2009-12-29
Bah
Cloudy weather in Oita, where I will be spending New Year.
I was hoping to try out my Tak FCT-125 for the first time - I bought it in Japan, unseen, and had it delivered to my in-laws. Oh well, at least I can bring it home. Shiny shiny.
The cold weather will be a nice change from Singapore and I'll enjoy the trip to Kyushu.
I had to shrink the image to stop WordPress screwing up the aspect ratio. WordPress appears to be buggy as all hell.
I was hoping to try out my Tak FCT-125 for the first time - I bought it in Japan, unseen, and had it delivered to my in-laws. Oh well, at least I can bring it home. Shiny shiny.
The cold weather will be a nice change from Singapore and I'll enjoy the trip to Kyushu.
I had to shrink the image to stop WordPress screwing up the aspect ratio. WordPress appears to be buggy as all hell.
2009-12-13
Still b0rked
The Big-endian specific date bug in php is still not fixed in Ubuntu, and I can't be bothered compiling php from source, so the dates are still wrong.
Meanwhile, in the irrational desire department, we have the Norhtec Gecko Keyboard!
http://www.reghardware.co.uk/2009/12/18/norhtec_keyboard_pc/
http://www.geeky-gadgets.com/norhtec-gecko-surfboard-keyboard-pc-18-12-009/
Not as good a spec as the Eee keyboard, maybe not as cool as the TouchBook, but I love the retro look and it would make a decent little server at the low price of USD99.
Meanwhile, in the irrational desire department, we have the Norhtec Gecko Keyboard!
http://www.reghardware.co.uk/2009/12/18/norhtec_keyboard_pc/
http://www.geeky-gadgets.com/norhtec-gecko-surfboard-keyboard-pc-18-12-009/
Not as good a spec as the Eee keyboard, maybe not as cool as the TouchBook, but I love the retro look and it would make a decent little server at the low price of USD99.
2009-11-20
b0rked
b0rk b0rk b0rk is b0rked due to b0rkage in php. All years are showing as "0000", and all new posts are being created in year "0000". I'll just wait for the updated php package rather than recompile from scratch.
2009-11-16
Nothing doing
Clouds, rain, thunder and more clouds. Not much going on recently.
I bought 72mm and 82mm IDAS LPS-P2 filters to use with camera lenses. On the modified 5D, unlike cropped-frame cameras, there is no room to put an "FF" filter behind the lens and in front of the mirror box. So, I will use these filters on the front of lenses. They can also be used with my E-620, and in 'scopes that can cover a medium format frame.
After trying to buy Kenko R64 filters, which apparently have been discontinued, I bought various B+W 091 MRC filters from B&H. Stacking an 091 filter with an LPS-P2 results in a very wide (30-40nm) H-alpha filter.
In the testing pipeline is:
Scopes:
Lenses:
In the "hack write-up" pipeline:
I bought 72mm and 82mm IDAS LPS-P2 filters to use with camera lenses. On the modified 5D, unlike cropped-frame cameras, there is no room to put an "FF" filter behind the lens and in front of the mirror box. So, I will use these filters on the front of lenses. They can also be used with my E-620, and in 'scopes that can cover a medium format frame.
After trying to buy Kenko R64 filters, which apparently have been discontinued, I bought various B+W 091 MRC filters from B&H. Stacking an 091 filter with an LPS-P2 results in a very wide (30-40nm) H-alpha filter.
In the testing pipeline is:
Scopes:
- Pentax 125SDP vs TOA130F w/35 flattener
- Pentax 125SDP with 67 reducer vs TOA130F with 35 reducer
- Borg 125SD 67 reducer vs 35 reducer
- Borg 125SD with 67 flattener
- Tak FCT-125
- Pentax 75-SDHF vs Sky-90 vs FSQ-85ED vs Borg 77EDII (and perhaps WO M80FDII)
- ETX-90 vs Q-3.5
Lenses:
- Pentax 645 300/4 ED IF
- Olympus OM 300/4.5
- Olympus OM 350/2.8
- Olympus OM 250/2
- Canon FD S.S.C Fluorite 300/2.8
- Sigma 400/5.6 APO
- Olympus ZD 150/2
- Nikon 180/2.8 ED
- OM 50/1.8 vs OM 50/1.4 vs OM 50/1.2 vs Pentax 55/1.8
- OM 24/2.8 vs OM 28/2.8
- CZJ 135/3.5
In the "hack write-up" pipeline:
- Vixen SXW Dec adjustment
- QHY8 fix follow-up
2009-10-30
EM-200 PSU
For some reason, I had gotten it into my head that the EM-200 required 4 Amps at 24 Volts, probably because this is what the Tak PSU provides. But checking the Takahashi website, you can see the specs for the various EM-200 mounts.
The Temma2-Jr, which I have, only requires 0.3 to 2.0 Amps.
So, a 24V, 48W power supply is sufficient. I bought a cheap Apple Powerbook G4 replacement PSU (24V, 65W) from eBay, and hacked up a cable using a spare connector hacked off another old PSU, extended it with some spare mains wire.
It doesn't look pretty, but it works fine.
The connectors have been taped up since the photo.
I noticed something that seemed strange to me when checking the output of the PSU on my oscilloscope. There was a roughly 1Hz, 1V amplitude triangular signal on top of the base 24V. Yes, 1Hz. I would've expected 50Hz or some harmonic from the mains. I tried various time bases to make sure it wasn't an aliased signal. Nope, definitley around 1Hz.
I'm assuming the EM-200 has a regulator as it can be run off batteries with quite a wide voltage range - I measured about 27V for the two 12V batteries wired in serial that I used before. I don't think this will cause any damage, and even if the variation in voltage gets to the motors, the feedback control from the encoders should deal with it.
Initial tests seem fine. The mount slews and tracks as per normal. The motors do seem to have a regular slight variation in sound when slewing, but I'm not sure if this is any different from running on batteries.
We'll see how it goes long term. I expect it will be fine.
The Temma2-Jr, which I have, only requires 0.3 to 2.0 Amps.
So, a 24V, 48W power supply is sufficient. I bought a cheap Apple Powerbook G4 replacement PSU (24V, 65W) from eBay, and hacked up a cable using a spare connector hacked off another old PSU, extended it with some spare mains wire.
It doesn't look pretty, but it works fine.
The connectors have been taped up since the photo.
I noticed something that seemed strange to me when checking the output of the PSU on my oscilloscope. There was a roughly 1Hz, 1V amplitude triangular signal on top of the base 24V. Yes, 1Hz. I would've expected 50Hz or some harmonic from the mains. I tried various time bases to make sure it wasn't an aliased signal. Nope, definitley around 1Hz.
I'm assuming the EM-200 has a regulator as it can be run off batteries with quite a wide voltage range - I measured about 27V for the two 12V batteries wired in serial that I used before. I don't think this will cause any damage, and even if the variation in voltage gets to the motors, the feedback control from the encoders should deal with it.
Initial tests seem fine. The mount slews and tracks as per normal. The motors do seem to have a regular slight variation in sound when slewing, but I'm not sure if this is any different from running on batteries.
We'll see how it goes long term. I expect it will be fine.
2009-10-29
First light with QHY8
Conditions have been terrible of late, but finally the skies cleared and I was able to try out my new QHY8 on October 18th.
I used Borg parts to attach it to a EOS body mount (more on this in another post) and an OM->EOS adapter to mount it on the back of my OM 350/2.8. The Borg parts allow mounting filters inside. I stacked a Kenko R64 and Baader Fringe Killer to make a fairly wide-band H-α filter.
The results were not good to say the least.
The OM 350/2.8 hadn't shown any problems in daytime and night-time scene test shots, nor in fixed-tripod shots of star fields. This looked like the CCD was very badly misaligned with respect to the image plane.
Without any measurements, it was clear enough that the CCD was not square with the front plate.
Measuring confirmed this:
A 3mm difference from edge to edge is pretty huge.
So, I set about taking the QHY8 apart.
The QHY8 is quite simple and easy to take apart. Remove the four screws holding on the fan. In the resulting holes there are a further four small hex screws. Remove these and you can open the case.
Note that opening the case will break the silicone sealing around the USB and power ports. This is no real problem as these can be re-sealed. The QHY8 doesn't appear to be fully air-tight anyway.
Besides, before attaching the Borg parts, I had already taken off the original T-ring threaded attachment with AR glass, that protects the CCD, exposing the innards to the air. On the first run, it fogged up quickly, taking over 40 minutes to clear. Leaving it in my dry cabinet over a couple of days solved this minor problem. It now clears after a couple of minutes. Presumably the foam had been saturated when in storage/transport.
In the above photo, you can see the "cold finger" that the CCD is attached to. I didn't pry this up, but presumably it is attached to the Peltier coolers and it seems to be insulated from the main board. On the metal plate, there are three holes, but only two plastic spring-loaded bolts/spacers, which are not threaded, on the right hand side. The top of the bolts merely rest against some foam on the inside of the front plate.
This hardly seems like a mechanism designed to obtain and keep accurate alignment of the CCD. Photos of other QHY8 units on the web show a quite different board with three metal screws providing a reasonable-looking mechanism to adjust the CCD alignment.
Furthermore, these plastic spacers/bolts actually rest on top of components on the board.
It's difficult to see from this photo, but the front bolt has been bent and has left some marks on the chip it rests on top of. Not great.
As well as some questionable design, the assembly isn't great either. The power cables for the fan were not correctly placed in their channel, which has led to some fraying.
Anyway, I had a look through my little collection of bolts and bits and pieces and found a replacement plastic screw for a Borg helical focusser that fit the hole. This presses up against the foam on the underside of the front case, but didn't help with alignment until I added shims made from some spongy double-sided tape. I simply kept adding shims and measuring the depth of the CCD at its corners until it was fairly level and did some fine-tuning using the torque on the hex bolts holding the front and rear casings together.
I got the CCD as square to the front surface as my super accurate cheapo plastic vernier gauge could measure - which should be around 0.05mm.
At first I was pretty angry with the poor design and construction. This is a relatively inexpensive CCD, but still, the design, construction and QC is clearly very poor.
But at least it was easy to fix. The fix is temporary, and I intend to get a suitable plastic spacer and spring for a more permanent fix. But if this kludgy fix holds for long enough, I expect it will remain until the CCD gets out of alignment enough to annoy me.
One good thing about the QHY8 is the rubber seal between the front and rear casings. This seems to do a good job of damping the vibrations from the fan.
For not much more cash than a modified DSLR, you get a compact, lightweight, cooled OSC camera with 16-bit output and a decent-sized CCD. Issues with the drivers seem to have been worked out, and I had no problems using the QHY8 with Nebulosity on my Mac. A new DSLR would have higher resolution, but that's not much of a benefit for astro imaging.
However, with the QHY8, at least the one I got, you do have to put up with dodgy design, cheap construction and poor quality control. If you don't like pulling things apart to fix them and don't have a local dealer to sort stuff out for you, I wouldn't recommend the QHY8. The Orion Starshoot Pro, settling for a smaller CCD, saving and holding out for a good deal on a used SBIG camera might be better options.
Now, I just need some clear skies to test the kludgy fix.
I used Borg parts to attach it to a EOS body mount (more on this in another post) and an OM->EOS adapter to mount it on the back of my OM 350/2.8. The Borg parts allow mounting filters inside. I stacked a Kenko R64 and Baader Fringe Killer to make a fairly wide-band H-α filter.
The results were not good to say the least.
 |
| 100% crop from top left |
 |
| 100% crop from top right |
 |
| Full frame |
The OM 350/2.8 hadn't shown any problems in daytime and night-time scene test shots, nor in fixed-tripod shots of star fields. This looked like the CCD was very badly misaligned with respect to the image plane.
Without any measurements, it was clear enough that the CCD was not square with the front plate.
Measuring confirmed this:
 |
| 11mm on the top left |
 |
| 8mm on the top right! |
A 3mm difference from edge to edge is pretty huge.
So, I set about taking the QHY8 apart.
The QHY8 is quite simple and easy to take apart. Remove the four screws holding on the fan. In the resulting holes there are a further four small hex screws. Remove these and you can open the case.
Note that opening the case will break the silicone sealing around the USB and power ports. This is no real problem as these can be re-sealed. The QHY8 doesn't appear to be fully air-tight anyway.
Besides, before attaching the Borg parts, I had already taken off the original T-ring threaded attachment with AR glass, that protects the CCD, exposing the innards to the air. On the first run, it fogged up quickly, taking over 40 minutes to clear. Leaving it in my dry cabinet over a couple of days solved this minor problem. It now clears after a couple of minutes. Presumably the foam had been saturated when in storage/transport.
In the above photo, you can see the "cold finger" that the CCD is attached to. I didn't pry this up, but presumably it is attached to the Peltier coolers and it seems to be insulated from the main board. On the metal plate, there are three holes, but only two plastic spring-loaded bolts/spacers, which are not threaded, on the right hand side. The top of the bolts merely rest against some foam on the inside of the front plate.
This hardly seems like a mechanism designed to obtain and keep accurate alignment of the CCD. Photos of other QHY8 units on the web show a quite different board with three metal screws providing a reasonable-looking mechanism to adjust the CCD alignment.
Furthermore, these plastic spacers/bolts actually rest on top of components on the board.
 |
| Plastic bolt sitting on top of components |
It's difficult to see from this photo, but the front bolt has been bent and has left some marks on the chip it rests on top of. Not great.
 |
| Fraying of fan power cables |
As well as some questionable design, the assembly isn't great either. The power cables for the fan were not correctly placed in their channel, which has led to some fraying.
Anyway, I had a look through my little collection of bolts and bits and pieces and found a replacement plastic screw for a Borg helical focusser that fit the hole. This presses up against the foam on the underside of the front case, but didn't help with alignment until I added shims made from some spongy double-sided tape. I simply kept adding shims and measuring the depth of the CCD at its corners until it was fairly level and did some fine-tuning using the torque on the hex bolts holding the front and rear casings together.
I got the CCD as square to the front surface as my super accurate cheapo plastic vernier gauge could measure - which should be around 0.05mm.
At first I was pretty angry with the poor design and construction. This is a relatively inexpensive CCD, but still, the design, construction and QC is clearly very poor.
But at least it was easy to fix. The fix is temporary, and I intend to get a suitable plastic spacer and spring for a more permanent fix. But if this kludgy fix holds for long enough, I expect it will remain until the CCD gets out of alignment enough to annoy me.
One good thing about the QHY8 is the rubber seal between the front and rear casings. This seems to do a good job of damping the vibrations from the fan.
For not much more cash than a modified DSLR, you get a compact, lightweight, cooled OSC camera with 16-bit output and a decent-sized CCD. Issues with the drivers seem to have been worked out, and I had no problems using the QHY8 with Nebulosity on my Mac. A new DSLR would have higher resolution, but that's not much of a benefit for astro imaging.
However, with the QHY8, at least the one I got, you do have to put up with dodgy design, cheap construction and poor quality control. If you don't like pulling things apart to fix them and don't have a local dealer to sort stuff out for you, I wouldn't recommend the QHY8. The Orion Starshoot Pro, settling for a smaller CCD, saving and holding out for a good deal on a used SBIG camera might be better options.
Now, I just need some clear skies to test the kludgy fix.
2009-10-10
More new toys
What is potentially the last "old new stock" Pentax 75-SDHF in Tokyo arrived today, along with some Borg parts, and a very nice ball head, all from Starbase Tokyo. The manager, Yamamoto-san very kindly helped me out by forwarding on a modded Canon 5D that I won on Yahoo auction.
The Borg bits should allow stacking filters behind a Canon mount attached to the QHY8. I will eventually post descriptions and tests. It's still cloudy here, so not much chance of testing out kit.
A Pentax 7x50 finder that I found on astromart also arrived.
I'm now nearly done with major kit purchases. Now I just need to find time to do some more imaging and tests.
The Borg bits should allow stacking filters behind a Canon mount attached to the QHY8. I will eventually post descriptions and tests. It's still cloudy here, so not much chance of testing out kit.
A Pentax 7x50 finder that I found on astromart also arrived.
I'm now nearly done with major kit purchases. Now I just need to find time to do some more imaging and tests.
2009-10-09
OM mount Sigma 400/5.6 APO
The UPS guy just dropped this off. It was on sale at 254 USD, plus 57.95 s&h at KEH. It's in excellent condition. My initial impression is that it's well built, tiny and light for a 400mm lens. Some quick daylight shots on an E-620 show good control of colour, but contrast is a bit lacking.
It goes into the pipeline to be tested for astro use.
It goes into the pipeline to be tested for astro use.
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