Exposure and Tracking for a Total Solar Eclipse

They say you should use the full moon to get your initial exposure settings for the totality phase of a solar eclipse. I guess the settings for my setup will be like the ones I used on this picture from last night.

1/100s and 100 ISO
Nikon D7100 on the back of a Celestron 90GT 910mm Telescope

The video tests were similar. I liked 1080p30, 1/125s, and 100 ISO.

We’ve been having a lot of rain, clouds, and haze lately. Last night was my best night for the full moon trials. Today, I moved on with the sun trials.

1/125s at ISO 100
Nikon D7100 on the back of a Celestron 90GT 910mm Telescope
Thousand Oaks Optical Silver-Black Polymer Filter

Wow. How boring is this? One teeny sunspot? Hmm.. I’m not getting great focus today. Moist atmosphere I think. I did get rid of the light leak by covering the viewfinder. The contrast is great! I also worked to shield the monitor so I could focus without glare in the daylight.

Getting things in focus. Well, technically, I’m centering.

My son took that one. There’s an HDMI port on the camera. I ran it to a 24″ monitor and put that in a box with a black cloth hood. Works for my old eyes.

The monitor in the box

There’s a reticle taped to the frame of the monitor. It helps me keep the sun/moon image centered when there is drift in the tracking. When I see error, I can adjust with the slewing controls on the telescope. The image is a composite of several reticle types I found on the internet. I wanted concentric circles, a cross in the center and a ring with degrees for noting the position of sunspots. I used a similar reticle for the July 11, 1991 eclipse.

Closeup of the reticle. Remember making overhead projector transparencies for presentations? That was before PowerPoint and cheap video projectors. This is pretty much one of those. Who still has the plastic? I didn’t. 5 sheets for $6 on Amazon! This time I used my inkjet printer to add the text and lines. Last time I copied the reticle from a book onto the transparency sheet using the copier at work.

3 thoughts on “Exposure and Tracking for a Total Solar Eclipse

  1. I thought I had this posted yesterday, but this morning I just found a corrupted rough draft in the drafts folder, and there was no sign of the post in the published posts. Maybe It was because I had the post open for editing on two different computers. I think I just saw another draft disappear too. Weird.


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