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Silly malnourished orange dovetail...

emadmoussa

By emadmoussa
in The Astro Lounge

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emadmoussa

emadmoussa

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I finally subjected the C11 to first light. I should take my hand off my heart, everything worked as expected. collimation was spot on and images were razor sharp.

Having owned several scopes mainly refractors, this one is my first SCT. It took me few minutes to get my head around the SCT focusing system. It's tricky since in the beginning I didn't know whether the mirror was traveling forward or backwards. Luckily I already upgraded to Revelation Superfocus SCT focuser...pretty good focuser indeed, soft as a feather and solid as a rock. Much of ''astronomical pathetic fallacy'' :)

While it blew my sucks off on my 6" refractor, the Sky-watcher Panorama 82-degree 15mm EP didn't perform impressively on the C11. Well, it's almost twice the focal length of the frac... On the other hand, the Baader Scopos 35mm felt like it was made for this scope. Actually this eyepiece complemented with a 2" heavy diagonal and 2" 2x barlow showed how solid the Revelation Superfocus focuser was. All combined came to more than 2Kg, and the focuser seemed like it couldn't give a damn how heavy the stuff was. It's supposed to handle up to 3 Kg with ease. I think I could go a bit more than that an expect the focuser to hold just fine.

OK, now over to the rubbish bit. No matter what's being said about standard mounting mechanisms. The vixen style dovetail that came with the scope is ...how to put it subtly? Well, slim malnourished orange-tanned silly stick and it sucks big time. While it can hold the telescope ''OK'' on the NEQ6, it aroused a sense of paranoia in me. Whenever the mount slewed, I had to grab the scope handle..just in case. In my head I could see the C11 coming off the mount and ending my session with a disaster. Every time the telescope moved on the dec axis, it vibrated and took a little bit of time to settle. So much of stability, huh?

I already own a Farpoint losmandy dovetail. I bought it second hand. Attaching the front radius block was a nightmare, I'm under the impression that it is slightly damaged. By the way, this one is usually on the top of the C11- barely holding. While observing I had to take it off since it added more weight to the already fatigued orange dovetail.

How much difference will it make if I replace the malnourished orange dovetail with a Farpoint or ADM losmandy dovetail (both look the same to me, aren't they?) ? Will the ADM dual saddle increase the stability of the orange dovetail?

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emadmoussa

emadmoussa

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I decided to have a play earlier. I managed to fit the Farpoint dovetail on. The little almost invisible alan bolts had caused me a headache trying to get them out. But worked evetually. I think I dropped a little nut into the tube. Now stuck somewhere behind the mirror. It doesnt move about when I move the scope. Visually the scope is fine. I wonder if I can open the back bit of the scope, dont have the heart to do it though :( or I should treat like a fragment, leave it there...if you take it out the patient will bleed to death.

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Pig

Pig

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Imad,

If the nut is not affecting anything I would leave it alone until you have to. (can you see it when you look inside?)

How is the new Revelation focuser ? :smiley:

I also thought the mounts were a little wobbly at the astronomy show, that is the reason I went for the fork mount in the end.

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emadmoussa

emadmoussa

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Yeah, I saw it in the beginning. I tipped the tube off trying to get it out through the focuser, but it went behind the mirror and stopped moving about. I just dont know how it happened..

The focuser is brilliant, even my little daughter thinks so since she couldn't lift it up to her mouth :)

The Farpoint dovetail coupled with a Farpoint 3" clamp added a lot more rigidity to the the scope. Quite happy with. I will go for an upgrade saddle as well.

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Zakalwe

Zakalwe

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Yeah, I saw it in the beginning. I tipped the tube off trying to get it out through the focuser, but it went behind the mirror and stopped moving about. I just dont know how it happened..

You won't get it out of the focuser because the baffle tube protrudes into the body of the OTA. You best bet is to take the corrector off.

If you look through the corrector you will see that the dovetail mounting points have small metal straps bolted inside the tube to reinforce the point where the dovetail mounting bolt screws in. I would think that it's likely that you have unscrewed on of the bolts that holds these plates in place, thus causing the nut to drop inside. Make sure that the plate is still secured! Although its a small piece of metal, it could do some damage to the corrector or the mirror it it drops onto them.

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emadmoussa

emadmoussa

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You won't get it out of the focuser because the baffle tube protrudes into the body of the OTA. You best bet is to take the corrector off.

If you look through the corrector you will see that the dovetail mounting points have small metal straps bolted inside the tube to reinforce the point where the dovetail mounting bolt screws in. I would think that it's likely that you have unscrewed on of the bolts that holds these plates in place, thus causing the nut to drop inside. Make sure that the plate is still secured! Although its a small piece of metal, it could do some damage to the corrector or the mirror it it drops onto them.

Yep, I think this is what happened. It seems stuck and immovable somewhere behind the mirror plate now. So I'm not particularly worried.

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glowjet

glowjet

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"Yep, I think this is what happened. It seems stuck and immovable somewhere behind the mirror plate now. So I'm not particularly worried. "

Emad, you may think it is stuck now, but these things have a nasty habit of coming loose again, when you least expect it. If I was faced with your particular problem, I would certainly try to get the nut out for peace of mind, because If by chance during handling, it does come loose and causes some damage to your mirror or plate, I could imagine Emad is not going to be well pleased :)

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barkis

barkis

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As long as you don't invert the tube at any time. Too far and the little blighter will decide to reappear, drop down the tube after colliding with the baffle, slide down that,

and smack the secondary in the eye.

It might be small that little runt, but it could mark the mirror surface. Then, in haste your right the tube, and behold, it sets off on another journey,

colliding with the main mirror this time, leaving another small scar behind.

You will hold your head in your hands, and mutter, Why did I not make the effort to get the blighter outta there :grin: .

Ron.

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m.tweedy

m.tweedy

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ashas been said when the scope is being moved/slewing etc you could end up with a nasty surprise.

here is a link to removal of a corrector plate. it talks about a C8 but applies just the same to your scope.

http://aquillam.wordpress.com/2012/02/29/c8-repair-removing-the-corrector/

you may then have to move the mirror up the tube slightly by moving the focuser to dislodge the nut.

is there not a local astro society that could help.

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Helen

Helen

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If you can get it loose you could try a small magnet on a piece of string through the eyepiece hole to pull it out.

Failing that, taking the corrector off isn't as scary as it seems, I've done it on a c8 and a c11.

Helen

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Zakalwe

Zakalwe

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If you can get it loose you could try a small magnet on a piece of string through the eyepiece hole to pull it out.

Dont forget the loooong baffle tube...

Just another thought..... is your C11 fastar compatible? If so, you can just remove the secondary rather than removing the corrector...

IIRC, removing the secondary still leaves the secondary baffle attached to the corrector. That'd make extraction very difficult.

Removing the corrector is the best option. it's not that big of a job as long as you mark it and take your time.

The nut isn't going the stay behind the mirror. Even if it does, I'd be concerned that it would foul the mirror when the mirror is racked the whole way back (nightmare thoughts of it jamming the mirror!). It needs to come out, one way or another.

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emadmoussa

emadmoussa

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I'm bemused at how that nut got there in the first place. What were you doing that let to it falling down the tube?

I think that happened while trying to fit to Losmandy dovetail...probably unscrewed the wrong screw ending with the nut falling off.

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E621Keith

E621Keith

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I thought bolts thread directly into threaded holds in the SCT front and back casing. It's worrying to hear there are nuts inside that can come loose.

I would remove the corrector and possibly the primary to retrieve the loose nut. You don't want it to come loose and then fall onto the primary or the corrector when you are handling it. Since you will have to disassemble the SCT anyway, you might well get some flocking materials and flock the tube as well.

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emadmoussa

emadmoussa

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I thought bolts thread directly into threaded holds in the SCT front and back casing. It's worrying to hear there are nuts inside that can come loose.

I would remove the corrector and possibly the primary to retrieve the loose nut. You don't want it to come loose and then fall onto the primary or the corrector when you are handling it. Since you will have to disassemble the SCT anyway, you might well get some flocking materials and flock the tube as well.

I'm barely disassembling. I will take the corrector plate off and just tip off the telescope trying to shake the nut off and get it to fall down . I don't really see what the big deal about flocking is anyway...what advantages does it give you if you're not mainly imaging?

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