# Assessment Instructions: Problem Set 05 — Parker Solar Probe and Remote-Sensing Geometry

## Inputs to Inspect
Student submission, this problem set, the solution key, the corresponding lecture slides/notes, and the referenced dataset(s) under `materials/ASTR370/data/`.

## Grading Standard
Award credit for correct method and units first, then for the specific numeric result. A student who shows correct reasoning with a small arithmetic slip should receive most of the available credit; a student with a correct-looking number but no visible derivation steps should not. Because this is a 300-level quantitative solar physics and space weather course, full marks require a genuine derivation wherever the problem set asks for one, and a genuinely reasoned (not merely asserted) interpretation wherever the problem asks for scientific judgment (e.g., honestly characterizing an order-of-magnitude estimate's uncertainty, or a historical reconstruction's disclosed range).

## Problem-Level Criteria
- Problem 1: verify the numerical Parker-wind solve at r=6 R_sun and the correct closer-is-slower conclusion.
- Problem 2: verify the explanation invokes the over-determined, many-mode nature of helioseismic inversion, not just restating that more data is better.
- Problem 3: verify both fractions are computed correctly and the decreasing-usable-fraction direction is stated correctly.
- Problem 4: verify correct ratio arithmetic using Earth's real orbital speed.

## Resubmission Policy
Students may resubmit within one week of receiving feedback. A resubmission must show a corrected derivation, not only a corrected final number, and should reference the specific feedback comment it addresses. Regrade to a maximum of 90% of the original point value unless the error was a grading mistake.

## Common Errors to Flag
- Assuming wind speed increases monotonically as one gets arbitrarily close to the Sun without regard to the critical point's location.
- Reversing the direction of the occulting-disk-size sensitivity (claiming a larger disk increases the usable fraction).
- Confusing PSP's orbital speed with a solar-wind speed measurement in the final ratio.