Wednesday, August 31, 2016

Motoring the DEC axis of Sky Adventurer







The first working version is finished...


Monday, August 29, 2016

A new budget notebook

My Asus Eee has been repaired several times, I've replaced its keyboard, hard drive, battery and even CPU/chipset fan.  The transformer is dying so that I could use it either to charge up the battery or to operate the computer but not both, otherwise, the computer will reboot itself randomly.  Worst yet, it is still running Windows XP and would be obsolete enough soon, for example, no more dropbox in the near future.

So I took the plunge to buy a new notebook, but I was on a budget.  I want something light and small, despite I could use my Teclast tablet when I want absolute portability.  Finally, I got a Acer Aspire ES 11 which features a bigger display, and it's lighter in weight and has better battery life.  USB 3.0 port is available as well, but of course, it won't be much faster.  This is a fact of life, you choose only two: cost, performance, portability.

I have installed everything there so that it would be my next work horse.  ASI 120mm and 120mc drivers were installed,  that megapixel monochrome camera too!  No more dropped frame with the all the cameras.  So nice! 

Friday, July 15, 2016

20160715 Sun

Got a half day off today with the kids, found that the sun could be seen from another room with a less desirable angle, anyway, why not?

Pull out everything and went to another room, the view was a bit blocked but still do-able.  The JMI focuser controller is oh-no, low battery and cannot move at all.  Removing four screws and replace the battery is time consuming, the sun was going away.  My Teclast was low battery, too, just 7% left... what's bad is that, I couldn't charge it and use the USB port for my cheapy bw cam at the same time... So, I took the plunge and do it all without all those adversities.


Click for full size, taken at 0724 (UT)... T-max does not tuned well, aligned with only a single point, i.e. AR 2565.  I had just ordered an ASI 120mm (again) in the hope to get better image, let's see.  Why I was selling that was due to the Newton's ring, and my current bw cam got Newton's ring too...

Saturday, July 09, 2016

Motoring the DEC axis of the Sky Adventurer mount

Found suitable gears and motor, installed them right away.

Step one: try to find the suitable location for the motor for correct gear meshing, fix it with a tape:


Then, use some instant glue to fix it in place, add hot melt glue to further reinforce the position.


Finally, solder cables and also standard jet for connection to the controller box.  Add hot melt glue to insulation the bare end of the cable.


Done. 

A short clip before the soldering work to show the gear meshing:

Sunday, June 26, 2016

Enhancing the Nexstar mount

Last time I pulled the whole setup to a nearby playground, I managed to put the OTA, the tripod and every accessories inside a medium sized backpack.  And the Nexstar mount was placed inside another bag.  It's very portable indeed.

The backlash has to be adjusted further for high power imaging. 

For the power, I used 8 AA rechargeable batteries, and it gives ~2400mmAh at around 9.6V, after playing for around two hours, I guess only 50% power was left.

I've tried to fit 3 pieces of 18650 inside the battery compartment last time, and it's even smaller than 8 AA!  So I took the plunge to remove the original battery box and replace it with a 18650 battery box.

With higher quality 18650, say 3400mmAh (measured by myself), now I've 3400mmAh at around 11.1V so it should last even longer.  With my current charger, I could recharge them at once, instead of two times (i.e. four at a time), and it's much more efficient, too.  The cost of the 18650 is similar to AA rechargeable, by similar, I mean the cost of one piece of 18650 is similar to that of the cost of one piece of AA rechargeable!  So, the overall cost is less than a half.

And it's lighter too!

 
The modification is simple and even reversible, just some very simple soldering work.

Friday, June 24, 2016

20160623 Nam Cheong Playground Planet Imaging Night

I had virtually stopped planetary imaging after the shut down of my home@walnut observation point inside my home.

Tonight, I pulled out my C5 with the Nexstar mount to a nearby playground for planet imaging.  While most people were jogging (I use to jog there too), I took a seat on the grass and started imaging.

I feel like an idiot since I spent long time just to center my targets enough for imaging.  I still remember that I could do imaging with my C8 at f/50 but now I found a hard time using my C5 at f/20!


This is my mobile imaging station.  There is a tiny Gitzo G106 below, and a small projector metal plate to support both my Nexstar and my 10" Teclast Windows 8.1 tablet with a keyboard.  It won't be very stable as expected.

Transferring huge AVI files for imaging processing is slow.  My first target was Jupiter but then the processing of Mars was faster.

1345 (UT), this is stacked without further processing basically.


1347 (UT), this one is aggressively processed but it does not help much, maybe even worse... anyway.


Both taken with my C5 with a Tele Vue 2x barlows.  Without a IR blocker, the image is no good as expected.

Jupiter C5 at prime focus, 1308 (UT):-


With 2x barlows, 1319 (UT):-


Much worse than what I could do previously with a C5, I shall practise more.

Wednesday, June 15, 2016

Potential power source for the Nexstar mount

I had been using 3 pieces of 18650 in parallel to provide power to my Nexstar mount via the external power socket.  The internal AA battery compartment is also used as a backup source.

Last night I tried to pull out the AA battery compartment and I found it easy, it was just fixed there using double side sticky tape.  I tried to fit in my 3 pieces 18650 battery pack there and it has more space than enough, and such a modification is easily reversible too!






It even has enough space for a electrical coupler and thus no soldering required.  I'd love to find/make a replacement battery cover after the modifications.