In attempting to develop code using astrometric data in DP0.2, I have looked over LDM-153 which is the “LSST Database Baseline Schema” from 2019. There are some fields, such as “parallax” which were meant to be in the Object and Source tables but are not there. I understand that DP0.2 was not meant to serve all science interests, but I am curious to know if these fields that were originally expected will appear in DP1 or DP2?
Hi @sdcorle1 , thank you for your question. Proper motions and parallaxes were not included in the DC2 simulations (on which DP0.2 is based) due to limitations in the pipelines at the time the data was processed (see the comments in this related post: Milky Way astrometry in DP0). These fields are planned for future data releases. However, for the particular case of DP1 and DP2, they will probably not be included, as it is unlikely that DP1 or DP2 will have a long enough baseline to accurately distinguish proper motion and parallax for all objects.
For DR1, we aim to report these values for bright, isolated stars used for calibration. Expanding this to the entire Object catalog in later data releases is a goal, but it involves advanced methods that need to be tested and validated first.
Regarding DP0.2, there is a post by @babel that seeks to create a parallax model with external data which might be helpful in this case: Cross-matching SDSS and Gaia Data.
Thanks, your thorough and thoughtful reply is very much appreciated. I’ll give the link a try for a short-term alternative.
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Hi @sdcorle1 , just wanted to follow up to see if you have any further questions on the parallax model/measurements in DP0.2. Thanks again for the nice questions.
No, thanks, I understand the situation better after the RCW last week.
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