20080927 H-alpha Sun (15s only!)

I have only 15s of continuous sunshine today after waiting for around one hour, cloud keep floating around, and to get surface detail in H-alpha, we need relatively cloudless... we can have some thin cloud moving, and to average them out by stacking, but then it's still unavailable today except this 15s. For prominences shot, I can push the exposure to pass through the thin cloud.

Telescope: Borg 45ED II
Filter: Coronado Solarmax 40 with BF10
Camera: DMK 31AF03

1336 (GMT+8), that 15s shot:-


1337 (GMT+8), exposure pushed to pass through the cloud:-


These two shots were taken with windows closed... so the glass is a killer of the quality, too... but for this kind of sky, don't worry.

20080926 Sun (white light)

Camera: Canon 450D
Lens: Canon 200mm 2.8L + Kenko 2x Teleplus
Filter: Thousand Oaks Glass Type 2+
Exposure: Spot metering/Automatic

Hand held, the sun was too low in the sky when I woke up (I was on sick leave today), no time to setup my H-alpha gear, and so I used the above setup to do a snapshot. Nothing apparently.

1652 (GMT+8) at ISO 100, cleaner but blurred due to vibration:-


1652 (GMT+8) at ISO 1600, noisy but shake free:-

20080921 Sun

Sunny day! Transparency is 6/10, seeing 5/10, the sun is still pretty inactive, but we got some QRF now, as well as a few prominences around.

Telescope: Borg 45ED II, close up taken with 2x barlows
Filter: Coronado Solarmax 40 with BF10
Camera: DMK 31AF03

1443 (GMT+8), a full disc shot, selectively pushed the prominences:-


1443 (GMT+8), promnences target shot:-

1445 (GMT+8), another prominence target shot, further pushed exposure to bring out those subtle and dim prominences:-

1446 (GMT+8), close up of the QRF, again selectively pushed the prominence which extended from this QRF:-

1448 (GMT+8), the close up of the prominence, quite fine detail could be seen:-

Not bad for these inactive months...

Family Stargazing

My sister drove us to the countryside to have a short stargazing session tonight. After around an hour of car trip, plus around 10 minutes walk, we arrived a relatively darker place, Tai Mei Tuk.

Originally I planned to take my LXD55 together with my C5, but then I changed my setup to my Ranger plus Manfrotto 410 head on a small Gitzo G106 trip. That really eases my load significantly! At least the 12V 7Ah SLA battery and the counter weight alone are huge saving!

The sky was not very clear, I would rate it as 5/10, with some cloud floating around, seeing was very poor at 2/10... Stars were not pinpoint even at 48x!

We observed Albireo, which was very lovely at 24x! Two very contrasty stars were seen with clean separation. We also saw Almach, but this pair was not as cleanly resolved as it was rather low in the sky, and that region was covered by thin haze.



My elder daughter is called Alby, which is derived from Alb-ireo, and then my second daughter is called Almy, which is derived from Alm-ach, that's why these two were our prime target! I see that Alby has a very beautiful smile after she watched her star(s) in the eyepiece! Too bad that Almy was sleeping at that time, or else she could see her own star(s) as well.

We also saw Jupiter and its satellites as well. I also describe the summer sky with a small green laser pointer to my daughter and my sister.

That's the end of the very short session, it's short, but very enjoyable and relaxing!

20080920 DSLR Sun

Again, the sun was sinking low. Borg 45ED II, Solarmax 40/BF10, first presented are some raw unprocessed (except cropping) shots:-

1726 (GMT+8), take with -2 stop:-


1728 (GMT+8), taken with spot metering:-


1728 (GMT+8), taken with +2 stop, resized to show the internal reflection plus the cloud around:-


1728 (GMT+8), cropped and pushed:-


1729 (GMT+8), blue channel extracted and processed:-

20080915 DSLR Sun

The sun was sinking low in the sky, and I got little time to focus and try exposure, so here's one of the best, only green channel is shown:

1614 (GMT+8):-

Borg 45ED II, Solarmax 40, BF10... Canon 450D.

Fisheye lens and Astronomy

I guess this title is a bit funny since this blog is dedicated to astronomy, so why I've to emphasis that? Please let me leave this question a little bit later, and let's have a look at my friend's result below:-

http://tuugii.blogspot.com/2008/05/center-of-our-galaxy-through-f18.html

As you can see, the result is just not bad indeed! Notice that it's not taken with a real fisheye lens, but instead, only a cheap add-on lens is used. This kind of lenses are more widely used for consumer grade digital camera rather than DSLR, for a real fish eye lens will produce far better result.

However, as you can see from the above, the result could be good enough. Okay, let's get back to the first question about the title of this entry.

If you plan to buy a fisheye lens for special effect, I guess you should go for a dedicated/real fisheye lens. However, for astronomy purpose, you don't have. Why is that? To use a fisheye lens on the night sky, you don't really have a lot of flexibility on the composition, I mean you can point your lens to one or two different location and then you already cover all the sky! Therefore, a fisheye lens will not stay in your camera for too long given a new observation location, and after one or two (how about three?) shots, you will want to switch to another longer focus lens. Even if you take a few more for stacking, it won't stay attached to your camera for more than around half an hour. To me, it does not worth to buy a far more expensive dedicated lens. Of course, if you got the money and space, you can always go for the best.

Canon 5D Mark II announced

It's finally announced:

http://www.dpreview.com/news/0809/08091705canon_5dmarkII.asp

http://www.dpreview.com/previews/canoneos5dmarkII/

I guess the most important upgrades are:

1. HD video capture: this is a very nice news if you wanted a more versatile camera. For those who have a family, and you will immediately agree that it's very important to be able to capture video clips but then it's also hard to bring another DV out.

2. Live view, larger screen and more pixels: but then these were not anything special

It seems like a must that one should upgrade after like two years or even shorter, but as an amateur astronomer, we might have a better upgrade path, for me, I will do like this:

1. Modify my existing camera to enhance its H-alpha performance
2. Buy a new camera
3. Sell the last modified camera

Make sense?

20080914 Mid-autumn festival

It's a traditional Chinese festival, I brought along my Gitzo G106, Manfrotto 410 head, plus my Tele Vue Ranger with my family.



This is my 3 years old daughter Almy, I guess it's the first time she really looked into the eyepiece. I did try to let her look into my telescopes before, but this time, she could really see it!

20080914 Sun

Nothing on the sun again, seeing like 3/10, transparency 3/10 as well, very foggy (dirty) sky.

Telescope: Borg 45ED II

Filters:

Solarmax 40 with BF10 for H-alpha
APM Herschel Wedge + Baader CaK for Calcium K line

Camera: DMK 31AF03

1407 (GMT+8):-


1408 (GMT+8):-


1418 (GMT+8):-

20080913 Moon

It's just a day before the Chinese Mid-autumn festival (aka Mooncake festival), so I took my Tele Vue Ranger out for some test shots. My Ranger was not used for quite long.

I've also tested to see if I can use a Kenko 2x Teleplus with a telescope, but sad to say, it cannot because the camera will complain about a bad lens connection and result in an error.

Finally, I have added a Tele Vue 2x together with an extension tube to take another shot at higher power. Two frames were stitched together to form the final image. At ISO 100, exposure was at 1/8s and there's no tracking, so I've to reduce the size of the image to around 50% of the original.

Canon 450D was used.

2300 (GMT+8), Canon 450D with Tele Vue Ranger at prime focus, curve adjusted and cropped, no unsharp masking or any other processing:-


2306 (GMT+8), a Tele Vue 2x barlows was added, together with an extension tube to reach focus, 50% resized:-

20080913 Sun

It's nothing special today, but when I arrived home, the sun was so low in the sky that it's virtually meaningless to shot. So in order to save time, I didn't use my H-alpha setup, but instead, I used my Canon 450D with my 200mm f2.8L and a Kenko 2x for shooting.

1737 (GMT+8), with thousand oaks type 2+, I've to use ISO 1600 in order to hand held this setup:-


1738 (GMT+8), without the solar filter, I've to use ISO 100 plus f/64 and still got overexposure, never look into the view finder for this kind of shot, and make sure the sun is low enough in the sky with dense cloud/pollutant:-


Just a record.

More new products from Lunt's

As far as I heard from their yahoogroups, we will have:

1. 50mm Sodium (!!) filter: notice that it would not be a regular product, so you will need to contact them if you're interested.

2. 75mm filter set: we were told it's coming soon, I really wish to see how the obstruction will look like, and how does it perform

3. 35mm front etalon scope: this should be interesting for those who wanted to take fast full disc shot, it has only around ~200mm focal length which should be great for this purpose

With the recent price reduction from Coronado, I believe the narrow band solar instrument market should be very interesting in the coming few months.

Introducing my friend's astronomy blog

I'm very happy to know that one of my very close observing buddies has started his own blog, you can see it here:

http://astropaul.blogspot.com/

Since it's just started, there is not much thing there yet. To read more of his work, you can also visit his website:

Celestial Fantasy by Paul Ng

but I guess he won't update it as often as his blog afterward, since a blog is far easier to maintain.

Telescope/Lens for the next total solar eclipse

My Canon 200mm f2.8L was used with a Kenko 2x Teleplus, but as you can see from below:



the internal reflection is very bad. Another friend of mine was using another lens, and also another Kenko 2x Teleplus, and he got very similar internal reflection pattern as well. Therefore, I should not use this Kenko 2x for the next time.

My TG-SP II should probably limit me to stay around 400mm and I should not go anything much heavier. So right now I've three candidates in my mind:-

1. Canon 400mm f5.6L:- this is a proven lens, both for total solar eclipse, the diamond ring, as well as for deep sky imaging. However, my TG-SP II will not be able to support it for deep sky imaging, and thus, this lens will be less than useful for me.

2. Canon 100-400mm f4.5-f5.6L:- this is also a proven lens, but I've to ask my friend to see if it has any internal reflection for the diamond ring. It's a little bit heavier than the Canon 400mm f5.6L so the TG-SP II should still be able to carry it for short exposure like up to a few seconds. Deep sky imaging is not a real concern for me, again due to the TG-SP II and thus I don't have to worry about it's deep sky performance. It features a wide zoom range as well as the image stabilizing function and thus, it should be very versatile for day time imaging.

3. Borg 77ED II:- this is a very light weight telescope, between the weight of the above two lenses. It has 500mm focal length which is even more attractive for solar eclipse. Internal reflection is an unknown and I've to do some Google work to see if that's okay on this aspect. Deep sky imaging is out of question due to the TG-SP II again. What makes it attractive again is due to its versatility - it's a telescope so that it can be used for visual observation, however, this is too close to my existing Tele Vue Ranger. But then it will be a perfect match with a Lunt's Solar System 75mm H-alpha filter, if I ever go for one.

In conclusion, if the totality alone is concerned, (1) will be the best. If day time photography together with totality is concerned, (2) will be the best. If other than totality, visual observation and H-alpha possibilities are concerned, (3) will be the best.

To me, right now the Borg 77ED II is the lowest priority candidate, since I would want something bigger than my Tele Vue Ranger, let say the Borg 101ED. Of course, the 101ED will be too long, in terms of focal length, for the totality given my TG-SP II. So most likely I will go for a Canon 100-400mm f4.5-5.6L IS due the versatility.

--
Follow-up

From this shot:-

http://www.flickr.com/photos/ejwwest/2723325371/meta/

Canon 100-400mm f4.5-f5.6L does not even show internal reflection with a Canon 1.4x.

And this shot:-

http://www.lichtjahre.eu/lj_gallery_diamantring_as.html

also shows zero internal reflection, this is the Canon 100-400mm f4.5-f5.6L without any tele-converter.

20080907 Sun

Seeing not *very* bad at 3/10, trasparency very low at 2/10 at best, could be worse. Sun remained inactive, but we have a couple of medium sized prominences if you looked carefully.

First few are taken with a Borg 45ED II, Coronado Solarmax 40 with BF10, DMK 31AF03 firewire monochrome camera.

1542 (GMT+8), on pushing, you can see a prominence:-


1544 (GMT+8), pushing the exposure, an even dimmer one can be found on the other quadrant:-


1548 (GMT+8), a Tele Vue 2x is used to push the image scale:-


And then I switched to my C5/PST setup, but due to the wider bandwidth, the resolution increase cannot offset the loss in contrast due to the poor sky:-

1556 (GMT+8):-


1559 (GMT+8), target for surface detail, even worse:-


Despite the poor sky, the session today told me that my C5/PST based setup can be used again indoor due to the change of the position of the sun from inside my home. A good thing indeed.

Total Solar Eclipse Trip 2009

This will be a very long eclipse, you will have more than 5 minutes of totality in most places. The good news is that, the eclipse path will cover many bigger cities and so you have a lot of convenience choices. The bad news is that, there is not a place where the average cloud cover would be low enough and the air pollution of those bigger cities is going to be a real problem.

Therefore, we should place sight seeing as the first priority and the totality will be dessert, or an added bonus.

So far I believe that I will take my whole family with me, if that's possible. And at the same time, I believe that I will join those tours offered by traveling agency so that it will be more well organized and we will be better served.

Of course, since we still have nearly 10 more months to plan, I'll leave all options open.