Installing and operating a high end professional telescope…for the rest of us!


The “RiDK” 16 inch!

So you’ve finally realized your goal of owning the dream telescope! You spent years thinking about it, researching it and working towards it. You finally earned it! A King’s Ransom was spent on it and now it’s in your observatory. Yes, it’s very exciting but as you look at it sitting there and the documentation that came with it, you have this queezy sensation build in your gut. You’re looking at all of this stuff, all of the equipment, all the expense. You’re thinking maybe you’re over your head now. Shouldn’t have done it. After all, you’ve seen APODs taken with telescopes 10% of the cost of this one (NOT going to mention that fact to my wife). “What if I can’t get it to work? What if something happens and I have to send it back? What if I can’t get the support I need? What if I can’t collimate it? ”

After all “Jim…I’m not a mechanic. I’m just an old country doctor!….”

Sound familiar? If so then I hope this extended blog page, which will chronicle the installation of the OS RiDK 16 up to the first light, will help you navigate through perhaps a similar situation. One thing I have realized in this hobby is that despite all of the internet groups, you can never have enough support for stuff like this. Unfortunately, the downside to owning a telescope like this, especially a foreign one is that support can be very difficult to come by. There is always a trade off. You want superb optics, the best that money can buy, you’re going to find there are not many owners of these , especially in the larger reflector market. If you buy a foreign product you’ve added another level of complexity. Now you’re dealing with the super unkown!

And so it was at the end of June 2017, the long awaited Officina Stellare  16″ RiDK arrived! It came in a huge Ryder transport truck from El Paso. 3 guys had to deliver it with fork lifts  because it came in a wooden crate that weighed over 400 pounds! There was the first mistake. I had no idea the package would way so much! After all it wasn’t like I never used an imaging reflector before. The telescope weight was reportedly 90 pounds! That’s not even twice that of my previous Astrotech 12 inch Ritchey. However, the higher end reflectors of this type, Planewave and others typically come in these crates that weight 4-500 pounds. Because of this you need to plan accordingly. How do you get the crate up to the observatory? How do you get the telescope safely out of the crate and onto your mount?

July 13, 2017- I had a couple of friends from work drive up to Mayhill from Las Cruces with a Suburban and trailer carrying the scope. I was lucky they offered. I do have a pickup truck but the tailgate on those trucks is not rated for that much weight. Don’t go there! The transport went smoothly. We got the crate into the observatory without a problem. I checked the door width way beforehand to make sure it would pass through a while back so there were no surprises

July 15. Time to open the crate! The top of the crate has screws so that was easy. I took the lid off. There it is . Nestled between layers of styrofoam and wrapped about 10 times in plastic. You’re afraid to touch anything. I’m the person that will find a way to break something if there is a way!. *My advice is to read through the documentation several times. Don’t panic if you don’t see something you think you’re supposed to see. Don’t stress out about all of the details in the documentation. Gradually order will arise out of chaos. At this level it is unlikely there is something totally awry with respect that something is missing.

So as I look through the pages, the first is a section on “what’s in the box”. Great! Now I look at what is checked off on the packing list. I see that an item I ordered which was the ATC-02 telescope control system is not checked and there is something else there called “OS- Bus” that is checked. I look through the documentation and cannot find any reference to this at all. OSbus

The items checked off are found in one of the pelican cases that were packed separate from the scope. I look at it. To me it seems like this must be some kind of control unit but again there is no documentation for it at all. I only see one cable that connects to wherever. The ATC unit has at least 2 ports for serial cable connections. Intuitively this would make more sense because you need to integrate primary mirror temperature control, fan control, secondary mirror motor control and the mirror shutters (mirror shutters! Did I REALLY need that!). OK so this is definitely something I have to contact OS about because maybe I didn’t get what I was supposed to?

Now a word about patience. You wouldn’t be here dealing with this if you thought this whole thing was a plug and play device! I find the best approach to this is :

1) Make a list of every anticipated step you will need to make to complete this project. Make the steps as small as possible. For example “open the crate” sounds dumb but when you do that you feel like you accomplished something. Then “check the packing list” etc etc. 2) Make a list of very specific detailed questions to ask the vendor or support where you can get it.I am finding these guys get impatient if they get a sense you are clueless. They will quickly stop responding to you if you ask questions like “what do I do now” or “HELP! ” When you get answers to questions, mark those as “solved” much like you do on support forums. Make a game out of it. As you solve more questions you will gain confidence for the more difficult problems!

So I emailed OS (Officina Stellare) and they did confirm that yes the OS Bus is their new control system but “My bad, there isn’t any documentation for it yet”!! So beware the documentation you receive might not be current! Ok no problem I have solved one question and I didn’t get short changed. There is a cable that apparently connects to the back of the primary. There is a “printer style” usb cable to connect to the computer and there is a power cable that connects to 12 volt power. There is this silver thing that I discovered was a collimating wrench after looking through the documentation again. The black collar I’m not sure about but could be for centering a collimating device if it’s needed.  I look at the rest of the scope and I can find the 4 motors controlling the shutters. Nothing else unusual. Everything looks ok on the outside.

July 22. Time to mount the scope!


Believe it or not this version of the RiDK is the smallest they make! Most of the scopes they produce are so heavy that you have to lift them out of the crate with a crane! This one I felt was light enough that 3 persons could easily do it, but to do that I had to remove one additional panel. Not trivial because the panels are nailed with a million nails! I was able to remove one end using a crow bar and hammer. Not too much collateral damage and no blood thankfully. I placed some foam on the floor so when the scope was slid out it would be supported. Moving the scope to the mount was actually very easy. I enlisted the help of one of the neighborly astronomers and it literally took 2 minutes to do. Most scopes have the standard losmandy type dovetail which slides on just about any mount out there. So it easily fit on the Paramount’s versaplate with no issues. I placed it forward of center because it is definitely back heavy and will get heavier with camera equipment. (see image at the top).

I then proceeded with rough balancing of the scope. I made sure I had at least enough weight to achieve that. Those of you who have used German equatorial mounts know the process. With the RA axis horizontal to the ground there should be no movement on either the scope side or the counterweight side. The dec balancing will have to wait until the camera equipment is attached but it looks like it’s in the ballpark.

July 23. We look at the focuser – camera interface. The scope comes with this round cover that sits right inside the opening in front of 3 allen screws. You can see it in the image at the top. I look at the Rotofocus or the focuser/ rotator that is the upgrade from the manual focuser for the OS line of scopes. I did a lot of research on this and felt this unit was the best option in terms of lowest profile, best resolution. However sometimes you don’t get the full story. First of all I find out it is NOT an OS product but manufactured by a 3rd party called “Reginato”. It looks nicely machined. But I do not see a threaded interface in the opening. The mounting portion has 6 pointed allen screws?! I contact OS. The sales guy says this at first: “Hi Dave, my suggestion is to use a threatened adapter. Probably the screws will hold your imaging traing, but flexure or sliding…I’m afraid for them”. Hello. There are no threads in there! I didn’t think it would be too hard to find someone who could verify this attachment but the OS user group which is a Google group is mostly dead. I did get a couple of responses to presales questions but since then I have seen ZERO activity on that group. Hmmm. Well like I said, we are in uncharted waters for sure.

Ok so now what? I got this adaptor from OPT (Optcorp, the California distributor for just about every telescope and accessory in the world. I have been a customer of theirs for years. I think they generally do a decent job). I am looking at it and sure enough I don’t see any threads on there either!OSadaptor

I see the screws to mount to the AOX on the camera side. Ok that looks fine but the Rotofocus end is as smooth as a baby’s you-know-what. I contact OPT and ask them what the deal is with the adaptor that they had machined by Precise Parts? Why isn’t it a threaded interface? Isn’t that what it’s supposed to be. They say they requested the actual drawing from the engineer at OS and sent that to Precise Parts to make the adaptor. OPT sends me the drawing and I send it to the OS rep. To me it certainly looks like there are no threads. OS-rotofoc3-nosepiece

Finally the same OS rep responds after looking at the drawing with: “Well, Rotofoc is produced by Reginato and not from us..we personally LOVE to screw everything “(ha ha ha very funny)”…we personally use rotofoc with heavy imaging trains: atlas proline 16803, fli FW, giant flip mirror and so on.. ” Ok then. Well that’s interesting. The sales people at OS do not even know that the Rotofocus does not have threads!! However we have solved another issue, that being the telescope/ camera adaptor is correct for better or for worse. We will certainly be testing it out with the weight we are planning to put on there!

So far then we have the telescope mounted, the rotofocus adaptor confirmed as being correct, the control system is correct. Now as you go through these steps and things like the issue with the unthreaded focuser interface pop up unexpectedly there is this tendency to allow resentment and judgment creep into your head. Don’t allow it! Keep your mind open to everything and attached to nothing. Sure, I could have just put a freaking nitecrawler on there and avoided all this nonsense but guess paid close to 4k for this upgrade! You own it!

July 24. Examination of the Rotofocus accessories confirms there is a power cable that has a European 2 prong AC adaptor. The OS bus will have to be connected to a 12 volt power source so I have decided to do the same for the focuser. The European to US converters I think will be too risky and unreliable. Additionally I wanted the cable situation on this new platform to be clean with no snags. Having a long AC power cord will just wrap around the telescope every time it slews. I contacted the OS engineer and he did confirm that you can do that. Ron at Moonlite Telescope Accessories, long time manufacturer of high end US focusers, whom I have worked with for over 10 years, confirms that you can cut off the adaptor end and plug in the 2 wires to the 12 volt accessory.

We go ahead and attach the Rotofocus to the telescope. Ok that was easy! Just loosen the 3 allen screws and the flange fits right in there.

RiDK5Interestingly when I open the cover of the focuser end of the scope I am startled at first to see this elaborate glass enclosure and I am reminded that is the corrector lens. I see a perfect image of my face in there! Hmmm. Interesting.

The Rotofocus cannot be operated manually and the interface is totally racked in all the way so I can’t access the set screws. Looks like  I cannot attach the camera until the unit can be powered up. So we install the control software for the focuser. That is pretty straightforward although the documentation is very confusing. There is something about plugging in the device during the installation, not afterward and nothing about having the device on or not on. So I rely on my reasonable experience with all kinds of camera and focusing equipment which in 100% of the time you install the drivers FIRST before plugging in the device. That’s what we do. The focuser is controlled in 3 possible ways, just like others. You can use a proprietary software to operate the focuser manually from a PC, you can control remotely with ASCOM (which is probably what we are going to do eventually, although there is a native driver in The Sky X program which might also work) or you can operate it from a control panel connected to the focuser. Since we do not have power yet that will have to wait. However it appears the software was successfully installed:


Ok, it’s in Italian. I thought I checked off the English option during the install! No matter. It’s pretty obvious I think what the icons and headers mean!

The final issue with Rotofocus is that there are 4 ports visible. There is one for PC connect, one for control panel connect, one for power and one apparently for a temperature probe which I did not receive. Apparently these do not come standard and cost about 70 bucks or so, just an FYI. They come standard on US products. However I have a couple of extra probes lying around from other focusers that I can try.

So at this point it looks like the next step is going to be power. I have created another page for that entitled “Setting up DC power for the RiDK platform”

August 5. The moment of truth arrives. The last 2 weeks I have been researching the 12 volt power system. Everything was prepared for. I tested the connections over and over. The Rigrunner was installed and tested. I confirmed with OS the central plug on the adaptor is positive. The voltage reads 14.1 positive coming out of the plug. I connect all the usb cords. The one going to the PC has an adaptor. Interestingly the usb plug is recognized by the PC and it tells me “driver was successfully installed”. Ok maybe a good sign for the software later on but now we need operational hardware. Finally I turn on the power transformer, again measure the terminal voltage to 14.1 and plug into the focuser and………..nothing! Are you kidding me? Zero. I checked the software and unable to connect. I checked the handpad and nothing. Can’t explain it. Could I have reversed polarity on the leads accidentally? Not likely. The power was read as positive coming from the center. The voltage was well within the range of the manufacturers specs. Time to go back to the emails and forums! That is a sinking feeling for sure but we’re not giving up. We still had one item left to try and that was the telescope control system. If the rigrunner is powered properly and we are measuring things with the multimeter properly then this HAS to work or something is seriously wrong. Ok then. We removed the focuser input to the rigrunner and replaced it with the power cord from the OS Bus. This power cord was sort of a no brainer as there were already 2 leads, one red and one black except the red lead had this bizarre break in it with 2 ends brought into contact with a spring loaded mechanism. I tested continuity of that connection and it appeared that there was none! Cmon! Can I not get a single break on this thing! Ok so what I did was pull the springs away and just taped the contacts together, then tested that and it seemed to work.


What could possibly be the advantage of a split wire like this! Here is the tape job we did hopefully just temporary to get it to work

Onward and upward but we need to ask OS about that because I would prefer to get rid of it if it’s unnecessary. I again tested the voltage coming out of the end before connecting to the OS control box. 14.1 volts. At least the output is consistent! I connect the usb cord to the computer but first I install the Bus control software. That goes fine. They explain the steps there clearly. There is a 4 prong connector that goes from the control box to the back of the telescope. Ok that was easy! Finally I plug in the power cord. At least there is a switch on this thing. I turn on the switch and………the sweet humming sound of mirror fans fills the air! Amazing! It works! Now I go to the computer, access the OS control software and everything is there. The fans, the mirror shutters, heater and secondary motor but there are so many tabs and features my head is spinning and there is no documentation! Thankfully I have enough experience with software I can at least confirm that the basic functions work. Each of 3 fans can be controlled separately as can each of the 4 shutters. There is environmental monitoring, pressure, temperature and humidity. Ok that’s what I’m talking about! So at least the control system is operational!


The failed connection from the focuser to the Rigrunner


Success! The OS bus is connected and powered up. I just used heavy duty velcro strips to hold the control box on the scope


No, we’re not inside a nuclear submarine. This is just the “main page” of the OS telescope control system! It shows status of mirror shutters, fan speeds and I believe the motors on the right are for the secondary

Finally, you can see the mirror shutters in operation in this video

So at this point we have:

  1. Operational D/C power supply for at least the telescope control system
  2. OS Bus system is confirmed operational for at least the basics, mirror shutter and fan. Software appears to work fine although there are a ton of features we have no clue on.
  3. The Rotofocus for now is dead on arrival. No clue on why it does not power up.

Obviously the key now is to troubleshoot the focuser problem because we cannot go any further until that works

August 7. Looks like there are features that are similar from the older ATC-02 control system that are documented in the manual they did send so we do have that. Once everything is operational We can spend more time going through it.

Unfortunately no one seems to be around because OS is on vacation until the 21st! Life is good I guess. I don’t know. Maybe we are too stressed out here in the US. Not sure I have the patience I thought I did. 2 weeks with no customer support! That’s absurd. I contacted Ron at Moonlite and he gets back to me right away. No problem manufacturing a flange for the scope to accept a Nitecrawler. He is going to need the backplate from the scope so he can machine the parts exactly. Do I want to take a chance it gets lost in the mail? With my luck it’s sure to happen. Unfortunately I will not have the funds until October. I did have another Nitecrawler in the budget anyway but that wasn’t to take effect for at least a year and a half. Looks like I am going to move that up. Just to see what my options are if I can cut my losses I would consider returning the Rotofocus. I emailed OPT. Doubtful they will accept because it’s a custom order and I altered the adaptor. No matter. I will slog through it if necessary but I’m telling you right now I think I screwed up with that decision. Pins and not screw fixation plus hardware support is totally zero. I cannot even find a company website or anything belonging to a ‘Reginato’.

August 8. One more trip up to the observatory before we leave for “Eclipse week”. I did hear from OPT. They say they will contact OS to make sure they support the Rotofocus. No matter. I went up to Orion’s Belt fully expecting to remove the back plate and send it to Moonlite. I did however ask my wife to check the hardware stores for an AC converter thinking I would try one last ditch effort to see if the focuser was in fact dead metal or not. She was not able to find one anywhere but wait, my daughter used one a couple of years ago for a European exchange student!


AC converter for the European style adaptor we found!

Well what the heck. I figured why not put a couple of power pole connectors on the other end of the adaptor plug I cut off before and reconnect to the focuser end basically restoring the original AC adaptor cord. Didn’t see why that couldn’t work. If it still didn’t power up, then I guess we’re done with Rotofocus. So that’s what I did


Original adaptor end I cut off with the power pole connectors applied. I just matched the wires up. One had the dashed lines on it and one did not so it was pretty easy


Here is the restored adaptor plug with the connectors

So here we go. I plug in the restored AC adaptor plug with the converter we found and PRESTO! The hand pad suddenly lights up! The whole thing is in Italian but I basically play around with it for awhile and determine that the much maligned Rotofocus is indeed operational! Incredible! I experiment with the move in and out functions and yes it does work!


Newly powered up handpad for the focuser!

Next we see if the software works. I open the program and “no connecti”. Hmmm. We know the drivers were installed correctly, plus when you plug in the usb it makes that 2-tone sound indicating the device is recognized. I made sure the USB adaptor they sent was oriented properly. Then I remembered, “Aha! when this kind of thing happens it usually means the COM port is not assigned”. I look in the program menu items and there is this icon with tools on it. I click on that.


The “tool” icon apparently was the correct one! It enables access to the control panel where you can set your COM port. Note the language is mixed Italian and English!

We set the COM port to 6 and then click on connect and sure enough a connection is established!  So now we have a powered operational focuser we can operate with the handpad and the PC software. I have the documentation for the software so we just have to look at that. I did experiment with the homing buttons and that seems to work also!


Focuser connection successfully established indicated by the green position tabs!

So the question now is why weren’t we able to power up the focuser with the Rigrunner? I disconnected the power from the focuser, leaving the AC adaptor plugged into the wall socket and decided to measure the output voltage at the adaptor plug (the one that plugs into the focuser) . I put the red lead from the voltmeter into the center of the plug where it’s supposed to be positive and black on the side. I read the meter. It reads MINUS 11.4 Volts! They apparently gave me the WRONG polarity info on the plug! I guess I am very lucky the device was not damaged, but that is totally on them. So I went to the Rigrunner and reversed the leads going into the adaptor plug on the focuser, turned on the transformer and sure enough, the focuser powers up! This leads me to the following conclusions:

  1. NEVER set up your wire polarity until you have explicit documentation in writing from the manufacturer, NOT word of mouth from a third party, what the plug polarity is supposed to be!
  2. The BEST way to test the polarity of the wires in your adaptor is to first plug it into a power source, THEN measure the voltage at the adaptor plug that goes into your device . After that you can cut off the AC adaptor end so you can attach the wires to your favorite DC power source. Most of the devices such as cameras etc come with either one of those cigarette type plugs or an AC adaptor. It is best to plug that in and measure the voltage as mentioned. Sure, you CAN determine which wires go with what part of the plug using the methods discussed on this page but this may not be fullproof as I have just discovered!

Anyway, miracles do happen and amazingly enough we are a lot closer to first light than we thought we would be at this point! Next up:

  1. Attach the camera
  2. Final weights and balancing
  3. USB hub
  4. Slew testing and final cable adjustments
  5. Collimation

August 26, 2017

We’re about 2 months into this and finally getting closer to actually getting an image out of this thing! I proceeded to attach the camera to the focuser. The 6 allen screws were tightened down. I went until there was a slight bend in the wrench. Without any documentation on this we don’t really know how tight to make the screws but just went with experience. The jury is still out on this thing in terms of how much the flex in this connection will affect things like collimation etc. However it does seem to hold at least for now. I had to try a couple of times to get the adaptor as flush against the focuser as I could.

After attaching the camera the counterweights were adjusted to balance the RA axis. As it turns out I did not need additional weight. There is a total of 140 pounds on there now. Next the powered usb hub was installed. I was able to connect both the focuser and the telescope control to this hub and it works very well. I velcroed the hub onto the telsecope. Disaster was barely averted when I was testing the focuser and the power cable from the OS bus got caught in it! I swear you can’t make this stuff up! I was able to pull it out and no damage was done to the focuser except the cable housing was scored slightly exposing the wire so I just covered it with electrical tape. Interestingly I did figure out how to change the language in the focuser program to English!

Final step was cable management and slew testing. The cable situation is a major problem but I was able to clean things up reasonably well using a lot of cable ties to the holes in the telescope frame. So that’s what the holes are for! Unfortunately I think there is only so much you can do in the case of equipment like this in a permanent set up. The USB hub is AC powered as is the DC transformer and the camera. I am not about to try and power this camera with all the accessories on it using a D/C power source. At least not now. The USB hub is also AC powered and that can’t be changed unless you purchase a D/C powered unit. The D/C transformer that powers the Rigrunner has to sit on the floor. So the only things coming off the scope are the power cord from the camera, the power cord from the USB hub, the D/C power cord from the transformer and the ethernet cable that connects to the USB hub. In the future we can try to tweak that but for now I think it’s OK. We then proceeded with slew testing which seems to work fine with the current setup. No stalls and no cable snags. I went back and forth from one side of the meridian to the other several times. Seems to be fine.


Camera is attached to the focuser


USB hub is attached to the side of the telescope.


Not sure we need this but the handpad to the focuser is attached to the side of the mounting plate


All the operating components are now in position. ‘A’ is the USB hub. ‘B’ is the focuser. ‘C’ is the camera. The OS bus controller is on the other side of the scope. Cables are secured to the holes in the telescope frame with cable ties


Final configuration with the scope in its parked position. On the left you can see the camera power cord coming down and joining the other AC devices and the D/C power cord. They are not dragging on the floor but lie close to it. The telescope can slew with no cord impingement

Next up is the optical portion of the set up! Collimation, pointing model, focusing etc.


September 1, 2017-

Deployment Day! After all it’s all about the optics. That’s what you spend the money on. Finally we are ready for night time operation! First item is we need to see how far off we are from collimation and focus. We need to take an image! Ok so we turn on all the equipment we worked on for the last several weeks. Now the documentation originally supplied is somewhat useful. We turn on the fans to 100% with the control system. Open the shutters. Still somewhat quirky. I had to reboot the software like last time to get them all to open. Not sure what is going on there, but they do open. So now we did do our slew test last time so I slew to around 60 or 70 degrees altitude south. The moon is waxing, now gibbous phase so it’s not dark but for this phase of operation it’s fine. In the documentation for the ATC-02 system, the “old version” there is a point about setting the secondary to default position. There is a check box which I do not see on my screen anywhere. Here we go again! All I find is a homing button for the secondary so I try that. Not sure if it is doing anything. No matter. We have the camera turned on and I did confirm all of the camera equipment was operational before so we’re good on that.Finally we take out first image ever with this new system!


First ever image taken with new set up!

So while we are not in focus, the defocused star images are round throughout. I see no obvious deformities. Great! We are finally getting somewhere!

Next we rack out the focuser until near focus is reached.


Near focus is reached somewhere in the middle of the travel. A couple of sensor column defects. It happens but they easily process out

Near focus is reached somewhere in the middle of the focus travel. That is also great news as we will need to do autofocus runs and you need a decent amount of travel on both sides of focus. As you can see the camera has a couple of column defects in the sensor which does happen with the class 2 sensors but these can be processed out.

So 2 critically important questions have been answered. Can we reach focus? Yes we can fairly easily and position looks to be about right so we have enough front and back for automation. Is collimation close? Hard to say for sure but experience tells me if things look round all the way side to side I think we are close enough we can use the software to collimate like we usually do. We do need to find out about the secondary position how to set that if we need to because that will change the backfocus. Otherwise we can now proceed with collimating. First we need to get a decent pointing model for the scope. The pointing accuracy looks pretty good after a preliminary run. Once we can get good pointing so we can center stars we will be able to accurately collimate.


The 16 is powered up with covers off, ready to work!

September 4, 2017

The final critical step before we can start imaging is collimation. Thankfully I do have experience with this. My traditional go to method has been collimating in the field with the camera mounted and a software program called CCD Inspector ( This has been fullproof for a number of scopes including my previous RC’s and newtonians. However to do this I needed to be sure we were close to the mark. Preliminary results from the last outing suggests we are. CCDI records the collimation error in arc sec. Experience has shown that under 5 arc sec is good. Beyond that you are probably seeing limited. So here we go!

  1. Step one is to confirm you can center a star consistently and reliably. To do this you need decent pointing capability. With a camera connected you are going to be pulling your hair out if you need to keep using a handpad to center your star. So for my set up I am using The Sky X as my camera program and planetarium program. There is a feature called “closed loop slew” where you can slew to a star and the program will plate solve and center it. This requires pretty good pointing and entering your image scale accurately so the plate solves will work.

    Star is centered to begin the process. The live collimation viewer is seen on the left. The number is in arc sec

    2) Defocus the star. We rack the focuser all the way out. Make sure the defocused image is at least around 200 pixel diameter . This step took the longest. You have to find a star not too bright or dim that the software can register. Once you get consistent readings you are good. Then take exposures and see what the software tells you the error is. Initially it was around 6-7 arc sec. That’s pretty good right out of the box!


    Live collimation viewer shows the collimation error to be around 6-7 arc sec. The arrow points in the direction you need to move the star image

    3) Next we turn one of 3 collimation screws. The documentation on this was very clear. On my scope there are 3 collimation screws similar to what you would see on many reflectors. It did not take long to tell which screw moved the star in which direction. These are very easy to use. You need to move the star image in the direction of the arrow


    Star image is moved in the direction of the arrow

    4) Recenter the star and repeat the process


    Getting better! We are now in the 1.5 to 2.5 range


    I think we’ll stop here! After a few iterations of this the arrow starts to flip around and does not stay in the same direction. You start to become limited by seeing. But we are definitely lower than 5!

    So congratulations! We survived the installation process for the most part and we have a collimated telescope we can start imaging with. While there is way more to do, we are a lot closer now to an actual imaging project. I would say looking back the biggest issue is still the focuser and the jury is still out on whether that is going to work during automated sessions. We did have a couple of malfunctions during collimation where the homing sensor failed and I could not move the focuser. Unfortunately we will have to see on that once we start automated focusing. I think the optical quality I am seeing so far seems to be worth the expense! The field is definitely flat to the corners. This was probably the easiest collimation I have seen on any reflector! I have not officially rated the telescope yet. I think I will wait until I actually start imaging. I think the support in general for this system is spotty at best and poor for the Rotofocus. That is the weakest link in the system. There is no hardware documentation at all for Rotofocus and I received minimal assistance with the installation. I had to basically shoot from the hip until it worked, and there are still issues to be worked out, but again, the final test is still to come. Tonight I will actually try the ASCOM function on the focuser and see if it can accurately autofocus.

Sept 25. First light is achieved! Hard to believe folks we finally did it! We fought through the set up and battled until we finally got it done! So we did test the focuser and it works fine however the Focus Max V curve is not as crisp as it was with the Moonlite but we are operating at much greater focal length. We discovered that there is a backlash setting on the Rotofocus that Reginato recommends we set and this is based on bench testing. We did that and not sure if it made any difference or not. We also learned the ASCOM driver for Rotofocus is read in steps and not in actual micrometers. This is expected.


Focusmax V curve. Position is read in number of steps at 0.1 micron per step

At any rate we are learning also that seeing has to be better than good at this focal length or the stars will be soft. An HFD (half flux diameter) of between 5.5 and 7 or so is expected for this focal length of 2800mm. We picked the Cocoon nebula (see blog post for 9/29) as the test target. 10 minutes luminance with AOX guiding. Here is the result:


“Cocoon” nebula. An emission/ reflection nebula in Cygnus. First light for RiDK!


So I did give the RiDK 5 stars. The star images are superb! And this was in marginally average seeing! Onward and upward!

That’s it for my trials and tribulations on the RiDK 16 set up and installation. Hope someone out there finds it useful! Feel free to email me with any questions.

Dr Dave

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