RASA 11 issue

[tich]

Hi everyone I've recently acquired a RASA 11 V1 which has an issue & I were wondering if there is anyone that can repair it? I've contacted Celestron but I've heard nothing at all from them. The issue is the Lens group has come loose in the corrector & needs to be tightened back up plus I'm guessing the collimation will need to be redone afterwards as being F2.2 I would imagine it is pretty sensitive. Someone on cloudy nights managed to tighten theirs but the post they put up is rather sketchy & doesn't really help much.
The CGE pro pictured needs repairing to but that can wait as if I cannot get the scope fixed then there's no point continuing with the mount.

[Adam J]

Yes it will be extreamly sensitive. Did you know of this issue when you purchased it, assuming its used?

Adam

[Davey-T]

Hi Tich, Mr Ackerman the co designer of the RASA is a CN member, maybe send him a PM, I know he has responded to folk in the past

Dave

Edited August 20, 2020 by Davey-T

[newbie alert]

Celestron have a 2 year warrenty.. if you bought it new and under the warranty period contact the person you purchased it from and send it back, celestron won't send you parts etc, it has to be done through the supplier.. supprised you not got a response thou, normally pretty good at replies.. Lee normally responds within a day,  did you raise a ticket?

 

[tich]

I got the scope used & knew the RASA had issues & as it's a version one it's very unlikely it has any warranty left, I raised a ticket with Celestron.com but I've heard nothing back from them, I don't know if any dealers would take it on & get it repaired for me as it seems you have to get repairs done via dealers as David Hinds mentioned this when I enquired about getting the mount repaired. Obviously I'd like to get the scope done first if it's possible before starting on the mount as my mount in the obsy will handle it but only just. 
I'm not a member of Cloudy Nights Dave so may have to join up if I don't get any joy soon as I'm keen to get these jobs done if its possible of course.

[ollypenrice]

Have you tried David Hinds directly?

Olly

[Adam J]

I think in this modern world we should expect manufacturers for fix (for a fee) scopes that are second hand and out of warrenty. Imagin if you could not get someone to fix your second hand car....all just adds to the throw away society.

Adam

Edited August 20, 2020 by Adam J

[tich]

15 minutes ago, ollypenrice said:

Have you tried David Hinds directly?

Olly

I have Olly & they told me to contact Celestron direct to get the scope looked at so I have a ticket on there that's been unanswered, the mount they said they could fix but I'd have to go through a supplier for them to raise a ticket as I'd have to pay them & not David Hinds direct. 
I can deliver the kit to them direct as I'm only about an hours drive away but I don't know why I'd need to go through a supplier & not deal with them.

[ollypenrice]

8 hours ago, tich said:

I have Olly & they told me to contact Celestron direct to get the scope looked at so I have a ticket on there that's been unanswered, the mount they said they could fix but I'd have to go through a supplier for them to raise a ticket as I'd have to pay them & not David Hinds direct. 
I can deliver the kit to them direct as I'm only about an hours drive away but I don't know why I'd need to go through a supplier & not deal with them.

An absurd situation. I hope you get it sorted.

Olly

[x6gas]

I’m not very familiar with the RASA but the secondary holder on my Edge 11 became loose (it was possibly always loose and I just hadn’t noticed...). It wasn’t too hard a job to carefully remove the corrector plate and tighten the secondary carrier - I took this opportunity to flock the scope at the same time...) I’ve never been sure that the secondary is in the factory position - some resources say it doesn’t really matter and the scope collimates well confirmed with star tests. 
 

So I wonder if the same principle applies. Obviously a world of difference between f/10 and f/2.2 but if it’s knackered already you can’t make it any worse!  
 

What are the symptoms of the problem you are having optically or is it just that it is loose?

cheers, Ian

[inFINNity Deck]

Hi Tich,

Celestron does send parts and does do repairs (and they normally are quite communicative). Last year I received new vent-covers for my 11" EdgeHD SCT and later on I shipped the SCT to them to have mirror-flop repaired. That, however, turned out to become a huge disappointment as I explain in this article on a Dutch forum (it translates well when opened with Chrome). They do not disclose any technical information, not even regarding the repair, but especially their final remark ("I am sorry about the issues you experienced") after I found out that nothing had changed (apart from a big hole in my pocket) I found rather disappointing.

Nicolàs

[tich]

32 minutes ago, x6gas said:

I’m not very familiar with the RASA but the secondary holder on my Edge 11 became loose (it was possibly always loose and I just hadn’t noticed...). It wasn’t too hard a job to carefully remove the corrector plate and tighten the secondary carrier - I took this opportunity to flock the scope at the same time...) I’ve never been sure that the secondary is in the factory position - some resources say it doesn’t really matter and the scope collimates well confirmed with star tests. 
 

So I wonder if the same principle applies. Obviously a world of difference between f/10 and f/2.2 but if it’s knackered already you can’t make it any worse!  
 

What are the symptoms of the problem you are having optically or is it just that it is loose?

cheers, Ian

I haven't actually tested it yet Ian but with a loose lens group you can feel slight play between that & the corrector plate so I would imagine the star field would end up being quite a mess, I have looked at it & there doesn't seem any obvious way to tighten it so I'm guessing specialised tools are going to be needed to do it.

[fwm891]

@tich Have you down loaded the Celestron RASA White paper on the 11". On page 24? there is a schematic of the lens / corrector assembly which may help you. It's  dealing with customised adapters for the rasa when their supplied ones don't fit your camera. It looks very much like a screw threaded ring.

Link to the paper in my drop box: https://www.dropbox.com/sh/2tjwfmjwydczggf/AACfdFkUjxEo7glVbN1O80OOa?dl=0

[tich]

Wow that is very disappointing Nicolàs not very good service at all which is kinda worrying, I've downloaded the white paper Francis the threaded ring is what the camera is held on by I think that's what you mean it's the to halves that are on the corrector plate itself that are slightly loose that's the issue sounds an easy enough fix but it appears it isn't.

[x6gas]

1 hour ago, tich said:

I haven't actually tested it yet Ian but with a loose lens group you can feel slight play between that & the corrector plate so I would imagine the star field would end up being quite a mess, I have looked at it & there doesn't seem any obvious way to tighten it so I'm guessing specialised tools are going to be needed to do it.

Fair enough but that would definitely lead me to removing the corrector plate and getting a look at the back end of the lens group.  I couldn't see the screw thread that Francis was referring to on the schematic but that would match what Celestron have done on other scopes. 

[inFINNity Deck]

Please note that there are two type of RASAs (old and new model), so yours may differ from the drawing.

Nicolàs

 

[fwm891]

The threaded parts I've arrowed in red. The red part is the ring that any adapter is held against. The grey areas I've indicated as A and A' are the collars that sit each side of the corrector plate. Undoing the red collar will (looks like) release the lens assembly and this is probably the collar that needs tightening to reset the lens assembly against the collars A & A'

I've added a second drawing from the Celestron White paper which shows the whole lens assmbly in the corrector. I think this shows that the red collar is the unit that tightens the lens assembly in place against the corrector plate collars. Hope this helps.

That's how I read the Celestron drawings.

Edited August 21, 2020 by fwm891
Image and text added

[newbie alert]

21 hours ago, tich said:

I got the scope used & knew the RASA had issues & as it's a version one it's very unlikely it has any warranty left, I raised a ticket with Celestron.com but I've heard nothing back from them, I don't know if any dealers would take it on & get it repaired for me as it seems you have to get repairs done via dealers as David Hinds mentioned this when I enquired about getting the mount repaired. Obviously I'd like to get the scope done first if it's possible before starting on the mount as my mount in the obsy will handle it but only just. 
I'm not a member of Cloudy Nights Dave so may have to join up if I don't get any joy soon as I'm keen to get these jobs done if its possible of course.

David hinds is the celestron distributor for the UK, yes they do repairs but fussy  and claim to only deal with the celestron dealers... they was willing to sell me a handset but when it transpired that it was the board they wanted the whole mount posted to them, through a dealer but wasn't taking on any repairs because of covid.. didn't help me to find a distributer as my nearest had closed so I had find and message tring ,said they would do it but David hinds wouldn't give them a price until they had seen the mount.. which they wasn't taking in any repairs! So I got a second-hand board  and then fixed it myself..So peeved with them I bought a ioptron cem60, the cgem is still stood in the corner sulking..

Sorry, went off topic there...

Maybe contact Steve Collingwood from SCtelescopes , he has a optical bench, does repairs etc, worth a call and a really nice  knowledgeable bloke.. but not so sure that he does RASA design thou

http://sctelescopes.com/

[Davey-T]

1 hour ago, newbie alert said:

Maybe contact Steve Collingwood from SCtelescopes , he has a optical bench, does repairs etc, worth a call and a really nice  knowledgeable bloke.. but not so sure that he does RASA design thou

I think Steve has pretty much stopped doing repairs to concentrate on Pulsar Domes.

Dave

[newbie alert]

10 hours ago, Davey-T said:

I think Steve has pretty much stopped doing repairs to concentrate on Pulsar Domes.

Dave

Has he, that's a shame 

[tich]

Maybe that's why I'm not getting any replies from Celestron due to the Covid situation?
 I did remove the corrector plate rather nervously & try as hard as I can neither halves will tighten onto the corrector plate so it looks like I may have to wait for a bit. There seems to be a ring with 2 holes opposite each other & I'd hazzard a guess that's what needs to be tightened back up, but without having anything here that would remotely fit it I think I'll leave it to the guys who know what they're doing.

[Nigella Bryant]

Are these the kind of things that would undo the securing plate. I use these myself on optical rings. You can get them from Amazon. A stainless Steel Lens Spanner Wrench Range Repair Tool

Edited August 26, 2020 by Nigella Bryant
More comment added

[ollypenrice]

21 minutes ago, Nigella Bryant said:

Are these the kind of things that would undo the securing plate. I use these myself on optical rings. You can get them from Amazon. A stainless Steel Lens Spanner Wrench Range Repair Tool

I must buy one of those. Thanks for the information. At present I tend to use two nails clamped in a vice with a trial-and-error separation. That might just be an improvement!

🤣lly

[tomato]

That’s the tool you need to undo the retaining rings without any drama.

However, if you have removed the corrector plate you might now require specialist equipment to collimate the scope when it’s all back together, following my reading of the manual that came with my newly purchased RASA 8.

My advice, although it looks like involving a frustrating wait, is to progress a repair through Celestron. 

[tomato]

5 minutes ago, ollypenrice said:

I must buy one of those. Thanks for the information. At present I tend to use two nails clamped in a vice with a trial-and-error separation. That might just be an improvement!

🤣lly

I’m only an amateur self taught engineer, but one thing I have learnt is you absolutely cannot beat having the correct tool for the job.