Date & Time: | Aug 15 2020, from 20:56 to 21:18 JST(+0900) |
Composed 6 shots with 3 minutes exposed | |
Optical: | AF zoom-Nikkor 80-200mmF2.8 ED (f=155mm, stop: F4.0) |
with Kenko Starry Night & Softon Clear filters | |
Auto-guided with Kenko SKYMEMO Equatorial | |
Digital Camera: | Nikon D810A |
Location: | Koumi town, Nagano pref. |
Camera Settings: | Recording Format...14bit CCD-RAW, converted to 16bit TIFF(7360×4912) |
Device Size...FX format(36×24mm) | |
Sensitivity...ISO800, White Balance...Daylight |
M7 (NGC6475) in lower left hand side is clearly the best open cluster of the constellation. This magnificent object is extremely large (about a size of 1 degree) and quite bright, being visible even to the naked eye at a viewpoint far from urban area. You will be impressed the splendid scenery of about 80 stars scattered in the Milky Way with binoculars. In fact, in the Messier's catalogue, M7 is positioned at the most southern point in the sphere, the culminate latitude of that is only about 20 degrees at Tokyo. And M7 is one of rare objects known before the telescope was invented, the cluster was found out by an ancient astronomer Ptolemy in 2nd century. This cluster has another name of "Ptolemy's Cluster". This image has been cropped with an equivalent focal length of 180mm. |
Hoag's Object |
M11 |
Copyright(c) 2020 by Naoyuki Kurita, All rights reserved. | |||
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