Don't worry, though. I'm continuing the focus on Mars anyway!
One of the frustrating things about using a telescope at high magnification is getting perfect focus on an object.
Touch the focus knob to give it a twist and you'll impart vibrations on what you are seeing through the eyepiece or the imager . . . Wait a few seconds for the image to stop shaking, evaluate the focus and try again. And again.
Change magnification by swapping the eyepiece or the imager? You'll need to adjust focus again. And again.
I've mitigated this with a DIY project to add electronic control of the stock focuser that came with my SkyWatcher.
Here is a photo of the focus controller's display showing the temperature, focus tube position, and bar graph of relative position. The display is covered with dew, hence the streakiness of the photo -- pointing out the importance of water resistance in astro gear. 🙂
|Focuser OLED Display
The display will stay illuminated while the focus tube is moving and will timeout after a few seconds of the tube stopping.
The OLED display actually can show 65k of colors, but I chose a pale orangish red to help preserve my night vision when looking at it.
|One of Two Focus Motors. Thin Plywood Mount.
Here is a short video clip showing the stepper motors in action.
But sometimes, it is easier to get the best focus by using other means.
This illustrates the importance of having third party support for the focuser. It is really important in the early morning hours when you are trying to achieve optimum focus on an object and you are tired and grumpy from being up all night. 😏
Take a look at how I used SharpCap to get Mars in focus:
|SharpCap and AutoFocus, May 26th, 2018
The telescope was pointed at Mars and the ZWO ASI224MC imager was in place and attached to the laptop and plugged into a USB3 port. SharpCap was connected to the focus controller via Bluetooth link. It moved the focus tube outward and then inward while evaluating the contrastiness of the object in the green box (Mars.) It then determined the point of optimum focus and subsequently moved the focus tube to that position.