Friday, October 02, 2015

20150929 Sun (very poor sky)

Just stacked, and a waste of time to further process.

1524 and 1525 (GMT+8), prime focus.  ASI 120MC.

Tuesday, September 29, 2015

20150928 Sun with ASI 120mc

Yes, you read it right, and I'm using a color camera to do H-alpha since my monochromatic LU070M was dead.

This frame shows the problem, the bayer color matrix ruins part of the resolution... 

As a work around, I downsize the images and here are the results:-

First up is a prime focus shot, taken at 1539 (GMT+8):-

Next is an overexposed prime focus shot, at 1542 (GMT+8):-

We have a huge prominence stretching all the way out and go back to the solar limb, what a sight!

Finally, a 3x close up:-

which is the downsized frame of the very first image of this page.

My Lu070M is dead

Today I found that my Lu070M is dead, I try to fix it but in vain.

Computers could still detect its presence, its serial number is shown too.  But then the captured screen remains all black, not even noise was shown.

I wonder if I should buy a ASI 120mm again or to let the Solarmax go.  I'll wait to see if I could find something good and cheap, first.

Meanwhile, I'll use my ASI 120mc at the time being.

Wednesday, September 23, 2015

Australia trip first shot 20150807 Gold Coast Surfer Paradise

This is a simple shot from the balcony of the hotel room:

Note the Omega globular cluster!

I did take longer exposure, but it didn't help much, so this one is left as a record.

A clean sky is half way to success, it's bright there but you could still do something.

20150923 Sun

Cloud moving around, so I only managed to get one single shot as below:

1400 (GMT+8), prime focus, i.e. 480mm.

Thursday, June 04, 2015

Teclast x98 Air

It's a Chinese Windows 8.1 tablet, featuring a OTG port.

I have tested last night, ASI 130mc could be used without problem.

However, Lu070m failed probably due to insufficient power from the OTG port.  A powered USB hub should work, but I got to test again.

This could be perfect for webcam imaging and guiding purpose.


To give a little bit more background, it features dual boot so you could choose between Windows 8.1 and Android 4.4.4 during startup.  There is no hot swap between two systems unlike some other Chinese offerings.

The 64G storage was split around half-half, with the Windows side having slightly more memory.  After installation of Office 2013 (bundled for free), SharpCap, ASI and Lumenera drivers, Stellarium, ASCOM Platform, PhD Guiding, BibleWorks, VLC player, Dropbox (occupying around 6G of space), I got around 9.5G space left.

I will need a buy a fast 64G micro SD for image capturing.


Installation Notes of ASCOM platform:

It required .NET 3.5 but Windows 8.1 has .NET 4 instead.

When I try to install .NET 3.5, the system refuses to install and after applying all the Windows Update, it success... but then it eats up a few gigabytes too.


Finally, I bought a 32G SD with 48M/s speed.  I will try to use it solely for imaging purpose, and upon capturing, I can take the card out, and process the files from my PC.  32G ought to be enough for one or two imaging sessions.

And then I also bought a OEM bluetooth keyboard and mouse, to be used with the tablet.  It's nicely designed so that it makes the tablet notebook like!  Best of both world, a small portable notebook, a tablet which can run all my astronomy applications, guiding, image capturing, processing, plus the android side for daily work.  The added bonus is the capacity to run Bible Works!


To further simplify the whole thing, I've bought a OTG cable which allows direct connection to the camera:

Friday, May 08, 2015

Final form of the converted Canon FD 300mm 2.8 in EOS EF mount

This is the adapter used. It consists of a 77-58mm step down ring, and then a 58mm focusing tube, plus a 58-42mm step down ring. The flange distance is then adjustable to suit different situations.

A 58mm tube is used instead of a 42mm tube which I previously acquired, to avoid any vignetting.  A M42 to EOS EF ring with electronic focus confirm is used, it is glued together to ensure proper orientation of the tripod socket. 

Thursday, April 30, 2015

A large piece of glass!

70mm refractor on the left and 300mm f2.8 lens on the right... as an amateur astronomer, we all love aperture!

My very first autoguiding exercise

The Sky Adventurer has only single axis guiding, so it would require good polar alignment to guide successfully... of course, it's rather hard to do indoor.

Finding a bright enough star is not easy too... but I managed to get one.  The polar alignment was rather off despite the target star stayed in the field for quite long, and that indicates not too bad polar alignment.  However, it did drift away slowly and PHD guiding was complaining.

Cloud moved in before I could try EQ Align to fine tune the polar alignment.

Now at least I know that my ASI 130mc and the ST4 port of my Sky Adventurer works, I will need a better night to try the whole thing again.

A small DEC motor was on order, together with some electronics, and I will try to make my Sky Adventurer with dual axis motor/guiding.  Not very confident, but why not have a try?


For dual axis guiding, the guide scope and the imaging scope  should be on the same side of the L adapter, so the balancing side should carry something heavy as well... is that making the whole thing meaningless in that case?  The Sky Adventurer is wide field and portable!

I guess I will be taking a 200mm lens for my trip, so the polar scope should be enough and no need of guiding.  So, I will be bring a 50mm lens, a 200mm lens plus a 2x tele extender and that's all.  The 300mm f2.8 will be left at home.


To test the concept of using camera lenses as guide scope, I found that I have to insert a 2x barlows in order to reach focus with a camera lens.  It's good in the sense that, the guiding lens is always working at higher power!  Suppose I have two lenses, 200mm and 300mm respectively.  If I use the 200mm as imaging scope and the 300mm as guide scope, the guide scope will be working at 600mm due to the barlows.  Even if I swap their role, the 300mm as imaging scope and the 200mm as the guider, but then the guiding side will still have 400mm focal length!

Wednesday, April 29, 2015

Sky Adventurer dual axis guiding

The Sky Adventurer features a ST4 style guiding port which allows RA guiding, but that also means it only correct PEC.  The DEC part is manual driven only, so we couldn't guide in a dual axis way.

Motorizing the DEC part is the first step, here we have two approaches:

The one on the left is to use an inline shaft coupler, I got one at home which matches quite nicely.  Problem is that, the motor would make the whole thing much more bulky.  The next method is the one on the right, it uses two gears, one on the original manual control knob and another one on the motor, but I got only one such gear ready at home.  I will need to buy one more and the motor could be placed below the DEC body, I will want a smaller motor in that case, and I will also need to find a way to mount the body and mesh the gear correctly.

The following wiring scheme could be used:

Guider -> 
ST4 port of my own, getting the DEC signal to drive the motor -> 
ST4 port of the Sky Adventurer

So no need to modify the Sky Adventurer, just add a "relay box" and steal the unused DEC signal.  A simple geared motor controller could be used to drive the DEC.  Too good to be true?  Best of both worlds?  Let's see... I shall start hunting for suitable parts.  We need gear with 6mm shaft bore.

Further downsizing: Skywatcher Sky Adventurer

This is a huge move again.

My GOTO Mark-X is very portable but yet, it requires a "heavy" 410 geared head, and it is rather heavy and bulky as well.  So here I go for an even smaller mount.  This mount should be able to do astrophotography and it should be able to let me use my C5 visually or for planet imaging.

First of all, the tripod that I'm going to use is a Velbon mini-white.  It is ultra-portable as you can see from the above picture on the right.  It can even sneak within a lens compartment of my Fastpack 350!  Next is the Sky Adventurer, the mount body could be hidden in a lens compartment of my Fastpack, too!  The polar wedge is lighter and easier to use than the 410 geared head, and again, could be fitted into a lens compartment.

This is what I have fitted within the lower padded compartment of my Fastpack 350 as shown above:

Upper left: Canon 50mm f1.8, plus a ASI 120mc for guiding.

Lower left: Skywatcher main body which is a self contained mount with hand controller and battery compartment, polarscope!  It even features an ST4 style guider port!

Upper middle: a Velbon mini white tripod, frankly, it's even more miraculous than the Sky Adventurer and they are also a perfect fit.

Upper right: polar wedge for the Skywatcher

Lower right: a Canon 200mm f2.8L

Also a Canon 70D with a 8mm fisheye lens

What's left is a L adapter containing also the DEC body on the upper compartment, and the notebook computer in its own compartment.  Too good to be true, right?  A simple backpack containing all the lenses, tracking mount with guiding, guider and camera!

The picture on the right is the testing setup.  It takes a Ranger without any problem and I would say a C5 is easy for this small guy with proper balancing on the other side of the L adapter.