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New Member with 100mm Royal Astro telescope

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#1 humner

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Posted 02 August 2019 - 11:13 PM

Hi Everyone,

 

I'm new to the forum. I recently picked up a 100mm Royal Astro reflector telescope as my first scope and I'm having a lot of fun with it. I have had a few clear nights and have viewed Jupiter and Saturn and I really liked what I saw!

 

I decided on a vintage telescope as they appear very well made compared to the new cheaper scopes. I also am looking forward to restoring this as restoration projects are a big hobby of mine too.

 

Which brings me to my first question regarding this telescope which I'm hoping someone could shed some light on. I'm looking to remove the mirror assembly, however I can't see how this is done as the screws going into the side of the OTA which hold the mirror are screwed into small nuts which are not reachable. How do I remove the mirror?


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#2 dave brock

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Posted 03 August 2019 - 01:37 AM

If there are 3 sets of push/pull screws for collimation then you remove the pull screws. The cell will come out (and primary mirror). You can then access the nuts if you need to remove the rest of the assembly.

Edited by dave brock, 03 August 2019 - 02:00 AM.


#3 shredder1656

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Posted 03 August 2019 - 06:10 AM

Some photos would be awesome.  Congrats on a great scope!



#4 CharlieB

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Posted 03 August 2019 - 07:51 AM

If there are 3 sets of push/pull screws for collimation then you remove the pull screws. The cell will come out (and primary mirror). You can then access the nuts if you need to remove the rest of the assembly.

You really only need to remove three of the screws.  As you are looking at the back of the scope, there are three pairs of screws.  Remove the ones that are to the right of each pair. 


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#5 rcwolpert

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Posted 03 August 2019 - 05:47 PM

Hi Everyone,

 

I'm new to the forum. I recently picked up a 100mm Royal Astro reflector telescope as my first scope and I'm having a lot of fun with it. I have had a few clear nights and have viewed Jupiter and Saturn and I really liked what I saw!

 

I decided on a vintage telescope as they appear very well made compared to the new cheaper scopes. I also am looking forward to restoring this as restoration projects are a big hobby of mine too.

 

Which brings me to my first question regarding this telescope which I'm hoping someone could shed some light on. I'm looking to remove the mirror assembly, however I can't see how this is done as the screws going into the side of the OTA which hold the mirror are screwed into small nuts which are not reachable. How do I remove the mirror?

 

Wonderful telescope! Congrats and welcome to the forum!



#6 Defenderslideguitar

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Posted 03 August 2019 - 05:55 PM

Welcome aboard    you have come to the right place.  Nice scope to start with. 

 Some folks   here   not me  have so much experience that it is nothing to remove mirrors   lenses  and it    is all old hat to them.

 

I hesitate myself as I suffer from clumsyness and a former lack of patience.  Take pictures   take your time

 keep us posted



#7 dave brock

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Posted 03 August 2019 - 07:33 PM

You really only need to remove three of the screws. 

Isn't that what I said? smile.gif 



#8 humner

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Posted 03 August 2019 - 08:14 PM

Thank you all for the welcome and advice here. I'm sure I will have more question's while I restore this scope, with that being said its already in good condition to begin with.

 

As I have been enjoying the scope as is, I was hesitant to touch the collimation screws until I was ready to have a go at collimation. However I've now removed the mirror using the 3 screws and gave the mirror a rinse over with distilled water as per some guides I have read.

 

Its now clear of dust and looks to be in very good condition.

 

I was careful to leave the adjustment screws as they were and I also marked the assembly so it was returned in the right spot.

 

I have read about testing collimation with a bright star which I will do one clear evening - looking forward to it!

 

I will post up some pictures shortly.



#9 CharlieB

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Posted 03 August 2019 - 09:10 PM

Isn't that what I said? smile.gif

Sure did.  I misread.  My apology.

 

Charlie



#10 humner

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Posted 06 August 2019 - 07:15 AM

I was able to test the collimation on a bright star tonight and it appears good enough for now.

 

I also have 3 eyepieces. HM 25mm, HM 12.5mm and HM 6mm - are these considered good eyepieces? I don't have anything to compare too.

 

I have attached a picture. I recently added a motor to motorise the focus'er to minimize vibrations - it works very well.

 

scope1.jpg


Edited by humner, 06 August 2019 - 07:15 AM.

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#11 apfever

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Posted 06 August 2019 - 08:25 AM

If you are enjoying the views and having fun, then they are good eyepieces.

However, it would be easy to get even better eyepieces.  First, measure the eyepiece barrel diameters or the diameter of the focuser hole they go in.

The diameter should be either a little under 1" or distinctly bigger at 1.25"  (1-1/4").  While there are some better quality 0.965" eyepieces, you will find it a lot easier to experiment if you can get to the much more common 1.25" eyepieces. 

 

First, let us know what size your focuser takes.  There are a variety of adaptions to get from the 0.965" to the 1.25" size.



#12 starman876

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Posted 06 August 2019 - 09:35 AM

great looking setup.  These 100mm newts should be able to provide some great views.



#13 Joe Cepleur

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Posted 08 August 2019 - 05:18 PM

"3 eyepieces. HM 25mm, HM 12.5mm and HM 6mm - are these considered good eyepieces?"

If, like the telescope, the eyepieces were also made by Royal Astro, then they would be surprisingly good! "HM" stands for "Huygenian Mittenzway," a design of eyepiece that was often made cheaply, with horrific results. When well made, they have superb color correction, but also a narrow field of view and little eye relief (the eye must be quite close to the glass). That said, you would like modern eyepieces better. I keep my Royal Astro HMs as a collector, but actually use modern Plossls.

"I decided on a vintage telescope as they appear very well made compared to the new cheaper scopes."

It helps that you started with a Royal Astro! They are top-of-the-line!

Edited by Joe Cepleur, 08 August 2019 - 05:20 PM.


#14 humner

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Posted 16 August 2019 - 04:18 PM

Thanks for the comments on the eyepieces. I'm very happy I stumbled across the royal astro and get to start out with it.

 

They are the original eyepieces sold with the telescope. I had a good discussion with the last owner and he said he misplaced the 12.5mm and 6mm for years and only recently came across them, I was very glad he did!

 

What sparked me to get into this hobby was attending an outreach program a couple of months before(it was my girlfriends idea, so its all her fault!). I was lucky enough to see through many telescopes. During the first night with my royal astro, my girlfriend and I both agreed that the image through it was comparable, if not better than what we saw during the outreach night. Having that experience has really driven me into this even more, and I have been lucky enough to have many clear nights since then!

 

I also have a background in electronics and have already CNC'ed an aluminum bracket to connect a geared down motor to use as a clock drive for RA. The motor is rated at 0.6rpm at 12v. I have geared it down further to 0.24rpm, and then have used a PWM controller to bring it to the 0.1rpm required to track correctly.

 

I'm currently working on a slipper clutch so I can still use the manual control when needed. However at the moment its working OK as I can still manually adjust RA by loosening the RA axis clutch and nudging by hand - so its not an urgent part at the moment.

 

I have attached some pictures of my RA drive.

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  • 1.jpg

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#15 humner

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Posted 19 August 2019 - 09:01 PM

The RA drive is working perfectly. Its really is a joy to be able to track when viewing something at 6mm, walk away for 10 minutes and return with your object still in the eyepiece!

 

I can't tell which is more fun, looking at the sky or tinkering with the telescope, haha.

 

I'm wondering about collimation and which is the best method for this kind of telescope?

 

I have tried to test it using the star method, but I don't think I have had either good conditions or I'm pointing at a double/binary star and this maybe throwing things off? Can I collimate off a double star or do I need to find a bright single star?

 

If I eyeball the collimation, I can see the primary is centered (the 3 retaining clips are centered) which I believe tells me the secondary is pretty good, and then I can see the secondary/spider looks centered in relation to the primary which to me says the primary is close too.

 

I've ready that the smaller Newtonian's don't require a perfect collimation, but I want it to be the best it can be.


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#16 CharlieB

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Posted 19 August 2019 - 10:11 PM

Very nice drive you have there.  Well made!

 

As for collimation, I use a 1.25" collimation cap and a 1.25" to .965 adapter.  That gets me in the ballpark.  Then I use Polaris for tweaking.  The better the collimation, the better the views.

 

Here's a photo of the original drive in case you are interested.

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#17 humner

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Posted 19 August 2019 - 10:45 PM

That looks great. Does the coupler allow you to disengage the motor easily? Can you use the manual slow motion with the motor engaged?



#18 CharlieB

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Posted 20 August 2019 - 06:25 AM

The coupler is a clutch, essentially a compression fitting.  You just give a twist and you can use the manual controls.  Another twist, and the motor is re-engaged.  You can't use the slo-mo controls while the motor is engaged, though.



#19 humner

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Posted 23 August 2019 - 07:31 AM

So I had a good experience tonight.

 

Bit of back story, I bought/collected the telescope Saturday morning a few months ago, then on the Sunday of that same weekend we had a clear night and it was the first night I properly used it. My brother, girlfriend and I viewed Jupiter and Saturn that Sunday evening, and we were all amazed at what we saw - the Cassini division was clear that evening, the bands of Jupiter and the 4 visible moons were fantastic.

 

Since then Sydney has given us some very clear nights and I have been extremely lucky to use the telescope many times a week since then, however we have all noticed that it was never as good as that first Sunday evening...

 

Until this Friday evening. I setup the telescope and instantly noticed how much better it was. I called my brother out and he reacted the same way he did that Sunday evening. I was always wondering what everyone means about how good the "seeing" is in a particular night and now I finally know. The best part is also understanding that the HM eye pieces are still usable in 2019 and how much of an effect a particular night has on what you see.

 

I'm also fascinated with the orientation of the 4 visible moons of Jupiter and how they change -  earlier in the week my brother and I saw the 4 visible moons on one side of Jupiter and it was just a lovely sight.


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#20 humner

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Posted 23 August 2019 - 07:36 AM

Also, tonight my brother and I viewed Antares, right near Jupiter, such a great orange/yellow glow!



#21 humner

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Posted 04 September 2019 - 03:26 AM

The last week I have spent restoring parts of the scope. I have completely collimated the secondary and primary mirrors after removing the spider completely. I thought it was very ingenious that they used cotton to compress the secondary mirror in place - very clever!

 

The one part I'm curious about though is the RA clutch. Since I bought the scope I have never been able to completely lock down the RA, so I took this apart for a closer look and now know how it works. I have a few questions.

 

Should I be able to lock down the RA so it can't move?

Should there be lubrication around the brass finger/tab that locks down the RA?

 

I assume no, I feel like this is part of the scope that should have no lubrication, or maybe it needs a special kind. It appears the old grease/lube has seeped in from where the red paper/polylithic washers are.

 

My Dec clutch works perfectly, I can tighten it down, and it is smooth.

 

Cheers

 

Rob



#22 humner

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Posted 06 September 2019 - 01:29 AM

I had a closer look. So the RA brass finger/clamp is actually compressing against the RA slow gear and there are friction gaskets to mate this to the mount.

 

So really I need to grease this up and probably want to find a nice middle ground on smoothness and friction.




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