3D Printing – PekDar – Astrophotography Engineering

EQDIRect for NEQ and EQ mounts

PekDar — Mon, 30 Jun 2025 12:25:38 +0000

The GOTO controller is extremely convenient and practical to use, when you want to look at interesting night sky objects, with your own eye through the eyepiece mounted in the telescope’s focuser. The ability to quickly select an object using the GOTO controller, is invaluable. It’s way better using mount with PC and Here it comes the EQDIRect for NEQ and EQ mounts.

In astrophotography, however, the GOTO controller isn’t necessarily as convenient. I admit there were times when it actually got in my way.

I decided to remove the controller so it would no longer intermediate the mount control; its role has been taken over by Astroberry combined with an EQDirect solution. My own implementation is based on descriptions for EQDirect available on the Internet.

The topic seemed simple, however, when it came to actually building the device myself, things weren’t so obvious anymore. Some important information is missing online. It’s easy to make a mistake that could seriously damage the mount’s electronics, as well as the Astroberry or another computer to which the EQDirect is connected. Repairing these devices can be very expensive!

Once I had gathered all the necessary pieces of the “puzzle”, analyzed and double-checked the subject several times, I assembled the whole thing. Then, with a slightly trembling hand, I switched on the power to the mount.

Luckily, nothing exploded 😉 What’s more, everything works – and it works like a charm! The mount responds to and executes all commands issued to it by the KStars+EKOS duo, along with the EQMod with INDI driver, and all of this resides together in Astroberry.

EQDIRect for NEQ and EQ mounts – Astroberry configuration

Of course, EQDIRect will also work with ASCOM and other software that requires such a technical solution to control the Sky-Watcher EQ6, NEQ6Pro mounts.

It works really well, even in slightly freezing conditions – tested – see the attached photos 🙂

To protect the expensive mount from damage, my EQDIRect unit is equipped with several additional electrical protections.

Mount performs excellently in the field together with EQDirect when used together with PERUN II power bank.

If you are interested in acquiring EQDIRect made by me, please don’t hesitate to reach out me by filling out the contact form.

Homemade power banks

PekDar — Fri, 11 Oct 2024 13:31:00 +0000

During an astrophotography session in outdoors, smowhere in the field, especially in spring or autumn, there is dew.
A wet lens makes photography impossible, so you need to take care of the possibility of drying the lens and even better, prevent dew during the photo session.
A heater-tape powered from the USB port of the powerbank, is ideal for reducing dew on the lens and even eliminating it totally.

Mobile Power Bank with two USB fast charging ports
12 Ah

Over the years I have used a number of different, small travel powerbanks of commercial manufacture, for charging my phone or powering mentioned heater.
They all broke down after a period of two years of use except for one, which still works today. It is an exception, no longer available on the market for sale.
Each commercial powerbank broke down in almost the same way, for the same reasons. The first reason was the large amount of water accumulated on the unit (dew), led to a short circuit.
The second, more common reason for failure, was the negative temperature in which I used the powerbanks, a range of -1 to -8 C degree.

Mobile Power Bank with two USB fast charging ports
12 Ah

I struggled with trying myself to repair the defects once the manufacturer’s warranty had expired. For those units that survived I’ve sent with the warranty service, which most often returned my money instead of the repaired device. Every time I went to take a night shots of the sky, I wondered – which of the two powebanks would break down this time?
My irritation reached its peak, when both powerbanks died in the same night in use with -3C degree.
Commercial powerbanks that can work with negative temperatures, cost far too much in relation to the capacity and functionality they offer.

Mobile Power Bank with two USB fast charging ports
12 Ah

I sat down at my computer and started working on my own powerbank, that would not die during use in minus degrees. I defined my own requirements and after two months of work and after-hours digging in subject, I created a prototype that worked without much complaint. I knew that the prototype would have hidden flaws that I was not aware of. I thought, my children could be great testers of my idea. I made a copy for each of them and two pieces for myself.

Over more than a year of using all the units, design and functional flaws became apparent, which were easily corrected. During use, I came up with the idea to add a small PV panel that can charge the powerbank in outdoors under the sun light. It doesn’t give a lot of extra power, but it will always reduce a bit the power consumption from powerbank self.

Mobile Power Banks with two USB fast charging ports
12 Ah

My owne powerbanks I carried with me almost everywhere. I used them in negative temperatures range from -1C to -13C.
None of them failed. Only the capacity of the recycled power cells used decreased, which in most cases is typical, when you use used rather old power cells. Everything wears out. I only replaced the cells that were weaker and used the powerbank further.
Today I’m already using the new final version, which I’m very happy with and I’m not going to buy any more commercial powerbanks, that don’t meet my expectations.

It has only one disadvantage, it is a relatively large device compared to commercial ones of the same capacity, some how I had to pinch all the electronics, replaceable power cells and PV panel. Personally, the size doesn’t bother me. When I go outdoors to take photo shoots or for any other reason, I throw the powerbank in my backpack or bag and vayola ahead 🙂

The photos show power banks that I made for my children 🙂

Mobile Power Banks with two USB fast charging ports
12 Ah

The main functionalities and capabilities of the powerbank are:
– replacement of used cells with new ones, without replacing the entire powerbank, definitely reduces the cost of using it,
– use of different capacities of power cells available on the market. I can increase or decrease the capacity of the powerbank, I rather prefer to increase 😉
– PV panel always helps a little in charging devices and saves energy in the powerbank itself,
– USB-A charging ports support fast charging mode,
– ability to charge the powerbank in fast charging mode via the USB-C port,
– ability to charge the powerbank in standard mode via the micro-USB port,
– % level display of available energy.

PERUN II – Astrophotography Power Bank & Counterweight

PekDar — Sun, 15 Sep 2024 13:30:01 +0000

You can find many different power banks on the market. Unfortunately, none of them met my personal expectations in terms of Astrophotography Power Bank with available power, mobility and small size for mobile Astrophotography and Astronomy. Especially in the context of the possibility to take the power bank on board plane and to be comply with restrictions, requirements and rules present with airlines and security gates regulations.

PERUN II – 3D model

To cover defined above requirements and needs the „PERUN II”, was created, which is improved version of discontinued PERUN first version.

Why “Perun” name? It is the god of thunder and lightning of the ancient Slavic religion. The name reflects the nature of this project and a large amount of energy that has been accumulated in a really small volume of Perun.

While using the first version of PERUN, I carefully noted all its shortcomings and user suggestions, which became very valuable later.

After 2 years of work since first PERUN was released, the first beta version of PERUN II was created. The first prototype was very successful and quickly passed with several field tests. Soon after the second version of prototype was created and it was very close to final version – this version was so successful, that I decided to make it available to a few people who were awaiting with improved version… The third and last version of prototype which has already become the final version containing most of the improvements, based on the collected notes and valuable suggestions from users.

PERUN II arised

Compared to the first version of PERUN, I have added new functionalities reported by users and others based on my own needs, which as it turned out later, were also appreciated by users. This is how a new list of requirements was created, containing changes and improvements, constituting the new goal of the project.

Project goals – more important points

Power source for astronomy / astrophotography devices in the field, without access to a permanent power source.
Possibility to take PERUN II on board the plane, based on present (Feb. 2024) requirements and safety rules during travel with power banks.
Using a Perun as a counterweight to assembly on a rod counterbalance mount. Especially for mounts NEQ6 and iOptron.
Double amount of available power and the number of available power ports for devices by connecting two pcs of PERUN to each other.
Possibility to quickly charge a set of batteries, without removing them from the PERUN body.

Technical specification for Astrophotography Power Bank

PERUN II can use up to 6 pcs of batteries, model: NP-F950/960/970 or compatible, f.e.:

NP-F970 – battery – bottom view

They can be purchased in most stores offering photographic and film equipment.

NP-F970 – battery – top view

Battery technical specifications for model NP-F970. You must buy it separately by your self:

Lithium-ion battery.
7.2 VDC voltage.
8600mAh capacity.
Equipped with a chip, compatible with InfoLithium.
Standard warranty – 12 months.
Free from memory effect.
The max. of the power of six pcs of batteries: 371,5 Wh

To charge batteriesin 100% full you need to buy separately by your self NP-F standard charger or compatible.

Vendor charger – model: NP-F970

Optional – Dedicated fast battery charger for batteries model NPF-970 or compatible.

PERUN C970 – fast battery charger for batteries model NPF-970 or compatible

Approximately 9-10 hours of continuous shooting for the configuration:

CEM25P mount,
MGen II guider,
AITK HORIZON RGB CMOS camera

The body hole diameter fits the iOptron rod counterweight. After using a dedicated reduction, it also fits on the NEQ6Pro counterweight rod and compatible.

Tested and proven devices in cooperation with PERUN II:

Lacerta MGen2 + CCD (guider) camera,
Omegon Pro CCD (guider camera),
CMOS ATIK Horizon RGB camera,
ASI 2600MC Pro camera,
RaspBerry PI4 (Astroberry),
AsiAir (with maximum power requirements 5A),
AsiAir Plus (with maximum power requirements 5A),
Parallactic mount CEM25p,
Parallactic mount CEM26,
Parallactic mount HEQ5,
Parallactic mount NEQ6Pro,
Parallactic mount NYX-101,
2x USB heater,
Power source for mobile phone,
Power source for other mobile power banks charged with USB port

Body housing dimensions – without batteries, battery locks, switches, charging port cover and body locking screws.

PERUN II – Housing dimensions without external items

X → 124 [mm] +- 1 [mm]

Y → 134 [mm] +- 1 [mm]

Z → 56 [mm] +- 1 [mm]

Total dimensions of the body, including batteries (NPF-970 model) and elements protruding beyond the main outline of the body case:

PERUN II – Total body dimension including external items

X → 129 [mm] +- 1 [mm]

Y → 142 [mm] +- 1 [mm]

Z → 162 [mm] +- 1 [mm]

Functional specification for Astrophotography Power Bank

Input current filtering.
Output current filtering.
Over-voltage protection on power ports (12 VDC).
Over-voltage and over-current protection on input power converters.
Filtering out electromagnetic interference on power ports.
Filtering out electrical noise on power ports.
Two PWR converters working in parallel – in case of one PWR converter became failed*, PERUN II will continuous operational with half of the available power of 4 [A].
Main power switch (red).
Dedicated power switch for each power port.
Dedicated LED signaling of the power status of each port.
LED battery level indicator.
Dedicated port for fast charging batteries and connecting PERUN II (twice more available energy).
Possibility to take on board the plane.
Very high energy-to-weight ratio transported on board the aircraft.
Perun itself is a counterweight to the devices suspended on the mount. The more batteries used with Perun, the more counterbalanced it is. At the same time offering more energy at your disposal.
Batteries HOT-SWAP during operational.

* – depends on the nature of the converter failure.

Characteristics of PERUN II

The power source are batteries with a voltage of 7.2 VDC each. Connected in parallel.

During operation, the voltage level automatically decreases in according to the battery discharge state.

PERUN II – full load with 6 pcs of batteries, model: NP-F970

Summary of the currents of all connected devices in one time, must not exceed 8 [A].
Two PWR converters working in parallel – in case of one PWR converter became failed*, PERUN II will continuous operational with half ( 4 [A] ) of the available power.
Without load, PERUN II generates no heat. It heats up slightly during load, therefore does not require active cooling.
Has three 12VDC power ports. Each power port has a current protection of 5 [A]. The set includes one spare 5 [A] fuse.

PERUN II is able to handle momentary currents greater than the nominal operating current 8 [A]. However the connected devices, must be protected against damage.
Voltage range on the power ports has been set in between: 12.2 – 12.9 VDC,
LED battery level indicator,

PERUN II – LED battery level indicator and charging socket

Two USB 5VDC ports – power or charge any device connected to USB-A ports, f.e.:
- heater,
- mobile phone,
- another power bank.

USB ports can be load with a current of 3 [A], you can power or charge any device powered by a USB port in an accelerated mode if they recognize correctly the fast charging protocol.
The same charging port is also used to join PERUN II in a “chain” – doubling the available energy – look to the chapter “Joining PERUN II – twice as much available energy“

PERUN II – dedicated charging / joining port with batteries model NP-F970

Battery HOT-SWAP

If you have more than 6 pcs of batteries, you can replace the currently used ones, which are already discharged or close to running out of energy, with new, fully charged ones during the photo session.

You must remember that the batteries used with PERUN II are not perfect identical/equal (although they are the same model and product) and they discharge each other unequally. To avoid a situation, during battery replacement that, there is suddenly no energy to power the connected devices, replace the batteries one at a time.

The procedure for battery replacing during a astrophotography session is described in the user manual.

PERUN Charger 970 - Optional

Optionally, you can purchase a dedicated fast charger (PERUN C970) for NP-F970 or compatible batteries.

The PERUN C970 charger supports only batteries of the NP-F970 model or PERUN II compatible batteries. Using the charger with another battery model may damage the battery, charger and PERUN II, for which the author and the manufacturer are not responsible.

PERUN C970 charges the NP-F970 model battery to a maximum of approximately 80% +-5% of its capacity. The percentages given are indicative.

Specification - PERUN C970

External dimensions of the housing:

PERUN C970 – housing dimension

X → 205 [mm] +- 1 [mm]

Y → 56 [mm] +- 1[mm]

Z → 95 [mm] +- 1 [mm]

Total dimensions (including elements stick out beyond the main outline of the housing):

PERUN C970 – total dimensions – including elements stick out beyond the main outline of the housing

X → 208 [mm] +- 1 [mm]

Y → 61 [mm] +- 1 [mm]

Z → 95 [mm] +- 1 [mm]

The charger’s AC power socket is a standard, compatible with power sockets on PC power supplies.

There is a current protection device between the AC power socket and the main switch. Standard glass fuse 10 [A].

PERUN C970 – AC power socket with power switch

The charging process information display, represents information like:

Temperature inside the charger, right next to the power converters. The safe operating temperature range is 0 – 85 [C].
Value of current during battery charging process.
Value of voltage during battery charging process.

PERUN C970 – Charging process information display

Active cooling – PWM fan.

PERUN C970 – View of the fan

PERUN II and PERUN C970 – battery charging process

Joining PERUN II – twice as much available energy

If you have two pcs of PERUN II, you can connect / join them to get double amount of available energy and extend in double the operating time of your astrophotography set.

To connect / join PERUN II together, you will need a dedicated PERUN II charging / joining cable included with PERUN II set or included with PERUN C970.

The description how to connect PERUN II is described in the user manual.

PERUN II – stacked

Connecting / joining both PERUN II showed as example on the Figure provides discharge process in balance of both PERUN II and you can power up to 6 pcs devices! At the same time and each will receive as much energy as needed – with limit to max 5 [A] / power socket / device and max 8 [A] / one pcs of PERUN II.

Included

Body – six ports for a battery model: NP-F950 / 960/970, (batteries with a charger must be purchased separately),
PERUN II – Body
Two locks securing the batteries against uncontrolled sliding out of the port – in the case of reverse mounting on the counterweight rod,
PERUN – battery locks
Spare fuse,
PERUN / PRUN II – 5 Amps spare fuse
A set of three power cables, including one with a ferrite filter,
PERUN II – Power cable for devices
Two locking screws for the body to lock it on the counterweight rod,
PERUN II – locking screws for the body
Counterweight rod diameter reducer for mounts equipped with a counterweight rod with a diameter less than 19.9 mm, e.g. mounts: EQ, HEQ, NEQ.
PERUN II – Counterweight rod diameter adapter
PERUN / PERUN II – Adapter in use
Set of 6 pcs battery covers, model: NP-F970,

Comparison to other solutions

The comparison I will provide below is almost the same as in the publication regarding PERUN.

I’ve only updated the cost, based on the final price of the new version, which includes more electronics and additional devices.

Alternative solution, no longer available (checked 22/1/2024) with non valid price: https://www.ioptron.com/product-p/8128.htm

– PowerWeight^TM CW Battery – iOptron – has a maximum power of 96Wh with the price of 158 USD (old price from 2020, customs and vat tax excluded), which can be taken on board the plane.

In order to get the amount of required power comparable to what offer us a Perun, you need to purchase 4 pcs. PowerWeight^TM CW Battery, which gives us cost:

Astrophotography setup with NEQ6Pro mount, 2x PERUN II stacked, CMOS camera, 6 inch Telescope and Astroberry driver with own designed case box + some additional

4x96W = 384Wh –> cost 4×158 USD = 632 USD Gross, price 1Wh = 1,65 USD Gross

4 pcs of PowerWeight^TM CW Battery you can’t put as counterweight on the rod. Even if I use the counterbalance rod extension, we can fit a maximum of 2 pcs on it.

It only gives me half of the power I need to run my astrophotography setup, during the entire night (8 hours average of collecting lights).

– PERUN II – has maximum power 371.5Wh with price (199 EUR body + 132 EUR for 6 pcs battery pack = 331 EUR) – Total cost is 1Wh = 0,89 EUR.

Depend of the destination country… If we add customs duties and tax fees to the PowerWeightTM CW Battery, the difference will be even greater against of PERUN II. After this article, besides the price, I don’t think I need to mention the functional advantage of PERUN II.

PERUN volume shape, it takes less space than 1 pcs of PowerWeight^TM CW Battery !

Therefore, it is possible to add one more PERUN-s as a counterweight on a rod, which will provide total of 743Wh of power! If you could fit 3 pcs of Perun, you would have to change the Watt unit to kW! of power, on a piece of iron rod as a counterweight to my assembly.

PERUN is an uncompromising and unrivaled solution that guarantees me a power reserve for use in the field without access to a permanent power source.

If you are interested in to buy PERUN, please contact me. The e-mail address you can found in the footer of the page or you can full fill contact form. You can also contact me via Messenger / WhatsApp / Signal.

ATTENTION! – the prices given are indicative (with high accuracy). The final price valuation may differ slightly due to the inflation increase in the prices of components needed to build PERUN and their availability or availability of replacements and local TAX applicable.

Astroberry power supply – DIY

PekDar — Sat, 01 Apr 2023 20:28:26 +0000

Designed by me, the Astroberry power supply delivers 84 W of power, which is enough even when I connect additional devices to all four USB ports that are powered from those ports. The power supply’s output voltage is the standard 12 VDC.

The Raspberry Pi 4, which is the “heart” of Astroberry, is normally powered with 5 VDC. My own Astroberry design is powered by 12 VDC via an appropriate voltage converter; I’ll skip further details for now — that’s a topic for a separate article on my website, which is slowly taking shape. Its compact size allows me to take it anywhere.

I can and do use the built power supply to power any astrophotography rig. For almost a year it has worked very well every time I use it. So far it has never let me down.

PSU technical specification – Astroberry power supply – DIY

Power input

mains power supply 230[AC],
standard computer power socket,
current protection 630[mA],
anti-interference protection,
two-state rocker switch,

Power output

voltage: 12 [V] DC
max. current: 7 [A]
current protection: 7 [A]
electrical and electromagnetic interference protection
LED power status
2-pin male power socket, compatible with PERUN power socket and PERUN II, the same power patch cords of devices can be used.

External Power Supply for Laser Collimator modification – Practical DIY Guide

PekDar — Fri, 14 Jan 2022 16:09:16 +0000

Laser Collimator modification: The Button Cell Problem

Standard laser collimators (including the popular Baader Mark III) are powered by small LR44 or CR2032 button cells. These have two critical flaws in astrophotography:

Voltage Drop in Cold Weather: In freezing temperatures, their efficiency drops drastically, causing the laser to dim. A dim beam loses its definition, making it difficult to precisely judge the center of the mirror.
Short Lifespan: Batteries tend to die at the worst possible moment, and changing them in the dark risks mechanical shock to the collimator itself.

Engineering Solution: Constant Power Source

The goal of this modification is to replace the unstable chemical source with an external power supply [Describe briefly what you used: e.g., a 2x AA 1.5V battery pack or a 3V DC adapter]. This ensures constant laser spot brightness throughout the night, regardless of ambient temperature. Consistent voltage guarantees a sharp, focused beam, which is crucial for the precision of Newtonian optics alignment.

Warning:

Cable Drag Introducing a wire to a device that must remain perfectly axial involves mechanical risk. The weight or stiffness of the cable can cause slight flexure in the focuser drawtube or tilt the collimator itself within the sleeve.

The Solution: The wire must be lightweight and flexible. It is essential to support the cable (strain relief) by attaching it to the telescope tube (e.g., with Velcro) so that it exerts zero torque or pulling force on the collimator. Ignoring this physics principle will lead to false collimation readings.

The photo below shows a socket for three pcs of the SR batteries.

socket for 3 pcs of SR battery type

I decided that I would modify the power supply of my collimator, so that I would have easy access to popular and commonly available LR03 / AAA batteries or rechargeable battery. This is how my tiny-project with modernization of the power source of my collimator was created. More you can find below.

Necessary tools and items

1x self-designed and made battery cartridge,
2x screw with a cross head, dimensions of 3.85 mm fi head, 2 mm fi metric thread,
1x inner washer. dimension fi 2mm
a pair of wires with a section of 0.8 mm – external dimension,
1x DIP switch (on/off),
1x 3mm red LED (1.9-2.1VDC, max: 20 mA)
1x 270 Ohm resistor, 250mW
1x self-designed and made housing for the set of 3x AAA rechargeable battery / battery,

Set of needed items

Blender

The location of the battery in the collimator looks like a small sleeve shape. Originally there are 3 pcs batteries, model SR. I’ve measured the place and in the Blender program I designed a cartridge that will act as a connector for power supply cables and provide good wire contact.

With my example, I used 3 AAA rechargeable battery. The battery voltage is slightly lower (1.3 VDC) than the standard LR03 / AAA battery. Lets count:

3x rech. batt. AAA = 3,9VDC

Collimator with standard requirements to work needs:

3x SR 1,5VDC = 4,5VDC

The voltage difference is 0.6VDC it can be a lot, or not much, it depends on how you look at it. It’s just a laser, lower voltage will cause lower laser brightness but won’t prevent you from using it. The standard alkaline batteries with a voltage of 1.5VDC / piece provide the collimator factory voltage.

In order to be able to easily remove the batteries for charging, I used battery cradles. I thought it would be good to equip the power module with a DIP switch and a red LED, that would indicate the module’s operation. I have designed a housing that will fit all these things. The lid of the housing is sliding, so I can easily get inside to replace the batteries. The housing has a small handle in the shape of an ear through, which you can thread Velcro fastener. It will be possible to easily attach the power module to any mounting or telescope handle location, so that it does not prevent collimation process.

Blender 3D model

The photo below shows the printed models. Battery cartridge and a box with a lid.

3D printed battery supply and battery box with cover

It took me a while to figure out a way, to lead the power cables to the battery cartridge. After considering several options, I concluded that the best solution would be to drill a small hole in the laser power cap.

A drilled hole into a over

I threaded two wires through the drilled hole.

przewleczone przewody w wieczku

Let’s put it all together

I’ve connected three battery cradles in series with the electric cable, which is included in the set as a standard. I checked the quality of the connections with a multi-meter. I glued the sockets with the “droplet” glue to the bottom of the box. Next to the sockets, I screwed the power switch (DIP) and put on the red LED, the anode (+) of which I connected to the resistor and its corresponding to the switch pin. I’ve connected the cathode to the negative pole of the power circuit. By turning on the power to the entire system, I also power the LED diode, which signals the operation of the entire system.

Laser Collimator MKIII – Power supply box

I screwed the two ends of the wires to the battery cartridge. The negative from the bottom and the positive inside and locked it from the top with the screw, which is also the positive pole for the laser housing.

battery cartridge

I have inserted the battery cartridge into the place, where the batteries would normally be. Gently pressed a screwdriver on the top of cartridge, so that the screw on the front of the cartridge had good contact, with the negative pin of the power supply. I screwed the lid, where its spring pressed against the screw washer together with positive power cable where it was connected.

battery cartridge in the battery socket

Tests

Let’s check if it works. I’ve put on a 3x AAA rechargeable battery and turned on the power. The LED status flashed a beautiful red light. For a moment I watched if there would be some unwanted smell of burning electronics and searing smoke with my eyes…. Luckily, nothing like that happened. I turned on the laser and a beautiful red beam of focused light appeared on the top of my desk.

It works!

assembled prototype testing

Laser Collimator Mk III in action