Viewing with Two Eyes

When I was doing some solar observing last week, I was having some problems keeping my single eye focused and open while also keeping my other eye closed.  After about five or ten minutes of observing with one eye, my eyes were twitching and they simply were not cooperating anymore.  I am definitely getting old!  

These types of eye difficulties are often related to typical weakness due to old age but it is also partially related to my primary illness.  If I am beginning to have difficulty seeing through my telescopes as I did the other day, then that is a serious problem and I need to find a solution to this problem.  

I felt the best solution was to get a binoviewer made specifically for telescopes so I could view the sky with both eyes instead of only one.  This is known to alleviate the typical eye strain from viewing with only one eye for longer periods of time.

So, a couple of days ago, I ordered a binoviewer to be used on my telescopes and it arrived in the mail today.  Naturally, I had to give them a whirl no matter what the weather was like.  If it was raining or overcast, I figured I would have tested them by viewing distant trees.  If the sky was unusually clear, I would have to give them a whirl by viewing something in the sky.  By a stroke of very unusual luck, the sky was clear this evening so this provided me with an opportunity to see how well this new binoviewer works on two of my telescopes.

A binoviewer converts the typical single eyepiece of a traditional telescope to having two eyepieces in a binocular head connected to the telescope where you would normally insert a lone eyepiece.  I already have a binocular head for my microscope and I know I prefer viewing with the microscope with two eyes rather than one.  I was looking forward to trying this for astronomy too.

In the photo, above, you can see the two eyepieces on the back end of my telescope.  These two eyepieces are inserted into the binoviewer.  That bright blob in the shape of a crescent up in the sky is the moon.  Down a bit from the moon toward the tallest tree, is Mars (which wasn't visible yet when I shot this quick snapshot).  And, to the right a little bit out of the frame and quickly nearing the treetops was Venus.  In this particular photo, I like how the moon is reflecting off the dew shield on the front end of my telescope.  

The binoviewer arrived in the mail today.  Sheila and I were busy all day (with another hospital visit which I'll write more about in another blog entry) but after dinner, at around 8pm, I started moving some astronomy gear outside.  I knew the moon was up in the sky.  It was still light outside and it was the blue hour when the sky appears a deep blue as it darkens but I knew it was still easy to view the moon.  I also knew that as the sky darkened, it would be easy to spot Mars and Venus which were located near the moon on this evening.  

The views through this new binoviewer were spectacular and very easy on the eyes!  As the sky darkened, I first spotted very bright Venus and observed that for a little while.  Before long, I was able to spot the much fainter Mars and observed that for a short while.  The views were great and I had no eye strain nor any eye twitching at all.  The views were crisp and contrasty which is exactly what you want through good optics.  

In this photo, above, it is easy to see the silhouette of the binoviewer with the two eyepieces.  Just like in the top photo, I like the way the moon is reflecting off the front dew shield of the telescope.  These are the William Optics Binoviewer that comes with two 20mm eyepieces as well as a 1.6x corrector lens.  The corrector lens helps to get some telescopes come to focus while using the binoviewer.  In my case on this particular evening, I needed to use the 1.6x corrector lens.  

Getting the spacing correct when you add a binoviewer can be troublesome.  If you are lucky, you have the extra room to add the binoviewer and everything is just fine.  This wasn't my situation.  For me, the binoviewers ate up too much of the optical light path and I had trouble coming to focus so I had to add a 1.6x optical corrector system Barlow lens in front of the binoviewers.  By making the focal length longer by 1.6 times, I was able to reach focus on my Explore Scientific 102mm APO refractor telescope.  

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EDIT:  I would later find that if I used a different diagonal, I actually could come to focus with the Explore Scientific 102mm APO refractor telescope.  I have another diagonal that has a shorter optical light path than most so that one allows me to use the binoviewer without the 1.6x corrector lens.

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Now I need to start collecting a few pairs of decent eyepieces.  I have a good selection of high quality eyepieces but I don't have a lot of matching pairs that could be used in a binoviewer.  This evening, Sheila and I used a pair of 40mm Plossl eyepieces as well as a pair of 20mm Plossl eyepieces.  Both provided excellent views especially considering the fact that Plossl eyepieces are relatively inexpensive eyepieces.  Some of my eyepieces cost about ten times the cost of these Plossls yet these eyepieces still provided excellent views through this new binoviewer.  I was very impressed and a bit relieved that these inexpensive eyepieces worked so well.

I have matching pairs of Plossls at 20mm, 32mm and 40mm specifically for use in my Quark solar filter.  I want to get a pair of 25mm Plossls for this purpose as well.  The 25mm Plossls will work better in the Quark than the 20mm pair but the 20mm pair will still be useful for viewing other things in the night sky.  Since my primary reason for purchasing the binoviewer was for viewing the sun, I was already prepared with some pairs of eyepieces that work well with the Quark solar filter so I started viewing with these eyepiece pairs when viewing the moon.  

I'm really looking forward to using this binoviewer for solar observing.  Obviously, that will have to wait for a clear day when the sun is shining brightly.  Many astronomers have told me that binoviewers are known to be spectacular for solar observing so I'm looking forward to some two eye solar observing.  

Some telescopes don't work at all with binoviewers.  Some telescopes work very well.  Others can be slightly adapted to work well with binoviewers.  I had some nice success with my two most used refractor telescopes when viewing the moon and a couple of planets.  I hope to test a few more of my telescopes in the coming days and evenings especially when observing the sun.