NGC 4656 PHOTOMETRY DATA PAGE

(JPL/CSULA 2009 CAMPAIGN)

Overview: This CURE sponsored project will utilize the Wyoming 2.2 meter telescope

to perform aperture photometry on the SB(s)m pec galaxy NGC 4656

in Virgo at RA:12h 43m 57.7s Dec:+32° 10′ 05″


UV Image - GALEX Data	H-Alpha (656.3nm line)	H-Alpha + Radio - 4.85 GHz
	(From: Astronomy & Astrophysics - E.S.O.)
	Gridlines added by Jrf

Preliminary Target Assignments


Image by Jrf (11-12Mar2005) 0.3M from Mt. Pinos, California	H-alpha overlaid with Jrf Image and using Adobe PS Pinlight composite to show probable discrete HII & OB associations (Click for Larger Image)	H-Alpha (656.3nm line)

TARGET COORDINATES FOR OB & HII OBJECTS WITHIN NGC 4656

Object Designation	Right Ascension (J2000) Est.	Declination (J2000) Est.

OB1	12:43:49.0	+32:08:11
OB2	12:43:57.7	+32:09:52
OB3	12:44:08.0	+32:12:27
OB4	12:44:03.6	+32:12:59
HII-1	12:43:46.6	+32:07:43
HII-2	12:43:57.9	+32:08:10
HII-3	12:44:04.6	+32:11:46

Here are some important photometric formulas:

List of Pertinent Variables

SNR=κ*S*Q*t/SQRT(κSQt+{n_u})

κ= Transmittance of the system based on flux efficiency
S= Original Signal
Q= Quantum Efficiency
t(sec)= Exposure Time
n_u= Sum of all contributors for instrumental noise

Last Update: 03 March 2009

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