brickbots · brickbots · Jun 7, 2026 · Jun 7, 2026
diff --git a/docs/source/build_guide.rst b/docs/source/build_guide.rst
diff --git a/docs/source/catalogs.rst b/docs/source/catalogs.rst
@@ -2,24 +2,22 @@
 PiFinder™ Catalogs
 ===================
 
-The PiFinder comes with a number of astronomical catalogs which can be searched and filtered.
-Each has a short catalog code displayed on the PiFinder UI.  You can select which catalogs
-are active via the :ref:`Filters<user_guide:filters>`
-menu.
+The PiFinder ships with several astronomical catalogs you can search and filter.
+Each carries a short catalog code shown on the UI. Choose which catalogs are
+active in the :ref:`Filters<user_guide:filters>` menu.
 
-A few of these catalogs — the Washington Double Star catalog especially — hold far too many
-entries to scroll through.  For those, use **Name Search** to jump straight to an object by
-its designation, or sort a list by **Nearest** to surface the objects closest to where your
-scope is currently pointed.
+A few catalogs — the Washington Double Star catalog especially — hold far too many
+entries to scroll. For those, use **Name Search** to jump to an object by its
+designation, or sort by **Nearest** to surface the objects closest to where your
+scope is pointed.
 
 Abl
 ----
-The Abell Catalog of Planetary Nebulae (1966 by George O. Abell) contains 79 entries confirmed to be planetary nebulae.
+The Abell Catalog of Planetary Nebulae (George O. Abell, 1966): 79 confirmed planetary nebulae.
 
 Arp
 ----
-Atlas of Peculiar Galaxies    (Arp 1966)
-Select galaxies with interest morphology.  See `Wikipedia - Atlas of Peculiar Galaxies <https://en.wikipedia.org/wiki/Atlas_of_Peculiar_Galaxies>`_
+Atlas of Peculiar Galaxies (Arp 1966). Galaxies with unusual morphology. See `Wikipedia - Atlas of Peculiar Galaxies <https://en.wikipedia.org/wiki/Atlas_of_Peculiar_Galaxies>`_
 
 B
 ----
@@ -31,20 +29,19 @@ Caldwell catalog
 
 Col
 ----------
-The Collinder catalogue has 471 open clusters compiled by Swedish astronomer Per Collinder.
+471 open clusters compiled by Swedish astronomer Per Collinder.
 
 EGC
 ----
-Catalog of Extra-Galactic Globular Clusters. This catalog features globulars associated with nearby galaxies and are visible through modest amateur telescopes, mostly in Andromeda.
+Catalog of Extra-Galactic Globular Clusters: globulars associated with nearby galaxies, mostly in Andromeda, visible through modest amateur telescopes.
 
 H
 ----------
-The Herschel 400 catalogue is a subset of William Herschel's original Catalogue of Nebulae and Clusters of Stars, selected in response to a letter in Sky and Telescope.
+A subset of William Herschel's original Catalogue of Nebulae and Clusters of Stars, selected in response to a letter in Sky and Telescope.
 
 Harris
 -------
-Globular Clusters in the Milky Way (Harris, 1997)
-This catalog compiled was by William E. Harris and used by permisson.
+Globular Clusters in the Milky Way (Harris, 1997). Compiled by William E. Harris, used by permission.
 
 IC
 ----------
@@ -60,46 +57,44 @@ Messier catalog
 
 NGC
 ----------
-NGC 2000.0, The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J.L.E. Dreyer Sinnott, R.W.  (edited by)
+NGC 2000.0, The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J.L.E. Dreyer (edited by R.W. Sinnott).
 
 RDS
 ----
-the RASC Double Stars Observing Program.
-The 110 double star targets are visible from the northern hemisphere in many constellations.
+The RASC Double Stars Observing Program: 110 double-star targets visible from the northern hemisphere across many constellations.
 
 SaA
 ----------
 Saguaro Astronomy Club Asterisms Database Version 3.2
 
 SaM
 ----
-Saguaro Astronomy Club Double Star Database Version 4.0
-2162 double stars.
+Saguaro Astronomy Club Double Star Database Version 4.0: 2,162 double stars.
 
 SaR
 ----
 SAC Red Stars Database Version 2.0
 
 Sh2
 ----
-The Sharpless catalog is a list of 313 H II regions (emission nebulae) intended to be comprehensive north of declination −27°.
+313 H II regions (emission nebulae), comprehensive north of declination −27°.
 
 Str
 ----
-A catalog of named bright stars.  Especially useful for aligning GoTo scopes.
+Named bright stars. Especially useful for aligning GoTo scopes.
 
 Ta2
 ----------
-The TAAS 200 deep sky astronomical observing list designed for the intermediate observer, and includes the best 200 non Messier objects easily visible from central New Mexico, (objects north of declination -48).
+The TAAS 200 deep-sky observing list for the intermediate observer: the best 200 non-Messier objects easily visible from central New Mexico (north of declination −48°).
 
 TLK
 ----
 TLK's hand-picked list of interesting variable stars visible from the northern hemisphere.
 
 WDS
 ----
-The Washington Double Star Catalog — the PiFinder includes over 130,000 double and multiple
-star pairs from it.  Because the full list is far too long to scroll, find a pair with
-**Name Search** (type its WDS designation) or sort the list by **Nearest** to bring up the
-doubles closest to where your scope is pointing.
-For more information on WDS, please see: `https://www.astro.gsu.edu/wds/ <https://www.astro.gsu.edu/wds/>`_
+The PiFinder includes over 130,000 double and multiple star pairs from the
+Washington Double Star Catalog. The full list is far too long to scroll, so find
+a pair with **Name Search** (type its WDS designation) or sort by **Nearest** to
+bring up the doubles closest to where your scope is pointing.
+For more on WDS, see `https://www.astro.gsu.edu/wds/ <https://www.astro.gsu.edu/wds/>`_
diff --git a/docs/source/equipment.rst b/docs/source/equipment.rst
@@ -0,0 +1,155 @@
+Equipment
+=========
+
+The PiFinder can track the telescopes and eyepieces you observe with. Telling
+it about your gear is optional, but it unlocks several conveniences: it works
+out the magnification and true field of view for any telescope-and-eyepiece
+pairing, sizes and orients the survey images on the
+:ref:`user_guide:object details` screen to match the eyepiece view, and lets
+the push-to arrows follow the way your setup moves.
+
+You manage equipment from two places: the :ref:`user_guide:web interface` is
+where you add and edit telescopes and eyepieces, and the Equipment screen on the
+PiFinder is where you pick which ones are active for tonight's session.
+
+Telescopes and eyepieces
+------------------------
+
+A **telescope** records the optical details of one instrument: make and name,
+aperture, focal length, central obstruction, and mount type, plus a few display
+options covered below. Aperture and focal length drive the magnification and
+field-of-view calculations.
+
+An **eyepiece** records its focal length and apparent field of view, plus the
+field stop if you know it, which gives a more precise field-of-view figure.
+Store as many of each as you like and switch between them as the night goes on.
+
+Adding and editing your gear
+----------------------------
+
+Add telescopes and eyepieces through the :ref:`user_guide:web interface`.
+Connect to the PiFinder as described there, then open the Equipment page from
+the navigation menu. You'll find a list of telescopes and a list of eyepieces,
+each with buttons to add, edit, or remove an item.
+
+A new PiFinder starts with a generic 200mm Dobsonian and a small set of Plössl
+eyepieces so the calculations work out of the box. Edit or replace these with
+your own gear whenever you're ready.
+
+.. note::
+   The on-device Equipment menu builds its list of telescopes and eyepieces
+   when the PiFinder starts up. If you add new gear in the web interface while
+   the PiFinder is running, restart the PiFinder so the new items appear in the
+   on-device selection lists.
+
+Choosing your active telescope and eyepiece
+-------------------------------------------
+
+The PiFinder uses one **active** telescope and one **active** eyepiece at a time
+for its calculations and displays. Set these from either place:
+
+* **On the PiFinder**, open the :ref:`user_guide:tools` menu and select
+  Equipment. The Equipment screen shows the active telescope and eyepiece and,
+  when both are set, the resulting magnification and true field of view. Choose
+  "Telescope..." or "Eyepiece..." to pick from your stored gear.
+* **In the web interface**, use the Equipment page to mark a telescope or
+  eyepiece active.
+
+.. image:: images/equipment/equipment_screen_docs.png
+
+Choosing "Telescope..." or "Eyepiece..." opens a list of your stored gear, a
+check mark beside the active one. Use the **UP/DOWN** arrows to highlight an
+item and **RIGHT** to make it active.
+
+.. image:: images/equipment/select_telescope_docs.png
+   :width: 45%
+.. image:: images/equipment/select_eyepiece_docs.png
+   :width: 45%
+
+If nothing is selected, the PiFinder skips the magnification and field-of-view
+figures and shows the object image in its default orientation.
+
+Magnification and true field of view
+-------------------------------------
+
+With an active telescope and eyepiece set, the PiFinder shows two numbers on the
+Equipment screen:
+
+* **Magnification** is the telescope's focal length divided by the eyepiece's.
+  A 1000mm telescope with a 25mm eyepiece gives 40×.
+* **True field of view** (TFOV) is how much sky you see through that
+  combination, in degrees. Compare it against the push-to distance: when the
+  object is within half your true field of view of the centre, it's in the
+  eyepiece.
+
+The true field of view also sets the starting zoom of the survey image on the
+:ref:`user_guide:object details` screen, so the image frames roughly the same
+patch of sky your eyepiece shows. Zoom in and out from there with the **+** and
+**-** keys.
+
+Both figures appear on the object image too — field of view in the top-left
+corner, magnification in the top-right — so you always know the scale of what
+you're looking at.
+
+.. image:: images/equipment/object_image_fov_mag_docs.png
+
+Matching the object image to your eyepiece: flip and flop
+---------------------------------------------------------
+
+The survey images on the object details screen are oriented to match your
+eyepiece view, so you can compare them directly. Different telescopes flip the
+view in different ways, so two per-telescope options let you correct the
+orientation:
+
+* **Flip image (upside down)** mirrors the image top to bottom.
+* **Flop image (left right)** mirrors the image left to right.
+
+You don't need to reason about your optics. Point at a bright, recognisable
+object, compare the object image to your eyepiece view, and toggle the two
+options until they match:
+
+* If the image is **upside down** compared to the eyepiece, turn on **Flip**.
+* If the image is **mirrored** left-to-right, turn on **Flop**.
+* If it's both, turn on both.
+
+As a starting point for common setups:
+
+.. list-table::
+   :header-rows: 1
+   :width: 100%
+
+   * - Your telescope
+     - Flip
+     - Flop
+   * - Newtonian / Dobsonian
+     - off
+     - off
+   * - Refractor or SCT, straight through (no diagonal)
+     - off
+     - off
+   * - Refractor or SCT with a star diagonal
+     - one of the two — try Flop first
+     -
+   * - Refractor with a correct-image (erecting) diagonal
+     - on
+     - on
+
+A plain Newtonian or Dobsonian needs neither option, which is why both are off
+by default. A star diagonal produces a mirror image, so you'll need exactly one
+of Flip or Flop; which one depends on how the diagonal sits in the focuser, so
+pick whichever makes the image match.
+
+.. note::
+   Early PiFinder software shipped the default Dobsonian with Flop turned on by
+   mistake. If a Newtonian or Dobsonian image looks mirrored, open the telescope
+   in the Equipment page and turn Flop off.
+
+Reversing the push-to arrows
+----------------------------
+
+The same telescope settings include **Reverse Arrow A** and **Reverse Arrow B**,
+which flip the push-to arrows so they point the way your telescope actually
+moves. If nudging the scope in the direction an arrow points sends the target
+further away instead of closer, turn on the matching reverse option. The two
+arrows cover the two directions of movement, so enable A, B, or both until the
+arrows guide you the right way.
diff --git a/docs/source/images/equipment/equipment_screen_docs.png b/docs/source/images/equipment/equipment_screen_docs.png
diff --git a/docs/source/images/equipment/object_image_fov_mag_docs.png b/docs/source/images/equipment/object_image_fov_mag_docs.png
diff --git a/docs/source/images/equipment/select_eyepiece_docs.png b/docs/source/images/equipment/select_eyepiece_docs.png
diff --git a/docs/source/images/equipment/select_telescope_docs.png b/docs/source/images/equipment/select_telescope_docs.png
diff --git a/docs/source/images/sd_card/flat_open.jpeg b/docs/source/images/sd_card/flat_open.jpeg
diff --git a/docs/source/images/sd_card/sd_card_closup.jpg b/docs/source/images/sd_card/sd_card_closup.jpg
diff --git a/docs/source/images/sd_card/sd_card_closup_alt.jpeg b/docs/source/images/sd_card/sd_card_closup_alt.jpeg
diff --git a/docs/source/images/sd_card/sd_card_remove_screws.jpeg b/docs/source/images/sd_card/sd_card_remove_screws.jpeg
diff --git a/docs/source/images/user_guide/object_details_02.png b/docs/source/images/user_guide/object_details_02.png
diff --git a/docs/source/images/user_guide/quick_menu_00.png b/docs/source/images/user_guide/quick_menu_00.png
diff --git a/docs/source/images/user_guide/quick_menu_01.png b/docs/source/images/user_guide/quick_menu_01.png
diff --git a/docs/source/images/user_guide/quick_menu_02.png b/docs/source/images/user_guide/quick_menu_02.png
diff --git a/docs/source/index.rst b/docs/source/index.rst
@@ -63,11 +63,13 @@ Join the `PiFinder Discord server <https://discord.gg/Nk5fHcAtWD>`_ for support
    self
    quick_start
    user_guide
+   equipment
    troubleshooting
    catalogs
    build_guide
    v25_upgrade
    software
+   sd_card
    skysafari
    dev_guide
    dev_arch

diff --git a/docs/source/sd_card.rst b/docs/source/sd_card.rst
@@ -0,0 +1,108 @@
+Swapping the SD Card
+====================
+
+.. note::
+   This procedure is for v3 PiFinders.  The microSD card holds everything the
+   PiFinder runs — the operating system, the PiFinder software, your settings,
+   and the deep sky catalog images — so swapping it is how you recover from a
+   corrupt card or move to a fresh or larger one.
+
+The PiFinder boots from a microSD card tucked inside the case, in the slot
+between the Raspberry Pi and the power board.  This page covers getting at that
+card and swapping it.  To put software on the new card first, see
+:doc:`Software Setup <software>`.
+
+When you'd swap the card
+------------------------
+
+* The card has become corrupt and the PiFinder won't boot reliably (see
+  :doc:`troubleshooting`).
+* You'd rather re-image onto a spare card and keep your original as a backup.
+
+Image the new card before you open the case — the
+:ref:`software:prebuilt release image` is the quickest way, and it already
+includes the catalog images.
+
+Before you start
+----------------
+
+If the PiFinder is on, shut the PiFinder down cleanly first (Tools → Shutdown), wait for the screen and
+keypad to go dark, then switch off the power.  Pulling a card from a running unit
+can corrupt it.
+
+You'll need a small Phillips screwdriver.  The card sits in a friction slot —
+there's no spring to push it in or out, so you pull it straight out and push the
+new one straight in.
+
+Opening the case
+----------------
+
+On every v3 unit, start by removing the three screws on the right-hand side as
+you face the screen.
+
+.. image:: images/sd_card/sd_card_remove_screws.jpeg
+   :width: 70%
+
+How you reach the card from there depends on your configuration.  If you're not
+sure which one you have, the :ref:`build_guide:configurations overview` has
+photos of each.
+
+Right configuration
+~~~~~~~~~~~~~~~~~~~~~
+
+Simply lift off the separate cover held on by the three screws to expose the card.
+
+Left configuration
+~~~~~~~~~~~~~~~~~~~~
+
+For the left configuration, the three screws hold the camera assembly in place.  
+Gently tilt the camera assembly out of the way to reach the card. Be mindful of 
+the cable, but there should be plenty of slack.
+
+Flat configuration
+~~~~~~~~~~~~~~~~~~~
+
+The three screws hold one side of the flat cradle. Removing them allows enough flex to 
+gently pull the flat holder down to expose the card.  The image below shows this, but 
+was taken during assembly before the camera is installed.  There is no need to remove
+the camera to access the sd card.
+
+.. image:: images/sd_card/flat_open.jpeg
+   :width: 70%
+
+Swapping the card
+-----------------
+
+The card sits in the slot between the green Raspberry Pi board and the black
+power board.  The white camera ribbon cable runs nearby — move it gently aside
+if it's in the way, taking care not to crease or unseat it.
+
+.. image:: images/sd_card/sd_card_closup.jpg
+   :width: 47%
+.. image:: images/sd_card/sd_card_closup_alt.jpeg
+   :width: 47%
+
+Grip the card and pull it straight out, then push the replacement straight in
+until it's fully seated.  The card is easy to crack once it's part-way out, so
+support it as you work and don't flex it against the case.
+
+Reassemble and boot
+-------------------
+
+Reverse the steps: refit the cover or holder for your configuration, check that
+the camera ribbon is sitting flat and isn't pinched, and replace the three side
+screws — snug, not forced.
+
+Power the PiFinder on.  The first boot from a freshly imaged card takes longer
+than usual while it expands the filesystem to fill the card, so give it a couple
+of minutes.
+
+.. important::
+   After swapping the card you'll most likely need to set the **Camera Type**
+   again.  A freshly imaged card defaults to one sensor, and if it doesn't match
+   your unit the camera view will be blank.  Set it under Settings → Advanced → Camera Type
+   — the v3 sensors are ``imx462`` and ``imx296`` — then **fully power the
+   PiFinder off and on**, as a software restart alone won't apply the change.
+   See :ref:`troubleshooting:the camera view is blank or black` for more.  It's
+   also worth re-checking your WiFi settings, since they won't carry over to a
+   freshly imaged card.