Unable to see clearly

[craig34220]

For starters I am a COMPLETE novice to a telescope , That being said , I purchased a Celestron 8 evolution  that came with a lens kit ( 4mm-20mm and a Barlow lens ) I also purchased a Celestron star diagonal, I still need to figure out how to get it aligned but I'll save that for another time, I have been moving it manually and have been able to find the moon in crescent and half stages. My problem is that I can see the moon very clearly by looking through the star diagonal without any lens, but when I put any  lens in the star diagonal I am unable to see anything clearly , moon, stars...etc. I originally thought that the OTA may need some alignment from shipping, but since I can see the moon nice and clear with just a star diagonal I figured that was not really my problem, any thoughts or hints on my problem? 

Any help would be great 

Thanks 

Craig

[Peter Drew]

Have you tried turning the knob on the rear of the telescope, this is the focuser.      🙂

[M40]

Helllo Craig and welcome to the site. Couple of questions for you, as Peter said, have you tried cranking the focus knob from end to end to see what happens? Start by using the weakest eyepiece you have which is the one with the highest number, your 20mm. Is your telescope new or a used device?

[craig34220]

Yes, I have tried turning the focus knob at the rear of the OTA, but no improvement 

[craig34220]

I've tried all the lens that came in the kit with the telescope ( package deal from High point Scientific ) 

[craig34220]

Telescope is a brand new unit

[Peter Drew]

It can take as much as 20 turns to get the telescope to focus.      🙂

[doublevodka]

Make sure you just have the diagonal and the 20mm eyepiece, with no Barlow to start with, then as above it may take many turns either way to bring it into focus, keep going till it stops (don't force it) and if unable to focus, go back the other way. Also bear in mind that when you are getting close to focus, you will need to go slower, you may laugh but some users will use a clothes peg attached to the focus knob for fine focus

[Elp]

As has been mentioned an SCT has a very long focus range and it can take up to a minute to rack focus from one end to the other. Be sure that when you're using a low power (high number) eyepiece that you are indeed pointed at an object, due to the long focal length of the scope you may find you're looking at blank space a lot if you don't know how to orient it. Using the moon as a target is good because even if the scope isn't centred on it you'll know you are near as you'll see the light from the moon through the eyepiece as a glare, the closer you get to focus the smaller the glare becomes and you might need to recentre the scope onto the moon. Luckily the moon is also a large object so quite difficult to miss.

Not so obvious to a beginner, you might also need to orient your body or eyes the right distance away from the eyepiece, some eyepieces black out if your eye distance isn't at the plane of focus. Depending on the eyepiece you either have to have eyeball stuck right into the eyecup or a bit of distance away from it, most eyepieces unless if they have long eye relief design will be the former.

Edited February 16 by Elp

[M40]

It's a strange thing to say, but the closer you get to focus the object gets smaller in the eyepiece. So pointing at the moon or a bright star, go end to end and as you approach focus you will see the object get smaller, if you pass focus the object will start to get larger. This gives you an idea of how close you are. As Elp and Peter has said, the focuser is a multi turn thing. I have a similar telescope from a different brand and I have about 30 turns end to end. 

Something that has just jumped into the brain is that in your telescope, the moon is going to be very very bright, do you have a moon filter? If not try and find a bright star to focus with. 

Edited February 16 by M40

[Cosmic Geoff]

2 hours ago, craig34220 said:

that came with a lens kit ( 4mm-20mm and a Barlow lens ) I also purchased a Celestron star diagonal

A new Evolution would come with one low power eyepiece, probably 25mm, and a Celestron diagonal, so what's been going on here?? A 4mm eyepiece would give far too much magnification with this scope, which has a focal length of about 2000mm.  Likewise there is no need to use a Barlow lens with these scopes.

If this scope is used and has lost its original diagonal and eyepiece, there is no telling what state it is in.  It could be severely out of focus AND out of collimation, meaning that even if it is in focus nothing will be seen clearly.

If possible, it would be wise to hand this over to someone (either a professional telescope repairer or an experienced amateur from your nearest astro society), who knows what he is doing. 

If it is in fact new and it doesn't work (rather than just being out of focus) you should return it to the seller.

To attempt focus, as others have suggested, fit the 20mm eyepiece, aim it at a bright star or Jupiter and wind the focus knob slowly. You  should see a glowing donut at some point. If so, wind the focus knob in the direction that makes the donut smaller.  You should eventually  get a bright point (star) or small disc (planet).  If the best you can do is something that looks like a badminton shuttle, the collimation is bad, and this is something a newbie is unlikely to be able to fix.

 

[craig34220]

Sorry I should have also mentioned that I have a Celestron  F 6.3 focal reducer screwed into the back of the OTA , and no moon filter, But will be purchasing one very soon. 

I have tried looking at a star as opposed to the moon, and I still have no clear view. I have tried with and without the Barlow lens and have turned the focuser knob all the way stop to stop,

 

[M40]

9 hours ago, craig34220 said:

I have a Celestron  F 6.3 focal reducer screwed into the back of the OTA , and no moon filter

Try it without the focal reducer or the barlow, just use the 20mm and the diagonal, make the optical chain as simple as possible at this stage. If you cant get focus using just these, there is something else going on. 

You don't need an expensive moon filter, you can always upgrade later if you want.

[Elp]

The F6.3 reducer is for imaging only as far as I know, with the standard accessories I don't even know how you've managed to put it together.

[Cosmic Geoff]

We still have no explanation as to why Craig34220  recieved the above mentioned accessories with the scope and had to buy a star diagonal.

Here is part of the spec from the Celestron site, and shows that a 40mm eyepiece, 13mm eyepiece and Celestron diagonal should have come with the scope: 

Focal Length:	2032mm (80")
Focal Ratio:	f/10
Focal Length of Eyepiece 1:	40mm (1.57")
Magnification of Eyepiece 1:	51x
Focal Length of Eyepiece 2:	13mm (.51")
Magnification of Eyepiece 2:	156x
Finderscope:	Red Dot Finderscope
Star Diagonal:	1.25" Star Diagonal

 So what happened to them and why were a 20mm eyepiece etc and Barlow supplied instead? If we get a sensible answer to this and confirmation that the scope is brand new and not a customer return, pre-owned etc we will be better placed to advise on how to sort the problem.

I also confirm that a f6.3 reducer is an imaging accessory. It is possible to use it with eyepieces but for troubleshooting it is best removed. I also point out that a Moon filter is NOT necessary - I have never used one.

The moon is a poor target for focusing, as unless it is almost in focus, all one can see is a bright blur with no clue as to which direction to turn the knob to improve focus.  Try again using a bright point source (star or planet) as I suggested above.

[Priesters]

My two penneth for what it’s worth is to try and get focus on a distant object in the daytime. It’s so much easier and gets you to rough focus for the night.

[Xilman]

Bahtinov masks work extremely well, IME. even when the scope is very far out of focus. A single adjustment, whether toward or away from focus doesn't matter, and it is clear which way to make other adjustments.

I find mine invaluable.

 

[craig34220]

14 hours ago, Cosmic Geoff said:

We still have no explanation as to why Craig34220  recieved the above mentioned accessories with the scope and had to buy a star diagonal.

Here is part of the spec from the Celestron site, and shows that a 40mm eyepiece, 13mm eyepiece and Celestron diagonal should have come with the scope: 

Focal Length:	2032mm (80")
Focal Ratio:	f/10
Focal Length of Eyepiece 1:	40mm (1.57")
Magnification of Eyepiece 1:	51x
Focal Length of Eyepiece 2:	13mm (.51")
Magnification of Eyepiece 2:	156x
Finderscope:	Red Dot Finderscope
Star Diagonal:	1.25" Star Diagonal

 So what happened to them and why were a 20mm eyepiece etc and Barlow supplied instead? If we get a sensible answer to this and confirmation that the scope is brand new and not a customer return, pre-owned etc we will be better placed to advise on how to sort the problem.

I also confirm that a f6.3 reducer is an imaging accessory. It is possible to use it with eyepieces but for troubleshooting it is best removed. I also point out that a Moon filter is NOT necessary - I have never used one.

The moon is a poor target for focusing, as unless it is almost in focus, all one can see is a bright blur with no clue as to which direction to turn the knob to improve focus.  Try again using a bright point source (star or planet) as I suggested above.

 

[craig34220]

Sorry for the delay, for reference I didn't know that the scope came with a star diagonal, but the the one I purchased seems better (  twist lock ) and the reason for the focal reducer is that in the future I hope to do some astrophotography . yes I miss spoke , I   purchased a lens/ filter kit with my telescope that has lens from 4mm to 40 mm and 2x Barlow.

The times I have used the moon  for focusing it has been in crescent and half stages and looking through the scope with star diagonal and  the focal reducer it has been crystal clear, when  I put any lens on the image get larger but unable to get focus. A big bright blur , like you said, and turning the focus knob didn't improve anything 

[Elp]

Ignore the Barlow for now.

The setup should be scope > back of scope visual back > diagonal > 40mm eyepiece. If you can see clear focus with just the star diagonal, you should be able to get clear focus with the eyepiece in it too unless something is drastically wrong with the eyepiece(s).

To save time, try it during the day pointed at a far off tree/building roof/pylon.

 

[Cosmic Geoff]

I hope the OP was not upset by my questioning his telescope's provenance. (I see that High Point Scientific are offering this telescope bundled with a generic eyepiece & filter kit). 🙂 We usually advise newbies not to buy these eyepiece & filter kits as many of the contents will get very little use, and the money would be better spent on two or three mid-price eyepieces. These kits usually include a neutral density filter which can be used as  Moon filter, so if he wants a Moon filter the OP should not have to buy one separately.

Since this is a new telescope, I anticipate that the problem is purely down to user lack of experience.  With the  powered 'tracking' not activated, the sky objects will as likely as not drift out of field while the user is struggling with the focus, and he may be trying to focus on the 'near moon' glare rather than the Moon itself.  As I mentioned above, it is actually quite difficult to get a totally out of focus telescope to focus on the Moon, and a point source target would be much easier.  The range of focus knob rotation where any Moon detail can be seen is quite small.  

An experienced user would figure out how to set the telescope to track by using the red dot finder only, but I suggest the OP tries to focus on Polaris (which does not move much) or a high contrast daytime target some distance away.

In addition to the suggestions above,  tree branches silhouetted against the bright daytime sky make a good focusing target. 

Finally, just check that something changes when the focus knob is turned, lest all the end to end twiddling has deranged the mechanism.

10 hours ago, craig34220 said:

and looking through the scope with star diagonal and  the focal reducer it has been crystal clear,

That is normal.  You just need to take the f6.3 focal reducer off, and find the focus with an eyepiece inserted.  

[dweller25]

Hello Craig and welcome to SGL.

I would suggest you remove the focal reducer for now, then put the star diagonal into the back of the scope, then put the 40mm eyepiece into the star diagonal, that will give you a magnification of x50.

Next, during the day point the telescope at a distant noticeable object a good mile away or more and look through the eyepiece and SLOWLY go through the entire focus range, clockwise and counter clockwise, this should at some point come to a focus - make sure you are not pointing the scope at the sky though or it will not work.

This is just to get you used to finding a focus point, this will need changing under the night sky as objects are further away.

What is the make of the star diagonal you are using ?

Also, do you have a local Astro club who could give you advice ?

 

 

Edited February 18 by dweller25

[dweller25]

Also Craig when you are using an eyepiece it shows much less sky then when looking through just the star diagonal without the eyepiece, so you could just be off target.

Edited February 18 by dweller25

[craig34220]

First I would like to thank all the good folks who were kind enough to share their knowledge and experience to a complete novice such as myself. 

I was able to finally get a clear view of the Moon and Jupiter , as it turns out I just need to keep turning the focus knob until the round dot in the lens ( secondary mirror ) was so small that it disappeared and my object became clear and WOW . It was nice to see Jupiter and it's moons.

I am sure I will need more help in the future but for now I'm enjoying what I can find from my suburban backyard.

Clear skies 

Craig