Comparison of White-light & H-alpha at 3rd to 4th contacts (Jun 6, 2012)

Date & Time:	Jun 6 2012, Times are displayed in image
Optical (upper, white-light):	BORG 45EDII, afocal method with LV25mm eyepiece (Syn. f=793mm)
	with ND400, ND8 & ND4 filters (timely changed)
(lower: H-alpha):	Coronado SolarMax40, eyepiece projection with Naglar type5 16mm (f=1025mm, F26.0)
	Auto-guided with TAKAHASHI EM-200 Equatorial
Digital Camera:	Canon iVIS HF M41(white-light), Canon EOS 550D(Remodeled)(H-alpha)
Location:	Joetsu city, Niigata pref.

Camera Settings (White-light):	Mode...MXP(24Mbps), Aperture Value Manual
	Lens...f=61mm (equivalent f=436mm in 35mm film format), Stop: F3.0
	30 JPEG images (for 1sec.) captured each, stacked with Registax5.1

Camera Settings (H-alpha):	Recording format...14bit CCD-RAW, converted to 16bit TIFF(5184 x 3456)
	CCD sensitivity...ISO800

This page has displayed comparing images of Venus transit on Jun6, 2012 with white-light (upper column) and H-alpha light (lower column) taken at 13:31:04 JST(UT+9), just after the 3rd contact (left row) and at 13:47:30 JST, just after the 4th contact (right row).
At just after the 3rd contact, part of the Venus has already left from solar surface with white-light, but you can detect that the Venus looks perfect circle yet with H-alpha. At that time the Venus hasn't reached the outer edge of chromosphere surrounding solar disk, so such a difference can be observed. Similarly at just after the 4th contact, the Venus, indicated with an arrow, has almost perfectly left from solar disk with white-light, while a part of Venus has covered the chromosphere yet in H-alpha image. I could detect a shadow of the Venus for a few minutes longer with an H-alpha solar telescope.

Venus Transit with H-alpha (Jun 6, 2012)

Aureole effect of the Venus (Jun 6, 2012)

		Copyright(c) 2012 by Naoyuki Kurita, All rights reserved.
To top page	To Moon & Planets index