{"slug":"star-trails-howto","title":"星轨应该如何拍摄和后期","author":"Thomas看看世界","date":"2019-04-14","wechat":"https://mp.weixin.qq.com/s?__biz=MzI4NDA5MzE5NQ==&mid=2247488776&idx=1&sn=34e497561711c9a58ca657492c872e14&chksm=eb81eb6cdcf6627a9f4c61f9241d9a49e402c215258360e484d8f2dd9d73fe5bd4f2cfc8f5a6&scene=21#wechat_redirect","blocks":[{"t":"h","x":"Thomas看看世界","xe":"Thomas Chu Photo"},{"t":"p","x":"星空摄影是一件浪漫的事。来自数亿年前的星光，穿过茫茫宇宙，在cmos上堆积几十秒，才变成了一张送给人类的礼物。","b":false,"xe":"Astrophotography is a romantic pursuit. Starlight from hundreds of millions of years ago crosses the vast universe and piles onto the CMOS sensor for dozens of seconds before becoming a gift to humanity."},{"t":"p","x":"当我们用更长时间的曝光，或者把一段时间的星空照片叠加在一起，我们还能惊喜的发现时间的痕迹。摄影师把这样的照片称为星轨。","b":false,"xe":"With even longer exposures, or by stacking star photos taken over a period of time, we can delightfully discover the traces of time. Photographers call these images star trails."},{"t":"p","x":"今天他托马斯就会教大家，如何拍摄并叠加出一张星轨照片。","b":false,"xe":"Today Thomas will teach you how to shoot and stack a star-trail photo."},{"t":"img","f":"img-02","w":1080,"h":720},{"t":"h","x":"视频教程","xe":"Video tutorial"},{"t":"bili","bv":"BV1nb411T7t6","bpic":"bili-1","bt":"如何拍摄和后期制作星轨？？"},{"t":"p","x":"这一篇是上面视频的完整图文整理。Thomas 用一组实拍完整演示了星轨的前期拍摄和后期制作：从月相的选择、器材清单、与拍星空几乎相同的参数，到无穷远对焦和连拍，再到 Camera Raw 批量调整与 PS 变亮混合模式的合成。教程 11 分钟，图文版配上了全部关键步骤的截图。","xe":"This is the fully illustrated companion to the video above: with one live shoot, Thomas demonstrates star-trail shooting and processing end to end — choosing the moon phase, the gear list, settings nearly identical to ordinary astro shots, infinity focusing and continuous shooting, then batch edits in Camera Raw and the Lighten blend-mode stack in Photoshop. The 11-minute tutorial is laid out here with screenshots of every key step."},{"t":"img","f":"v01","w":852,"h":480},{"t":"p","x":"先看成片。上面这张星轨摄于印尼布罗莫火山：因为地球自转，星空时刻在运动，把连续拍摄的星空照片叠在一起，就能显出星星绕着北极星旋转的同心圆轨迹——这就是星轨拍摄的原理（视频 0:16 处）。","xe":"Start with the result: this star-trail image was shot over Mount Bromo in Indonesia. Because the Earth rotates, the stars never stop moving; stack a continuous sequence of astro frames and the stars trace concentric circles around Polaris — the very principle of star-trail photography (at 0:16 in the video)."},{"t":"h","x":"01 时机与器材：月相表和三样装备","xe":"01 Timing and Gear: The Moon Table and Three Essentials"},{"t":"p","x":"星轨有最佳拍摄时间。上网打开月相表就能查到（视频 0:36 处）：农历初一朔月前后七八天，天上完全没有月亮，星星过于密集，地景又没有月光补光；农历十五十六满月前后则相反，月光太强，几乎看不到几颗星星——两头都不合适。最好的窗口是月亮只露一半的时候，从四分之一月到四分之三月之间：星星密度适中，地景又有月光照亮（视频 1:17 处）。","xe":"Star trails have an ideal window, and an online moon-phase table tells you when (at 0:36 in the video). The seven or eight days around the new moon leave a moonless sky: stars crowd too densely and the landscape gets no fill light; around the full moon the opposite problem hits — moonlight so strong that only a handful of stars show. The sweet spot is a half-lit moon, anywhere between quarter and three-quarter phases: moderate star density plus moonlit foreground (at 1:17 in the video)."},{"t":"img","f":"v02","w":852,"h":480},{"t":"p","x":"器材比想象中简单：一支三脚架（星轨需要长时间曝光）、一台单反或无反相机——如今甚至手机也能拍星空——以及一支尽量大光圈的广角镜头，f/2.8 最推荐，f/4、f/4.5 也可以（视频 1:41 处）；再加一部手机或快门线做遥控，和一台性能足够的后期电脑。","xe":"The gear is simpler than expected: a tripod for the long continuous shoot; a DSLR or mirrorless camera — even a phone can shoot the stars nowadays; and the widest-aperture wide-angle lens you can get, f/2.8 ideal, f/4 or f/4.5 acceptable (at 1:41 in the video); plus a phone or cable release for remote control, and a capable computer for post."},{"t":"img","f":"v03","w":852,"h":480},{"t":"img","f":"v04","w":852,"h":480},{"t":"h","x":"02 拍摄：对准北方，参数照搬拍星空","xe":"02 Shooting: Face North, Reuse Your Astro Settings"},{"t":"p","x":"北半球的星轨是以北极星为圆心的一个个圆环，南半球则以南天极为圆心（视频 2:33 处）。所以对准正北方拍摄能得到完整的同心圆，对准其他方向得到的则是不完整的弧线——两种都好看，看你想要哪种效果。","xe":"In the northern hemisphere star trails are circles centered on Polaris; in the southern hemisphere they center on the south celestial pole (at 2:33 in the video). Point the camera due north for complete concentric circles; any other direction yields partial arcs — both look great, depending on the effect you want."},{"t":"img","f":"v05","w":852,"h":480},{"t":"p","x":"最简单的参数方案，就是照搬你拍星空的设置（视频 3:00 处）：快门 30 秒、光圈开到最大的 f/2.8、ISO 3200 左右，太亮或太暗再微调。唯一不同的是白平衡——从自动改成固定 K 值，3500 到 4500 都可以，只要全程保持一致，否则叠加出的星轨会颜色跳变（视频 3:39 处）。","xe":"The simplest settings plan is to copy your regular astro setup (at 3:00 in the video): 30-second shutter, aperture wide open at f/2.8, ISO around 3200, fine-tuning only if the result is too bright or dark. The one difference is white balance — switch from auto to a fixed Kelvin value, anywhere from 3500 to 4500, just keep it constant throughout, or the stacked trails will shift in color (at 3:39 in the video)."},{"t":"img","f":"v06","w":852,"h":480},{"t":"p","x":"对焦到无穷远也不难：把相机背屏画面放大，找一颗亮星、远处的月亮或路灯，切到手动对焦，慢慢转动对焦环——星星会先变虚、到无穷远附近越来越实，最实的那一刻停下就完成了（视频 4:18 处）。设置完毕后开启连拍：15-20 分钟就有不错的结果，推荐拍 30 分钟到一小时，轨迹更长、更壮观（视频 4:45 处）。","xe":"Focusing at infinity is straightforward too: magnify the live view on the back screen, pick a bright star, the moon or a distant lamp, switch to manual focus, and rotate the focus ring slowly — the star blurs first, then sharpens as you approach infinity; stop at the sharpest point (at 4:18 in the video). With settings locked, start the interval burst: 15-20 minutes already gives decent results, and 30 minutes to an hour — recommended — draws longer, grander trails (at 4:45 in the video)."},{"t":"img","f":"v07","w":852,"h":480},{"t":"h","x":"03 批量调整：Camera Raw 同步设置","xe":"03 Batch Editing: Sync Settings in Camera Raw"},{"t":"p","x":"大概 20 分钟后就能得到 40 张左右的星空照片（视频 5:02 处）。后期第一步在 Bridge 里全选这组照片，右键在 Camera Raw 中打开，先处理其中一张，再把调整同步到全部（视频 5:29 处）。","xe":"About 20 minutes of shooting yields roughly 40 star frames (at 5:02 in the video). Post starts in Bridge: select the whole set, right-click to open in Camera Raw, edit one frame, then sync the adjustments across all of them (at 5:29 in the video)."},{"t":"img","f":"v08","w":852,"h":480},{"t":"p","x":"单张的调整思路：原照色温稍偏暖，就往左移一点让夜空变蓝（视频 5:40 处）；30 秒长曝后曝光仍略欠，稍作提升；对比度微升，阴影提亮一点避免画面太黑。高光则反其道而行——普通照片压高光，星轨照片反而把高光提上去，让星星更亮（视频 6:25 处）；再来一点去除薄雾，星星立刻更明显（视频 6:33 处）；最后用曲线把最暗部稍稍提亮，消除死黑。别忘了删除色差和启动镜头配置文件校正，暗角修复拉到 80 左右就够了（视频 6:56 处）。调整完全选、同步设置，40 张一次搞定（视频 7:21 处）。","xe":"The per-frame recipe: nudge the slightly warm temperature left until the night sky turns blue (at 5:40 in the video); lift exposure a touch, since even 30 seconds runs a little short; raise contrast slightly and brighten shadows so the frame never goes muddy. Highlights go against habit — instead of pulling them down as in normal photos, push them up a little to make the stars brighter (at 6:25 in the video); a touch of Dehaze makes the stars pop immediately (at 6:33 in the video); finish with a curve lifting the deepest shadows to kill any dead black. Do not forget Remove Chromatic Aberration and lens-profile corrections, with vignette correction dialed back to about 80 (at 6:56 in the video). Then select all, sync settings, and all 40 frames are done at once (at 7:21 in the video)."},{"t":"img","f":"v09","w":852,"h":480},{"t":"h","x":"04 合成：变亮混合模式一步出星轨","xe":"04 The Stack: Lighten Blend Draws the Trails"},{"t":"p","x":"接下来在 PS 里打开这组调整好的照片：执行「文件 → 脚本 → 将文件载入堆栈」，浏览全选后确定（视频 8:14 处）。内存不大的电脑建议先把 RAW 存成 JPEG 再导入，速度更快也不容易死机；视频里 40 张 RAW 文件直接打开没有任何问题。全部载入后，选中第一个图层，按住 Shift 点最下面一个图层，全选所有图层（视频 8:36 处）。","xe":"Next, open the edited set in Photoshop: run File → Scripts → Load Files into Stack, browse, select all and confirm (at 8:14 in the video). On a low-memory machine it is wise to convert the RAWs to JPEG first for speed and stability; in the video the 40 RAW files load directly without any trouble. Once loaded, click the top layer, Shift-click the bottom one, and select every layer (at 8:36 in the video)."},{"t":"p","x":"然后把混合模式从「正常」改成「变亮」——星轨立刻就出来了（视频 8:56 处）。Thomas 推荐用变亮混合而不是最大值堆栈来合成星轨：它调整起来非常灵活。比如发现某段星轨断开了、上面突然多出一堆星点，说明拍摄中间有过停顿——把最上面几个图层挨个隐藏排查，藏掉断档前后的三张，断线问题就解决了（视频 9:32 处）。最后右键合并图层，再用曲线、色阶等工具进一步调色，一张记录了地球自转轨迹的星轨照片就完成了（视频 10:16 处）。","xe":"Then change the blend mode from Normal to Lighten — the star trails appear instantly (at 8:56 in the video). Thomas recommends Lighten blending over a maximum-value stack for trails: it is far more flexible to adjust. Say a section of trail breaks, with a sudden burst of dots above it — that means the shooting paused mid-sequence. Hide the top layers one by one to find the culprit; tucking away the three frames around the gap fixes the break (at 9:32 in the video). Finally right-click to merge the layers, refine color with curves and levels, and a star-trail image that records the Earth's rotation is complete (at 10:16 in the video)."},{"t":"img","f":"v10","w":852,"h":480},{"t":"img","f":"v11","w":852,"h":480},{"t":"img","f":"v12","w":852,"h":480},{"t":"quote","x":"1. 选月相比选天气还重要：朔月前后太密、满月前后太亮，月亮露一半的四分之一到四分之三月初最佳；2. 参数照搬拍星空——30 秒、f/2.8、ISO 3200，唯一区别是白平衡锁定固定 K 值，然后对无穷远手动对焦、开启连拍 30 分钟以上；3. 后期先在 Camera Raw 里同步好全部单张，再「将文件载入堆栈」全选图层改「变亮」混合模式，星轨即成；4. 变亮混合比最大值堆栈更灵活，出现断轨就隐藏图层排查补拍前后的帧，轻松修复。","xe":"1. Choosing the moon phase matters as much as choosing the weather: too many stars near the new moon, too much light near the full — a half-lit moon between quarter and three-quarter phases is best; 2. Reuse your astro settings — 30 s, f/2.8, ISO 3200 — with the one change of locking white balance to a fixed Kelvin value, then focus manually at infinity and run the burst for 30 minutes or more; 3. In post, sync every frame in Camera Raw, Load Files into Stack, select all layers and switch to Lighten — the trails appear; 4. Lighten blending is more flexible than a maximum stack: if a trail breaks, hide layers to find the frames around the pause and the gap repairs easily."},{"t":"p","x":"高清视频：","b":false,"xe":"HD video:"},{"t":"h","x":"https://www.bilibili.com/video/av49260086/","xe":"https://www.bilibili.com/video/av49260086/"},{"t":"h","x":"文字大纲","xe":"Written Outline"},{"t":"p","x":"1. 因为地球自转的原因，星空其实是在一直转动的。所以我们使用长曝光的方式，比如B门曝光15分钟以上，就能拍出漂亮的星轨。","b":false,"xe":"1. Because of Earth's rotation, the starry sky is constantly turning. So with a long exposure — for example, a Bulb exposure of 15 minutes or more — you can capture beautiful star trails."},{"t":"img","f":"img-03","w":1080,"h":717},{"t":"p","x":"不过摄影师一般更喜欢通过设置普通拍星参数，连续拍摄多张叠加的方式，这种方法有以下好处：","b":false,"xe":"However, photographers generally prefer shooting a continuous series with normal astrophotography settings and stacking them, for the following reasons:"},{"t":"p","x":"1) 可以有效防止长曝光噪点。而且多张照片叠加后的噪点并不会很多。","b":false,"xe":"1) It effectively prevents long-exposure noise, and the stacked result doesn't accumulate much noise either."},{"t":"p","x":"2）因为是普通拍星参数。如果我们只取一张处理，就能得到漂亮的普通星空。如果我们把一系列照片连续放映，还能做成延时视频。","b":false,"xe":"2) Since normal star settings are used, any single frame can be processed into a beautiful regular night-sky photo, and playing the whole series in sequence makes a time-lapse video."},{"t":"p","x":"3）如果中途有1，2张发生意外，如突然的灯光污染、镜头被挡等，不会导致整组照片被毁。","b":false,"xe":"3) If one or two frames go wrong mid-sequence — sudden light pollution, a blocked lens — the whole set isn't ruined."},{"t":"img","f":"img-04","w":1080,"h":516},{"t":"p","x":"2. 星轨照片最好避开满月（农历十五）前后几天，因为月光太强，星星看不到几颗。","b":false,"xe":"2. It's best to avoid the days around the full moon (the 15th of the lunar month) for star trails, because the moonlight is too strong and only a few stars are visible."},{"t":"p","x":"星轨照片也最好避开新月（农历初一）前后几天，因为地景很暗，而且星星会过于密集。","b":false,"xe":"It's also best to avoid the days around the new moon (the 1st of the lunar month), because the foreground is very dark and the stars become overly dense."},{"t":"p","x":"一个月的其他时间，也就是月亮露出来一部分的时候，更加适合拍摄星轨，此时星星密度合适，地景也能被月光照亮。","b":false,"xe":"The rest of the month, when part of the moon is showing, is more suitable for star trails: star density is just right and the foreground is lit by moonlight."},{"t":"img","f":"img-05","w":988,"h":915},{"t":"p","x":"3. 星轨拍摄，单张参数一般和星空拍摄相同，月光较弱时大概在ISO3200 f2.8 30s，月光较好时ISO 800 f4 30s就足够了。实际拍摄时，大家可以先拍1张，再根据直方图和效果调整参数。","b":false,"xe":"3. For star trails, single-frame settings are generally the same as for star photography: around ISO 3200, f/2.8, 30s under weak moonlight; ISO 800, f/4, 30s is enough under brighter moonlight. In the field, take one test shot first, then adjust settings based on the histogram and the result."},{"t":"p","x":"白平衡可以手动设置到3500-4000之间，保持系列照片间统一。拍摄时可以用快门线，设置定时间隔连拍，当然最简单的方式，就是设置成连拍模式，然后用快门线或者APP长按快门，相机就会一直拍下去了。","b":false,"xe":"White balance can be set manually between 3500-4000K and kept consistent across the series. For shooting, use a shutter release cable with an interval timer — or simplest of all, set the camera to continuous drive and hold the shutter down with a cable release or app, and the camera will keep shooting."},{"t":"p","x":"一般15-60分钟的连续拍摄，就能得到不错的星轨了。","b":false,"xe":"Generally, 15-60 minutes of continuous shooting yields a nice star trail."},{"t":"img","f":"img-06","w":972,"h":821},{"t":"p","x":"4. 星轨对焦，需要手动对焦。方法是使用相机机背屏幕，找到一颗亮星（或远处的灯光、月亮），调整对焦环直至亮星从模糊状态变成一颗小点。","b":false,"xe":"4. Star-trail focusing requires manual focus. Use the camera's rear screen to find a bright star (or a distant light, or the moon), and turn the focus ring until the bright star goes from blurry to a tiny sharp point."},{"t":"p","x":"对于大部分镜头而言，对焦环转到最远，并不是准确的无穷远。可以看到星星还是虚的。","b":false,"xe":"For most lenses, turning the focus ring all the way to the far end is not accurate infinity — the star will still look soft."},{"t":"img","f":"img-07","w":1080,"h":609},{"t":"p","x":"一般都是要从最远回来一点点，才是真正对焦到了无穷远，星星显示为实心。","b":false,"xe":"Usually you need to come back slightly from the far end to truly reach infinity focus, at which point the star appears as a solid point."},{"t":"img","f":"img-08","w":1080,"h":514},{"t":"p","x":"5. 在北半球对准北方拍摄，可以拍到以北极星为圆心的同心圆星轨。在南半球，对准南方可以拍到同心圆星轨。","b":false,"xe":"5. In the Northern Hemisphere, aiming north captures concentric circular star trails centered on Polaris. In the Southern Hemisphere, aim south for concentric circles."},{"t":"img","f":"img-09","w":1080,"h":717},{"t":"p","x":"如果对准其他方向，我们也能拍到圆心在画面外的环状星轨。","b":false,"xe":"Aiming in other directions also produces arc-shaped trails whose center lies outside the frame."},{"t":"img","f":"img-10","w":1080,"h":717},{"t":"p","x":"6. 星轨的后期处理，我们首先要对其中一张，进行基本的Camera Raw曝光调整，然后同步到该系列的全部照片上。","b":false,"xe":"6. For star-trail post-processing, first apply basic Camera Raw exposure adjustments to one frame, then sync them across the entire series."},{"t":"img","f":"img-11","w":1080,"h":606},{"t":"p","x":"如果照片过多或者修图电脑内存较小，建议在Camera Raw里以JPEG格式导出系列照片。","b":false,"xe":"If there are too many photos or your editing computer has limited memory, export the series as JPEGs from Camera Raw."},{"t":"p","x":"7. 在Photoshop中，加载全部图片到文件中，把层混合模式改成“变亮”，好看的星轨就生成啦。","b":false,"xe":"7. In Photoshop, load all the images into one file and set the layer blend mode to \"Lighten\" — beautiful star trails appear."},{"t":"p","x":"星轨拍摄和后期并不复杂， 城市中也可以拍到，大家赶快试试吧。","b":false,"xe":"Star-trail shooting and editing are not complicated, and you can even do it in the city. Give it a try!"},{"t":"p","x":"欢迎大家把拍到的星轨和星空照片，投稿到微博 #510100公里# 话题。","b":false,"xe":"You're welcome to submit your star-trail and night-sky photos to the Weibo hashtag #510100公里#."},{"t":"img","f":"img-12","w":872,"h":680}],"titleEn":"How to Shoot and Edit Star Trails"}