Skywatcher 150p tabletop scope.... collimation help needed

[Alex_o0]

Hi friends,

My first telescope arrived today and all the tightening screws on the primary had fallen out. They were lose in the box.

When I look into the scope with it faced to a white wall , I see my eye in the middle but the rest of the image is the back of the scope (behind me). I'm assuming that my secondary is heavily not aligned ?

Am I supposed to see the white wall as the rest if the image ? (example if i wave my hand in front of the primary I see nothing , but behind the secondary I see my hand. (images attached)

 

Sorry for the noob question,I have telescope compilation cap and little confused about the secondary

 

Edited September 10, 2020 by Alex_o0

[Bruce Leeroy]

The reflections your seeing are what you'd expect to see and normal. I can't tell from the pics how good the collimation is but I would advise leave it as it is and try it out on the night sky before adjusting anything.

[Alex_o0]

Thanks @Bruce Leeroy trying it outside I’ll I see it white. What would that suggest ?

[Bruce Leeroy]

Point it at a roof or tree and draw the focus tube outwards...if the image is still not in focus then release the eyepiece and slowly draw it out and see if focus is achieved.

Use a 20mm eyepiece rather than the 10mm

Edited September 10, 2020 by Bruce Leeroy

[Starwatcher2001]

Point the tube at a building or some such 1/2 mile away if you can, put an eyepiece in and see if you can get focus.

 

[Captain Scarlet]

Put one of the eyepieces, the one with the largest number on it, probably 25, in the large hole in the middle of the large hexagonal shape in your first pic and secure it in place with the the two grub-screws. Not tightly though, just enough to hold the eyepiece in place. The number on the eyepiece corresponds to the focal length, in mm, of the eyepiece. The whole scope magnification is then the focal length of the main mirror, 750mm divided by the eyepiece focal length, in this case 25mm, giving you 30x magnification.

Point the open end of the main tube towards a distant object, say a tree. Look into the eyepiece and bring to focus by screwing the whole eyepiece assembly in or out.

 

Cheers, Magnus

[Bruce Leeroy]

I think the sun has well set in Melbourne, hopefully they are just enjoying the views

The 1st minute of this video applies to your type of scope.

 

Edited September 10, 2020 by Bruce Leeroy

[Alex_o0]

Thank you all so far I can see stars I think😁

I don’t know how good collimation is but can see a group of white dotes with 25 Eyepiece. Jupiter  and Saturn are right above me but this being my first telescope experience I will need to have a lot more of play to see them 😊

[Alex_o0]

I think I can see Jupiter so bright !!! What a sight. My need something to dim it in the future 

[Bruce Leeroy]

4 minutes ago, Alex_o0 said:

Jupiter  and Saturn are right above me

You should try Saturn, locate it using the 20mm eyepiece then if your confident you've found it swap to the 10mm eyepiece and refocus to see the ring in better detail...if that goes well you should align the red dot finder while Saturn is central in the view then swing to Jupiter using the red dot finder (you have to get your head at the correct angle to see the red dot reflected-make sure to turn it on).

 

[Bruce Leeroy]

2 minutes ago, Alex_o0 said:

need something to dim it in the future 

Try sunglasses for now or if your scope came with a moon filter use that!

[Alex_o0]

I saw Saturn wow I’m dancing around !!! 
My red dot finder is a little off but finally can make it out with the rings !!! 
thank you !!

[Bruce Leeroy]

Saturn and Jupiter are something special , so long as you know how far off your RDF (red dot finder) is then all you need to do is keep placing the red dot offset for now and tune the alignment during the day if that's easier.

Ment to add...make sure to download stellarium its a free night sky utility (for PC) that will help you find/identify objects.

Don't forget to turn off your RDF when your finished for the night, it's always a face palm moment for me the next day when I find its been left on all night and drained the battery, don't talk to your eyepieces either or they will fog up with condensation

Edited September 10, 2020 by Bruce Leeroy

[Alex_o0]

Appreciate all the guidance and help @Bruce Leeroy thank you 😊 

[Starwatcher2001]

... and that's how Alex became known as "The Dancing Astronomer"... 🤣

Glad you're up and running and hope that you have many more such moments as you explorer the universe. This can sometimes be a frustrating hobby, especially with the weather and getting kit sorted, but now and again there's a moment like this that blows your socks off.

[Alex_o0]

HHahaha thank you @Starwatcher2001 

well said and I have a lot to learn  I’m also gonna need a taller table , there was lot of bending involved 😁

 

[Starwatcher2001]

Consider sitting. It's a lot more relaxing and a better way to observe.

[KevinPSJ]

Hi. I was out looking at Jupiter and Saturn last night too but in my case they were skimming the rooftops rather than high overhead and my worry wasn't collimation but turbulence above my neighbours house. Oh well.

If you are still interested in learning more about collimating your scope, have a read of https://garyseronik.com/a-beginners-guide-to-collimation/  - it's really clear, detailed and helpful. I'd guess you only need to worry about collimating your primary unless you are really unlucky so initially I'd concentrate on using the collimation cap to get your primary aligned.

Have a read of https://garyseronik.com/no-tools-telescope-collimation/ once you think you have understood the first link - it shows a fairly simple way to check your collimation using real stars and fine tune things once the stars come out.

I'd advise also looking at Mars by the way - it's a real treat at the moment as it's getting closer to earth by the week with maximum brightness peaking in Oct. Don't miss out!

[Alex_o0]

Does anyone happen to know what the eye relief is for the Eyepieces that came with the scope ? I cant seem to find them anywhere.

The reason I'm asking it because I wear glasses  and want to get a feel for what I have and what the upgrades are (are they below 20mm eye relief example for example)

Eyepiece 1.25″ Super 25mm (26x)
Eyepiece 1.25″ Super 10mm (65x) 

Edited September 11, 2020 by Alex_o0

[Pixies]

It's roughly 2/3 of the fl.

 

So 25mm EP - 17mm eye relief

10mm EP -  7mm eye relief

[Starwatcher2001]

I can't answer your question directly Alex, but I can offer my own thoughts about glasses.

I am quite long sighted (glasses like jam jar bottoms) and have astigmatism. I thought I would be constrained to always wearing glasses and using long eye-relief eyepieces. But it turns out that my astigmatism is only a problem with higher focal length eyepieces, where stars look like lines unless I wear glasses. At lower focal lengths (higher magnifications), my astigmatism doesn't affect me, and I can simply change the focus to deal with the long-sighted problem.

So for me it's glasses for 25mm (94x) and lower powers, and no glasses at higher powers.  I went out and bought a Celestron x-cel LX 9mm with 16mm eye-relief, but find I actually prefer it without.

As you move to higher powers, glasses can give another problem and that's smaller exit pupils. The exit pupil is the width of the beam of light coming through the eyepiece. A small exit pupil is like looking down a straw, especially in glasses. Exit pupil is directly related to the magnification you'll get from the eyepiece in your scope, so (as I understand it), shopping around amongst different manufacturers doesn't help. In your scope, a 25mm (26x) eyepiece from one manufacturer would have the same exit pupil as one from any other.

Eye relief on the other hand is related to the design of the eyepiece, so eyepieces with the same focal length from different manufactures does make a difference.

You may be equiped with a different model of eyeball of course, but it's worth checking if you do actually need long eye-relief eyepieces.  The only downside is putting the perishing glasses back on to read the charts and find my coffee mug!

Cheers!

Edited September 11, 2020 by Starwatcher2001
typo

[Alex_o0]

Thank you @Starwatcher2001 and @Pixies for your answers and help!