Thursday, May 10, 2018

POU 3855 in colour

Assembled the LRGB data for the multi-star system POU 3855, near alpha Vul, using the image files captured on 13 Sep '16. Colourful!

multi-star system POU 3855 in colour

Luminance 10x10, RGB 10x5 each. FITS Liberator 3, Photoshop CS2.

POU 3855 A is pale orange. The B star to the north-west is a deep orange, almost red. The C companion opposite, south-east, is hard to tag. I want to say purple! It can't be. Is it blue? Is it orange? Is it grey? Wow. Even zoomed in I find it hard to tell.

α Vul A looks light gold or citrus; B seems light blue or blue-white. This pair is aka STF A 42.


That gaggle of stars between POU 3855 and alpha is pretty compelling. Dove into the Washington Double Star database.

Found POU 3851. A pair of stars first discovered in 1892. Current position angle is 206° with a separation of 14.0. The WDS says they are magnitudes 11.3 and 11.6 respectively. This is the pair of blue stars almost vertically oriented due west of 3855, close to the orangey-yellow medium-bright star. SkyTools 3 Pro shows A is PPM 109089 (10.8) while B is GSC 02129-0016 (12.8). While the mags are off, the PA and sep are spot on. In the image, A is cyan blue; B is a dusty dull blue. Almost slate blue.

Found POU 3848. This is a very faint pair of stars from 1906. The current PA is 68 with a sep of 13.1. The WDS mags are 14.3 and 14.8. In ST3P, the bright star is known as J192837.16+243632. The PA and sep match. ST3P shows brightnesses of 14.5 and 15.0. In the image, this is the dim pair east-south-east of the medium bright equal pair of blue stars. A is light blue or grey; I don't get any colour off B.

Found POU 3850. Another pair from 1906. PA 71, sep 10.1, mags 12.6, 13.6. ST3P does not show stars at this location. The location, between GSC 02129-1026 and GSC 02129-0782, matches the image. Two equal stars in terms of colour, dull orange. A is slightly brighter to the south-west. Almost the same alignment and sep as 3848. Tighter the 3848.

Very interesting. And it still seems there are more doubles in the field...

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