Tuesday, June 21, 2011

The Samyang 8mm f3.5 arrived!

I've some paypal balance and I consider it better to buy something than to transfer it to the bank since the charge is high and the conversion rate is bad.

I ordered it last Thursday and it arrives today (Tuesday), so it's very quick. The seller does not give me a tracking number and I could find one on the package, so if they will send it to me, it's definitely better.

The items were well packed, but the lens cleaning set has some of its fluid leaked maybe due to the pressure from other items. The box of the kit was partially soaked and some of the papers inside the box was somewhat wet as well, luckily, the lens was not affected at all.

The brand name on the box was Rokinon but the manual has Samyang, so it's an OEM product. The lens was built like tank with tight tolerance. The focusing ring was smooth and the aperture ring snaps into place with clicks. Focusing was easy due to its huge depth-of-field even at f3.5. No focusing was required if I stick at f8 or something like that. The focuser is butter smooth, a feeling of high quality focuser, feel like L class lens. No joking!

The metering of my 450D tends to give brighter image, but then I found similar issue even with my telescopes attached. Simple exposure compensation (AV) could fix the problem easily.

I never played with such a wide lens and 10mm is the widest I tried. The huge field of view and the fish-eye effect was immense! I guess that I will need to spend a lot of time with it to get use to it. The first thing that I wanted to do was definitely a wide field imaging on a good starry night but then since a typhoon is coming, I will not have a chance to do so any time soon.

Monday, June 20, 2011

Observing with the kids

The plan is simple, the kids wanted to see the Saturn! Therefore, we don't have to travel but we can truly grab-and-go! I've my Ranger on Gitzo G106 with Manfrotto 410, I also have a 40mm Pentax SMC XL as a finder (over 5 degrees of view) and a 20mm Widescan (24x) and also a 5x Powermate (120x).

I was soon misled by Arcturus which is similar in coloration! Without much sky to deal with, I swing my Ranger around to point at Arcturus thinking that it was Saturn... it's nearly the zenith and thus I had a hard time to locate it. After fooling around for nearly 5 minutes, I managed to get it into the view... you know, using a 410 head suffered from the Dobsonian hole issue for target near the zenith. Got it but then it's nothing but a star!

Being cheated, I asked my sister to use her mobile phone to locate Saturn... we were surprised to see that it was partly hidden by the bright spotlights of a nearby building! I swing my Ranger there, immediately blinded by the spotlight but still, it's not hard to point at the Saturn. Pushing the power to 120x, the view was not affected at all.

The kids took turn to look into the eyepiece. I guess some managed to see, but some with doubt. I guess I should keep an easier eyepiece for the kid, like a cheap Plossl, since Widescan or even Nagler could be quite hard to look through due to their sweet-spot and blackout issue. However, the wider field of view should be nice for a non-tracked mount.

Sunday, June 19, 2011

20110619 Saturn

Last time I was capturing Saturn with a fixed tripod, this time, I used my TG-SP II in the hope to capture a longer AVI or even push the image scale further.

First of all, I setup everything with my Pentax SMC XL 40mm in place. I found the setup is too heavy for the original counter weight, so I've used the heavier local made counter weight and it tracks very nicely.

Saturn was barely non-stellar in this low magnification (12x). I balanced mount roughly and then I proceed to a 20mm Widescan since it's roughly parfocal with my Lumenera. With the visual view, I couldn't see any problem on the balancing but I doubt when it comes to imaging. Then I added my 5x Powermate into the optical chain and I soon realized the issue on balancing! The mount was not tracking well and the slow motion control was not working very well, either.

Since I don't want to re-balance everything, I replace the Widescan with my Lumenera and with some major effort, I finally managed to fit Saturn into the view but then I found it drifting like without tracking. I also found that this setup was a little bit too heavy for my Gitzo G106, maybe since I've a 410 head and a Takahashi wedge so that the center of gravity was higher than usual.

It's a failed attempt.

Anyway, I've still capture two clips, and the first one was at 7.5fps (i.e. 1/8s with medium gain) and the second one was at 15fps (i.e. 1/15s with high gain).

2158 (GMT+8) at 7.5fps:-

2159 (GMT+8) at 15fps:-

The lower power visual setup with Pentax SMC XL 40mm:-

The imaging setup:-

Note the large weight difference!

Saturday, June 18, 2011

Inventory Checking

I did something similar on November 10, 2010.


1. 70mm f=500mm achromatic objective mounted with 77mm thread
2. Tele Vue Ranger
3. Canon 10x30 IS

(1) is for sales at $300 HKD, useful as a great closeup lens for camera lens!

Eyepieces, Barlows and Diagonals:

1. Pentax 40mm SMC XL
2. Tele Vue Nagler 13mm Type 6
3. Tele Vue Powermate 5x and 2x Barlows
4. Japanese Widescan Type III 20mm
5. Japanese Ortho 7mm
6. Tele Vue 1.25" mirror diagonal
7. Chinese 2" mirror diagonal
8. Astrotech 1.25" dielectric diagonal

(8) is for sales, it's very new with box, $500 HKD.


1. Gitzo G106
2. Manfrotto 410
3. Takahashi TG-SP II

Camera and accessories:

1. Lumenera LU070M
2. JMI NGF-CM with Tele Vue Ranger adapter
3. Thousands Oak Type II+ for Ranger

(1) is available for sales, $2700 HKD.

Thursday, June 16, 2011

20110616 Total Lunar Eclipse

Woke up at 2:00am, the mount was already there in place, just need to put on the camera and it's done.

The above is my equipments: Canon 100-400mm f4.5-5.6L with Canon 450D, a timer release cable is attached and a USB cable was also attached for downloading images for Facebook update. The timer release is not very useful since the moon was blocked for most of the time. Takahashi TG-SP II was used for tracking and it's powered by the USB port of my PC through a DIY cable, it's just convenient! No need transformer, no need to charge any battery, etc! The whole setup was placed on my Gitzo G106 with a Manfrotto 410 head to fine tune the polar alignment.

I also have my Canon 10x30 IS for visual observation, I did something similar during the total solar eclipse in 2008 and I can observe with my right hand holding the binoculars and my left hand to press the shutter release.

While setting up my Canon 100-400mm, I took my 200mm f2.8 to have some handheld snapshots first since the cloud was getting in.

When the tracked setup is ready, things are much better. As the moon gets dimmer, we will need some form of tracking since you're doing several seconds of exposure. Originally I planned to do 800mm with a 2x Kenko but then the sky was very bad with thin cloud, so f/11 would be too much!

Cloud was moving around, thick and thin, large and small...

The cloud amount was increasing overall, so some cloud breaks could be as short as several seconds, so you will have to adjust the mount, etc. Spot metering was used, and so you will want the bright part of the moon to be at the center of the frame!

Friends from local amateurs were reporting their situations and some reported rain!

The weather conditions seemed highly localized, and later we found that we could observe far more in some lucky locations!

This is the last one that I managed to capture.

I waited more than one hour after this shot and we had heavy rain and wind.

Finally, I found the moon could be blocked by distant building before I packed up my stuff.

Believe it or not, this is the first total lunar eclipse that I managed to observe, but then I still couldn't see the real totality. Good me luck next time in December if I managed to catch a chance!

Tuesday, June 14, 2011

Tele Vue Ranger with NGF-CM

I've ordered a 2" filter thread extension tube for my 2" diagonal so that it could serve as a mini-drawtube which effectively extends the focus travel range of my transformed Ranger which has the original focuser removed and replaced with a short focus travel NGF-CM. Such a combination works with all my existing eyepieces from a 2" Pentax SMC XL to a 13mm Nagler with 2x or even 5x.

Previously my Ranger was used solely for solar imaging and since I used it with a reducer, so I really cared more on the in-travel. Now, it's my only telescope so I wanted to make it more versatile.

Now it's also capable for visual work!

Jogging under the stars!

Last night I went jogging at night as usual. In Hong Kong, you really couldn't jog under a lot of stars, but when the sky was clear, you could see some brighter constellations. It's refreshing enough to run, and the stars drift slowly along with time and so you know life is moving :-)

Monday, June 13, 2011

20110612 Moon

After the short and brief pass-by of a small typhoon, the sky was cleared except a thin layer of mist. The moon shines through the windows, casting shadow on the floor.

I picked out my Canon 450D, 100-400mm and a 2x to have some very brief observation and imaging on tripod. The moon was too dim (the mist was too thick!), so that exposure for the moon would be over 3s!

Anyway, the view through the finder is fine enough.