Astrophotography is possible with a Dobsonian and equatorial platform!
I’d been frustrated by the lack of ability for my Zhumell Z10 10″ Dobsonian reflector telescope to track the night sky. After MUCH research, I found that the cheapest way for me to get basic (and automatic) sidereal tracking is to build (or buy) a motorized equatorial platform, which required absolutely no modification to my Dobsonian telescope. The best part about it all is that it WORKS! Just point it to the celestial pole (north or south), level it, sit the scope on top, turn on the motor. Done. Here is my build, in pictures.
Oh, so you need proof? Well, in late 2012 I started with astrophotography with this setup, and these are a few of the shots I managed to get with it — some of my first astrophotography, ever! It’s by all means not a wonderful example of AP, but at the time, it was amazing to me!
You can also download my old SketchUp plans right here, if you want. It might give you an idea of what I was getting at!
I see your EQ platform is different to others I have found online. Any chance of some construction details? Cheers.
Sure! What exactly would you like to know? I’ve since sold this telescope and the platform with it, but I remember the details of how I built it.
That looks great indeed. Would you have all the details, like, dimensions, angels , material used, motor used etc. I know since you’ve sold it, you may not remember, but once again this looks simple enough and possibly one of the best designs out there.
I’m an beginner, this is only my second telescope (awaiting shipment). I earlier had used a cheap 120mm telescope and remember how frustrating it was to watch the object float out of the view, but buying a motorized company manufactured telescope would be very expensive indeed.
Hi Gaurav! Thanks! It was a fun build.
I remember most of the materials I used. The dimensions not so much, because you have to build it somewhat based on your latitude. I’ll update the post in the next few days with some more detail from what I can remember.
If you have the building skills and tools, it can be very cheap, but, I can tell you it is also worth it to move on to a proper motorized mount!
Sorry for the delay in replying. New house, big section and I have my work cut out. I have to admit the Gaurav has asked all my questions except did you use an online spreadsheet? I do appreciate your comment about using a “proper” EQ mount but the platform is suitable for my purposes. My wife and I expect to run public nights on behalf of the local astronomical society and a platform will be easy to transport, set up and use. Cheers.
No worries, Mike.
I looked at some of the spreadsheets, but in the end did not use them. I instead created a 3D model using SketchUp to find the exact angles I needed (the image of the cone), and then used that to create a template to print out and use when building the curved guides.
Yes, for your purposes an EQ platform would be great! More bang for the buck. It’s pretty much throw-and-go, especially for visual use.
Like I said — it’s on my list to update this post with all the details I can remember, soon.
I am intrigued by what you used as the rear pivot bearing.
Hi Mike — that is just a large fender washer that makes contact with a large roller ball transfer mounted bearing.
I’d also love to get some directions on how to build one of these ( I’m having a very hard time finding clean directions online, there are lots but they are messy and hard to understand ), I like that you used the Celestron motor drive, as many of the designs I found use a complicated DIY motor system I just don’t want to take on.
This design looks quite simple and clean and I think I could figure it out as long as I knew how you used sketchup to figure out the angles on the curved track portion, and the length to the rear pivot bearing. But I don’t know for sure because I think the calculations are a bit trickier than that.
I’d very much like to take this project on, and I like your design.
Did it work good when you had it?
I’m glad I’m not the only one having difficulty deciding which variant of an EQ platform to go with. I have pretty much decided that a vertical north/south sector has to be easier to set up (half the number of roller bearings to start with) and a pivot for the rear south/north sector (another less complicated item to make). However, while there are plenty of constructed examples, there seems to be little on how to design them. Messy is an understatement.
Messy is definitely an understatement. I’ve looked through dozens of pages and still don’t have a clear image of the whole construction on these things… Mind you I’ve been specifically looking for a model that uses a Celestron motor drive, because like I mentioned, like 3/4 of the designs I found have a goofy DIY project for the motor, with a few parts from John Doe’s website, and Joe Blows hardware store….
Hi Andrew and Mike, apologies for the delay!
You guys are having the same problems I did — lots of “designs,” but not a lot of good instructions for the build. It took me a long time to figure out exactly how they really worked and then come up with my own simplified design for it.
Believe it or not, it actually tracked really well, especially being made out of wood, with a heavy telescope on it, and just the inexpensive little Celestron motor drive. I was able to able to do some pretty good DSO work (fast scope, f/5 newt), and it helped immensely with planetary. I was successfully tracking and shooting Jupiter and Saturn at ~4,800mm (two 2x Barlow lenses on my DSLR). I have some raw video on Youtube with an example, I will link to that as well.
I apologize I haven’t had a chance the last week to update my article with more details, but I PROMISE I will soon! I have recently found some of the images I created using the setup you see above, and I even found the original SketchUp file I will post for download. Hopefully using that, you will be able to see how I created and designed the curved vertical sections, and the angles and such.
I apologize for the delay (again…) but I quickly updated the article with a download link to the old SketchUp plans I used, and the template I created for the roller guides. It might help a little as well.
Hope it helps!
Also, how well does it actually track?
I’ve got a 8″ skywatcher dobsonian, and I’d like to at least make use of my digital cameras small 15 second exposure time to maybe take a few good images of say the greater orions nebula to stack into something worth while.
As I replied above — it actually tracked quite well. I was able to do some pretty good DSO work at 1200mm f/5 (the scope above, same setup, up to 45-60 second exposures at times), and it was great for extremely-high magnification lunar and planetary.
My problem is that I think too much about the best way to do something. I need to stop. I haven’t done anything for a while as the new house and grounds have taken up most of my free time. However this also is about to stop for a while. Scope comes out of the box in the next couple of days, it will need collimation. Then back to the EQ platform. Cheers.
Great article. Could you post a complete parts list required for us to build our own versions of this mount?
It’s on my LONG list of things to do, so yes…eventually! It will have to be a somewhat vague list in the end, and some DIY creativity will have to be used on your part, but I can give some details as soon as I make time to do so!
Greetings from shiny Greece. We need your list…
It’s coming…! 🙂
This is an excellent design and much cleaner than most plans I’ve seen out there. I would really like to know how you determine the curve on the two top pieces of wood on the T. I built one of these but the object I’m looking at tends to drift upward in the eyepiece. Obviously my angle on it is too high, the scope points down quickly.
Thanks, I wanted to simplify things as much as I could while still getting decent performance. I used SketchUp to help determine to angle for my approximate latitude and the curve (the first two photos), and then further refined the design using a hinged jig I built to rotate around the axis with a clamped sander (the last four photos).
Why do you have a bolt through bottom and top of the platform?
It feels counter to the movement of the tilting of the platform?
Good catch! Actually, that bolt is simply for transport purposes. I bolt the top and the bottom of the platform together so when I carried it around the two pieces didn’t fall apart. 🙂
Of course! I like the simplicity of your design would you please explain
Why did you use the jig when you have already printed the form of your VNS bearings ( I have a copy from reinervogel.net so ready to go)
With the single pivot bearing on the south end is the angle of that mounting critical or do I just need to make sure that the table top is level?
Was the commercial motor upto the job? ( or do i need some gears etc)
I used the jig to further refine the curve because my printed VNS shape wasn’t quite perfect enough for me after a while. The jig does it much better.
I don’t believe the angle of the pivot is critical, but the height vs. the front bearing is. Keeping things level is always helpful! Better safe than sorry.
The motor handled things without a problem, but I did run into an issue with the battery not lasting long enough, so I created an external power source to keep everything stable.
I’m by no means a pro at this, because it was my first and only platform I built. However, I put a lot of time into tweaking it. 🙂
Good luck! It was awesome to use. Nothing like viewing or shooting Jupiter and Saturn with a 4x Barlow and not seeing drift in the eyepiece. 🙂
Great build. I’m a bit late to the party here but just finished building one of my own and am using the same motor. I noticed in your last post you mentioned you rewired to a better power supply. Do you recall any details of what you used?
No problem — the power supply I used was simple: I just purchased a cheap adjustable power supply (that had 9V as an option), cut the wire and replaced it with a stand 9V battery connector. A cheap and easy way to take the place of the 9V battery that didn’t last very long with that kind of load!
Hi Cory. Was searching on how to make a EQ platform and just found this blog. Nice job you made there man! really simple design.
I have another question regarding the Motor Drive.. How did you manage the speed, to keep the objects centered all the time?.. Does that EQ drive have a speed regulator?
I´m currently in plans on building a EQ platform for a 17.5 incher Truss dob i made, and i´m looking at Orion´s EQ2 Drive and wondwring if it can do the job:
Thanks! The motor drive has a little knob on it for speed control so I could get it set up perfectly. Of course, being a DC motor, it wasn’t as accurate as a stepper motor would be, so it required some tweaking from time to time.
From looking at that motor, it looks like it could work nicely, actually. It’s similar to what I used.
This is the motor drive I used, specifically:
Good luck with your project!
Nice post, Cory.
Only a few questions:
What material did you use for the strips in the north sectors contact surface?
How do you make the motor shaft? It seems is made of several parts.
Thanks in advance
Thanks for the question! In order to keep things lightweight and solid/smooth for the bearings to roll on, I used thin aluminum sheet metal. At first it was a little too slick for the bearing, but after I lightly sanded it to rough it up slightly things worked well. I suppose putting a hard rubber bushing around the motor axle would also have worked well!
As for the motor shaft, I used a machine screw, bolts, and bushings to create a cheap and dirty bearing that would support the weight so the motor itself wouldn’t have to because it’s so small. Basically, you want the shaft to be able to spin freely in the bushings so adding the motor is the easy part. I was determined to just use pieces and parts around my garage for this, so I am sure there is a much better way to make it. However, something to note is that a different size roller bearing that makes contact with the sector surface will require different motor speeds to accurately track. That is math I don’t want to do now! However, it can be noted that the motor shaft bearing diameter was somewhere in the vicinity of 2cm or so.
You mention the back height is important. I am about 36 latitude. Does that change the curve of the front pieces or just affect the height of the back and how would I figure them? The base of me scope is 24 inches square.
Yes — the back height is important, but it wouldn’t change the curve — that is just to help you aim the axis at the celestial pole.
I used SketchUp to create a 3D model of the cone and printed out a template from there. You can get my SketchUp plans above, if you like. It might give you a better idea of what I visualized!
I’m looking at your Sketchup drawings and measured the angle of the cones at about 41 degrees. Is that the latitude you designed your platform for?
Indeed it is! I was living in Central Iowa, USA, at the time, about 41 degrees north.
Nice work. 🙂
Thanks for the quick reply.
One more question: It looks like the angle of the VNS segments is about 14 degrees (the Beta angle referred to on Reiner Vogel’s website http://www.reinervogel.net/index_e.html). How did you determine this angle? I see on the Vogel website that Beta is chose to be 20 degrees.
Sorry to ask you to have to rummage through the cobwebs of your memory.
The page with the alpha and beta angle references is on this page:
You know, I didn’t actually measure that. I decided to all the 3D plans to make those decisions for me…if I remember correctly. I wanted it to work together in 3D around the pivot points and didn’t really worry about those other details. Using the bearing at the rear for the rotation point allowed for a bit of forgiveness, I suppose!
I just built my version of based on Cory’s design. It was a lot of fun to put together, and was made immensely easier owing to the simple, elegant and economical design. I followed the pictures closely, and relied heavily on Cory’s SketchUp drawings to better understand the concept and get the angles and dimensions.
I adapted the VNS segment to my latitude (43 degrees vs. Cory’s 41 degree design) by stretching the height accordingly.
The whole thing cost less than $100, including the $37 Celestron drive.
I have an 8 inch Orion Dobsonian, and expect I can get about +/- 6 degrees of motion from the platform. That should give about 48 minutes of viewing. I haven’t tested it out yet (it’s been a long, cloudy spell), but hope to soon and will report back on its performance.
Here are a bunch of photos of my design:
Excellent stuff. However I’m still at a bit of a loss as to how to design the vertical segments. I do not have Sketchup, which never seemed to work for me in the past. Good skills however.
Belay that. I just figured a way of designing the sectors. Cheers.
WOW Paul! That’s awesome work!
I’m very curious to find out how well it works. I know others have used my modification of the other designs out there, but I haven’t seen one that looks so similar and has some really nice improvements. One thing I didn’t mention that I thought was very important, was that I used 2-3 coats of clear polyurethane (the water-based kind) on the entire wood surface, because I didn’t want ANY warping of the wood due to all the moisture in the air from being outside. Any warping would alter the tracking accuracy…
Please keep me informed on how it performs!
Hi Paul, your platform is really nice. In addition to the many accurate photos of the work done, wouldn’t you also have drawings with the dimensions to be able to replicate the table? Thank you
Paul, I just completed my own platform based on a different design. It works great but I want to get rid of custom made 4:1 reducer after the Celestron drive. How can you drive your platform with a 3/4’’ (approx) rubber bushing? I calculate a required 3/8’’ bushing is needed. You must be running the drive very slowly. Doesn’t that affect tracking? Thank for you help.
Paul, I think I replied the wrong person before ;-(. Here’s my question: I just completed my own platform based on a different design. It works great but I want to get rid of custom made 4:1 reducer after the Celestron drive. How can you drive your platform with a 3/4’’ (approx) rubber bushing? I calculate a required 3/8’’ bushing is needed. You must be running the drive very slowly. Doesn’t that affect tracking? Thank for you help. Stephane from Quebec.
WOW! great build! I just bought a zhumell 8″ dob that I want to convert to a fork EQ mount. I already have a 114/900 celestron on a eq1 mount w/motor drive (just like yours). I noticed that yours is friction driven with the motor drive! does it track easily w/no slip? I’ve been trying to figure out a way to drive mine. lazy susan, gear fly wheels, reducer gears, worm gear drives… How did you know the speed of the motor mount would accurately track your custom size mount? Thanks!
It was fun, back in the day! I roughed up the aluminum on the sectors just to be safe, but yes, it tracked without slip. As far as the speed is concerned, I didn’t really know other than trusting the other plans I’d looked at that used that motor. Of course the size of the gearing (if you have it) and the motor axle/drum that makes contact with the sectors makes a difference as well. Being able to adjust the speed of the motor was very useful and required for adjusting the tracking. Also, since it is a DC motor, I found that it was better to power it with 9V mains power when possible, because when the battery starts to drop, it slows down.
While I think this is a great idea, it seems that in the end, it is not entirely worth it. The author states that he has since sold this setup and even recommends that one should gravitate towards a real EQ mount for any serious AP work. Nevertheless, this is still a cool project!
Cory, that’s fine work finely presented – the pictures are great. I’ve just stumbled onto eq platforms in the last few days – I’ve preciously thought about trying to build an equatorial mount for my Dob, but was thinking of a “full” mount, that would let the scope rotate through a full 360 degrees. It’s a large-ish scope (14″), so that was immediately an intimidating project. The platform approach turns it back into something much more tractable.
I’m an engineer, so I’m used to using math to get at problems – after a couple of days of thinking about these things I realized that the goal was to keep three points on the surface of a cone with it’s axis aimed at the pole. That made things a lot easier to picture mentally. Then I found your site, and guess what? You started out with pictures of cones. First site I saw that noted that aspect of things.
Right now I’m just trying to decide how low profile I can keep this thing – I’d like to add as little height to the already high eyepiece.
Thanks very much for putting together such an informative site! I hope you and yours are doing well and enjoying the holiday season!
For the motor drive looks like you just inserted your threaded axle into the rubbery motor drive mounting, using the screw on the motor drive mounting to tighten it in place. Did you have to drill out a hole or groove a surface on the threaded axle for the screw to stay in place while driving the axle? Or does it stay put if you tighten it enough?
Great post by the way. Currently I am trying to build my own EQ platform, your post is very helpful.
Lawrence from West Coast Canada
I actually filed down one side of the threaded axle just a bit to provide a flat surface for the screw in the axle mount to butt up against.
All the best! Post a photo of your platform when you’re finished!
HI Cory , what camera have you used please and how did you attach to the telescope/focuser ? using a 2 inch adapter ? Were you able to achieve focus since this is a trouble with dobsonians and cameras in general?
thanks a lot
Odd that I had this question twice today! I ended up using a coma corrector for Newts, which gives you just a bit more out-focus, and only 0.1x or so magnification. See here for some expanded answers: https://www.photographingspace.com/askps-dob-ap/
I used a Canon 550D, prime focus, with the 2″ coma corrector.
Do you have the CG measurements for your Zhumell 10” Dobsonian? I have a 10” Zhumell and would like to make a eq platform for my scope. If you still have your measurements it will help me verify the values that I use in various eq platform spreadsheets.
Thanks for the question, but I’m sorry to say I do not have the measurements anymore. I’ve put pretty much everything I had regarding my EQ platform on this post. All the best with your build, and post a link to some photos of the completed platform when you get it done!
Thanks for your reply! I opened your 3D model and tried using SketchUp’s “tape-measure” tool to estimate the Height of your 10″ Zhumell Telescope COG. My estimates of your scope’s COG is:
Height (Y) COG Run (X) COG Hypotenuse COG
model 1: 13.125″ 11.625″ 17.5″
model 2: 13.75″ 12.188″ 18.3125″
From your SketchUp 3D model file can you find out what your COG Height actually was for your 10″ Zhumell Telescope?
Great build. You must at fairly high altitude. At my altitude, 32 degrees with the south pivot design, I am afraid the board is going to become too long. I wonder how to get around that and still keep it simple design like yours. Any suggestions? Thanks.
I believe the latitude where I lived at the time was close to 42 degrees north. Your simplest way to get around the issue could be just to make the entire design bigger to accommodate, maybe?
Reply with image links when you decide and build. Good luck!
Trying to figure the radius of the cone. Is it the height of the pivot on your telescope to the platform.
I am from India , My latitude 20°North . I want to create a platform for my 10″ dobsonian . please help me anyone .
Hi Paul, your platform is really nice. In addition to the many accurate photos of the work done, wouldn’t you also have drawings with the dimensions to be able to replicate the table? Thank you
I am looking for a DIY EQ platform design for so long. Thanks for the photographs, I can understand the design somewhat. I am living in Trichy, India. Will this design work for my place? What are the parameters I gave to change?
My location: Trichy (10.85 N) | Telescope: GSO 8″ Pro Dob | Camera: Nikon D5200
Kindly help me with more specifications about bolts and other necessary accessories for the EQ platform and also for a simple barn door tracker. it would be very helpful.
Thanks for the breakdown of what you did, and your willingness to answer all of the questions! For me the ah-ha moment with this kind of mount was realising that an EQ platform is a cone that contains the telescope, and is rolled along the ground. Imagine that and you can see how it correctly tracks, when the cone axis and the open end of the cone is pointed at the north (or south if you live in the southern hemisphere). The trick is that the cone has been cut down to its most simplified form such that it can just support the telescope, without needing to fully surround it, and is only allowed to roll a few degrees, so the telescope doesn’t fall off. The angle of the axis of the cone (to the ground) is set at your latitude, and this determines most of the measurements needed to build one. I type this in case it helps others understand the fundamental principle of the design.
Correction! Not rolled along the ground – rolled in-place, around the axis!
I am from India , my latitude 20° North . How can I make this type of platform , I am using 10″dobsonian .can you help me .
I also have a 10″ dob and am making a platform for it, but this is a very slow project (i have too.many other commitments and hobbies!). I’m at 32 degrees south. I haven’t yet worked through the details of the design so am not helpful at the moment. I don’t have easy access to tools and a workshop, but do have access to commercial CNC routing at reasonable prices. This means my design will be oriented to easy assembly from commercially made parts, and so at higher cost than Corey’s. I’m using Autodesk Fusion for design. I may also look for ways to substitute more complex motor control for complexity of assembly, because I have knowledge in that area.
Happy to share process at the end, but that may be many months away.
Cory Schmitz, I see you used a clock drive motor on your EQ platform. What size diameter roller did you use that contacts the the angles? Jack
The good thing (and main reason) that I used that particular drive motor was because it was easy to control the speed, which meant I didn’t have to worry too much about the size of the contact roller. I don’t have this platform anymore, but from memory, I would guess that the roller was about 10-15mm in diameter.
Once it was installed, I could easily dial in the correct speed of the drive just by watching for and correcting the RA drift on a bright star far away from the celestial pole.
I hope that all makes sense, and good luck with your project. (…and I wish I still had that telescope and platform, I miss it!)
Hey Cory! Love the design of the stand. Just built my own and it’s working pretty well! However, it’s not keeping the objects perfectly still, even when the motor speed is correctly set and the stand is aligned north. I think I made a mistake in the design.
I have a question related to the angles in your SketchUp designs. In the pic I attached below, should my latitude be the red angle, or the purple angle? I built it with my latitude (~41.5) as the red angle.
I see — your latitude should be the purple angle on your markup, not the red angle. That’s probably part of the issue. However, you should be able to account for that by propping up the back side of the mount a few degrees to make the axis of rotation point at the celestial pole.
I really like your EQ mount, do you have plans with dimensions that you can email me?
Where is the hardware sold?
Cory, what a great post! Got me into building my own platform. I couldn’t figure out your segments so I used the other method found out there. It worked! I think i could do 30seconds subs. Did 15s yesterday without spending too much time aligning the think. My question: What material did you use to transmit rotation (3/8”” OD I presume) to the segment? Is that rubber? Looks thin though. Thanks for your good work.