Show Us Your Dobs

[Pixies]

1 minute ago, markse68 said:

i had similar but just removed it as I couldn’t be bothered to carry weights around with the scope and with the way my tube is held inside a sort of cradle it’s easier just to shift the tube up or down if balance is too far out to maintain set altitude. 

The Bresser 8" has very little range to move the scope down the rings. I'm already at the furthest limit and any further means I hit the base and can't get the scope pointing straight up.

It currently only suffers for targets below 30deg and because I have quite a heavy finder (I also like to have the alt bearing 'brakes' quite loose). But I'll have problems once I get some big 2" EPs, I'm sure. You can't tighten the bearings on the fly, like a Skywatcher dob. 

[John]

13 minutes ago, markse68 said:

i had similar but just removed it as I couldn’t be bothered to carry weights around with the scope and with the way my tube is held inside a sort of cradle it’s easier just to shift the tube up or down if balance is too far out to maintain set altitude. 

My dob is in tube rings so could be shifted up and down as well but that would not be enough and also the travel downwards I have is limited because of the way I have the scope setup for my eye height. I have a number of eyepieces that weigh well over 1kg so they do need counterbalancing when the scope is pointing below around 60 degrees. Its become second nature for me now

Whatever works for you though. I just thought I'd post the pic to show one fairly easy way to do it

 

[markse68]

26 minutes ago, John said:

My dob is in tube rings so could be shifted up and down as well but that would not be enough and also the travel downwards I have is limited because of the way I have the scope setup for my eye height. I have a number of eyepieces that weigh well over 1kg so they do need counterbalancing when the scope is pointing below around 60 degrees. Its become second nature for me now

Whatever works for you though. I just thought I'd post the pic to show one fairly easy way to do it

 

Sorry John, didn’t mean it to sound so contradictory 😬 I think if I were observing from home or somewhere more permanent then having the ease of just adding weights would be more convenient  for sure and of course for some scopes there just isn’t enough tube travel. As it happens I’ve also just removed my motor focuser as after initial enthusiasm for it waned I just resorted to manual focusing and it became dead weight 😂. So now my scope is rather bottom heavy so i have lots of rearward free travel to play with. does mean that at zenith i’m on tip toes though....🤦‍♂️ It’s a delicate balancing act!

Edited June 30, 2020 by markse68

[Barry-W-Fenner]

Not really a shot of the dob itself. More if a tease 🙂

Just thought I would post a pic of the Baader 1.25 to 2" click lock showing the build up. I know it was of interest to some other members, I'm looking at you @merlin100 🙂

The standard 2" adapter now sits in the focuser with the baader inserted, The click lock sits nice and flush and only increases the length by around 10mm. Unfortunately I haven't had chance to use it yet due to the poor weather so I cant comment on focus.

However changing eye pieces is an absolute breeze with this click lock. Straight in and about 1cm turn on the stalk your eye piece is locked in place centrally. So far I am really pleased with the quality of this purchase, I just need to test it out!

My short cheshire eye piece also arrived. I locked it into place with the click lock, Knowing it was central was very reassuring. When I looked through I could see that only two of the primary clips were present. A slight tweak to the secondary mirror followed by a larger tweak to the primary and the 300p is all collimated. Combining the cheshire with the click lock made this job so easy and I really look forward to seeing what the scope can do next time out!

 

Baz

 

Edited June 30, 2020 by Barry-W-Fenner

[Stu]

This is what I have on the 8” F8. It needs a fair bit of weight as I have a 60mm finder and Telrad on it. The mirror is pretty light and the tube long, so it probably needs more than say a 12”.

I can move the weight up and down just by loosening the clamp, or swap it for a lighter one or remove it altogether very easily as it just sits over a bolt (I have drilled holes in the weights). Works very well, mainly needed when viewing down low of course.

[John]

This thread is morphing into "show us a bit of your dob"

Interesting to see these different approaches though.

Meade used to stick a great lump of cast metal just behind the primary cell to counterbalance their dobs and newts. The problem with that was it increased the thermal mass around the mirror which slowed down cooling a lot

 

 

[russ]

I've had so many dobs down the years, starting in 1986 with a homemade 8.5" f5 in a hexagonal wooden tube. I sadly do not have a photo of that scope. It was a one off and a beautiful thing. I sold it to buy my first car a year later aged 17. Which meant i then had the car to get me to the dark sites but no scope to use. Doh!  

Anyway here's the dob's i do still have photos for. One is a cheat. It shows my Orion Optics 12" f4 on the EQ6 as i can't find a photo of it on the dob base....sorry. Dobs that i don't have pics are Skywatcher 150P, 200P and 250P solid tube dobs. Orion USA XT8 and XT10 (my fav). I love dobs!

Scopes below are:  Revelation 12, Meade Starfinder 12.5, SW 250PX Flextube and Orion Optics 12" f4. 

 

Edited June 30, 2020 by russ

[Ricochet]

4 hours ago, Stardaze said:

That's a nifty solution. I'm glad mine hasn't needed any counter balancing, yet. 

Loving the mods, shame I asked @Ricochet about his mods in another thread, would have been better suited here. I have pinched one of those ideas and am trying to find a B&Q store with the shed mate levelling feet, my local store didn't have any! My favoured spot in the garden isn't level, and whilst it's not absolutely detrimental to how the dob works of course, I just wanted a make it better,  so I have cut a circular piece of 18mm ply ready for said levelling feet. I also need to have a move around in the shed which is close to my little preferred spot. In the winter months, it will make a good place to have the EP case under cover and will also be where I store the dob overnight following a session, makes more sense than anywhere else. 

I got mine off eBay. None there now though, possibly as supplies have dried up during the lock down. 

[Dippy]

5 hours ago, Stardaze said:

That's a nifty solution. I'm glad mine hasn't needed any counter balancing, yet. 

Loving the mods, shame I asked @Ricochet about his mods in another thread, would have been better suited here. I have pinched one of those ideas and am trying to find a B&Q store with the shed mate levelling feet, my local store didn't have any! My favoured spot in the garden isn't level, and whilst it's not absolutely detrimental to how the dob works of course, I just wanted a make it better,  so I have cut a circular piece of 18mm ply ready for said levelling feet. I also need to have a move around in the shed which is close to my little preferred spot. In the winter months, it will make a good place to have the EP case under cover and will also be where I store the dob overnight following a session, makes more sense than anywhere else. 

 

14 hours ago, Pixies said:

Made some counterweights as per:

 

Thank you for sharing this nice idea. Would you mind if I ask whether the magnet is easy to slide during observation in the dark and if it stays in place when changing the angle of your telescope’s tube? I am asking because I found something similar in a web site, but like the one you have shared the picture of, it looks like normal magnets, not neodymium ones. So I am wondering are they strong enough to hold on to the tube. Thank you again for giving link and sharing this brilliant idea.

[markse68]

16 minutes ago, Dippy said:

 

Thank you for sharing this nice idea. Would you mind if I ask whether the magnet is easy to slide during observation in the dark and if it stays in place when changing the angle of your telescope’s tube? I am asking because I found something similar in a web site, but like the one you have shared the picture of, it looks like normal magnets, not neodymium ones. So I am wondering are they strong enough to hold on to the tube. Thank you again for giving link and sharing this brilliant idea.

you wouldn’t want a neodymium that size- it’d lift a car! (or cause you serious damage if you got on the wrong side of it!) Pot magnets like this increase the field strength by diverting the flux lines from the other pole round close to the centre pole- they’re probably just ferrite magnets like used in speakers i’d guess. Smaller ones can be alnico but a bit spendy. 

[Barry-W-Fenner]

3 hours ago, John said:

This thread is morphing into "show us a bit of your dob"

Interesting to see these different approaches though.

Meade used to stick a great lump of cast metal just behind the primary cell to counterbalance their dobs and newts. The problem with that was it increased the thermal mass around the mirror which slowed down cooling a lot

 

 

Do you know if Sky Watcher use a similar method to how Meade built there scopes? I ask as my 12" flex is very heavy at the base / Mirror. I have had the scope almost horizontal looking at the moon in its early phase this month and even then it still feels heavy at the rear.

I assumed this was all from the weight of the primary mirror, After you mentioned the above it wouldnt surprise me if there is a metal plate in there. If so I will have to factor into my cool down times!

Baz

[johninderby]

More money but Orion do magnetic dob counterweights.

https://www.amazon.co.uk/s?k=orion+magnetic&i=electronics&ref=nb_sb_noss

[John]

2 hours ago, Barry-W-Fenner said:

Do you know if Sky Watcher use a similar method to how Meade built there scopes? I ask as my 12" flex is very heavy at the base / Mirror. I have had the scope almost horizontal looking at the moon in its early phase this month and even then it still feels heavy at the rear.

 

No additional weight in the Skywatcher as far as I know.

 

 

[Pixies]

2 hours ago, Dippy said:

Thank you for sharing this nice idea. Would you mind if I ask whether the magnet is easy to slide during observation in the dark and if it stays in place when changing the angle of your telescope’s tube? I am asking because I found something similar in a web site, but like the one you have shared the picture of, it looks like normal magnets, not neodymium ones. So I am wondering are they strong enough to hold on to the tube. Thank you again for giving link and sharing this brilliant idea.

Hi,

I had to roughen the felt to make sure it wasn't too slippery, otherwise it didn't take much to start it sliding down the tube when vertical. I didn't want to use anything too sticky - like rubber - otherwise it might be tricky to move around. The magnet is powerful enough not to fall off, though. I'm careful to make sure I have a good grip when placing it up against the OTA, so that it doesn't suddenly slam into it. 

[Dippy]

5 hours ago, Pixies said:

Hi,

I had to roughen the felt to make sure it wasn't too slippery, otherwise it didn't take much to start it sliding down the tube when vertical. I didn't want to use anything too sticky - like rubber - otherwise it might be tricky to move around. The magnet is powerful enough not to fall off, though. I'm careful to make sure I have a good grip when placing it up against the OTA, so that it doesn't suddenly slam into it. 

Thank you! I am going to try this one out.

Edited June 30, 2020 by Dippy

[ian2]

Still too light and overcast to do much with my 300p flextube dob.

the scope is a auto rather than GOTO and I’ve bought a synscan Wifi adapter for it. With my iPhone and laptop it would align but then when going to the next object the az reading counts down then the degrees remaining value would jump up randomly and it would keep on going missing the target.
 

At first I thought it was a Wi-fi problem, dropping out etc but after going into the az controller housing I noticed that the az Reading on the app did not change if I turned the scope. Upon checking everything out I noticed the Allen grub screw fixing the encoder to the az bearing bolt was slack, hence allowing it to slip.
 

All I have to do now is wait until the permacloud goes away and it gets dark enough to see something.
 

I’ve also build a battery unit to avoid getting tangled up.

Edited July 7, 2020 by ian2
Spelling

[johninderby]

The new base for the Bresser 10” dob is finished. 👍🏻

Made from marine ply with a teak stain and Osmo oil finish. Built it a bit taller than the stock base. Bolted together with cast aluminium corner brackets.

Fitted a few large PTFE washers on the centre bolt to take a little weight off the Az bearing. The Az movement was good before but now it’s perfect as well as the Alt movement. The large castors make it possible to roll it over the lawn as well as the patio.

Over all very pleased with the end result. So much nicer than a melmine covered mdf base as well as being very durable. 🙂

Edited July 12, 2020 by johninderby

[Greymouser]

Superb @johninderby, I wish I had half your skill.

[John]

Nice job John. Proportions are now similar to my 12 inch

[IB20]

1 hour ago, johninderby said:

The new base for the Bresser 10” dob is finished. 👍🏻

That’s mint! Have you just knocked that up or is wood working your vocation?

 

 

[johninderby]

Strictly an amateur but enjoy making things. 🙂

Having recently finished renovating the house I bought a few years ago I now have loads of tools. All sorts of power tools so no problem knocking up a dob base. 😁

Edited July 12, 2020 by johninderby

[Pixies]

36 minutes ago, johninderby said:

Strictly an amateur but enjoy making things. 🙂

Having recently finished renovating the house I bought a few years ago I now have loads of tools. All sorts of power tools so no problem knocking up a dob base. 😁

Looks fab! How did you cut the curves for the Alt bearings?

[johninderby]

13 minutes ago, Pixies said:

Looks fab! How did you cut the curves for the Alt bearings?

Used the orignal panels to draw an outline on the ply. Used a jigsaw to cut about 1/4” oversize then clamped the original panel to the ply and used a router with a template bit to trim to the exact size.

[niallk]

Craftsmanship! 👍

@johninderby

[Moonshane]

I am sure I have probably had a few others but here's a selection:

My first dob, a 12" f5 OOUK. Loved it.

Made this one for a friend, my first home made project. 6" f5 on a home made stand.

Another home built unit. Based on a OOUK f5 made to pack down small for camping (glamping really) etc.

My 6" f11 OOUK on a home made equatorial platform. Sold the base etc now and swapped for a 1/10pv OTA only.

16" f4 OOUK with home made base. Stunning scope and still my biggest aperture.

12" f4 OOUK on home made base excellent for being so portable.

 

18" f4 made for a SGL friend and as far as I know still going strong.

Hope you enjoy my tour!