Photometry Definition and 22 Threads

why dna absorbs best at 260nm?

Hello, I have the demonstration below. A population represents the spectroscopic proble and B the photometric probe. I would like to know if, from the equation (13), the correlation coeffcient is closed to 0 or to 1 since I don't know if ##\mathcal{N}_{\ell}^{A}## Poisson noise of spectroscopic...

I would like to try the photometric transform given in my book, for instance ##V = y - 0.12[(b-y) - 0.55]^2##, however, the two catalogs I've consulted, Paunzen, 2015 and Hauck, 1997 only provides the indices. Do these catalogs provide the uvby magnitudes as well, just hidden somewhere? Are...

I have found the difference in the magnitude from the counts to be -.073 using -2.5log(11347/10606) but I m unsure if this is right or how to calculate the uncertainty

For example suppose the uncorrected extinction instrumental magnitude is ##v^A_V = 9.00##, will the corrected extinction instrumental magnitude always be greater than ##9##?

I have been trying to calculate what retinal irradiance value I get with a 1 blue LED system. Since the manufacturer didn´t give the spectral distribution information, I will approximate LED as a monochromatic one (using the 460 nm peak). From the datasheet, the LED intensity range goes from 6...

Hello everyone, As my first post in this forum, i want to ask two questions, mainly out of personal interest, concerning the possibilities of transit photometry in detecting exoplanets: For larger planets or planets orbiting farther away from the host star, the measured drop of intensity...

What are the math concepts I have to learn for Radiometry, Photometry and Thermodynamics (all Calculus-based) as applied in building science (engineering, architecture, etc.). I'm almost done with Multivariable Calculus and I'm aware that MV Calculus is necessary, but what specific calculus...

Hi there, I am new to the Forum! I have a little bit of a tricky Problem. I am trying to calculate the Contrast between two planes as seen here: So I started by cutting the Problem in two Parts. Part 1, The Monitor: I know the Luminance of the Monitor X, and the reflectivity of the...

Learning Radiometry, Photometry, Optics, Thermodynamics, Fluid Mechanics(Statics & Dynamics) with great resources. I'm looking for resources for understanding the topics above. I prefer video tutorials as opposed to books but I couldn't find any video resources on Photometry and Radiometry (I...

Homework Statement The apparent total magnitude of a triple star is ##m_0 = 0,0##. The apparent magnitudes of two of its components are ##m_1 = 1,0## and ##m_2 = 2,0##. What is the apparent magnitude of the third component? Answer: 0,9 Homework Equations Since according to Norman Pogson...

I came to know that the PACS instrument of HERSHEL has a resolution of 5" at a scan speed of 20''/sec whereas it's 10'' at 60''/sec. The resolution has almost doubled with the scan speed. Can you please tell me why it's so?

I've been looking for a way to do photometry cheaply (variables and standards). I have no interest in eyepiece observations of the night sky or astrophotography. I am currently considering purchasing this...

I have been working with some Herschel images and I am finding it difficult to extract the astronomical sources from the image. The image background is extremely non uniform so i am not able to differentiate between the background and the source. I used some tasks in HIPE like source extractor...

CCDs are very cheap, but I was wondering if there was an even cheaper alternative to CCDs if the goal is differential photometry on magnitude 5 and under stars. The data only needs enough precision to prove/demonstrate the concept, and to develop a good sense of the workflow in doing...

Hi, it seems astronomical FITS images are abundant on the internet. However, I am looking for FITS images of bias/flat and standard stars along with observations to practice CCD photometry and having a harder time. I would like to be able to take a set of images and obtain the transformation...

Hello, I am trying to understand the concepts of photometric and radiometric measurements in an electronic sensor. Various photo sensors based on CCD (Charged Coupled Devices) or CMOS photo diode array technology are available in the market for measurements in Visible Spectrum. Now I want to...

Homework Statement By performing CCD photometry on a pair of nearby stars A and B we obtain their relative magnitudes in the V filter and their colors: Star A: mV = 8.70 , (B − V )= 1.30 Star B: mV = 11.90 , (B − V )= 1.81 Star A is known to be a of a main sequence K0V type, while no other...

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Does anyone have any idea how to get the photometry of SDSS data?

What do the letters stand for? Blue, Violet, Red, Indego? Does anyone have a link explaining the process? Google only seems to give articles describing results from using the technique without explaining what the technique is.

Hey guys (and girls) I've got a rather annoying question. If you were given the radiant power (45 mW) and luminous flux (22 l), and then was told it was spread uniformly spread over a hemisphere. (a) how do find the luminous intensity??, (b) the illuminance 1.8m away, and (c) illumance 5.0...