New Moonlite Focuser

I'm replacing the stock 2 speed focuser with a new Moonlite Dual Rate Tri-Knob focuser with the 1.75" compression ring draw tube.

The stock focuser was a little sticky even after doing the GSO tune up from some very good, detailed instructions on polluxchung website.

The new Moonlite focuser is very smooth and buttery.  I can turn the knob to focus without the sticky click from the stock focuser.

Stock focuser.

Side by side comparison.

First attach the curved mounting plate to the tube by matching the existing holes to the hole patterns in the base plate.  I used the provided screws to attach the base from inside the tube.

From the universal install kit I chose the 1/2" and 1/4" spacers for the correct height.

3 sets of different length screws are provided.  Find the correct length and attach the fosuser to the mounts.

Collimate and it's done!

The new focuser ready for night!

Making a secondary holder for the new secondary mirror

I got a new secondary mirror from Antares Optics.  The new mirror is a 2.6 minor axis, 1/18 wave PV.

  The old mirror is a 2.48 minor axis and fits inside a casing that is part of the stock holder.  The new mirror is too long and too wide to fit into the casing so I had to make a new holder.
   I bought the 2" holder from Destiny but had to do some modifications to it to make it work in my scope.
   I thought that the holder was plastic but it turns out to be cut from a 2" wooden dowel.  If I had to do it again I would have just made my own from the start but anyway, here is how it went.

New holder next to the stock holder

First I had to take the long screw out of the holder.  There was a wood plug that was pressure fit in to keep the screw from falling out.  I used a long screw from the other side and a pair of pliers to pull it out and remove the screw.

The plug was then glued back in and drilled out to fit a brass wood insert nut.  The holder will go back on to the spider and held in with a flat phillips screw.  Much the same way as the stock holder.

Since the holder was too long I had to cut it shorter with a saw.  If the holder was solid I could have cut it flat from the bottom but since I had to use the existing hole and plug to hold the insert nut I had to cut the 45 degree angle from the top end.  

  I'm using a safety cord to hold the mirror onto the holder just in case the silicone fails.  I read about this on the internet forum boards. Better safe than sorry!

I drilled a hole into the side of the holder where I will slide a length of  paracord (with the inside pulled out so it would sit flat on the back of the mirror).  Now its ready for the mirror!

First, I cleaned the back of the mirror with alcohol.  Then glued the safety cord to the back. I made a pattern of where the silicone blobs would be and used Zap A Gap CA+ to attach the cord to the back of the mirror between where the blobs would go.  The tissue the mirror is sitting on is the same tissue that was used to ship the mirror.  I don't know exactly what it is but if it was used by Antares then I'm sure it's safe.

After sitting for a day it was time to attach the holder.  I put three blobs of black Aqueon Aquarium Sealant on the back of the mirror with toothpicks as spacers. I pulled some of the safety cord through the hole to take up some slack. Then carefully put the holder on pushing it down until it was against the toothpick spacers. 

After letting it sit for 24 hours I pushed a piece of the toothpick into the hole with the paracord, cut it flat and put a little dab of Zap A Gap to keep it all in.

Here is the new holder and mirror compared to the stock.

I let it sit for another day and painted the back and sides of the mirror.

  For this I used flat black spray paint that I sprayed into the lid and very carefully applied it to the mirror with a brush.  I used a cheap brush I had and had to use a pair of scissors to trim the loose bristles.  Next time i'll just buy a better brush. 

The finished product ready for the scope!

Primary mirror boundary layer ring baffle

After reading about better ways to cool the primary mirror I came across a discussion on the internet forums about a ring baffle installed just above the primary mirror.
The purpose of the ring is to redirect the air from the fan across the top of the primary to help scrub the warm air boundary layer that sits on the face of the mirror.

This is what I came up with:

I found a 12" ring from Michael's. The ring is made from biodegradable wood fibers making it easy to sand and file.
First I traced an outline of the ring to help keep track of the measurements and make sure it stayed round.
I filed and sanded smooth the outside of the ring until it was slightly smaller than 12" to make a snug fit in the tube.
The primary mirror is 9 3/4" so the inside was filed and sanded to be just a hair bigger so none of the mirror face was being blocked by the ring.

After filing to size I painted the ring flat black then used flocking paper for the top just to make sure it was dark in the tube.
I'm attaching the ring to the primary clips so I drilled out holes for the screws and filed a notch to fit over the seam in the telescope tube.

Making sure it all fits right!

Here is the completed boundary layer ring baffle attached to the cell with the freshly cleaned primary mirror ready to go back into the tube!