<p>I'm using python to calculate the thermal and reflected flux densities of a faceted asteroid model, where both equations have the Planck function present in them.</p>
<p>Currently, I'm integrating the Planck function over the bandpass of the filter. For instance, using the Spitzer Space Telescope's IRAC channel 2 filter, I'm integrating it with an effective wavelength of <a href="https://irsa.ipac.caltech.edu/data/SPITZER/docs/irac/iracinstrumenthandbook/6/#_Toc59022337" rel="nofollow noreferrer">4.493 microns with a bandwidth of 1.010 microns</a>. Is this correct way to do it, given this filter has a <a href="https://en.wikipedia.org/wiki/Top-hat_filter" rel="nofollow noreferrer">top-hat filter distribution</a>?</p>
<p>For the case, of the reflected flux density, I'm integrating it with the bandpass of the Johnson standard V filter with an effective wavelength of <a href="https://en.wikipedia.org/wiki/Photometric_system" rel="nofollow noreferrer">0.551 microns and a bandwidth of 88 microns</a>. However, this V filter has <a href="https://en.wikipedia.org/wiki/UBV_photometric_system" rel="nofollow noreferrer">Gaussian looking distribution</a>. How do I take this into account?</p>

CC BY-SA 4.0
2021-02-15T07:33:10.753Z
What information exactly are you trying to obtain?
planetmaker
CC BY-SA 4.0
2021-02-15T07:39:46.803Z
You might simply have to deconvolve your data with the spectral response of your filters
planetmaker
CC BY-SA 4.0
2021-02-15T07:45:08.487Z
@planetmaker I'm trying to calculate the spectral flux densities of asteroids at different wavelength regions, where at lower mid-IR wavelengths, I need to take into account reflected light. I know question makes it look like I'm calculating the thermal and reflected light at different wavelength regions, but this is just for the validation of my code, before I combine them at the same wavelength regions.
Rahoul
CC BY-SA 4.0
2021-02-15T07:56:38.043Z
@planetmaker Do you know where I can get the spectral responses of those filters? I'm sorry if this is straightforward knowledge, but this is not my background.
Rahoul
CC BY-SA 4.0
2021-02-16T17:12:23.500Z
The [Filter Profile Service](http://svo2.cab.inta-csic.es/theory/fps/index.php?mode=browse&gname=Spitzer&asttype=) of the Spanish Virtual Observatory should have what you need
astrosnapper
CC BY-SA 4.0
2021-02-17T17:27:01.723Z
@astrosnapper Thank you!
Rahoul
<photometry><modeling>
How to take into account the filter response in thermal and reflected flux density calculations?
Rahoul
# How to take into account the filter response in thermal and reflected flux density calculations?

(Asked by: username_0 on 2021-02-15)

I'm using python to calculate the thermal and reflected flux densities of a faceted asteroid model, where both equations have the Planck function present in them.

Currently, I'm integrating the Planck function over the bandpass of the filter. For instance, using the Spitzer Space Telescope's IRAC channel 2 filter, I'm integrating it with an effective wavelength of [4.493 microns with a bandwidth of 1.010 microns](https://irsa.ipac.caltech.edu/data/SPITZER/docs/irac/iracinstrumenthandbook/6/#_Toc59022337). Is this correct way to do it, given this filter has a [top-hat filter distribution](https://en.wikipedia.org/wiki/Top-hat_filter)?

For the case, of the reflected flux density, I'm integrating it with the bandpass of the Johnson standard V filter with an effective wavelength of [0.551 microns and a bandwidth of 88 microns](https://en.wikipedia.org/wiki/Photometric_system). However, this V filter has [Gaussian looking distribution](https://en.wikipedia.org/wiki/UBV_photometric_system). How do I take this into account?

**Tags:** photometry, modeling
> **Comments:**
> **username_1**: What information exactly are you trying to obtain?  
> **username_1**: You might simply have to deconvolve your data with the spectral response of your filters  
> **username_0**: @planetmaker I'm trying to calculate the spectral flux densities of asteroids at different wavelength regions, where at lower mid-IR wavelengths, I need to take into account reflected light. I know question makes it look like I'm calculating the thermal and reflected light at different wavelength regions, but this is just for the validation of my code, before I combine them at the same wavelength regions.  
> **username_0**: @planetmaker Do you know where I can get the spectral responses of those filters? I'm sorry if this is straightforward knowledge, but this is not my background.  
> **username_2**: The [Filter Profile Service](http://svo2.cab.inta-csic.es/theory/fps/index.php?mode=browse&gname=Spitzer&asttype=) of the Spanish Virtual Observatory should have what you need  
> **username_0**: @astrosnapper Thank you!  

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## 0 answers

