12" Dob - essential 'tweaks'

[Mr Spock]

I'm so pleased with this StellaLyra 12" Dob. The optics are far beyond what I would have expected at this price. I may well have just gotten lucky but they are better than many premium scopes I've looked through. I've already had several nights on the moon with my best ever views. Roll on Jupiter and Mars (Saturn is still a bit low here), I can't wait to see you 

Like anything though it's made to a price, but there are are a few tweaks and mods that can make things a little better.

Focuser collimation.
It was just never right. Adjusting the secondary didn't fix things and the addition of a concentre collimator showed me it was the focuser. Tried various thickness shims until it was right. 

Like most Newts, the focuser and finders give it a lop-sided balance. Adding a 2.5Kg counterweight on the opposite side using 2" industrial Velcro fixed this. The alt just floats! Plus I can move the counterweight depending on what eyepieces I have attached.

The other thing that floats is the az, thanks to a full size lazy Susan bearing. The supplied half size roller bearing is flimsy and wobbly. This cures that. Expensive, but worth it.

The cage itself had a lot of flex. A couple of braces help - it's not perfect though and may need a rebuild with thick, marine ply.

And finally, something to stand it on. Some feet to prevent it standing on the collimation bolts when upright.

You can't see them here, but Bob's Knobs on the secondary and uprated springs on the primary really help with adjusting and maintaining collimation. The original springs were so weak the primary just clunked and groaned when trying to collimate; collimation changed every time the scope moved around too which was frustrating. All solid now.

All in all, it's now a great scope to use 👍

 

[Carbon Brush]

Thanks for posting.
It is encouraging that your tweaks are all low cost and relatively easy for most people to carry out.

[rl]

It's a common experience buying Newtonians that what you actually get is a "project" that requires you to make the detail engineering decisions on how to manage balance and collimation consistency. Unless you buy one of the really top end offerings there is always something that can be improved upon with them, usually at minimal cost making you wonder why they don't just do it in the first place. Every Newt I've ever owned has had some sort of mod done to it for some sort of extra to be bolted on or moved. 

I've engineered in quite a few improvements on even expensive OO carbon fibre newts. A simple one is adding feet to the mirror end just so you can stand up the OTA without it sitting on the collimation bolts....often really simple things can really enhance the ownership experience.

[Second Time Around]

My first OOUK Dob came with carrying handles fitted on to the base by the previous owner.  I copied that on the second one I bought.

[Guest]

1 hour ago, Second Time Around said:

My first OOUK Dob came with carrying handles fitted on to the base by the previous owner.  I copied that on the second one I bought.

I bought handles for my ten inch.  Can't figure out why they don't come with them.

[NGC 1502]

The start of a great thread👍
 

The above says it all.  Dobs are almost always a project scope.  That’s absolutely not to put them down, for me it’s all part of the fun, the tweaks and mods that make a good scope into a great scope.

Collimation springs- when choosing new ones if you can compress them with your fingers they’re too weak.  Big Dobs have used car engine valve springs for that purpose.  Probably ones from a small car or motorbike engine would be good.

If the mount is made from compressed particle board the raw edges can be sealed with a couple of coats of PVA (wood glue) allowed to dry before assembly.  Stops water ingress on those cold damp nights.

 

Edited June 6, 2022 by NGC 1502

[Guest]

On 05/06/2022 at 13:11, Mr Spock said:

I'm so pleased with this StellaLyra 12" Dob. The optics are far beyond what I would have expected at this price. I may well have just gotten lucky but they are better than many premium scopes I've looked through. I've already had several nights on the moon with my best ever views. Roll on Jupiter and Mars (Saturn is still a bit low here), I can't wait to see you 

Like anything though it's made to a price, but there are are a few tweaks and mods that can make things a little better.

Focuser collimation.
It was just never right. Adjusting the secondary didn't fix things and the addition of a concentre collimator showed me it was the focuser. Tried various thickness shims until it was right. 

Like most Newts, the focuser and finders give it a lop-sided balance. Adding a 2.5Kg counterweight on the opposite side using 2" industrial Velcro fixed this. The alt just floats! Plus I can move the counterweight depending on what eyepieces I have attached.

The other thing that floats is the az, thanks to a full size lazy Susan bearing. The supplied half size roller bearing is flimsy and wobbly. This cures that. Expensive, but worth it.

The cage itself had a lot of flex. A couple of braces help - it's not perfect though and may need a rebuild with thick, marine ply.

And finally, something to stand it on. Some feet to prevent it standing on the collimation bolts when upright.

You can't see them here, but Bob's Knobs on the secondary and uprated springs on the primary really help with adjusting and maintaining collimation. The original springs were so weak the primary just clunked and groaned when trying to collimate; collimation changed every time the scope moved around too which was frustrating. All solid now.

All in all, it's now a great scope to use 👍

 

If you happen to have a picture of the full sized lazy Susan bearing I wouldn't mind seeing it.

Edited July 11, 2022 by Mike Q

[Mr Spock]

5 hours ago, Mike Q said:

If you happen to have a picture of the full sized lazy Susan bearing I wouldn't wind seeing it.

[Guest]

4 hours ago, Mr Spock said:

Thank you.  And just how wide is that across and did you have to change anything else due to that being a much heavier and thicker bearing 

Edited July 11, 2022 by Mike Q

[tony4563]

My mods to my 12" GSO Solid Tube Revelation Dobsonian:

 

Replaced the Primary Springs

Bobs Knobs for Collimating the Secondary

Fully Flocked the Tube

Setting Circle / Inclinometer To Find Targets

2 x Velcro Handles for Easier Transportation

12" Vinyl Record Underneath the Lazy Susan to Ease Friction

Black Basic Foam Mouse Mat to Protect Tube Banging Base when Vertical

Three Black Plastic Feet to Raise Base Off The Ground

Large Shower Cap at Bottom of Scope to Prevent Spiders etc

Full TeleGizmo Cover 

 

To Do:

2 Handles for the Base

 

 

Glad you like the scope Michael.

I love mine. Brilliant bang for the buck!

 

 

 

 

Edited July 12, 2022 by tony4563

[Mr Spock]

On 11/07/2022 at 10:18, Mike Q said:

And just how wide is that across and did you have to change anything else due to that being a much heavier and thicker bearing 

600mm. Nothing else changed. The centre bolt is long enough to accommodate the extra depth.