20161227 Sun

Cold front coming, seeing exceptionally poor from 0-2/10 at best... cannot properly focus.

0604 (UT) with a reducer, some nice filaments around but cannot go any higher power.

20161219 Sun

We finally have a small active region (AR2619) today!

Here is a 5x shot with a reducer (forgot to remove), note the dust on the CMOS, 0701 (UT):-

And now the full disc, 0655 (UT):-

20161216 Sun

Very poor seeing due to the cold front, no detail even with reducer:

0702 (UT), just a record.

20161213 Sun

Another day, my elder daughter was still sick at home, and I stayed with her.

1359 (GMT+8).

Sun 20161212

Another imaging session, but the sun was not very active so I only took the following full disc shot with my Ranger + reducer lens.

Gain was set to zero this time, 1338 (GMT+8):-

20161128 Sun

I don't know if this is the first time for me to use the ASI120mm, I had one before but sold shortly, this one was newly acquired.

First one taken with my Ranger with a reducer lens, 1245 (GMT+8):-

Second one with a 3x barlows, 2 frames mosaic... uneven illumination, long time no practice, taken at 1253 and 1255 (GMT+8).:-

After taking the images, I found that I didn't set the gain to zero and it was set at 50% which is very high.  No wonder why the result image is rather noisy.

I found no more Newton's ring even at 3x?

Motoring the DEC axis of Sky Adventurer

The first working version is finished...

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! 

20160715 Sun (and also 20160716, added on 20170916)

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...

--

20170916 Sun

I found that there is an unprocessed clip in my home NAS, and just did the processing and add it back.

Surprisingly similar to the one above, maybe the file name was incorrect?  But it was generated by Sharpcap...  anyway, just as a record.

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:

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.

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.

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.

Counter weight solution notes

Time to DIY something just in case...

The Star Adventurer has a M8 threaded hole, while my self adapted Mark-X has a 3/8" threaded hole on the other side....

I've a compact metal shaft with a 3/8" male thread, and 15mm diameter, no stopping screw or safety mechanism.

Just a note.

Field Power

Years I ago, I have a SLA battery which is powerful but extremely heavy, and then I made a bracket to use it as counter weight.

Later, I used 18650 batteries and it's much lighter.  And it's about as powerful as SLA.

Recently, I used USB power banks and it's even more compact in size, and it's airline portable too!

Problem is that, some USB power banks will stop delivering current, maybe they want some sort of hand shakes between devices.  I found a very old USB power bank which will keep on kicking with any load, and this is great.

The Sky Adventurer was now powered directly via USB, the Nexstar mount is powered via USB to 12V cable, and the GOTO Mark-X is powered via USB to 9V cable.  Very neat and portable!

GOTO Mark-X further modifications

It could be the only mount that I had, and could hold a bigger OTA!

I took the controller out, and modify it a bit to accept center positive power cord, and I could power it via my USB to 9V cable.  The current draw is about the same as it states, less than 200mA.  Funny is that, if you pause the motor, the current draw is maximum.  4X speed does not increase the power drain, too.

So, I also pulled out my Sky Adventurer base to fit them together.  I've used a simple tripod quick release base to match the 1/4" of the Mark-X, and it's a perfect fit.

No more need to use that 410 geared head for this purpose, this is also lighter and more accurate.  If I buy a strong tripod, plus adding a counter weight mechanism, it could take a C8, I believe.

Guess what, I always want a C8 after selling it.  But right now, I don't think I have the time and energy to have one yet, or otherwise, I will buy one immediately.

Nexstar 4/6 SE mount power comsumption

I bought a small USB power meter, and I sandwiched it between my USB power bank, and the USB -> 12V cable which is connected to my Nexstar 4/6 SE mount.

It was drawing 0.51A at 5.14V which is less than what I imagined.  When both motors were slewing at maximum slewing speed, it measures around 0.8-0.9A only!  Therefore, a USB power bank should be enough for a whole night of observation.

Fixing the Sky Adventurer

My Sky Adventurer was getting harder and harder to turn... it was kind of stuck even if you totally disengage the clutch, it won't turn unless you really force it.

On opening it, the problem was nearly shown, see below:

there was a circular scratch mark on the inner rotating axis!  Obviously, it shouldn't be there and it should be caused by some metal dirt or uneven machining?  So I cleaned up the surface and found a few small marks, they're so small that even if you touch them, you won't feel there's anything... I bought the finest sandpaper to sand those stuff down, and then put the inner axis in, rotate it a few times, and there are two dirty patch will form, and then I sand them down again and again.

Finally, they were gone.

You couldn't trust your finger, you won't feel it.  But if you turn the inner axis with it, dirt patches will form.  So after a few runs, they were all gone!

The gear was not machined very nicely, and I sand down those rough edges like the one which is shown below:

Placing some grease back (thank Eric Ng), and now it's very smooth!  The machining is not bad afterall, when I put the inner axis back even without grease, it feels like pressing a syringe! 

I'll them it along for camping and stargazing trip soon!

20160407 Sun (visual)

Thick cloud floating around...  so it's good time for testing my Canon 18x50 IS plus my newly DIY baader filters.

The rings were two 52mm-58mm stepping ring with 58mm male thread.  52mm is about right given the 50mm aperture of the Canon, and then 58mm would be perfect with the Canon, too!

The Baader filter was removed from my DIY filter previously for my Canon 10x30 IS... I won't use the Canon 10x30 IS for that purpose given I've the bigger brother.

Image stabilization works great, and I can detect the tiny 2528 without looking at spaceweather.com on the first hand.  Sounds quite nice.

Suddenly, I remember that I had used with Canon 10x30 IS for my total solar eclipse trip!

Removing all advertisements

There is not much earning possible with this blog.

Thus, I've just removed all the advertisements, inline or banner, links or whatever, in order to provide better browsing experience.

Enjoy.

20160326 Sun

The sky cleared up, with seeing 4/10 and transparency 7/10.

Sharpcap upgrades again from 2.7 to 2.8 this time, and it's apparently faster.

Taken at 0453 (UT), using the "skip mode", i.e. to skip some pixels in order to burst the frame rate at the expense of lower resolution:

Another one at 0523 (UT), using near full resolution (crop a bit), the frame rate is much slower, and it might result in some field rotations... a much bigger file (nearly 9G of data), but high resolution full disc shot in a single capture!

A new member

I always love my trusty Canon 10x30 IS, it's so portable and powerful... even its rubber coating was damaged by the DEET a few years ago.

I got a good deal recently on a Canon 18x50 IS!  I had always been looking for something like that, for example, I suffered from a broken Canon 15x50 IS before from ebay which costs me the return shipping cost and so much frustration!  Finally, this is a local deal which is about perfect!

IS works very nicely and with the higher power and the heavier weight, I expect it won't be as great as the Canon 10x30 IS for the stability, but the added aperture, and the far higher power is going to shine!

Longing to use it in the field!

I guess it will be a great partner to be used with wild camping trips.

--

2016/3/27 night:-

The sky cleared up a bit with transparency 3/10, I picked it up for some scanning from inside my home.

I saw nothing when I pointed it to the muddy sky.  However, after engaging the IS, stars popped up from the view, and the stars are pinpoint!  I could see the subtle color differences between stars, but then there is no chromatic aberration except on a few brightest stars, but I suspect they might be from atmospheric dispersion or effect of poor seeing.

I am pleasantly surprised by its optical quality.  High power scanning with image stabilization is just fantastic! 

20160309 Partial Solar Eclipse

My original plan was dull and boring, i.e. making high resolution H-alpha eclipse shots.  But the sky was so bad earlier this morning rendered this plan impossible.  So armed with my Canon 70D with a 100-400mm lens, and a 20 years old thousands oaks solar filter, what can I do?

I did a field trip yesterday night to see whether the location is suitable or not.

And this was how it looks this morning:-

Gave up? Not yet...

At 0814 (GMT+8), I first saw a hint of the sun...

Then at 0821 (GMT+8), it was even better

Soon I realized that I could take some images which clear sky would not allow, this was taken at 0844 (GMT+8),

Another mug shot at 0835 (GMT+8),

The sun was climbing up, taken at 0844 (GMT+8),

The sky was once cleared enough so that my filter must be used, taken at 0857 (GMT+8),

More shots with terrestrial object at 0920 (GMT+8),

Another one at 0922 (GMT+8),

The last one at 0954 (GMT+8),

Something that couldn't be done with great sky...

20160229 Sun

This is a special date, once in four years.  This is a special holiday for my daughter, and so I go out to have lunch with me.  So, I missed the normal observation time window.  By then, I can move my equipment cabinet in order to open the window of another side to capture the sun.

Using "skip" mode  which results in faster frame rate at the expense of lower resolution, 1539 (GMT+8):-

Using full size mode results in very low frame rate, but no need to do mosaic, alternative coloring scheme, 1546 (GMT+8):-

Teclast x98 Air 3G

A couple of months ago, I've backup the android partition and removed it.  The built-in drive is much faster than the micro SD (despite I've bought a faster micro SD) and therefore, much better for image capturing for the Sun and planets.  However, it has very limit space... in order to maximize the size, today I decided to remove all android related partitions.

To further free up spaces, I've mounted the micro SD to a NTFS folder and then moved the dropbox folder there.  So, I will have around 10G more space.

This is to prepare for the partial solar eclipse, as well as future imaging requirements.

20160227 Windy Night Pre-Collimation

After the arrival of the C5 Bob's knob, I installed them right away.  During the process, I found that the retaining ring of the corrector was loosen! 

Anyway, I installed the new collimation knobs one by one, and then remove the corrector altogether for cleaning.  To my surprise, the secondary was a bit fogged, and thank God that after some cleaning, it is shinny as new!  I removed the corrector entirely in the hope to find the original marker at the edge so that I could correct the (relative) orientation of the corrector.  Luckily, I found it!

Collimation with terrestrial target is not going to be accurate, so I just very roughly collimated by looking at the front of the scope, wishing that the correct was in proper location at the same time.

The sky cleared suddenly tonight, and I pulled out the Nexstar mount to do the collimation with tracking.  It is windy so I don't expect to do a full collimation but just a rough one, so that I could fine tune it within a few seconds before I do any imaging.

Pointing at the sky randomly, no star was shown basically no matter how I adjusted the focuser, and it indicates really bad collimation.  Swing to Sirius reveal a very ugly out the focus pattern, fine tuning the focus does not help but it shows an very asymmetric pattern, added with the turbulence generated by the poor seeing, I was a bit shocked.

Then I turned the focuser knob to a very out-of-focus position until the pattern was stable.  Adjust the collimation screw one-by-one, to know which screw corresponding to which direction.  After a couple of minutes, rough collimation was done. 

A good collimation is not just about correctness, but it is also about the even tightnesses of the screws.  The reason is that, if all three collimation screws were tight, it could hold much better than loose screws during transportation or even storage.  Therefore, I keep adjusting all three screws carefully, in order to tighten (not over tightening) all those screws.  Things were done within another couple of minutes.

I ended up using over 15 minutes in doing that.  Re-adjusting the focuser, the diffraction pattern is now much better!  Due to the poor seeing, for the most of the time, I couldn't see a nice diffraction pattern but then during moments of brief stableness, I could see it was quite nice.  Maybe even enough for imaging too.  I also found that background dim stars are shown.

When I was about to call an end to the task of tonight, I do a swing to M41, and it was shown very nicely.  I guess only a very minor touch will be required next time when I want to do imaging.  Last time the Jupiter imaging session was in vain both due to poor collimation (but I got no screw driver with me), and mis-orientated corrector, and now they were all fixed.

20160209 Sun

AR2497 and 2494.

Pretty good seeing, 1428 (GMT+8).  T-max tuning could be improved, however.

Bob's knobs ordered for my C5

Went out last night for Jupiter imaging, setup everything but found that collimation was off!

Too bad that I forgot to bring a screw driver.... no way to tune!

So, I ordered a set of Bob's knobs! 

I was tempted to buy compatible screws, but then I feel that I need to respect the original inventor!

I found my newly bought small camera bag could fit my C5 and the Gitzo G105!  The zipper pockets could hold eyepiece too!

I'd keep my C5 therefore.

--

Some day-back records:

A few days ago I took some solar images.

Two nights ago I went out for visual observation with my Canon 10x30, but then nothing could be seen except M42 and M45... M35-38 failed, M41 was suspected.

Last night was the Jupiter imaging session, failed badly.

20160125 Winter Sun (冰天的太陽)

Armed with a new focuser together with a clear sky, there is no reason not to shoot.

It's record breaking cold in Hong Kong, at 3 degree Celcius and strong wind, it's not bad to be able to shoot indoor.

First up is sun taken with crop mode, note the Newton's ring... 1403 (GMT+8):-

On using full chip mode, I could drift the sun around while capturing and that effectively remove the newton's ring, it's also much higher in resolution.  1407 (GMT+8):-

Click for full size.

A little adapter designed and 3D printed by a local buddy Jack Wong

The Skywatcher Sky Adventurer mount has a small polar scope illumninator, but then it has to be taken off before attaching the dovetail rail or a ball head.  It is not very convenient in the sense that 1) when the mount was moved accidentally, polar alignment could not be done without taking off everything 2) when attaching the telescope or camera, the setup might moved and then polar alignment has to be redone.

To solve this problem, a local buddy designed a small orange adapter and then 3D printed it so that the polar illuminator could be attached to the dovetail rail!