How to shoot the galaxy starry sky
Text/Jetty
Shooting equipment: Sony Micro single A7R2 / old frog 12mmF2.8 lens
Shooting parameters: Shutter 10 seconds / Aperture F2.8 / ISO6400 / Focus manual infinity /
Location: Yumenguan, Dunhuang
01, how can I capture a clear galaxy?
First of all, we must abide by it, that is, we can only see the Milky Way with the naked eye, and we can shoot the Milky Way. If the light pollution is serious, or the weather is bad (such as fog, thick clouds, rain), it is almost impossible to shoot.
Therefore, if you want to shoot the Galaxy Starry Sky, you must do a good job in weather forecasting. In addition, the moon phase is also the size of the moon will also affect the shooting of the starry sky, the moon's light is too bright, will make the Milky Way less obvious. Usually in the first day of the lunar calendar, it is better to shoot when the moon is a new moon or crescent.
Here are two mobile apps:
StarLive - tells you a score straight away, generally 70 points or more can basically try to shoot the Galaxy, the probability of success is high.
Ink weather - understand the local weather conditions, if the rainy days do not delay work.
02, how to determine the location of the galaxy
Even with very good weather and star-gazing index, the galaxy seen by the naked eye is always vague, and the galaxy will slowly change position over time. Below we need to use an APP to determine the location of the galaxy.
StarWalk2 - This software, open the gyroscope, move the location of the phone, you can find the location where the Galaxy is now, then open the timeline function, look at which direction the Galaxy will shift in a moment, so that we can compose the picture.
03, the determination of the shooting parameters
Aperture: F2.8 First M file, determine the aperture, in general, the light of the Milky Way is very dark, we need to use the maximum aperture of the lens, my old frog 12mmF2.8, I will set the aperture to 2.8.
Shutter: 25 seconds is followed by determining the shutter speed. Since the Milky Way and the stars are actually moving slowly, there is a 500 theorem. First of all, you need to know what the focal length of your shooting is (the focal length must be converted to 135 full-length focal length), my 12mm fixed-focus head is 12mm, if it is a zoom head, then the general shooting Galaxy is also the most wide-angle end, the focal length The paragraph is optimistic. If it is an APS-C machine, for example, if you use a 24-105 lens, then your actual full-scale conversion focal length is 24*1.5 (the coefficient is determined by the camera) = 36mm. What does the 500 law mean? With 500 removed my shooting focal length of 12mm, equal to 41.6, then your shutter speed can not be slower than 41.6 seconds. Because the speed is slower than this value, the star will have a small tail on the photo (because the star moved during the exposure shooting), I chose the shutter for 10 seconds. Later, I found this to be an error. In fact, it should be set to 25-30 seconds. Because the actual exposure of the RAW photo of the 10 second exposure is insufficient, I need to brighten it during the post processing. As soon as the result is brightened, the noise is out. Therefore, when paying attention to shooting the Galaxy, shoot the RAW format, and turn off the noise reduction inside the machine, so as not to affect your judgment. I was misled by the noise reduction inside the machine. I saw that the small screen felt the photo was bright enough, but the small screen could not reflect the real situation of the noise at that time.
ISO: 6400 When the first two items are confirmed, try to lower the ISO as high ISO will generate noise. At the same time, you need to know the maximum ISO available for your device. My Sony A7R2 is generally available to 6400. If it is high, the noise will be more obvious and it will be difficult to reduce noise later.
Focus: Manual focus to infinity, but here you can also directly focus on the foreground, because it is usually shot with super wide angle, so the actual situation is to focus on the foreground, due to the wide angle, the depth of field is very large, the sky is also real Defocused.
Then take a test shot based on this parameter, and then fine-tune the shutter and ISO parameters. Whether the exposure is accurate or not depends on the brightness of the histogram. Generally, the histogram should be at least close to the middle. The early exposure is sufficient, and the exposure is not required to be greatly enlarged in the later stage to avoid the occurrence of noise. Of course, there are still many variables in the actual situation. Everyone is tempted to adapt, or to take several sets of different exposure values ​​for later retouching.
In fact, the 500 law is not accurate, there are 400 laws and 600 laws, the smaller the number, the smaller the possibility of tailing, but the shorter the shutter time used, in this case, the performance of the camera is higher. Because the shutter time is short, if the exposure is insufficient, a higher ISO is required, and in the case of high ISO, the noise is difficult to suppress. It is recommended to shoot the Galaxy with a full-size SLR, a wide-angle lens with a size of 24mm or less, and a stable tripod.
Finally, if you want to take time-lapse photography of the Milky Way, then set the interval time. Generally, the shorter the interval, the better, because the exposure time itself is very long, reduce the interval, you can take as many photos as possible. Ensure that the length of the delayed video is sufficient.
Flying hand course subscription
Jetty will update the aerial course from time to time, and interested friends can identify us on the right QR code.
SPD Surge Protective Device,Lightning Surge Protector
Surge Protection Device (SPD)
It is a device used to limiting instant surge voltage and discharge surge current, it at least including a non-linear component.
Surge protective Device Model Selection
With the impact of international information flow, the rapid development of microelectronic science and technology, communication, computer and automatic control technology, make the building start to go for high quality, high functional area, formed a new building style-intelligent building. As inside the intelligent building there are lot of information system, <<Building lightning protection design norm>> GB50057-94(2002 vision)(hereafter brief as <<lightning protection norm>>) put forward the relative requirement to install the surge protective device, to ensure the information system safely and stable running.
SPD essentially is a equipotential connection material, its model selection is according to the different lightning protection area, different lightning electromagnetic pulse critical and different equipotential connection position, decide which kind of SPD used in the area, to achieve the equipotential connection with the common earth electrode. Our statement will based on SPD's maximum discharge current Imax, continuous operating voltage Uc, protection voltage Up, alarm mode etc.
As per << Lightning Protection Norm>> item 6.4.4 stipulation "SPD must can withstand the expected lightning current flow and should confirm to the additional two requirements: the maximum clamp voltage during surge across, capable to extinguish the power frequency follow-on current after lightning current across." That is the value of SPD's max. clamp voltage add its induction voltage of two ends should be same with the system's basic insulation level and the equipment allowed max. surge voltage.
SPD for Power Supply System Series Selection Guide
The installation of SPD at each lightning protection zone, according to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category, its insulation withstand impulse voltage level can determine the selection of SPD. According to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category as signal level, loading level, distribution and control level, power supply level. Its insulation withstand impulse voltage level are:1500V,2500V,4000V,6000V. As per to the protected equipment installation position different and the different lightning current of different lightning protection zone, to determine the installation position of SPD for power supply and the break-over capacity.
The installation distance between each level SPD should not more than 10m, the distance between SPD and protected equipment should as short as possible, not more than 10m. If due to limitation of installation position, can't guarantee the installation distance, then need to install decoupling component between each level SPD, make the after class SPD can be protected by the prior class SPD. In the low voltage power supply system, connecting an inductor can achieve the decoupling purpose.
SPD for power supply system specification selection principle
Max. continuous operating voltage: bigger than protected equipment, the system's max. continuous operating voltage.
TT System: Uc≥1.55Uo (Uo is low voltage system to null line voltage)
TN System: Uc≥1.15Uo
IT System: Uc≥1.15Uo(Uo is low voltage system to line voltage)
Voltage Protection Level: less than the insulation withstand impulse voltage of protected equipment
Rated discharge current: determined as per to the lightning situation of the position installed and lightning protection zone.
SP1 Series
Normal Working Conditions
-Altitude not exceed 2000m
-Ambient air temperature:
Normal range: -5ºC~+40ºC
Extend range: -40ºC~+80ºC
-Relative Humidity: 30% - 90% under indoor temperature condition
- At the place without obviously shaking and shock vibration
- Non-explosion danger medium, non-corrosion gas and dust ( including conductive dust)
Classification
-As per Nominal Discharge Current:
5,10,20,30,40,60KA(8/20µs)
- As per Maximum continuous operating voltage:
275V,320V,385V,420V,440V,460V
- As per to poles
1P,1P+N,2P,3P,3P+N,4P
- As per auxiliary functions:
a. With remote signal output ( remote alarm function)
b. Without remote signal output
Selection Principle
- The continuous applied voltage on the two terminals of SPD should not more than the maximum continuous operating voltage Uc value;
- The voltage protection level Up of SPD should less than the maximum impulse withstand voltage of the protected equipment;
- As per to the different earthing system and protection mode to select the specification accordingly;
Text/Jetty
Shooting equipment: Sony Micro single A7R2 / old frog 12mmF2.8 lens
Shooting parameters: Shutter 10 seconds / Aperture F2.8 / ISO6400 / Focus manual infinity /
Location: Yumenguan, Dunhuang
01, how can I capture a clear galaxy?
First of all, we must abide by it, that is, we can only see the Milky Way with the naked eye, and we can shoot the Milky Way. If the light pollution is serious, or the weather is bad (such as fog, thick clouds, rain), it is almost impossible to shoot.
Therefore, if you want to shoot the Galaxy Starry Sky, you must do a good job in weather forecasting. In addition, the moon phase is also the size of the moon will also affect the shooting of the starry sky, the moon's light is too bright, will make the Milky Way less obvious. Usually in the first day of the lunar calendar, it is better to shoot when the moon is a new moon or crescent.
Here are two mobile apps:
StarLive - tells you a score straight away, generally 70 points or more can basically try to shoot the Galaxy, the probability of success is high.
Ink weather - understand the local weather conditions, if the rainy days do not delay work.
02, how to determine the location of the galaxy
Even with very good weather and star-gazing index, the galaxy seen by the naked eye is always vague, and the galaxy will slowly change position over time. Below we need to use an APP to determine the location of the galaxy.
StarWalk2 - This software, open the gyroscope, move the location of the phone, you can find the location where the Galaxy is now, then open the timeline function, look at which direction the Galaxy will shift in a moment, so that we can compose the picture.
03, the determination of the shooting parameters
Aperture: F2.8 First M file, determine the aperture, in general, the light of the Milky Way is very dark, we need to use the maximum aperture of the lens, my old frog 12mmF2.8, I will set the aperture to 2.8.
Shutter: 25 seconds is followed by determining the shutter speed. Since the Milky Way and the stars are actually moving slowly, there is a 500 theorem. First of all, you need to know what the focal length of your shooting is (the focal length must be converted to 135 full-length focal length), my 12mm fixed-focus head is 12mm, if it is a zoom head, then the general shooting Galaxy is also the most wide-angle end, the focal length The paragraph is optimistic. If it is an APS-C machine, for example, if you use a 24-105 lens, then your actual full-scale conversion focal length is 24*1.5 (the coefficient is determined by the camera) = 36mm. What does the 500 law mean? With 500 removed my shooting focal length of 12mm, equal to 41.6, then your shutter speed can not be slower than 41.6 seconds. Because the speed is slower than this value, the star will have a small tail on the photo (because the star moved during the exposure shooting), I chose the shutter for 10 seconds. Later, I found this to be an error. In fact, it should be set to 25-30 seconds. Because the actual exposure of the RAW photo of the 10 second exposure is insufficient, I need to brighten it during the post processing. As soon as the result is brightened, the noise is out. Therefore, when paying attention to shooting the Galaxy, shoot the RAW format, and turn off the noise reduction inside the machine, so as not to affect your judgment. I was misled by the noise reduction inside the machine. I saw that the small screen felt the photo was bright enough, but the small screen could not reflect the real situation of the noise at that time.
ISO: 6400 When the first two items are confirmed, try to lower the ISO as high ISO will generate noise. At the same time, you need to know the maximum ISO available for your device. My Sony A7R2 is generally available to 6400. If it is high, the noise will be more obvious and it will be difficult to reduce noise later.
Focus: Manual focus to infinity, but here you can also directly focus on the foreground, because it is usually shot with super wide angle, so the actual situation is to focus on the foreground, due to the wide angle, the depth of field is very large, the sky is also real Defocused.
Then take a test shot based on this parameter, and then fine-tune the shutter and ISO parameters. Whether the exposure is accurate or not depends on the brightness of the histogram. Generally, the histogram should be at least close to the middle. The early exposure is sufficient, and the exposure is not required to be greatly enlarged in the later stage to avoid the occurrence of noise. Of course, there are still many variables in the actual situation. Everyone is tempted to adapt, or to take several sets of different exposure values ​​for later retouching.
In fact, the 500 law is not accurate, there are 400 laws and 600 laws, the smaller the number, the smaller the possibility of tailing, but the shorter the shutter time used, in this case, the performance of the camera is higher. Because the shutter time is short, if the exposure is insufficient, a higher ISO is required, and in the case of high ISO, the noise is difficult to suppress. It is recommended to shoot the Galaxy with a full-size SLR, a wide-angle lens with a size of 24mm or less, and a stable tripod.
Finally, if you want to take time-lapse photography of the Milky Way, then set the interval time. Generally, the shorter the interval, the better, because the exposure time itself is very long, reduce the interval, you can take as many photos as possible. Ensure that the length of the delayed video is sufficient.
Flying hand course subscription
Jetty will update the aerial course from time to time, and interested friends can identify us on the right QR code.
Product Description
SPD Surge Protective Device,Lightning Surge Protector
Surge Protection Device (SPD)
It is a device used to limiting instant surge voltage and discharge surge current, it at least including a non-linear component.
Surge protective Device Model Selection
With the impact of international information flow, the rapid development of microelectronic science and technology, communication, computer and automatic control technology, make the building start to go for high quality, high functional area, formed a new building style-intelligent building. As inside the intelligent building there are lot of information system, <<Building lightning protection design norm>> GB50057-94(2002 vision)(hereafter brief as <<lightning protection norm>>) put forward the relative requirement to install the surge protective device, to ensure the information system safely and stable running.
SPD essentially is a equipotential connection material, its model selection is according to the different lightning protection area, different lightning electromagnetic pulse critical and different equipotential connection position, decide which kind of SPD used in the area, to achieve the equipotential connection with the common earth electrode. Our statement will based on SPD's maximum discharge current Imax, continuous operating voltage Uc, protection voltage Up, alarm mode etc.
As per << Lightning Protection Norm>> item 6.4.4 stipulation "SPD must can withstand the expected lightning current flow and should confirm to the additional two requirements: the maximum clamp voltage during surge across, capable to extinguish the power frequency follow-on current after lightning current across." That is the value of SPD's max. clamp voltage add its induction voltage of two ends should be same with the system's basic insulation level and the equipment allowed max. surge voltage.
SPD for Power Supply System Series Selection Guide
The installation of SPD at each lightning protection zone, according to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category, its insulation withstand impulse voltage level can determine the selection of SPD. According to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category as signal level, loading level, distribution and control level, power supply level. Its insulation withstand impulse voltage level are:1500V,2500V,4000V,6000V. As per to the protected equipment installation position different and the different lightning current of different lightning protection zone, to determine the installation position of SPD for power supply and the break-over capacity.
The installation distance between each level SPD should not more than 10m, the distance between SPD and protected equipment should as short as possible, not more than 10m. If due to limitation of installation position, can't guarantee the installation distance, then need to install decoupling component between each level SPD, make the after class SPD can be protected by the prior class SPD. In the low voltage power supply system, connecting an inductor can achieve the decoupling purpose.
SPD for power supply system specification selection principle
Max. continuous operating voltage: bigger than protected equipment, the system's max. continuous operating voltage.
TT System: Uc≥1.55Uo (Uo is low voltage system to null line voltage)
TN System: Uc≥1.15Uo
IT System: Uc≥1.15Uo(Uo is low voltage system to line voltage)
Voltage Protection Level: less than the insulation withstand impulse voltage of protected equipment
Rated discharge current: determined as per to the lightning situation of the position installed and lightning protection zone.
SP1 Series
Normal Working Conditions
-Altitude not exceed 2000m
-Ambient air temperature:
Normal range: -5ºC~+40ºC
Extend range: -40ºC~+80ºC
-Relative Humidity: 30% - 90% under indoor temperature condition
- At the place without obviously shaking and shock vibration
- Non-explosion danger medium, non-corrosion gas and dust ( including conductive dust)
Classification
-As per Nominal Discharge Current:
5,10,20,30,40,60KA(8/20µs)
- As per Maximum continuous operating voltage:
275V,320V,385V,420V,440V,460V
- As per to poles
1P,1P+N,2P,3P,3P+N,4P
- As per auxiliary functions:
a. With remote signal output ( remote alarm function)
b. Without remote signal output
Selection Principle
- The continuous applied voltage on the two terminals of SPD should not more than the maximum continuous operating voltage Uc value;
- The voltage protection level Up of SPD should less than the maximum impulse withstand voltage of the protected equipment;
- As per to the different earthing system and protection mode to select the specification accordingly;
Product Features
1, built-in over-current overheating, temperature control circuit technology.
2, the module design, easy installation, online replacement.
3, low leakage current, fast response time, low residual voltage.
4, alarm indication device, green (normal) v red (fault).
| Model/Technical Parameters | WR-B60 | WR-B80 | WR-B100 | WR-B120 | WR-B150 |
| Rated Operating Voltage Un (V ~) | 220V 380V | 220V 380V | 220V 380V | 220V 380V | 220V 380V |
| Maximum Continuous Operating Voltage Uc (V ~) kV | 385V 420V | 385V 420V | 385V 420V | 385V 420V | 385V 420V |
| Voltage Protection Level Up (V ~) kV | ≤1.8≤2.2 | ≤2.4≤2.5 | ≤2.5≤3.2 | ≤3.4≤3.7 | ≤4.0≤4.5 |
|
Maximum Discharge Current Imax(8/μ20μs)kA |
60 | 80 | 100 | 120 | 150 |
|
Nominal Discharge Current In(8/μ20μs)kA |
30 | 40 | 60 | 80 | 100 |
| Response Time | <25 | <100 | |||
| L/N(mm²)The Cross Section Of L/N Line | 16,25 | 16,25 | 16,25 | 16,25 | 25,35 |
| PE (mm²)The Cross Section Of PE Line | 16,25 | 25,35 | 25,35 | 25,35 | 35 |
| Fuse or Switch (A) | 63A | 63A | 63A,100A | 63A,100A | 63A,125A |
| The Line Section of Communication and Alarm (mm²) | ≥ 1.5 | ||||
|
Operating Environment-C |
(-40ºC~-+85ºC) | ||||
| Relative humidity 25 ºC | ≤95% | ||||
| installation | Standard Rail35mm | ||||
| Material of Outer Covering | Fiber Glass Reinforced Plastic | ||||
Surge Protector SPD,Surge Protection Device SPD,SPD
Wenzhou Korlen Electric Appliances Co., Ltd. , https://www.zjmotorstarter.com