Sunday, October 9, 2016

Following Observe the Moon Night with (Carefully) Observe the SUNday

Can the Sunday after International Observe the Moon Night be known as Carefully Observe the Sun Day? Maybe we shouldn't encourage the general public to observe the sun, that could turn bad. But anyway, I had gorgeous clear skies today and had a busy and fun morning working on solar projects! I don't observe the sun all that often. Check it out, each of the active regions (sunspots) are the size of the Earth!

sunspots october 9 2016
Canon T5i single frame prime focus on Meade 285, ISO 800, 1/60 sec, 900mm

I find it much more challenging than observing the moon for a few reasons: You can't look at the sun to line up your telescope - I ended up slewing around hoping to stumble upon it in my eyepiece. Viewing your camera's LCD screen in the daytime is terrible - and if you rely on it to focus like I do, this becomes extremely challenging.

Today's sun from sohowww.nascom.nasa.gov showing active regions

I modified my homemade DSLR solar filter to fit over my telescope. This is my first solar image at prime focus, and it was my first time observing the sun through my telescope eyepiece. Here are some more photos from today:

meade 285 refractor solar observing
My solar observing setup with Canon T5i at prime focus on Meade 285 with homemade solar filter

I noticed the finder scope was producing a scary looking magnified dot of light, and I imagined a magnifying glass burning a hole in my shirt while I looked through the telescope. No thanks! While it didn't look like the dot was too hot, I covered the finder scope with an eyepiece cap just to be safe.

finder scope and sunlightcover finder scope


Here is my homemade solar filter attached to the telescope. The tube is a good fit, but I added some tape just to make sure it wouldn't blow off while I had my camera attached to it. I'll go into more detail about the modification to my filter in a separate post.

meade 285 refractor solar observing
DIY solar filter anchored with tape so it doesn't blow off and ruin my camera or blind me in one eye. 
There's a trade off between the resolution of the sun at prime focus, and the ability to carefully control focus with the Canon T5i focus controlled by my laptop. So what's more important? A larger disk size but clunky manual focus out in the sunlight where it's hard to see anyway? Or careful laptop focus controls but smaller disk of the sun?

camera hooked up to computer
Canon T5i with 300mm lens and solar filter connected to my laptop with EOS Utility
sun 300mm
Canon T5i 3 frames stacked in Registax, ISO 400, 300mm, f/9, 1/250 sec
I think the resolution wins and the prime focus is a little nicer even though it's not as sharp, it looks more natural even in one frame without stacking. What do you think?

compare prime vs 300mm sun photo
Compare prime focus sun (left) vs DSLR at 300mm stacked (right) 

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