Yet to leave the planet - I can't focus on the horizon

[John Barrow]

I have just finished setting up my new telescope (Skywatcher EQ120) and have managed to mount it and balance it for both R.A and Dec. and so the next task is to align the finderscope. Now I have a small problem here in that this telescope does not come with one (optional extra) and so that is ordered (although out of stock at the moment).

In the mean time, part of aligning the finderscope is to point the telescope at a distant point on the horizon and focus in on that. As I can't really do anything until the finderscope has arrived I thought that I could still do this just to see the magnification and image quality of the telescope. The National Grid have conveniently positioned a line of telegraph pylons a couple of miles away and I can clearly see them with the naked eye and through binoculars (I wear glasses but take them off when using the binoculars).

Now my problem. Having inserted the 20mm eyepiece (the weakest one I have) and removed the lens cover, I can only see a pure whiteish image through the eyepiece. If I move the scope up and down slightly, it changes brightness which looks to relate to the difference in the sky and ground (above / below the horizon). However, I have used the focus knob to move the tube to its fullest extent and back again (it has a range of about 12.5cm) and the image never changes. There also appears to be a focus ring on the eyepiece but rotating that doesn't seem to have any effect either.

Therefore as I can't even get an image on something I recognise, I don't hold out much hope being able to focus on the planets / stars once the weather improves.

My questions

a) Any tips on getting the telescope to focus on a terrestrial object - i.e. Should I expect the image be a complete blur most of the time apart from a very narrow point and I just need a lot of patience to move the focus very slowly to try and find it?

Does rotating the eyepeice affect the ability to focus and if so, do I need to try a combination of the eyepiece and telescope focus (which is a lot of combinations!)

c) Should I just skip the terrestrial focussing and try and focus on the moon when it is next visible?

d) If someone has a similar scope, how far out is the tube when focussing on a terrestrial object (i.e. value between 0 - 12.5cm)

e) Am I missing something obvious (apart from removing the lens cover)?

f) Do I have to wait until the finderscope arrives before attempting this in order to check that I am aligning the telescope accurately (although a 'Yes' to this point would appear to create a "chicken & egg" situation in that there is an assumption you can focus both independently in order to accurately align them)

Thanks in anticipation of being able to solve this and so move on to the next stage once I can get an albeit inverted image from the lelescope of one of these pylons.

[brantuk]

Are you using a diagonal? Are you sure your object is a good mile or two away? Also - it may sound daft but are you trying to focus outside or from within the house through a window. What specifc ep are you using? That focus ring sounds strange - are you positive it isn't a twist up eye relief? In any event the ep should stay in a constant position to focus the scope.

The focus point will be at a very specific point so you need to go real slow or you might be going past it without realising. Are you positive all packing materials are removed and dust caps off all ep's. I know they sound like dumb questions but there's something very simple here that's not obvious. You won't need the finder to focus the scope.

[Chris H]

I'm with you on that brantuk, double check everything and you should be able too focus on and see something even without that finder scope.

[Dave-Ryan]

To me it sounds like you are just putting the eyepiece directly into the focuser. You will need to use either a diagonal or an extension tube to get your eyepiece to come to focus.

Did you get a diagonal with your telescope?

[Helen]

The only other thing I can think of is that you are pointing too high and just seeing sky.....

Helen

[John Barrow]

Morning everyone,

Firstly thanks for the quick responses.

> Are you using a diagonal?

No - one didn't come with the telescope. The purist in me believed that a diagonal was an optional extra that was used for comfort rather than necessity. As every extra peice of glass between you and the lens 'loses' something I thought that I would see what the 'best' image you could see just using the eyepiece and then purchase a diagonal to compare. However, if that is not the case (i.e. just a matter of personal preference) then that would explain why I can't get a focus point.

> Are you sure your object is a good mile or two away?

Yes, in fact they are proabably further as they are only a couple of cms high with the naked eye.

> Also - it may sound daft but are you trying to focus outside or from within the house through a window

Not daft at all, as yes I am currently setup inside the house (as it is raining / misty here at the moment) and so didn't want to get the lens wet. While I appreciate that the glass will seriously distort planetary / star images, I thought that a simple terrestrial view it would be ok (as it is fine with binoculars) and only magnifying x45 (f 7.5 - 900mm * 120mm aperture) using a 20mm eyepiece. Also, I can clearly see the pylons from upstairs (better view)! Do I just need to wait until we get a sunny day and try again outside?

> That focus ring sounds strange - are you positive it isn't a twist up eye relief?

That will be it - they are the long-relief eyepieces and I didn't think of that as an explaination (thanks!), but equally well couldn't understand why an eyepiece wasn't fixed

> The focus point will be at a very specific point so you need to go real slow or you might be going past it without realising

That was my initial thought - I have been going fairly slowly but I was expecting at least a change in the resolution of the image but as it was just a constant light regardless of how I adjusted the focus I don't have anything to 'home in on'. I am assuming that the effect should be similar to that experieinced through binoculars. Thats why I jumped on to the forums to check that I wasn't wasting my time.

> Are you positive all packing materials are removed and dust caps off all ep's

I will check again at lunchtime (at work at the moment) but I have removed the following

a) The lens cover from the front of the telescope

The blank 'plug' from the telescope where the eyepeice sits

c) Plastic bag packaging from around the eyepeice, however, I don't recall it having a dust cap as well (the eyepeices are in their own box)

When I replace the lens cap, the light from the eyepeice disappears (i.e. now black) and so I believe that light is at least getting all the way through although if there is, say, a white packing disc in the way then that might be the case, but I don't think so.

> To me it sounds like you are just putting the eyepiece directly into the focuser.

I am!

> You will need to use either a diagonal or an extension tube to get your eyepiece to come to focus. Did you get a diagonal with your telescope?

As mentioned above, neither of those. There is a 2" to 1.25" adaptor already in the telescope but I have not tried taking that out to see if that acts as an extension tube.

Therefore, looks like I need to extend my shopping list to include these two items before trying again as that would most likely explain the effect that I am getting.

Thanks again for all the information and sounds that (subject to the post being reliable and the weather improving) I can move my telescope out into the garden just after the New Years celebrations .

[Dave-Ryan]

You don't need both the extension tube and a diagonal.

The diagonal is for visual use as it makes viewing more comfortable.

The extension tube is for imaging as this give the camera something solid to connect to the telescope with and help to prevent flexure which a camera connected to a diagonal can cause.

[Dave-Ryan]

Try holding an eyepiece behind the focuser and moving it to see if you can bring it into focus. This should give you and idea of how much distance you need between the focuser and the eyepiece.

[brantuk]

Hi John - that's great extra info. Ok - first thing - you'll deffo need a diagonal which should be enough to obtain focus. The Revelation one is a v.good basic diagonal - get the 2" one if you can afford it and remove the adaptor when fitting to the scope.

An extension tube is an optional extra usually for when you have a camera attached. It replaces the diag and sets the chip at a specific distance from the scope in prime focus photography.

Through an upstairs window during daylight is good for finder alignment and focus testing and the pylons are great to use. Focus on the top tip for best results. However - for the stars at night you need to wrap up warm and get out in the elements lol. Give the scope a good 45mins to an hour to cool down to ambient temperature for best viewing.

The eye relief won't affect the focusing so long as the ep lens is fixed in place. It's more for "eye comfort" and people who wear glasses.

So long as you can see light through each part of the equipment then you'll have a clear light train when assembled. Ep's usually come with caps top and bottom and so too will the diag.

Rotating the focuser tube is standard in this type of scope - set in place for best viewing comfort and lock before focusing.

I think that covers everything - do shop around for best prices on the diag. FLO will pricematch if poss - give them a call before ordering and they'll get you best vfm (they often have great offers on).

Feel free to ask if you have any other questions (bound to happen when the extra bits arrive lol). That's a very nice scope you have there by the way - you'll enjoy it for a good while to come

[chrisp]

Try removing the eyepiece and looking down the tube with your eye.

You should be able the objective lens showing a blurry image of whatever it's pointing at.

As you move the scope you should see the blurry image change as it points at different things. Once it's pointing at something, put the eyepiece back and try focussing.

[Ant]

Is this the scope that you have?

http://firstlightoptics.com/proddetail.php?prod=ev120eq32

If it is then it should have come with a diagonal. The diagonal is vital to reach focus in a refractor. Speak with your supplier and get them to send you one - it's crazy that it isn't supplied as standard as the scope cannot be used visually without it (or an extension tube).

What you can do is wind the focuser all the way out - then carefully undo the screw holding the EP in place and start to slide the EP out of the focuser - you might just get enough additional out focus to reach the focus point...

But you do need the diagonal.

If your telescope came with a cheapy 2xbarlow, you could (again carefully) unscrew the lens part - this is usually detachable - and what you are left with is effectively an extension tube use that between the focuser and EP.

HTH and welcome to SGL.

Cheers

ant

[John Barrow]

I have ordered a diagonal (William Optics 2" Dielectric Diagonal) from FLO (and beat the VAT increase) although I still need to wait until the end of January for the Finderscope as that is out of stock. I may have a hunt around tonight and look for an alternative (was looking at the Skywatcher 9x50 Right-Angled Erecting Finderscope).

> Through an upstairs window during daylight is good for finder alignment and focus testing and the pylons are great to use. Focus on the top tip for best results. However - for the stars at night you need to wrap up warm and get out in the elements lol. Give the scope a good 45mins to an hour to cool down to ambient temperature for best viewing.

I am looking forward to getting out there and we are lucky in that the garden points SE over open fields and so Orion and all the planets are lined up waiting to be 'shot at'. However, we will need to travel to get good views of the northern half as looking over the whole town and lots of light pollution, hence the selection of the EQ120 as it got good reviews, refractors are good for the planets and still portable for trips out.

By the way, finding hills in Lincolnshire can be a bit of a challenge but the early morning / late evening dog walking has enabled me to find a couple of small 'bumps' and the location of some darker skies to target initially.

Having said all that as most of my time at the moment is spent stuck in a book / manual / laptop learning all the various controls, the upstairs bedroom is just so much more convenient and the laptop isn't waterproof (to my knowledge)!

> Rotating the focuser tube is standard in this type of scope - set in place for best viewing comfort and lock before focusing.

Sorry, but I don't understand what the 'focuser tube' is. If this refers to the main telescope tube, then I have rotated that as part of the balancing so that when the finderscope arrives it sits on top and is out of the way of the tube locking nuts. However, I suspect that isn't what you are referring to and instead are talking about the tube that extends as you rotate the focus knobs, so I am not sure why you would 'rotate it' and how you then 'lock it'?

> Try removing the eyepiece and looking down the tube with your eye.

> You should be able the objective lens showing a blurry image of whatever it's pointing at.

I will give that a go at lunch if the fog hasn't settled back in by then - it did briefly look like it was lifting earlier.

[brantuk]

John - please scratch my comment about rotating the focusser tube as I misread one of your questions - so not applicable. You can of course rotate the whole tube for positioning comfort but shouldn't be necessary once you have the diagonal which can be rotated instead.

The WO 2" dielectric is great (I have the same in CF) very nice diagonal good choice. A right angle finder is a good idea if you suffer a bad back or neck strain - I use the Orion ones but there's nothing wrong with the SW's. The 9x50 covers a wider angle of sky which I prefer to 9x30.

Take a wonder over to East Mids Stargazers social group and join up (yes we cover Lincolnshire too). Some of the guys live out your way and are in the process of organising a dark site to meet up for group observing. They might be near you. (click the link in my signature). We also have two dark sites around Notts/Derby if you're ever out this way.

[xyz]

John, a question. Did you buy this scope new from a supplier or second hand. Because if new, as standard it should have come with the necessary diagonal to make it usable. If second hand, then the seller was at best, not very kind to you.

[John Barrow]

Is this the scope that you have?

Evostar - Skywatcher Evostar 120 (EQ3-2)

Not quite

Skywatcher Equinox 120 APO PRO OTA

at the bottom of this page

Equinox

[John Barrow]

John, a question. Did you buy this scope new from a supplier or second hand. Because if new, as standard it should have come with the necessary diagonal to make it usable. If second hand, then the seller was at best, not very kind to you.

Yes, it was new from OpticStar

Sky-Watcher Equinox 120 PRO Fluotite ED telescope.

The service, I thought, was first class but I may have misled him in wanting to view the image straight on to start with, rather than via a diagonal and understand the difference as I expect most of my viewing will be focused on the planets and moon initially. However, it would have been nice if they had mentioned that an extension tube was needed if a diagonal wasn't used.

My main issue is with the quality of the Skywatcher documentation. It could have been a lot more informative. For example, there was no mention of where two packaged bolts go (eventually deduced that they were called the T-bolts and used for adjusting the altitude) and as they are different lengths, which side each goes. I eventually worked that out for myself when I needed to raise the telescopes altitude for balancing. Even now, there are two spanners included with the mount that I have no idea why they should be needed and no reference within the manual and so on.

[Earl]

My main issue is with the quality of the Skywatcher documentation.

That is quiet often the case and not just with Sky-Watcher.

[Ian123]

That is a very nice scope which i think does not come with Ep's or a diagonal

If you are still having problem's i will swap my explorer 150p (with EP) go on!!

[Ant]

That does explain why there is no diagonal the Equinox scopes are more aimed at imagers I suppose - imagers wouldn't really use a diagonal .

Where abouts are you in Lincolnshire...? Anywhere near the Peterborough area (which I do realise isn't in Lincolnshire but it is close...) ?

Cheers

Ant

[brantuk]

Scratch my comment about scratching my previous comment lol - the focuser tube actually is rotatable by 360 degrees as I first suspected. There will be a locking screw under the focuser tube near the scope body (or possibly a small allen key bolt).