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- share what my current astrophbotography rigs are
- outline my autoguiding set up
- briefly explore why I want to do autoguiding
- give detailed autoguiding workflow notes based on the equipment I am using
Let me remind you - this is my current astrophotography kit
- Canon 800D (which is about to be astro-modified)
- Samyang 135 and 14mm lenses at F/2
- Canon 22 and 50mm prime lenses at F/2.8
- Zenithstar 61ii with 61A field flattener
- SkyWatcher Star Adventurer 2i
- Ioptron skytracker
- EQM-35-PRO mount
- Optolong L-Pro filter - broadband
- Optolong L-enHance filter - narrowband
- Celestron Lithium Pro powertank
- Skywatcher Power tank
- Four 26,800 mAh power bands
- Dew band heaters for refractor and samyang 135mm lens
- Carbon fibre benro tripod
- ASIair mini
- ZWO 120mm mini guide cam
- RVO 32mm f/2 128mm FL Guide scope
Connecting equipment together
1. From back of ZWO 120mm mini guide camera – usb cable to ASIair mini usb slot
2. ST4 cable from guide cam to SWSA 2i tracker OR USB/RJ45 cable from ASIair USB slot to controller unit on EQM-35-PRO mount
3. From Canon 800D dslr – cable from USB port to ASIair mini USB slot
4. To ASIair mini – 12v cable from Celestron Lithium Pro power tank
5. USB storage drive into spare USB slot on ASIair mini
6. From separate power banks on tripod legs and/or Skywatcher power tank – (a) dummy battery USB cable to Canon 800 dslr (b) Dew heater bands for guide scope and Samyang lens or zenithstar 61ii
7. Ensure all cables will rotate freely without snagging
## 1. Equipment Setup (First Time or After Changes)
Go to **
Equipment** tab:
### Mount
* Select your **mount brand/model**
* Connection type: USB / EQMod / Serial
* Tap **Connect**
* Set **Mount Type = EQ**
* Confirm **Tracking = Sidereal**
###
Cameras -
* Connect **Main Camera**
* Connect **Guide
Camera**
* Set: Gain (typical: 100–120 for ZWO cameras)
###
Guide Scope
* Enter **focal length**
* Guide camera pixel size should auto-fill
###
Location & Time*
Confirm:
Latitude / Longitude Time zone
* Daylight Saving (ON if applicable)
## 2. Rough Polar Alignment (Manual)
Before
software alignment: Level the tripod -
Point the mount **roughly toward Polaris** (or south celestial pole)
Set mount to
**Home Position**
*
Counterweight down
* Scope
pointing north
* RA = 0,
DEC = 90 (or mount default)
Notes - ✔ Balance slightly east-heavy DEC: slightly north-heavy ✔ Cables secured (no drag) ✔ Guide scope solid (no flex)
❌ Neutral balance = DEC backlash nightmare.
## 3. Focus guide cam/guide scope
*Switch off both cameras in app
*select guide cam to main cam
*test shots to focus guide cam
*switch back to correct cameras
*Dark library - ON
(Aim for low star size/high peak value) – set
gain 50 - 60– affects star size – aiming for star value 2 or 3 and
<5. Select bin 1 for guide scope (bin 2 if stars faint or using
narrowband filter).
To focus
properly - Point at
a star-rich area Set: Exposure: 1–2s Gain: 60–70 Gamma – 50
Adjust focus
until: Stars are small and round Not donuts Not bloated
👉 If stars look like fuzz or blobs, guiding will never
be good.)
## 4. ASIAIR Polar Alignment (Software)
1. Select **Main Camera** (not guide camera)
2. Tap **Start**
3. ASIAIR will: Take image
Plate solve Rotate RA
automatically (~60°)
### Adjust the mount
5. Follow on-screen arrows: adjust RA first and then Dec
6. Aim for: Error ≤ **1 arcmin** (good) **30 arcsec** (excellent)
RECHECK PA AFTER TIGHTENING BOLTS UP – REPEAT IT!
❗ Poor polar alignment causes: Declination drift Failed calibration Inconsistent guiding corrections
## 5. Go Back to Home Position
1. Tap
**Mount → Go Home**
2. Wait
until finished
This ensures
accurate GoTo and guiding.
## 6. Focus (Very Important)
### Rough
Focus
1. Go to **
Focus** - Select **Main Camera**
2. Exposure:
1–3 sec - Increase gain if needed
3. Adjust focuser until stars are small ### Fine Focus (Recommended) * Use **Bahtinov mask**
(Tap and hold
box – drag onto a star – tap zoom on LHS – let settle for 1 or 2 images – aim
to get lowest FWHM as possible)
## 8. Plate Solve & GoTo Target
1. Go to
*Preview**
2. Tap
**GoTo**
3. Search object (e.g. M31, M42)
4. Tap
**GoTo**
5. ASIAIR will: Slew Plate solve Re-center automatically Wait until **Error < 10–20 arcsec**
Goto Settings Use plate solve: ON Sync after solve: ON Search radius: 5° Downsample: 2
## 9. Take a Plate Solve Image
On the main
camera panel: Exposure: 2–3 s ISO: 1600
1.
Tap
Plate Solve - 📌 ASIAIR takes an image and analyses
the star pattern
2.
Plate Solve & Sync If the solve succeeds: ASIAIR syncs the mount *Coordinates are corrected *See a green solve confirmation
If the
target is not centred: *ASIAIR automatically offers Recentre *Tap Recentre - It will: Slew
slightly Re-solve
Repeat until centred 🎯 Result: target centred within a few arcseconds
3. Verify
Framing (Optional but Recommended)
Take another
Preview image Confirm: *Target
position *Rotation / framing Use Framing Assistant Or manually nudge mount and re-solve
## 10. Guiding Setup & Calibration
Before calibrating: Point near: Celestial
equator Meridian Declination between
–20° and +20°
1. Go to **Guide**
2. Select **Guide Camera**
3.clear calibration tab top right corner.
4. Double tap graph – check guide settings as follows:
- RA agg 60/70% Dec agg 50/60%
- Corrections – on
- Guiding rate (under mount tab) x0.5
- Calibration rate (try 750 first)2000
- Max RA duration: 200 ms
- Max DEC duration: 200 ms
- DEC mode: auto (👉 Choose North or South only based on which way DEC drift naturally goes after PA.❌ Avoid DEC Auto unless PA is excellent.)
- Backlash compensation: OFF
- Multi-star guiding: ON (if available in your app version)
if imaging towards zenith > calibration number
5.
Exposure: * 1–2 sec (start with 1.5s)
6. Tap **Calibrate** * Happens once per session or
target
7. After
calibration completes, tap **Start Guiding*
**Very important:** After guiding starts, watch DEC drift for ~2 min:
* If DEC slowly drifts **north**, set **DEC South only**
* If DEC drifts **south**, set **DEC North only**
### Good
guiding values
* Total RMS: * **<
1.5″** = good * **< 1.0″** =
excellent (depends on mount) aiming for calibration in <18 steps Less than 4 steps = poor calibration –
reduce calibration to smaller number. Too many steps - > calibration number
Spikey blue
RA lines – decrease RA agg first; then if no effect - alter exposure to 2” or
mount speed to 0.75 or 0.25
Blue line
pulses oscillating same direction - > aggression. Peaks either side of line
– decrease aggressiveness
Aim for star
peak 80 – 200 for proper lock on
## 11. Imaging Settings (Autorun Preparation)
Go to **Autorun**
### Camera settings
- * Gain: 100–120 (typical)
- * Offset: default
- * Exposure time:
- * Broadband: 60–180s
- * Narrowband: 180–300s (if guided well)
- * Guide restart if lost Optional: * Meridian Flip (highly recommended)
- * Auto-shutdown at end
## 12. In **Autorun** tab:
1.
Select: * Target * Camera
* Filter
2. Set: * Number of frames (e.g. 50 × 120s) (do
in blocks of 30 minutes and then check cables, focus, etc before starting next
thirty minute block)
3.
Enable:
- * Dithering (every 1–2 frames)
- *dithering threshold – 1.2”
- * Auto-centre
- * Guide restart if lost
- *First delay – 15”
- *Interval – 3” NOTE: Dither less often for long subs
4. Optional:
- * Meridian Flip (highly recommended) – flip at 0d;
- * recalibrate guiding - YES
- * Auto-shutdown at end
5. do test image and check histogram – zoom in check no star trailing - if so – stop
guiding – refocus main camera lens/refractor with Bahtinov mask – restart
guiding – test shot
## 12. Start Imaging!
1. Confirm:
- * Guiding is active
- * Target centred
- * Focus is good
2. Tap **▶ Start Autorun**
ASIAIR will now:
- * Capture images
- * Dither
- * Re-centre if needed
- * Handle meridian flip (if enabled)
3. study
guide graph – see section ## 9 above
## 13. End of Session
After Autorun finishes:
- * Stop guiding
- * Park mount
- * Power off ASIAIR
🔄 WHEN TO PLATE SOLVE AGAIN
Plate solve again:
- *After every GoTo
- *After meridian flip
- *If target drifts off centre
- *When changing targets
Do NOT plate solve continuously during guiding.
🔍 What “Good” Looks Like with EQM-35-PRO
With a 128 mm guide scope + ASI120MM Mini:
- RMS total: 0.6–1.3″
(good)
- RA dominates error
- No oscillation pattern
- Stable star count (not dropping)
- DEC mostly flat with occasional
bumps
🚨 COMMON MISTAKES (Very Common)
❌ Trying to guide before solving or trying to guide with unfocused stars
❌ Main camera out of focus or loose guide scope
❌ Exposure too short (<1s)
❌ Pointing near celestial pole when doing calibration
❌ over-aggressive RA/Dec settings
❌ expecting perfect guiding in bad seeing
❌ rotating guide scope after doing calibration
❌ not balancing mount to be RA east heavy; or north or south heavy in Dec OR making balance neutral!
for first
solve
❌ Forgetting to tap Recentre
If getting trailing or inaccurate guiding, initially check
1. all settings are switched on in app - e.g. main cam, mount and guide cam
2. correct focal lengths entered in various tabs (wrong ones will lead to failed calibration)
3. focus is absolute on both cameras - poor focus can lead to failing plate solving
4.
settings in app not interfering
5. cables are not snagging anywhere around mount
6. Mount is is powered and working. Ditto with ASIair mini
7. Internet signal still established between app and ASIair mini
8. Dec is in one direction and not auto - so north or south
9. RA shows a sawtooth pattern - then RA is too aggressive - reduce the RA aggressiveness
10. plate solving fails due to low exposure
11. star elongation/trailing = poor polar alignment - redo PA
🧠 Quick Mental Model
- GoTo = get close
- Plate solve = know exactly where you are
- Recenter = put target dead center
- Guide = stay there
