Thursday, April 07, 2016

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 on the first hand.  Sounds quite nice.

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

Monday, March 28, 2016

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.


Sunday, March 27, 2016

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!

Wednesday, March 23, 2016

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! 

Wednesday, March 09, 2016

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...

Monday, February 29, 2016

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.

Sunday, February 28, 2016

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.