Tuesday, July 15, 2014

20140715 Saturn

First time doing planet with my Nexstar SE mount.  Seeing poor at 2/10, transparency also low at 4/10, I believe.  This is done with my white C5 at f/20.

At 1/15s, gain was pushed to 80% which indicates poor transparency.

Visual observation with a 20mm eyepiece renders a solid image, but pushing to 125x by adding a 2x barlows, image becomes a bit too dim.

Tracking is very nice, however, the initial alignment is a bit difficult inside home given a narrow view angle from a small window.  Given the alignment is done, GOTO is rather accurate as I can quickly go to the Mars even at 62x!

I will do it again soon whether the sky gets better.  Saturn is quite nicely positioned this year.

Saturday, July 12, 2014

20140711 Moon, mount testing

This is yet another test of my Nexstar mount.

A table top mount is good in the sense that it can aim higher since it's lower!  And without the tripod, it could get closer to the corner to gain wider view.

This is a testing shot at 2400mm prime focus to see whether the tracking is good enough or not.  So far I'm satisfied, even with solar system alignment with the moon alone.

Thursday, July 10, 2014

Celestron Nexstar 4/5SE mount

I got one used without the tripod.

The first impression is good.  The mount is mostly metal, it's stable and the capacity is good.  I bought it down stair to try it out on the road side.  I just placed it on the road side.

GOTO is accurate even with solar system alignment, i.e. I pointed it to the moon and let it go!  Going to the Mars is fine enough, Saturn was blocked by a lamp post.  But the general direction is correct.

In order to see whether it was stable or not, I plugged in a 4mm eyepiece to check with the moon.  Focusing was easy, image was stable within one or two seconds.  Tracking was smooth and no shaking...  Later I realized that it was 312x!

People said this mount is better with the 4" Maksutov than with a 5" SCT, but I found that it's enough!  This mount will be used for solar imaging with my Ranger, so I consider it a nice purchase.


On the next night, I tried to use for my solar setup.  Yes, I did it at night.

The Solarmax filter makes it seriously front heavy, I've to slide the balance plate all the way to the other side to reach proper balance, but then the rear side will hit the mount base when the scope was pointing up. 

I guess I will need to add some weight at the rear side for balancing.

Monday, June 09, 2014

20140609 Sun taken through window glass

The window was broken so it couldn't be opened, I was forced to take image through the window glass:

The result was so ugly....

Monday, May 26, 2014

20140526 No tracking solar imaging

The Sun is still in a bad place from inside my room, and it is impossible to use my Mark-X for tracking.

1436 (GMT+8), at prime focus, no tracking and thus shifting and expand during stacking:-

1438 (GMT+8), with 2x barlows, no tracking and again shifting and expanding during stacking, the zip-zap line on the bottom is the artifact:-

I will try to keep on imaging even no tracking is possible.

Monday, April 28, 2014

20140428 Sun

Let's show the result first.

First one taken at 1514 (GMT+8) at prime focus:-

Next one close up at 1518 (GMT+8) with 2x barlows:-

I didn't look at the sun for long in H-alpha, and I didn't do imaging either.  And this is the first time I got my hand on the RichView tuning.  Seeing was very bad at 3/10, cloud moving around rather quickly with variable thickness.

Problem One: I couldn't use my Mark-X since the viewing angle was very bad, so I was using hand tracking or better say without tracking.

Problem Two: The new Solarmax is very front heavy, due to its bigger size and the added RichView tuning ring...

Problem Three: My DIY dec motor was not working for some reasons, I got to check.

Problem Four: I don't have a motorized focuser right now... 

Anyway, the result is rather encouraging.

Thursday, April 17, 2014

C5 First Light: Collimations!

Guess what, I spent over 1 hour for fine tuning the collimation. 

I first use a low power eyepiece, defocus the star and adjust.  Next, I put in a high power eyepiece, again defocus and fine tune the whole thing.  Finally, I put it in focus and check the airy disc, fine tune again.

Next I put in my Lu070M, and re-adjust the whole thing.

If you got a SCT, the first light should be on collimation!

Accurate collimation is critical, while some collimated scope is not really stable since not all the collimation screws are tight.  So, once you reached a good collimation, tighten each screws incrementally until it's rather firm in place, don't over-tighten, however.

This is also a good test for my DIY DEC motor, backlash is rather bad due to the poor motor mounting and there's no backlash compensation in the DIY hand controller, however, it's very useable.  At high power, after adjusting the collimation screw, the star will simply move away rather significantly, sometimes even out of the field of my 1/3" CCD, but then a dual axis motor will help to bring it back effectively.

My 4th C5 OTA

Believe it or not, this is my 4th C5 OTA.

I bought a Nexstar 5 and used it for quite long, and then I sold it after getting a 4" ED refractor or something like that, but I was soon caught by the portability bug.

I bought another Nexstar 5 OTA, and it was a lemon, I sent it back.  And then get another one, but soon sold due to financial reason shortly.  After a few years, I got this one, and this is the classical white OTA.  It's made in the US, the visual back has a single lock screw.

Collimation was very well maintained, only minor tweaking was what required, I will fine tune it further with a star.  This is a nice balance between portability and aperture at a very reasonable price, it's so unique.