Tag Archives: astrophotography

A quick way to understand the basic steps in smartphone astrophotography

PolyWogg.ca
August 10 2018

I’ve posted a few times about my experience with smartphone astrophotography. A person who is active online in this area, Kevin Francis, shared with me a copy of an infographic he did based on his experiences.

You can find the infographic over at:

http://kevinrfrancis.com/2018/07/smartphone-astrophotography-6-steps/

Note that the infographic isn`t meant to give you all the details, but I like his framing:

  1. Choosing your equipment (i.e., pick a smartphone);
  2. Choose a camera app (there are only really two great ones, depends on which OS you`re running);
  3. Use a tripod or mount to make it steady;
  4. Decide if you`re using the phone by itself, marrying it to a lens, or shooting through a telescope;
  5. Capture the image (single shots, long or short exposures, multiple images for stacking, etc.);
  6. Process the images you took.

Is that level of detail going to get you going today? No, but it will tell you the basics you need to know so you can start thinking about what you want to do. Thanks to Kevin for sharing…

Articles I Like: 600 Rule?

PolyWogg.ca
May 16 2018

There is a rule that photographers use to figure out how long of an exposure you can do on a camera before you’ll start to see star trails. This assumes, of course, that you’re not TRYING to get star trails. Instead, you want those lovely little pinpoint stars. The classic rule says you take a set number of 600 and divide it by the effective focal length of the camera lens. If you have a nifty 50 lens, that means you would be able to do about 12 seconds of exposure before streaking occurs.

Most astronomers feel that the 600 number is a little high. More like 500. So then you would say 10 seconds. There’s a small extra factor in there if it is a crop sensor instead of a full-frame, and so for most DSLRs, you have to divide further by 1.6. So the article attached calculates that down to 7.5 seconds.

Perfectly logical, simple math. But as the article points out, that’s not entirely true. The premise is solid though, if you think about it. Let’s say you used one of those big honking 500mm lenses and the rule 500, ignoring the crop sensor. It would say that if you’re going to point it at a small section of the sky, you are so “zoomed in”, that you’re going to see streaks for anything over a 1s exposure.… Read the rest

Bad astro alignment if I don’t listen to myself

PolyWogg.ca
May 11 2018

So I posted earlier that my astronomy season has kicked off, and I’m good to go. With the news that Jupiter was in opposition this week (the closest it will come to Earth all year, hence LOOK NOW for your best view), I thought, “Well, yeah, I want to set up”. And because it’s a PLANET, not some dark sky object, I can do it from my backyard.

So on Tuesday, I was in a hurry to set up before Venus disappeared behind a house, and I wanted to show my wife and son, so I set up the scope on our deck. Anyone who knows scopes knows a deck is a bad idea unless it’s cement. Otherwise, they jiggle if anyone walks. Hard to get vibrations out, but whatever. Anyway, got it set up, quick solar system alignment on Venus, good to go, showed the family, all good.

Then I did a quick sky tour, realigned on Procyon and Capella, not bad, and then I started doing a quick sky tour while I waited for Jupiter to come up over a house. Not awesome, but then again, I hadn’t done ANY OF THE PROPER ALIGNMENT THINGS I know I need to do.… Read the rest

Articles I Like: How to Take Good Photos of the Moon

PolyWogg.ca
November 11 2017

I’m frequently on the lookout for tips and tricks for astrophotography, although my ambitions are a bit basic to start with — smartphone use at the telescope eyepiece for now, maybe graduating to DSLR and webcam stuff later. And some of the easiest of the early photos are for moon shots. So, of course, I clicked when I saw an article on HowToGeeek.com entitled How to Take Good Photos of the Moon (by Harry Guinness, September 13th, 2017).

He breaks the challenge down pretty succinctly: the brightness and the distance. On the technical side, he recommends a tripod (duh), plus a 200mm lens for full-frame and 130mm on a crop-sensor. The tip, and why I thought the article was useful, came with a rule I’ve never heard of — Looney 11.

Astrophotographers have a rule for taking photos of the moon (it’s more of a guideline really) called Looney 11. The idea is that if you set your aperture to f/11, the correct shutter speed will be the reciprocal of the ISO. In other words, if your aperture is set to f/11 and your ISO is set to 100, your shutter speed will be 1/100; if your ISO is 400, the shutter speed is 1/400.

… Read the rest