Results Highlights:
Circular flares                                                Black-light flares in He I D3
     
Moreton waves and filament oscillations

From 1969 to 1995, Big Bear Solar Observatory (BBSO) recorded all observations on 35 mm films before its post-1995 switch to digital imaging. The film data include full-disk Hα observations from its 8 inch telescope and high-resolution observations in Hα and He I D3 from its 10 and 26 inch telescopes. The cadence of data ranges from about 10 s to 1 minute. BBSO has an excellent clear sky fraction. These film data covering two and half solar cycles span the operational service period of several space missions (e.g., SMM, CGRO, and Yohkoh). Public access to the film data was difficult and their scientific capability has far from been fully explored.

Supported by NSF, this project aims to digitize BBSO films using specialized commercial digitizing equipment and archive them in the public domain. The BBSO data to be digitized includes full-disk and selected high-resolution H-alpha and He I images. The entire set of film data will be converted to create a synoptic data base. With a supplement funding from NASA, we will also digitize full-disk Hα images from 1963 to 1997 obtained by National Solar Observatory (NSO) at Sacramento Peak, which are complementary to BBSO data in coverage and with its off-band observations. The observed solar flares and filament eruptions will be automatically detected and cataloged using artificial intelligence methods that have been developed and implemented at the Space Weather Research Laboratory of the New Jersey Institute of Technology.

The digitized solar images may not be suitable for accurate photometric analysis due to the nonlinear intensity response of films. Nevertheless, morphological study on solar features (e.g., filament activities and flares) can be carried out after applying standard image processing techniques. The rich film data base contains many unique events that challenge our understanding. Importantly, the long-term coverage and high quality of the BBSO/NSO film data plus the digital data from our Global Halpha Network will have very broad applications for statistical analyses, such as the cycle variation of solar activities. The study of a large number of archived events has promise to improve the forecasting of future solar eruptive events, and thus assist operational space weather prediction.

Current project progress: We have finished digitizing all the full-disk BBSO and NSO Hα films, and about 70% of high-resolution BBSO films. In total, over 40 million images have been archived. Quick-look movies and images are now released via a searchable data catalog, based on which users can make data requests. We have also obtained some significant results using the film data. We welcome your suggestions/comments, and please also contact us if films of your interested time period have not been digitized.

A sample digitized BBSO full-disk image
> Full image 2048 x 1600

A sample digitized NSO full-disk image
> Full image 2048 x 1600

A sample digitized BBSO high-res image
> Full image 2048 x 1600


Acknowledgement:
Release of the BBSO film data in digital form is dedicated to Professor Harold Zirin, the founder of BBSO, who passed away on 2012 January 3. We thank BBSO staffs for tremendous efforts in observations and film developing. This material is based upon work supported by the National Science Foundation under grant AGS 0849453. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
This project is also supported by NASA grant NNX11AC05G.