"Skyflow" - a brief field test

The following brief time lapse video segments were captured and created using "Skyflow," an Apple iOS app running on my Apple iPad mini 6. My goal was simple: Capture a time lapse using the "RAW+JPEG" photo setting that could be used for testing purposes. In particular, I wanted to experiment with in-app editing of RAW files.

Here's the JPEG version of the time lapse video exported "as is" from "Skyflow."

27 February 2026. Video created using JPEG files.

Here's the JPEG version of the time lapse video exported from "Skyflow" and edited using Apple "Photos."

27 February 2026. Video created using JPEG files, edited using Apple "Photos."

And here's the version created using RAW files (negatives/DNGs) post-processed using the "Skyflow" in-app editor. My objective was to make the RAW version look as good or better than the JPEG version edited using Apple "Photos."

27 February 2026. Video created using RAW files.

Looking at the JPEG and RAW versions of the same video side-by-side, I think the JPEG version looks slightly better, and the JPEG version edited with "Photos" looks the best of all three. That tells me my "recipe" for in-app editing of RAW files probably needs to be tweaked for better results.

The following photo shows the first frame of the RAW files before it was edited. Notice the RAW image looks "flat" and washed out. The RAW files have much more dynamic range than the JPEGs shot at the same time, so it should be possible to edit them to look better than the JPEGs.

HEIC image saved from RAW video before editing.

Finally, here's the "recipe" I used to edit the RAW files using the in-app editor.

• Brightness = +/-0
• Contrast = +14
• Gamma = +/-0
• Shadows = +14
• Highlights = -14
• Black Point = +/-0
• Saturation = +26
• Vibrancy = +14
• Noise Reduction + 0
• Sharpness = 8
• Vignette = 0

Please comment on this blog post if you have suggestions for improving my "recipe." Thanks!

Tech Tips

The Apple "Camera" app on iPad mini 6 IS NOT CAPABLE of shooting RAW files (negatives/DNGs). Yet "Skyflow" can, and it uses the iPad camera. What's wrong with this picture? Hey Apple -- are you listening? This problem needs to be fixed STAT!

Among many nice features in "Skyflow," lots of useful information is available by tapping on a recording to open in "project view" (my name for the screen) and tapping the "i" button shown in the upper-left corner. In this case, I am reminded the app was set for Focus = Locked, Exposure = Auto, and White Balance = Locked.

"Skyflow" (i)nfo.

Nothing But Blue Skies ... well, almost

In my last blog post, I described how to interpret the "Sky Cond." shown in a table of three-day weather observations for KDCA on 27 February 2026 nearest the time when I recorded the time lapse video (shown above). The low level clouds shown in the video are fair weather cumulus (Cu).

Source Credit: KDCA | National Weather Service.

Related Resources 

• GoPro "Orbit" - a blog post by Walter Sanford
• [Blog] posts with label "Skyflow"

Copyright © 2026 by Walter Sanford. All rights reserved.

GoPro "Orbit"

The following panoramic time lapse video shows the sky over Fairfax County, Virginia USA during the afternoon of 27 February 2026. The sky is most mostly clear except for a few low level cumuliform clouds.

The video was recorded using my GoPro HERO4 Black action camera mounted on an inexpensive "Orbit" two-hour mechanical hose watering timer. The camera was set for "Video" mode / "Time Lapse Video" submode at a resolution of 4K and an interval of two (2) seconds. Approximately 26 minutes of actual recording time resulted in 26 seconds of "raw" time lapse video, given the recording settings I use.

27 February 2026.

"Sky Condition" - cloud amount and height

The following graphic shows an excerpt from the table of three-day weather observations for KDCA on 27 February 2026 nearest the time when I recorded the time lapse video (shown above). The columns labeled "Weather" and "Sky Cond." are highlighted by a red rectangle.

Source Credit: KDCA | National Weather Service.

On 27 February, the "Sky Condition" was reported as "FEW030" and "FEW040" for the two times shown in the table of observations for KDCA, meaning the cloud amount was "FEW" (1/8 to 2/8 of sky coverage) and the cloud height was "3,000" to "4,000" feet. These low level clouds are fair weather cumulus (Cu).

A well defined aircraft condensation trail (contrail) is also visible beginning at the 18 s mark and continuing until near the end of the video. The contrail is much higher than the cumulus clouds.

Average air pressure at sea level is 1013.25 millibars (hPa), or 29.92 inches of mercury (inHg). Cloud formation was suppressed by the relatively high air pressures of 1019.0 and 1018.4 millibars observed at KDCA on 27 February 2026. Hence the mostly clear skies at the time I recorded my video.

Tech Tips

Notice the "lens flare" that appears from the 26 second mark to the end of video. This was caused as the camera rotated counterclockwise toward the Sun in the sky. Please comment on this blog post if you can suggest how to avoid lens flare.

The Backstory

You might be wondering why I went to the roof to capture a SkyLapse© on a nearly cloudless day. Well, I was so eager to field test a new configuration of my "Orbit" panoramic rig that I decided to go despite a less than interesting cloudscape. When I got outside I realized the field test would be a waste of time so I reconfigured the rig slightly and shot a simpler panoramic time lapse than the one I had planned. What was I planning? That will be the subject of a future blog post, to be published whenever the sky cooperates. Please stay tuned.

Related Resources 

• Cloud identification - a blog post by Walter Sanford
• Clockwise "Orbit" - another blog post by Walter Sanford
• Post update: Minor modifications of "Orbit" panoramic time lapse rig - yet another blog post by Walter Sanford

Copyright © 2026 by Walter Sanford. All rights reserved.

More "Skyflow" testing

Three time lapse video segments were captured and created using "Skyflow," an Apple iOS app running on my Apple iPad mini 6. The first video clip was created from 427 frames (~14 s), the second clip from 151 frames (~5 s), and the third clip from 433 frames (~14 s). Each video clip was edited individually using Apple "Photos" and all three video clips were combined using Apple "iMovie."

Each video segment shows mostly high level cirroform clouds moving across the sky over Fairfax County, Virginia USA during the afternoon of 17 February 2026.

17 February 2026.

I feel like the lack of complete documentation for the app is preventing me from getting the best results possible. I've figured out how to use many of the major features, although I'm still not sure how to use the controls for focus and exposure most effectively. A few questions follow. Please comment on this blog post if you can answer any of my questions.

1. When shooting a "SkyLapse ©" from a fixed position, should I expose for the highlights (e.g., bright, white clouds) and lock exposure? [Drag circle (the custom exposure point) over clouds and tap AE-L?]
2. When shooting a panoramic "SkyLapse ©" should I use continuous auto focus (AF), auto exposure (AE), and auto white balance (AW)?
3. Using the in-app editor, trimming video is a destructive edit [personal communication with developer]. Is cropping a destructive or non-destructive edit? And what about speed ramping (either up or down)?
4. What is the recommended workflow for in-app editing of RAW files (negatives/DNGs)?
5. Can "Skyflow" be used with external storage devices such as a USB memory stick or SSD? Backup, of course, but what about about deleting projects (to save disc space on my iOS device) and restoring them later for more editing?

Camera (iOS app) > "Pano" mode

Before working with "Skyflow," the following panoramic composite image was taken using the "Camera" app on my Apple iPad mini 6, set for "Pano" mode. The camera panned ~270° from west-northwest to south-southeast.

17 February 2026. Wider panoramic view. (14913 x 3694 pixels)

Have I mentioned how much I like the look and feel of the panoramic composite images created using the "Camera" app? I do. Easy to use. Excellent output. Good job by you, Apple!

Related Resources

• "Skyflow" app (first field test) - a blog post by Walter Sanford
• Skyflow - Apple iOS app for creating time lapse videos, by Andrei Kovalev
• Best iPhone TIMELAPSE app (3:59) - a YouTube video by Matthew Vandeputte
• Skyflow (Time Lapse App) Walk-Through Tutorial for Beginners (6:49) - a YouTube video by "Cloudage"

Copyright © 2026 by Walter Sanford. All rights reserved.

Clockwise "Orbit"

The following panoramic time lapse video shows the sky over Fairfax County, Virginia USA during the afternoon of 17 February 2026. A variety of mostly high level cirroform clouds can be seen moving across the sky.

The video was recorded using my GoPro HERO4 Black action camera mounted on an inexpensive "Orbit" two-hour mechanical hose watering timer. The camera was set for "Video" mode / "Time Lapse Video" submode at a resolution of 4K and an interval of two (2) seconds. Approximately 46 minutes of actual recording time resulted in 46 seconds of "raw" time lapse video, given the recording settings I use.

17 February 2026. Panoramic view from north to south.

The rig was turned upside-down so the action camera would rotate clockwise (rather than counterclockwise), as shown in the following photo.

Clockwise "Orbit" rig.

Notice the homemade safety strap used to tether the action camera to the tripod. Better safe than sorry, right? There is enough slack in the strap so the camera can rotate freely. For more information about my safety strap, see the "Tech Tips" section in one of my earlier blog posts entitled "Atmospheric Motion."

Tech Tips

Set your GoPro action camera so the image is automatically right-side-up even when the camera is upside-down. Go to Settings/Camera Preferences/Setup. Set the camera for "Auto Rotation." [There are three options: Up; Down; and Auto.]

GoPro Quik | Camera Preferences for GoPro HERO4 Black.

I don't worry about setting the "Orbit" timer for a specific amount of time. I just turn the dial clockwise until it's set for two hours. Then I compose the shot and start recording for as long as I need/want.

Related Resources

• Panoramic time lapse rig using "Orbit" two-hour mechanical hose watering timer - a blog post by Walter Sanford
• First field test: "Orbit" panoramic time lapse timer - another blog post by Walter Sanford
• Post update: Minor modifications of "Orbit" panoramic time lapse rig - another blog post by Walter Sanford

Copyright © 2026 by Walter Sanford. All rights reserved.

Cloud identification

The following time lapse video was captured and created using "Skyflow," an Apple iOS app running on my Apple iPad mini 6. The video (~5 seconds long) was created from 151 frames stored in the "Files" app (Files/On My iPad/Skyflow/Projects). The photos were recorded from ~2:09 p.m. (14:09) to ~2:14 p.m. (14:14) using a two-second interval; each photo is 1.4 MB.

The video shows the sky over Fairfax County, Virginia USA during the afternoon of 17 February 2026. Can you identify the small, white puffy cottonball-like clouds shown in the video?

17 February 2026. Facing south-southwest.

Levels

Begin by trying to determine the "level" of the clouds. According to the International Cloud Atlas, there are three levels of clouds in the atmosphere (as shown in the following table): high; middle; and low. [Note: "Clouds with vertical development" is a fourth level used by some experts.] Since my home is located in the northern mid-latitudes, the column labeled "Temperate region" is highlighted by a red rectangle.

Source Credit: Levels | International Cloud Atlas.

"Sky Condition" - cloud amount and height

OK, let's assume you think the level of the clouds shown in the video is "High." Is there information available to confirm your inference?

When the height of a particular cloud is known, the concept of levels may be of some help to the observer in identifying the cloud. Source Credit: Levels | International Cloud Atlas.

Weather observations, sometimes automated, are available online (updated every hour) for select locations (often major airports) in the United States of America. For example Weather observations for the past three days for Washington/Reagan National Airport, DC is available for KDCA, the airport nearest my home. The following graphic shows the weather observations for KDCA on 17 February 2026 nearest the times when I recorded the time lapse video (shown above). The column labeled "Sky Cond." is highlighted by a red rectangle.

Source Credit: KDCA | National Weather Service.

"Sky Condition" is reported for cloud amount and height.

Sky condition shall be coded in the format XXXYYY where XXX is the cloud amount code (e.g. FEW or BKN) and YYY its height above surface using 3 figures. Source Credit: METAR explanation.

The following table shows the codes used to estimate the cloud amount.

Source Credit: METAR explanation.

On 17 February, the "Sky Condition" is reported as "BKN210" for both times shown in the excerpt from the table of three-day observations for KDCA, meaning the cloud amount was "Broken" (5/8 to 7/8 of sky coverage) and the cloud height was "21,000" feet. At a height of 21,000 feet the cloud level is "High," meaning your inference is correct.

Now ask yourself, which High cloud "Genera" most closely matches the clouds shown in the video — Cirrus, Cirrocumulus, or Cirrostratus? That's right, the small, white puffy cottonball-like clouds shown in the video are Cirrocumulus clouds (Cc).

Tech Tips

How can you find near-real-time weather observations for your location? Use a table of three-letter LOCIDs (location identifiers) to find the nearest airport. For example, LAX is one of the airports near Los Angeles, California USA. Add the letter "K" in front of LAX and you get "KLAX." Take the Web address I provided for KDCA and change it as follows ...

https://forecast.weather.gov/data/obhistory/KLAX.html

This URL will take you to Weather observations for the past three days for Los Angeles, Los Angeles International Airport. The table is dynamic, meaning it is updated automatically every hour. (You might need to reload the page in order to get the latest observations.)

Deja vu

Did you notice the jet airplane that's visible in the last six frames of the video, moving from right to left across the screen beginning near the middle-right edge of the frame? That reminds me of "Sub-sensory imagery," a blog post I published in early January 2026.

My good friend Luis Acosta commented on aircraft condensation trails (contrails) that are also visible in the video. The contrails are probably higher than the cirrocumulus clouds.

Related Resources

• Weather observations for the past three days for Washington/Reagan National Airport, DC | NOAA NWS
• Weather observations for the past three days for Washington/Dulles International Airport, DC | NOAA NWS
• METAR explanation | IVAO Documentation Library - see section entitled "Cloud layers/Cloud amount and height"
• United States Airport Codes : Three Letter US Airport Codes [third party resource]
• Weather instruments at KDCA - Google Search
• National Weather Service Glossary
• Ten Basic Clouds | National Oceanic and Atmospheric Administration
• Introduction to Clouds / Sky Watcher Chart | NOAA NASA [PDF]
• Cloud Types | Center for Science Education | UCAR
• Module 4 - Cloud Identification | UW-Madison

Copyright © 2026 by Walter Sanford. All rights reserved.

How to animate weather satellite imagery using "Gallery" (Android)

The AMS interactive infrared [weather] satellite image that works with a variety of devices in the Apple ecosystem also works with my Samsung Galaxy Tab A9+ (Android OS).

Black pixel = 20.5℃ (68.9℉).

Gray pixel = 10.0℃ (50℉).

White pixel = -45.0℃ (-49℉).

Create an animated GIF

"Gallery" is a native application in Samsung Android OS that can be used to animate the non-interactive infrared images, thereby creating a time lapse "video" of the Earth as seen from space. Animations enable the viewer to determine the direction and speed weather systems are moving.

Follow these simple directions to create an animated GIF using the "Gallery" app.

1. Open"Gallery."
2. Select several images.
3. Select "Create" and choose "GIF."
4. Tap the "Direction and speed" icon; change the direction for playback (if necessary) and adjust Speed as necessary.
5. Tap the "Save" button.

As always, the devil is in the details but the preceding directions should get you started. In my case, I had to change the direction for playback by tapping the clock icon, then tapping the back arrow (←). For more information watch the two YouTube videos by "Samsung Care," listed under "Related Resources" (at the end of this blog post).

A 12-hour time series of non-interactive images was used to create the following animated GIFs (with a one-hour interval between images). Notice the warm air advection moving from south-southwest to north-northeast across the southeastern United States of America. Also notice midday heating causes Mexico to "bloom" in dark gray-to-black pixels, indicating very warm land temperatures.

Animation created using "Gallery." Speed = 3 (default).

Animation created using "Gallery." Speed = 4.

Animation created using "Gallery." Speed = 5.

Animation created using "Gallery." Speed = 6.

Which animation speed do you prefer -- 3, 4, 5, or 6?

For comparison, "GIFfun" (Apple Mac OS) was used to create the last animation from the same 12-hour times series of images as the "Gallery" (Android OS) animations. As you can see, the results are similar for both applications.

Animation created using "GIFfun." Delay Time = 0.2 s.

Related Resources

• Create a GIF in your Galaxy phone using photos from the Gallery app | Samsung US (2:07) by Samsung Care
• Different ways to create GIFs on your Galaxy phone | Samsung US (3:30) by Samsung Care
• UTC/EST/EDT – a table listing equivalent times among Universal Time Coordinated (UTC), Eastern Standard Time (EST), and Eastern Daylight Time (EDT), rescued from the Wayback Machine Internet Archive
• Weather Calculators, including temperature conversion – a page of interactive calculators that still work, also rescued from the Wayback Machine Internet Archive
• How to animate weather satellite imagery using "GIFfun" (MacOS) - a blog post by Walter Sanford

Copyright © 2026 by Walter Sanford. All rights reserved.

How to animate weather satellite imagery using "GIFfun" (MacOS)

The AMS interactive infrared [weather] satellite image resulted from the collaboration between the American Meteorological Society (AMS) education initiatives and the Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison.

Infrared imagery is one of three types of weather satellite imagery (including visible, infrared, and water vapor). Black, white, and shades of gray are used to represent temperatures from the tops of clouds and the land & water surfaces on Earth. Black is the hottest temperature; white is the coldest.

Red crosshairs highlights black to gray to white pixels.

A brief description of the interactive image says (incorrectly) "The images are created every three hours ..." — the images are actually updated every hour. Times are expressed in Universal Time Coordinated (UTC).

Have fun exploring the interactive infrared image. Then you might want to try animating a time series of non-interactive images.

Tech Tips

The interactive infrared [weather] satellite image was tested using my Apple iPad mini 2 and 6, Apple MacBook Air (13″, M1, 2020), and Apple iMac desktop computer (vintage 2009) and is compatible with all of those devices. Post update: The interactive IR satellite image also works with my Samsung Galaxy Tab A9+ (Android OS).

Did you notice both the non-interactive and interactive infrared images are GIF files? "GIFfun" is a free application for Apple MacOS that can be used to animate the non-interactive infrared images, thereby creating a time lapse "video" of the Earth as seen from space. Animations enable the viewer to determine the direction and speed weather systems are moving.

A 10-hour time series of non-interactive images was used to create the following animated GIFs (with a one-hour interval between images). Notice the large scale mid-latitude wave cyclone moving from west to east across the central United States of America.

The default "Delay Time" ("the display time for each frame, in seconds") is 0.1 s, resulting in a faster version of the animation.

Faster version.

Slower version.

The following screenshot shows the settings for "GIFfun" that were used to create the slower version of the animation, shown above. Notice the "Delay Time" was doubled from 0.1 s to 0.2 s.

"GIFfun" settings for slower version.

Which version looks better? You decide.

Related Resources

• AMS interactive infrared [weather] satellite image – the American Meteorological Society (AMS) and the Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison
• AMS Weather Satellites Teacher's Guide [PDF]
• Interactive infrared weather satellite image - a blog post by Walter Sanford
• AMS Interactive Infrared Weather Satellite Image – Making the Invisible Visible. A resource rescued from the Wayback Machine Internet Archive. I created this activity as an extra credit opportunity for my Grade 8 Physical Science students when we were studying energy and energy transformations. In retrospect the activity is probably too long to use “as is,” but it might serve as a data bank of questions that teachers could use to create their own version of the activity. For non-educators, the activity questions can help to guide your thinking about what you can tell from the interactive infrared imagery.
• UTC/EST/EDT – a table listing equivalent times among Universal Time Coordinated (UTC), Eastern Standard Time (EST), and Eastern Daylight Time (EDT), rescued from the Wayback Machine Internet Archive
• Weather Calculators, including temperature conversion – a page of interactive calculators that still work, also rescued from the Wayback Machine Internet Archive

Copyright © 2026 by Walter Sanford. All rights reserved.