Tuesday, August 22, 2017

20170821 Sun

Didn't play H-alpha solar imaging for quite a long time.  A typhoon is coming and the air is extremely dirty, cloud were floating around and thus the imaging window is short, I couldn't even take a full 900 frames AVI.

Just a record:


0710 (UT), at the center is AR2671.

Taken with my Ranger, Solarmax 60 with BF10, ASI 120mm with a reducer lens in the BF10.

After this imaging session, I've removed the encoder assembly from my JMI DRO focuser, it's just too bulky and I don't need to DRO for solar imaging at all.  Anyone interested in that assembly with the hand controller can contact me.


Wednesday, July 05, 2017

20170704 Jupiter

Very poor seeing after a small thunderstorm, so just to test the new motorized  focusing solution.






1247 (UT), C5 with 2x barlows... the direction of the wind could be seen easily.

My Teclast has its bluetooth dead, I have to use another notebook for image capturing.

I've tried to use a USB hub (powered) to add a bluetooth dongle plus the ASI, but then it won't have enough power to drive... I guess the powered hub is not really powered.

C5 motorized focusing

The Nexstar mount is not something very solid, and on focusing, the image will shake.  Motorized focusing is a good solution.

I believe a few pictures are better than words, basically, this is a N20 type DC geared motor, plus pulley and belt.





Here is a short video to show the end result, also to demonstrate the backlash of the system.


I will probably add a pulley on the focuser shaft to provide a better coupling.

Sunday, June 11, 2017

20170610 Jupiter

Transparency 7/10, seeing 4/10.

C5 with 2x barlows, ASI 120mm


1412 UT, I've aligned by Rigel with the C5, hopefully will make future alignment faster.

Still wonder if I shall keep a C5, or go for a smaller refractor?  I don't know indeed.

Tuesday, June 06, 2017

20170606 Home@Walnut Jupiter

Cloud come and go, it's just crazy to do imaging like this:






I waited for so long just to align the mount with Jupiter.

I waited for another cloud gap for *brief* collimation.

And then I waited very long to capture a prime focus one, taken at 1401 UT:-


And then I realized the cloud amount was reduced, so I wait to capture with a 2x barlows, taken at 1410 UT, no more detail could be shown:


Moving cloud could imply poor seeing.


It's far more comfortable to shoot indoor!

Thursday, June 01, 2017

A new project: resuming Home@Walnut observation

It's raining today, and thus it's probably the end of the three consecutive clear nights.

Last night I setup my Nexstar + C5 in the old location where I observe indoor, and it's workable.  So, I should begin the migration, i.e. to move all my gears there.  I shall move one of the plants to my office, and then the rest of the plants will be placed on top of the dry box.

Another project is the motorize the focuser of my C5.  Previously I was thinking to sell it, and replaced it with my modified FD 300mm 2.8, but then it's no good at high magnification and so I will keep my C5 and further enhance it.

Tentatively, I will use one of those small motors, add brass gear on the focuser, and then drive it like the Sky Adventurer.  Let's see.

Wednesday, May 31, 2017

20170531 Home@Walnut testing of the 328

I did the final modification by introducing a short back tube of 2" diameter, it was fitted exactly from the rear lens of the 328 and the 1.25" adapter.  So, if that could not eliminate the internal reflection, it is then the intrinsic issue of the 328 optical chain, nothing to do with my modification. Therefore, I call it the final modification.


That tube looked really dark.....

The first test was conducted visually with a Canon 2x extender before a 1.25"diagonal, plus a 20mm eyepiece.  The resultant focal length should lie between 600mm to 900mm.  That is effective magnification of 30x to 45x. 

The moon is very contrasty and sharp!  Free of any false color, so I am encouraged.

Here is the first shot:


It seems okay, but the experienced eyes will know there is something wrong.   Adding a 5x powermate confirms that it sucks:






The contrast is very low, a signature of internal reflection.

Later on the same night, when Jupiter reached my window, I tested and confirmed that internal reflection was reduced, but it still exists,virtually no detail could be detected.

That modified 328 should be reserved only for imaging of DSOs.

Tuesday, May 30, 2017

20170530 Dragon Boat Festival Imaging

Again, I went back to that playground last night.

No wind tonight, better seeing... I guess around 6/10.

I setup the Nexstar in the wrong direction, I thought it will work, but then it fails to track properly, in short, it tracked with exactly opposite direction.  I believe two points alignment would do, but since I do only solar system alignment, so it won't know unless the initial position is fixed.

At first I guess there might be something wrong, and I redo the alignment but things kept on wrong.  Finally, I reversed the mounting direction of the tube, and thing got right by then.

There were no visible bright star on the sky due to the heavy light pollution, so I don't have any good target for collimation, I couldn't use high power diffraction pattern on dim stars.  So I just randomly picked a star, defocus a bit and collimate briefly with it.

I setup my scope where there were many flying insects, and my head was buried in the plants during alignment, so bad.  So I really have no mood on doing good collimation or focusing.

Moon at prime focus, 1319 UT


Jupiter with 3x barlows, 1330 UT, 150% resized


Jupiter at 1330 and 1332 UT, C5 with 3x:-



Nexstar mount, C5, 3x GSO barlows, ASI 120mc camera with my trusty and cheapy Teclast tablet.

Monday, May 29, 2017

20170529 Short imaging session


Quite windy these days, so I brought only the Ranger for this fun imaging session.


The moon is setting, so this is just a prime focus shot, taken at 1222 UT.


And we have a 2x shot, of the Jupiter, taken at 1228 UT.


Finally, push up to 5x, i.e. 2400mm focal length, taken at 1236 UT.

Using the Ranger is much easier for this Nexstar mount.

Thursday, May 18, 2017

Further testing of the Canon FD 300mm f2.8L in scope mode

I have done some work on the internal reflection issue before, but no testing since then.  Today I have a cloudy afternoon and thus it is a good chance to test it out with a EOS 1.25"adapter.

First test was conducted with a diagonal. Yes, it won't focus unless I add a barlow in front of the diagonal or a 2x extender, 2x extender seems more elegant.  In short, it's sharp with my 20mm eyepiece.  I expect around 50x with this configuration.

Pulling the diagonal off should be a better test, it's even sharper since the effective focal length could go down to 300mm!  I took the plunge to use it at 3000mm, yes, 3000mm by using a 2x extender plus a 5x Powermate, and so we have 150x and it remains very sharp and contrasty, too.

I guess I should try it out with the moon or the planets, probably with a camera.  I hope it could replace my C5 eventually, if it is also good as a 4" refractor.

 --

After writing the above short report, I pulled it out again to try higher.

First test was with 2x extender with a TMB 4mm, so we have 150x again.  Sharp and no image break down.

And then I added a 2x barlows in the same setup, so we have 300x!  Floaters come in but again no image break down, focusing was easy.

I'm quite confident now.


Thursday, April 27, 2017

20170418 Jupiter

The sky has been cleared for a few days, and I finally cannot hold myself but to have some simple imaging time.

I placed the Nexstar mount plus accessories into a small backpack and hand holding my C5, heading to a nearby small playground.


I just set the scope up like this, to save the effort about dragging the tripod out.


The Nexstar mount has quite some backlash and the backlash compensation was not fine tuned enough, keeping the Jupiter in the field is not easy...


The collimation must be very bad.


Here is the result after processing;


And this is the prime focus shot, those with a barlows were too bad to show.

Thursday, April 13, 2017

Minor revamp of the Canon FD 300mm f2.8L

I removed the ugly hot melt glue and replaced it with eproxy putty.  I might paint it back later.

I tried to compare the focusing chip which utilizes the phrase detector, with the live view and the result is consistently effective and accurate.






And then I set it up on the Sky Adventurer, and it supports well, and the counter weight is far more than enough.  Both the internal RA motor slews well, and my DIY DEC motor works well, too.





You can also see the Polemaster above.

Really want to try it out under than stars.  I have several prime lenses,  a 8mm fisheye lens, a 50mm f1.8, a 200mm f2.8 plus this 300mm f2.8, and that should be enough for quite many targets.

Thursday, March 23, 2017

A smaller focuser controller

I have a dead 18650 charger, so I removed all the circuit board inside, solder two small switches on the top to make a small focuser controller for my JMI.


It's powered by a 18650 inside, I could even add a small rheostat inside to adjust the speed.


When I don't need to DRO control unit, for example, like for a more compact setup like visual trip, this small controller could be used.

Wednesday, February 01, 2017

20170201 Sun

Cloud keeps moving around today, seeing 5/10, transparency 4/10.

Don't really have time to fine tune to focus or the T-max.


0706 (UT), with reducer:


0710 (UT), with 2x barlows:-


0711 (UT), with 2x barlows, that interesting filaments attracted my eyes:-


The last image really shows how poor is the T-max, very uneven bandwidth across this little frame.

Friday, January 27, 2017

Polemaster and Sharpcap 2.9+

I went last night without any luck, the sky was too bad.

Tonight the sky seems a bit better, so I went again.  A nearby light polluted sky, with the polar region partially blocked.

Since I've tested with Polemaster software, and tonight I play with Sharpcap 2.9+.  If the automatic plate solving works, it's simpler for the Polemaster software requires manual pattern matching.

To my surprise, it works out very nicely!

Here's the screen shots of how it works... Plate solving success...


And then rotate along RA, success again... 


After polar alignment with Sharpcap, I proceed with the software of Polemaster and it works!   Confirmed the alignment.


And then I removed the polarscope caps, saw Polaris in the expected position!  I hope I could do some wide field imaging soon!

Wednesday, January 25, 2017

20170125 Sun

Glad that we still have some sunshine today, seeing 5/10, transparency 4/10.

0652 (UT) with reducer:


0655 (UT) with 2x barlows:


Keep on going...

Tuesday, January 24, 2017

20170124 Sun

We have some brief clear moments today, seeing 5/10, transparency 5/10.

0711 (UT) , with reducer:


0717 (UT), with 2x barlows:




 

BTW, I'm switching my job and my new job will start from mid-Feb... so at the time being, I've more time to observe.

Monday, January 23, 2017

20170123 Sun

Let's keep thing as monochromatic as it should be.

Full disc at 0700 (UT), taken with a reducer.


 Close up of AR2628, with a 2x barlows, 0705 (UT):-


I have to push the exposure and gain really high to show this hedgerow, 0709 (UT), again with a 2x barlows.


Cloud moves around today, seeing 5/10, transparency 5/10.

Sunday, January 22, 2017

20170122 Sun

Seeing quite good at 6/10, transparency 6/10.

0706 (UT), with reducer, rather sharp and finer detail could be seen.


0714 (UT), with 3x barlows, Newton's ring persist as well as some dust artifacts, I did not drift around the image enough while capturing.


Switched to use AutoStakkert!

Wavelet goes back to Registax, and final touch with PS.

PoleMaster

I always said, there are three important basic techniques for astrophotography namely: collimation, focusing and polar alignment.  And in Cantonese we said: 對焦,對 pole, 對光軸...



For focusing, I have a motorized focuser.  For collimation, I bought the original Bob's knob for collimation.  And now for polar alignment, I have just bought the QHY PoleMaster!

To use it in the field, I use my Teclast tablet via OTG cable.  And it connects without any problem, I've tried it in day time but the exposure control is very limited so that even at its lowest setting, the screen white out.  Can't wait to test it tonight in a nearby location, I hope I could find a place where the Polaris is visible.

--

 I really got chance to try it out in the field on the same night.


I only got time to go to a nearby playground but then I don't know if Polaris is visible or not there... After more than half an hour, I guess I made it.  Note the bright thick line across was from a distant (not too far away) tower crane!  The Polaris is barely visible, and then light pollution was very severe so that pushing the gain/exposure further will only white out the whole screen.

Finding the center of rotation of the Sky Adventurer is not easy by pressing the button since it's just too slow.  And instead, I disengage the clutch and move it manually but this is not recommended as stated in the user manual.

Finally, I pulled out my DSLR and tested with my 50mm lens.  I stopped the aperture and set ISO low so that I could do a 3-minute exposure under such a sky, star remains pinpoint, good news.