Phase editor

A plan is a sequence of phases, each with its own capture recipe. The phase table and the editor for each phase are where you shape exactly what gets captured, and how fast.

The phase set

HelioMaker builds a phase for each stage of the eclipse. For a total eclipse the set runs, in order:

Phase	What it captures
Pre-eclipse	Before first contact; setup and baseline frames.
Partial ingress	C1 → the approach to totality; the shrinking crescent.
Thin crescent · C2	The last sliver before totality (optional; enabled by Include thin-crescent phase).
Diamond ring · C2	The diamond ring / Baily's beads at second contact.
Totality (or Annularity, or Central)	The central phase, showing the corona (total), the ring (annular) or the deepest crescent (partial).
Diamond ring · C3	The diamond ring returning at third contact.
Thin crescent · C3	The first sliver after totality (optional).
Partial egress	C3 → C4; the widening crescent.
Post-eclipse	After fourth contact.

The C3 phases mirror the C2 phases, so what you set going into totality is echoed coming out.

Annular and partial phase sets Annular and partial eclipses share a simpler five-phase set: Pre-eclipse, Partial ingress, the central phase, Partial egress and Post-eclipse. The thin crescent and diamond ring phases belong to a total eclipse only. The central phase is called Annularity on an annular plan and Central on a partial one — Central rather than Maximum on purpose, because it is a window minutes wide rather than the instant of maximum, and naming it after the instant made the two easy to confuse. To widen or narrow that window, select its row here and use Start before (s): and End after (s): below.

The phase table

The table lists every phase with its key numbers: Phase, Start, Duration, Gain, Exposure, Bracketing, Cycles, Interval, Shots, Coverage and Guiding. Two narrow columns flag whether the solar filter is off for the phase and whether a meridian crossing falls inside it. Select a row to edit that phase below.

Exposure and guiding plan table listing every eclipse phase with
start time, duration, gain, exposure, bracketing, cycles, interval, shots, coverage and guiding. — Select a row to inspect and edit that phase. The table provides an overview of the complete exposure and guiding plan.

Preview an HDR bracket and compare it with the recommendations

When you select a bracketed phase, expand Phase summary. It lists every exposure time in the HDR bracket and reports the full EV span, estimated time per set and total exposure time. This is the complete capture ladder that results from the selected base exposure, EV step and frame count.

The Tips: panel shows exposure guidance for the selected phase. HelioMaker scales these recommendations from the plan's measured full solar disk exposure and filter density, and accounts for the selected eclipse mode. Use the summary and Tips together while changing the recipe so you can see whether the resulting bracket covers the intended features and still fits the available phase time.

Expanded Totality Phase summary showing the complete HDR
exposure ladder, EV span, estimated time per set, editable imaging controls and phase specific Tips. — The expanded summary lists every exposure in the selected HDR bracket. Compare the ladder and its timing with the phase specific Tips while tuning the recipe.

Diamond ring lead and trail times The C2 and C3 diamond ring phases include Lead time (s): and Trail time (s):. They extend the selected phase before and after the corresponding contact, changing how much capture time is devoted to the diamond ring and Baily's beads. The values generated from Plan preferences... should normally be used unchanged. Experienced eclipse imagers can adjust them for a specific capture strategy, but should then review the timeline and rehearse the revised plan. In Diamond ring (Classical) mode, these phase boundaries also determine the filter change points.

Recipe for each phase

Exposure (ms): and Gain:: The exposure and gain for this phase. HelioMaker initially derives them from the measured filtered full solar disk exposure, the reference camera gain, the effective ND rating of the complete filter stack and Fred Espenak's eclipse exposure recommendations. Keeping the same gain for every phase is recommended; make a phase specific gain change only when physical camera testing supports it.
Bracketing: (EV/step × count): HDR bracketing specifies how many exposures occur in each cycle and how many EV separate them. Deeper brackets around C2/C3 capture the huge dynamic range of the inner corona and prominences.
Repeat (cycles):: How many times the recipe repeats within the phase. Max fills the phase's time slot with as many cycles as fit.
Interval (s):: The time from the start of one cycle to the start of the next, which defines the cadence rather than the gap between cycles. Max speed sets it to the fastest rate the camera can sustain. Every imaging interval in the plan is shown in seconds, in the phase table and in this editor, including the estimated time per cycle beside it. Guiding is the one exception: the guide exposure and guide interval below remain in milliseconds, which is the unit PHD2 itself uses.
Lead time (s): / Trail time (s):: For the diamond ring phases, how far before and after C2 or C3 the selected phase extends. The same controls adjust the applicable edge of a thin crescent phase. Plan preferences supplies the initial values; use these controls only for deliberate phase specific tuning.
Start before (s): / End after (s): (annular and partial central phase): The same pair of controls, renamed for what they do on the central phase of an annular or partial eclipse: how long before and after its anchor the phase runs. For annularity the anchor is the pair of inner contacts, so zero means the phase is exactly C2 to C3 and larger values extend it either side. For a partial eclipse the anchor is maximum itself, and since there are no inner contacts these two values are what give the phase its length. Partial ingress and egress take whatever is left on each side.
Overrun:: What to do if a cycle is still running when the phase ends: Cancel & switch or Finish, then switch.

Phase Imaging controls for exposure, gain, HDR bracketing, repeat
cycles, overrun policy, capture interval and lead time. — The Imaging panel changes with the selected phase. This example includes Lead time; a diamond ring phase provides both Lead time and Trail time for experienced timing adjustments.

Tune a measured plan, not a guessed one First measure the filtered full solar disk with the actual eclipse rig and enter the exposure, gain and effective total ND rating in Plan preferences. Let HelioMaker derive the phase set, then use this editor to tune it. The phase editor locks when automated imaging starts, so exposure and gain changes must be completed, approved and rehearsed before the run.

Coverage & interval Interval is the spacing from the start of one cycle to the start of the next. Coverage reflects how well the phase samples the changing eclipse. For the partials, the Uniform coverage option (in Plan preferences) spaces shots by how much the crescent has changed rather than by a fixed clock interval, so you do not oversample the slow parts or undersample the fast ones.

How many cycles will actually fit? The C2/C3 bracket cadence and the number of cycles that fit in totality depend on your camera's measured overhead and the capture mode. In Live view mode each short bracket rung is recorded as several frames to stay honest, so totality writes many runs of short frames; Still mode captures exact exposures and usually fits more complete sets. Run the System benchmark test so the minimum intervals and cycle counts here are realistic, and see Capture mode: Still versus Live.

When you ask for more cycles than fit Set Repeat (cycles) higher than the phase's time slot allows and the table shows both numbers, as 31 (50)* — the scheduled count first, what you asked for in brackets. The plan description says the same thing in words: 50 requested; 31 fit. HelioMaker does not silently reduce the request, and it does not pretend the extra cycles will happen.

Shots and recorded frames are different numbers Shots counts what you asked the camera for: cycles multiplied by the exposures in the bracket. A three-exposure bracket repeated 45 times is 135 shots. In Live view a short rung is recorded as a run of several frames, so the number of files on the disk is larger — that figure is the recorded frame count, and it is used for disk-space estimates rather than presented as your shot total.

Per phase guiding within the plan limits

PHD2 guiding: in Plan preferences establishes the overall guiding policy and populates the phase plan. The Guide this phase: option then lets you enable or disable guiding for an individual phase where the selected physical setup permits it. The phase panel also provides Exposure (ms): and Interval (ms): for the guide camera. A per phase choice cannot override a guiding restriction imposed by the contact window or the selected camera setup.

The plan-wide Guide interval (ms): is copied to every phase when it changes. Its allowed range is 500 to 6000 ms, with 2000 to 4000 ms recommended as a starting range. Make any phase-specific interval adjustment here after applying Plan preferences; keep the interval longer than the guide exposure.

Per phase Guiding controls for guide exposure, guide interval and
the Guide this phase option. — Use the phase controls to refine the guiding policy supplied by Plan preferences. Controls are unavailable where the current setup requires guiding to pause.

The C2 and C3 contact windows always pause HelioMaker disables guiding through the thin crescent and diamond ring phases around C2 and C3 in both physical setups. Near a contact, the detected target changes from a thinning crescent to beads and then the corona. Continuing to guide can lock onto the wrong feature and move the mount away from the intended position. The mount continues tracking during this brief pause, which together with totality normally lasts only a few minutes. As the photospheric limb grows bright enough for reliable detection after C3, HelioMaker resumes guiding and returns the Sun to its original locked position.

Guiding inside totality requires a separate guide scope A Shared camera cannot guide during totality because the same camera is capturing the eclipse. With a Physical guiding camera, guiding inside totality is available only when PHD2 guiding: is set to Partial phases and totality in Plan preferences and guiding remains enabled for the totality phase. This requires the separate guide scope to work without its solar filter during totality. Review Safety and eclipse modes and rehearse both filter procedures.

Applying plan changes

When you apply changed Plan preferences, HelioMaker asks before deriving the affected phase settings again. Within the phase editor, use Max to fill the available time with cycles and Max speed to choose the fastest sustainable interval. Then adjust the phases you care about most, usually the C2/C3 group.