First Stages of building a Portable Newtonian

[nobby2 (Neil)]

An undercoat/sealant day using a spray can. One can didn't go far! Have to return tomorrow for some more! Yes using spray cans is going to be to expensive. Better to purchase the 1 liter paint tin option.

[nobby2 (Neil)]

Nervous time cutting out room for the block in the Alt beams. Used a template of the side of the mirror box to attempt to get a close fit. Still required a long time sanding and fitting. Great on one side, not so good on the smaller cutout side. Time to keep up the undercoat while the wet paint is kept inside gladwrap.

[nobby2 (Neil)]

Time to get the painting clothes on for a flat black on everything including me. Have to complete the secondary cage later which still has the important markings on it to mount the focus board into the center of the cage.

[nobby2 (Neil)]

Its not something I gave much thought to until today. Is there a compelling/practical reason why one is better than the other? You will notice in the pictures I have already drilled the mounting holes so that the nobs are at right angles to the light axis of the telescope. e.g except for zenith, the fine tuning knob would be above the eyepiece. It gives me more room!
Given my preferred orientation of stars to the left: I have pictures of the three alternatives as I see it.
1. Orientation as above
2. Orientation is parallel with the telescope axis. e.g Fine tuning nob on the right, except for approaching Zenith when it becomes below the eyepiece.
3. At about 45 degrees to the Axis of the telescope.

[nobby2 (Neil)]

The completed mirror cell.
The main departure from the Albert Highe model is the use of one spring placed over each collimation screw rather then recessed in a hole either side of the collimation screw.

[starman345 (Brian)]

I have my Moonlite mounted as in your first picture with the dual speed knobs on the right side, I observe with my right eye and have the focuser on the left side of the scope (facing the scope from the rear) but really, I think it comes down to what is comfortable for the individual, I don't believe there is a wrong way. It would be nice if the Moonlite had a rotatable base like the Feathertouch does.

[nobby2 (Neil)]

Cutting out the thin strips for the Alt beams, gluing and sanding. Also shaping and gluing the laminate for the bottom of the rocker. Had to perform a small join to make up for the only width of Ebony Star I had.

[nobby2 (Neil)]

Starting to get there
Mechanics of Alt and Azimuth completed. Feels solid if nothing else. Still to go:
Alignment of focus board. May use my laser.
Install focuser, spider and holder and align.
Glue primary mirror to cell.
Test focal length and resize poles

[nobby2 (Neil)]

Checking how aligned the focuser board was after installing the focuser and using my laser against a rough cardboard screen. Began inserting the focuser board with screws and then changed to using m5 bolts to allow more control. Elongating the holes permitted a small amount of twist.

Inserted the spider and removed bolts and washers from the holder stem to get as close to the middle of the secondary at 7" from the top or 5" from the bottom.

Pasted a paper template of the secondary onto the holder with cross lines to indicate the center.

So far I have been able to make up for the small degrees of error such as:

• secondary rings not exactly round.
• Secondary poles not exactly the same distance from each other (spider still fits)
• Focus board attached to the rings by screws not bolts.

[nobby2 (Neil)]

I couldn't have hoped for a better outcome. I was preparing for all kinds of ' not ready yet' scenarios.
Glued (Silicone) the primary to the cell using small furniture door pads as spacers.
Placed the diagonal mirror through the back of the secondary holder up to the bevel and padded with nylon wool.
Installed the primary through the three collimation holes on the bottom mirror box board and was ready to go!
Used the collimating eyepiece with the crosshairs to center the focuser into the middle of the diagonal.
Used a laser pointer to align the primary mirror. Relieved that the ONE spring around each of the three collimating screws worked i.e. they had enough force to move and hold the mirror 7-8 kg.

Dragged the scope out of the garage to find a target (the moon), placed my 20mm plossl eyepiece and within moments achieved sharp focus.
Tested through to my heavy eyepiece achieving great focus and importantly balance.
What a rush of self fulfillment!
Still have small bits to do:
Install the secondary cage light baffle.
Install my finder (8*50) correct image.

[starman345 (Brian)]

Neil, congratulations on a beautiful result!, that telescope will give you many nights of enjoyment

[nobby2 (Neil)]

By just adding 2 wheels to the rocker I can tilt the scope to get it out of the garage. May add a handle on the opposite side.

[nobby2 (Neil)]

While any project is never completed I am calling it COMPLETED. I am happy to answer any questions re: Lessons learned along the way. I built up a spreadsheet of every invoice since the start (March 2015). This includes capital equipment and tools as I was starting from a low equipment base.

If I guessed from the start I would have said the budget would be around $2000. The final total was $3500.
This included sourcing mirror, focuser, spider and holder and teflon bearings from the US and the valuation of the Australian dollar and shipping costs.

I am now in a new phase of fine tuning and finding out how robust the build is. How will the collimation hold, How will the poles break down and re-assemble etc.

The mirror was from Hubble Optics. The spider holder and bearings kit was from AstroSystems and the Focuser was from Moonlight. Most other parts where purchased locally through the large hardware store chain.

[starman345 (Brian)]

Neil, my Hubble Optics 14" mirror scope ended up being a bit cheaper but not by much, it was a few years ago and those parts I had to source from the US were at a more favorable exchange rate than these days.
I may have missed it but didn't notice any mention of weight, did you ever put it on the scales? Also, what was the focal ratio of the 14" Hubble? Probably around 4.5?

[nobby2 (Neil)]

Here is the final weight. Weighing myself then holding each assembly.

Weighed in kg will convert to lbs at the bottom
UOA = 4.5 kg
Poles = 2.9 kg
LOA (mirror box)= 20.2 kg
Rocker, ground board = 7.1 kg
Total Scope Weight = 34.7 kg
Without rocker = 27.6 kg
does not include heaviest eyepiece = 0.7 kg

Converted to lbs
UOA = 9.9 lbs
Poles = 6.38 lbs
LOA = 44.44 lbs
Rocker = 15.62 lbs
Total Scope Weight = 76.34 lbs
Without rocker = 60.72 lbs
does not include heaviest eyepiece = 1.54lbs

[nobby2 (Neil)]

Final images in better light.