Camera Equipment

[Charlie in Dayton]

The latest installment of my occasional series of tech articles on new stuff I run across is posted here for your edification.

 

[Soapy Sam]

Charlie- I work on rigs. In March 06 I have a chance to be offshore in the north Caspian sea during a total eclipse. Right now, all cameras are banned on the rig, but I hope to get around that.

I have an Olympus OM2, unused for 4 years (ulp!) since I got my first Fuji digital, a Finepix 4700. That developed a fault recently and was replaced with a Fuji F810 zoom. This is a pocket camera. Given that we might / might not get permission for cameras, but that space restrictions will probably limit me to the F810, what's the best use I could make of it on the day?
Any useful suggestions welcomed.

 

[Charlie in Dayton]

Charlie- I work on rigs. In March 06 I have a chance to be offshore in the north Caspian sea during a total eclipse. Right now, all cameras are banned on the rig, but I hope to get around that.

I have an Olympus OM2, unused for 4 years (ulp!) since I got my first Fuji digital, a Finepix 4700. That developed a fault recently and was replaced with a Fuji F810 zoom. This is a pocket camera. Given that we might / might not get permission for cameras, but that space restrictions will probably limit me to the F810, what's the best use I could make of it on the day?
Any useful suggestions welcomed.

First off, congratulations on being in a place to see a total eclipse -- those opportunities don't come often. Here's hoping you get to experience the ultimate -- being in the path of totality! There's a very nice page chock full of interesting info on this at NASA's Eclipse Home Page.

Okay, so you've got a camera, and you want to take pitchers of the eclipse...these are in no particular order, I'll leave that part up to you.

Get the camera out NOW and make sure it's in tip-top operating condition. Follow the manufacturer's recommendations for cleaning the lenses. Practice with the camera NOW so you know where everything is and how to use it blindfolded.

Get the biggest memory card the camera will hold. Get two. Make sure they both work.

When you leave for the eclipse observing site, make sure you've got both memory cards, a fresh set of batteries in the camera, a spare fresh set of batteries in one pocket, and the camera's instruction manual in the other.

Sign up TODAY over at The All-New And Improved Bad Astronomy and Universe Today Forum, and pay specific attention to the Astrophotography and Astronomical Observing, Equipment, and Accessories forums. Ask numerous questions -- I guarantee that if you act as if you have more than three consecutive brain cells, you'll be treated with respect and you'll have your questions answered in much greater detail than I can -- I'm still a beginner at this, and the guys over there have forgotten more than I know...

This part cannot be stressed too highly -- FAILURE TO FOLLOW PROPER SAFETY PROCEDURES FOR VIEWING THE SUN WILL RESULT IN PHYSICAL INJURIES UP TO AND INCLUDING IMMEDIATE PERMANENT LOSS OF SIGHT!! So, don't take chances. The safety precautions mentioned here and on websites referred to here are simple, but they are vital!

Here's a short version of something I did awhile back on homemade solar filters.

There are two popular sources for homemade solar filter material. Baader AstroSolar™ material is available from Astro-Physics. It's a silver mylar-style film material. Thousand Oaks Black Polymer is available from Thousand Oaks Optical, and is a black plastic film-appearing material.

How easy are they to work with? Very simple. I've made filters for all my various oculars, working with nothing more exotic than cardboard, construction paper, binder clips, and double-sided tape.

The filters are easily constructed if you follow the instructions.

The monoculars are little items I've carried around for ages that are unfortunately no longer carried by the original source. They may be found on ebay. They're 8x21 monocular refractors (if you get lucky, you might find the one with two objectives, giving you a 6x21 power also). The objective lens shells are about 1" across, making it easy to build a filter. There's a cylinder of construction paper inside and outside the pie-wedge cutouts in a piece of cardboard, that slips over the end of the lens. Two thin 2" square pieces of cardboard (like shirt cardboard) have holes cut just a bit less than the lens diameter, so that the lens shell will not touch the filter material. The filter material is secured between the cardboard pieces, and the pieces are taped together. They are clipped to the piece that slips tightly over the lens. Depending on my preference of the day, I can swap filter material in seconds. It may not seem like it, but magnifications/apertures as low as 6x21mm and 8x21mm are more than enough to see sunspots. The filters will fit the monocular shown in my camera lens analysis, and I'm planning on doing a little experimentation with solar photography with that camera, lens, monocular, and filter combination.

With only small variations in technique, and scaling things up for size, I have used the same basic technique to build Baader AstroSolar and Thousand Oaks filters for my 10x50 binoculars, and my 3" and 4.5" reflecting telescopes. They work just fine.

Now, what's the difference between the filter materials? Let's start with color. I took my garden variety drug store 35mm camera and took a picture of the sun by holding each filter in front of the lens. When I got the film developed, I scanned the pics at max resolution and cropped them so that only the Sun was visible, then blew the pictures up in Photoshop so the solar image was a decent visible size. There were absolutely no color adjustments made to the pictures.

As you can see, there is a definite difference. The Baader material is on the left, and gives a whiter more intense image. The Thousand Oaks is on the right, and is more yellow and a bit easier on the eye in this writer's opinion. Sunspots were plainly visible equally well through both filters.This is a case of personal preference, which one gives the more pleasing view. Neither one has the capability to show prominences, so don't expect these to perform like H-alpha filters...just ain't gonna happen. In my opinion, while neither filter is as rugged as your standard double-wall lawn'n'leaf bag, the Thousand Oaks material does seem to be a bit more stout. Check each manufacturer's website for respective handling cautions and material guarantees.
I've checked with both manufacturers -- both make a version that's safe for photography but not for eyeball use. The denser visual materials (they cut the visible light down to 1 part in 100,000) are suitable for photography also if appropriate allowances are made in exposure times.

Again, I cannot stress too highly to follow all the safety precautions on the solar filter material websites.

What does this have to do with you? Hey, your camera, a tripod, and a homemade solar filter to fit your camera -- go out and get some practice beforehand...exposures, zoom levels, things like that...I'll bet you will amaze yourself just how nice your solar pictures can be...