Messier 71 is a globular cluster located in constellation Sagitta. The cluster is located approximately 12 – 13 thousand light-years from earth. The classification of M71 as a globular cluster was questionable for a long time, because it lacks central star concentration and therefore it was considered as an open cluster. The diameter of this cluster is only 27 light-years, which is very low value for globular cluster.
Well I am back in light pollute sub-urban area. I can use bigger and heavier telescope, but I am missing dark skies of Milos. The picture is an integration of 38 pictures, with exposure time 3 minutes. Total exposure time was approximately 2 hours.
I managed to test new TS-Optics 2″ 3-element MaxField Newtonian Coma Corrector, which should be 2” version of Wynne corrector. It should have significant advantage compared all 2” coma correctors on the market: it reduces focal length by 5%, should correct full frame CCD (we will see about that) and it should have very low vignetting. I will have to extend my World Wide Coma Correction exercise.
|Telescope||Newton 254/1000 mm|
|Focal length||950 mm|
|Autoguiding||ZWO 174MM, TS 60/240 mm|
|Camera||ZWO 071 Pro @-15C|
|Corrector||TS-Optics 2" 3-element MaxField|
|Filters||Hutech IDAS LPS-D2|
|Exposure||38x180s, Gain 94, bin 1x1,|