Friday, November 30, 2007

Early morning indoor viewing

Just woke up to cover the kids again, it's pretty cold these days. That's around 4:00am, the mighty hunter Orion is hanging outside. Took my Canon 10x30 IS out to have a quick look.

Very nice view, M42 shows a distinguish fan shape, the transparency is so good in terms of Hong Kong sky.

Next, I turned to Sirius, this bright star is very attractive in a small bino, very bright and better than any diamond on earth, maybe that's why it's hanging in the sky so that everyone can see it for free.

I tried to scan for M41 but failed. Then I put on my eye glasses, and let myself know where it should be, then I pointed my 10x30 there, after 1 or 2 seconds, it's right there! Stars are resolved partially, which is a great view. Believe it or not, a fully resolved cluster is not as nice as viewing a partially resolved cluster. That's because it gives a dynamic sense, some stars popped in and popped out randomly if it's partially resolved. A very nice view.

So, I ended my 2-3 minutes of viewing and headed back to sleep.

Again, the IS button is magical! Without pressing the IS button, I can never be sure if I have seen M41 or not, IS didn't only let me detect it, but to let me see it partially resolved! So nice!

Thursday, November 29, 2007

Guiding exercise

Took my TG-SP II out, set it up by the window, put my Borg 45ED II there, insert the 9mm Meade reticle, given the good sky these days, I could easily see three stars in the same field randomly. Balancing the Borg 45ED II requires only the bundled counter weight at nearly the front end, that means if I'm to guide using the Borg with a C mount lens, this counter weight will be enough. Very portable!

I centered the adjustable cross hair of the reticle eyepiece in a star, feels like video game! Then I pressed the red button, i.e. to stop the RA drive, the star drift very nicely. I rotated the eyepiece to align the cross hair with the RA axis. Then I press the blue button to set the RA drive at 2x, soon the star went back to the center. With this simple stop and 2x mechanism, no backlash will be seen, since the drive is always running in a single direction. Simple and elegant.

Then I left the setup for a while, let the star drift.

The mount is not polar aligned basically, I just polar aligned very roughly by pointing it to the magnetic north. :-)

After a few minutes, I finally detect drift. I carefully turn the DEC knob and soon it's back to the place. Turning the knob does not induce much vibration, not really detectable to the view in the eyepiece. A good sign.

Seems like it's a very reasonable setup to do some simple imaging. I always want to do short exposure like within 2-3 minutes with 200mm at most, so I think that's enough.

Wednesday, November 28, 2007

A high transparency night

Tonight the transparency is pretty high, I would rate it a solid 8/10, but of course, it's just by the standard of Hong Kong. If I took into account of the great sky from other part of the world, it would become a very poor 4-5/10 at most.

I could see no more than 20 stars with naked eyes, that's it. The sky is still showing a dirty bown hue...

However, it's already great in our standard. I didn't take any images tonight, since there's no good object from inside my home. Also, why it's so transparent is due to the wind.

Anyway, worth to write down, just as a record.

Studying ghost craters?

After reading the S&T article in Dec 2007, I wonder if the study of ghost crater is a worthy project.

First of all, as for fun, it's nice to have a collection of ghost crater images, rather than just taking mug shots of famous craters again and again.

Secondly, I wonder if the distribution of these ghost craters have some "scientific value". Suppose ghost crater is created by lava flow (reasonable, right?), and given the moon is always facing us at around the same face (*), when lava flows, it should have similar tidal effect like that of the earth, i.e. the lava will be thicker at the side near the Earth.

Suppose craters are formed randomly, given the thicker lava layer at the side near the Earth, we will see less ghost craters if the lava is thick enough to cover old post-mare craters, or we will see more ghost cracters if the lava is not thick enough. When I say more, or less, I mean when compare to the limb of the moon as seen from the Earth.

So, given the lava is really thick enough in the middle, we should see nearly no ghost crater there. In that case, ghost craters will be found nearly solely nearer to the limb?

And given the lava is not thick enough even in the middle, we should see ghost crater in the middle but less nearer to the limb, since it's even thinner there.

(*) But if we found it pretty close in number, does that mean the age in which lava flows is older than the time when same face of the moon is locked to the Earth?

Sunday, November 25, 2007

Cloudy day exercise

What to do during cloudy day? Here're two shots of the cloud, one in IR and one in white light (including IR signal), narrower bandwidth is always sharper, I guess it's due to the fact that it's less demanding on the optics, and it's also less affected by seeing:-

1654 (GMT+8), IR:-

1655 (GMT+8), white light:-

A bird taken with a Cosmicar 150mm f/3.2:-

Saturday, November 24, 2007

20071124 Sun

We got no big prominence, no big active region, but we do have some small QRF, some small nice surface feature, plus a few nice prominences. Seeing 2-3/10, transpareny like 6/10. SM40/BF10/Borg 45ED II, one shot double stacked with PST etalon.

1224 (GMT+8), SM40/BF10/Borg 45 ED II, DMK 31AF03, try to see those QRFs, they're pretty hard to find in this shot:-

1226 (GMT+8), same setup as above, prominence only:-

1229 (GMT+8), same setup, but with PST etalon to make it around 0.6A, notice that those QRFs are far easier to see now:-

Same as the last shot, but this one is b/w to maximize the contrast:-

The small difference in bandwidth really helps here.

The small new active region in the middle is 975 as found out later.

Tuesday, November 20, 2007

20071120 Lunar Observation

C5 with Tele Vue 2x Barlows, DMK 31AF03. Seeing 2-5/10, transparency 6-7/10.

Before taking the images below, I used my binoviewer with 20mm eyepiece to look around to see if there's anything interesting to my eyes.

2322 (GMT+8), Copernicus and on its left, we got Reinhold and Reinhold B (smaller), and on the right, we have Gay-Lussac. Copernicus is my prime target of this shot, I intend to capture the central peaks. "There is something wrong with the impact-melt idea when applied to Copernicus" for there is a significant different from the theoretical model and the measured value on the floor to the highest peak. [The Modern Moon - A Personal View - Charles A. Wood]

2326 (GMT+8), on the far side we have Anaxagorus, [The Modern Moon] said its floor is virtually invisible, and sometimes the bright top of its central peaks can be seen from Earth, shall try again later:-

2328 (GMT+8), Gassendi but this is not my prime target in this shot, the very shallow crater-like circular feature catches my attention, actually, this is the feature which attracted me to start this short imaging session, I'll look for information about it:-

Additional remarks after posting on Cloudynights, we have some nice information here:-

Lunar Observing forum

Carol L from Cloudynights added labels for me:-

And I just read an article from Dec 2007 S&T, I guess it's one of those ghost craters, or pre-mare crater. I'm wondering if I should start a fun project to hunt for more ghost craters.

Saturday, November 17, 2007

20071117 Sun (prominence and AR974)

Seeing was 2-5/10, transparency 6/10, two big prominence, one small active region. Borg 45ED II, SM40/BF10 used for low power shots, C5/PST used for high power shots.

Surface detail at 1247 (GMT+8) and prominence at 1249 (GMT+8):-

Close up of AR974, detail shown in the photo below:-

Prominence close up at 1316 (GMT+8):-

Prominence close up at 1318 (GMT+8), this one is dimmer than the above one:-

Finally, a poor attempt to capture closer up (2x as above, i.e. ~2500mm) of 974, seeing obviously couldn't support:-


I joined two projects:-


Actually, I started with SETI@home alone at first, but after so many number crunching, it's hard to find any result. Of course, it's expected, but anyway, to use resources in a better way, I joined Einstein@home which should be more promising.

No matter how, I hope this little effort can help a bit in those research afterall.

However, the bottom line is that, I believe these projects are sucking a lot of electricity and "contributed" quite a part in the pollution problem. So, let's just keep it at certain level only.

Friday, November 16, 2007

Finally 100% sure about Comet Holmes

All the previous observation was uncertain, due to the serious light pollution and the poor sky condition.

Today, I went to a slightly darker place which was a larger football field with no spot light. No constellation could be recognized basically, so it's not really a good place. I arrived there at around 10:10pm, and was very puzzled about where to look. The football field was closed for mantainence, so all I could do is to stay outside and try to look up, there were quite a lot of trees around. It's not a problem if I could go inside, but then I couldn't, and therefore the view was highly blocked. There were some street lights around, too.

When I were about to give up at around 10:30pm, I told myself, why not scan around with my bino? So, I first pointed my Canon 10x30 IS to a bright yellow star, Taurus
it should be. The distinctive star field pattern there could not be mistaken. Then I tried to scan around to find M45, ok, no problem. So, I know where and then... I thought I knew which was Capella, pointed there, confirmed. Feeling confident, I scanned to Mirphak, found. Then a big fuzzy patch of light nearby...

I double checked, cup my hands around the eyepiece, no, it's not internal reflection. Took away my eyes, put back, no, it's not fog or moisture from my eyes.

Yes, it's the comet!!!

Hey, it's big!!! Very big! Even in this light polluted place!

I then setup my C5, it's funny to setup a telescope in the street, but that's ok. With my Pentax 40mm XL, the comet was not very apparent, I would say it's not as good as in the Canon 10x30 IS, I love more sky context, the constrast was not as good as well. The 20mm Japanese Widescan III was no good in this case, I could see the reflection of my eye ball under light pollution, this was not an eyepiece under light pollution. The 13mm Nagler gave the best view, but again, it lacked of context due to the smaller field of view.

I love the view from my Canon 10x30 IS most.

In short, it feels like a brighter M31, it's more spherical, and it's even bigger under light polluted sky. I love this view!

Thank God, I eventually got a good view of it!!!

Wednesday, November 14, 2007

Wow! That's the feeling!

I tried my Canon 10x30 IS on the moon again just a few minutes ago. With the earthshine, it gives a truely 3D impression, you saw a huge ball hanging in the sky, with two more bright stars around (1831 GMT+8). Wow! That's the feeling that makes astronomy so attractive!

Chromatic abberation is minimal, it's there if you look for them, and it's like a very thin line of purple and green on the lunar disc, just a very little bit. Craters are well seen with very high constrast.

Finally, a simple shot acquired by a Cosmicar 150mm f/3.8 with 1.5x tele-extender, DMK 31AF03, it's on the soft side, but anyway, it's more for deep sky objects than for high resolution work, field flatness is the prime concern there:-

Nexstar Mount Parts

The Nexstar mount repairing attempt failed, so I removed some parts inside, hope that someone will find them useful:

The PCB, it's not functioning properly, I tried to fix it but failed, maybe some chips are still working?

The motors, they works perfectly, since the ALT circuit of the above PCB still works, I know the ALT motor works. Then I swap the ALT circuit to control the AZ motor, and it works, too. So, I know both motors work perfectly. They're very nice Pittman motor with encoder.

ALT and AZ gears, telfon washer, bearing, etc:-

The hand controller:-

Finally, this is the chip which I tried to replace for repairing, but after replacement, the issue persists. The chip is ordered from Mouser, I soldered one on the above PCB, one is left unused:-

20071114 Catch some sunshine

Transparency 7/10, seeing 2-3/10, sun activity low.

First of all, two shots to compare the effect on the Tmax, both acquired by SM40/BF10/Borg 45ED II at prime focus:-

1509 (GMT+8), optimized for the QRF near the bottom:-

1512 (GMT+8), optimized for even illumination:-

Notice that some surface contrast is compromised if we opt for even illumination.

A prominence only shot at 1513 (GMT+8):-

Double stacked with PST etalon, 1518 (GMT+8), seems like it's the best of both world, you got a prominence extended all the way into the solar disc as a QRF, illumination is quite even, too:-

The b/w version shows better how the prominence and the QRF are indeed one, it's also orientated like the first two:-

Finally, I did a shot soon after sunset, it shows the color of the sky, the moon and Jupiter, plus an aeroplane trail, click for full size:-

Monday, November 12, 2007

Early morning indoor scanning

Saw Orion hanging outside my home window at around 5:00am this morning, so I took my Canon 10x30 to have a look, and I found Tarus down under the mist, only the orange bull eye star could be seen...

I was thinking if I could get a look at Holmes again?

So, I tried to guess where was M45, found it from the corner of a shorter building near by, if I was late by 15 minutes, I'm sure that I would miss it. Looked around, found Mars hanging high in the sky, it was pretty bright.

Holmes was not in the view obviously, so went back to sleep.

Sunday, November 11, 2007

20071111 A new active region

Prominence activity is lower today, but we got a nice QRF and another tiny active region, not bad already for solar minimum. Seeing is 3/10, transparency like 2-3/10, pale blue sky, typical these days.

1342 (GMT+8), Borg 45ED II at prime focus:-

1343 (GMT+8), Borg 45ED II at prime focus:-

1346-1350 (GMT+8), Borg 45ED II at 2x, a mosaic of 2x3, seeing very poor, ugly result:-

1354 (GMT+8) Borg 45ED II with 3x barlows:-

Cloudy night exercise

It was cloudy, with nothing else to do, I dig out my binoculars to compare, with remote terrestial targets. My Pentax 10x50 PCF III is good, I love the view, it's contrasty and bright. Then, I used my Canon 10x30 IS, to my surprise, the view seems brighter despite the far smaller exit pupil. And the view is even more contrasty, it's wider too. Some remote detail which is not apparently in my Pentax, is eye catching in my Canon. I didn't use the IS button, since I wanted to compare the optical quality. I believe the bigger exit pupil of the Pentax will show up when used in darker location with deep sky objects.

Next, I took out my C5, trying to align the Rigel Quick Finder, I didn't do it after all these years, since I'm only doing imaging on brighter targets, finder is simply not needed. However, I'll want to try Holmes with it soon, so the alignment is part of the preparation, see if I can have chance tonight.

Saturday, November 10, 2007

20071110 Prominence day!

Seeing was 2/10, couldn't support high image scale indeed, transparency also low at 2/10, so it's pushing the equipments indeed. We don't have much surface activity, but the prominences are great.

First is a full disc mosaic to show where those prominences are, two frames stitched together, 1334 and 1335 (GMT+8), Ranger at prime focus:

1338 (GMT+8), Ranger 2x, SM40/BF10:-

1340 (GMT+8), Ranger 2x, SM40/BF10:-

1341 (GMT+8), Ranger/SM40/BF10 at 2x:-

1342 (GMT+8), Ranger 2x:-

1354 (GMT+8), C5/PST at prime focus:-

1353 (GMT+8), C5/PST at prime focus:-

A raw video encoded to MPG, taken by C5/PST with 2x barlows, too noisy and seeing too bad to be processed:-

Thursday, November 08, 2007

Taurids on 5th of Nov?

I've setup my DBK 21AF04 with a 2.3mm c mount lens to capture through the whole night from something like 23:xx local time to the next morning, each frame was at 18s exposure at f/1.2, unluckily, I've to shoot through window glass and my focus was pretty poor, after scanning for the whole 13 minutes worth of video at 30fps, I found one suspect only:-

Orion is underlined, the suspect is at the yellow arrow, the orange arrow is Sirius. And the next frame for comparison:-

Just an record, and it can never be sure.

Sunday, November 04, 2007

Comet 17P/Holmes again

It's supposed to be very big, like half the moon.

I just back from the "street", it's very similar to the view I saw last Friday from the same location, maybe the poor transparency (something like 2-3/10, Capella invisible to naked eyes) and maybe the light pollution. It's definitely non-stellar in my 10x binoculars, but it big size cannot be detected, just like that view of the last week. Yellowish but still tiny disc?

Fixing the Nexstar mount again

This Nexstar mount is left untouched after an accident four or five years ago. The hand controller was suspected to be faulty and sent back for repairing but it's lost eventually. Until a few months ago, I managed to buy a replacement from astromart, but the problem persisted, so I concluded that it's not the controller but something in the main circuit board inside the mount body.

The symptom is, the ALT motor will slew in both directions without problem, but the AZ motor will only slew one direction but not the other one. I swap the controlling circuit by swapping the plugs and the problem migrated to another motor. I can also reverse the polarity of the driving circuit of the same motor to enable the mount to slew in another direction.

I carefully trace the circuit board this time, and I found the driving circuit (orange), the decoding circuit (blue, to read the signal from the encoders of the motors), and I also found that each functions are controller by two sets of four identical chips.

So far after some examinations, I concluded that a certain chip is faulty and I circled it in purple. I shall see if I can order replacement chip.

20071104 Silent Sun

The sun is very silent today, there's a rather big prominence on one side, but it's too dim to be captured at larger image scale. My C5 based f/10 setup cannot detect it even at 1/30s and high gain. Only my Borg 45ED II at f/8 (stopped down to 40mm) can detect it at 1/30s and high gain. There's a nice QRF however. Seeing is like 3/10, transparency at 6/10.

1550 (GMT+8), SM40/BF10/Borg 45ED II:-

1551 (GMT+8), SM40/BF10/Borg 45ED II:-

I've taken today as a chance to fine tune my PST etalon, now the internal reflection issue is reduced, still here, but it's not very annoying already. Silent sun gives this chance. :-)

A random patch taken at 1546, C5/PST:-

Saturday, November 03, 2007

C5 PST with Cheapy-ERF setup

This is that setup in action.

A picture worths a thousand words here.

Friday, November 02, 2007

Power for TIS DMK, DBK or DFK

DMK camera uses standard 6-pin 1394 power to connect to the computer, these type of cable will also carry 12V DC for the DMK. However, some notebook PC, despite having 6-pin ports, might not deliver power if they're in battery mode. Therefore, you will need something else to provide power for the DMK.

Normally desktop PC, or laptop PC in A/C power mode, will provide power through a 6-pin 1394 port, in that case, you don't need a seperate power source.

Another case is those notebook PC with only 4-pin 1394, this kind of port also will not provide power.

I found a 1394 hubs with power input is the best solution. The above 1394 hubs is acquired from ebay, it's inexpensive, light weight and compact. It has a small 12V DC in plug, with center positive just like most devices do.

The battery box can be found in many electronic shops, they carry 8 AA batteries. And the output terminal is those "9V" style connector as show above.

Since DMK cameras are rated at 8-30V DC, we can provide anything from 8-30V to the 1394 hubs, but to play safe, we should better stay around 12V DC which is the normimal value for 1394 standard. For the 8 AA battery box, it gives us two possible options:-

1. 8 AA standard akaline battery: 8 * 1.5V = 12V
2. 8 AA rechargeable battery: 8 * 1.2V = 9.6V

I have tried both options and they both work without problem. I even tried to power two cameras at once, one DMK 31AF03.AS and another one DBK 21AF04.AS, they work flawlessly.

Suppose I use 8 AA 2300mmAh rechargeable, the batter box can provide power for virtually a whole night of operation for a single camera. I've connected the battery box to the 1394 hubs with a simple DIY cable, but I believe such a cable can be acquired off the shelf easily.

A powered hubs has an advantage to let you connect two cameras, or even more to the same PC. IC Capture supports multiple cameras, but be sure to consider 1394 bandwidth capacity, for example, my DMK31AF03.AS when running at full 1024*768*30 fps, it will take up all bandwidth virtually so that you probably cannot use another device at the same time.

Apart from the above solution, you may also buy a 1394 Y-cable with power input from TIS, I didn't try it but I think it's simplest.

Finally, I have even tried to use a third option, it's to connect the 1394 hubs to a powered 1394 connection to get power from that connection. For example, my notebook PC has a 4-pin port which does not provide power, and so I also connect my desktop PC to the same hubs with a 6-pin to 6-pin cable, and then I connect my DMK to the same hubs, and everyone got power! Another bonus of this setup is that, you got 1394 networking between your desktop PC and your notebook PC.