PHOTOMETRYPIPELINE

In the framework of the MANOS program, I have been working on an automated data analysis pipeline for calibrated asteroid photometry and astrometry from imaging data. This pipeline, which can be applied to any kind of point source observations, is now in a robust state and available through github.

For details on the pipeline, please refer to Mommert 2017 (in press at Astronomy and Computing, arxiv).

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Observing Tools

A while back, I wrote some tools that I use for planning my observations. Now, I finally found the time to update them and turn them into publicly accessible websites. The tools are:

Observation Planner

This tool plots visibility curves indicating target elevation and airmass over the course of a whole night, which is either the current or coming night, or any night the user selects.  A number of moving and fixed targets can be displayed in the plot at a time, as shown in the example below. The purpose of this tool is to make it easier to decide which object to observe next. The black vertical represents the current time; dusk and dawn are also shown.

obsplan

Pointing and Finder Tool

The idea behind this tool is to minimize the time necessary to obtain coordinates for moving targets and to create a finder chart to identify the target. Simply enter the target name and a time – or just select the current time – and the tool will provide pointing information including RA, Dec, the target’s rates, visual brightness, and airmass, as well as a finder chart indicating the target’s position at different times (see below). The tool can also be used to generate finder charts for fixed targets.

nextpointing

 

Both tools are currently set up for only a small number of observatories. If you would like to use these tools for your own observations, let me know and I can add your favorite observatory. Also, don’t hesitate to contact me if you have any other suggestions or comments!

Rapid-Response Spectrophotometric Observations of NEOs with UKIRT and RATIR

The understanding of the compositional distribution of NEOs is important to reconstruct their dynamical and physical evolution, assess the damage potential in case of an impact, and estimate the resources that can be obtained from these bodies in the not-so-far future. Also, there is still a discrepancy between the compositional distribution of meteoritic material found on Earth and the overall composition of the NEO distribution.

The most common way to investigate the compositions of asteroids is to perform spectroscopic observations: wavelength-dependent variations of the surface reflectance can be diagnostic for the composition of an object and allow for a taxonomic classification. However, spectroscopic observations are usually only possible for bright and large asteroids and require large telescopes for small asteroids.

By applying a special observing mode and strategy, we are able to constrain the taxonomic classification of even the smallest NEOs.

Most NEOs are discovered when they are close to Earth, just because that is the time of their peak brightness. After their closest approach, they fade quickly as they move away from Earth. By observing them as soon as possible after their discovery, we are able to observe even small NEOs with small to medium sized telescopes. This observing strategy is called rapid response.

Also, we do not perform spectroscopy, which yields a fully resolved reflectance spectrum over a specific wavelength range, but spectrophotometry, which provides coarse spectral information by performing photometry in standardized filter bandpasses. Photometry is easier to obtain and more efficient than spectroscopy on smaller telescopes.

By combining spectrophotometry and rapid response observations, we are technically able to constrain the taxonomic class of every newly detected NEO.

We perform our observations in the optical and near infrared regimes, which are particularly indicative for asteroid taxonomy, using two different instruments and telescopes: WFCAM on UKIRT (3.8m, located on Mauna Kea, Hawai’i) and RATIR on the 1.5m  telescope at San Pedro Martir, Mexico. Target selection, observation, data reduction, and analysis are mostly automated for both telescopes, allowing for a high throughput with minimal human interaction. Target asteroids are selected based on their observability, bright NEOs are observed by RATIR, fainter ones by UKIRT.

First results from UKIRT are available and have been presented at the Division of Planetary Science meeting in Tucson, 2014 and the IAU General Assembly, 2015. The latest poster is available here. Our first paper has been published in AJ.