Alan64

The first "button" was sawn, and at 6mm in thickness...

However, I decided to discard that one.  I then set the thickness at 5.5mm...

All that glitters, is gold, albeit a fool's gold...

The original black-plastic "buttons" are 5.08mm in thickness.  Let's just round that off to 6mm, shall we...

I took a hack-saw, with a special metal-cutting blade, and used the drill-press vise to square the previously-cut(by the seller or other) end...

It's okay, for government work.  But then it dawned on me.  Why don't I use my miniature, Preac table-saw instead...

I got that table-saw years ago, and with largest-table option available.  Sadly, it is no longer made, and parts for it are as scarce as proverbial hens' teeth.  But where there's a will there's a way, if the need arises.

Before sawing the rod for the "buttons", I will want to sand the rod in that area down a bit, and to ensure a good fitting.  

7 hours ago, Starslayer said:

Again, still confused. See pics attached above.  My 2' diagonal will screw direct onto the back of the scope ( although I also question the benefit of that as the 'hole' at the back is only 1 1/4 anyway - another issue ). I therefore do not need another visual back to attach it to the scope to use it.  

The purpose in getting a 2" diagonal in the first place, is to use low-power 2" eyepieces, with their wider, yea, widest, fields-of-view.  There is a 2" 56mm Plossl on the market, or was as it was branded "Meade", and it is sometimes chosen by owners of the larger Schmidt-Cassegrains.

But the primary-mirror of your C6 has a too-small hole in the centre of it to make use of 2" accessories...

Using the 2" diagonal would essentially be the same as using a 1.25" diagonal, yet at a greater, unnecessary expenditure.

This is the hole in the centre of a C8...

As you can see, the prospect of using 2" accessories is improved.  This increases further as you go up in aperture.

In the end, I would suggest, only to suggest, selling the 2" diagonal.  Then, to suggest the Celestron star-prism instead; for example...

https://www.rothervalleyoptics.co.uk/celestron-90-degree-star-diagonal-125.html

In the past, that's the diagonal with which these Celestron SCTs came equipped, and for good reason.  The C8 may still come equipped with that one.  You might also consider the Baader...

https://www.firstlightoptics.com/diagonals/baader-t-2-prism-star-diagonal-32mm.html

It is modular, and allows you choose how to configure it.  Then, to combine either one with a 1.25" 32mm Plossl, and for the lowest power and widest view possible.  Some also choose a 40mm, but I digress.

There is the Celestron focal-reducer, however it might not live up to your expectations...

https://www.firstlightoptics.com/reducersflatteners/celestron-f63-focal-reducer.html

You're not the first in desiring all-round performance with a Schmidt-Cassegrain, but the telescope is simply not designed and configured for low-power, wide-field views.  Your C6, similarly as my Maksutov, is for medium-to-high powered observations.  They're like microscopes, but for the night sky.

If 2" eyepieces and accessories to improve finding one's way round the sky, I suggest looking into a more capable finder.

It is curious as to why your telescope came equipped with an Amici, erect-image diagonal.  I have to wonder if it's intended to work with the "StarSense" system.

Firstly, your 2" "XLT" diagonal is a star-mirror, not a star-prism.

Yes, you need a 2" visual-back to insert your 2" star-mirror diagonal.  Else, you cannot use it.  If you have been able to insert your 2" diagonal all along, then the telescope already has a 2" visual-back.

The visual-back is the hole into which you insert an eyepiece, a barlow, a diagonal.  This is my Maksutov-Cassegrain, and similar to your Schmidt-Cassegrain...

It has a 1.25" visual-back, therefore I cannot insert a 2" anything.

What is the exact nature of your Schmidt-Cassegrain?  Is it a Celestron C6, C8, C9.25, or is it a Meade?

The first thing that popped into my mind when thinking about how to go about cutting the brass rod square and true was my trusty Sears Craftsman 4" drill-press vise...

That vise was a great buy at the time, new old-stock, and for US$50.  I just spent about two hours cleaning it up.  I had left it out of its box, and it became fouled with rust and other.  It's now back to its old self again.

Now to decide what to do next...

Indeed, among all reflectors, the Maksutov is considered to be the nearest equivalent to a refractor.  My 127mm f/15 Maksutov...

...is a simulation of a 102mm f/19 to 115mm f/17 achromatic-refractor.

I knew about the problems with a 180mm Maksutov, but I couldn't put that much outlay into one anyway.  I did think about a 150mm, but then read of acclimating issues of its own.  

I feel that a 127mm is the "sweet spot" among the varying apertures of the design; not too small, not too big, just right rather. 

Maksutovs are the least likely among reflectors to require collimation, either upon arrival or over the course of ownership.  But if and when time comes to collimate one, it can just as difficult as that of a Newtonian, if not more so.  Schmidt-Cassegrains are the easiest of reflectors to collimate, but I'm not particularly fond of their secondary-obstructions, and will most likely never own one as a result.

Although, I would most definitely give a classical-cassegrain a whirl round the celestial dance-floor.

There is one thing about Maksutovs that I've noticed, personally.  I can sense the meniscus whilst observing.  I can almost "see" it.  They are rather thick.

4 hours ago, Mogra1 said:

Hi,

      We  were able to set up finderscope and see the moon clearly.

However when we try to see Jupiter OR Saturn we are seeing a black dot when we try to see more details. 

It looks like a shadow on the image. A black spot with spider vanes.

i think our scope is collimated correctly as i can see the moon clearly.

Any suggestions.

Thanks

 

 

Hello,

The Moon is the object nearest to the Earth, and rather large.  It can appear clear, sharp somewhat, but objects that are farther away, much farther away, require the collimation to be spot on; and for sharp, pleasing images at the higher and highest powers.  Does your telescope's main mirror, at the bottom of the tube, have a centre-spot, like this...

You can shine a torch down the tube to find out.  

This particular, ordinary brass is type H62(softer than H59), an alpha-beta brass, being roughly 62% copper, and the rest of zinc.  

Moh's...

Copper: 2.5 - 3

Zinc: 2.5, same as gold

Brass: 3

Bronze: 3

Aluminum: 2.5 - 3

After all, I wouldn't want this to happen...

I'm not substituting this brass for plastic.  Rather, the mount-head arrived with a substitute...

Incredible; the J-B-Weld set rather hard after just five hours.  I suspect it was due to it being summer...

There's now a considerable gap between the saddle-plate and the worm-assembly...

Voilà ...

Just as for the RA-worm, I adjusted that of the DEC where I could detect no side to side movement, but only a slight "knock".  The worm-shaft does not rotate quite as freely as that of the RA-axis, but there's no binding.  I couldn't turn it at all upon arrival.  The DEC-axis itself does not rotate as easily, either, but smoothly nonetheless.  It simply requires a bit more force, is all.  That may be due to the worm-gear fitting ever so snugly within its cavity.  Although, that may be beneficial actually once a telescope is attached to its saddle.   But none of that matters, really, as it's only the DEC-axis.  It's the RA-axis that really counts, and...it...is...superb.  But you won't know for yourself unless you do everything I did.

I can't place the mount-head onto the tripod for a glamour shot, without clamps, as the DEC will drop upside-down.  I may receive the brass rod tomorrow, however. 

But going back when the mount-head first arrived, and without clamps then...

...I could pose it like that, as the axes were bound-up, stiff.

Incidentally, all surfaces to be joined, including on the top of the DEC-shaft, were rough-sanded, scored with a utility-blade, then cleaned with 100% acetone....

Never use even 91% isopropyl-alcohol to clean and de-grease when using J-B Weld.

J-B Weld steel-reinforced epoxy...

Until this time tomorrow I will have to wait.

Synta!

I just had to let loose there.

Aren't they lovely?

I began to make the larger, single partial-circle, and for the elevation of the mount's saddle...

The brass there was an attempt to keep from marring the aluminum whilst clamped for dressing.

Inadvertently however, somehow I had cut it down too short in its curved length.  What do you do when you're handed a bag of lemonades, and instead of that Aston Martin you were expecting?  You make lemonade, the two smaller pieces, from the "bag"...

Those are actually much more difficult to make, as they had to be, essentially, sculpted, so it turned out well in the end.  I got those out of the way, first.

The aluminum I'm using is from a narrow strip, and a mere frog-hair thicker than 1.5mm...

Yes, it's a great tragedy that I'm having to do this.  I don't think I would've had to have done this to my old Vixen.

I've run into a problem when attaching the saddle atop the DEC-shaft, and just above the worm-assembly.  When the saddle is battened down, it presses on top of the worm-assembly, making it tighter than normal, normal being when I effect the best position of the worm in relation to the gear.  For this section that sticks out over the worm-assembly, I removed the paint and sanded it down...

That's the section where a motor-drive is attached.  Removing the paint and sanding the section's underside helped a bit, but it still required those washers(at left) on the underside of the saddle to elevate it.  But those washers are not the proper way to elevate the saddle.  This, rather...

Those three unpainted areas are slightly higher than the painted surfaces surrounding them.  I will need to thicken those three areas instead of using the washers.  1.5mm to 2mm should do the trick.

Now I know why the DEC-axis was bound-up upon arrival.

Firstly, the cavity for the worm-gear was greased.  I even filled that narrow channel round...

The washer and the worm-gear were totally saturated with grease and set into place.  If you look sharp, you can see a bit of the washer peeking out from the grease...

The DEC-shaft was greased where needed, then the two sections were combined...

Just as I did for the RA-axis, the lock-nut was brought to a dead-stop, then backed off a quarter of a turn.  The two set-screws were then tightened.

I do grab each axis by their ends, then pull them, and in trying to detect any slop, which I did not with either, none whatsoever...

The motions are, well, out of this world.

Now for the worm...

There's a video on YouTube where the author states not to grease the outside surfaces of the worm-gears(for a go-to EQ-5), as that's where a clamp engages same, and to lock the axis, the premise being that the grease would allow the gear to move despite being locked.

I greased the outside of the RA-worm gear, but it doesn't drop in to a tight-fitting cavity, as the worm-gear for DEC-axis certainly does...

Indeed, the outside of that worm-gear has scratches from placing and removing it several times, most tightly fitting it is, therefore it will have to be greased.  I can see the black-plastic clamping "buttons" giving way, but I'm hoping that their brass replacements will not.  The brass rod, incidentally, is due to arrive in three days, but I won't be holding my breath.

The time has come...

This is the lens-cell from a 90mm achromat that I have...

You can see the retaining-ring there.  What you want to do is loosen the ring, then screw it back in slowly until it comes to a dead stop, then back it off just a quarter of a turn.  That will allow the doublet to expand, room to spread out.  You may hear a slight rattling of the lenses on occasion afterwards, but no harm done.

I had originally gotten these shears for cutting things related to my shed, but they have become a blessing in being able to cut this thicker bronze...

You can see how rough they are round the edges.  I did cut them neatly, and very close to the line.

The washers were then sanded and polished...

Plenty of room for the lock-nut...

...and that useless setting-circle.

Next, to re-assemble the DEC-axis...

The bronze washer for the mid-section of the DEC-axis is completed...

I'm puzzled, as I had to grind beyond the outer line, inward, before the washer would drop in; strange, but all's well that ends well. 

This union is where I thought I would need to add a washer.  I placed a small amount of the blue grease I bought, indicated by the white arrow...

I then combined the two sections, with both bronze washers installed, twisted the two sections together a little, then separated them.  Only a tiny smear, and from the top of the glob, was evident on the opposite surface, indicated by the grey arrow.  Hence, there's a gap there between the two surfaces, thankfully, and a washer will not be required.  But I will grease those surfaces nonetheless before reassembling.

Now to prepare the washers for the needle-thrust bearing...

The upper(worm) DEC washer, sanded(inner/outer edges only) and polished...

From directly above, all of the worm-gear's teeth are visible...

The upper(worm) DEC washer, and dressed only...

I have a couple of Dremel #407 sanding-drum bits, somewhere, but I can't find them at the moment.  But I did find my late father's, which seems to be a bit on the heavy-duty side...

The nut screws on in reverse, towards the left, rather than to the right.

This sanding-drum will remove the excess bronze without building the metal up at the edge, which would require an extra step to remove that.  I got these grinding-stones recently, and used one for dressing the RA washers...

They work wonderfully, but the metal tends to build up at the edge.  I'm going to use the sanding-drum at first, to remove the bulk, then the grinding-stone to close in.  The sanding-drum, however, is spent much more quickly than the stone.