Photographing Saturday's SpaceX launch Question

Started 3 months ago | Discussions thread
Mark Scott Abeln
Mark Scott Abeln Forum Pro • Posts: 16,420
A quick estimate

red sled wrote:

Planning to be in Titusville for this Saturday's SpaceX launch. I'll have my D500 and Nikon AF-S 500 f/4 VR lens and TC-20EIII. Can anyone suggest whether at this distance I should have the TC installed or just use the 500 f/4 without the teleconverter ? I wish I'd had this equipment when we watched the final launch of the Space Shuttle Columbia.

Do you know precisely the launch site and where you will be shooting from? If so, you can use Google Maps to determine how far away you'll be. If you are using the desktop Google Maps website, you can right click on an object and measure a direct distance from another place.

Do you know how tall is the SpaceX vehicle?

We know that your sensor size is 15.7 mm x 23.5 mm and that your focal length is either 500 mm or 1000 mm with the teleconverter.

Simple geometry, the law of similar triangles, suffices for this, and so we get this equality:

Height of rocket / Distance to rocket = Size of image / focal length

Let's assume that the Falcon 9 is 229.6 feet tall and the distance from Space View Park in Titusville to Launch Complex 39A is 12 miles away, or since there are 5280 feet per mile, that would make it about 63,360 feet. I have no idea if these values are correct, but these are just quick values gotten off the Internet. But this isn't rocket science, and so perfect accuracy isn't really needed.

So we have:

229.6 feet / 63,360 feet = Size of image / focal length, or

Size of image = focal length x 229.6 feet / 63,360 feet

For 500 mm we get a 1.8 mm image height and for 1000 mm we get 3.6 mm. Your sensor is 15.7 mm high on the short dimension, and so the rocket will cover about 11.5% of the sensor height at 500 mm and about 23% with the 1000 mm.

Whichever one you choose will depend at least partly on how well you can track a moving object. I'd definitely use the teleconverter to get shots of the rocket on the launchpad.

Good luck and share any good results with us!

 Mark Scott Abeln's gear list:Mark Scott Abeln's gear list
Nikon D200 Nikon D7000 Nikon D750 Nikon AF-S DX Nikkor 35mm F1.8G Nikon AF Nikkor 50mm f/1.8D +3 more
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