Orion SkyQuest XT 8 for £110? yep, I'll have that..

[Mr_Cat]

After my Jessops POS I got a decent telescope for Christmas (sky watcher 150P-DS)  but shortly after New Year I spotted a SkyQuest XT8 for £110 on Facebook marketplace

Did a bit of research, checked all the FB photos and figured it was worth a look. Cash in hand I took a trip out, gave it a look over and decided to buy it.

Got it home and it was a busy weekend so I didn't really get much time with it. It all worked, came with a 25mm plossi, and a shorty barlow, collimation cap and a lunar filter. 
First up checked the collimation and it was way off, so ten mins later it was fine. A good look at the primary showed it was dirty but decided not to worry about that for a while.

Got a quick look through it on the second night and it was working ok but there were a few issues..
So,  the list to be done..
Battery swap  and alignment in RDF
General clean
play in focuser
lots of stiction on both axis
Tube removal doesn't work.
clean main mirror

One of the things I've found with telescopes that I like is fixing things and learning new skills - so one by one I tackled the problems - removing the primary mirror and cleaning it properly had to have the highest pucker factor of all the jobs..
The tube couldn't be removed as the bushes the springs loop over had been put on the wrong way round.
All the PFTE bushes were very dirty, so cleaned them all, cleaned the base where it rests on the az bushes, then made some "milk jug" spacers for the centre bolt. 

But now it's all done I have a nice telescope for not much cash

I've been working on it in my garage and it's been quite good fun just to pop the door opener and see what I can see - it's been fortunate that in the evening the moon has been above my neighbours houses.

[cajen2]

Nice work, MC.

[bosun21]

The telescope tube is just meant to be lifted from the base once the tension spring has been released. The fittings on the tube itself are not supposed to come off.

[Mr_Cat]

2 minutes ago, bosun21 said:

The telescope tube is just meant to be lifted from the base once the tension spring has been released. The fittings on the tube itself are not supposed to come off.

I had phrased that badly - these fittings on the base were the wrong way around so when you pulled the spring down the loop on the end of the spring would not slip over the bushing.  This is now the correct way round - picture it with the thicker part of the bush against the screw head and the spring against the base.  The loop in the spring is too small to slip over the thicker part of the bushing.

[bosun21]

10 minutes ago, Mr_Cat said:

I had phrased that badly - these fittings on the base were the wrong way around so when you pulled the spring down the loop on the end of the spring would not slip over the bushing.  This is now the correct way round - picture it with the thicker part of the bush against the screw head and the spring against the base.  The loop in the spring is too small to slip over the thicker part of the bushing.

Got it 👍.

[Carbon Brush]

A good report. That is the great thing about newt reflectors an dob mounts. They are so easy to sort out.
Sounds like it was one of those scopes that got used a few times then left for years.
Enjoy your bargain.

[Mr_Cat]

On 22/01/2024 at 17:54, Carbon Brush said:

A good report. That is the great thing about newt reflectors an dob mounts. They are so easy to sort out.
Sounds like it was one of those scopes that got used a few times then left for years.
Enjoy your bargain.

Yeah - I'm guessing this is nine years old. there is a sticker on the base about formaldehyde 

Edited January 25 by Mr_Cat
spelling mistook

[Mr_Cat]

DOM..

Edited January 26 by Mr_Cat
it was meant to be a photo...

[Mr_Cat]

What do we reckon ? These are 50mm diameter. 
What will these do to the friction/ stiction on the horizontal rotation on the base???
My original thought was more surface area will spread the load / decrease the friction - but now I'm thinking the extra surface area is going to increase the stiction..

 

[PeterStudz]

What are they? What are they made of? I assume that they are new pads for the AZ bearing. And if so and when installed what do they run over? Is there any sort of textured surface? If not then there needs to be otherwise movement will be jerky and “sticky”. It’s often the case with these manufactured Dobs. Some get around this by using a lazy Susan for the bearing but I find that runs too freely.

When I made my base I cut my pads out of a Teflon sheet. And I have it running over cheap textured aluminium like this…

As for the right size for your bearings and setup the only way to find out is to try it and see. 
 

[Mr_Cat]

They are PFTE furniture sliders. I've stuck them to the side of the existing bearing so they don't get caught up on the bolts used for the vertical supports. The underside of the top of the mount (the upper bearing surface) isn't smooth - it's slightly crackled or crazed. 

The centre bolt has been spaced with PFTE washers - so they take most of the weight, I added / removed washers until there was no wobble in mount

Testing it afterwards was interesting  - I'd say the stiction had been reduced but the sliding friction had increased - which actually is better as it feels more consistent. You don't get that pull / overcome friction / rotate too far / move back cycle...


 

[Mr_Cat]

Decided to buy some tube rings and a dovetail to throw the OTA on my Eq3 to see what it was like.. (I know it's right on the weight limit but I'm looking for an Eq6..) 

I left the trunions on so it's relatively easy to put it back on the dobs base


I hadn't actually realised how much bigger it was than my 150...



And it went ok on the mount, I could actually balance it  - there is a "tremor" whenever you touch it as it is too big for the mount - but despite that it did work well. Huge difference in usability (IMHO) from the dobs.

[bosun21]

The dob base is much easier to use with the scope. Wait until you have the eyepiece pointing in unaccessible angles. I would also upgrade the tripod to a SS version for more weight as it looks like it could topple over at certain points.

[Mr_Cat]

6 minutes ago, bosun21 said:

The dob base is much easier to use with the scope. Wait until you have the eyepiece pointing in unaccessible angles. I would also upgrade the tripod to a SS version for more weight as it looks like it could topple over at certain points.

Thanks Bosun !
I've already had to rotate the tube - the trunions came in quite handy as I could loosen the clamps a lot with out worrying about the OTA sliding out - I'd had a look at the rotating rings thread before ordering the tube rings. It came in handy though - sometimes the Mrs struggles to view something I've been looking at (I'm 8" taller than her)  but as I'd rotated the tube it was much better placed for her. Definitely a silver lining on that one.

I'm looking for a EQR6 Pro with a new tripod  - I've got a chunk of cash and on the lookout for a s/h one.  Just waiting on some replies from sellers on Uk Astronomy buy & sell
 

[PeterStudz]

3 hours ago, bosun21 said:

The dob base is much easier to use with the scope. Wait until you have the eyepiece pointing in unaccessible angles. I would also upgrade the tripod to a SS version for more weight as it looks like it could topple over at certain points.

I Agree! There’s no contest. Eg the Dob base for my 8” that I made out of cheap plywood from Wicks is far more stable and more useable than the little 4.5” Newt that I have on a EQ5 steel tripod. The stability is so important as I can focus without wobbles. And it’s rock solid in a wind, unlike something on a tripod.

As for height. I’m 6ft tall and my 8 yr old daughter (no 12) is somewhat shorter. Easy to get around with an adjustable stool. I got this for £10 via Gumtree. She stands and I (being lazy and old) sit
 

[cajen2]

1 hour ago, PeterStudz said:

I’m 6ft tall and my 8 yr old daughter (no 12) is somewhat shorter. 

You have 12 daughters? 😱

[PeterStudz]

2 minutes ago, cajen2 said:

You have 12 daughters? 😱

You can’t have too many 😀

[Second Time Around]

3 hours ago, PeterStudz said:

I Agree! There’s no contest. Eg the Dob base for my 8” that I made out of cheap plywood from Wicks is far more stable and more useable than the little 4.5” Newt that I have on a EQ5 steel tripod. The stability is so important as I can focus without wobbles. And it’s rock solid in a wind, unlike something on a tripod.

As for height. I’m 6ft tall and my 8 yr old daughter (no 12) is somewhat shorter. Easy to get around with an adjustable stool. I got this for £10 via Gumtree. She stands and I (being lazy and old) sit
 

I love that stool!

[PeterStudz]

35 minutes ago, Second Time Around said:

I love that stool!

I rather like it too. And unlike most of my astronomy gear that my other-half thinks looks “ugly” or “shouldn’t be in the house” this stool is an exception and is more than accepted as part of the furniture. Eg we also use it as a drawing/art stool.