All:
Bottom Line:
The eFinder is an AWESOME SYSTEM THAT WILL TAKE YOUR OBSERVING TO ANOTHER LEVEL!
Intro:
I was asked to share my personal experience with the eFinder plate solving system developed by Keith Venables http://www.astrokeit...ipment/efinder/. The eFinder is a build it yourself plate solving system that integrates with Nexus, Nexus/Servocat, and other similar systems. As you may have inferred from the above statement, I am very happy with my eFinder. I have this system installed on my 25f/4 dob (w/ Nexus/Servocat). The pointing accuracy of my telescope prior to the eFinder install was quite good, but there were still times that I had to do a spiral search to find and center the object. Which is completely normal and expected.
Why:
What the eFinder enables you to do is have a refined (extremely accurate) goto, called a Goto++. Following the initial goto which usually places the object inside the FOV of a 6 Ethos in my 25f/4. Very impressive. This enables me to use smaller FOV eyepieces if desired and also go after more threshold objects. Why more threshold objects... because I know they are there. If needed (ex comets), I can memorize a smaller star pattern in that tight field and boom; there is that faint object you were chasing down. Plate solving only takes about 1 second or so to complete, that is correct ONE SECOND to complete a plate solve then command the Goto++ and enjoy the view because it is in the FOV! No external connection required; everything is standalone and resides on the scope.
Easier Alignment Than Nexus Alone:
The setup of the eFinder is super easy. What I do is first start by pointing my scope at Polaris. Then, I center on Polaris using a crosshair or just eyeball the center in a high power field (3.7 ethos). There is then a function in the eFinder to ID what the scope and eFinder are pointing at. Select this function (OK Bright Star), press OK, and in a few seconds (~3) it says Polaris. This aligns the telescope with the eFinder camera. Next, point the telescope at two different random parts of the sky and do a plate solve at each location (OK Aligns) and that is it. Your Nexus/eFinder system is aligned and you are off to the races!
The Build:
We built these as part of a group build in my club (ChesMont Astronomical Society). There were eight of us that built eFinders and 6 are currently operational right now; the others are not too far behind. One member of this build team, Steve, designed 3D printed cases for both the Pi and the hand control. These made the build much easier. They are really slick and incorporate all of the necessary components quite nicely. Steve worked very closely with Keith Venables and is authorized to build and sell eFinders, so if you are looking for a turn key solution, please reach out to Steve (I asked him to reply to this thread below).
Power Usage:
I do find myself using a bit more power in a given night, but why is this... yeah, there is the power draw of the Pi and eFinder, but this is not the reason why. I find myself slewing much more in a given night. You will see many more objects in a night. And you are not having to refer to start charts and/or using lights to see them. So this is what I call a nice problem to have.
The "What If" Scenarios:
I have not encountered this, but I did test for it just in case. What if the eFinder stopped working during an observing session? No big deal; you will still have the baseline functionality of your Nexus-enabled scope. The push to or go to accuracy will be the same as a non-eFinder equipped scope. And if the eFinder is not working, it will not prevent you from using the Nexus or Nexus/Servocat systems. But you will surely miss that eFinder if it is not working.
Summary:
I have been dreaming for YEARS about getting plate solving on one of my Dobs. One night of insomnia and some internet searching, I stumbled across Keith's website. Immediately wrote to him... and a few months later, I am sitting here writing this summary about how my experience is with a plate solving Dob.
I will ask others in my build group to chime in on this thread to share their experiences, but they are somewhat like me, been members on CN for years but rarely post.
Hope this helps,
Jack
