I See Rings Through My Telescope

[MVP2004]

Hi guys I am new to astronomy, tonight was my 3 night with my new Nexstar 6SE and sense my first night with it I have been seeing these rings with a black dot in the middle I was hoping I can get any advice on how to get this to go away I had A 2x barrow and A 25mm. If anyone can help please let me know thank you.

[Cornelius Varley]

Hello and welcome to SGL. I believe your problem is that you have not focused the telescope properly.

[MVP2004]

I have Tried spining the focus knob both ways all it does is zoom in and out

 

 

[faulksy]

as said by peter, you are to far out of focus. try your longest focal length eye piece(this is the eye piece E.P. with highest number, lowest magnification) without the barlow and find a bright star and turn the focuser untill its sharp in the ep. it is then focused and the ring will disappear

[alanjgreen]

As said above, you are "out of focus"

SCT scopes have a huge focus range, something like 40 turns of the focus knob from one end to the other.

setup in the daytime and point the scope at something 200yds or more away.

look through the eyepiece and turn the focus knob slowly clockwise, repeat until you are in focus and the view is sharp or until you have done 20 turns.

if still out of focus do 40 turns anti-clockwise or until image is sharp.

THEN

at night when you next look at a star, you will only be slightly out of focus, turn the focus knob slowly, if the stars get smaller then you are turning the right way, keep going...

if the stars are getting bigger then you are turning the wrong way, turn the other way instead...

 

Alan

Edited December 29, 2016 by alanjgreen

[MVP2004]

i have tried my 8mm without and with the baralow and the same thing with my25mm

 

[alanjgreen]

Once you see stars as a small point of light then you are focused.

stars only ever appear as a small dot.

 

[John]

Does what you see change at all when you turn the focus knob ?

If it remains looking exactly the same, and the same size then the focus knob is not adjusting the focus as it should.

 

[alanjgreen]

2 minutes ago, MVP2004 said:

i have tried my 8mm without and with the baralow and the same thing with my25mm

 

Start with the 25 mm and no Barlow.

 

[alanjgreen]

The focus knob is working, MVP can see the stars getting bigger/smaller, he refers to it as zoom in, zoom out in his text.

mvp - the focus knob is not a zoom button!

if the shape is getting bigger then you are turning the wrong way

turn the knob to make the shape smaller and smaller until it is a dot 

now stop, you are focused.

you now need to move the scope up and down to find something to look at, the nexstar should do this for you once you complete the alignment procedure following the instruction manual

 

[alanjgreen]

It will all be much simpler if you wait for the moon to come or have a play in the daytime

DO NOT POINT IT AT THE SUN!

if you try in the daytime then the image will be back to front - this is how SCT work and there is nothing wrong with your scope

but at least you can practice focusing to a sharp clear image.

Edited December 29, 2016 by alanjgreen

[MVP2004]

i tried that with venus and it looks like a star you would see with your eyes

 

[alanjgreen]

That is what Venus looks like! Venus is a dull object to view.

you are doing it right!!

align you scope and choose Messier 42 from the deep sky list on the handset , if you want to see what it can really show

Edited December 29, 2016 by alanjgreen

[MVP2004]

also how small movements do you have to make with the focus knob

[alanjgreen]

Once you find the focus point with one eyepiece, then maybe one turn if you swap to another.

if you put the Barlow in then maybe more turning will be needed.

just keep your eye on the stars and keep bringing them to small dots of light.

Edited December 29, 2016 by alanjgreen

[MVP2004]

 

thank you so much you have been a lot of help I will tell you if it works tonight also if you have a heater can i know witch one because i get really cold when i'm out there

 

[alanjgreen]

MVP,

your 25mm eyepiece is your low power. Your scope has a 2000mm focal length, dividing one number into the other tells us that it will give you x80 magnification.

the Barlow will halve the 25 to 12.5, so if you use the 25 and the Barlow you will get x160 magnification.

stick with these for now and ignore the 8 mm, it will give you x250 and this is too much for general use. Try this on the moon when it appears next week.

you may want to add an eyepieces around 16/17mm at some point, giving x120

you have a great scope there, take a few weeks to get used to it.

you would be surprised how many people have a bad first night out. It gets better from here on....

[alanjgreen]

I wear two layers of everything this time of year. Wear boots with a thick sole to keep the cold out. Hat and fingerless gloves also recommended.

after an hour go back inside for a hot drink then go back out again.

 

[SonnyE]

When I had that problem I just needed to move my telescope....

I was staring at Saturn.

[A budding astronomer]

Your telescope is out of focus buddy, as mentioned above SCT telescopes are very finicky when focusing. Try putting in a low powered eyepiece and try observing a bright star like Betelgeuse, Sirius or Aldebaran or a bright planet like Jupiter, Venus or Mars and focusing until you get a small star or a clear disc on the planet.

In my opinion for someone starting out a 6" SCT is very large. By getting a smaller telescope like a 4" even "5 reflector it will save you alot of money and will be easier to setup, transport, maintain and in some cases use.

Clear Skies!

Adam

 

 

[alanjgreen]

1 hour ago, A budding astronomer said:

In my opinion for someone starting out a 6" SCT is very large. By getting a smaller telescope like a 4" even "5 reflector it will save you alot of money and will be easier to setup, transport, maintain and in some cases use.

Clear Skies!

Adam

 

 

Sorry but I have to disagree with this opinion.

It is always best to buy as big as you can afford, buying small means you SEE LESS and outgrow the scope much quicker or give up all together. How does having to buy a second scope (bigger) save you money?

I also don't think it helps the OP with his focus question!

 

Edited December 31, 2016 by alanjgreen

[A budding astronomer]

5 minutes ago, alanjgreen said:

Sorry but I have to disagree with this opinion.

It is always best to buy as big as you can afford, buying small means you SEE LESS and outgrow the scope much quicker or give up all together. How does having to buy a second scope (bigger) save you money?

I also don't think it helps the OP with his focus question!

 

I did try helping him in the first paragraph I wrote, I was just telling him in my eyes that a smaller telescope would be better for a beginner that's all.

Adam

[Stu]

4 minutes ago, alanjgreen said:

Sorry but I have to disagree with this opinion.

It is always best to buy as big as you can afford, buying small means you SEE LESS and outgrow the scope much quicker or give up all together. How does having to buy a second scope (bigger) save you money?

I also don't think it helps the OP with his focus question!

 

I do agree with this. Let's keep the thread on topic which is about helping mvp to focus his scope. A 6" SCT is a perfectly normal scope to start out with.

[SonnyE]

Unless you plan on doing Astrophotography...

Then a smaller APO scope can be great.

For observing, a nice 6" kit telescope is a great start.

[LukeSkywatcher]

I agree that the SCT is very finicky to focus. You could start at 8pm and still be turning the focuser at midnight...only to find you've been turning it in the wrong direction.

Maybe the scope is out of collimation?.

p.s.~Nothing wrong with a big scope as a starter scope.

Edited January 1, 2017 by LukeSkywatcher