Buying Guide
The Telescope Simulator on Mobile — Complete Field Guide
This is the mobile-first guide to the AstroEquip Telescope Simulator — the same tool as the desktop version, but reorganised around the four-tab bottom drawer, touch gestures, and the way you actually use the simulator at the imaging site. Every section maps to a panel you can swipe up. On a desktop or laptop? See the desktop guide — the toolbar layout is very different.
In this guide
- The mobile layout — sky, header, tab bar, drawer
- Gestures — pan, zoom, rotate, identify
- Object tab — find a target
- Gear tab — autofill your gear
- Gear tab — manual + custom entries
- Imaging trains & the node designer (Combine vs Compare)
- Sky tab — filter, rotation, exposure
- Calc tab — sub-exposure & SNR calculator
- Calc tab → Stats segment — sampling, trailing, light budget
- The mobile header — Save, Settings, Share, Info
- Settings ⚙ — Bortle, Location & Time, surveys
- The HUDs & the ⓘ object popup
- Save setups, snapshots & share links
- Picks and the Gear Finder button
- At the imaging site — three field workflows
- Test a gear upgrade from your phone
- Tips, gestures & gotchas
1. The Mobile Layout — Sky, Header, Tab Bar, Drawer
The mobile UI has four persistent regions:
- Sky viewport — the dark area in the middle. Always full-bleed when the drawer is closed.
- Mobile header (top, slim bar) — small icon buttons: Save snapshot (📷), Settings ⚙, Share ↗, Info ℹ.
- Tab bar (bottom, four icons) — tap any tab to slide up its panel.
- Drawer — slides up from the bottom when you tap a tab. Holds the four panels.
The four bottom tabs:
| Tab | Opens panel for… |
|---|---|
| Object | Searching, popular target chips, navigating to coordinates. |
| Gear | Telescope / camera / mount — autofill, manual, or custom. |
| Sky | Filter mode, projection, rotation, exposure brightness. |
| Calc | Sub-exposure / SNR calculator + stats readouts (segmented switcher). |
Tap a tab to slide its panel up. Tap the same tab again — or drag the drawer down by its handle — to slide it back down. The sky stays live behind the drawer, so you can pan a target into the part of the sky still visible above an open drawer.
Drag the drawer to resize
The small handle at the top of the drawer is draggable. Drag down to make the drawer smaller (more sky visible), drag up to make it larger (more panel visible). The drawer remembers its last height across opens.
2. Gestures — Pan, Zoom, Rotate, Identify
| Gesture | Action |
|---|---|
| One-finger drag | Pan the sky. Framing rectangle stays centred. |
| Two-finger pinch | Zoom the sky in/out. Smooth across the full survey resolution range. |
| Two-finger twist | Rotate. Mode is set in the Sky tab — FOV rotates the frame, POV rotates frame + sky together, FOV+POV rotates only the sky. |
| Tap an object | Pulls up a name label. |
| Tap ⓘ in the HUD | Opens the object info popup — altitude, transit, rise/set, best months. |
| Long-press the sky | "What is this?" popup — names the nearest catalogued object and offers a centre-on button. |
3. Object Tab — Find a Target
Tap the Object tab (left-most in the bottom bar). The panel slides up with:
- Search box at the top — type any object name (M31, NGC 7000, IC 1396).
- Catalog dropdown just below — filter the autocomplete to All / Messier / NGC / IC / Barnard.
- Popular targets grid — tap a card to jump straight to M31, M42, Pleiades, M51, M81, North America Nebula, IC 1396, or M16.
Once you've picked a target the drawer can stay open or you can close it (tap the active tab again, or drag the handle down). Either way the framing rectangle and the HUD update live.
4. Gear Tab — Autofill Your Gear
Tap the Gear tab. The panel that slides up has, top to bottom: an imaging-goal selector, three gear cards (telescope, camera, mount), and below them a Picks chip + a Compare row.
Imaging goal — set this first
The drop-down at the top picks what you're shooting tonight: Deep-sky (general), Galaxies, Nebulae & wide-field, Planetary & lunar, Solar, or Visual / casual. It drives filter recommendations and lets the simulator score your build for warnings — oversampled for galaxies, fast f/<4 paired with the wrong corrector, alt-az on a long-FL goal that needs autoguiding, etc. Warnings appear in the Stats segment of the Calc tab. Without a goal selected, the simulator still frames but can't warn you about the kit.
Type your model
Type the actual product name into the input — e.g. "Esprit 100", "ASI2600", "AM5", "RedCat 51". As you type, the dropdown shows matching products from the AstroEquip catalogue. Tap a result.
The simulator fills in:
- Telescope: focal length, aperture, focal ratio, optical design, weight.
- Camera: sensor format, pixel size, sensor dimensions, camera type (OSC / mono / DSLR).
- Mount: mount type (EQ GoTo / Star Tracker / Alt-Az), payload, weight.
The framing rectangle, the live-stats summary, and the Calc tab all update instantly. Switch by tapping SWAP on the populated card. Remove with the × button to return to the autofill input.
5. Gear Tab — Manual + Custom Entries
Scroll down inside the Gear panel. Below the gear cards you'll find a row of manual inputs you can use without the catalogue:
| Input | What it sets |
|---|---|
| Focal length | Focal length in mm. Printed on every scope. |
| Sensor | Sensor format — Full Frame, APS-C, MFT, 1", 2/3". |
| Pixel | Pixel pitch in µm. Drives the image-sampling number. |
| Mount | EQ GoTo / Star Tracker / Alt-Az. |
Autofill and manual entry can be mixed — autofill a telescope, then override the focal length to simulate a reducer or extender. Nothing else breaks.
Add custom gear
If your specific model isn't in the catalogue and you want it to appear in the dropdown next time, tap the small + Add custom gear link below the autofill input. The form takes:
- Telescope: name, focal length, aperture, optical design, weight.
- Camera: name, sensor W × H, pixel size, camera type (OSC / Mono / DSLR / Mirrorless).
- Mount: name, mount type, payload, weight.
Custom entries are saved to your phone's local storage only — they're not synced or shared. They reappear in the autofill dropdown next time you type. Found gear we should catalogue for everyone? Send a feedback note via the Tutorial-button row in the open drawer footer.
6. Imaging Trains & the Node Designer
The simulator isn't limited to one rig. You can build several imaging trains and plan a dual-rig night from your phone: a wide refractor and a long scope side by side, or two cameras chasing two targets in parallel. Each train is a full rig with its own telescope, camera, accessories, focal length, and sensor.
Opening the node designer on a phone
Tap ⧉ Rig nodes to open the node designer. It slots between the header and the tab bar and draws each train as a chain of nodes: telescope to camera, with accessories in between. The touch targets are finger-sized and the toolbar runs across the top.
Add a train
Tap + New train in the node toolbar. It starts blank; fill it from the Gear tab like the first one.
Select a train
Tap any node on a train. The Gear tab, the Calc tab, the Stats segment, and that train's framing rectangle all switch to it, so edits from the Gear tab now change that train only.
Rename or remove
Double-tap a node to rename its train. Tap the × on a node to remove it. Each train's row in the Trains list can also be saved as its own setup.
By default the sky re-centres and rotates to the selected train's framing. To keep the sky fixed and move only that train's FOV outline, flip Settings ⚙ → Selecting a train to "Sky stays put."
Combine vs Compare
Tap the sky background, or the Combine | Compare control in the node toolbar, to deselect every train and open the all-trains view. The segmented control (in the node toolbar, and at the top of the Stats segment) switches how the pair is read:
| Mode | What it shows |
|---|---|
| Combine | Both trains as one system on the same target: combined integration time, the √SNR gain from stacking, total light-gathering versus your largest scope, and cameras in parallel. |
| Compare | Each train side by side, no merging: focal length, f-ratio, field of view, and sampling. |
Combine answers "what do these two rigs achieve together on one target?" Compare answers "how do my two rigs stack up?" Tap the small ⓘ button beside the control for the same explanation, with a link to the full guide.
Trains on the Calc tab
With two or more trains, the Calc tab adds a Your trains panel: each train's sampling, f-ratio, and the time it needs to reach the same target SNR, plus the combined payoff either way (one target with all trains, or each train on its own target in parallel). The single-train fields at the top of Calc follow whichever train is selected.
7. Sky Tab — Filter, Rotation, Exposure
Tap the Sky tab. The panel has:
- Filter mode — Broadband / Hα / OIII / SHO / HOO / 2MASS / PanSTARRS. When you pick Hα, OIII, SHO, or HOO, a small band-intensity bar pops up at the top of the screen so you can tune the channel weightings.
- Projection — leave on TAN unless you're shooting through a fisheye or hyperbolic corrector (RASA / Hyperstar).
- Rotation — number input plus three mode buttons: FOV (rotate the framing rectangle only), POV (rotate frame + sky together — frame stays anchored to the same stars), FOV+POV (rotate only the sky — frame stays pixel-locked on screen). Tap reset (↻) to return to 0° = celestial north up.
- Exp — exposure slider for image brightness. Cosmetic only — doesn't affect any calculations.
8. Calc Tab — Sub-Exposure & SNR Calculator
Tap the Calc tab (right-most in the bottom bar). The panel has a segmented switcher at the top:
- Calc — the sub-exposure / SNR calculator (this section).
- Stats — the readouts panel (next section).
Calc answers the most common planning question: how long should each sub be, and how many do I need?
The four camera preset buttons
One-tap presets for sensible read-noise + dark-current values:
Modern cooled CMOS
ASI2600MC, ASI2600MM, ASI533MC/MM, ASI6200, QHY268. RN ≈ 2e⁻, dark ≈ 0.001e⁻/s at −10°C.
Older cooled CCDs
QSI, SBIG, Atik, older Moravian. RN ≈ 3.5e⁻, dark ≈ 0.002e⁻/s.
Uncooled CMOS, mirrorless
Sony α7, Canon EOS R, ASIair OSC bodies without cooling. RN ≈ 5e⁻, dark ≈ 0.01e⁻/s.
Older / modified DSLRs
Canon EOS Ra, modded Canon 600D. RN ≈ 8e⁻, dark ≈ 0.05e⁻/s.
Tap a preset and the read-noise + dark-current fields autofill. You can edit either by hand if you know your camera's specific values from the manufacturer spec sheet.
Sub length + number of subs
Type your planned individual exposure time (in seconds) and how many subs you intend to capture. Typical values for deep sky: 30–300s subs, 30–200 total.
Narrowband & target SNR
Below the basic inputs:
- Hα / OIII / SII (÷20 sky) checkbox — when on, divides the sky-background contribution by ~20×. Reflects how much light a 6nm narrowband filter rejects.
- Target class dropdown — Faint nebula / dim galaxy · Typical galaxy / DSO · Bright nebula · Very bright. Sets assumed target signal strength.
- Desired stack SNR — 20 (visible), 50 (clean), 100 (magazine quality).
What's pulled from your simulator setup
- Bortle scale — from Settings ⚙.
- Pixel scale — focal length × pixel size.
- Sky background brightness — derived from Bortle + pixel scale.
The result cards
| Result | What it tells you |
|---|---|
| Required integration | Total integration time to hit your target SNR. Fix the quality bar, get the minutes / hours. |
| Predicted SNR | The inverse: given your planned sub length × number of subs, what stack SNR will you actually reach? Fix the session length, get the quality bar. |
| Optimal sub | Sub length where sky noise dominates read noise by ~10×. Below = read-noise-limited; above = diminishing returns. |
| Total time | Sub length × number of subs. Real sessions lose 15–25% to dithers, flips, focus — round up. |
| Stack read noise | Effective read noise after stacking (R / √n). Halving it requires 4× more subs. |
| SNR gain | SNR improvement vs. a single sub. 25 → 100 subs only doubles SNR. |
Use Required integration for multi-night planning ("how many nights to clean galaxy detail?") and Predicted SNR when the session length is fixed by clouds or work the next morning ("three hours tonight — what's the realistic quality?"). A Read-noise-limited hint surfaces below either readout when your subs are short enough that more subs won't help much — longer subs would.
Noise breakdown bar
The horizontal bar below the results shows, per sub, what fraction of total noise comes from each source. Use it to diagnose:
- Read-noise-dominated: subs too short — lengthen them.
- Sky-dominated: the regime you want. More subs help; longer subs help less.
- Dark-current significant: sensor too warm or subs longer than needed.
9. Calc Tab → Stats Segment — Sampling, Trailing, Light Budget
Tap Stats in the segmented switcher at the top of the Calc panel. The stats readouts panel slides in.
Image sampling (arcsec/pixel)
| Sampling | Verdict |
|---|---|
| < 1.0"/px | Over-sampled — consider a reducer. |
| 1.0–1.5"/px | Excellent — high-res deep sky in good seeing. |
| 1.5–2.5"/px | Good — matches typical seeing. |
| 2.5–4"/px | Coarse — fine for nebulae and wide-field. |
| > 4"/px | Very coarse — wide-field only. |
Star trailing limit
Maximum sub-exposure length before stars streak at your focal length and mount combination. EQ GoTo with guiding is effectively unlimited. A star tracker at 600mm is around 60s. Alt-Az at 1000mm is unusable for deep sky.
Field rotation (Alt-Az + Location on)
When you've picked an Alt-Az mount and Location is enabled in Settings ⚙, Stats adds a Field rotation row. It shows the current rotation rate for your target's altitude / azimuth at your location, plus a suggested maximum unguided sub before rotation visibly smears stars at the frame corners.
Light budget
Total integration time needed for a clean image given your target, Bortle value, and filter choice. Galaxies under Bortle 6 with no filter: 3–5h. Same galaxy at Bortle 3: 1–2h. Narrowband targets: 3–5h per channel even under good skies.
10. The Mobile Header — Save, Settings, Share, Info
The slim bar at the top of the screen holds the meta actions. Icon-only on mobile to save space — tap and hold for tooltips on most systems.
| Icon | What it does |
|---|---|
| 📷 Save | Opens the snapshot modal — choose 1× / 2× / 3× resolution, PNG / JPG format, watermark + overlay toggles. Saves to your camera roll. |
| ⚙ Settings | Opens View settings — filter, projection, pixel, Bortle, Location & Time. The next section. |
| ↗ Share | Copies a link that re-creates the exact view. |
| ℹ Info | Shows the current setup summary in a popup. |
The Tutorial replay button isn't on the header — it's at the bottom of any open drawer (in the "Sky data: Aladin Lite / CDS Strasbourg" credit row). Tap it from any open panel.
11. Settings ⚙ — Bortle, Location & Time, Surveys
Tap the gear icon in the top header. The View settings modal opens with two sections.
Imaging parameters
- Filter — same options as the Sky tab's filter dropdown; either place sets it.
- Projection — TAN default. Switch only for fisheye or RASA / Hyperstar.
- Pixel — pixel pitch in µm. Mirrored to / from the Gear tab.
- Bortle — sky brightness 2 (rural-dark) → 8 (city). Look it up at lightpollutionmap.info.
Location & Time
The most important block on mobile, because phones know where they are.
- Where — preset city dropdown, or tap Use my location to read GPS (one-time browser prompt; never sent to AstroEquip).
- Lat / Lon — type directly if you'd rather not give GPS access.
- When — Live (now), Tonight (next astronomical-dark midpoint), Pick… (specific date/time).
- Horizon — degrees of obstruction from trees / buildings.
- Enabled — toggle the whole location-aware behaviour on or off.
What changes once Location is on:
- The ⓘ object popup adds altitude, transit, rise/set, and best months at your latitude.
- HUD warnings flag Sun-up, twilight, and bright Moon near the target.
- Stats adds a Field-rotation row when you've picked an Alt-Az mount.
- The compass overlay labels the celestial pole's altitude.
Sky survey picker
The Sky tab also exposes the survey selector (mirrored from the desktop toolbar's Survey button). Tap it to switch between DSS2 Color, DSS2 Red/Blue, 2MASS (infrared), Mellinger (all-sky), or PanSTARRS (deep optical, north only). DSS2 Color is the default — most familiar look.
12. The HUDs & the ⓘ Object Popup
Two information overlays float over the sky viewport:
Target HUD (top-left)
Current target name + field of view (W × H).
- ◎ Field toggle — switches between Field mode (auto-names whatever notable object is centred) and Locked mode (stays on what you last searched for). Useful during exploration.
- ⓘ — opens the object info popup.
The ⓘ object info popup
Pulls live Simbad data and overlays it with your location-aware visibility:
- Object name, identifier(s), and type.
- RA / Dec coordinates.
- Apparent magnitude and size (when catalogued).
- Tonight's altitude curve — rise / transit / set times at your location.
- Best months to image — when the target transits during astronomical dark at your latitude.
- Google search link for image references.
Nearby HUD (bottom-left)
Names notable deep-sky objects near your framing rectangle. Pops in only when there's something worth naming — useful for spotting "I'm one rotation away from also having M82 in this frame".
HUD warnings
With Location on, warning chips appear when:
- The target is below the horizon (or your custom horizon cutoff).
- The sky isn't astronomically dark.
- A bright Moon is angularly close to the target.
13. Save Setups, Snapshots & Share Links
Save a snapshot
Tap 📷 Save in the mobile header. The snapshot modal opens — pick resolution, format, watermark and overlays, then save. The PNG / JPG goes to your camera roll.
Share a link
Tap ↗ Share. Copies a URL that re-creates the exact view: target, gear, Bortle, rotation, filter mode, band intensities. Paste into a forum question, text it to your imaging partner, or save it to your notes.
Save the full setup to your account
Open the Gear tab and scroll to the bottom — there's a 💾 Save current setup button. Stores the full gear configuration plus the current target, rotation, filter mode, and narrowband mix to your AstroEquip account (signed in) or to local storage (signed out). Once signed in, saved setups sync across devices.
14. Picks and the Gear Finder button
The Picks comparator and the simulator are linked on mobile through three small touch points.
- Gear Finder button in the mobile header's left cluster (top-left). It opens the AstroEquip gear finder wizard in a new tab. The text label collapses to an icon on the narrowest screens; the destination is always the same. Use it when the simulator shows a compatibility issue you want to redesign around — for example, the framing is too tight at your focal length and you want to see what wider scopes the wizard would suggest for the camera you already have.
- Picks chip in the Gear tab opens a drawer with your saved Picks. Tap any pick to swap that telescope, camera, or filter into the current simulator setup. Same flow as the desktop sidebar flyout, just laid out as a vertical drawer over the Gear tab. The chip count updates live as you add to Picks elsewhere on the site.
- Compare row lives in the Gear tab on the mobile redesign (it used to sit in a separate tab on older builds). The buttons sit below the gear cards and let you switch between two saved setups without leaving the simulator.
The picks data syncs the same way as the desktop simulator. Signed-in to a Shopify customer account on any storefront and your Picks list is cross-device. Anonymous visitors get same-browser sync via localStorage. The chip count and drawer refresh automatically when the underlying list changes — including from another tab on the same phone, or from the storefront's My Picks page in a separate browser session.
15. At the Imaging Site — Three Field Workflows
Three concrete walkthroughs for using the simulator on your phone, in the dark, between setup steps.
Field workflow 1 — "I just finished polar alignment. What do I shoot?"
Open the simulator on your phone.
Sign in if you haven't — your saved setups will be there.
Load your gear (autofill or saved setup).
If you've saved a setup before, swipe up the Gear tab, scroll to Saved setups, tap the right one.
Tap Settings ⚙ and Use my location.
Set Bortle to your local value, time to Live. Now ⓘ tells you what's actually up, and the HUD will warn you about the Moon or twilight.
Enable Field mode on the HUD.
Close the drawer. One-finger pan around the part of the sky you can actually point at (most mounts can't image close to the horizon). The HUD will name candidate targets as you pass over them.
Tap ⓘ on each candidate.
Check the altitude curve and best months. Pick the one whose transit fits your session and that the Moon isn't shining on.
Open the Calc tab.
Tap Stats first — check the light budget vs. remaining session time. Then flip to Calc — your camera preset is likely already set from a prior session, so just check the optimal sub. If your real sub time matches it, you're sky-noise-limited; you're good.
Field workflow 2 — "Cloud just rolled in over my target. Reframe to another?"
Look up at the actual sky. Identify which patch is still clear.
Open the Object tab.
If the clear patch is near a known constellation, search for a bright reference (M31, M42, Vega, Capella).
Pan with Field mode on.
Find a target inside the clear patch. The HUD names it.
Tap ⓘ to confirm it's properly above your horizon.
Low targets have atmospheric refraction drift; if alt is under ~20° you'll have problems.
Check Calc → Stats for star trailing.
If your mount can handle the new target's altitude, you're good. Slew there and start integrating. You've lost maybe 10 minutes — much better than abandoning the session.
Field workflow 3 — "How long should I keep going?"
Open the Calc tab → Calc segment.
Set sub length to your actual current sub length, number of subs to how many you've already captured.
Total time → how much you've actually integrated so far.
Compare against Calc → Stats → light budget.
If light budget is 4h and you've integrated 2h, you're at 50% — clear benefit to keeping going. If you're at 80%+, the next hour is diminishing returns and you can pack up early if it's late.
Cross-check the noise breakdown.
If sky noise dominates the per-sub noise bar, you're collecting the right kind of data — more subs help. If read noise dominates, you should have been doing longer subs all along — note for next time.
16. Test a Gear Upgrade From Your Phone
Same simulator, same calculator. Phone-friendly upgrade decisions:
Upgrade test 1 — "Is a faster scope worth it?"
Open the Gear panel.
Note your current scope's focal length, focal ratio, and the live sampling number.
Tap SWAP on the telescope card.
Type the model you're considering — say "RASA 8" or "RedCat 71". Pick it from the dropdown.
Compare the framing on the same target.
Close the drawer and look at the sky. Pan to your usual target. The framing rectangle is now the new scope's — compare to what you saw before mentally.
Open Calc tab.
Run the calculator with the same camera preset. The new scope's faster f/ratio shortens the optimal sub. If your mount can't track that short → free win.
Upgrade test 2 — "ASI533 vs ASI2600 for my targets?"
Autofill ASI533MC. Frame your favourite target.
SWAP to ASI2600MC.
The framing rectangle changes — 1" sensor → APS-C is a big jump. Look at how many objects fit.
Open Calc tab for each.
Set the cooled-ASI preset. Run with your typical sub length. The lower read noise of the ASI2600 lets you shorten subs without becoming read-noise-limited.
Decide based on framing.
If the targets you care about overflow the ASI533, the ASI2600 is the upgrade. If they fit, the ASI533's smaller image circle is more forgiving on cheap optics.
Upgrade test 3 — "Tracker → EQ mount, is the jump real?"
SWAP the mount card from Star Tracker to EQ GoTo.
Open Calc → Stats. Star trailing limit jumps from 30–60s to effectively unlimited.
Open Calc → Calc.
Your existing sub length may be far below the optimal sub. With an EQ mount + guiding, you can finally hit optimal — much shorter total session time for the same SNR.
17. Tips, Gestures & Gotchas
Use Field mode while panning the sky.
The HUD names what you're looking at. Best way to discover targets near where you planned to image.
Two-finger twist works on the sky.
Rotate without opening the Sky tab. The mode (FOV / POV / FOV+POV) you've set decides what actually rotates.
Long-press the sky to identify an object.
The "What is this?" popup names the nearest catalogued object and gives you a centre-on button. Faster than typing a search.
Turn Location on once at the site.
Settings ⚙ → Use my location. Then the ⓘ popup, HUD warnings, and Stats field-rotation are all live for the rest of the session.
Calculator before you start integrating.
Running it in the dark for 30 seconds catches "subs too short" mistakes you'd otherwise only learn during processing the next day.
Save your setup at home, not in the field.
Once a setup is saved, signing in on your phone at the imaging site loads it instantly. Don't fumble with autofill in the cold.
Phone landscape mode helps a lot.
The drawer panels are designed for portrait, but landscape gives more sky-map real estate. Worth trying for the framing checks.
Pinch-zoom doesn't zoom the page chrome.
Locked intentionally so pinch is for sky zoom. For bigger UI text, use your browser's text-zoom menu.
Tutorial replay is in the open-drawer footer.
The Tutorial button at the bottom of any open panel replays the mobile tour. Useful refresher if you haven't opened the simulator in a while.
Open the simulator and plan tonight's session
The simulator is meant to be used on the device you have nearest at the imaging site — usually a phone. Sign in, load your saved setup, and decide what to shoot based on real numbers rather than guesses.
Open the Telescope Simulator →