Jump to content

Narrowband

Upgraded springs


Recommended Posts

I have noticed that the primary in my 10" moves nearly every time it's moved so I want to upgrade the springs can someone point me in the right direction for some please. 

It's the 10" Celestron starsense 

Thank you in advance. 

Link to comment
Share on other sites

Bobs Knobs has springs for that I believe.  I think FLO even carries them. 

Another option would be to add a Bellville washer to the spring.  Instant custom tailoring in length and cost a little bit of nothing. 

I suppose you could even completely replace the spring with a stack of Bellville washers, after all they really are just a spring that is shaped like a washer 

Edited by Mike Q
Link to comment
Share on other sites

I couldn't find the springs on FLO so bought them from RVO for my 8". For my 12" I bought heavier springs from eBay in a pack of 10 and ended up fitting them on both. The collimation holds great now even after a journey on the sack trolley.

Edited by bosun21
Link to comment
Share on other sites

Although they don't cost much and can be fitted relatively easily, when I see threads like this I can't help asking myself why such a basic upgrade is necessary to a simple component that is critical to the successful optical performance of an instrument ?

With GSO newtonians (and maybe other brands) the need to upgrade the sub-par stock primary springs has been documented for many years by reviewers and yet we are still having to do it.

Collimation is one of the big issues that can put people off newtonians - I would have hoped that by now manufacturers could at least install stable support for the primary so that, once achieved, collimation is maintained in a reasonable fashion. 

This isn't a rant, just a rather puzzled and slightly exasperated comment 🤔

In most other respects these scopes are excellent of course 🙂

 

 

  • Like 5
Link to comment
Share on other sites

What pickles my brain is that they use cheap spring then they add lock screws to help it keep collimation.  From my understanding, with decent springs you don't need to lock screws.  Surely the springs cost less than an extra 3 bolts?  Or am I wrong on that?

  • Like 2
Link to comment
Share on other sites

13 minutes ago, John said:

Although they don't cost much and can be fitted relatively easily, when I see threads like this I can't help asking myself why such a basic upgrade is necessary to a simple component that is critical to the successful optical performance of an instrument ?

With GSO newtonians (and maybe other brands) the need to upgrade the sub-par stock primary springs has been documented for many years by reviewers and yet we are still having to do it.

Collimation is one of the big issues that can put people off newtonians - I would have hoped that by now manufacturers could at least install stable support for the primary so that, once achieved, collimation is maintained in a reasonable fashion. 

This isn't a rant, just a rather puzzled and slightly exasperated comment 🤔

In most other respects these scopes are excellent of course 🙂

 

 

I had this exact discussion with Orion USA a while back.  I told them if they used thumbscrews on the secondary and better springs in the primary they would be well ahead of the game, as those two parts are upgraded almost immediately. 

Link to comment
Share on other sites

18 minutes ago, bosun21 said:

Better with both IMO. I use the lock screws to complete the fine final adjustments to collimating the primary mirror.

I do the same thing. 

Link to comment
Share on other sites

2 hours ago, bosun21 said:

You absolute star just about to order 10 as that is the packs they come in cannot grumble for a fiver thank you for posting the link and specs.

  • Like 1
Link to comment
Share on other sites

2 hours ago, bosun21 said:

Better with both IMO. I use the lock screws to complete the fine final adjustments to collimating the primary mirror.

I only used the lock screws on my 12 inch OO dob when it went for a car journey. Otherwise, it's simple cell held collimation well. 

 

Link to comment
Share on other sites

1 minute ago, John said:

I only used the lock screws on my 12 inch OO dob when it went for a car journey. Otherwise, it's simple cell held collimation well. 

 

I use them all the time as I have to use the sack barrow to maneuver the 12” outside over a couple of doorstops. The lock screws keeps the mirror collimated for me. I check the collimation both primary and secondary before each observing session. If any tweaks are needed it’s the primary mirror 99% of the time which can be sorted with slight tweaks of the locking screws. My secondary holds its position very well.

  • Like 2
Link to comment
Share on other sites

8 hours ago, Ratlet said:

What pickles my brain is that they use cheap spring then they add lock screws to help it keep collimation.  From my understanding, with decent springs you don't need to lock screws.  Surely the springs cost less than an extra 3 bolts?  Or am I wrong on that?

Correct. With good springs, the lock bolts can be removed.

I agree with the posts above that commercial telescopes should be fitted with decent springs from the factory. 

  • Like 2
Link to comment
Share on other sites

I replaced mine on the 12" with upgraded springs from Bob's Knobs. They work perfectly. Before you could hear them creak and groan as the mirror moved around; collimation didn't hold at all. Now it does. The last time I got the 12" out it didn't need adjusting at all.

Don't need the bolts at all :smile:

As has been said, I don't know why these springs, and secondary bolts (I fitted Bob's Knobs there too) aren't fitted as standard. It's such a small difference in cost but a huge difference in performance.

  • Like 2
Link to comment
Share on other sites

In my 8" skywatcher dob the lock bolts were removed when the new springs were installed.

Originally, my 12" truss dob had heavy duty springs and they held collimation well. That mirror cell was replaced by a new one due to other issues and the latter does not have springs at all. Collimation is done via rotation of bolts which push up / pull down the mirror.

Old mirror cell with springs:

IMG_20200201_121514.thumb.jpg.ed9169ff93ebda5bb38ec4e69f95d2f8.jpg

 

New mirror cell during telescope making:

image.thumb.jpg.10e9ffd6d4ac28127340998ba6d85def.jpg

IMG_20220430_124706.thumb.jpg.8925ae8d601f8d99bdcdad5ff0e5160e.jpg

 

Same cell design (but more supporting points) for my 16":

IMG_20200809_124656.thumb.jpg.47c4852301ce639f73f1f2a43d3ace13.jpg

image.thumb.jpg.ca7c5cd431986e026eb9de8060f784f2.jpg

  • Like 2
Link to comment
Share on other sites

This is from a review of the GSO made Meade Lightbridge 12 inch dated June 2006, by the late Tom Trusock:

"....I’ve owned truss dobs for many years now, and collimation is typically a 5 minute process when everything works well. The Meade took me about an hour to get acceptable collimation the first time, and while it got easier with practice, I never did get down to the 5 minute mark. A close examination of the workings revealed why. Ultimately I discovered that the springs Meade uses simply weren’t strong enough to correctly support the weight of the 12” mirror. Since it wasn’t properly supported, it didn’t move as freely in the cell as it should have, collimation was a real pain, and exacting collimation was nearly impossible. Frankly, I’m not sure that I ever got to see the best images this mirror was capable of producing.

New bolts and springs would be an improvement....."

 

 

 

  • Thanks 1
Link to comment
Share on other sites

First thing I did was to change the secondary grub screws to thumb ones I have replaced the red dot as I needed to be a contortionist to look through, with my back not good.

I have a Telrad and a 4" riser much easier, kindly sent to me by Maurice (banjaxed).

I went to the Brecon Beacons from the 4th to the 8th of May forecast was lousy but it changed and Saturday night was clear I set up and just checked the collimation I had previously collimated it its was out again that's when I decided to upgrade the springs. I have put a lazy Susan on it and its much much easier to turn and hold position now next I will be flocking it.  

I do wish though that the app could have Sky Safari incorporated in it.  The app does not give you a great amount of objects once you have been through the list you have to search stuff out, I dont mind researching and writing objects down but with Sky Safari you can do a list in that and go through it. 

Anyway springs will be here between the 26th of May and the 5th of June I may get the flocking material as I will have the cell out.

  • Like 1
Link to comment
Share on other sites

44 minutes ago, wookie1965 said:

I have put a lazy Susan on it and its much much easier to turn and hold position now next I will be flocking it. 

Same here - a full sized bearing. That and strengthening the base has given me a scope that is a joy to use. 

I need to flock it too, but the size of the tube is putting me off :sad2:

  • Like 1
Link to comment
Share on other sites

3 minutes ago, Mr Spock said:

Same here - a full sized bearing. That and strengthening the base has given me a scope that is a joy to use. 

I need to flock it too, but the size of the tube is putting me off :sad2:

When I had my 12 inch dob, I flocked the area of the tube opposite the focuser (an A4 sized area) and a strip of the inside of the tube for about 10 inches above the primary surface. Possibly not quite as good as a "full flocking" but it seemed to make a small difference to light scatter and if nothing else gave me some assurance that I had done "something" positive 🙂

  • Like 1
Link to comment
Share on other sites

15 minutes ago, Mr Spock said:

Same here - a full sized bearing. That and strengthening the base has given me a scope that is a joy to use. 

I need to flock it too, but the size of the tube is putting me off :sad2:

I completely flocked my SkyWatcher 8” Dob. But I would have thought that bigger would be easier. For my 8” I found it a bit “tight”. Flexible wrist are a bonus, but even so I got wrist pain doing it :(

However, definitely worth the effort and overall it was far easier than I was led to believe! 

  • Like 2
Link to comment
Share on other sites

I will be pulling my mirror for cleaning eventually, i may consider flocking it at that time.  I know one guy that has done it, he isnt convinced that doing the whole tube was needed.  

Link to comment
Share on other sites

The primary cell of my Skywatcher 8” Dob has rubber grommets in place of springs plus locking screws. I’ve heard a few people moan about these grommets (why aren't they springs, it’s just cheap, that kind of thing) but I haven’t found them to be a problem and they work for me.

But at first I struggled to get these to lock the primary in a satisfactory manner. Then, someone on here, can’t remember who it was, mentioned using the locking screws as fine adjustment just as you are getting to the locking stage. If you aren’t careful locking down the locking screws can move the primary a little which is frustrating.

In order to lock the primary the trick here is to move the locking screws just so they “touch” the primary. Then slightly adjust adjust the associated collimating screw. Go back and forth between each screw until everything is tight, but not too tight. The screws operate together in a kind of push/pull fashion. Once I understood this and got the knack - issues solved.

Now, I check the collimation every session and I last made adjustments over a year ago. But I haven’t needed ti adjust anything at all. Sure, I’m only moving the telescope from house to back garden but the primary is properly locked. And no springs required. Proper springs could be ‘better’ but it works well so why bother.

I also have a small Skywatcher 4.5” reflector. Now this does have springs and (more importantly) proper ‘Bobs Knobs’ type thumb screws on the primary cell. Why the ‘cheap’ small reflector includes these but the 8” doesn’t is a bit of a mystery. Even with the springs I followed the same procedure to lock the primary as I do on the 8”. Last summer I took this telescope on an aircraft to a dark site. After the 4 hrs in a car (2 hours on winding mountain roads), going through customs, 4 hrs in a an aircraft, dragging the case + telescope on cobbled streets, 35 mins in a ferry… I was very surprised to find the collimation hadn’t budged and was still spot on. Same with the return journey where I wasn’t as careful. Of course this is a small telescope with a small mirror but even so.

  • Like 1
Link to comment
Share on other sites

42 minutes ago, Mike Q said:

I will be pulling my mirror for cleaning eventually, i may consider flocking it at that time.  I know one guy that has done it, he isnt convinced that doing the whole tube was needed.  

The only way to be sure would be to compare the same telescopes (one fully flocked the other not) side by side on the same night. As the cost difference was minimal I decided to do the whole lot. But I also flocked the inside of the draw tube, painted the outside of the draw tube, painted the back & edge of the secondary, replaced bolts & nuts with mat black versions. 

For DSO I don’t think it makes much if any noticeable improvement. But for bright & low contrast observations like the planets it certainly does. The difference on Jupiter and especially Mars, where you are looking for subtle differences in colour contrast was very obvious. And of course I painted and flocked at the same time so hard to know exactly what’s making the improvements.

Edited by PeterStudz
  • Like 1
Link to comment
Share on other sites

23 minutes ago, PeterStudz said:

The only way to be sure would be to compare the same telescopes (one fully flocked the other not) side by side on the same night. As the cost difference was minimal I decided to do the whole lot. But I also flocked the inside of the draw tube, painted the outside of the draw tube, painted the back & edge of the secondary, replaced bolts & nuts with mat black versions. 

For DSO I don’t think it makes much if any noticeable improvement. But for low contrast observations like the planets it certainly does. The difference on Jupiter and especially Mars, where you are looking for subtle differences in colour contrast was very obvious. And of course I painted and flocked at the same time so hard to know exactly what’s making the improvements.

You can't even really make that comparison because the two scopes arent exactly the same.  If i end up doing it i will probably just paint the area opposite the focuser first and see what that does.  Plus, and this may be a non-issue, i don't like the thought of a fuzzy material possibly shedding onto my primary.  

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.