the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 10 Jul 2023
Multi-star calibration in starphotometry
Liviu Ivănescu
Norman T. O'Neill
Abstract. We explored the improvement in starphotometry accuracy using a multi-star Langley calibration in lieu of the more traditional one-star Langley approach. Our goal was a 0.01 calibration-constant repeatability accuracy, at an operational sea-level facility such as our Arctic site at Eureka. Multi-star calibration errors were systematically smaller than single star errors and, in mid-spectrum, approached the 0.01 target for an observing period of 2.5 h. Filtering out coarse mode (super µm) contributions appears mandatory for improvements. Spectral vignetting, likely linked to significant UV/blue spectrum errors at large airmass, may be due to limiting field-of-view and/or sub-optimal telescope collimation. Starphotometer measurements acquired by instruments that have been designed to overcome such effects may improve future star magnitude catalogues and consequently starphotometry accuracy.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
(1989 KB)
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(1989 KB) - Metadata XML
- BibTeX
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- Final revised paper
Journal article(s) based on this preprint
Liviu Ivănescu and Norman T. O'Neill
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2023-1383', Anonymous Referee #1, 15 Aug 2023
The paper is quite interesting and certainly should be published.
Authors explored the improvement in starphotometry accuracy using a multi-star Langley calibration in lieu of the more traditional one-star Langley approach. Multi-star calibration errors were systematically smaller than single star errors.
The paper is clearly written, concise and figures visualize major findings. All parts are very well organized and structured. I would like to emphasize that iron logic in data presentation is a very rare beast these days. Therefore, I would support paper acceptance.
The paper underlines the starphotometry potential in aerosol optical studies. Appendices are very important for thorough reader, providing many specific details regarding component errors and calibration opportunities.
Citation: https://doi.org/10.5194/egusphere-2023-1383-RC1 -
AC1: 'Reply on RC1', Liviu Ivanescu, 25 Oct 2023
We appreciate the holistic and clearly experienced overview of the paper, as well as the attentiveness with which the reviewer must have applied when reading through the paper.
Citation: https://doi.org/10.5194/egusphere-2023-1383-AC1
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AC1: 'Reply on RC1', Liviu Ivanescu, 25 Oct 2023
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RC2: 'Comment on egusphere-2023-1383', Anonymous Referee #2, 18 Sep 2023
This paper presents the advantages of the multi-star Langley calibration in starphotometry. This is a very interesting topic because it will make easier the operation of starphotometry in high altitude places. The paper is very-well written, and as the other referee indicates, the iron logic is quite appreciated. I also highlight that the paper is very concise which sometimes is missing in other publications full of sentences that only has sense for promoting self-citations. Definitely, the current paper follows the structure of a scientific paper and I recommend its publication in AMT
Apart of that, the results are quite interesting in improving the capabilities of star-photometry for aerosol studies. I only have minor comments that the authors could take into account for improving the manuscript
If the reader is not familiar with star photometry and previous publications by the authors, following the derivations of Eqs. 1 and 2 can be difficult. Just a very brief explanation can help.
The other point is about what are the star catalogues currently available, their spectral resolution and if they are public available. Again a brief discussion could help. Finally, I believe that a brief explanation of the instrument used for acquiring the data is needed.
Citation: https://doi.org/10.5194/egusphere-2023-1383-RC2 -
AC2: 'Reply on RC2', Liviu Ivanescu, 25 Oct 2023
The referee’s comments are presented in italic and our answers are written in plain text. Modifications of the manuscript, if any, are written in plain bold text.
We thank the referee for the in-depth and careful evaluation. The specific actionable points that were brought up (in italics) are addressed below. Please note that line numbers are in reference to the reviewed manuscript.
1. “If the reader is not familiar with star photometry and previous publications by the authors, following the derivations of Eqs. 1 and 2 can be difficult. Just a very brief explanation can help.”
The reviewer will appreciate that the intent of this multi-star calibration paper is to follow on the heels of the comprehensive “Accuracy in starphotometry” paper (Ivanescu et al., 2021): in citing that paper we are also indicating where the reader can find the type of fundamental explanation that the reviewer is asking for.
To make that point clearer, we changed the lines 34-35 from: “(see Ivanescu et al. (2021) for the nomenclature details)” to “(see Ivanescu et al. (2021) for a more comprehensive elaboration of this section).”
We also made the following changes (lines 35-36): “Their corresponding (instrument) signals, expressed in terms of magnitude (logarithmic) formulation, are S0 and S, respectively.” was changed to “Their corresponding instrument signals, expressed in terms of magnitude, are S0 = -2.5 log F0 and S = -2.5 log F, respectively, with F0 and F being the actual measurements in counts/s.”
2. “The other point is about what are the star catalogues currently available, their spectral resolution and if they are public available. Again, a brief discussion could help.”
We appeal to the fact that catalogue information is also thoroughly described in Ivanescu et al., (2021). To better emphasize the availability of this information elsewhere, we changed line 63 from: “see Ivanescu et al. (2021) for a detailed discussion of error bias in the catalog stars” to “see Ivanescu et al. (2021) for a detailed discussion of error bias in the Pulkovo and other catalogues.”
To specify our specific catalog, line 34 was changed from: “M0 (provided by a catalog)” to “M0 (provided by the Pulkovo catalogue of Alekseeva et al. (1996))”.
3. “Finally, I believe that a brief explanation of the instrument used for acquiring the data is needed.”
We again appeal to the fact that our Eureka instrument was extensively described in Ivanescu et al. (2021). We complemented that information by changing the lines 17-19 from “Eureka, NU, Canada (Ivanescu (2015), Baibakov et al. (2015), Ivanescu et al. (2021)).” to “Eureka, NU, Canada (Ivanescu (2015), Baibakov et al. (2015), Ivanescu et al. 2021)), using a commercial spectrometer-based starphotometer1, attached to a Celestron C11 telescope.”
1made by Dr. Schulz & Partner GmbH (currently closed).
We also added a reference to our initial instrument development (Gröschke et al., 2009) in a general sentence about historical starphotometer developments. The following sentence was therefore inserted after the 1st sentence of the Introduction: “Dedicated instrument development had already begun in the late 1950s (Dachs 1960; Dachs et al., 1966, Dachs, 1966), with increased activity after 2000 (Théorêt, 2003; Gröschke et al., 2009; Pérez-Ramírez, 2010; Oh 2015}.”
Citation: https://doi.org/10.5194/egusphere-2023-1383-AC2
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AC2: 'Reply on RC2', Liviu Ivanescu, 25 Oct 2023
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2023-1383', Anonymous Referee #1, 15 Aug 2023
The paper is quite interesting and certainly should be published.
Authors explored the improvement in starphotometry accuracy using a multi-star Langley calibration in lieu of the more traditional one-star Langley approach. Multi-star calibration errors were systematically smaller than single star errors.
The paper is clearly written, concise and figures visualize major findings. All parts are very well organized and structured. I would like to emphasize that iron logic in data presentation is a very rare beast these days. Therefore, I would support paper acceptance.
The paper underlines the starphotometry potential in aerosol optical studies. Appendices are very important for thorough reader, providing many specific details regarding component errors and calibration opportunities.
Citation: https://doi.org/10.5194/egusphere-2023-1383-RC1 -
AC1: 'Reply on RC1', Liviu Ivanescu, 25 Oct 2023
We appreciate the holistic and clearly experienced overview of the paper, as well as the attentiveness with which the reviewer must have applied when reading through the paper.
Citation: https://doi.org/10.5194/egusphere-2023-1383-AC1
-
AC1: 'Reply on RC1', Liviu Ivanescu, 25 Oct 2023
-
RC2: 'Comment on egusphere-2023-1383', Anonymous Referee #2, 18 Sep 2023
This paper presents the advantages of the multi-star Langley calibration in starphotometry. This is a very interesting topic because it will make easier the operation of starphotometry in high altitude places. The paper is very-well written, and as the other referee indicates, the iron logic is quite appreciated. I also highlight that the paper is very concise which sometimes is missing in other publications full of sentences that only has sense for promoting self-citations. Definitely, the current paper follows the structure of a scientific paper and I recommend its publication in AMT
Apart of that, the results are quite interesting in improving the capabilities of star-photometry for aerosol studies. I only have minor comments that the authors could take into account for improving the manuscript
If the reader is not familiar with star photometry and previous publications by the authors, following the derivations of Eqs. 1 and 2 can be difficult. Just a very brief explanation can help.
The other point is about what are the star catalogues currently available, their spectral resolution and if they are public available. Again a brief discussion could help. Finally, I believe that a brief explanation of the instrument used for acquiring the data is needed.
Citation: https://doi.org/10.5194/egusphere-2023-1383-RC2 -
AC2: 'Reply on RC2', Liviu Ivanescu, 25 Oct 2023
The referee’s comments are presented in italic and our answers are written in plain text. Modifications of the manuscript, if any, are written in plain bold text.
We thank the referee for the in-depth and careful evaluation. The specific actionable points that were brought up (in italics) are addressed below. Please note that line numbers are in reference to the reviewed manuscript.
1. “If the reader is not familiar with star photometry and previous publications by the authors, following the derivations of Eqs. 1 and 2 can be difficult. Just a very brief explanation can help.”
The reviewer will appreciate that the intent of this multi-star calibration paper is to follow on the heels of the comprehensive “Accuracy in starphotometry” paper (Ivanescu et al., 2021): in citing that paper we are also indicating where the reader can find the type of fundamental explanation that the reviewer is asking for.
To make that point clearer, we changed the lines 34-35 from: “(see Ivanescu et al. (2021) for the nomenclature details)” to “(see Ivanescu et al. (2021) for a more comprehensive elaboration of this section).”
We also made the following changes (lines 35-36): “Their corresponding (instrument) signals, expressed in terms of magnitude (logarithmic) formulation, are S0 and S, respectively.” was changed to “Their corresponding instrument signals, expressed in terms of magnitude, are S0 = -2.5 log F0 and S = -2.5 log F, respectively, with F0 and F being the actual measurements in counts/s.”
2. “The other point is about what are the star catalogues currently available, their spectral resolution and if they are public available. Again, a brief discussion could help.”
We appeal to the fact that catalogue information is also thoroughly described in Ivanescu et al., (2021). To better emphasize the availability of this information elsewhere, we changed line 63 from: “see Ivanescu et al. (2021) for a detailed discussion of error bias in the catalog stars” to “see Ivanescu et al. (2021) for a detailed discussion of error bias in the Pulkovo and other catalogues.”
To specify our specific catalog, line 34 was changed from: “M0 (provided by a catalog)” to “M0 (provided by the Pulkovo catalogue of Alekseeva et al. (1996))”.
3. “Finally, I believe that a brief explanation of the instrument used for acquiring the data is needed.”
We again appeal to the fact that our Eureka instrument was extensively described in Ivanescu et al. (2021). We complemented that information by changing the lines 17-19 from “Eureka, NU, Canada (Ivanescu (2015), Baibakov et al. (2015), Ivanescu et al. (2021)).” to “Eureka, NU, Canada (Ivanescu (2015), Baibakov et al. (2015), Ivanescu et al. 2021)), using a commercial spectrometer-based starphotometer1, attached to a Celestron C11 telescope.”
1made by Dr. Schulz & Partner GmbH (currently closed).
We also added a reference to our initial instrument development (Gröschke et al., 2009) in a general sentence about historical starphotometer developments. The following sentence was therefore inserted after the 1st sentence of the Introduction: “Dedicated instrument development had already begun in the late 1950s (Dachs 1960; Dachs et al., 1966, Dachs, 1966), with increased activity after 2000 (Théorêt, 2003; Gröschke et al., 2009; Pérez-Ramírez, 2010; Oh 2015}.”
Citation: https://doi.org/10.5194/egusphere-2023-1383-AC2
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AC2: 'Reply on RC2', Liviu Ivanescu, 25 Oct 2023
Peer review completion
Post-review adjustments
Journal article(s) based on this preprint
Liviu Ivănescu and Norman T. O'Neill
Liviu Ivănescu and Norman T. O'Neill
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(1989 KB) - Metadata XML