never done before and definitely felt a little strange. Imagine the feeling of disassembling a high-end telescope that you use almost daily.
The team at Pegasus Astro was quick to respond to the early questions I had about installing the stepper motor. The process will be straightforward to anyone who has ever upgraded a telescope focuser before but might be a little confusing to newbies of this procedure.
It is best to remove the stock focuser from the optical tube first, so you can access the tight spots you’ll need to get into better. You’ll only need 2 tools, a small Phillips head screwdriver, and an Allen key set.
Pegasus Astro offers step by step instructions for installing the focuser on their website.
Controlling the focuser on my PC
Although I successfully connected to the focuser using APT (Astro Photography Tool), I had some issues when using it to control the focuser. The focuser would only move one direction (outwards) no matter which command I sent. This is likely an issue due to an outdated version of APT, and/or lack of the proper settings.
Many others have had success using APT with the DFMC, and the team at Pegasus has been very helpful on this issue.
However, using the Pegasus stand-alone software for the focus motor controller worked like a charm. I simply leave this application running during my imaging session to control the focus. Having the ability to adjust the focus of my camera while sitting indoors still blows me away!
You’ll find the necessary software to run the camera on your PC here: http://pegasusastro.com/support/
The Pegasus Astro Stepper Motor Kit is an affordable way to upgrade your existing telescope with remote focusing abilities. This installation process was straightforward on my small refractor telescope, but owners of other telescope types and sizes will need to research the Pegasus Astro website to make sure a motor focus kit is a good option.
The image above was captured using the Stepper Motor Kit to focus the telescope
The Focus Motor Controller works as it should, and worked brilliantly with the standalone software provided with the kit. I expect others will want to integrate the focuser with their existing capture software such as APT or Sequence Generator Pro.
I’ll continue to share my experiences using the stepper motor kit and controller over the coming months. One thing is for sure, I appreciate the warm hands while focusing in this harsh Canadian winter we’re having!