Deadening a 150mm f/5 Newtonian

[Alan64]

...and to all manner of stray-light, whether it be artificial or natural.  Blacker than the darkest of dark nebulae it shall become wi'in; as black as a black hole e'en.  The patient, a base-model Synta with a 1.25" plastic focusser, is ready...

One might readily see the need.  What a reflective mess...

 

[Alan64]

To begin, the optical tube's components were removed and set aside.  Next, the outside of the tube was sealed, including all of the holes, then the interior sprayed with clear-gloss enamel, and for improved adhesion of the self-adhesive flocking...

Before flocking the optical tube, the individual components were flocked and blackened.  First, the focusser...

The drawtube was flocked, various areas blackened, the glue-like grease removed and replaced with Superlube(a Teflon-based grease), and the plastic drawtube shims replaced with self-adhesive felt.  It now seems a bit tighter, with less slop, and smoother in operation.

[Alan64]

The paint used to blacken the components...

The optical-flat assembly before and after blackening.  The assembly was in and of itself a reflective mess also...

[Alan64]

The primary mirror assembly, exploded...

The primary mirror cell required blackening in various and sundry areas...

Synta's flat-black isn't as black as my ultra-flat black...naughty naughty, Synta...

I decided against painting the primary mirror's edge, and for ease in re-coating in future, notwithstanding replacing both mirrors outright.  But, I had no choice in painting the secondary mirror, its edge and backside, as I didn't want to add any thickness, however slight, to the edge.  It's obstructive enough as it is.  However, I did flock the edge of the primary mirror...

Before, at left, and after...

[Alan64]

The optical tube was flocked either before or after the components were treated, I can't recall exactly, but no matter.  I've been at this project for almost a month now.

I've had a roll of Protostar flocking for seven years, and I thought it was about time I made use of it.  Measurements of the optical tube's interior were made, then the resulting sheet was cut into six strips, and numbered before cutting, not unlike a puzzle, and for a seamless fit...

The first strip was laid, centered, over the seam of the metal tube, then the rest applied in order...

 

[Stu]

Nice project Alan. I look forward to hearing about your first light with it after completion ?

[Alan64]

This tube-reinforcement plate for the red-dot finder's base almost struck the secondary when it fell, and when the components were removed earlier during this project, as I didn't know it existed at the time.  In any event, before going back into place, it had to be flocked...

Here, the finder's base and the focusser have been reinstalled, and the tips of their screws and the nuts blackened...

The secondary-spider assembly's nuts jut inward slightly into the tube's interior, therefore those portions were also blackened...

The project is now complete, and I couldn't be more satisfied with the results...

A first-light report will be forthcoming; and yes, true to the "curse", just as I had completed this project this last evening, in came the clouds. 

Thank you for looking.

[Tinker1947]

Well done, a nice job, i must say when i flocked my 250P-DS i can't say it may any difference but its in your mind,  its got to be better.....

[Alan64]

The first thing I'll want to test is when observing the Trapezium in Orion with my new 30mm Vixen NPL Plossl, and at 25x.  Before I began the project, I was almost able to split the close pair of the four stars visible.  I hope to see a definite separation upon the test.

[Alan64]

It's overcast today, of course.  So the ol' gal begged me to conduct a photo-shoot, and I obliged...

 

Before and after...

 

The infamous "secondary shadow", as seen during the day, and courtesy of the 25mm(30x) Parks GS...

 

The camera, as usual, cannot do justice compared to a live view, therefore I am a happy camper!