Observing August 9 and 10, 2023

August 9: Testing the eFinder

August 9 was (finally) a clear night in Belgium.  During our holidays to Italy,  I did not take my telescope, because there is a lot of light pollution at the locations we visited.   I started observing at 23:30 and finished around 1:30.  The temperature dropped from 12.7°C  to 10.7°C, while the humidity increased from 85% to 92%.  The night was quite humid, but the dew control was working without problems.  The SQM was 20.28, which is a decent value for our garden.

Since September last year, I am building a eFinder (see AstroKeith's pages, GitHub).  I am preparing a separate blog post on the eFinder later this year (or the beginning of next year), but I need to do some extra tests firsts.  This observing session was used to do a lot of tests with the eFinder.  

The eFinder is a small RaspBerry Pi computer, with an ZWO ASI camera attached to it. A small handpad is used as user interface (a VNC connection to the RaspBerry Pi is also possible).  The ServoCAT is still used to drive the telescope, in combination with the Nexus DSC Pro.  The Nexus DSC Pro has a small problem with the WiFi connection, so it was not possible to use SkySafari in combination with this setup.  It is possible to use the eFinder together with SkySafari, but a USB cable from the eFinder to the Nexus DSC Pro is needed to make that work.  As I did not have that cable yet, my tests were without a SkySafari connection.  

 This was the configuration:

After the telescope is moved to the requested object, the object is not always centered in the field of view of the telescope (sometimes, the object is not even in the field of view! Especially when using higher magnifications).  The eFinder does a plate-solve and send the offset back to the Nexus DSC / ServoCAT to make sure the telescope will center on the object. 

The eFinder worked very well and I could look at 20 different objects which were always in the field of view of the telescope.  I observed the following objects (but I did not take real notes, as I was testing the eFinder): M 13, NGC 6207, NGC 6888, NGC 6992, NGC 6960, NGC 7331, M 15, M 103, M 52, NGC 7789, M 81, M 82, M 56, M 57, M 71, M 92, M 102 (Bright and elongated, very nice object which I should observe in more detail), M 2 (which was brighter than expected), and M 27.

August 10: Extra tests

I installed the newest version of the eFinder and could repeat the tests again.  I did not write down anything, but I was very happy with the performance of the eFinder.  After correcting the location with the eFinder, the objects were always in my 8mm Tele Vue Ethos eyepiece (the ServoCAT never really keeps the object at 0.0, 0.0 in the Nexus DSC Pro, so I guess this is as good as it gets).