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Skywatcher Skyliner 200p focusing


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Good evening 

I wonder if I could pick the knowledgeable brains on here.

I recently bought a Skywatcher 200p; always having enjoyed star gazing whilst taking my dog out at night.

I set the scope up but couldn’t see much so decided alignment was the issue and bought an Amazon laser collimator. Unfortunately the collimator was not collimated itself so was returned in favour of a Farpoint unit with an additional Cheshire.

I spent this evening adjusting but find that when the laser dot is central on the primary mirror I cannot see one of the clips on the primary mirror. Vice versa, if I adjust so that I can see all 3 primary mirror clips, the laser dot is an inch off the primary centre dot.

I can see stars though the scope but they don’t appear very magnified. In fact the view through finder scope is better.

I have read through this forum for clues. I am not using both the 1.25 and 2.0 adapters at the same time as suggested with other members problems.

Any assistance wound be great appreciated. As mentioned, I am a complete novice and am struggling here.

 

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Stars will just be pinpoints of light and will never be “magnified” in yoir scope. They will look small when properly focused. What you should be seeing is a lot more stars through your scope than the finder. 

Things such as the moon and planets however will look bigger as you  increase magnification but there is such a thing as too much magnification. The stock 10mm eyepiece isn’t very good but the 25mm is at least usable and not that bad. First upgrade most do is getting better eyepieces.

Edited by johninderby
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Hi @WilsonTD and welcome to SGL.

 

Stars are tiny points of light. When you magnify them, they are still just tiny points of light - you just see more of them! However, as you approach the scope's magnification limit, they will become bloated and fuzzy, especially if the seeing is poor that night. Poor collimation will make things worse too.

Speaking of collimation, I think your secondary mirror is twisted. That will explain why things are out-of-whack when you centre the laser dot on the primary. Have a look at this:

 

Your secondary looks rotated to me, as well as being off-centre:

image.png.0ebdf6f401ed9172859314f445c60fbd.png

 

It's always hard to tell from a photo, since we don't know how well your camera is centred with respect to the focuser. However, this is how you use the Cheshire as a 'sight-tube' to position the secondary. In the above picture, the red circle and cross-hairs are the view through the Cheshire. Firstly, you need to adjust the secondary's position so that the outside of it (yellow) it is centred within the red circle and also a perfect circle, concentric within the red circle. It's easier if you can get the Cheshire in closer, so that the secondary nearly fills the view.

Once that's done, and you only need to do it once, you can adjust the secondary tilt so that it's aligned with the primary doughnut marker. 

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12 minutes ago, johninderby said:

Stars will just be pinpoints of light and will never be “magnified” in yoir scope. They will look small when properly focused. What you should be seeing is a lot more stars through your scope than the finder. 

Things such as the moon and planets however will look bigger as you  increase magnification but there is such a thing as too much magnification. The stock 10mm eyepiece isn’t very good but the 25mm is at least usable and not that bad. First upgrade most do is getting better eyepieces.

Thank you for that. What eye pieces would you recommend please. 

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The BST Starguiders are well regarded as very good budget eyepieces. Best to start with just 9ne and slowly add a few more as you go on. Never make the mistake of buying a load of eyepieces all at once but see how you get on with the first one. 

https://www.firstlightoptics.com/search/for/starguider

Collimating is something ypu will need to do with ypur 200p. Can be a bit daunting at first but once you get the hang of it no big deal. Lots of youtube vids on the subject.

Edited by johninderby
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10 minutes ago, Pixies said:

Hi @WilsonTD and welcome to SGL.

 

Stars are tiny points of light. When you magnify them, they are still just tiny points of light - you just see more of them! However, as you approach the scope's magnification limit, they will become bloated and fuzzy, especially if the seeing is poor that night. Poor collimation will make things worse too.

Speaking of collimation, I think your secondary mirror is twisted. That will explain why things are out-of-whack when you centre the laser dot on the primary. Have a look at this:

 

Your secondary looks rotated to me, as well as being off-centre:

image.png.0ebdf6f401ed9172859314f445c60fbd.png

 

It's always hard to tell from a photo, since we don't know how well your camera is centred with respect to the focuser. However, this is how you use the Cheshire as a 'sight-tube' to position the secondary. In the above picture, the red circle and cross-hairs are the view through the Cheshire. Firstly, you need to adjust the secondary's position so that the outside of it (yellow) it is centred within the red circle and also a perfect circle, concentric within the red circle. It's easier if you can get the Cheshire in closer, so that the secondary nearly fills the view.

Once that's done, and you only need to do it once, you can adjust the secondary tilt so that it's aligned with the primary doughnut marker. 

… and thanks for the video too. I’ll take a look 👀 

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The Skywatcher supplied 10mm eyepieces are variable. Some are OK. Others better suited to conversion to salt pots.

The scope itself should be very good. These are often buoght as a first scope, but kept for years.
I bought an 8" Newt (Orion Optics) in 2003. Despite all the scope comings and goings, I have always had at least one reflector in this sort of size range.

Don't forget, even the best scopes won't give good views at high magnification if the 'seeing' isn't good.
This is a combination turbulence, pollutants, water droplets, etc.

See what happens using the 25mm eyepiece. Yes magnification is lower. But collimation is less of an issue.
You will get a good feel for well the scope performs. Stay with easy tagets for now.
Have a wander around Orion in the belt region. You should be astounded by how many stars are visible.
Similary clusters like Pleiades (M33). The seven sisters becoming dozens.
On both, the nebulae should start to show the wisply gas around the stars, thanks to the huge light gather you have.
Close ups of lunar craters should also be astounding.

There is a learning curve with observing. Things don't immediately leap out.

When you do start collimation, just take it slowly. Make sure the scope is obviously mechanically square before trying to tweak optics.
I have had scopes that required attention in this area before aligning mirrors.
The good news is that these reflectors are very easy to sort out for alignment/collimation using only basic tools.
If in doubt a visit to a local club will probably result in very helpful assistance.

Keep asking the questions. Enjoy the journey.

David.

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28 minutes ago, Carbon Brush said:

The Skywatcher supplied 10mm eyepieces are variable. Some are OK. Others better suited to conversion to salt pots.

The scope itself should be very good. These are often buoght as a first scope, but kept for years.
I bought an 8" Newt (Orion Optics) in 2003. Despite all the scope comings and goings, I have always had at least one reflector in this sort of size range.

Don't forget, even the best scopes won't give good views at high magnification if the 'seeing' isn't good.
This is a combination turbulence, pollutants, water droplets, etc.

See what happens using the 25mm eyepiece. Yes magnification is lower. But collimation is less of an issue.
You will get a good feel for well the scope performs. Stay with easy tagets for now.
Have a wander around Orion in the belt region. You should be astounded by how many stars are visible.
Similary clusters like Pleiades (M33). The seven sisters becoming dozens.
On both, the nebulae should start to show the wisply gas around the stars, thanks to the huge light gather you have.
Close ups of lunar craters should also be astounding.

There is a learning curve with observing. Things don't immediately leap out.

When you do start collimation, just take it slowly. Make sure the scope is obviously mechanically square before trying to tweak optics.
I have had scopes that required attention in this area before aligning mirrors.
The good news is that these reflectors are very easy to sort out for alignment/collimation using only basic tools.
If in doubt a visit to a local club will probably result in very helpful assistance.

Keep asking the questions. Enjoy the journey.

David.

Thanks David for all of that brilliant advice. 

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I would get your secondary aligned first. If you follow the steps (in order) I have listed here you will see an improvement.
https://astro.catshill.com/collimation-guide/

It’s important to get the cross hairs of your sight tube aligned with the centre mark of the primary and the secondary circular.

Edited by Spile
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