| Series | Subseries | Arrangement | # of folders | Total size |
| Administrative records | Rita A. Spenser | Chronological | 23 | 2 linear feet |
| Financial records | Chronological | 34 | ||
| Union University | Chronological | 2 | ||
| Observatory procedures | Chronological | 2 | ||
| Boss laboratory | Chronological | 3 | ||
| Activity | Chronological | 1 | ||
| CETA | Chronological | 10 | ||
| Insurance | Chronological | 4 | ||
| Miscellaneous | Chronological | 1 | ||
| Curtis L. Hemenway |
Correspondence | Reverse chronological | 16 | 3.5 linear feet |
| Board of Trustees | Chronological | 2 | ||
| SUNY/A-Union-RPI | Chronological | 10 | ||
| [assorted] | Chronological | 49 | ||
| COSPAR | Reverse chronological | 26 | ||
| NYAC | Chronological | 4 | ||
| IAU | Chronological | 2 | ||
| [Papers & miscellaneous] | 21 | |||
| Douglas S. Hallgren |
Financial records | Chronological by category | 19 | 1.25 linear feet |
| Correspondence | Chronological | 8 | ||
| Contract records | 10 | |||
| Buildings & apparatus | 15 | |||
| Other Dudley Staff |
[Various individuals] | Chronological | 19 | .5 linear feet |
| Buildings & apparatus | Buildings & real estate | Chronological | 15 | .75 linear feet |
| Radio telescope | 16 | |||
| Apparatus | Chronological | 20 | ||
| Grants & Contracts |
Proposals (rejected) | Chronological | 99 | 16.5 linear feet |
| Forms, procedures, etc. | Chronological | 13 | ||
| Correspondence | Reverse chronological | 5 | ||
| Vouchers | Chronological | 1 | ||
| Grants | Chronological by grant (administrative records precede research data) |
473 | ||
| Contracts | Chronological by contract (administrative records precede research data) |
246 | ||
| NASA tape transcripts | Chronological | 43 | ||
| Library | Correspondence | Chronological | 27 | 5.5 linear feet |
| [assorted administrative] | Alphabetical | 62 | ||
| Subject files | Alphabetical | 91 | ||
| Friends of the Observatory |
Records | Chronological | 31 | .5 ln. ft. |
| Skywatch Line |
Scripts | Chronological | 9 | .5 ln. ft. |
| Henry Hudson Planetarium |
Records | Chronological | 15 | .5 ln. ft. |
| Photo Lab |
Photo files | Roughly by contract/activity | 680 | 20 linear feet |
| Glass Plates | by size | 15 boxes | 5 linear feet | |
| Lantern slides | Unsorted | 9 boxes | ||
| Negatives | Unsorted | 1 box | ||
| Motion picture film | Unsorted | 5 boxes | ||
| Prints | Unsorted | 3 boxes | ||
| Slides | Roughly by Subject | 4 notebooks |
