Saturday, June 19, 2021

Lying on the Grass, Waiting for the Stars to Come Out

It is a lovely evening.  The atmosphere is clear and calm.  I started with the 85mm eyepiece (23x and about a degree field of view which I will use when hunting for galaxies and went up to 4mm (500x) which is just a bit too much for the conditions.   The image starts to fuzz.  At 5mm (400x) the image is still crisp.   I am glad that I spent the extra money for a dual speed focuser with both a coarse and a fine focus knob.  

The place where most low priced telescopes disappoint are the standard eyepieces.   They are often low quality with narrow fields of view.  Even the cheap department store telescopes can be markedly improved with $200 worth of decent eyepieces. 

Big Bertha came with 2" diameter University Optics 18mm orthoscopic.  I had never owned anything but a 1.25" diameter eyepiece before and it was startling how much it widened the field of view.   Since then I have acquired 50mm and 85mm 2" diameter eyepieces and I am very glad that I did.  When I get my 8" f/7 reflector mounted on my new whizbang Losmandy mount I will use the 2" to 1.25" adapter and see how this works with these 2" eyepieces. 

The stars finally came out, so I decided to use Sky Commander.  This is a digital setting circles gadget with which I have had intermittent success over the years.  You pick two stars on which you are going to align, aim the telescope at each star, and then press enter.  The more precisely you center those stars in the eyepiece, the more skillfully it helps you find items in its roughly 8000 object catalog.  The higher power the eyepiece you use for centering the guide stars the more likely that you will have them precisely centered. I used 160x to align on Arcturus and Vega and when I asked for the globular cluster M13 in Hercules (barely visible to the naked eye on a Moonless night). It then tells you how many degrees in altitude and azimuth to move the scope.  Using a low power and therefore wise field eyepiece put M13 where I was would see it.  The Moon still washed out its "diamonds on black velvet" appearance.  I also need to write a light shroud around Big Bertha.  This open framework half-Serriuer truss is adequate for bright objects with little ambient light, but the solar powered night lights that Rhonda put out so that I would not trip in the darkness (she knows me well) are just enough ro be a problem. 

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