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Improving a 150 mm Newtonian W/Dobsom mount

beginner dob accessories equipment
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#1 FredOz

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Posted 03 June 2020 - 01:58 PM

Hi All,

 

Here's an attempt to pass on some suggested modifications I made to my Skywatcher 150 telescope.  Many of these were per suggestions on the Cloudy Nights forum.

 

  • Added 5 eyepieces to the 2 supplied with the scope
  • Replaced supplied 6x30 finder with 8x50 mm Right Angle Correct-Image Finder
  • Added red-dot finder (for rough pointing)
  • Added thin Lazy Susan bearing for smoother swiveling in azimuth
  • Added magnet for tube balance weight
  • Painted protective caps orange so they don't get lost if dropped
  • Added 15" homemade stool to lift telescope to convenient height per
    http://eyesonthesky....eTripod2x4.aspx

The stool described in Eyes on the Sky is for a tabletop telescope, so I made changes in the design:

  • My stool is only 15" high because my scope is bigger
  • Eliminated hinges for folding the legs
  • Turned 2x4 legs 90 deg to make legs stronger
  • Fastened legs with deck screws through top plus clips on bottom
  • Fastened brace/shelf with angle brackets.  Holes in shelf can hold eyepieces.
  • Bored hole in top for bolt at bottom of telescope mount

 

The stool top is a 15" pine circle.  This is smaller than the diameter of the plastic feet on the telescope so the feet hang over the sides.  Thus I needed to bore a hole for the bottom bolt on the telescope.  The stool is rigid and with three legs, does not rock unlike a 4-legged stool I was using.

 

I did not remove the Teflon pads on the base to better support the telescope.  But there was enough drag from the Teflon to make azimuth pointing difficult.  The cure was adding a thin piece of aluminum under the bearing to give a slight clearance to the pads.

 

Attached Thumbnails

  • Telescope & stool.JPG
  • Lazy Susan Telescope.jpg

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#2 SteveG

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Posted 03 June 2020 - 06:43 PM

Nice job! I probably did the most observing in my life with a 6" f8 reflector.



#3 clearwaterdave

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Posted 04 June 2020 - 04:13 AM

I am guessing you built the stand because bending over got to be a pain.,I found that sitting while at the eyepiece was much more comfy.,and made viewing easier.,I could be much steadier over the ep.,For my z8 an office chair was perfect.,best2u.,

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  • 20180507_185954.jpg(1).jpg.jpg


#4 dmgriff

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Posted 04 June 2020 - 09:46 AM

Good job....A 6in f/8 reflector is one of my mainstays.

 

You may consider a manual push to degree circle and/or altimeter  inclinometer.

 

 

I use a minimalist approach, just a inclinometer with some alt/az mounts, scopes. This is in lieu of a 1x visual finder in my increasingly light polluted backyard.

 

Look at my Messier Object Planisphere to find what I may like to view. Use my old Tasco planetarium software to obtain the azimuth and altitude at time period I will view. Such as South to South/SouthWest  and 65 degrees at about 9-10pm. Use a RACI from there. Getting LAZY...

 

Good viewing,

 

Dave


Edited by dmgriff, 04 June 2020 - 11:56 AM.


#5 Richie2shoes

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Posted 04 June 2020 - 02:31 PM

Nice job!  If you don't feel like lifting the scope onto your table, you can leave it on the ground and sit on the table.  I never thought of painting the protective caps.



#6 FredOz

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Posted 04 June 2020 - 05:54 PM

I am guessing you built the stand because bending over got to be a pain.,I found that sitting while at the eyepiece was much more comfy.,and made viewing easier.,I could be much steadier over the ep.,For my z8 an office chair was perfect.,best2u.,

I use my telescope in a gravel-covered front yard, trying to avoid excessively bright lights on neighbors' houses and I often take it to darker-sky locations.  Thus a chair would be awkward, especially in my small car.  So I'll stand.

 

On the painted eyecaps -- a couple weeks ago, after I'd set up the scope, as I was carrying the caps to my front patio using the large cap for the end of the tube as a tray, I noticed the small finder eyepiece cap was missing.  Next day I spent a couple hours searching for it before I gave up.  So I started painting.  I also found that a cap from a refrigerator filter fit after I glued felt on the inside.  But then next time I used the scope, when I took off the cap over the eyepiece tube, I found the finder's cap inside.  Although it was loose, it had not fallen into the tube.  But now my caps are painted (except the large one for the tube).  And now I have a spare cap for the finder.

 

I see I fatfingered typing Dobson but could not find a way to edit the post.

 

--- Fred


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