materi workshop lunar crescent
DESCRIPTION
Materi Workshop Lunar CrescentTRANSCRIPT
Lunar Crescent Workshop
Thierry Legault
Surabaya, Indonesia
April 26-28 2014
Edition 3
Lunar crescent workshop - Thierry Legault 2014 1
Agenda: day 1
• The Moon and the crescent:
– Basic notions
– Using Stellarium planetarium program
– The lunar phases
– Seeing and imaging the crescent
• The GM8 mount and the Gemini2 system:
– assembly and installation
– polar alignment
• Outdoor practice with GM8 and Gemini2
Lunar crescent workshop - Thierry Legault 2014 2
Agenda: day 2
• Imaging:
– Setting the telescope
– Making and using the solar filter and the sunshield
– Adjusting the solar and lunar rates
– Pointing the Sun and the Moon
– Checking the celestial coordinates
– Using the video camera
– Processing the video sequences
• Outdoor practice with GM8 (optional)
Lunar crescent workshop - Thierry Legault 2014 3
Agenda: day 3
• Outdoor practice of lunar video acquisition
• Processing the video sequences
• Workshop feedback/wrap-up
Lunar crescent workshop - Thierry Legault 2014 4
Basic notions:
angles in astronomy
Lunar crescent workshop - Thierry Legault 2014 5
• An angle represents the apparent size of an object or the apparent distance
between two objects
• Moon = Sun = ½° diameter
• The angle between the Moon and the Sun is called the Elongation
Basic notions:
the Universal Time (UTC)
Lunar crescent workshop - Thierry Legault 2014 6
• UTC = Universal Time Coordinated
• Reference for astronomical and scientific/technical world
• Formerly: Greenwich Mean Time (GMT)
• West Indonesia = UTC + 7h
• Central Indonesia = UTC + 8h
• East Indonesia = UTC + 9h
The Moon and the crescent:
using Stellarium
Lunar crescent workshop - Thierry Legault 2014 7
Startup
The Moon and the crescent:
using Stellarium
Lunar crescent workshop - Thierry Legault 2014 8
Choosing location
The Moon and the crescent:
using Stellarium
Lunar crescent workshop - Thierry Legault 2014 9
Choosing location
The Moon and the crescent:
using Stellarium
Lunar crescent workshop - Thierry Legault 2014 10
Choosing date/time
The Moon and the crescent:
using Stellarium
Lunar crescent workshop - Thierry Legault 2014 11
Choosing date/time
The Moon and the crescent:
using Stellarium
Lunar crescent workshop - Thierry Legault 2014 12
Choosing speed
The Moon and the crescent:
using Stellarium
Lunar crescent workshop - Thierry Legault 2014 13
Finding object
The Moon and the crescent:
using Stellarium
Lunar crescent workshop - Thierry Legault 2014 14
Finding object
The Moon and the crescent:
the lunar phases
Lunar crescent workshop - Thierry Legault 2014 15
(source: http://upload.wikimedia.org/wikipedia/commons/4/46/Moon_phases_en.jpg)
The Moon and the crescent:
the lunar phases
Lunar crescent workshop - Thierry Legault 2014 16
• The phase is the fraction of the lunar disk illuminated by the Sun as seen from
Earth:
• Full Moon (all night) = 100%
• First/Last Quarter (evening/morning) = 50%
• Visible Crescent (sunrise/sunset) = a few percent
• New Moon (daytime) = less than 1%
• Total solar eclipse = 0%
• Average time between two Full Moon or two New Moon: 29d 12h 44m 2.9s
• New Moon can happen at any hour (day or night), depending on the date
The Moon and the crescent:
the lunar orbit
Lunar crescent workshop - Thierry Legault 2014 17
Inclination of lunar orbit ~ 5°
with respect to ecliptic (Earth orbit plane)
The Moon and the crescent:
the conjunction
Lunar crescent workshop - Thierry Legault 2014 18
• Conjunction (New Moon) happens when:
lunar ecliptic longitude = solar ecliptic longitude
• Topocentric conjunction: as seen from a specific place on Earth
• Geocentric conjunction: as seen from the center of the Earth
• Topocentric and geocentric times may differ by up to 4 hours, because of the
parallax
• At conjunction, the Elongation (EL) can take any value between -5° and +5°
• When EL is less than ½°, there is a solar eclipse (partial or total)
• The Age of the Moon is the time passed after conjunction
• The EL increases with the Age, at an average of 12°/day
• Crescent brightness and thickness increase with EL
• Solar glare decrease with EL
The Moon and the crescent:
the elongation in Stellarium
Lunar crescent workshop - Thierry Legault 2014 19
The Moon and the crescent:
visibility of the first thin crescent
Lunar crescent workshop - Thierry Legault 2014 20
Conjunction Later
The Moon and the crescent:
visibility of the first thin crescent
Lunar crescent workshop - Thierry Legault 2014 21
• Visibility with naked eye or binoculars needs:
• a dark sky => after sunset
• the Moon a few degrees above the horizon
• This implies a lower limit to EL => 12 hours minimum after conjunction
• Moonset (Moon at horizon) is invisible because of atmospheric extinction
(absorption of light)
• Transparency of the atmosphere is very important:
• no clouds
• no fog, smoke, pollution, humidity => blue sky even close to horizon
• moutain sites are often better (if no high clouds)
The Moon and the crescent:
the conjunction crescent (1/2)
Lunar crescent workshop - Thierry Legault 2014 22
• EL is always less than 5°
• The Moon and the Sun set almost at the same moment
• The conjunction crescent is detectable in daylight only with photography
• Visibility with the eye (naked or aided with telescope) is physically impossible
• Daylight photography needs infrared filter (and monochrome sensor, sensitive to
infreared) to decrease the brightness of the blue sky
The Moon and the crescent:
the conjunction crescent (2/2)
Lunar crescent workshop - Thierry Legault 2014 23
• The EL must not be too small
• World record so far: EL = 4.2°
• Transparency of the atmosphere is critical:
• no clouds
• no fog, smoke, pollution, humidity => blue sky even close to the horizon
• moutain sites are often better (if no high clouds)
The Moon and the crescent:
topocentric conjunction time
Lunar crescent workshop - Thierry Legault 2014 24
Find the time when Ecliptic Topocentric longitude of Moon and Sun are closest
The Moon and the crescent:
topocentric conjunction time
Lunar crescent workshop - Thierry Legault 2014 25
Find the time when Ecliptic Topocentric longitude of Moon and Sun are closest
The Moon and the crescent:
topocentric conjunction time
Lunar crescent workshop - Thierry Legault 2014 26
Find the time when Ecliptic Topocentric longitude of Moon and Sun are closest
The Moon and the crescent:
topocentric conjunction time
Lunar crescent workshop - Thierry Legault 2014 27
Find the time when Ecliptic Topocentric longitude of Moon and Sun are closest
The Moon and the crescent:
visibility charts
Lunar crescent workshop - Thierry Legault 2014 28
http://www.icoproject.org/
http://www.staff.science.uu.nl/~gent0113/islam/islam_lunvis.htm
Charts are approximations based on past experience and lunar position calculations
The Moon and the crescent:
visibility charts
Lunar crescent workshop - Thierry Legault 2014 29
The Moon and the crescent:
visibility charts
Lunar crescent workshop - Thierry Legault 2014 30
The Moon and the crescent:
visibility charts
Lunar crescent workshop - Thierry Legault 2014 31
The Moon and the crescent:
visibility charts
Lunar crescent workshop - Thierry Legault 2014 32
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 33
Deploy the tripod legs
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 34
Extend the tripod legs
Do not install the tripod
on loose or unstable
ground where the tripod
can sink or slide
(sand, mud, gravel…)
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 35
Install the mount on the tripod and tighten the 3 screws
The GM8 mount:
the axis of the mount
Lunar crescent workshop - Thierry Legault 2014 36
Movement axis:
- RA = Right Ascension
- DEC = Declination (δ)
Polar alignment axis:
- AZ = Azimuth
- LAT = Latitude
The GM8 mount:
the equatorial coordinates
Lunar crescent workshop - Thierry Legault 2014 37
RA is expressed in hour/min/sec
05h 34m 56s
Range: 0 to 23h 59m 59s
DEC is expressed in degrees/min/sec
45° 12’ 09’’
Range : -90° to +90°
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 38
Direct the polar axis leg to South for the southern hemisphere (North for northern hem.)
with the help of the compass
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 39
Adjust the tripod legs for horizontality (2 bubble levels)
Bad Good
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 40
Pre-adjust the latitude of the observation site with the LAT knob and scale
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 41
Use a bubble level and a triangle (cut according to the latitude) to adjust the latitude.
If necessary, use the polar axis leg extension
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 42
The latitude triangle
Surabaya example: latitude = 7.25°; tan(7.25°) = 0.127; 200*0.127 = 25.4 mm
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 43
Screw the counterweight bar and install the counterweight
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 44
Install the telescope (« CWD » position = CounterWeight Down)
The telescope:
components
Lunar crescent workshop - Thierry Legault 2014 45
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 46
Unscrew RA knob, adjust counterweight balance.
Check that the counterweight does not touch the tripod leg.
Put the mount in « CWD » position. Screw RA and DEC knobs.
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 47
Install the control panel.
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 48
Screw the RA motor.
Plug the RA cord between the control panel and the RA motor
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 49
Screw the DEC motor.
Plug the DEC cord between the control panel and the DEC motor
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 50
Plug the hand controller in « Graphic HC ».
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 51
Plug the GPS in « Serial port 1 »
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 52
Plug the 12V power supply
The GM8 mount:
The Gemini 2 system
Lunar crescent workshop - Thierry Legault 2014 53
Complete user manual:
http://www.gemini-2.com/
The Gemini 2:
initialization
Lunar crescent workshop - Thierry Legault 2014 54
Switch on the mount while in « CWD » position
Let the star display pass
The Gemini 2:
initialization
Lunar crescent workshop - Thierry Legault 2014 55
Press « cold start », « Back »
The Gemini 2:
initialization
Lunar crescent workshop - Thierry Legault 2014 56
Press « Back » again to go to the Main Menu page
The Gemini 2:
site check
Lunar crescent workshop - Thierry Legault 2014 57
From Main Menu page, press « Menu », « Site »
Press « Query GPS » when outside and check coordinates and Timezone
The Gemini 2:
time check
Lunar crescent workshop - Thierry Legault 2014 58
From Main Menu page, press « Menu », « Time »
Check (or change) Timezone, Civil date and Civil Time, press « Set »
The Gemini 2:
mount parking
Lunar crescent workshop - Thierry Legault 2014 59
From Main Menu page, press « Menu », « Park », « Park at CWD Position »
The GM8 mount:
assembly and installation
Lunar crescent workshop - Thierry Legault 2014 60
Align the finder on a distant target (terrestrial at several km, or celestial)
The GM8 mount:
polar alignment (southern hemi.)
Lunar crescent workshop - Thierry Legault 2014 61
• Polar alignment consists in physically aligning the polar axis of the mount with the
polar axis of the Earth, so that:
• all stars can be perfectly tracked with the rotation of the RA axis of the mount
at sidereal rate (one turn in 23h 56m 4.09s)
• The « GOTO » system of the mount can point any celestial object with
sufficient accuracy
• Poor polar alignment leads to a drift of objects in the field of view (eyepiece or
camera)
• For crescent imaging, polar alignment shall be better than 3 arc minutes (1/20 °)
The GM8 mount:
setting the sidereal tracking rate
Lunar crescent workshop - Thierry Legault 2014 62
From Main Menu page, press « Menu », « Track », « Sidereal »
The GM8 mount:
polar alignment southern hemi.
Lunar crescent workshop - Thierry Legault 2014 63
Point a bright star at North and altitude between 30° and 60° (halfway between
horizon and zenith).
The GM8 mount:
polar alignment southern hemi.
Lunar crescent workshop - Thierry Legault 2014 64
Align the axis of the crosshair vertical and horizontal, focus the star and place the
star very pricesely in the center of crosshair square
The GM8 mount:
polar alignment southern hemi.
Lunar crescent workshop - Thierry Legault 2014 65
If the star drifts up, use the AZ knob to rotate the mount counterclockwise
If the star drifts down, use the AZ knob to rotate the mount clockwise
Repeat the corrections until there is no visible drift during at least 3 minutes
The GM8 mount:
polar alignment southern hemi.
Lunar crescent workshop - Thierry Legault 2014 66
If the star drifts up, use the AZ knob to rotate the mount counterclockwise
If the star drifts down, use the AZ knob to rotate the mount clockwise
Repeat the corrections until there is no visible drift during at least 3 minutes
The GM8 mount:
polar alignment southern hemi.
Lunar crescent workshop - Thierry Legault 2014 67
Point a bright star at East and low altitude (15 to 25°)
The GM8 mount:
polar alignment southern hemi.
Lunar crescent workshop - Thierry Legault 2014 68
If the star drifts left, use the Latitude knob to pull down the polar axis
If the star drifts right, use the Latitude knob to pull up the polar axis
Repeat the correction until there is no visible drift during at least 3 minutes
The GM8 mount:
polar alignment southern hemi.
Lunar crescent workshop - Thierry Legault 2014 69
If the star drifts left, use the Latitude knob to pull down the polar axis
If the star drifts right, use the Latitude knob to pull up the polar axis
Repeat the correction until there is no visible drift during at least 3 minutes
The GM8 mount:
polar alignment southern hemi.
Lunar crescent workshop - Thierry Legault 2014 70
Go back to the previous star and check the drift, etc.
Make adjustments until there is no visible drift on both stars during at least 3 min
The GM8 mount:
polar alignment northern hemi.
Lunar crescent workshop - Thierry Legault 2014 71
Point a bright star at South and altitude between 30° and 60° (halfway between
horizon and zenith).
The GM8 mount:
polar alignment northern hemi.
Lunar crescent workshop - Thierry Legault 2014 72
If the star drifts up, use the AZ knob to rotate the mount clockwise
If the star drifts down, use the AZ knob to rotate the mount counterclockwise
Repeat the corrections until there is no visible drift during at least 3 minutes
The GM8 mount:
polar alignment northern hemi.
Lunar crescent workshop - Thierry Legault 2014 73
If the star drifts up, use the AZ knob to rotate the mount clockwise
If the star drifts down, use the AZ knob to rotate the mount counterclockwise
Repeat the corrections until there is no visible drift during at least 3 minutes
The GM8 mount:
polar alignment northern hemi.
Lunar crescent workshop - Thierry Legault 2014 74
Point a bright star at East and low altitude (15 to 25°)
The GM8 mount:
polar alignment northern hemi.
Lunar crescent workshop - Thierry Legault 2014 75
If the star drifts left, use the Latitude knob to pull up the polar axis
If the star drifts right, use the Latitude knob to pull down the polar axis
Repeat the correction until there is no visible drift during at least 3 minutes
The GM8 mount:
polar alignment northern hemi.
Lunar crescent workshop - Thierry Legault 2014 76
If the star drifts left, use the Latitude knob to pull up the polar axis
If the star drifts right, use the Latitude knob to pull down the polar axis
Repeat the correction until there is no visible drift during at least 3 minutes
The GM8 mount:
polar alignment northern hemi.
Lunar crescent workshop - Thierry Legault 2014 77
Go back to the previous star and check the drift, etc.
Make adjustments until there is no visible drift on both stars during at least 3 min
The GM8 mount:
polar alignment
Lunar crescent workshop - Thierry Legault 2014 78
CAUTION:
If the mount or one leg of the tripod is moved,
even by 1 mm,
Alignment is LOST
Imaging:
setting the telescope
Lunar crescent workshop - Thierry Legault 2014 79
Imaging:
making the solar filter
Lunar crescent workshop - Thierry Legault 2014 80
Use the instruction sheet provided with the filter:
http://www.baader-planetarium.com/sofifolie/bauanleitung_e.htm
Internal diameter of housing matches the external diameter of the end of telescope
Imaging:
making the sun shield
Lunar crescent workshop - Thierry Legault 2014 81
Use currugated cardboard roll, width at least 1.20 m
Imaging:
making the sun shield
Lunar crescent workshop - Thierry Legault 2014 82
Cut cardboard at least 1.20m long, make a tube, insert it over the telescope shield
and fix the ends with cord
Imaging:
pointing the Sun
Lunar crescent workshop - Thierry Legault 2014 83
From Main Menu page, press « GOTO », « Solar system », « Sun »
Imaging:
setting the solar tracking rate
Lunar crescent workshop - Thierry Legault 2014 84
From Main Menu page, press « Menu », « Track », « Solar »
Imaging:
synchronizing on the Sun
Lunar crescent workshop - Thierry Legault 2014 85
From Main Menu page, press « Menu », « Align », « Synchronize »
The display comes back to Main Menu page saying: Sync Sun
Imaging:
pointing the Moon
Lunar crescent workshop - Thierry Legault 2014 86
From Main Menu page, press « GOTO », « Solar system », « Moon »
Imaging:
calculating the lunar tracking rate (1/3)
Lunar crescent workshop - Thierry Legault 2014 87
Note the RA/DE (of date) lunar coordinates in Stellarium, 1 hour before
and 1 hour after the imaging time (here: 2:46:25)
Imaging:
calculating the lunar tracking rate (2/3)
Lunar crescent workshop - Thierry Legault 2014 88
Input them in the lunar rate calculation Excel sheet
Imaging:
calculating the lunar tracking rate (3/3)
Lunar crescent workshop - Thierry Legault 2014 89
Press Menu, Track, User Define.
Input the calculated differences Delta RA and Delta DEC in the User
Define Rate page of Gemini2, with timespan = 2:00:00, then press « Set »
Recalculate every 1 hour or so
Imaging:
setting the lunar tracking rate
Lunar crescent workshop - Thierry Legault 2014 90
From Main Menu page, press « Menu », « Track », « Comet/User Defined »
Do NOT use « Lunar »
Imaging:
checking the lunar/solar coordinates
Lunar crescent workshop - Thierry Legault 2014 91
Compare Main Menu RA/DEC coordinates to RA/DE (of date) in Stellarium
Difference must be less than 1m / 15’
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 92
Pulg the camera to the computer and launch iCap software
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 93
View useful toolbars
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 94
View histogram
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 95
Choose record directory and video filename with time stamp
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 96
Choose frame rate as maximum possible (30)
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 97
Choose format AVI and Codec RGB24 (uncompressed)
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 98
Choose video sequence duration: click on Toggle Recording Control Dialog,
then on the little clock and input duration
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 99
Let gain at 0.00 dB, manual (no Auto)
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 100
Adjust exposure time so that histogram maximum is 2/3 to 3/4 of the range
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 101
Bad: underexposed Bad: overexposed
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 102
Launch video sequence acquisition with « start recording » button
Imaging:
video acquisition
Lunar crescent workshop - Thierry Legault 2014 103
View elapsed time and number of frames with Record Video File dialog box
Video processing step 1
Lunar crescent workshop - Thierry Legault 2014 104
Launch VirtualDub and open the AVI video file to process
Video processing step 2
Lunar crescent workshop - Thierry Legault 2014 105
Export to a BMP image sequence
Name: i
Minimum number of digits: 1
Video processing step 3
Lunar crescent workshop - Thierry Legault 2014 106
Export to a BMP image sequence and note the number of last frame (here 887),
Click OK and let the process finish (a few minutes needed)
Video processing step 4
Lunar crescent workshop - Thierry Legault 2014 107
Launch Iris and check the presence of the Command window
and the Threshold window
Video processing
Lunar crescent workshop - Thierry Legault 2014 108
Settings of Iris (to do once): set the working path = video directory
and file type = FIT
Video processing step 5
Lunar crescent workshop - Thierry Legault 2014 109
Convertion: in the command window, type convertbmp24 i i N
Press enter and let the process finish (a few minutes needed)
(N is the number of the last bmp file)
Video processing step 6
Lunar crescent workshop - Thierry Legault 2014 110
Stacking: in the command window, type add_norm i N
Press enter and let the process finish (a few minutes needed)
Video processing step 7
Lunar crescent workshop - Thierry Legault 2014 111
Flat correction: in the command window, type div flat 20000
Press enter
Note : to make the flat, see page 117
Video processing step 8
Lunar crescent workshop - Thierry Legault 2014 112
Background removal: click Processing, Wavelet
Video processing step 9
Lunar crescent workshop - Thierry Legault 2014 113
Background removal: slide Remain to 0 (left) and press OK
Video processing step 10
Lunar crescent workshop - Thierry Legault 2014 114
Background removal: in the Command window, type offset 16000
Press Enter
Slide the high threshold to the right (32767)
Video processing step 11
Lunar crescent workshop - Thierry Legault 2014 115
Slide little by little the high threshold to the left and the low threshold to the right
to increase contrast
Video processing step 12
Lunar crescent workshop - Thierry Legault 2014 116
Save the image in JPEG: click File then Save
Choose JPEG as file type and give a name
Video processing:
making the flat
Lunar crescent workshop - Thierry Legault 2014 117
Before the first lunar video acquisition, follow the sequence:
1. Goto Moon
2. With the hand controller AD buttons, move the mount so to change the AD coordinate to add
or remove 15 minutes (example: if AD shows 18:25:12, move the mount to see 18:10:xx or
18:40:xx)
3. Record a video sequence exactly like a lunar one and note its name
4. Process this sequence through steps 1 to 6
5. In the command window, type save flat and press Enter
The flat can be made once for the whole day
Imaging checklist
Lunar crescent workshop - Thierry Legault 2014 118
1. If necessary, switch on the mount (CWD position)
2. Install the solar filter
3. Point the Sun with GOTO
4. Focus the Sun through the eyepiece
5. Connect the video camera to the computer and launch iCap software
6. Adjust video camera parameters for good visibility of sunspots
7. Focus carefully on sunspots through the video image
8. Center the Sun in the camera frame with the hand controller buttons
9. « Synchronize » the Gemini2 on the Sun
10. check solar RA/DEC coordinates
11. Point the Moon with GOTO and check RA/DEC coordinates
12. Remove the solar filter
13. Calculate and set the lunar tracking rate
14. Adjust video camera parameters for lunar acquisition
15. Take video sequences of 1 minute long
16. Every hour or so, check focus and re-synchronize on the Sun (step 2 and more)
Possible mistakes and problems
Lunar crescent workshop - Thierry Legault 2014 119
Problem Symptom
Poor polar alignment Objects drift in sensor/eyepiece
Wrong tracking rate Objects drift in sensor/eyepiece
Wrong time or site Wrong direction when use of GOTO
Poor focus Objects fuzzy (or not visible) in
sensor/eyepiece
Solar filter not in place for Sun Danger for sensor or your eyes!!!!!!!!!!!!!!!!!!!!!!!
Solar filter in place for Moon Nothing visible (black image)
Mount axis not tighten Wrong direction when use of GOTO
Mount axis moved manually after
polar alignment/synchro
Wrong direction when use of GOTO
Tripod moved or az/lat knobs touched
after polar alignment
Polar alignment lost
Message « motor stalled » Motor disconnected
The 3 keys for success
Lunar crescent workshop - Thierry Legault 2014 120
Train
Train
Train
Lunar crescent workshop - Thierry Legault 2014 121
Lunar crescent workshop - Thierry Legault 2014 122
Notes
Lunar crescent workshop - Thierry Legault 2014 123
Notes
Lunar crescent workshop - Thierry Legault 2014 124
Notes
Lunar crescent workshop - Thierry Legault 2014 125
Notes