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Help with 10mm EP


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Help, this is all new to me and I have to ask a stupid question or I’m being totally stupid. I recently purchased a secondhand sky watcher 200.  It came with both a svbony 34mm and a super 10mm eye piece.

I’ve just been looking at Jupiter thru the 34mm ,lovely, I can see the 4 moons and the shade of the belt. However when I put the 10mm in, I can’t see anything ,it’s just a blur. I tried different combinations with  the various eye piece parts supplied, (see pic) but no success. What’s the obvious thing I’m doing wrong ?

Yours very gratefully 

John

2B8FBC38-E255-4B3E-B7B1-CAA39168B071.jpeg

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Hi, several possibilities. First of all, your telescope has not cooled adequately allowing thermals to escape from the tube. secondly the seeing conditions, the atmosphere might be unstable, meaning that as you increase power the image becomes distorted. Are you achieving focus with this eyepiece? A focal length somewhere between the two would be very useful i.e. 14 - 15  or 16mm. Also check your collimation. 

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Many thanks to you all for your prompt replies.

the scope had been outside for an hour before I started gazing..

After several permutations ,I definitely used the 1.25 adapter only. In reply to scarpe15. I’ve not had one decent focus  thru the 10mm. how do I know the eye piece is not faulty?. It does not rattle when I shake it, there’s no sign of a crack.

im planning to clean the mirror and Set the collimation on Tuesday, as 2 nights of clear skies are forecast (fingers crossed)

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Once you have established that the collimation is good, if the eyepiece still gives a blurry image , it could maybe have a greasy fingerprint or similar on the exposed top of the lens ? If it is the stock skywatcher 'Super MA' which looks like this :

1013831-550x550.jpg

it may be that you are seeing the best it can offer, replacing the skywatcher stock 10mm is probably the most commonly suggested upgrade on here.

Speaking of 'seeing' , as scarp15 said,  it might be that atmospheric conditions were poor, or maybe local factors (heat rising from buildings for example) affected the seeing. That, along with the  planet being quite low in the sky, can make higher magnifications useless . There's an outline of the problem here https://www.skyatnightmagazine.com/advice/what-is-astronomical-seeing/

Heather

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It does sound like you might not be achieving focus. That or else the seeing is just too unsteady. Also as above, take a look and see if there are any greasy marks on the glass.

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Many thanks to you all for your prompt replies.

the scope had been outside for an hour before I started gazing..

After several permutations ,I definitely used the 1.25 adapter only. In reply to scarpe15. I’ve not had one decent focus  thru the 10mm. how do I know the eye piece is not faulty?. It does not rattle when I shake it, there’s no sign of a crack.

im planning to clean the mirror and Set the collimation on Tuesday, as 2 nights of clear skies are forecast (fingers crossed)

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A successful night. I finally achieved focus (it was that simple,.I feel a complete numptie, but a good steep learning achieved )
Fascinating to see Jupiter’s belts a little nearer.

Still on the subject of eye pieces , where do I go from here regarding upgrades ?. It’s a minefield  of people’s opinions of various EPs on Flo. Obviously price is the main factor, but I’d rather have one decent one than 2 of poorer quality . Any suggestion of makes . Are barlows handy to have.

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Re cleaning the mirror, does it definitely need it? I'm no expert, but I gather that it's something you shouldn't do unless really necessary and could cause more harm than good. Your telescope will tolerate a bit of dust or dirt on the mirror as discussed in many threads on this forum. Personally, I've learnt not to look too hard at mine!

Collimation on the other hand, is something you should learn to do.

Pete

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The picture would be helpful, cleaning optics is not something to be taken lightly and often it's not needed. If you are making out details on Jupiter then I suspect it's fine as it is

Cleaning is possible at home though, you just have to be very careful and gentle, there are many good tutorials kicking around on the best way to achieve it

And don't stress about the focus thing, I have basically the same scope but with the previous Helios branding and it is definitely harder to focus at higher magnification, especially if you have the basic rack and pinion focuser the same as me, it's an art in itself ;) 

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Honestly that looks fine, mine was a hell of a lot more filthy before I even considered doing it

If you really, really must clean it, maybe grab one of these (don't wipe the mirror, most common cause of scratches) https://www.firstlightoptics.com/astronomy-optics-cleaning-protection/jumbo-silicone-hurricane-blower.html

Make sure you are happy with collimation though as you'll need to remove the primary mirror cell to be able to get at it

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On 07/09/2021 at 22:39, Orange Smartie said:

I'm a relative newbie too and I bought a few BST starguiders for my scope(s). They're not that expensive, but they are a significant step up in quality from the stock eyepieces.  

Pete

I'd second that. I'm in a similar position, maybe a step ahead of you in that I've just upgraded from the eyepieces that came with my 'scope..

The BST Starguiders (I got a 5mm, an 8mm and plan to get a 25mm when funds allow) made a very noticeable improvement and were well worth the price.

https://www.firstlightoptics.com/bst-starguider-eyepieces.html

Good luck!

 

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On 07/09/2021 at 22:36, JohnWat39765628 said:

A successful night. I finally achieved focus (it was that simple,.I feel a complete numptie, but a good steep learning achieved )
Fascinating to see Jupiter’s belts a little nearer.

Still on the subject of eye pieces , where do I go from here regarding upgrades ?. It’s a minefield  of people’s opinions of various EPs on Flo. Obviously price is the main factor, but I’d rather have one decent one than 2 of poorer quality . Any suggestion of makes . Are barlows handy to have.

My tale of eyepiece upgrades (still ongoing !) went like this : Bought a 150  heritage, loved it, used the stock ep.s , wasn't sure if my eyes with my 'scope in my back garden (this was during lockdown #1, so no chance of  trying out anyone else's ep.s) would see much improvement. So I bought a 17mm skywatcher super plossl  for £20 from a camera dealer. Why 17mm ? Well, first it was somewhere between the stock 10mm and 25mm, so if it didn't provide an improved view, it would ay east offer a different one. And second, it was £2 or £3 cheaper than the other focal lengths :blush:

It arrived, I used  it. I loved it 🙂 Sharper, brighter, obviously much better made than the stock stuff.  I soon added a 32mm skywatcher super plossl. I still use both regularly , the 17mm lives in my refractor , the 32mm gets used as a 'finder' eyepiece in any 'scope I happen to be using. I've since found that 15/16/17mm is an eyepiece focal length which works really well for me in the heritage for DSOs, and is what I use most.

Sheer beginner's luck that it was a 17mm I happened to buy first, there's plenty of technical discussion on here about how exit pupil of a setup affects the contrast between a bright background and a faint DSO in light polluted skies , I guess that may be what is going on here. I added a 12.5mm SW plossl to my set, and was underwhelmed. It was a small step up from the included 10mm , but ... meh. Not impressed, and having read of the reduced eye relief as you go lower mm in plossls , I saved some pennies and made my next purchase an 8mm BST, which was an impressive hike in quality.

The BSTs are solidly made, have big wind up eyeguards ,decent eye relief (which you need if you wear glasses , I don't, yet, but good to know ) and give a nice bright sharp 60 degree view, which is 10 deg. wider than a plossl.  I've not bought a 5mm (it would be too much mag, for my mak, and I use that rather than the dob for high mag.)  but have added BST 12mm, 15mm, 18mm and 25mm to my 8mm.  As I've said elsewhere , the only one I don't like in the heritage (which is f5, so picky on eyepieces) is the 25mm. The stars around the edges of the field do not look good (perfectly fine in the f11 mak though, it's the 25mm in combination with the heritage that's my problem. Some say the 18mm is less good than the rest, but I like mine OK, I'm probably less discriminating than many, and I'm not looking for flaws.

Because I use the 15mm BST (or 17mm plossl) so much, I had a hunt around to see if there was anything really nice to look out for , maybe second hand , in the future. I saw the 16mm Nirvana (£90 new) getting a lot of positive comment, and bought one last month. It has an 82 degree view vs the BSTs 60 deg. It is sharper, brighter, has a 'wow!' factor wide view for clusters etc, resolves more fine detail on sunspots (I've only been allowed a couple of hour's night viewing with it , thanks clouds 😞 ) . But it is double the price of the BST 15mm , and not twice as good . Don't get me wrong, it's a keeper, I'm happy with it, but as the cost of such things increases, the improvements you get for each extra £ become more marginal. I think that for what they cost (and especially if you can snaffle a good second hand version, at the moment they usually go for around £35 on here) the BSTs are a great balance between cost and quality of view. In an f5 (or lower number f ratio) 'scope, the 25mm might displease some, and a £30 32mm plossl could be a cost effective alternative.

I've spent several cloudy evenings recently researching what would be a good replacement for the 25mm BST , and dicovered the general opinion is something from the Explore Scientific range for around £150, or a Baader Morpheus for close to £200. Not amounts I can contemplate spending ! However,  I recently pounced on a well priced second hand maxvision 24mm (which I believe is an old ES eyepiece design which was rebadged to avoid stocks of it being confused with the newer design ). I'll be interested to compare it with the 25mm BST !

Heather

Edited by Tiny Clanger
clarity
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Your mirror looks fine as has been said, and if the images are good enough - then its good enough. Newtonian mirrors cause more unnecessary angst to newcommers than anything else and  I remember the horror at seeing my first mirror covered in moisture spots when it ended up with a coating of dew. But cleaning them by using tap water in a plastic bowl with detergent and fingertips followed by a rinse with distilled water works a treat - there are several guides on this forum or youtube to help you.  Comes out like new unless it is very badly corroded in the first place - you might end up with a couple of water spots which might look unsightly but they have zero effect on the view through the eyepiece. So eventually when it does need a spruce up dont be afraid to do it, just  be careful and prepare your workspace.  Try not to get the center spot too wet if you do ever go down the cleaning rabbit hole by the way - dont want it comming adrift as re-spotting a mirror is a pain - doable but you will always wonder how accurately placed the new spot is. Best advice with a newtonian is spend little time looking at it and most time looking through it.

As far as fingertips to clean the mirror surface goes -  I might be reluctant to sub contract the cleaning out to a blacksmith or bricklayer or someone who's hands are so hard an calloused through hard labour that they have fingertips like emery paper..............fortunately I am workshy so have no problem in that department.

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1 hour ago, Barry Fitz-Gerald said:

Try not to get the center spot too wet if you do ever go down the cleaning rabbit hole by the way - dont want it comming adrift as re-spotting a mirror is a pain - doable but you will always wonder how accurately placed the new spot is.

Just make a spot in the center of the donut with permanent ink or a tiny paint blob before cleaning in case that happens.  Soapy water won't generally remove either mark.

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