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Telescope Maker's Corner

Moon Killer by Rick Walker

In 2006, Rick Walker was on a business trip in California (his home state) and in looking for something to do one night he scanned event websites for any local happenings.  He saw a sidewalk event listed at a park in Burbank and drove from the South Bay to attend.

 

There he met Bob Alborizan with his 8 inch home-made telescope.  After looking through the scope, Rick and Bob talked for a while.  It is here that Rick heard about John Dobson, his mission and success of astronomy outreach using homemade large aperture telescopes.

 

Upon returning home, Rick scheduled a trip to take an astronomy class offered by San Francisco State University and needed two scopes, one for him and the other for his wife.  So now was the time to make a telescope. Rick planned a 6 inch telescope from the Ray Cash plans on the San Francisco Sidewalk Astronomer website, with hopes to make something bigger in the future.

 

Due to a mirror shipment issue – a 10 inch Celestron Dobsonian was purchased for the trip.  Then the trip had to be cancelled due to a work necessity – then the mirror showed up – Of course!  So he thought he just might as well put it together.

 

When the opportunity came to hold telescope making workshops his club, BA Sidewalk Astronomer, Rick now had the excuse to make his larger scope - 8 inch f/8. Starting with the Ray Cash plans again, this time he made a few alterations.  On the eight inch telescope a purchased spider was used to make sure it would be durable and easily collimated for long term simple use.  He also chose a light weight helical focuser in place of the plumbing fitting focuser due to his eye sight issues – this way it would allow others to have a better view with ease of focusing. 

 

As far as the mirror cell, on the 6 inch scope Ray Cash instructions were followed but this time he discovered another method from the NEAF website that he used on the 8 inch.  During this part of the process, Rick learned a new method to position the distance from the eyepiece for mirror placement.  On the 6 inch he mounted the mirror first then made the calculations.  Rick drilled the hole and mounted the focuser and could not get the scope into focus. This forced him to make another tube due to his mistake.  On the 8 inch tube, he drilled the hole, mounted the focuser, put an eyepiece in the focuser and then slid the mirror up and down in the tube until it came into focus.  He marked the spot and mounted the mirror cell there.

 

Another lesson learned - on the 6 inch scope, he did not use a textured laminate like Ebony Star, which resulted in the scope to not have a smooth azimuth movement like it should.  However, on the 8 inch scope, Rick followed John Dobson’s suggestion for an azimuth bearing method – an old vinyl record album.  So he went to go Good Will Store (since those are a thing of the past) and ensured that an Emerson – Lake and Palmer album was not sacrificed…………… and purchased an album of old show tunes.  To help with the ambient light on the sidewalk, Rick also extended the tube length further in front of the focuser to reduce the glare from street lights.   That has proven to be a great decision.

 

 

The “Moon Killer” as it is affectionately called, has much better lunar sights than his 12 inch Zummel telescope.  Plus it is a great advertisement with his club name painted on the side, BA Sidewalk Astronomer.  This year his name “Moon Killer” was painted on the other side before attending the Starlight Festival in Big Bear California in May.  This term of endearment was chosen because of the phenomenal sights of the Moon due to the longer focal length.  On first light, the Moon Killer was set up in front of a Starbuck’s Coffee Shop, were a transit shadow of the moon Metis crossing Jupiter (verified by three other people and identified on Stellarium) was observed.  When Rick posted that very happening on FaceBook, he was challenged because no one thought that was possible.

 

The Moon Killer is BA Sidewalk Astronomer’s main scope for outreach and has been a great hands-on scope for kids to learn and use at events.  BASWA allows for folks to touch and use the scope to find objects for themselves.  This scope has quite a following……..

 

Moon Killer was taken to the Starlight Festival and set up on the main streeet (photo to right) and showed a couple hundred folks each night, the planets over Big Bear, California. 

 

For the Moon Killer’s activities got to: Facebook: BASidewalk Astronomer

Tweet: BAsidewalkastro