Push-to apps use the technology of a smart phone to guide you to targets.
Astrohopper is an open source web app that get good user views. It’s more accurate than SkEye.
SkEye is an app that like the excellent Stellarium allows you to find objects in the sky. It dispenses with ‘bells and whistles’ so there are no pretty constellation images but that functionality suits me fine. With a phone attached to the tube of my telescope, it also has the advantage of what is termed Indirect mode. Indirect mode allows me to locate objects using “push-to” so what I see on the screen is what I (should) see through the eyepiece.
I became more proficient in using SkEye to locate objects over time as I got to know its quirks and foibles.
For finding dim and difficult objects, I also use this method.
- I use a phone mount that I purchased for cycling. It used to be attached to the EP tube of my straight-through finder. As I now have a RACI, I attach the mount using a 1 metre cable tie.
- I have tried using the phone so that screen points upwards (as in the picture) and also towards the eyepiece (in landscape mode) so it is facing me. The latter makes scanning a bit of the sky to see what is there very easy. I have found a number of DSOs and binaries “by accident” in this way.
- The initial alignment was made using three easy to find objects. For example Arcturus, Mars, Castor and Polaris.
- After a period of use, I use the Insta-align function when I have acquired an object to improve accuracy.
- I still use the straight-through finder but not as often; so my back is grateful. I have a Telrad and use this to check that SkEye isn’t way off. The finder is used if an object doesn’t come into view of my WA 42mm EP.
- When I get dew or ice on my Telrad or finder, SkEye has been my only tool and has come to the rescue.
- The Telrad, finder, wide-angle (low power) eyepiece and SkyEye work together.
- SkyEye has its quirks. It can suddenly jump a few degrees but does seem to “find itself” again. I have not any stray magnetism warnings due to the metal OTA but this could be the cause of the jumping. User reviews indicate that
- Astrohopper doesn’t suffer the above limitations.
Update following a period of use
Alignment is very quick using a couple of good targets and then an insta-align “check” to keep things precise.
It can sometimes “forget where it is”, but a second later it catches up and it is often spot on target. I keep the magnetometer calibrated with a figure of 8 calibration. The author has an app for calibrating the magnetometer (instructions) and I find this works well.
I also tried using an old Samsung A3 phone rather than my main one (OnePlus 8 Pro) and although the screen is noticeably smaller it works fine once calibrated.
A major plus is that unlike my Telrad and finder scope it doesn’t suffer from dew or ice!
Given that the app was free, in order to support the developer (who offers brilliant support) I bought the Pro version (about £8) which has more objects and also allows me to add my own database of binary stars.
I’ve now changed the finder to a right angle type (RACI), so I now star hop to find objects as I find that method quick and efficient. This is particularly the case for galaxies and fainter nebulae.
If you are interested in using technology to find objects
, I’d recommend looking at Astrohopper as well as SkEye.