Stellarlyra 8" dobsonian, my thoughts so far.

[col]

I thought I'd give my 8" a review as there doesn't seem to be much about this size. 

After my own ignorance causing a worrying first hour with this scope on delivery, but was easily sorted after help from you guys, I'm liking it. 

After collimation the views are very nice indeed, though I'm still not getting a good star test which I'm thinking must be my own fault again. As saturn and jupiter were good although jupiter was very bright. I'm putting the lack of details down to bad seeing , but I'll report back on that. 

The only real issue on building the base was where the bearing washer went when connecting the base dish with the main body, due to the lack of instructions. 

It runs smoothly so I'm happy with it. 

Where the scope mounting blocks slip into the top of the mount, the tighteners hold the scope at any angle nicely. The only thing I noticed was when I tightened more than usual so the phone mount and phone weight didn't make  it creep down.

As I lifted or lowered the scope, the blocks in the slots moved, slightly rocking in the slots, instead of the scope only. Which was a strange feeling until I figured out what was happening. 

This isn't a fault, it's just something that will happen if you tighten the tensioners too much. 

The focus tube is very nice, even after my first encounter with it had me thinking that it was the work of the devil, especially with its fine adjustment too, which really helps getting the best focus. 

What I did find was sometimes swapping eyepieces it would reach maximum range of the focus tube but was just out of focus. Again this is probably a new user thing, as when I turned the focuser the other way then back again, low and behold it focused. So any advice on what was happening, I'm all ears guys. 

I never tried the 30 mm two inch without the extender so that wasn't an issue. 

My first try with the 30 was disappointing, but the following night it seemed fine. Again probably a new user thing. 

The 9mm was good too in my eyes, but I'm only used to plossles so can't say if that's a good thing or not. But I was happy with what I could see in the most. 

The 45 degree spotting scope was so easy to line up with the scope. 

I put a chimney cap in the distance to the centre of the eyepiece then checked the spotter, one turn on one screw and one turn on the other and it was bang on. 

Other than the failed star test, it's always in the back of my mind if I'm getting the best from this.

And wondering why I can't seem to get a good star test, I'm very happy with this. 

It's giving me better views than my 4 inch refractors, brighter and sharper. 

Iv been using a small table to put it on so it can clear the roof and trees a bit more, which  my refractors and tripods do with ease, but still will need an adjustable chair as I'm still leaning over for the planets and moon at the moment,which doesn't do my back any favours. 

I can't think of anything else right now, but I'm very happy with the views and look forward to the proper dark skies soon to come. 

I hope there's something in my review that helps any thoughts you might have about getting one of these. 

I'm very happy with it, I just wish I knew why I can't get a good star test, 😊

 

 

 

 

[cajen2]

Re the alt adjusters, it's worth trying the balance by loosening the side adjusters (graded scale) and achieve balance with your usual EP. Once tightened, fine adjustment can be made by sliding a magnet or two up and down (ensure they're padded to avoid scratches).  This way, having to tighten the black wheels too much shouldn't be a problem.

[Knighty2112]

Not sure if it does but does your front cover on your  scope have a smaller aperture that you can open to stop as much light getting down to the mirror? I find that large newts do better with Venus and Jupiter when stopped down like this, although generally I prefer to use my ‘fracs for planetary/Lunar observing. Failing that use a filter of some form on your EP’s to reduce the glare.

[col]

1 hour ago, cajen2 said:

Re the alt adjusters, it's worth trying the balance by loosening the side adjusters (graded scale) and achieve balance with your usual EP. Once tightened, fine adjustment can be made by sliding a magnet or two up and down (ensure they're padded to avoid scratches).  This way, having to tighten the black wheels too much shouldn't be a problem.

Thanks cajen2 sound good, I'm learning all the time from you guys. 

[col]

1 hour ago, Knighty2112 said:

Not sure if it does but does your front cover on your  scope have a smaller aperture that you can open to stop as much light getting down to the mirror? I find that large newts do better with Venus and Jupiter when stopped down like this, although generally I prefer to use my ‘fracs for planetary/Lunar observing. Failing that use a filter of some form on your EP’s to reduce the glare.

Unfortunately the dust cover has no aperture  reduction at all, it's just a very substantial plate that protects the inside of the tube very well. 

[Spile]

Use a cap to check your primary alignment https://astro.catshill.com/collimation-guide/

The StellaLyra is a well built Dob. Better value than the Skywatcher I own and had to spend money on upgrading to get an equivalent telescope to yours.

[col]

2 hours ago, Spile said:

Use a cap to check your primary alignment https://astro.catshill.com/collimation-guide/

The StellaLyra is a well built Dob. Better value than the Skywatcher I own and had to spend money on upgrading to get an equivalent telescope to yours.

Thanks for that Spile,

I have a cap and all seems well , but it is the first scope I've had to check collimation.

[col]

This is how iv got it Spile. 

Edited August 12, 2022 by col

[dweller25]

@col Nice writeup 👍

Your collimation is close but may need tweaking slightly - but it could be a line up issue with the camera ?

I am finding seeing due to the warm weather is poor before midnight - stars look fuzzy at focus - it will improve when the weather cools and the skies become more stable.

Try to observe on grass as hot concrete gives off thermals for hours.
 

 

Edited August 14, 2022 by dweller25

[Mr Spock]

I collimate my 12" StellaLyra before each session. Even slightly out will spoil the image.

[col]

Thanks dweller 25, I'll stay off the paving now as luckily we do have a lawn also. 

Mr Spock, would you say the collimation is way out in that picture? I don't really know how close it needs to be, or if there's an allowance that might not make much difference to the view? 

But I'll keep trying, as once I get adjusting the secondary sometimes it just won't go where I want it 😂

[Mr Spock]

1 hour ago, col said:

Mr Spock, would you say the collimation is way out in that picture?

Yes, needs a tweak  When it's spot on, fine detail will snap into focus instead of being blurred.

[col]

21 minutes ago, Mr Spock said:

Yes, needs a tweak  When it's spot on, fine detail will snap into focus instead of being blurred.

Ok sounds good, I'll get to it and try and get it bang on, thanks Mr Spock. 

[col]

4 hours ago, Mr Spock said:

I collimate my 12" StellaLyra before each session. Even slightly out will spoil the image.

Iv just got a Stellarlyra 2 inch 2x Barlow and an 18mm  kitakaru Eye piece too, hopefully here by Tuesday.

Iv read good things about these, looking forward to using them. 

Edit to add Iv got the Esterion Variseat coming too, the most important accessory for me right now 😁

Edited August 14, 2022 by col

[Spile]

On 13/08/2022 at 00:17, col said:

This is how iv got it Spile. 

You can see the secondary error in part 2 of https://astro.catshill.com/collimation-guide/

The dark offset secondary reflection should be offset toward the primary mirror. 

Take another photo with a piece of coloured paper behind the focus tube as explained in my guide and ensure that you show the complete circumference of the bottom edge of the focus tube. See https://astro.catshill.com/through-the-eyepiece-tube/

Edited August 15, 2022 by Spile

[col]

15 hours ago, Spile said:

You can see the secondary error in part 2 of https://astro.catshill.com/collimation-guide/

The dark offset secondary reflection should be offset toward the primary mirror. 

Take another photo with a piece of coloured paper behind the focus tube as explained in my guide and ensure that you show the complete circumference of the bottom edge of the focus tube. See https://astro.catshill.com/through-the-eyepiece-tube/

I don't fully understand, but the reflection of the collimation cap in the eyepeice, does that have to be central? As it shows off centre in the pictures of the instructions? 

Here's where I am at the moment. 

[col]

[col]

Now I'm a little further over, so closer to Central I think? 

[col]

So do I adjust the primary mirror centre circle to the collimation cap centre spot in the eye peice, even though its slightly to the left. 

[Mr Spock]

Try and get the dot in the centre of the circle 👍

[col]

1 hour ago, Mr Spock said:

Try and get the dot in the centre of the circle 👍

Iv been trying for an hour, got a sweat on 😂

It goes everywhere but closer to the centre.  

I seem to get to the maximum adjustment and it won't go any further, as in the adjustment thumb screw is tight and would need what feels like a lot of pressure to turn it some more. 

[col]

I dare not turn another screw in case it jumps to the other side of the circle 😂 

Is this good enough to be well collimation? 

[col]

[Spile]

The offset reflection is looking good now. I’ll superimpose circles over it tomorrow to confirm.

The three outer bolts interact with one another and that is why you cannot tighten one without loosing one of the others and/or the central screw.

I would hang fire for now.

Edited August 15, 2022 by Spile

[Spile]

You are getting closer. There now only a small amount of offset error A≠B which I would ignore but I would fix the rotation/tilt error (c ≠ d /e ≠ f) so that the edge of the secondary and reflected edge of the primary end up as per my interpretation below.

Once you have got this as good as you can (a Cheshire Eyepiece and Sight Tube is recommended) then adjust the primary mirror as per https://astro.catshill.com/collimation-guide This is the most important stage but also the easiest especially if you have someone to help you.

Edited August 16, 2022 by Spile