Wednesday, November 23, 2011

Updated: Various Accessories for Sales

Package deal: $999 HKD takes them all! 

One more item added (2011-11-25) 

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.


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.


A pair of felt lined 5.5 in (ID) tube ring with mounting plate.  (SOLD)



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".




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!



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


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


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.


My Astronomy Corner

This morning, while I'm looking at the window which is my astronomy corner, and it's now full of other stuff and plants, then I proceed to write the following.

Earliest stage: I was using my Tele Vue Ranger on my Gitzo G106 with Manfrotto 410 head.  I scanned around from the limited window.  I lived in the city center but it was an old factory area and thus, it's pretty dark at night.  In the days of good transparency, I could identify quite a number of constellations there.  In addition to my Ranger, I would also use my Pentax 10x50 PCF III.

Planet stage:  I was using virtually the same setup.  I acquired a Philips ToUCam and begin the work of hand tracking with a 5x Powermate!  Guess what, it's doable and I could resolve a number of cloud belts on the Jupiter, and I could resolve the Cassini division of Saturn as well!

Encouraged with these results, I was tempted to go tracked planet imaging.  I've conducted a series of feasibility test to see what's the biggest aperture that I could use.  I've tried a Nexstar 5, and I finally settled with a C8.  The C8 is a very big scope when used with an open window, but then I found a Giro mount with Tech2000 GiroDrive could do the work!  I considered it a huge success since I managed to capture the great opposition of Mars, and some nice moments like the double shadow transit of those Galileo satellite of the Jupiter.

But then my kid grew up and they would like to buy a piano, so I've to reduce in size since my astronomy corner has to shrink in size, there's simply insufficient room for me to keep those bigger gears.  In the hope to get better image, I sold my alt-az tracking Giro mount and replaced it with an equatorial mount (LXD55).  I have replaced my C8 with a C5.

With new imagers like DMK 31AF03, DMK 21AU04, DBK 21AF04... I could approach or even exceed the images taken with my C5 than my C8!

Solar stage:  Guess what, I was addicted to solar imaging and in particular H-alpha.  And I also got a fantastic deal on a second hand Solarmax 40.  On the other hand, I found that with my C5, I couldn't do much no matter how I squeeze but I found H-alpha imaging more or less undeveloped by then.

At first, I couldn't understand why my ToUCam H-alpha images were so bad!  But one day, a thin layer of cloud moved into the field of view and I then know there must be something wrong with the color camera.  I found that with my color camera, there're two correct exposures!  Then, I began to study the inside of the CCD and I found the Bayer color filter matrix was the problem!  Only 1/4 of the pixels were useful in H-alpha and thus, I ordered the b/w chip to replace for my ToUCam Pro!  Guess what, I've stucked myself with at least four or five ToUCam Pro in total, but they all suffered from premature death.  Blame me on my poor soldering skill?

I've found that monochromatic imaging would be the key.  Thus, I took the plunge.  I was among the very first people who ordered a DMK 31AF03 from a Australian non-astronomy dealer.  It gave me huge success over b/w modified ToUCam Pro due to its much better circuitry and uncompressed high frame rate.

With this success, I proceed to do imaging of the sun in Calcium K, and then I also did white light with a Herschel Wedge.  Those were really lovely memory.

Minimizing stage:  I've a very clear calling from above, so I quit my job and go for the seminary.  And after my graduation, my wife also got the same call and thus, In order to survive and to make myself "lighter" for any new challenges, I began to sell most of my astronomy stuff.  Right now, I only have my aged Tele Vue Ranger which no body would buy it since the lens was not in good condition.  I've sold all my solar filters except an aged Thousand Oaks Type 2+ which was filled with "millions" of pinholes.  I've even sold my TG-SP II which I planned to use for wide field imaging for life time.

Now, I may still do what I used to do in the early beginning and in fact, I still have more than I had in the earliest stage.  I am sure that I shall continue with this wonderful hobby.

Saturday, November 19, 2011

GOTO Mark-X Motor Candidates

The Tele Vue System mount motor arrived yesterday, it's a new one from stock.  I found the mounting of this motor to the Mark-X non-trivial and I probably need a machinist to help me out.  At the same time, I will need to hack the crystal to accommodate the speed difference:


And meanwhile, a Cloudynights buddy reported that another simpler drive could also accommodate 126T without modification, and the mounting could be easier as well.

In that case, the calibration of speed might be the hardest part, I will need accurate polar alignment and then I can adjust the speed, maybe with the help of my Lu070M.  However, it could be hard to have very accurate alignment without a properly tracking motor?  An egg and chicken problem.

So, I'll need to see which way I should go.

Thursday, November 10, 2011

Various Accessories for Sales

Package deal: $999 HKD takes them all! 

More items added but price reduced. (18 Nov 2011 update AGAIN) (21 Nov 2011 three more items and the same price)


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

First up 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.

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


Generic small Chinese ballhead, suitable for digital camera, ask for $50 HKD. (RESERVED for CL Chan)


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.


Celestron Nexstar mount parts, including both motors with encoders, also the gears.


Ask for $400 HKD, the motors alone should cost more than that.  And I got the following information from a CN buddy:

"These were used on the original Nexstar 5 and 8. The 5 and 8i used Lo-Cog Pittmans with different encoders. These things are available for about $275 each new.

The same early motor was used on the classic Meade LX200 16", although the gear reduction was 19.5:1. I was able to find a recent series 8000 Lo-Cog on eBay with the correct gear ratio and swap the gear heads to get the 19.5:1 ratio.

The Meade used a different encoder count too, so the HEDS encoder and the code wheel have to be swapped to use it on the LX200."


Motors were SOLD, gears were still available at $50 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!


You will one day want this tool, it's for creating threads and threaded holes yourself. Virtually new and ask for $50 HKD only (RESERVED for Simon).


JMI 2" -> 1.25" compression ring adapter:-


DIY 43mm male thread afocal imaging adapter:-


Never used JJC EC-2 Eyepiece Extender for Canon EOS DSLR:-



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.



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.


Wednesday, November 02, 2011

The Quest for a motor for my Mark-X

2011-11-18

The motor arrived in perfect condition, however, the shaft coupler is missing and thus I will probably need to buy one myself.  On the other hand, I'm delighted to see its quality, the buttons were very nice to press and the pin on the connector to the hand controller is just thick and strong!  I'll need to built a power supply for it, and the seller reminds me that it's center negative and it's running at 9V, and thus a 8AA rechargeable will be about right!

After verifying that the motor is indeed working, I shall find a suitable shaft coupler for it and also how to mount it to the Mark-X, finally, I will need to find a replacement crystal oscillator for 126 teeth.

2011-11-13

While waiting for the delivery, I've searched some potential oscillator suppliers:

Mouser, I ordered from them before, trouble free and good range of stuff

http://hk.mouser.com/Home.aspx

RS Online

http://hongkong02.rs-online.com/web/

2011-11-09

The motor and controller is now on its way to me, tracking number: LC308020755US

The seller was kind enough to tell me that the controller is center negative!  I should keep that in mind.  The first thing which I'm going to do is to put it on the mount, I guess that the shaft coupler will connect without big problem.  I shall see if the torque is enough and if I will need to improve the mounting stability, and maybe I will need a local machinist friend to help here.

Secondly, I will need to open up the controller to see how can I modify it from 180 to 126 teeth, I wish and I expect that it will be controlled by a crystal and than I can scale the frequency and buy a new one for it.  Exact matching might not be possible but I hope that it will be close enough for me to track like 5-10 minutes at, maybe say, 200mm focal length.

Found a scanned specification sheet of the motor/controller.  It has a part number of RMD-2401 and also a model number of CXD-1.  In the specification part, it was described as quartz stepping motor and thus I would probably be able to swap the quartz crystal in order to adapt it to 126 teeth.  The rated voltage is 9V and the allowance is from 4.5V to 12V.  It consumed 160mA and it supports clockwise, counter-clockwise, 4 times speed, and also temporary stop.

From the limited photographs, I believe it would be very easy to mount it to my Mark-X.

2011-11-08

I'll try to buy a Japanese Carton mount motor and attempt to modify it myself.  It's the same motor for the Tele Vue system mount which has 180 teeth, since it's a very old model, and I suppose that it will be controlled by crystal and thus, the modification should be relatively simpler for me since I don't need a EPROM writer.  Of course, matching crystal is another hard story and an exact match is probably impossible but for tracking like several minutes should be perfectly okay, at least I tend to believe so.  Let's see if I can get a good deal.

2011-11-05

There're some very cheap RA motor selling in ebay but the seller never response my request for shipping quote.  Not until I click buy-it-now, and then after a few days, I managed to get the shipping but it's 2x of the motor itself!  Of course, I will have to cancel it.

2011-11-03

If I were to use gear pairs to match the gear ratio, maybe I should use a off-the-shelf motor with controller rather than to build everything from ground up by myself?  At least it seems more reliable?

2011-11-02

I've two existing DC geared motor, it's rated at 5 RPM at 12V.

Tonight, I've tried to apply 2.4V DC to it and it runs, I did a very rough estimate and it's running at 1 RPM at 2.4V... Suppose that I have to get 0.0875 RPM, I will need to slow it down further by using a PWM controller first, and then I will be able to get 0.1 RPM.

To get 0.0875 RPM, I will need a pair of gear, for examples, 28 and 32 tooth gears as recommended by DAVIDG in cloudynight atm forum.


I've to check my existing gear inventory, and see what I should buy. 


I've a 35 tooth gear suitable for the motor, so I will need a 40 tooth gear for the worm gear shaft?


I've another 37 tooth gear suitable for the motor, so I will need a 42 tooth gear for the worm gear shaft?