Stellarlyra 8" dobsonian, my thoughts so far.

[col]

Thanks Spile

I'll have a go at it later. 

That's really helpful, I would have happily carried on with the bullseye target set up thinking it was collimated when it wasn't. 

Iv learned more on here from you guys than I could ever have. 

It's much appreciated Spile, I'm looking forward to looking up more so now. 

[Spile]

9 hours ago, col said:

Thanks Spile

I'll have a go at it later. 

That's really helpful, I would have happily carried on with the bullseye target set up thinking it was collimated when it wasn't. 

Iv learned more on here from you guys than I could ever have. 

It's much appreciated Spile, I'm looking forward to looking up more so now. 

Yes indeed. Enjoy some great observing.

[Moonshane]

One thing I learned a long time ago is that you should never miss a planned observing session due to feeling that your collimation is not bang on and waste time twiddling in the dark. Collimation is important (as above, especially the final dot in the circle primary adjustment) but if it's off a little you will still see almost the same stuff and atmosphere or your neighbour's roof/chimney or a street lamp will probably have more of an effect. I only check secondary alignment every now and again. Once set it takes some moving unless it's a truss dob.

In truth if you practice collimation when the pressure is off - in the daytime, with a brew, it will click after a short time and then you will sort the primary collimation at least in 10 seconds or so.

Keep going, you have a great scope.

[col]

Iv been trying for a while, and no matter what I do I can't seem to get it just that tiny bit more centred. 

This is where I've decided to stop today. One turn of the screw leads to it further away and a few more turns to get it back. I'v tried that many times I'v had enough this time 😂 I'm hoping you guys say it's close enough. 😊

[Moonshane]

Could you send a pic of the primary collimation screws?

[col]

There you go Moonshane. 

[Moonshane]

OK so as I see the pics, the black ones have a spring. These are the collimation knobs. The screws pull and the spring pushes. The white ones are designed to hold the position and should only be done up with very light even pressure once collimation is achieved. I don't have these locking screws on my scopes.

My recommendation is as follows. Loosen the white ones all the way off until well away from the cell. Then adjust the black ones until your primary circle is evenly centered over the collimation eyepiece hole. 

Then take the white ones back in until they only just touch the cell. Check the collimation again as this last bit might move it slightly. If so back them off slightly. I doubt they are beneficial unless I am misunderstanding the cell construction.

This may help too.

 

Edited August 17, 2022 by Moonshane

[col]

Hi Moonshane

Thanks for that, that's exactly how I did it. 

Going on the picture I posted would you say that's collimated? 

 

[col]

Tonight's observing was a little disappointing as the seeing was not good. But I was able to look at Saturn through a number of eyepieces. Though even Saturn seemed that bright it looked over exsposed. 

I'm wondering if this is due to the adjustments I've made in the collimation? 

The new stellalyra 2" 2x Barlow  wasn't that much different to my normal 2x Barlow, but I'll have to wait for good seeing to make a real comparison, though there did seem to be a very slight improvement, but it was difficult to say with any certainty this time. 

Similar with the stellarlyra 18mm katakaru, it would be unfair to compare with the very bright Saturn and seeing, but it performed similarly. 

I have to mention the observing chair I also recieved today, the Asterian Variseat. 

What a great seat this is, strongly made, folds flat and has more than enough adjustments in height. 

My back never ached once  while I was out tonight,as normally I have to stand up straight and stretch it out regularly. 

I can't say enough about this chair, other than it's great. 

 

According to clearoutside.com the next clear sky is Thursday, I hope it doesn't change as I'm already looking forward to getting out again. 

But this time I'm going to christen the chair properly with a good relaxed visual night. I might plan a couple of targets, but then again I might just scan and have a pot luck sort of night too, so fingers crossed it's clear skies. 

 

[Moonshane]

7 hours ago, col said:

Hi Moonshane

Thanks for that, that's exactly how I did it. 

Going on the picture I posted would you say that's collimated? 

 

Not quite, the dot needs to be perfectly concentric with the circle.

That said, this won't be the reason for an 'over-exposed' Saturn or Jupiter. That will be either seeing related or just getting your eye in. Sometimes (always) when looking at bright planets you need to stare intently for a minute or so and then detail will eventually begin to emerge. The atmosphere/seeing makes detail on planets go something like, fuzzy, fuzzy, sharper, wow!  This is normal and it's on rare nights when planetary detail is stable and sharp for any length of time. Good luck with the collimation. 

[col]

Thanks Moonshane

I'll keep at it, and your advice of looking at a planet for a while is something I hadn't thought about, but I now know. Cheers for that, I'm taking all you guys advice and tips in and learning something all the time. 

I'll get the collimation right, eventually I'm sure, but if it wasn't for this forum I'd have been not quite collimated but believing I was. 

But the improvement in what I can see with this Stellalyra 8"dob, even when I wasn't collimated properly, has really upped my enjoyment of looking up. 

It was that much better than anything else I've got it had me thinking it was collimated, it's that good in the extra detail. 

Roll on good seeing conditions. 

[col]

Iv only turned the locking screws lightly until they just touch so as not to move the circle over the dot. 

This is what iv managed up to now. 

I'll keep having a go though. 

[Moonshane]

You're a bit closer every time. Eventually you'll see it centralised just like the feeling when the GRS first appears before your eyes 😁

[col]

I'll get there, and can't wait to be able to see the GRS😁 One thing I did notice last night with the stellalyra 2" 2x Barlow, I had to move the Barlow a little out of the focus tube to get focus on some eyepeices. 

It's not an issue, I just didn't expect it. 

[Mr Spock]

12 minutes ago, col said:

One thing I did notice last night with the stellalyra 2" 2x Barlow, I had to move the Barlow a little out of the focus tube to get focus on some eyepeices. 

It's not an issue, I just didn't expect it. 

Your scope should have come with an extension tube - have you tried that?

[col]

4 hours ago, Mr Spock said:

Your scope should have come with an extension tube - have you tried that?

Yeah for the 2" 30mm, I tried it and sometimes it was too much, again it's a new user thing with me. 

I'm sure I'll get used to which eye piece needs the extension. But just pulling the Barlow out a little was no problem and easy enough to do if needed. 

So should I use the extension with the 2" Barlow as the normal thing to do Mr Spock? 

Edited August 18, 2022 by col

[Mr Spock]

2 minutes ago, col said:

So should I use the extension with the 2" Barlow as the normal thing to do Mr Spock?

You can, or do what you have been doing. As long as it works 

Strangely my 12" doesn't need the extension. It works with any of my Barlows, and with my 2" eyepiece.

[Moonshane]

3 hours ago, col said:

Yeah for the 2" 30mm, I tried it and sometimes it was too much, again it's a new user thing with me. 

I'm sure I'll get used to which eye piece needs the extension. But just pulling the Barlow out a little was no problem and easy enough to do if needed. 

So should I use the extension with the 2" Barlow as the normal thing to do Mr Spock? 

That's the experimentalist dob owner in you coming out 🤣. We all like tweaking. That's tweaking NOT twerking.

[bosun21]

I can reach focus comfortably with all my 1.25” eyepieces in my Stella Lyra 8” dobsonian, however I sometimes need the extension piece for some 2” eyepieces. Although I tend to just pull the eyepiece out a couple of mm rather than have to mess around.

Edited August 18, 2022 by bosun21
Typo

[col]

7 minutes ago, bosun21 said:

I can reach focus comfortably with all my 1.25” eyepieces in my Stella Lyra 8” dobsonian, however I sometimes need the extension piece for some 2” eyepieces.

I wasn’t paying attention to which eyepieces needed extending with,but I’m guessing there’s a line you cross, be it high to low or low to high power where the extension is needed after a certain mm eyepiece? But this is with the 2” Barlow if I remember correctly?
Ill try to remember next time to see if I can take note .

Edited August 18, 2022 by col

[col]

4 hours ago, Mr Spock said:

You can, or do what you have been doing. As long as it works 

Strangely my 12" doesn't need the extension. It works with any of my Barlows, and with my 2" eyepiece.

I only had to extend while I was using the 2” Barlow and swapping 1.25 eyepieces. With hindsight I would have made a note of which ones.

But no extension is needed with all my 1.25 eyepieces even with the 1.25” Barlow in an 8” Dob.

The 2” 30 I use the extension every time

[col]

Not long in from tonight's observing, and after realising something that made a big difference, I was actually able to do a start test and get the results I was hoping for. 

The star test was with a star  not far from straight up, and with the 9mm stellalyra in the stellalyra 2x 2" Barlow. After trying so many times and trying to figure out why I can't do a star test, I saw on and off with good seeing coming and going those several concentric circles like a bullseye target. I nearly shouted "Get iiiiiin" , but it was nearly midnight and controlled myself 😁

The outer ring was pretty jagged, but all the internal rings looked concentric. 

Now your probably wondering what I realised to help me in getting this result. 

Well it's a rather simple solution of using my left eye instead of my right. 

I have a habit of using my right eye as I also do air rifle 10 metre Olympic target shooting. And I'm right handed with the rifle and pistol. 

Breaking this habit is going to be difficult, but I also have a slight astigmatism in my right eye, which has been causing the problem of not being able to do a star test. 

It was a brilliant moment realising the problem and seeing the concentric circles. 

Anyway, after the star test I wasn't intending doing much observing as I was expecting cloud, but it was still clear so I turned the scope to jupiter. 

After spending some time, maybe five to ten minutes trying to get the focus as best as I could, I could see two solid orangey bands. No other detail was visible with the brightness of jupiter, but it did look very nice. Roll on good seeing. 

Before the star test I had a quick look at saturn, as it was on its way to going behind the trees so spent ten minutes enjoying the view. I could make out what seemed to be some sort of detail on the top half of the planet, like cloud maybe? 

It was a nice sight with a clear separation of the rings and the planet, but no other detail of the casino devision could be seen. Though I also could see two moons of saturn i think? 

Again roll on better seeing, as 20 odd years ago i could make the cassini devision out on my Tal100r. 

But I'm putting that down to my sight being a lot sharper back then, and ideal seeing in the winter. 

I'm sure I'll be able to see it again in the 8" when conditions improve. Fingers crossed. 

 

[Spile]

On 18/08/2022 at 14:09, col said:

Iv only turned the locking screws lightly until they just touch so as not to move the circle over the dot. 

This is what iv managed up to now. 

I'll keep having a go though. 

Is this your latest image and/or have you got it sorted? If not, we really need to see the sight tube - can you place a sheet of coloured paper behind the focus tube and show the whole shot?

[col]

Hi Spile, sorry I missed this post as iv been struck down with a virus, not the covid one but a flu one and have been laid up. 

I'll get a picture on here as soon as Im able. 

[Moon-Monkey]

Great thread sorry your struggling a bit with collimation I’ve had my SL 8” about 14 months now and the things I see seen with this little beauty is outstanding !!!!! The 2” 2x Barlow is also excellent as it’s convertible with a separate removeabke cell giving about 1.5x I think which is nice to be able to do too I’ve been recommending this scope to people now for over a year !!!! Quality product from FLO and GSO 🙂🙂🙂