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I think I screwed up !

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#151 Cenk

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Posted 11 February 2008 - 04:35 PM

Do you get crisp images at that level of magnification though ?

#152 qqmtl

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Posted 11 February 2008 - 05:11 PM

Hi Cenk I had the same problem when focusing and the solution was the Celestron Motofocus now the retail value is around 150$

Thx

#153 Starlighter

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Posted 11 February 2008 - 07:25 PM

Do you get crisp images at that level of magnification though ?


It all depends what seeing conditions happen to be. Where I live there are these thermals that come from the nearby mountains and wreak havoc with what I'm trying to view. Sometimes they calm down enough to use high magnification, but other times there's so much turbulence that whatever I'm looking at appears to be under a shallow running stream. I sat out one night when Mars was closest to Earth peering into the scope waiting for a clear moment. After what seemed like hours it came briefly allowing me to see the polar cap and some darker patches, but then as quickly as it cleared, it became lousy again. Last night I tried looking at Saturn. About a week ago I had one moment when it looked terrific at high power. Last night wasn't one of those nights. Saturn rippled and bubbled and looked awful. I had to revert to low power.

#154 Plan9

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Posted 11 February 2008 - 09:18 PM

Do you find that the focuser is a little difficult to get right at high magnifications ? Do you get sharp views of Saturn/Jupiter/Mars at high magnification ? With an 8mm Televue Plossl my views of Mars/Saturn are fairly dull and looked unfocused.

Just had to jump in here - this was the substance of my first post to the cats and casses group. The short answer to your question is that anywhere shorter than my 13mm eyepiece (remember, I've got the 6SE as well), the views were unimpressive and I felt I couldn't find focus. I really think this has been a combination of bad seeing and cold (and dropping) temperatures. I had a great evening a few days ago where things looked sharper (a 9mm was acceptable on Mars, but still not much detail). I believe that the collimation is ever so slightly off from looking at defocused stars, but I'm not ready to tackle that yet. At lower mags, on stars, clusters, nebulae, it was just brilliant. Also, for some reason, alignment and tracking were exceptional too.

Bill

#155 Cenk

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Posted 12 February 2008 - 03:01 AM

Yes I wondered if it could be atmospheric conditions. I will learn patience. One day. On another note, I found a secondhand Nexstar 8i Special Edition, I quite fancy the bigger aperture and it is on at a reasonable price. Would this fit without modification on my SE mount ? Anyone know ?

#156 Starlighter

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Posted 12 February 2008 - 12:25 PM

If it has the proper dovetail, the answer is yes. We have the same robust mount as the 8SE. It'll handle the 8i tube.

#157 Cenk

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Posted 12 February 2008 - 03:44 PM

What would anyone here pay for a 8" OTA ? I got a couple of offers on the table, as you can't buy these exact OTA's from a shop, I cannot compare with new price. I got two on offer which are both roughly 1 year old. And they are from the US.

#158 osbourne one-nil

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Posted 12 February 2008 - 04:27 PM

You can by the OTA in the UK, or something very similar.

http://www.celestron...CategoryID=3891

#159 Cenk

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Posted 12 February 2008 - 05:33 PM

Yep, I had seen that. For £1000 I can buy the scope again !!! I think those OTA's are better/different ones to the SE's. Not sure.

#160 Cenk

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Posted 12 February 2008 - 05:47 PM

Starlighter, What do you mean by proper dovetail ? How can I find out ? thanks.

#161 Starlighter

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Posted 12 February 2008 - 06:14 PM

I just mean one that fits the proper Vixen dovetail design. I wouldn't worry. The dovetail on the side of any Celestron SCT OTA will work.

#162 Cenk

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Posted 12 February 2008 - 06:16 PM

So you reckon a 8i Special Edition will go fine on my 6SE mount ?

#163 Cenk

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Posted 13 February 2008 - 02:19 PM

I just realised that my OTA was upside down on my mount. Do you guys think that this could have caused all my alignment problems ??? :foreheadslap:

#164 Starlighter

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Posted 13 February 2008 - 03:15 PM

So you reckon a 8i Special Edition will go fine on my 6SE mount ?


It should work. The tube will be bigger so you'll have to slide it so the diagonal doesn't bottom out when the scope is pointed towards zenith.

#165 mojo2

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Posted 13 February 2008 - 05:31 PM

what do you mean by up side down....???? front facing where the back should have been?

#166 Cenk

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Posted 13 February 2008 - 05:47 PM

Imagine your OTA as it is now, corrector plate pointing up, dovetail in line with hand controller etc. rotate by 180degrees. weird.

#167 Starlighter

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Posted 13 February 2008 - 06:12 PM

You mean you installed the tube so the arm is on the right as you're looking into the eyepiece along with the RDF being underneath? That would mean the Celestron 6SE on the dovetail is upside-down and that's not what I see in the photo you posted. Please explain. :question:

#168 Cenk

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Posted 13 February 2008 - 06:22 PM

It was. but the ALT/AZ was moved around so it appeared the right way up. The only way to tell was that the dovetail wasn't really flush against the mount when it was the wrong way. Does that make sense ?

#169 THEPLOUGH

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Posted 13 February 2008 - 06:51 PM

NO. NO, NO.... :confused:

#170 Cenk

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Posted 13 February 2008 - 06:58 PM

I would draw a picture, but last time everyone laughed at my artistic skills.

Imaging your mount and your OTA. Simply rotate it by 180degrees. See what I mean then. The Celestron writing will be right way up again if you use the controller and rotate the OTA on the ALT axis.

#171 b1gred

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Posted 13 February 2008 - 08:35 PM

Take a picture and post it...?

#172 Fred1

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Posted 13 February 2008 - 10:50 PM

I thought the 6SE and 8SE had the same mount. So shouldn't they mount the same way? Also, if we're talking about the 8i wouldn't that need a Ray's Bracket to mount it on an SE mount?

#173 Cenk

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Posted 14 February 2008 - 03:17 AM

Fred, I was meaning my existing 6SE. Good info on the Bracket I may need for the 8SI though. Thanks. Here are the photos, hopefully that will explain:

This is how the scope is now, corrected.
Posted Image

This is turned around, off mount and turn 180 degress
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Now I just move the mount, to turn the scope all the way back, so it appears correct, you can see the tightening bolt is now facing up
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Now put it in the correct way up again by taking it off and rotating 180degrees, fits completely flush when this way around as opposed to slightly raised when wrong. The secondary holder gets in the way when wrong way.
Posted Image

Close up to show that the little align arrows now meet, to prove it's the right way up
Posted Image

#174 mojo2

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Posted 14 February 2008 - 06:28 AM

OOOOKAY, now i understand, it had nothing to do with the scope itself (OTA), it was the stand/GOTO directional arm! That was weird. You must have inserted it the wrong way on initial setup when you got the scope.
I have no idea if that would mess alignment up or not. But, My opinion is it would have caused tons of trouble because of electronic orientation in the systems memory.

I would have had no idea it should have been any other way either if it was my first scope! Glad mine was set up right.

Good catch!

#175 Cenk

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Posted 14 February 2008 - 01:32 PM

Yes. I am glad I found it. I havent been able to try since the change as it has been cloudy. Forecast is good for the weekend again. Will try and report back.


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