How the Sky Memo S Works for Astrophotography
Due to the rotation of the Earth, stars are not stationary . They appear to circle around the celestial
poles of the Earth (Fig1). Thus, being very faint and constantly moving across the sky , stars are
impossible to be captured on photographs, unless the camera is able to track them steadily to
allow long exposure. Sky Memo S provides the solution. With the high precision motor and built-in
Polar Scope, Sky Memo S can be set to compensate exactly for the star movement by rotating
the camera in the direction opposite to that of the Earth (Fig 2). The result is, the celestial objects
appearing in the field of view of your camera do not move anymore and so, taking a picture with a
long exposure time is possible while star trails(Fig 1) are eliminated. Fig. 3 illustrates how rich and
sharp your night sky pictures can be with Sky Memo S. In addition, Sky Memo S is also capable
of tracking at solar and lunar speeds.
Introduction:
The Sky Memo S Body
1:Mode Dial 13: Mounting Platform
2:Mode Index 14: Locking Knob
3:Polar Scope Cap 15: Knurled Ring of Polar Scope
4:Battery Case Cover 16: Polar Scope
5:Polar Scope Cover 17: Date Graduation Circle
6:Mini USB Port 18: T ime Meridian Indicator
7:RJ-12 6-pins Auto-guider Interface 19: AAx4 Battery Case
8:DSLR Shutter Control Port 20: T ime Graduation Circle
9:3-Position Slide Switch 21: T ime Meridian Indicator Calibration Screw
10: Right Button and LED Indication 22: Polar Scope Calibration Screw
11:Left Button and LED Indication 23:Worm Gear Meshing Adjustment Screw
12: Clutch Knob 24: Socket for 3/8" Thread Screw
25: 1/4” to 3/8” Convert Screw Adapter
The Optional Accessories:
(The default included accessories
may vary . Please refer to local dealers for details).
Polar Scope Illuminator - T o provide lighting source for Polar
Scope.
Fine-T uning Mounting Assembly - T o mount a telescope with
¼” thread screw on the
Sky Memo S. Allows pointing and
fine-tuning pointing in two directions.
3/8” Ball Head Adapter - T o mount a standard camera ball-head
with 3/8” thread screw on the
Sky Memo S.
Equatorial Wedge
- T o adjust the latitude of the Sky Memo S for
polar alignment. Offers higher accuracy and stability than a
standard photo tripod head.
Counterweight - T o balance the telescope or camera loading
with 1kg counterweight.
1/4" to 3/8" Convert Screw Adapter - T o convert the default
socket for 3/8" thread screw to the socket for 1/4" thread screw in
order to mount the
Sky Memo S to a standard quick release plate
of the tripod with 1/4" thread screw .
DSLR Shutter Control Cable - T o connect the DSLR Shutter
Control Port of Sky Memo S to your DSLR's external shutter
control port. This allows Sky Memo S to directly control the
DSLR's shutter release with pre-programmed shutter interval.
Y ou can order an optional cable for your camera from your
local resellers. The Following list shows the cables that we
offer as optional items.
Preparation :
Setup T ripod:
Without T ilt-head: take a standard photo tripod or video tripod with a
3/8” connection screw. Spread the legs and secure the tripod legs at the
desired height to provide a stable support for your
Sky Memo S.
Assemble
Equatorial Wedge to the tripod as Fig 4.
With T ilt-head/Ball-head: T ake a standard photo tripod or video
tripod with T ilt-head or Ball-head. Spread the legs and secure the tripod
legs at the desired height to provide a stable support for your Sky Memo
S as Fig 5.
Mount Sky Memo S:
With Equatorial W edge: Make sure the 1/4" to 3/8" Convert Screw Adapter is not in the
3/8" threaded socket at the bottom side of the
Sky Memo S. If it is, use a Slot Screwdriver to
remove it. Mount the
Sky Memo S on the (optional) Equatorial Wedge (Fig 6). Make sure the
Stopper is facing forward. Then point the
Polar Scope to the direction of the North Pole (For
Northern Hemisphere observing) or South Pole (For Southern Hemisphere observing) (Fig 7).
Lastly , complete the Polar Alignment process (Please see
Polar Alignment session for
reference).
With Tilt-head/ Ball-head: Make sure the 1/4" to 3/8" Convert
Screw Adapter
is in the 3/8" threaded socket at the bottom of the
Sky Memo S. If it is not, use an Slot Screwdriver to install it. Mount
the
Sky Memo S to the quick release plate on the tripod. Then point
the Polar Scope to the direction of the North Pole (For Northern
Hemisphere observing) or South Pole (For Southern Hemisphere
observing) (Fig 8). Then complete the polar alignment process (Please
see
Polar Alignment session for reference).
Please DO NOT move the tripod or change the angle of Equatorial Wedge or
tilt-head in order to keep the polar alignment. IF you did, please redo the polar
alignment process.
Mount The Imaging Equipment:
Now you can mount your imaging equipment according to your need, including the Shutter
Control Cable,
as the following figures show . Y ou can contact Kenko T okina authorized
dealers to acquire the optional accessories as needed. During mounting, please DO NOT move
the tripod or change the angle of the
Equatorial Wedge or tilt-head in order to keep the polar
alignment.
For Astrophotography:
Sky Memo S +3/8” Ball Head Adapter + Ball head + Camera + Shutter Control Cable:
Note: Make sure the locking bolt of the Mounting Platform has locked on the indentation on the
side of the
3/8" Ball Head Adapter for better locking and support.
Sky Memo S + Fine-T uning Mounting Assembly + 1kg
Counterweight + T elescope:
Sky Memo S + Dovetail + Dual Ball Heads +Dual Cameras + Shutter Control Cable:
Sky Memo S + Fine-T uning Mounting Assembly +
Ball-Head + Camera+ T elescope (+ Auto-guider):
For Time-Lapse Photography:
(For reference only: you can assemble very different configurations to create more interesting
time-lapse photography)
Horizontal Rotation Time-Lapse Photography:
V ertical Rotation Time-Lapse Photography:
Provide Power Source:
Sky Memo S allows two power source options. One is inserting 4 AA type batteries; the other is
providing DC 5V through USB port (type mini-B). (Fig 15)
Start Using Sky Memo S
Quick Function Reference:
Mode Dial:
For power control and selection of pre-programmed modes.
3-Position Slide Switch: for selection of rotation direction and camera shutter interval.
Buttons: The Right / Left buttons are used for rotating in higher speed (about 12X celestial tracking speed).
LEDs : The LEDs built-in buttons provide the lighting source in the dark and indicate the device
status such as low battery and motor error .
Snap : This is a 2.5mm 3-segment stereo jack for connecting to a camera’ s shutter control port
to control camera shutter interval.
After finishing the preparation steps, you can start to enjoy the
Sky Memo S. Its major functions
are described as follows:
Main Function: Sky Memo S has a user-friendly Mode Dial and 3-Position Slide Switch to
allow users easy selection of the pre-programmed movement pattern. At the other side of the
Sky
Memo S,
the two buttons give direct access to higher speed movement for quick positioning.
Mode Dial: Used to turn on/off power and select the desired modes shown in table 1. When the
Mode Index is pointing at OFF, the mount has no power . If rotated to other modes besides the
OFF mode, the power is turned on. The LED on the Mode Dial will light up to indicate the current
mode, and the LED on the buttons will light up, too. Meanwhile,
Sky Memo S will start tracking
at the constant speed corresponding to the mode selected (Please refer to table 1).
.
.
3-Position Slide Switch: Selects the rotation direction of the Sky Memo S and the camera
shutter interval. When the switch is slid to
N or TIMELAPSE, the Sky Memo S will rotate in
the astronomical tracking direction in the Northern Hemisphere, which is counter-clockwise
around the North Celestial Pole; when the switch is slid to
S, the mount will rotate in the
astronomical tracking direction in the Southern Hemisphere, which is clockwise around the South
Celestial Pole.
Right/Left Buttons: Used to rotate the Sky Memo S at the highest speed for easier
positioning towards the desired object. When the Right Button is pushed, the
Sky Memo S will
rotate at 12-time sidereal rate and in the same direction as when sliding the switch to
N or
TIMELAPSE; when Left Button is pushed, the Sky Memo S will rotate at 12-time sidereal rate
and in the same direction as when the switch is slid to
S;
SNAP (DSLR Shutter Control Port): Sky Memo S provides a camera shutter control
interface to control the shutter interval. The SNAP port is a 2.5 mm 3-segment stereo jack and the
trigger signal connects to the tip and base segments. By using the proper
Shutter Control
Cable
, the mount can control the camera's shutter release ( please refer to DSLR Shutter
Control Cable in the Optional Accessories).
The Shutter interval period of every selected
mode has been pre-programmed. Please refer to T able 1 for detail. For example, when the
Mode
Dial
is set to Mode and Slide Switch is set to N, the shutter interval period is 100
seconds, or 50 seconds if the
Slide Switch is set to TIMELAPSE (See T able 1). whenever any
change is applied to the buttons, mode dial, or switch, the timer is reset and the selected shutter
interval period will restart from 0 sec.
Osc Range: T o avoid the shutter release cable from twisting after a long period of use under the
Astrophotography applications,
Sky Memo S will reverse after reaching 360° rotation. That is, for
Mode and 0.5X, Sky Memo S will oscillate within a 360° range. For the other
modes, in order to provide more attractive scene while filming for time-lapse photography , under
time-lapse applications such as Mode 2X, 6X and 12X,
Sky Memo S will oscillate within
180°(See T able 1). Every button pushed or mode changed will reset the starting point of the range.
For example, when the
Mode Dial is set at 6X and Slide Switch at N, the position where the
particular mode is entered will be the left boundary of the oscillation. That is, it will rotate to the
right first until it reaches 180°, then oscillates within this range (Fig 21 & 22) . If any button is
pushed, the position at which the button is released will become the new left boundary of the 180°
range. If the switch is set at
S, it will rotate to the left first until it reaches 180°, then reverse the
direction for another 180°, and repeat the cycle (Fig 21 & 22).
Auto-Guider: Sky Memo S also contains auto-guiding interface to accept single axis (RA axis)
auto-guiding signal to provide more accurate celestial tracking for better quality of
astrophotography . The RJ-12 6-pin outlet is for connecting an autoguider . It is compatible with any
autoguider with a ST -4 type interface. This function only works in
Mode . For other modes,
the auto-guiding signal has no effect.
USB Port: Sky Memo S contains a USB port (T ype Mini-B) to support external USB power and
support firmware upgrade. Please refer to
"Firmware Upgrade" on page 26 .
Motor Status Detection: If the motor stalls (rotation speed does not reach 10% of the targeted
speed) over 5 seconds, in order to protect the motor and the mounted equipment,
Sky Memo S
will stop the motor and indicate "Motor Error" by flashing the LED on the buttons. Pushing buttons
or switching mode will restart the motor and restart the detection. Moreover , if the motor speed
error is over 5% ( if it is not within the 95%~105% of the targeted speed),
Sky Memo S will
indicate "Motor Error" by flashing the LED on the buttons, but it will not apply any change to the
motor control.
LED Indication: Sky Memo S has LEDs behind the buttons to indicating the current status.
There are three different ways the LEDs will light up. If the LEDs don't light up, the
Sky Memo S
is not in working mode.
Normal Status: LED will light up continuously at low intensity .
LED will light up at low intensity to provide light source in the dark when the motor status is normal
and the power level is normal.
W arning Status: LEDs will blink at a 0.5-second rate in two cases:
1.
Firmware upgrading: When updating the firmware, LEDs on the Sky Memo S will blink
as a warning not to turn off power .
2.
Battery low (The battery voltage is lower than roughly 4.5V): Sky Memo S supports
most of the AA batteries. When using rechargeable Nickel Metal Hydride (Ni-Mh) batteries, please
replace the batteries when it indicates low battery in order to protect the batteries from over
discharge. When using Alkaline batteries, the system will run normally for a while after indicating
battery low .
Motor Error Status: LED will blink at a 3-times-per-second rate in two cases:
1.
Motor speed accuracy violation: The motor speed error is over 5%. If this keeps
happening, the user may need to check for overloading (Max load is 5kg) or low battery l
2.
Motor stall: the motor stalls over 5 seconds. May be caused by external interference.
Please check if the mount is blocked by an external force.
Polar Alignment:
Before starting with the polar alignment procedure, please review the following figure to get
familiar with the scales and dials of the Polar Scope .
Use the built-in Polar Scope to complete the polar alignment. First, remove the Polar Scope
Cap
and insert the Polar Scope Illuminator (Fig 24). Rotate its Power Dial to turn on the
power to illuminate the
Polar Scope , then keep rotating the Power Dial until reaching optimal
illumination (Calibrate the
Polar Scope as needed. Please refer to " Appendix Ⅰ:Calibrate
The Polar Scope").
For Observing in The Northern Hemisphere:
find Polaris (the brightest star near the North
Celestial Pole) in the Polar Scope by adjusting the angle of the (optional)
Equatorial Wedge or
tilt-head on the tripod. Use third party Polaris Finder application or APP to find the corresponding
orientation of Polaris in the
Polar Scope by simply entering the date, time, longitude and latitude
of your observing location. Then move Polaris to that corresponding position in the Polar Scope
by using the fine-tuning movements of the
Equatorial Wedge or by moving the tilt-head on your
tripod(Fig 24). If you cannot acquire the application to find the orientation of the Polaris, please
refer to the "
The Orientation of Polaris in The Polar Scope " in the following portion.
For Observing in The Southern Hemisphere: locate in the Polar Scope the 4 dim stars
(Around Magnitude 5 to 6) which form the pattern “Octans” (see drawing in the Polar Scope as
Fig 26). Align the orientation of the “Octans” drawing to the 4 stars. Then move the 4 stars to the
4 small circles of the “Octans” drawing by using the horizontal adjustment knob to fine-tune the
Equatorial Wedge or by moving the tilt-head of your tripod.
The Orientation of Polaris in The Polar Scope
As Polaris is not located exactly at the North Celestial Pole, we can see it orbiting the North
Celestial Pole in a Polar Scope . The large circle seen in the center of the pattern in the Polar
Scope is a representation of Polaris’ orbit around the North Celestial Pole. When performing the
polar alignment process, it is necessary to determine the orientation of Polaris on the circle. We
can use the following 2 methods to get the orientation:
1. Locate both Polaris and Kochab in the sky near the North Celestial Pole. The relative position
of Kochab to Polaris is an approximation of the orientation of Polaris in the Polar Scope . For
example, if Kochab is at the 1 1 o’clock position of Polaris, then Polaris should also be placed at
the 1 1 o’clock position on the reticle circle (See Fig 27).
2. Use the built-in
Date Graduation Circle, Time Graduation Circle and Time Meridian
Indicator
to find the orientation of Polaris in the Polar Scope following the steps described below:
1. First, rotate the Wedge and adjust the latitude to bring Polaris within the field of view of the
Polar Scope.
2. Then rotate the
Date Graduation Circle to align Oct 31 to the 0 of the Time Graduation
Circle
and turn the Eyepiece/Mounting Platform to align the Time Meridian Indicator to the
0 of the
Time Meridian Circle (Fig 28). This is the date and time when the orientation of Polaris
is directly below the north pole ( 6 o'clock ).
3. At this point, the "6" in the reticle should point straight down (as shown in Fig. 29). If not so,
please refer to "
Appendix I: Calibrate the Polar Scope"
4.
Adjust the Date Graduation Circle . Find out the difference in degree between your
observing site longitude and the central meridian of your time zone and determine if you are on the
east or the west side of the central meridian. Now , adjust the
Date Graduation Circle
accordingly .
Example: If you are located in Prince Rupert, Canada, your longitude is 130.32°W . The standard
meridian (STDM) for this time zone is 120°W . This means Prince Rupert is about 10° westward in
relation to the STDM. T urn the Date Graduation Circle to W10 to compensate for this (Fig 30).
5. Match the Date Graduation Circle with your observing time by turning the eyepiece/
Mounting Platform. Please
DO NOT rotate Date Graduation Circle directly at this step. For
example, if your observing date is March 4 and observing time is 8:00PM (Standard T ime, that is
Daylight Time -1 if applied), then hold and turn the mounting platform until the 2
nd
scale mark of
March is aligned with the “20” on the Time Graduation Circle , which represents 8:00pm(Fig 31).
6. Put Polaris at the 6 o'clock position in the FOV of the Polar cope to finish the polar alignment.
Example for Astrophotography for Celestial T racking:
1. Assemble the tripod and Sky Memo S according to your need. Then finish the polar
alignment.
2. Mount the camera or telescope. Install the cables (
Shutter Control Cable and auto-guiding)
if needed.
3. Slide the 3-Position
Slide Switch to N if you are in Northern Hemisphere (Fig 32).
4. Rotate the
Mode Dial to Mode . The LED on the Mode Dial will light up Mode
. The LED in the buttons will light up, too. The
Sky Memo S will start tracking the celestial objects
at sidereal rate (86164 seconds per revolution, about 23.9 hours per revolution). At the same
time, it will assume control of the camera by activating the camera’s shutter release function with
an interval period of 100 seconds (as if you are pushing on the shutter release button of the
camera for 99.5 seconds and not pushing for 0.5 second and pushing again for 99.5 seconds).
5. Y ou can push the left and right buttons to move the
Sky Memo S at the highest speed (12
times sidereal rate) to approach the targeted object in RA direction. When you reach the targeted
object, release the button. The
Sky Memo S will continue celestial tracking and restart the shutter
interval period of 100 seconds.
Example for Time-Lapse Photography in Mode 12X:
1. Assemble the tripod and Sky Memo S according to your need.
2. Assemble the camera and connect the camera and
Sky Memo S with the Shutter Control
Cable.
3. Slide the Slide Switch to position N. Rotate the Mode Dial to Mode 12X.
4. Sky Memo S will rotate firstly to the right with a speed of 2 hour per revolution until reaching
180° , then oscillate within this range. (Fig 33). At the same time, it will assume control of the
camera by activating the camera’s shutter release function with an interval period of 2 seconds (as
if you are pushing on the shutter release button of the camera for 1.5 seconds, and not pushing
for 0.5 seconds and pushing again for 1.5 seconds).
Appendix I
Calibrate The Polar Scope
Before using the Polar Scope for polar alignment, the Polar Scope itself must be calibrated
to ensure the pattern in the
Polar Scope is aligned to the mount’s R.A. axis. The following
steps will outline how to calibrate the
Polar Scope. Calibrating during daytime is
strongly recommended :
1. Choose a fixed object (the Polaris at night, or a faraway object in daytime); orient Sky
Memo S
to put the crosshair of the Polar Scope exactly on the chosen object.
2. Rotate the mount in R.A. axis for half a turn.
3. If the object remains exactly behind the crosshair in the
Polar Scope after the rotation,
then it means the
Polar Scope is aligned to the R.A. axis and no calibration is needed.
4. If, during rotation, you see the object wandering off, calibration is needed. Y ou should
rotate the
Sky Memo S to find the point where the object is at the longest distance from the
crosshair center , and then you should move the crosshair halfway towards the object (Fig 35),
using the 3 tiny adjustment screws on the side of the Polar Scope (Fig 34). A 1.5mm Allen
wrench is needed.
IMPORT ANT W ARNING: Adjusting with the very small Allen screws is delicate. Read the note
below .
5. Repeat steps 1 to 4 a few times until the object remains at the center of the reticle when
rotating the mount in R.A. axis.
6. T urn the
Date Graduation Circle to align Oct 31 to the 0 of the Time Graduation
Circle.
Then hold the Date Graduation Circle and turn the eyepiece/Mounting Platform to
align the
Time Meridian Indicator to the 0 of the T ime Meridian Circle (Fig 36). Then,
when looking through the eyepiece, you should see the pattern aligned as shown in Fig 37. If the
pattern is oriented differently , then scales need readjustment. T o readjust, turn the
Date
Graduation Circle
to align Oct 31 to the 0 of the Time Graduation Circle. Then hold it and
turn the eyepiece/mounting platform to orient the pattern in the position shown in Fig 36. Loosen
the
Time Meridian Indicator Calibration Screw and move the meridian indicator to align it
to the 0 of the
Time Meridian Circle without turning the Date Graduation Circle and
Eyepiece/Mounting Platform. T ighten the T ime Meridian Indicator calibration screw . See
through the eyepiece. Now the pattern should still be in the right position.
Note:
• When adjusting the Allen screws, loosen one screw only ¼ of a turn, and then tighten the
other two gently .
• Do not over tighten the Allen screws; it might damage the pattern plate in the Polar Scope.
• Do not loosen one screw completely or loosen more than one screw at a time; otherwise,
the pattern plate in the
Polar Scope will be disengaged and further adjustment is impossible.
• If the pattern plate does disengage, remove the
Polar Scope’s eyepiece by turning the
Knurled Ring counterclockwise and then engage the pattern plate again.
• It is recommended to do this calibration at daytime, aiming at a point object (such as a distant
rooftop) because the delicate operation with the tiny Allen screws is even more delicate in the
dark.
Appendix I I
Fine-T uning Mounting Assembly:
The Fine-T uning Mounting Assembly connects a telescope to Sky Memo S and allows rotation in
the other direction (at 90°, DEC direction). Y ou can adjust the tightness of the rotation with the
clutch knob. Y ou also can fine-tune the camera or telescope orientation slightly in DEC direction
by using the fine-tuning knob. Y ou can also remove the Fine-T uning ¼’’ Mounting Element from
the dovetail and then mount two ball heads on the dovetail to carry two cameras or one camera
and another instrument. Y ou can also use the Fine-T uning ¼’’ Mounting Element at one side and
use ball head at the other side. Y ou can implement various combinations to fit your needs.
Equatorial Wedge:
The
Equatorial Wedge is a device to adjust the latitude for polar alignment. Rotate the
Latitude Adjustment Knob can adjust the latitude of the
Sky Memo S indicated by the Latitude
Indicator . The range is from 0° to 90°. The Horizontal Adjustment Knob can adjust the Wedge to
rotate to right or left horizontally . The Horizontal bubble is for checking if the base plate of the
wedge is horizontal. The accuracy is 1°. When you install the
Mounting Plate on the Sky
Memo S
, Make sure the Stopper is facing forward as Fig 39 shows to avoid equipment
slippage, before you fasten the Locking Knob.
32