RichKenn Loc: Merritt Island, FL

Someone asked not long ago something like, "How quickly does a rocket take off...?" Some responded, "Quickly." I didn't think so. I decided to see if I could quantify my feeling. So, I took a series of pictures of a recent SpaceX flight and looked at the times. I cropped the pictures considerably and pasted them together. Then I took a picture of the clock on my computer to calibrate the camera's clock. From the time the fire was lit until it rose half its length was 40 seconds! But, a few seconds later it traveled its length in one second. FYI, I shot with a D7200 with a Sigma 150-500 mm lens at 450 mm. The launch site is 17 miles away so haze is an added problem. It takes a minute and a half for the sound to reach me. Us old guys have to have some fun.

Kaboom!

(Download)

Longshadow Loc: Audubon, PA, United States

UTMike Loc: South Jordan, UT

Good idea, well executed, Rich!

RichKenn Loc: Merritt Island, FL

Thanks, guys.

User ID

All four feet of the ground at once !

RichKenn Loc: Merritt Island, FL

Huh?

DIRTY HARRY Loc: Hartland, Michigan

It depends on the size and purpose of the rocket. A anti-aircraft/ missile rocket has a much highr thrust to weight ratio and accelerates much faster.

Earnest Botello Loc: Hockley, Texas

Very well done, Rich.

RichKenn Loc: Merritt Island, FL

I am sure you are right. Thank goodness I have never seen an antimissile firing.

neillaubenthal

An excellent composite…but something is off with your time scale. I just looked at the replay of the GPS Falcon 9 launch the other day…right at T0 the engines lit..cleared the tower at T+6 seconds and was at 3KM altitude or about 10,000 or 11,000 feet at T+40 seconds. Hard to tell where the disconnect is but if you take a look at the EXIF data in Lightroom or whatever that will give you the time for each exposure.

Earlier reply on type of rocket is right. My submarine launched a SUBROC missile which goes horizontally out of the torpedo tube, ignites under water and Nike’s up to bout a 40 degree angle. Through the scope I could not really see the missile leave the water, just a very brief flash and smoke trail receding quickly. The ballistic missiles that a missile sub carries don’t ignite until out of the water and have 8 to 10 Gs of acceleration…so 1 second after ignition they are already going about 160 feet per second or about 110 mph and are about 2 or 3 missile lengths of about 30 feet high. The videos you’ve likely seen on TV or YouTube of them are considerably slowed down. Manned launches only leave the pad at 2 Gs or so to keep the crew from blacking out and max out at maybe 3.5 per so just before engine cutoff at orbital velocity.

PhotogHobbyist Loc: Bradford, PA

As neillaubenthal mentioned, the EXIF data of the photos would provide the time of the photos for determining the time needed for liftoff. Also with passengers onboard the G-force has to be controlled to prevent black-out of the astronauts. However, as Dirty Harry wrote, the thrust of the rockets may vary depending on the size, purpose and payload of the rocket.

joecichjr Loc: Chicago S. Suburbs, Illinois, USA

A cool, enlightening experiment 🏆✳️🏆

RichKenn Loc: Merritt Island, FL

The times listed on the photos are from the EXIF data. My camera clock is off so I took a picture of the clock on my computer and corrected each reading so I believe the quoted times are correct. The first time is just at ignition and that was the predicted time of launch. Catching the first glimmer of ignition was serendipitous.