You can obtain DASCH data through several different channels: daschlab, the DASCH web APIs, or Starglass. Whatever method you use, you are urged to join the DASCH Astrophysics email list to ensure that you can join in discussions relating to DASCH data analysis.
The DR7 documentation describes the official DASCH data products. See also the DR7 summary of known issues.
If you make use of DASCH data in scholarly work, you should properly cite and acknowledge DASCH.
daschlab
For DR7, the DASCH team has introduced a new system for accessing and analyzing DASCH data: a Python toolkit called daschlab. Cloud-based notebooks allow you to perform basic data retrievals and analysis with minimal need to understand Python and no required software installation. See the DR7: Getting Started section to, well, get started.
daschlab is now the recommended framework for retrieval and analysis of DASCH astronomical data.
Web APIs
Underlying daschlab are an assortment of web API endpoints that can be used to retrieve DR7 data. In many cases, daschlab is really only a thin layer on top of these APIs, which use a standard JSON-oriented, RESTful paradigm. The DR7 Web APIs page documents them and provides links to additional resources.
Starglass
The Starglass website provides a user interface and a programmatic API allowing access to DASCH plate-level data products and queries. While Starglass does not provide access to DASCH lightcurve data, it does provide plate photographs and full-plate FITS “mosaics”. If you sign up for a Starglass user account, you can obtain an API key allowing you to make requests, including mosaic retrievals, with much higher rate limits than are allowed for anonymous clients. Visit the Starglass site to see what it holds.
The web APIs that support Starglass are implemented in the same framework as the ones that support DASCH DR7 scientific data access. In addition to the resources linked above, you may wish to read the Starglass API docs to learn how to fetch data from Starglass systematically.
“Cannon” Data Portal
The original DASCH website was the “Cannon”
data portal at dasch.rc.fas.harvard.edu. Due to a need to retire old and
insecure webservers, this site is no longer able to provide data access.
Data Access Restrictions
Historically, only subsets of DASCH data were accessible to the general public. As of 2024, all DASCH data access restrictions have been lifted.