Saturday, December 31, 2011

Integration hardware

Now, I've two worm driven slow motion controls as detached from a new Porta-like mount, and I also have a ball head, but I will need some ways to put it on the Mark-X.

In order to do that, I've ordered two 6061 aluminium bar of 2cm * 2cm, with that kind of thickness, it should be able to provide shake free attachment.  These solid bars were not cheap at all, but then it's still only 30-40% of the price quoted by a local machinist.

All I will need to do is to drill two holes to mount them to the Mark-X, and drill two more holes to put on the slow motion controls, and maybe one more hole to put on the ball head.

Actually, I've an 9mm thick solid alumnium bar at home which could be used.  But after drilling the holes, its wall thickness near the hole became less than 1mm (with a 1/4" hole) which is just too dangerous and will break suddenly without any warning.  So a 20mm thick bar should leave some more safety margin.

Updated on 2012-1-3:-

Due to the new year holidays, the package arrived today finally.

On fixing to the Mark-X, my existing M5 screws should be long enough since the existing mounting hardware is exactly 2cm thick.

On fixing to the slow motion controls, I will need four M6 screws which is slightly longer than 2cm, and 2.5cm should be about right. 

Updated on 2012-1-7:-

6061 2cm by 2cm aluminium block is harder to drill than I imagine.... anyway, persistence is king.

For the first block, I didn't lock the metal block firm enough and it was released suddenly and it hurts my hand lightly.

So for the second block, I used a clamp to fix it in place, and in order to attract all those metal debris in place, I have placed the metal block in a cup of water before drilling, and keep adding droplets of water to reduce the temperature increase during the drilling process:

Drilling holes through thick metal block using a hand drill is difficult and it's hard to be very accurate.

The attachment was firm and secure, but the metal block was a little bit too thick such that the polar scope cover could be fully screwed into place afterward.

Later I found that I just don't need the dovetail saddle, and all I will need to do is to mount my Ranger directly to the M8 mounting holes on the slow motion control.  I've drilled a hole on my Ranger mounting ring in order to do that. 

On the other side of the Mark-X, I left opportunity to mount a camera ball head or another slow motion control.

Thursday, December 29, 2011

Altazimuth mount arrived

It arrives in great condition.  It works quite good and it's built quality is pretty good as well.

The worm shaft was 6mm and I've some brass gears and metal shaft couplers on hand, motorizing it should be rather easy by mounting my existing DC geared motor to it.

Removing those slow motion controls were easy as well, you can always assemble it together again if you want.  It could be attached to the Mark-X rather easily by using a simple L-shape plate.

A fully operable dual-axis EQ mount should be ready very soon!

The bottom half of the mount could be used very easily as a portable EQ mount!

I've further removed that 3/8" adapter on the bottom half and so I got two identical worm driven slow motion control as shown below:

On the bottom side, there are three mounting screws but there are six threaded hole for mounting in total.  On the top side we had 8 M8 threads holes, these holes come in four opposite pairs separated by 35mm which is Takahashi compatible.

On the upper unit, a Vixen compatible dovetail was included and fixed by four M8 screws.  The lower unit was fixed to the mounting arm with two M8 screws.  There units were filled with typical Chinese glue like grease but they worked quite well actually.

Monday, December 26, 2011

Portable EQ tracking mount idea

There are several portable EQ tracking platforms available from the market, like TP-1 from a local dealer, a CD-1 from somewhere else.  Now, I'm wondering if it could be made rather easily with off-the-shelf components.

First of all, the mechanical part could be acquired by disassembling those Vixen Porta-like mount (120 tooth), by doing that, you can effectively make two such EQ tracking mounts.

Secondly, the motor could be hacked by other existing RA tracking motors.  For example, the Carton CXD-1 controller which I bought.  One can always change the crystal to adapt to the different teeth numbers.

With that in mind, you will be able to have two such mounts by disassembling two Porta-like mount !  Even if we factor in the cost for those Aluminium plates and screws, we can easily keep the cost rather low.

I shall explore such opportunity once the Vixen Porta-like mount arrived.  I've at least one of the two axes as spare part.  I guess I can keep this kit at around $1000 HKD.

Saturday, December 24, 2011

2011-12-24 Jupiter

Home alone in the Christmas Eve, I pulled out my Canon 100-400mm f5.6L for some fun.  Mounting it on my Mark-X, it's an easy loading indeed.

I'm trying to use my Canon 450D for planet imaging with EOS Camera Movie Record by using its LiveView mode.  I'm using the latest version which supports 5x as ROI so that you can move around the chip!  That's really great for centering the planet since we have a really huge APS-C chip especially when compared to a 1/4" ToUCam Pro CCD or a 1/3" Lumenera LU070M CCD!

The "motorized focuser" of the Canon 100-400mm is a joy to use, you can even remote control it via USB with software.  It's just silent and accurate with the USM, a fantastic experience.

I've tried to use it at 400mm f/5.6 but it's too short for fun, so I jumped up with a Kenko 2x and thus it becomes 800mm f/11.

With the extremely poor seeing tonight, the two major cloud belts were well resolved.  So there's a good potential actually.  I'm using ISO 400 at f/11, 1/60s.  Notice that a regular telescope can do f/25 easily and thus, I believe I will need another 2x to fully unleash its power.

Ordered an altazimuth mount!

Why I am doing this?

First of all, by selling my TG-SP II, I got back some cash together with this Mark-X, but even if I inject 1/3 of the original cost of my TG-SP II, I would be able to get back a fully operable mount, so it's a real bargain, indeed.

I've a plan to remove the slow motion control of this altazimuth mount and re-fit it to the Mark-X as the DEC axis.  This will facilitate high power imaging.  In addition to that, from what I've seen, this part should be motorized rather easily, so I will have a dual axis mount for higher power imaging.

For the other axis, maybe it could be used to aid polar alignment?  I don't know...

That's the first time I bought stuff from, see how it works out.  The pricing is definitely attractive.

Friday, December 23, 2011

2011-12-23 Jupiter

Temperature keeps dropping along in this windy night.  Seeing like 0.5/10, too bad that I don't want to rate it.  Jupiter appears as a featureless disc except during some very brief moments with that two major cloud belts.  You can't even know you're in proper focus.

Armed with my motorized Mark-X, tracking is a joy even with rough polar alignment.  This motor delivers a lot of torque even I've nothing on the other side for balance, it tracks very well!  Here's a shot with the existing mounting adapter which is heavier than the mount body!

So you see the scope was actually quite far away from the RA axis, so the torque could be huge even with a small scope, but the motor works very well.

Due to the poor seeing, I just did an over-exposure to bring out the Jovian satellites at prime focus (i.e. 480mm):-

With this initial success, I pushed the power to 960mm and then capture thousands of frames with my LU070M, and after stacking, the cloud belts were clear and good:-

Knowing the poor seeing, I pumped with the image scale with 2400mm but then nothing could be seen as expected, I just want to try out the tracking. I've to adjust the DEC axis manually in order to re-center my target after several minutes of tracking, but this is a result of poor polar alignment rather than the tracking motor. It seems like if I want to do high power imaging, I would need a motorized DEC as well... it should cost me something like another $600 HKD, got to think about that. But I won't do it at this moment.

I'm getting some fun out of my good old setup.  The adventure with the Mark-X brings a lot of joy without any high cost.  It's why amatuer astronomy was so much fun.

2011-12-23 Sun

Closed window shot, tripod was not used, just the Ranger leaning on a metal block, and a simple ballhead, I even had to fix the setup in place and asked Alby (my elder 9 years old daughter) to click the record button for me.

The darkest patch on the lower left is AR1384.

It seems like the local friend-like dealer does not have density 3.8 Baader filter, so I will need to search for it on the internet.  On the other hand, I've another idea to built the mounting adapter of my Mark-X, it might carry four instruments at once but it's not the main point, the whole idea is to make it more stable but the capacity to carry more instruments is just a side effect.

Monday, December 19, 2011

2011-12-19 Sun

It's time to test my Mark-X after the integration with the Carton CXD-1 motor (Tele Vue System Mount OEM).

I'd say it works perfectly, I've zero complain.  Despite my existing mounting plate does not allow balancing, the motor proved to deliver enough torque to turn the mount very nicely in both directions, and even at FAST mode, it works great without any major backlash.

First one is taken with my DIY blue filter with reducer lens, so I can take the solar disc in a single shot:-

Second one is taken with a 2x barlows plus a green filter, close up of AR1381 and AR1382:-

Only the original Ranger focuser was used, the mount is a bit shaky during focusing so the focus is not very accurate.


I left the motor running for several hours after taking these images, and it tracks nicely. 

Longing to test it under the star, maybe I shall try it out tonight from inside home if possible.

GOTO Mark-X: Improved motor mounting

The initial mounting method has been quite ugly and ad hoc, so I took the plunge to go back to my original design. That is, to drill a hole on the original motor cover in order to fit a long bolt to connect to the mounting hole of the Mark-X. The drilling hole couldn't be too accurate since I don't have the proper tools and skills. Therefore, I started off with a very narrow drill bit so that I could refine the position after the initial drilling. After the initial drilling, I found that I am pretty on-spot and it should be accurate enough after fitting it to the mount. A good sign, but a drill bit was killed during the process which was expected. That I changed for a thicker drill bit to do the final drilling. It turns out to be accurate enough especially I was using a flexible shaft coupler which allows a little bit more tolerance. This is the final product:

Pretty elegant, right? In order to fix the motor in the field, all I will need is a small hex key to engage the shaft coupler and then I will need to fix a small nut at the other end.

Actually, the bolt head was a little bit too thick to hide completely inside the motor cover, but then it's just a little bit over.  You can see from the photograph below that the motor cover was not completely hide below the black compartment, but it's fine enough.

So far it's one of my best DIY projects.  I'll do a beta testing soon by using the sun as my target.

Next Step: A Better Mounting Plate
  1. Lighter in weight
  2. Allow balancing
  3. Cheap and simple 

Update 2011-12-19:

I've inserted a nylon locknut on the other side of the mounting hole on the Mark-X, it further fixed the motor in place.

For the mounting plate, I tend to keep it simple and stupid in order to keep the cost low.  Currently, I'm thinking that I might give up the facility for balancing by sliding since it is much simpler to make, and it's far more compact for transportation.

In order to alleviate the problem, I will keep the mounting plate very short so that the torque due to imbalance would be reduced.  Secondly, I can always hang the battery pack or attach something else on the lighter side to enhance the overall balance.

I've some ideas in my mind by using short angle aluminium plate and I've some scratch materials at home so that I could do some testings without cost.  The only problem is whether the vibration damping would be good enough or not, and also the varying degree of flexure during tracking.

I believe this idea would work, the problem is the choice on material.

I guess thicker angle aluminium plate would work, the problem is where to buy them.  If that was not strong enough, I think thicker aluminium bar will do the job, the problem again is sourcing.

Saturday, December 17, 2011

GOTO Mark-X Alpha Testing

I have been longing for this. With the shaft couplers and the screws on hand, I proceeded to do the integration this morning. First of all, I found that stainless steel plate which I've bought yesterday was too strong, the electric drill was not doing well on making holes on it, or even just to enlarge the holes. I guess it could with some more persistence but it might kill several drill bits before it could be done.

I have used a very soft aluminium plate which I already had to do the job, and it worked out fine.  In short, here's a short video to show it at work!

Originally, I have mounted the motor on one side but then I found that the 410 head would block its way and thus, I have to move it to the other side of the mount.

Fully assembled and ready for testing.  So, I have attached the heavy DIY mounting plate of the original owner to it, mount my Ranger on one side and the do some ugly solar imaging.

It's really nice to have a motor, you can use it to fine tune the position of the target and you can have the target stay in place without moving the setup a bit.  Vibration of this stepper motor is minimal.  Since I was only testing the motor, I didn't even open the window to shoot the sun, so the image was ugly but then it serves the purpose of testing the motor.  I don't even bother to process it carefully.

So far so good!

Here is a list of pending tasks:

  1. To find a good and quick way to remove and re-attach the motor in the field.  I expect my mounting screw and plates will break very soon if I kept them in place during transportation.
  2. Fine tune the trimming capacitor with good polar alignment.
  3. Further improve the mounting
  4. Make a better mounting plate, the existing one was too heavy and it lacks the ability to allow proper balance.
  5. Anything else?

Wednesday, December 14, 2011

The Crystal Arrived - the quest for Mark-X motor

The stamp reveals that it comes from Thailand, it's well packed and in great shape.

With some careful observations, I've cut off the old crystal which is longer and bigger in size.  I've carefully bended the legs of the new crystal and try to fix it in place with a tape.  Then I proceed to solder it in place.  It's not an easy job since the legs were in a rather crowded place.  I tried to melt a tiny ball of solder and then dip the whole ball into the joints.

After the soldering work, I switched on the power to check the time required for a complete rotation, it should be longer than 8 minutes (180 teeth with the original crystal) and it's hopefully 11 minutes and  25.7 seconds (126 teeth with the new crystal), but I know the speed will be slightly different since the crystal is not really 3.68MHz but 3.6864MHz.

With my best effort timing, the time required for a full rotation is now 11:10s.

After adjusting the trimming capacitor for two clockwise turns, the time for a full rotation is then 11:22s.

And the third adjustment yields 11:26s... and I won't adjust it further, since my timing method should not be accurate enough to be meaningful.

Still need to wait for the shaft coupler, and then I shall attached this motor to the mount for a real test under the stars!


Original crystal carefully removed:-

New crystal placed in location:-

Ugly soldering job done:-

Updated 2011-12-16 (afternoon):-

The source of this motor is pretty good, the seller said he has more than 50 pcs in stock.  Thus, I won't bother to buy backup at the time being.

When I go out to work this afternoon, I found that shaft coupler was already in my mailbox, it's very nicely machined with light weight but thick aluminium.

On the way to office, I have bought several M6 screws, nuts, and a small stainless steel mounting plate.  And I guess I shall be able to fix them together.  Hopefully I won't need to drill any holes except to enlarge a few holes by tapping.

 Updated 2011-12-16 (night):-
The shaft coupler gives a perfect fit.

The M6 screw for the mounting hole on the Mark-X fits very well, too.

The M6 screw for the motor fits excellent as well.

But that small mounting plate needs bigger hole to accommodate the M6 screws but then it's harder than I imagined, so I will need to enlarge the holes tomorrow with a drill. Can't do it tonight since I've no drill on hand.

Monday, December 12, 2011

Another Mark-X mounting plate

Sliding mounting is not strong enough and it is actually not really needed, for balancing, all we need is a single sliding mounting slot.

The L part is for mounting a rotatable quick release plate for my Ranger.  It should be made as close as the polar axis so that it could be balanced easily.

Cabinet clearing sales update

Package deal: $999 HKD takes them all! 

Or name your price, reasonable offer will be entertained, just don't want to waste all these stuff.

Astrotech 1.25" dielectric diagonal in great condition, flawless mirror and with the original box, ask for $350 HKD (SOLD).

Shoestring FCUSB, virtually new never used in the field, ask for $500 HKD. Control and power your JMI focuser via your USB port.  Ask for $500 HKD.

Sealed Lead Action battery, reliable power solution in the field. Comes with a Panasonic 12V 7.5Ah SLA battery, a charger which will take 12V or 6V SLA, and also a generic notebook transformer which offers 15-24V by using the 12V SLA.  Ask for $100 HKD for all three!

Next is a 70mm doublet (f=500mm) mounted and with 77mm thread, suitable for macro imaging which brings the closest focusing distance down to less than 500mm. Ask for $200 HKD.

Celestron Nexstar mount parts, the gears were still available at $100 HKD as shown below, the bigger one was about 6" in diameter and the smaller one was 5".

JMI 2" -> 1.25" compression ring adapter, $100 HKD:-

DIY 43mm male thread afocal imaging adapter, $20 HKD (SOLD):-

Never used JJC EC-2 Eyepiece Extender for Canon EOS DSLR, $30 HKD:-

Another custom machined 2" to 1.25" adapter, it's pretty heavy and could be good for balancing light weight 1.25" eyepiece and heavier 2" eyepiece. With two locking screws for added security.  Ask for $50 HKD.

Originally for my Gitzo G1415 when I lost one of the spikes on the legs, so I still have two remain. I've sold my G1415 and now they're sitting idle... very hard to find in Hong Kong and even the distributor refused to order them for me. Ask for $200 HKD.

A small 7-14x monocular, good quality for this size, ask for $50 HKD.

GOTO Mark-X mounting plate with counter weight, ask for $200.  The gray mounting plate was sold and is not included.

Brass counter weight, 3kg with 20mm bore, ask for $100 (SOLD).

20111212 Sun

Yes, I'm going solar imaging again with my pinholes filter.  I do it because I would like to try out my latest configuration of my Mark-X.  A simple rotatable quick release plate is now used as the DEC body.  Given a carefully balanced setup, it's operable even at 960mm with ease.  I'll settle myself with that at the time being for another ballhead does not help for minor adjustment, careful balance is even better!

This short imaging session is also to test my newly DIY reducer lens, and the results can be shown as below:

This is a mosaic of two frames.  I believe that I can adjust the position of the reducer lens in the optical chain to allow one shot full disc like before.

I've fine tuned the polar alignment with a good quality compass and an inclinometer application running on my wife's Android phone.  With 2x, hand tracking was easy with minimal vibration and the polar alignment seems of good quality:

The bigger group is AR1374 and the smaller group is AR1375.

After this brief solar imaging session, I began to investigate ways to make a better reducer to get full disc without stitching mosaic.  I've attached a small binocular objective to a generic blue filter by using those instant glue and the result seems great!  Even the built-in focuser of my Ranger could reach focus.  Here's a snapshot of the sun through glass window:

It's not calcium K but just a general blue filter as below:

The lens edge could be blackened to further improve the quality.  Now, I only wish to have a Baader 3.8 solar film for my Ranger so that I can do high power at better quality!

Sunday, December 11, 2011

20111210 Total Lunar Eclipse

With the excellent weather forecast, it's a must to go out.  Lunar eclipse does not require a dark sky but a darker sky will pay off since you can capture the (much dimmer) moon in front of the starry sky which is impossible except during lunar eclipse.  But life always means trade off, you have convenience and family, and better skies, and I chose the former option.

As planned, I went to a nearby playground to setup my gears.  It's around 10 minutes walk from my home and the view is proven since the last partial solar eclipse.  I went there first after having dinner with my family at around 8:20pm.

Then my wife and my kids arrived at around 9:00pm and then a couple of friends came a bit later.

Some snapshots taken during totality:

And finally an eclipse sequence, please click to enlarge:

Friday, December 09, 2011

Total Lunar Eclipse Observation Site

Last night I went out jogging as usual but it was a planned one.  Jogging aside but checking out the site on spot was the real purpose.  You know the moon travels along the sky and the exact path is not difficult to predict but then it's not always easy to predict whether it will be blocked or not especially with all those trees and buildings in sight.  To put it short, I've found a perfect spot near my home.  And I've been there before for the partial solar eclipse around two years ago:

 This map shows how to get there, nearby landmarks were Nam Cheong station (西鐵南昌站), Metro Harbor View (港灣豪庭), etc.

And the exact spot where I will be observing.  Inside the playground, you will see a path where you could go up, and I will be up there since it will clear up all the trees.

For the eclipse detail, see here:

And as from the timing chart, you will see that we won't detect major changes until 20:45, so I guess that I won't be there until 20:20 and totality will be around 22:31, and I won't stay late unless the sky is suboptimal such that I'll need to catch every chance.

I will take my tripod on a manual tracking mount,  a small telescope (my only one now), a pair of binoculars and of course, my camera.  You will see an interesting eclipsed moon at first and then a deep red moon hanging up there if sky allows during totality.

If we miss that opportunity, we will need to wait until 2015!  This year we have two of them but the last one was not well observed due to the poor weather.

You are welcome to join me, but please call me to confirm whether I'm there or not.  I might go somewhere else to get good composition with some interesting terrestrial targets.

Updated 2011/12/10:

The weather was getting nice and we have a blue sky now!  I will finalize my equipment line up like this:

1. Gitzo G106 with Manfrotto 410 head (skip the Mark-X)
2. A long mounting plate for both my Ranger and my camera
3. A simple DC of my daughter
4. Canon 10x30 IS

I've removed the JMI NGF-CM from my Ranger and use the original focuser to ease my load, 2" wide field  is not required for lunar eclipse.