I finally got around to doing the installation of my belt drive kit and thought it would be good to do a blog post documenting the process. I purchased the kit from Rowan Astronomy who are based in Banbury in the UK for the cost of £89.95. I also bought the optional pinion gear extractor for £9.25. I went for the Rowan kit as it maintains the 9:47 ratio that the Synscan handset needs in order to function correctly. A lot of the other kits I have seen use a 4:1 ratio which means that the mount has to be used with EQMOD in order to work correctly. I currently do not own a Synscan controller but like to leave my options open. The kit itself comes with a set of instructions and this blog is in no way meant to replace them. It is simply me following the instructions to see how well they and the upgrade itself work. I should also add that I have no affiliation to Rowan Astronomy.
Before we start it's worth watching the first part of a "before and after" video that I have made. It can be found here
So lets see what my £99.20 got me
When unpacked it doesnt look like much. You get a set of pulleys and belt for the RA drive and a set for the DEC drive, a set of allen keys, the 8mm spacer, the optional pinion gear extractor and a set of instructions. The supplied instructions are in black and white but you can download and print a colour set from the Rowan Astronomy website here. We do need to take into account that these are precision machined parts and are not mass produced. This is clear in the quality and finish of each item which is very good. Only time will tell if the claimed improvements will weigh out the cost. So what are the claimed improvements? Looking at the Rowan Astronomy website they claim
"The pulley modification reduces the spur gear errors that are typical and
therefore reduces tracking errors. The belts also make slewing much quieter
eliminating the 'grinding' noise that the standard spur gears produce.
The pulley ratio is the same as the factory gears. This means the
Synscan hand controller is unaffected by this upgrade. All Synscan
functions will operate as before."
eliminate backlash, smoother tracking and improved PEC are claims I have seen on the internet on various forums which can fall under "tracking errors" but no direct refference to specific error improvements on the Rowan Astronomy website which is fair enough.
So now its time to start taking the mount apart. I have to admit that I have been a little apprehensive about doing it. Part of me was in the "If its not broke dont try to fix it" camp but the part of me that enjoys tinkering won out in the end and I had to do something about that awful grinding that the motors make when starting and stopping, at 2am in the garden it just seems so loud!!
To start with it is a simple case of removing the gear and DEC shaft covers. 6 screws in one and 5 in the other
This leaves the gears and control board exposed. If you want to do a before and after sound check on the drives now is the time!
Next we need to identify which cable is the RA motor and which is the DEC motor. The instructions have arrows that point to the respective plugs on the board which helps a lot but they are not to hard to trace. The only thing I found was that the cables were all twisted together in a knot to keep them clear of the DEC shaft. Not a big issue but care must be taken to unwind the cables from each other (a bit fiddly) and unplug the DEC motor cable from the board. Its a good idea I think to follow the advice on the instructions and work on one drive at a time
Next stage is to undo the 3 bolts holding the motor and plate in the mount again the bolts are marked on the instructions but it is fairly obvious. Carefully remove the motor keeping an eye on the wires and threading them through the housing
The larger gear and pinion slides out easily once the 2 grub screws are undone. This is no longer needed so can be disposed of if you wish or keep it as I dont see any reason why this mod can not be reveresed.
Once the larger gear and pinion is out the plate that sits on the motor needs to come off. This incolves removing the last 3 bolts. Be sure to keep these seperate from the first 3 as they are different lengths. It also mentions in the instructions that, to save time when re-building you need to note where the wires come out of the motor in relation to the orientation of the plate. When you get to this stage it becomes apparent that this is a good idea! I marked the plate and motor in one corner as seen in the picture.
With the plate removed the smaller gear can now be accesed using the optional pinion gear extractor. For the sake of £9.25 I would strongly reccomend this unless you already have something that will do a similar job. Just trying to pull the gear off the shaft with pliers would be difficult and may bend the shaft which obviously would be disasterous. You will need to employ a pair of pipe grips or something to hold the extractor while you turn the allen key.
Just to add a note to the above. The screw in the gear extractor wasnt actually long enough to pull the gear fully off of the shaft. With the screw wound fully in the shaft was still around 2mm inside the gear. This meant that I had to very gently lever the gear off using pipe grips under the gear pulling upwards which was a shame (and goes against what I said above). I dont think this is a fault with the extractor itself as it worked perfectly on the RA motor. Possibly a slight difference in gears, who knows?
With the gear removed the new 9 tooth pulley can be slid onto the shaft. The instuctions mention leaving a 5mm gap between the motor and pulley but to be honest I found that the pulley slid down as far is it could go and this naturally left the correct spacing.
The shaft that will hold the idler wheel is place into the motor plate and should finish flush with the top of the pulley as in the picture. I found the shaft to be a tight fit and it needed a little tapping from a rubber mallet to get it down. Once in place the 2 grub screws are re-tightened.
The motor plate is then fixed back to the motor
Now we need to turn our attention back to the mount. The large cog that is attached to the worm gear needs to come out. Make sure you undo both grub screws. I didnt read the instructions properly and was trying to prise it off with a screw still tightend. The instructions mention that it may need a little levering to get it off but once both grub screws were undone it slid off easily.
Once off you can then fit the new pulley in its place. I tried to line up one of the grub screws with the flat spot on the shaft but I think the screws are too low down to catch it. I dont think this will be an issue as 2 screws should hold it nicley.
At this stage you could turn the pulley by hand to make sure it is rotating the worm gear. Once satisfied the motor can be reintroduced into the mount housing leaving the fixing screws a little loose and feed the wiring carefully back up to the control board and plug it back in making sure the wires are clear of the DEC shaft
then slide the idler over the pin which is not fixed and is allowed to move freely and feed the belt over the pulleys and idler as shown
The motor can then be slid back away from the worm gear pulley to tension the belt as described in the instructions and the 3 screws tightened to hold it in place.
Now is a good time to test the DEC drive to see how it performs. When if fired up the mount every thing was running very smoothly with no slipping. I should add that this was done with no load on the mount that will be tested at a later date. The only slight issue I noticed was that the belt moved up and down on the pullyes a little depending on which way you ran the mount.
This first picture shows the belts position aftering running the mount in one direction. The belt showed no signs of moving any further than this.
This second picture shows the belt position after running the drive in the opposite direction for a while. As you can see it has moved up the pulley a fraction. Again it got to this position and stopped so I dont think there is any risk of it coming off. This must be something to do with the alignment of the 2 pulleys but to be honest I cant see that it will be a big issue but we shall see when it comes to testing the mount properly
The install process is the same for the RA axis so just go back over the instructions. You will probably find now that you have done one drive that the RA conversion will take you less time to complete. When finished it should look like this
Now head back to the Youtube video to watch the "after" part to see what they sound like
Then it is simply a case of fitting the covers back on including the new 8mm spacer and checking everything works.
Straight away when I got to this stage I could here something rubbing on cover when turning either axis. It is difficult to tell exactly what it was but having taken the cover back off I could see that one of the small pulleys had left a grease mark on the cover which was a big clue. I contacted Rowan Astronomy and asked for advice from the online community and found out that this is not an isolated problem. It is due to a 1 or 2mm difference in the casting of the mount housing which raises the whole motor assembly up just a fraction. Rowan Astronomy were exellent in their response and sent out some small 2mm spacers that will sit between the motor and the motor plate to sink the pulley in just a small amount (2mm). I have not fitted them yet but just to give you an idea I have illustrated the picture below
I am very happy with the install part of this upgrade. So far, so good the noise that the system used to make when starting and stopping has gone. The service from Rowan Astronomy has been excellent and its safe to say the supplied instructions make this a fairly easy mod providing you have a little DIY skill. I think the only real issue is the very slight differences in the mount housing dimensions but its impossible to cover all posibilities out of the box.
I would like to go right ahead and reccomend this to anyone who is thinking of doing a belt upgrade to their HEQ5 but ill will hold fire until I have tried the mounts tracking and guiding and checked im happy with what im getting Im looking forward to testing the mount to see how it performs. I shall report back my results!
A small contingent from the Worthing Astronomers, me included headed down to the Somerset coast for the St Audries Bay star party on the weekend of April 4th. This new addition to the star party calendar is on a camp site located just to the east of Minehead in West Quantoxhead and promised some very dark skies for observing and imaging under. Rob Aro and I arrived at around 3PM on the Friday afternoon to a patchy sky but the forecast for the evening did carry some hope.
We were immediately struck by how beautiful the coast line was with views across to Minehead in the West and out across the Bristol Channel to Wales in the North and there wasn’t a street light to be seen!!
As more and more people started to arrive there was a great atmosphere building and it was really nice to put faces to names that we had conversed with in the past on the Facebook groups but never actually met.
For a new event it boasted a great line up of speakers
John Slinn, founder of Disciples of the Dark Arts, Nigel Bradbury, commentator on the Aurora flights, Nick Howes, professional astronomer at Kielder Observatory and Damien Peach, world renowned planetary imager.
Image: Andy Lee
As well as trade stands from Io Astronomy http://www.hampshireastronomy.co.uk/ and SCS Astro http://www.scsastro.co.uk/
Image: Andy Lee
Sadly on both evenings the weather never really cleared. We did get a very brief clear patch on Friday afternoon/evening which gave us a chance to do some solar observing through John Slinn’s solar scopes and we had a few small patches later in the evening which gave us glimpses of Jupiter and the Moon. but nowhere near enough to any imaging done. We spent our time tinkering with set ups and exchanging tips and ideas. It was great to be in a place where everyone shared a common interest. Looking forward to next year!!
This shot of a Sundog was the only astro related shot I took all weekend
Huge thanks to the Staff at St Audries Bay Holiday club and also to Andy Lee for putting in the hours helping to arrange the event!!
To keep up to date with St Audries bay visit there website here
Important. Never view the Sun without a suitable Solar Filter! Solar observing can be dangerous and can be hazardous to eyesight.
I purchased a sheet of Baader astro solar film to try my hand at some white light solar observing and imaging and along with a friend have been playing around with different ways to mount it to my scope safely and effectively.
Please keep in mind there are 2 different filter densities available ND3.8 PhotoFilm and ND5.0 Safety Film. The ND3.8 PhotoFilm is not intended for visual observation. It is only for use with telescopes for high magnification photographic work. The ND5.0 Safety Film is of a higher density and is suitable for observational work and photographic use, it is also a lot cheaper than the ND3.8 so please make sure you purchase the correct film. As I wanted to do both visual and imaging I opted for the ND5.0. I decided to make this "how to" to show you, the reader how we went about making a simple filter attachment for the small 40mm aperture hole on the front of my 150P using some ply wood, glue and a few screws.
To start I cut 3 75mm circles out of some 6mm ply wood
As an alternative you could use thicker ply wood but this is all I had in the store.
I then cut 46mm holes through the 3 75mm circles.
I then glued 2 of the doughnut's together using contact adhesive to give me the required depth (here you could use thicker ply if available negating the need for glue) and drilled 3 pilot holes in the 3rd doughnut.
This left me with 2 doughnuts. 1 at 6mm depth with the pilot holes and the other 12mm deep.
Using the doughnuts as a template I cut a square of solar film large enough to cover the full 75mm diameter
Sandwiching the solar film between the 2 doughnuts I screwed the top piece right through the film and into the wood behind and trimmed of the excess solar film
I had to cut a notch out of the filter to allow for the raised lip around my scope end cover. This allowed the filter to sit over the 40mm hole flat
And here is the finished article. The 46mm internal diameter ensures a nice snug and tight fit over the hole. I will have to keep an eye on the fit as it may become loose over time through use and I’m looking at perhaps making a MkII out of nylon. Another safety feature I’m also considering is a bolt that runs right through the filter and end cover so the whole lot is bolted together.
If you decide to have a go at making one yourself you do so at your own risk. You need to ensure the filter is checked for pin holes or any damage before every use. I do this by shining a bright torch through the filter first and if that’s ok ill hold it up to the sun and check the whole surface of the filter
Here are a couple of images I have taken to date using this filter. The first showing some sunspot groups and the other shows the transit of Venus
Sunday March 16th saw the shadows of Io and Ganymede on the disc of Jupiter at the same time. A few of the Worthing Astronomers and I headed down to Worthing seafront and set up on the promenade to capture this event
The evening started really well with lots of frames being captured in the build up to the double transit which started at 22:22. Almost unbelievably at 22:10 my Battery started to die (My 17Ah battery is no longer adequate). Fortunately I was lent a power supply just in time to capture some frames that I stacked into a half decent image. I have achieved better with the little SPC900 before but I think the power failure and the rush to maintain my tracking didn't help
This is 1600 frames taken using my 150P and the Phillips SPC900 aligned and stacked in Registax 6
On the 28th of November the long awaited comet ISON (C/2012 S1) will reach perihelion (closest approach to the Sun). And we shall finally know if it is going to survive intact and give us a show to remember
The comet was first discovered by Vitali Nevski and Artyom Novichonok, 2 Russian astronomers working with the International Scientific Optical Network (ISON) which is where the Comet takes its common name. At the time that it was discovered the comet was 6.29 AU from the Sun (1 AU = the average distance between the Earth and the sun which is around 150,000,000km or 93.2 million miles).
The comet is on what’s known as a hyperbolic trajectory meaning it is in a tight elliptical shape around our Sun. This suggests that it is a fresh comet from the Oort cloud, a hypothesized spherical cloud of icy debris left over from the formation of the solar system and lies around 1 light year from the Sun. Nearly quarter of the distance to the next nearest star. If the comet does survive its spin around the Sun it will be travelling fast enough to escape our Solar system never to return.
The Comet was initially dubbed as the comet of the century as it was predicted at first to become very bright perhaps even bright enough to be seen during the day but as the comet has been getting closer and its brightness monitored it now looks as though it is going to fall below its initial predictions. This graph compiled by Seiichi Yoshida from Japan shows the comets initial brightness prediction as a blue line, the black dots show the measured brightness at different intervals and the red line is the current prediction which still is pretty good. Seiichi’s website has more information here and is well worth a browse!
On October 1st comet ISON passed close to Mars at a speed of around 35 Km/s (80,000mph) and a distance of 10.5 million Km which is closer than it will get to Earth. The Mars Reconnaissance Orbiter took these images as it flew past.
We have to keep in mind that both the orbiter and the camera were not designed to do this kind of work so it took a fair amount of effort to get these.
Ernesto Guido, Nick Howes, and Martino Nicolini captured this image of the comet as it was passing Mars using the 2 meter Liverpool telescope. It shows an already impressive tail and coma. Which the team state, was at 3 arc minutes in length.
The comet is currently visible in small telescopes but you will need to be up early and have a good clear Eastern horizon to see it just before sunrise. This image shows the rough location on Nov 3rd at 3am UT by this time it will be just about inside the orbit of Earth continuing to accelerate towards the sun. At this point it is estimated to be around magnitude 7 but its by no means a certainty.
As we head on through November the comet will be getting closer and closer to the sun becoming a daytime object and unobservable and then, on the 28th of November at 18:32:38UT (JPL prediction at time of writing) it will come within 1.2 million miles of the sun’s surface. If it survives this very close encounter it will be flung around travelling at a staggering 845,000mph back out of the solar system and then hopefully the comet will become considerably brighter possibly visible with the naked eye and by mid to late December we will start seeing it at a more sociable evening time. The comet (if it survives) will make its closest approach to Earth on December 26th at a distance of 40 million miles. Let’s all hope that it does make it around the sun and give us something beautiful to observe and image but as for it being the comet of century? I guess we’ll have to wait and see. For more info about comet ISON visit www.cometison2013.co.uk Below I have added finder charts for early November. The comet will get lower each day.
I decided about a year ago that I wanted to try and improve my astro imaging so as well as an upgrade to an HEQ5 pro I also wanted to try my hand at building and installing my own pier in the garden. I started by doing my homework, numerous hours trawling the net for ideas, methods, do’s and don’ts. The pier had to be aesthetically pleasing as well as solid and functional. After I had an idea of what I’d like to end up with the next task was location.
So here is my garden. It’s small and doesn’t have a great deal of space to play with. I needed to place the pier in a position that would give the best possible views whilst also not impeding on the garden too much. I decided to go for an area roughly in the same place as the red ball (yes I did put it there for the purpose of the picture).
The garden provides views North, South and West (East being blocked by the house) down to around 20/30 degrees above the horizon.
It is important to ensure you know the direction of true North. The more accurately you set your pier to this the easier your polar alignment will be. This Website is very good for determining true North. You simply find the location of where your pier is going to be sited and put down the marker. This gives you the longitude and latitude co-ordinates. You then add another marker keeping the same longitude but increasing the latitude a little towards the North. This gives a 2nd point that is exactly (true) North of you pier location.
Unfortunately when the picture was taken we had a gazebo in the garden so I had to estimate the rough location indicated by the red marker. The blue marker is true north which puts it roughly between the 2 vent stacks on the roof circled in yellow.
2. The Pier
Now the location and a rough direction were set it was time to look at the pier itself. I wanted to have around 900mm to 1 meter above ground and decided on around 500mm to 600mm below ground with a square plate on the bottom encased in concrete. A quick design in MS paint and I ended up with this.
I was lucky enough to acquire some left over pipe and some 13mm plating from work which along with these drawings were given to the fabricator to be cut and welded for which they charged me £30.
I needed now to come up with a way of attaching the mount to the pier and found a few examples on the web that were using car brake discs. One of the sites listed the disc I would need to take my HEQ5 perfectly. I found it on eBay for £10, turns out it was for a Skoda Favorit
The dimensions are
Overall diameter = 236mm (this governed the diameter of the top plate I had welded to the top of the post)
Overall height = 46mm
Centre hole diameter = 62mm
Disc thickness = 12mm
A commonly seen method for attaching disc to the top plate of the pier is to raise the disc a few inches above the top plate using threaded rod. This then allows you to access the underside to tighten and undo the hold down bolt of your mount and also allow levelling adjustments as shown in the image below
Purely from an aesthetical point of view I wanted to try and avoid this although I don’t think it makes any difference in stability. To achieve it I had to overcome 2 main issues. Firstly how was I going to gain access to the hold down bolt if it was down inside the pipe? And secondly without the threaded rod how was I going to level the top plate?
To access the hold down bolt I insured I had a 100mm hole in the top plate and I simply cut a 70mm hole in the side of the pipe. This allows just enough room to get a hand onto the hold down bolt to tighten and undo.
I had a large stainless steel “washer” made up that fitted nicely inside the boss of the brake disc with an M10 threaded hole in the centre. The recess in the washer was cut deep enough to allow the mount to sit flush with the top of the disc and allow for the thread of the hold down bolt to protrude through without touching the bottom of the mount. It was important to ensure that the
washer was larger than the 100mm hole in the top plate to stop it dropping to the bottom of the pipe when the mount was not attached.
The hold down bolt is then screwed through the threaded hole in the washer and the whole assembly inserted into the disc. The mount is then added to the top of the disc and the hold down bolt is wound into the mount thread until tight. This holds the whole thing together nicely.
I then bolted the whole thing to the top plate to test it and was very happy with the results. I was satisfied that it was time to put it in ground!!
3. Time to dig a hole!
It was a few weeks after my first initial tests that I got a chance to start work on the hole. In that time I also had the pier and disc powder coated in gloss black, I knew where the hole was going (see first picture) and I knew that I was aiming for around a 500x500x600 deep hole. This would be the first time id had a go at something on this scale but I had an assortment of tools to assist
including a 100mm manual post auger, a pick axe, a pair of scissor shovels and the customary garden spade and fork. I know very little about ground work but I do know one thing…….flint is hard!! And when you are digging a hole in ground that seems to be more flint than earth it is pretty hard going! As it turns out the combination of pick axe and garden spade seemed to work best until I got down deep and had to use a trowel to excavate what the pick axe had loosened. It took the best part of day to dig the hole but was kind of satisfying (not to mention a relief) to see it finished
The second issue about levelling now needed to be addressed however, having a perfectly level pier is not essential and polar alignment can still be achieved so I was going to be happy as long as I could get close to level. I added some reinforcing bar to the bottom of the hole and levelled them as best as I could. Nothing technical just a hammer and a spirit level checking in all directions.
Once I had them somewhere close I mixed up a small bag of post-Crete and poured this into the bottom making sure it covered the bottom and buried the re-bar. I allowed this to harden a little before trowelling it over again getting it as close to level as possible I also added some polythene sheeting which I hoped would help with moisture. It was now time to carefully lower the
pier in and allow it to sit on the re-bar. This forced the still workable post-Crete around the side of the bottom plate and formed a nice barrier (as far as I could tell) between the ground and the plate. Possibly all a bit OTT but I thought better that way as it was a simple thing to do
I put a small circular spirit level on top of the pier and manipulated the whole thing until I was happy it was level and managed to get it very close.
Over time I expect the pier will go out of level as the ground moves but I’ll keep an eye on it worse case is that I’ll have to raise the disc up using threaded rod or perhaps add some shims but only time will tell. I then had to mix and add the concrete. In the end I used 16 bags of B&Q’s ready mix concrete which was more than I had imagined needing and was very grateful for the loan of cement mixer. We were fortunate enough to get some prolonged good weather so I picked a day and went for it with assistance from my wife. You may also notice that the tree at the back of the garden has gone!!
It was simply a case of pouring the concrete into the hole whilst all the time checking the spirit level on top to make sure there was no movement. I finished the concrete around 100mm from the top of the hole to allow me to add top soil and grass seed when the concrete had cured and left it for around 1 week to harden checking the level every now and then to see if it had moved.
The next task was to add a small spigot to the top of the disc for the azimuth adjustment screws of the mount to work against. Although I had made my map showing me where true north was I decided it was far easier to attach the mount and perform a polar alignment of it to give me my true north position. I cantered Polaris in the polar scope using the altitude bolts but manually
twisting the mount in azimuth. My thinking was that if Polaris was centred in the scope cross hairs and I took that as my true north direction I would have enough azimuth adjustment in both directions to properly polar align. Once centred, I marked the mount outline with electrical tape.
This left me with an idea of where to drill the hole when the mount was removed. I measured the thickness of the metal and added another strip of tape. The pencil mark shows where I needed to drill
I drilled an 8mm hole through the disc and attached an M8 threaded rod connector which is just high enough for the azimuth bolts to hit.
Tests using the azimuth screws showed that it works perfectly and here is the finished pier with mount and scope attached.
Going forward I plan to add something to the top when the mount is not attached possibly a sun dial or a bird table just to give the post another use. I may also fill the post with cement or maybe just sand as it is possible to drop things down inside the post and it may also fill with water.
I have also added my first image taken using this pier. For the first time I took 180sec exposures which is pretty good for an unguided set up but I plan on trying 240sec next time.
In conclusion I really enjoyed doing this project and if anyone is considering having a go I would say go for it. The stability that I get now for both observing and imaging has improved considerably my only wish is that I could take it out into the field with me and use it under truly dark skies. I
hope this write up has provided some inspiration and ideas to help get you started.
If anyone has questions or would like advice I can be contacted via email at email@example.com
Since starting in this hobby several months ago one of the things that have become evident to me is just how expensive it can be. Almost from the outset I started to want to photograph the things I was seeing to be able to share them with friends and family but the cost of the equipment put this beyond my reach, or so I thought.
Whilst looking into the basic techniques involved with astrophotography I stumbled across a well developed way of using everyday computer webcams to capture some pretty impressive images of the objects within our solar system and with modification can also be used to image objects much further away. Although there are lots of webcams on the market that can be used one standout model is the Philips SPC880NC which has had its software changed (flashed) to be the same as the older discontinued SPC900NC.
I purchased one of these cameras complete as a Kit which came pre-flashed with a 1.25” nose piece and an infra-red filter which is easily attached and there are numerous “how too” guides on the net to help. The camera is inserted directly into the telescopes focuser with no need for an eyepiece (prime focus photography). I use 2 pieces of free software to capture and process images although there are lots of different ones out there it’s a case of finding what you’re comfortable with.
Firstly SharpCap which I use to capture video footage from the webcam which is saved as an AVI file. The software has features that allow me to adjust the webcams setting in real time so the effects can be seen in the preview screen. There are also tools to help with focusing and the ability to convert the screen to night mode.
Once I have my recorded AVI footage I load it into RegiStax which again is free to download and is used to stack the video footage and process the final image. The software will firstly look at the quality and alignment of the individual frames from the video and remove any that don’t meet your pre-set benchmark. It will then take your remaining frames and stack them on top of one another to create a single image. Once the image stacking is finished you can then adjust the brightness, contrast and sharpness to further bring out detail.
I do then tend to use either paintshop or GIMP to further enhance or touch up the image.
There is a surprising amount of free to download software available on the internet to give anyone an introduction into astrophotography without having to spend hundreds of pounds.
Primers and tutorials are also easily found on the net for all of the processes I have mentioned. I think so far not including the telescope my entry into this side of the hobby has cost around £40.