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Wobbly Celestron 8SE


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Hi,

I know, I was warned about it, and I have only managed one viewing session with the 10mm eyepiece I bought since the weather turned to constant rain and now snow, but the wobble in that one session made doing anything very difficult indeed. :D

I wasn't sure if it was focussed or not, as when ever I even breathed near the eyepiece or focus knob it turned to wobble hell. I'm seriously wondering if I would just be better off getting an EQ5 or HEQ5 (6 is a bit over my budget for a mount, I think) for sanity sake (I had this in my long term plan anyway, but may just have to bring it forward a tad). The star I tried focussing on did not look like a round blob, it was like an exterior light when viewed through a wet window - what does that mean?

I've had so few opportunities to get in a decent few hour's viewing since buying what was my first telescope in October, it's trying my patience. I've had to put the telescope to one side and try to get on with something else. *sigh*

Sorry for the rant!

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Hi Johnathan - was it the view wobbling or the scope/tripod?

It definitely sounds like you were out of focus. Turn the focuser knob slowly though it's whole range and you should find the focus point somewhere. If you don't then it may need collimating.

Even if the scope and tripod are steady the view can appear to wobble due to the atmosphere. It depends on the elevation of the scope and the effects of the atmosphere (or "seeing" conditions").

Is there a local astro soc you could join where someone can show you how to get the optimal setup? You could also do with a lower power eye piece to start with - maybe a 20mm or 25mm :D

Edited by brantuk
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Hi,

I do have a 25mm which I normally start off with, but it's difficult to do the Sky Align precisely with that so I tend to switch between that and the 10mm. I've just had so little time with the telescope I'm just a little annoyed that what time I have had has not been terribly productive.

When I looked through the eyepiece without touching anything it was quite steady, but if I pressed my glasses up to the eyepiece it would wobble a little (freezing temperatures and my incidental breath on the eyepiece glass also didn't help!), touching the mount or the focus knob sent it into wobble hell. I do know what you mean though - there is a heat haze coming off the house which I will always see when viewing Jupiter at this time of year, I'll have to get to the top of the hill away from the village to avoid this but I'm waiting for better weather.

Edited by jonathan
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My C8 is mounted on an EQ6 along with a ED 80 and various finders, cameras etc. It is as solid as a rock. I do think an EQ5 would handle your scope OK.

This is exactly the kind of set up I have in my mind - a nice SkyWatcher 80ED Pro for experiments in photography and the 8SE mainly for visual. Can the EQ6 be purchased without any of the goto stuff, just basic motor drive for tracking?

The Goto mount might be perfectly fine with an 80ED on it, I shouldn't be too hasty in selling the thing just because of early inexperienced blues.

Edited by jonathan
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Whilst I agree that the EQ5 would be better,I think you should persevere with the Nextstar mount .I now use 2in eyepieces with mine and have no difficulty with alignment using a 40mm eyepiece - higher magnification is more accurate - but mine goes to nominated objects OK Is the 'wobble' an out of focus effect or do you mean that the image wobbles, ie moves?

Old Codger

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I certainly sympathize with you having a mount that is not up to the job. I was given a 4" reflector to observe with which sat on top of a flimsy mount and trying to get focus whilst at the same time trying to keep the object in view was impossible. The whole exercise was like starring in an earthquake movie, even thinking about focusing set the whole thing off. But as part of my equipment investment, I then purchased an NEQ6 mount upon which I attached the very same scope. Talk about going from one extreme to another because although the scope is limited in what it could see, the fact that I was now able to squeeze the last bit of focus out of an object because it was now attached to a rock provided a completely different viewing experience. There must be loads of little scopes out there that are fine to look at the moon but fail because of those cheap inefficient mounts. I would certainly recommend getting a better mount and as brantuk suggests, a 20mm-25mm eyepiece to work your way in to the final focusing in on an object.

Wishing you clear skies soon

James

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Whilst I agree that the EQ5 would be better,I think you should persevere with the Nextstar mount .I now use 2in eyepieces with mine and have no difficulty with alignment using a 40mm eyepiece - higher magnification is more accurate - but mine goes to nominated objects OK Is the 'wobble' an out of focus effect or do you mean that the image wobbles, ie moves?

Old Codger

It moves (shakes, vibrates) when ever I try to focus it (very noticeably when using the 10mm). I can look through the eyepiece with my hands behind my back and the view does not move. A 2" diagonal and 38mm eyepiece is on my shopping list... time to buy before the VAT goes up maybe?

I suppose the SkyAlign might be rendered slightly inaccurate by using a 10mm eyepiece, as the objects move so fast in it that by the time I've got it in sight and pressed the Align button it's probably far from centre. I also noticed that it did not keep objects in the eyepiece, I thought that it was supposed to track constantly (it makes a quiet whirring sound all the time), maybe that's something that needs fine tuning. I am running on a 12v 5-in-1 power tank so power shouldn't be the problem.

Edited by jonathan
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So it's definitely the rig vibrating. It's a pity cos the 8SE optics are smashing but a one sided fork allways seems a poor idea to me. Best thing I can suggest is to ensure all the attachment points are firmly connected.

I.e. tube to fork, fork to tripod, tripod legs locked firmly, etc. If there is any movement anywhere at those points they'll reflect in the view when you touch the scope. Ensure the altitude mechanism and azimuth movement are smooth with no undue lateral movements.

Even there's likely to be a little settling down period required after slewing (only a few seconds though). I try to look through any scope without actually touching it anywhere. You could try "Damping Pads" for the tripod feet - might make a small difference.

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The Celestron single arm fork is imo a bit ambitious for an 8" scope even 6" to be honest.

What I can say though is buy an EQ6, dont get the synscan option go for a Syntrek and EQmod it.

It will last you and opens up options.

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So it's definitely the rig vibrating. It's a pity cos the 8SE optics are smashing but a one sided fork allways seems a poor idea to me. Best thing I can suggest is to ensure all the attachment points are firmly connected.

Yes, I would agree about the single fork arm. I need to give it some more time, perhaps there are several things I can fine tune and tighten up to make it better, but ultimately I think it's going to be an EQ5 or EQ6 for me. Just have to wait for some clear weather.

We live and learn, I learn by doing.

Thanks all for the advice. :D

Edited by jonathan
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The Celestron single arm fork is imo a bit ambitious for an 8" scope even 6" to be honest.

What I can say though is buy an EQ6, dont get the synscan option go for a Syntrek and EQmod it.

It will last you and opens up options.

I did a quick online search for EQMod - is this only something I would need if I wanted Goto? I take it I would need to hook up a laptop to the mount in order to use it, that may be something for the future but at the moment I just want to see some stars...

Edited by jonathan
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I use the 8SE and while it does wobble a bit during focusing, it settles down after 2-3 seconds. Make sure that the leg spreader is engaged with all 3 legs - I find that some times I have to pull the legs apart fully to get it lined up.

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I was given as a birthday present by my son a set of Celestron vibration suppression pads. I tested them tonight for the first time and they have really helped a great deal wobble is now down to 1-2 from 5-6 seconds previously, and even if i accidently touch the eyepiece with my forehead it doesnt wobble! I only have an old 8 inch SCT on a fork mount and its on the basic wedgepod tripod base. These pads have certainly fixed the problem i was having with the wobbles! i know their expensive but maybe Santa could send you some?

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I was given as a birthday present by my son a set of Celestron vibration suppression pads. I tested them tonight for the first time and they have really helped a great deal wobble is now down to 1-2 from 5-6 seconds previously, and even if i accidently touch the eyepiece with my forehead it doesnt wobble! I only have an old 8 inch SCT on a fork mount and its on the basic wedgepod tripod base. These pads have certainly fixed the problem i was having with the wobbles! i know their expensive but maybe Santa could send you some?

Hmm, I'm dubious as to how these would help my current situation as our garden is quite uneven and the ground usually soft, the tripod legs tend to stick in it like a set of football boot studs.

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Hmmmm..... soft ground isn't allways a good idea as sinking can cause small alignment errors.

I'd put a small patio slab under each foot to spread the weight (those little 12" square ones) and add in the vibration pads. If that's not enough try anchoring the tripod by slinging the field battery under it in a rope bag or something similar. :D

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Ditto Brantuk. Use small slabs and the anti vibe pads.

However, you can't expect to be touching a telescope while looking through it, other than to focus. It is tricky even with a good solid mount, let alone an oxymoron. (Single armed fork!!!) A very good trick is to sit down. You see far more when comfortable on a stool. Believe me, this matters.

The wide field EP should be plenty good enough for alignment if you put the star in the middle. You only have to get within finding distance then buzz EW or NS to get to the target. I suspect the soft ground is letting the mount move.

Olly

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Hmm, well I'm afraid I can't really get away from the soft ground unless it's either frozen solid or dry as a bone (it's neither at the moment - too much snow on the ground to even see it!)

Patio slabs, that sounds rather drastic (and heavy) to be lugging up the garden each time, let alone to a remote site. That is very likely to put me off observing all together.

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The small ones would be ok (they're either a foot square or 9" square and quite light) - you can place them on the ground and mark where the tripod feet go when set up - just leave them there to make it easier setting up the next time. :)

Edited by brantuk
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if you go to a motorcycle store, or look online, you can get little coaster size plastic trays that stop the bike stand stinking into soft ground, weight hardly anything and would rule out the sinking problems?

They stop my 600lb plus bike sinking on a single support so would have no problem with a tripod and mount, pretty much however big it was!

Edited by Trevor-Austin
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