i wanted an inexpensive android device which I could use with skysafari 6 plus app to control my Wi-fi Celestron 6SE. Wanted to be able to hold the device in one hand (so 7-8 inch). Also wanted gyro and compass, enough space (for this and normal other apps) and enough oomph to run this app, 2.4Ghz Wi-fi and > android 4.4. Looked at the secondhand market (eBay) and found lots of used Samsung galaxy tab s2. I selected a used Samsung galaxy sm-t713 which had everything everything I wanted. 2.4 and 5Ghz Wi-fi, 8 inch screen, 32GB (expandable with microsd up to 128GB), android v7 with inbuilt compass and gyro. Picked it up for £100 and there were quite a few second hand Samsung tab s2 around this price point. Delighted to report works very well with skysafari plus to control my Celestron 6SE and all for around £100. Bought a case for it that has straps so can put around my neck. Perfect relatively cheap solution (for me).