Jump to content

2052839955_Mobilephonebanner.jpg.a502a319d7033354d442937f2edd0c2c.jpg

New stellalyra dobsonian focus tube problem


Recommended Posts

Hi guys

I'm hoping you can help as I recieved this scope today from first light optics, and on trying the focuser it didn't move the focus tube when I turned the two speed focus nobs. 

The focus tube seems loose and lifts up and down but doesn't move when I turn the focus nobs. 

Even the focus nobs are loose and rattle. 

Am I missing something on set up or is this faulty as when I tip the scope over the focus tube just drops out. 

Iv tried phoning FLO but its answer machine, and tried emailing but it's an auto email. 

So am I stuck with a faulty scope until Monday, or is there a number where I could actually talk to a human. 

Obviously I'm a little upset as that's the planned astro weekend  lost now, and it seems they only open Monday to Friday. 

Any help would be much appreciated

Link to comment
Share on other sites

There should be two screws on the focuser between the knobs, one will adjust the pressure of the of the focuser wheel shaft on the focus drawtube, and the other one with lock the focus drawtube in place.

Tigthen the first one until the focus knobs make the drawtube move nicely.

It should say in the manual which screw is which.

Edited by CraigT82
Link to comment
Share on other sites

Oh my god, thanks for that Craig, I was so disappointed with this thinking it was faulty. 

There isn't any paperwork with it at all, which seems a little strange. 

Thanks again Craig, you've really cheered me up as that seems to have solved the problem. 

I'll start building the base now as I'v got an appointment with the moon and saturn at about 1am.

  • Like 1
Link to comment
Share on other sites

Oh my god, thanks for that Craig, I was so disappointed with this thinking it was faulty. 

There isn't any paperwork with it at all, which seems a little strange. 

Thanks again Craig, you've really cheered me up as that seems to have solved the problem. 

I'll start building the base now as I'v got an appointment with the moon and saturn at about 1am.

I don't know why a sheet with this simple instruction isn't in the box, it would save a lot of frustration and disappointment. 

I think like most, iv only used focus tubes that only have a locking nut, so it's a new experience for me. 

Thanks again Craig, such a simple solution, then again 2+2 is simple, but only if you know what 2 is. 

  • Like 1
Link to comment
Share on other sites

Aye, my 130pds didn't come with instructions either.  Well it came with a guide to telescopes but nothing specific to the scope.

The AZ5 did have instructions but they are pretty high level and not massively useful.  Fortunately these forums exist. 

  • Like 1
Link to comment
Share on other sites

My weekend would have been a total bust if Craig hadn't have told me what needed doing Ratlet. 

I had no idea, which a bit of paper saying this would solve. 

Iv got it up and out now and already lined the spotter scope up very easily with the way it is held in place, with a pigeon on an ariel about half a mile away. 

The colmination seems fine but I'll do a star test later to see. 

Now I'm over the disappointment I'm rather impressed with it up to now. Fingers crossed the clouds don't spoil things. 

  • Like 2
Link to comment
Share on other sites

13 minutes ago, col said:

My weekend would have been a total bust if Craig hadn't have told me what needed doing Ratlet. 

I had no idea, which a bit of paper saying this would solve. 

Iv got it up and out now and already lined the spotter scope up very easily with the way it is held in place, with a pigeon on an ariel about half a mile away. 

The colmination seems fine but I'll do a star test later to see. 

Now I'm over the disappointment I'm rather impressed with it up to now. Fingers crossed the clouds don't spoil things. 

Delighted for you chief 😊.

SGL is blessed with loads of people who have loads of experience.  What's better is they practically fall over each other to help.

Unfortunately they can't do anything about the clouds lol.

Clear skies!

  • Like 1
Link to comment
Share on other sites

4 hours ago, col said:

There isn't any paperwork with it at all, which seems a little strange. 

Pretty much the rule nowadays. I have an 8" of those, it's a really good scope. But at that price, there's bound to be flaws. I've dealt with a couple, check out this thread:

And for astrophotography with a crop sensor DSLR, the mirror has to be raised 20mm. No big thing, very easy mod on theese scopes. Clear Skies!

 

  • Like 1
Link to comment
Share on other sites

First light was marred by clouds,but I did get a clear spell at about  one. The moon was nice in the 30 mm eyepiece, and crisp with the 9mm, but as it’s my first time with a dob it was still strange to me.

I tried for Saturn with the 30mm eyepiece but was disappointed with what I saw, granted it’s only 40 x but I did expect a better image. So went to try the 9 mm eyepiece ,but alas the clouds filled the sky and I will have to wait to try that one on Saturn another time.

Now I’m not sure about the colimation, but it did seem ok. But when I did a star test I didn’t get concentric circles I got what looked like the spider and  middle circle inside the main circle with the three clips on the edge, so I’m unsure if it’s in colimation or not. Any advice on this would be great,as it could be why I was disappointed with Saturn being nearly unrecognisable without going in and out of focus until I could just make out the outer shape with the rings in a tiny dull image.

other than  Saturn though, I enjoyed the ease of being able to move and look with the smooth and easy gentle nudges.

I’d appreciate any opinion on the two supplied eyepieces too, as crisp as the moon was I’m thinking most scopes and eyepieces would be with the moon.

Was my expectation of Saturn and the 30 mm too high, as I’ve had great views with a 4 inch refracter of Saturn with a 25 mm wide eyepiece,and just expected better with the 8inch mirror and 30 mm eyepiece.

Anyway, that aside I’ve got a lot of time ahead to get more familiar with this new dob, as I’m off work for six weeks starting next Friday. And have some long early hours sessions planned.

Maybe it’s more suited to deep sky objects? Maybe it’s slightly out of collimation? Maybe the eyepieces aren’t great?

Im sure I’ll get to the bottom of these things soon enough, but any suggestions and help would be appreciated.

I’ll update when I have anything more

Cheers guys

 

 

  • Like 1
Link to comment
Share on other sites

I have a ten version of the scope you have, I didn't see where you may have mentioned a size.  The eyepieces that came with mine seem to be the same as what came with mine, and while they are alright, they are nothing special.   The GSO coma corrector will help the 2 inch out a bunch and make it usable.  

  • Like 1
Link to comment
Share on other sites

5 minutes ago, Mike Q said:

I have a ten version of the scope you have, I didn't see where you may have mentioned a size.  The eyepieces that came with mine seem to be the same as what came with mine, and while they are alright, they are nothing special.   The GSO coma corrector will help the 2 inch out a bunch and make it usable.  

Hi Mike ,Mine is an 8 inch, the 30mm is usable as it came with an extender to use with it. 

Link to comment
Share on other sites

8 hours ago, col said:

Hi Mike ,Mine is an 8 inch, the 30mm is usable as it came with an extender to use with it. 

I should probably said that differently.  The 30mm eyepiece that came with mine was a budget model 30 dollar eyepiece. It did not give the best image.  As planned we also had bought one "better" 1.25 and 2 inch eyepieces, about 100 bucks each.  The difference between the 2 eyepieces is night and day.  Later I added a coma corrector to clear up the bit of off axis coma.  Just for grins I grabbed the original 2 inch eyepiece and stuck it in and the image was definitely better with the corrector then without.

  • Like 1
Link to comment
Share on other sites

I'm going to try my own eyepeices when I get a chance, as I get better images from my 25 mm I'v had for 20 odd years in a 4 inch skywatcher startravel looking at saturn than I did last night with the supplied 30mm in an 8 inch dob. 

I won't go as far as a coma corrector, as iv always been happy with what I could see up to now. 

I'll also try the 30mm in my  Tal 100R to see what the difference might be in looking at saturn, as it's always been a cracking sight through that. 

I can't see the 8inch stellalyra being less able than a 4 inch refractor that's 25 years old. So I'm hoping it's just the supplied eyepieces causing the problem. 

Link to comment
Share on other sites

A 30mm eyepiece is not an eyepiece for Saturn. If you were pleased with a 25mm before you should be trying an eyepiece with more magnification, say a 10mm. This will give you 120x. I myself can go as high as 240x on Mars and Saturn (good seeing). The reason why you saw the central mirror was because you were trying a star test with a 30mm. Once again you need high magnification to conduct a star test. 
       HTH  

   

  • Like 2
Link to comment
Share on other sites

I have a collimation cap which shows everything looking concentric, I can even see the clips holding the mirror through it, so thought all seemed well, but it's the first time iv needed collimation so not really knowledgeable about it. I did wonder thanks bosun. I'll put a 6.3 mm in and try again when I can, will that size eyepeice do it? As it's the smallest I have. 

Link to comment
Share on other sites

Hi @col. For a star test, as @bosun21 said, you need higher magnification. You also need to only shift a small amount either side of focus. You are looking for diffraction rings, not an image of the secondary/vanes. The best article I've seen about star-testing a Newtonian is: https://www.astroasheville.org/wp-content/uploads/2013/09/No-Tools-Collimation.pdf

For Saturn, in my 8" dob, I find the best eyepiece for reasonable seeing, is an 8mm. This is 150x magnification. If the seeing is better, going up to a 6mm is possible.

For a star test, I look to Polaris (doesn't move much) and start at 12mm and see how much higher I can get. 4mm on a good night.

 

For the above - you need a range of eyepieces, obviously. Or a zoom/barlow combi. If you are looking for new EPs, I'd suggest a 12mm and 8mm and 2x barlow would be good for the coming planetary bonanza.

In an 8" dob (1200mm focal length):

12mm - 100x and 200x with barlow

8mm - 150x and 300x with barlow. The latter only good for nights of excellent seeing, but they do happen and if the gas giants are around, they'll take that magnification, esp Saturn.

Edited by Pixies
  • Like 2
Link to comment
Share on other sites

Thanks for that Pixies, I have a 6.3 a 10 and a 25, also a 2x cheap Barlow. But I'll definitely get another to fill the gap maybe the 12mm. 

Also iv been checking the collimation with a collimation cap, and after much back and forth I managed to get the tiny circle over the center, I think you can see in these two pics. 

I found tightening the locking nuts even just a little firmly put the tiny circle to the side of the centre. So I just lightly touched the locking nuts to lock which isn't very firm, but it's the only way I could keep the mirrors centre circle on the centre dot. 

Could you advise if that is good collimation or not? As I'm thinking it is but I'm new to collimation. 

Screenshot_20220717-163212_Gallery.jpg

Screenshot_20220717-163154_Gallery.jpg

Link to comment
Share on other sites

That 2nd pic looks pretty good. A star-test will confirm, but I'd be happy with that. The lock nuts can knock things out-of-whack. Some people don't use them at all. Others, like myself, use them as a final fine-tune; tightening them up just enough to take up the slack and checking the collimation still. One recommendation is to replace the springs around the main primary collimation knobs with much stiffer ones, then the locking screws aren't really needed!

 

  • Like 2
Link to comment
Share on other sites

Thanks Pixies that's good to hear, I'll be waiting patiently for clear skies again to get my own eyepieces tried now. 

I read something on here that the new springs are better than they were, so will see how it goes. But if it goes out of collimation too easily I'll do that. 

Thanks again Pixies. 

  • Thanks 1
Link to comment
Share on other sites

I just have to ask why the focuser tension wasn't adjusted properly at the factory.  Have they simply given up on imparting a good customer experience out of the box?

  • Like 1
Link to comment
Share on other sites

2 hours ago, Louis D said:

I just have to ask why the focuser tension wasn't adjusted properly at the factory.  Have they simply given up on imparting a good customer experience out of the box?

Out of the great many already sold this is the first time I’ve ever heard of the focuser tube falling out. But one is too many.

  • Like 1
Link to comment
Share on other sites

On 17/07/2022 at 23:23, bosun21 said:

Out of the great many already sold this is the first time I’ve ever heard of the focuser tube falling out. But one is too many.

Hi bosun21

It didn't actually fall out and leave the scope, it just fell out loose to its fullest position out, which was a bit of a surprise when it did, as the clack noise was a bit of a shock. 

  • Like 1
Link to comment
Share on other sites

If you are wanting instructions you can go to orion's website and find the skyline 8 inch.  There should be a down load there for the manual.    To my knowledge the only difference is the name on the side of the OTA

  • Like 1
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
 Share

×
×
  • 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.