Equipment – PekDar – Astrophotography Engineering

iOptron CEM25P Service – DEC Axis Bearings Replacement

PekDar — Sun, 28 Dec 2025 09:20:10 +0000

iOptron CEM25P

This document describes the replacement of a pair of DEC axle bearings, for the iOptron CEM25P mount. It certainly does not exhaust the topic, although I tried to include, in this description the most important information, that I was able to gather during my struggles, that I encountered during the replacement process of bearings.

Description of the problem: during rotation, bearings liked to “brake” the entire DEC axis.

After disassembling the axles and removing both bearings, turning them in hands, there was a slight resistance locally. These were poor quality products or damaged during assembly. Clearly, they had to be replaced with new, appropriate quality products. The method of disassembling the old and assembling new bearings is described below. Be aware that you can lost your warranty if you have.

ATTENTION! The following steps require some practice, if you do not confident to do it, will be better with assembly to trust someone, who is skilled enough and will not be more difficult for him to perform all the activities described below. Certainly, this description is not error-free, so be aware of it. I do not take any responsibility for any damages caused with use of this document.

Necessary tools and some chemicals

Multipurpose lithium grease I use.

Smar litowy uniwersalny CX80

A set of auxiliary tools:

Allen key set,
a small toothbrush,
pliers,
small angled pliers,
small wrench,
a small art brush,
metal hammer

Service Tools

New bearings, model: 6907 ZZ EZO, 1 pcs per axis and 6805 ZZ EZO, 1 pcs per axis. The photo below shows the new bearings.

iOptron CEM25P – DEC axis – new bearings
model: 6907 ZZ EZO, 6805 ZZ EZO

Disassembly the components of the DEC axis

Take a picture of the assembled mount, just before taking any action, so that after disassembling it into parts, you will know what state you should return to.

iOptron CEM25P

Remove both caps of the polar finder.

iOptron CEM25P – cap of the polar finder – back

iOptron CEM25P – cap of the polar finder – front

Manually unscrew the eyepiece of the polar finder.

iOptron CEM25P – eyepiece of the polar finder

Remove the DEC body cap using the small angled pliers.

iOptron CEM25P – DEC body cap

Unscrew the polar finder illuminator using the small angled pliers. Remember to not squeeze much the illuminator housing. Be gentle.

iOptron CEM25P – polar finder illuminator

Remove the two outer bolts connecting the DEC body to the RA axle body, using the right size allen key.

iOptron CEM25P – outer bolts

Remove the top inner screw using the right size allen key.

iOptron CEM25P – top inner screw

Remove the inner bottom bolt, that connects the two bodies using the right size allen key.

iOptron CEM25P – inner bottom bolt

With one hand, grab the DEC body and the other hand, on the RA axle body. Moving from side to side with the DEC body, pull off slowly, until all is removed from the RA sleeve.

iOptron CEM25P – DEC body removed

Use the Allen key to unscrew the 6 screws connecting the dovetail handle with the body of the DEC axle. Remove the handle.

iOptron CEM25P – dovetail handle

Remove the three bolts, securing the DEC axle gearwheel cover, using the right size of allen key.

iOptron – DEC axis – three bolts of the DEC cover

Kluczem imbusowym, odkręć trzy śruby blokujące koło zębate na tulei osi DEC.

iOptron – DEC axis – three screws securing the DEC axle gearwheel

Remove the gear wheel.

iOptron – DEC axis – gear wheel

Turn the DEC axle body over and using straight-nose pliers, unscrew the DEC bearing locking nut.

The photo below shows the nut removed,

Slide the sleeve off the body.

Remove both DEC axle bearings from their seats. It may happen that one of the bearings is factory fitted tight. Then use a hammer and a screwdriver with a wooden handle to very carefully bounce off bearing from the socket.

The photo shows both bearings that needs to be replaced.

Dimensions in [mm] of the smaller bearing.

Dimensions in [mm] of the larger bearing.

Assembly of new bearings and DEC axle components

Install new bearings on the sleeve and check that all components fit together.

Apply a small amount of grease to the bearing seat. Use a brush to spread it over the entire surface. This will make it easier to seat the bearing.

Slide the larger bearing into the seat. In my case, the dimensions of the bearing and the seat fit tightly. A bit of force was required to fit the bearing exactly into the seat. I put the handle of the tongs against the edge of the bearing and with a hammer tapped the handle with steady force, moving it around the edge of the bearing. This method is not perfect, but it has worked well.

Flip the DEC body over and slide the smaller bearing into the seat. Make sure it is well seated in place, checking visually, whether there are clear gaps between the bearing ring and the seat.

From the worm gear side, slide the DEC shaft sleeve into the bearing.

Screw the nut with the sleeve. It presses down and eliminates excessive play between the sleeve, bearings and the body.

Using long straight pliers, tighten the nut with measured force. Be very careful not to over tighten it, which will occurred with unwanted resistance. Can’t be screwed on too lightly, there may be occurred unwanted play.

iOptron – DEC axis – bearing locking nut

Install the DEC axis worm wheel gear.

iOptron – DEC axis – gear wheel

Screw in the three Allen locks and lock the gear. There may be unexpected resistance when rotating the body about the sleeve axis. IMPORTANT: Tighten the Allen screws until there is no resistance.

iOptron – DEC axis – three screws securing the DEC axle gearwheel

Screw in the polar finder lens.

iOptron CEM25P – polar finder lens

Apply a thin layer of grease to the sleeve of DEC axis.

iOptron CEM25P – thin layer of grease

Assembly the other half of the body.

iOptron – DEC axis – Assembly the other half of the body

Make sure that the screw inside body, hits the appropriate hole. Grip the bolt with a wrench and lightly screw it into the body.

iOptron – DEC axis – Grip the bolt with a wrench

iOptron CEM25P – screwing other half of the mount

Use the appropriate size Allen key to screw the other inner screw onto the body.

iOptron CEM25P – inner bottom bolt

Screw the body with the two longer screws using the appropriate size Allen key.

iOptron CEM25P – two, longer screws

Put on the cover of the RA axis worm wheel and screw it on with three Allen screws.

iOptron – DEC axis – three bolts of the DEC cover

Apply a thin layer of grease to the DEC sleeve.

iOptron – DEC axis – grease to the DEC sleeve

Use the Allen key to tighten the 6 screws connecting the dovetail handle with the DEC axle body.

iOptron CEM25P – dovetail handle

Attach the polar finder illuminator by hand or using small pliers.

iOptron CEM25P – polar finder illuminator

Attach the bottom DEC cover by hand or with a pair of pliers.

iOptron CEM25P – polar cover cap

Attach the polar finder cover.

iOptron CEM25P – cap of the polar finder – back

Test to verify the appropriate of the bearings replacement

Attach the mount to the tripod. Grab the body of the DEC axle with your hand, unlock it so that it can rotate freely. With your other hand, turn the dovetail handle. Pay attention to whether you feel any slightest resistance in a specific place when turning the handle. If you have followed all the steps in these instructions correctly, you should have the same freely rotating dovetail handle as in the video below has been shown. If it does then congratulations, great job!

The article describing the replacement of the RA axis bearings can be found here.

If you feel a local resistance while rotating the dovetail handle, think about whether all the activities you did. Maybe there was some of them, that could be called into question? If that’s the case, disassemble the DEC body and come back to the point, where it may seem that something is not what you expected. Pay attention to details, even the smallest dirt can affect the smoothness and fluency of rotation of the entire DEC axis.

Install the astronomical equipment on the assembly as you usually do. Start the mount and use the controller to make a few full turns in both directions. If during the rotation of the mount in the RA axis, there were no unexpected sounds of friction, scraping and the mount, did not stop unexpectedly, it can be said that the operation of replacing the bearings (in my opinion) was a completed with success.

Of course, the best and final test will be going out into the field, with full equipment and testing the equipment during beautiful night with stars.

Version: 1.1

Date: 10.04.2025

Author: Dariusz Krzempek

iOptron CEM 25P RA axle bearings replacement

PekDar — Sat, 06 Dec 2025 09:00:47 +0000

Introduction

This document describes the iOptron CEM 25P – RA axle bearings replacement of a pair of RA axis bearings in an iOptron CEM 25P mount. This DIY document certainly does not cover the topic exhaustively, but I have tried to include as much information as I was able to gather during the bearing replacement.

Description of the problem: during rotation, bearings liked to “brake” the entire RA axis. The symptom was present permanently especially at the temperature of 25C++

After disassembling the RA axis and removing both bearings, when rotating them by hand, a slight resistance could be felt in some places. These were either defective products or factory-induced damages acquired during product assembly.

The revealed defects had to be eliminated by replacing the faulty parts with new, high-quality ones. The method of dismantling the old bearings and installing the new ones is described below.

ATTENTION!

The following steps require a certain level of skill. If you do not feel confident, it is better to entrust the mount to someone who has experience in “tinkering” and will not find it difficult to perform all the steps described below. Be aware that this description is certainly not error-free. I take no responsibility for any damage resulting from the use of this document. You perform all actions at your own risk.

SynScan controller firmware update – NEQ6Pro

PekDar — Sat, 25 Oct 2025 11:51:00 +0000

WARNING – the author of this manual accepts no responsibility, for any damages that may occur as a result of following this manual. All actions described in this manual are undertaken at your own risk.

SynScan controller firmware update – Introduction

Starting from version 3.0, users can independently update the firmware of SynScan controllers for NEQ mounts. Simply download the latest software version from the Sky-Watcher website and perform the update following the instructions provided here.

Requirements

SynScan™ Hand Control of version 3.0 or later.
Windows 8.1 or later
An available RS-232C communication port on the PC
RS232-USB hardware converter in case of missing DB9 COM port in your laptop / PC
PC link cable that comes with the SynScan™ hand control
DC power supply with 12~14V/1A output. Power plug should be 2.1mm diameter, tip positive.

SynScan firmware update – example hardware required

Preparation for update

Create a directory called SynScan, preferably on your C:\ drive.

Visit the Support Page of the Sky-Watcher website at htt ps://www.skywatcher.com/download/software/

Download and save two files, follow with example:

Windows program: SynScan Firmware Loader, Version 3.5 – click with Download button.

SynScan V4 – webpage with loader download

you’ll save a file with name: synscan_verXXXXXX_firmware_release.zip

where XXXXXX – is a version nr

Next download Firmware: SynScan V4/V5 Hand Controller For All GO-TO Mounts, Version 4.39.21 – click on Download button

SynScan V4 – webpage with firmware download

you’ll save a file with name: synscanfirmwareloader_verXX.zip

where XX – is version nr

Connecting devices

Connect the USB-COM (RS232) adapter to the computer’s USB port.

SynScan firmware update – USB-COM adapter

Connect the male COM plug of the adapter to the female COM plug of the SynScan controller cable.

SynScan firmware update – COM connection between H.C. and laptop

Connect the RJ-11 plug of the controller’s COM cable to the RJ-11 port on the controller. Ensure that the plug is securely inserted—you should hear a distinct “click” as the plug snaps firmly into place in the controller’s socket.

SynScan V4 COM RJ-11 plugged

Connect the controller to the mount using the dedicated cable – RJ45 plug to the COM port on the mount. Ensure the cable is securely connected to both the controller and the mount for proper communication during operation.

SynScan firmware update – connected equipment

We now have the following connection setup – example:

SynScan firmware update – connected equipment

Firmware update the SynScan™ Hand Control

On the controller, simultaneously press and hold the buttons “0” and “8.” Turn on the mount’s power as shown in below photo.

The controller will emit a “beep” sound during startup and then display the message “SynScan Update Ver….” as shown in the image. The controller has now been set to firmware update mode.

This indicates that the device is ready for the next steps in the firmware update process.

SynScan V4 – firmware version 04.39.21

On your computer, run the Computer Manager and find the COM port which will be used for update. With this example it is COM5.

Check the COM port number on your system. Open Computer Management and locate the COM port.

To do this on a Windows system:

Press Win + X and select Computer Management from the menu.
In the Computer Management window, navigate to Device Manager.
Expand the section labeled Ports (COM & LPT).
Here, you will see a list of available COM ports along with their assigned numbers (e.g., COM1, COM2).

With this example it is COM5.

Computer Manager – COM port

Run the SynScanFirmwareLoader.exe software on your PC.

SynScan V4 Update – file explorer view

Once the program is launched, you should see a window SynScan Firmware Loader , make sure the “Auto-detect COM Port” checkbox has been unchecked. Set the COM port.

SynScan V4 Update – Loader program COM setup

Click the HC Version button. The program will attempt to connect to the controller and retrieve information about the hardware version, firmware, and the celestial object database. You will see the version numbers at the bottom of the Firmware Loader as shown on below picture.

If the program is unable to communicate with the controller, enable the Auto-detect COM Port option and click the HC Version button again.

SynScan V4 Update – Loader – present firmware version

If the Loader program cannot detect an available COM port, check the connection between the controller and the computer.

Click Browse to select the SynScanVXXXX.ssf file in the SynScan folder.

SynScan V4 Update – Loader – File selection

It is recommended to enable the – Enforce database update – option and then click the Update button to start the update procedure. This ensures that the entire database is refreshed during the update process, reducing the risk of any errors or omissions.

SynScan V4 Update – Loader – selected update file

The update status can be monitored under the Update and HC. Version buttons.

SynScan V4 Update – Loader – Erasing flash ROM process

SynScan V4 Update – Loader – Firmware update in progress

Update Complete.

SynScan V4 Update – Loader – Update process completed

Click on the HC. Version button and check if the controller has reported a new Firmware version.

The update was fully successful.

SynScan V4 Update – Loader – New firmware version

Close the Loader program and turn off mount power suppl.

Turn the mount’s power back on and check whether the controller displays the new firmware version.

SynScan V4 – firmware version 04.39.21

Check if the mount and H.C. works properly.

As you can see, the firmware update process for the SynScan V4 controller is not overly complicated, but it does require careful attention. It’s crucial to follow all the steps outlined in this guide in the correct sequence, with focus and precision.

I hope the description provided could be at least somewhat helpful.

It’s worth mentioning that the mount performs excellently in the field when used with the PERUN II power bank.

SynScan GOTO controller – trouble with buttons

PekDar — Sun, 13 Jul 2025 08:28:25 +0000

Even though this article has been around for ages, it still offers valuable insights and practical support for users of the SkyWatcher NEQ6Pro mounts. The content has been refreshed and tailored to match the current website engine, making sure everything looks and runs as smoothly as possible.

At some point while using the controller, I noticed that the ESC button wasn’t always working. I lived with it, but after a while, the left Ra button also started acting up and wouldn’t always connect. A red flag went up in my head – something needed to be done. It’s worth noting that the problems appeared right after the warranty period ended… coincidence?

There weren’t many options, just two: either send the controller for service and pay a considerable amount for the repair, or try to fix it myself. My tinkering nature took over (as always), and I set about solving the problem on my own.

I assumed that some dirt or substance must have gotten inside, which over time became sticky and was gripping the button. I don’t recall spilling any liquid on the controller, but I also can’t rule out a situation where rain or high humidity (fog) penetrated the controller’s interior.

My recent, not-so-great experiences with electronics, especially those manufactured in China, gave me an idea of what I might find inside, so I prepared a few things for the job.

Contact spray – quite a nice product for cleaning and degreasing electronics and optical devices, including removing contaminants from glass without damaging optical coatings.
Cotton swabs are a must-have.

IPA PLUS – contact

Plastik 70 spray – in my electronics work, I usually reach for Plastik 70 spray (clear lacquer). It creates a thin, transparent, and, most importantly, sealed coating. It excellently protects soldering points from the tin components oxidizing and forming ‘cold solder’ joints, which stop conducting electricity relatively quickly after service work.
A small, so-called artistic brush will be necessary to precisely and evenly spread the Plastik 70 over the repaired surfaces.

PLASTIK 70 – spray plastic

Let’s get to work.

We’re unscrewing the controller; it’s held together by 4 Phillips head screws.

SynScan controller – back screws

There are no clips, so slowly and gently, but without excessive force, we remove the housing. On the left side, carefully disconnect the white ribbon cable (signal) with the white plug and the plug with the colored wires (power).

SynScan controller – PCB – comm tape and power line

Grab the PCB board from the left side and slowly, gently turn it over to the right side.

Contamination is visible at the soldering points of the white ribbon cable. Below, you can see dirty pads for the ESC button. Now I know where the problem with the uneven operation came from; it would connect sometimes and sometimes it wouldn’t – irritating.

SynScan – PCB – dirty solder points and pads

It’s not that visible in the photo, but the direction button pads weren’t exactly clean either. It was quite noticeable under the light.

SynScan – PCB – dirty pads

The opposite end of the controller, was also dirty. The soldering points of the disconnected plugs. The button pads were also dirty. I’m at my wit’s end. There’s no choice, the entire PCB will have to be cleaned.

SynScan – PCB – dirty solder points

How to clean without breaking anything? Spray a little of the substance into the removed cap from the contact cleaner and dip a cotton swab in it. Lightly wipe out the dirty areas. Repeat the process until all the dirt is removed.

Once you’ve cleaned all the areas, you need to protect the soldering points. Plastik 70 and a brush will be used for this purpose. The procedure is very similar to cleaning. Spray a little of the substance into the removed cap. Use the brush to apply the Plastik 70 to the soldering points. Wait 10 minutes for the applied Plastik 70 to dry.”

View of the controller after cleaning the soldering points of the electronics, pads, and applying a protective plastic coating to the soldering points:

SynScan – PCB – solder points nad pads – cleaned and renovated

SynScan – PCB – cleaned pads

I think it turned out quite decently. In my assessment, that’s everything.

All that’s left is to reassemble the controller and test its operation. The problems that occurred earlier have disappeared.

SynScan – renovated and fully functional

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

SynScan: Manually Adding Comets and Custom Objects (User Object)

PekDar — Tue, 28 Apr 2020 11:00:08 +0000

SynScan User Object – The Database is Not Enough

The object database in SynScan hand controllers (used in Sky-Watcher NEQ6, HEQ5, EQ6-R mounts) contains thousands of entries from the Messier, NGC, and IC catalogs. However, it is helpless against dynamic objects: new comets, fast-moving asteroids, or supernovae. To point the telescope at such an object without using a computer (EQMOD), we must use the User Object function and manually input equatorial coordinates.

Step 1: Obtaining Ephemerides (J2000)

Before touching the controller, you must know the object’s current position. Comets move relative to the background stars. Yesterday’s coordinates might be useless today.

Source: Use TheSkyLive or Minor Planet Center.
Format: You need Right Ascension (RA) and Declination (Dec).
Important: Ensure the coordinates are for the J2000.0 epoch (standard for SynScan), not “JNow” (Topocentric), although for wide fields the difference might be negligible, in astrophotography it matters.

Step 2: Shortened SynScan Procedure

Power up the mount and perform the standard alignment (1, 2, or 3-Star Alignment).
In the main menu, select: Object List -> User Object.
Select New Object (or edit an existing one).
Enter the coordinates:
- RA (Right Ascension): In HH:MM:SS format.
- Dec (Declination): In DD:MM:SS format. Remember to toggle the + / - sign depending on the celestial hemisphere.
Confirm and select View Object -> Slew. The mount will point to the defined position.

Technical Limitation: Tracking

By entering an object this way, the mount treats it like a fixed star. It will track it at the sidereal rate. However, comets have their own proper motion. During long exposures (over 60-120 seconds) or with comets very close to Earth, the comet’s nucleus might appear trailed on the image, even if the stars are pinpoint sharp.

Solution: This is a “point-in-time” method. If the comet is fast, you must update the coordinates in the controller every 30-60 minutes using fresh ephemeris data.