Celestron C8

[Virgoman]

Hi all,

I happened to find the following on OPT`s ( a highly respected optics supplier) website in the US today. As follows:-

OPT PAT for Celestron C8-SGT - 8" SCT on CG-5GT Mount

• Let our Telescope Technican set-up and test your new telescope.
  
• If it doesn't pass muster, it doesn't ship!
  
• Includes a written report showing test results.
  
• A Shockwatch label will be attached to all tested telescopes, assuring careful handling during shipment and delivery.
  

Our exclusive Performance Assurance Testing (PAT) program was created in 2002 due to overwhelming demand. Our customers regularly requested that we open their telescope and run it through it's paces, just to make sure everything was as it should be, but until we started the PAT program, it just wasn't feasible. Although the majority of telescopes manufactured by our most popular vendors are just fine right out of the box (as they should be), a growing number of amateur astronomers like to have extra assurance...and that is what a PAT provides our customers.

Its the bit " telescopes manufactured by our most popular vendors are just fine right out of the box (as they should be) " that I find interesting and applicable in my case. Customer is truly king in the US? The ironic thing is I paid extra for delivery, as I am outside GB mainland, ( If I didn`t pay - no delivery) for a telescope with collimation miles out - as Brian says. Seems we just have to put up with it? I even remember when I was purchasing this scope that I asked was the collimation checked before dispatch. I was told that the boxes were factory sealed and customers preferred that... I also note OPT`s use of a Shockwatch Label for shipping. I received a Tal 100r from Bray Imaging 7 years ago and a Shockwatch label was fitted. Why aren`t these used more often in transporting delicate optics?

Kind regards,

Ralph

[brianb]

I even remember when I was purchasing this scope that I asked was the collimation checked before dispatch. I was told that the boxes were factory sealed and customers preferred that...

Facts of the matter seem to be:

1. Celestron factory does a reasonably good job of collimating scopes. My CPC1100 was within a hair of perfect on receipt (of a factory sealed box, transported from China to Northern Ireland by God alone knows what route) and I think this is pretty much par for the course.

2. OTOH rough handling in transit can and apparently does sometimes cause the collimation to be way out on receipt. This could still happen even if the "local" dealer checked and corrected the collimation before shipping it to you. Use of a Shockwatch Label might help reduce this - if you were to reject delivery of a "shocked" package - but the end user price would undoubtedly rise to compensate for the extra cost of returns of equipment which was undamaged but might require to be adjusted. And the damage that might occur during unnecessary return shipments.

3. Collimation is a routine user maintainance procedure. It's not as though the task of collimating a SCT requires any expensive or unusual tools, they even pack the hex key that you do need.

[Virgoman]

Thanks for the reply Brian, it is much appreciated. I think I am just a bit frustrated at the moment and a bit miffed that mine turned up so far out of collimation. I have never had to collimate anything before having owned a Mak and refractors which always "worked" right away. I just didn`t expect having to fiddle with a new scope.

Have you ever received a new scope that has required collimation immediately? It would appear that I have been very unlucky then -be that down to Citylink or not.

There is also always the worry that you have ended up with something that is going to give problems.

Is your corrector adjusted by a Hex key? Mine are Philips heads - and no screwdriver was supplied, although there are Hex keys supplied. What do you think of Bobs Knobs? They are supposed to make collimation easier plus they eliminate the risk of fiddling around with a screwdriver.

[brianb]

Have you ever received a new scope that has required collimation immediately?

Yes. Including a refractor and a Mak which did not have provision for user correction of the collimation. Neither was far off, but it was enough to spoil the high power view.

My Meade LX90 8" was miles out of collimation when delivered. It took a few goes to get it right. And the optics were noticeably less sharp than those in my CPC1100, even when cooled to ambient, the seeing was as good as it gets and the collimation was done as accurately as I could manage.

You're right about the collimation screws - mine are cross head too. Shows how often I've needed to touch them. The plastic cover has been off once, the first time I got decent seeing, for the purpose of checking the collimation - I needed to adjust one of the screws about two degrees. Since then I've always found the collimation to be "near enough" when checked with the diffraction pattern just inside & just outside focus, & I think my images show this assessment to be accurate. The Meade had hex bolt adjusters, & I still associate "collimating an SCT" with that.

Bob's Knobs sound like a good idea but fitting them is guaranteed to wreck the collimation (however carefully you do it) and some people report that the scope doesn't hold collimation as well after fitting them. Personally I'd leave alone. They may make collimation more convenient physically - especially with an 8" or smaller tube, where may be feasible to do the job by reaching round the front of the tube whilst still looking through the eyepiece - but they certainly will not make it easier to get the adjustment right.

[Space Bat]

Hmmm!!

The corrector isn't always aligned as well as it should be...

Even if the markings suggest they are in sync....

They always required fine tuning in the late 80's early 90's my involvement in these scopes ended then, until now...and guess they are using lasers and more fancy equipment to set them up..but like all things probably needs human intervention to say yes/no or it's good enough...as ever good enough tends to be the scopes that cause problems.

Having said that....you would have to know what to look for as it was very subtle and the majority wouldn't know the difference unless seen side by side.

Looking at the image - hard to tell what's up...

If you're not happy suggest sending it back for evaluation....

Chris

[Virgoman]

Thanks for the replies guys. I will wait and try to get a few images. Hopefully all will be well or I may be forced into, as suggested by you, Spacebat an evaluation or exchange. This is were customer support comes in......

Ralph

[Virgoman]

Hi all,

Hope everything is O.K. Just a quick update on my C8 problem. I contacted D. Hinds and enclosed photographs of the deposit inside the plate. On their instruction the scope was returned for examination. Upshot is there is indeed a problem with the corrector plate and well done, dweller25 it appears there has indeed been some outgassing onto the optics. Probably should never have left the factory? I received a call from Chris today and he has replaced the corrector plate. Apparently after the material had been cleaned off the coatings still exhibited some blotching, so a replacement corrector plate has been fitted. He also oblingingly collimated the optics so.........hopefully I will be up and running in a few days!!!:hello2:Let`s hear it .......yippee! I hope to receive the scope early next week....probably to coincide with Rubbish weather. Seeing all those wonderful Mars images has been very frustrating and its getting smaller....ah well at least there`s Saturn.

All the best,

Ralph

[davew]

Hi Ralph,

A lesson to us all. If it looks wrong it probably is wrong.

Well done. I don't have a C8 myself but when I've looked through one at a dark site I can see the appeal.

Dave.

[MartinB]

Ralph, sorry to arrive at this discussion so late. I am so glad you have the problem sorted. It is a miserable thing to invest a lot of money and be disappointed. I can assure you you won't be when you get it back. I used to own an 8" Nextar and it was a superb scope. With everything I ever looked at it outperformed my ED120 by some distance. The only time the ED120 managed to match it was in poor seeing on planets and the moon when it had a wee bit of extra contrast. Stars were beautifully tight right to the edge using a 30mm Moonfish UWA

Once you get it onto DSOs you will certainly notice the benefit of the extra aperture compared with your ETX.

When I received my 10" LX200R it was massively out of collimation. It is hard collimating an SCT when it is so far out that you just get a V rather than offset rings. Having collimated it, it just stays collimated. Well it did on a trip back from Kelling, the following year and then back to Kelling again, so I'm sure it wasn't factory collimated.

Please give us a progress report when you get the scope back

[Virgoman]

Thanks for the replies Martin & Dave. Very much appreciated. I am looking forward to using it in anger and will be happy to give a progress report. As an aside can someone recommend a suitable anti dewing system. Experience has shown that a dew shield has been of limited value.

Kind regards,

Ralph

[Virgoman]

PS Martin, just had a look at your DSO and planetary albums. Absolutely stunning. Something to aspire to. Top class.

Kind Regards,

Ralph

[MartinB]

Thanks Ralph. You need both a dew shield and a dew strap to control the dew. The combination of the 2 will nearly always do the trick although I've had to resort to an occasional blast with a hair dryer on the dampest nights

[dweller25]

Sounds like a happy ending.

Clear skies to you.

[red dwalf]

have not read all the threads but have you tried collminating it by eye ?

stand at the front of the scope about 2 meters away, look stright at it, looking into the scope, and have a look at the rings that are generated.

thet should all be visable and equal dimensions around the center circle, looks like rings on a pond when you drop a stone in, all the circles will be the same diameter from the center.

hope this makes sense

[red dwalf]

just read, you got it sorted, should read all the treads

[Virgoman]

Hi all,

No problem red dwalf and thanks dweller25. The scope arrived today, courtesy of Citylink. The package awaits.......... and the weather......sleet and awful.

Regards,

Ralph

[Virgoman]

Hi All,

Opened parcel last night and wow... front end is crystal clear. I have posted before and after photos and the difference is amazing.

Kind regards,

Ralph

[michael.h.f.wilkinson]

That's what a C8 should look like! There are some clear patches of sky over here, so I hope you get a look soon. Saturn is a stunner through a C8.

Cheers

Michael

[Virgoman]

Hi Michael,

Hope all is well.......yes chalk and cheese springs to mind!! Yes Saturn is beckoning...

all the best,

Ralph

[michael.h.f.wilkinson]

Had a really great look at Mars yesterday through my C8. Seeing was awesome, using my new Radian 8mm 250x was no problem. Mars may be getting smaller but on good nights shows a great deal of detail. Had serious problems with dew on the corrector plate later in the evening though, this ruined my chance of imaging Mars and seeing Saturn (bleh).

[Virgoman]

Hi Michael,

I`m hoping to get out later this week - ironically am waiting on anti dewing kit to arrive. Most nights here are hopeless as far as dew is concerned. High pressure is forecast for later this week hopefully clear skies with decent seing. It really is cracker when seeing is as good as you describe and reveals just what the scope is capable of resolving. I can`t wait - hopefully will have a few decent images to post on here soon.

Kind Regards,

Ralph