Can I stand an SCT on its front for storage?

[cshahar]

Hi All:

I haven't used an SCT in 25 years! A more experienced amateur who visited me suggested that I should not stand the RC I was using on its front. I was wondering if that is also a problem with my new 9.25 Edge? Sorry for such a basic question!

-Charles

[SkyBound]

I personally don't see a problem...but I may stand corrected on this

[kerrylewis]

I have read somewhere on the forum (I think) that it is not recommended  - something to do with the grease in the mirror end potentially running down (I think). However, it's not really convenient for me to store my 9.25 any other way so it's been stored like that for over 3 years and I've not experienced any problems. 

[ChrisLX200]

No particular reason other than the fact you would be better off not having an optical surface available for any dust/spots of lube to settle onto directly if you can possibly avoid it (and you can by simply keeping it horizontal), but other than that I don't think it will make any difference. My 10" has a full-length dovetail so it's easy to lay it horizontal. I can't think you would gain much space by storing it nose-down?

ChrisH

[SkyBound]

Yes, mine is stored nose down, it is still on its fork mount, but always put away with eyepiece facing up and corrector facing down. 

The grease should not run, it is too thick, and if it does run, then it will run when in use when pointing up and end up all in the back of the scope behind the main mirror, which would not be good... and it would mean someone has re greased with the wrong stuff ?

[Linda]

When I have it at home on an EQ mount, I never worry obout which way it stands, pointing upwards or downwards or horizontal. Outside I usually point it downwards so that birds can't make the schmidt plate dirty, while it is cooling down.

[cshahar]

Thanks everyone. I appreciate the advice!

-Charles

[baggywrinkle]

My 9.25 when not on the mount sits face down on a pad with a dust cover, not had any issues.

[Dave In Vermont]

I have often balanced my SCT's on their front-end for brief periods while I set up other gear before attaching them to their mounts, etc. But I wouldn't suggest storing them for any period of time this way. Or at all on very hot days (or nights). Here's why:

The focuser on these works by way of the primary-mirror being on what is called a 'sled' - in which it slides back & forth. This 'sled' has grease (of varying composition and quantity - depending on make & employee) on it. In hot weather, this grease can melt and possibly drip a bit. If it drips down and gets on your corrector.....Need I say more? You'd be an unhappy-camper if you needed to remove the corrector for cleaning and proper orienting to replace in the proper position.

The best way to store an SCT, MCT, ?CT, is with the OTA either level, or nose-up a bit.

Hope this helps,

Dave

[SkyBound]

1 hour ago, Dave In Vermont said:

I have often balanced my SCT's on their front-end for brief periods while I set up other gear before attaching them to their mounts, etc. But I wouldn't suggest storing them for any period of time this way. Or at all on very hot days (or nights). Here's why:

The focuser on these works by way of the primary-mirror being on what is called a 'sled' - in which it slides back & forth. This 'sled' has grease (of varying composition and quantity - depending on make & employee) on it. In hot weather, this grease can melt and possibly drip a bit. If it drips down and gets on your corrector.....Need I say more? You'd be an unhappy-camper if you needed to remove the corrector for cleaning and proper orienting to replace in the proper position.

The best way to store an SCT, MCT, ?CT, is with the OTA either level, or nose-up a bit.

Hope this helps,

Dave

If the grease ever melts or drips,  then someone has used the wrong grease, this should never happen, as I said before mine is stored on its fork mount in the down facing position, and all through the summer, even on hot days, and the grease has stayed well put

[ronin]

I suspect the problem will be one of gravity, as anything inside will drift/fall down to the corrector plate. Then one day you will notice this and want to clean it. That then starts off another area of contention.

Cannot say that in a non-down position nothing will get on the front corrector anyway but I would have thought that gravity would help stuff get there. Also it seems that many SCT's are stored in the front down position - is it right to presume this is a sort of park/storage position, it certainly means the unit is more compact.

[Dave In Vermont]

Well let's just take a look, shall we?

 

 

And.....

 

 

By the by, I'm also a bicycle-mechanic who has more than a passing relationship with grease - many types and ingredients, some excellent and some dreadful. From reports I've read from such expert sources on SCT's and other Cassegrains, from such notables as Doc Clay Sherrod and Rod Mollise, there is no single grease that has been used over the years by the employees at Meade and Celestron and other folks. And some employees, who apply grease to these scopes, use way too little, while others grease the Dicken's out of these scopes. In my experience as a 'wrench' on bicycles, who has taken apart many, many bicycles that were set-up by supposedly skilled mechanics, suffer from having 'way-to-little,' to the far more common 'way-to-much' phenomena. So using too much is Human-Nature. Also, when you take these machines apart, most lay-persons do not remove ALL the old grease before re-greasing the item. This often leads to a mixture of greases being used. And this encourages the hybrid-grease to change it's viscousity - meaning, usually, liquifying. Not good!

So in my opinion, and the opinions of Doc Clay & Rod Mollise, the best advice is to store a Cassegrain with the OTA either level, of 'snout-up' a bit.

Hope this helps to clarify,

Dave

[SkyBound]

27 minutes ago, Dave In Vermont said:

Well let's just take a look, shall we?

 

 

And.....

 

 

By the by, I'm also a bicycle-mechanic who has more than a passing relationship with grease - many types and ingredients, some excellent and some dreadful. From reports I've read from such expert sources on SCT's and other Cassegrains, from such notables as Doc Clay Sherrod and Rod Mollise, there is no single grease that has been used over the years by the employees at Meade and Celestron and other folks. And some employees, who apply grease to these scopes, use way too little, while others grease the Dicken's out of these scopes. In my experience as a 'wrench' on bicycles, who has taken apart many, many bicycles that were set-up by supposedly skilled mechanics, suffer from having 'way-to-little,' to the far more common 'way-to-much' phenomena. So using too much is Human-Nature. Alse, when you take these machines apart, most lay-persons do not remove ALL the old grease before re-greasing the item. This often leads to a mixture of greases being used. And this encourages the hybrid-grease to change it's viscousity - meaning, usually, liquifying. Not good!

So in my opinion, and the opinions of Doc Clay & Rod Mollise, the best advice is to store a Cassegrain with the OTA either level, of 'snout-up' a bit.

Hope this helps to clarify,

Dave

You really need to dust those scopes......that will stick to all that runny grease.

[Dave In Vermont]

Dust?  What 'Dust?' Maybe you should clean your glasses?

My storage is at a premium. My bike-shop does double-duty as a telescope-lab..... Or is that the other way around.....

By the by - if you ever clean off the old grease (talk to me about solvents and safe use first*, before blowing-up your house), and plan to apply new grease, I recommend "SuperLube." It contains a PTFE (Teflon®)-base. And such is applied in a very thin amount. Just enough to be visible on all surface-areas. And any excess removed with a clean cloth. I've seen that stuff still providing adequate lubrication in high-stress bearings on bicycles (such as the bottom-bracket where the pedals and crank-arms go through) for over 20 years after it was last serviced. I don't understand why it is, but most people seem to believe in a philosophy of: "If a little's good, then MORE must be better!"

Outer-Space is fascinating! People are bizarre!

Dave

 

* - I'm also an Organic-Chemist so I know about the safe handling of chemicals and their properties, toxicity, etc.

 

[cshahar]

I'm getting mixed messages here. To be safe, I'll store it for the winter level to the ground.

-Charles

[knobby]

To summarise...

In theory, you can store it how you like .

But after reading this thread how gutted are you (or any other readers) going to be if the grease does make its way down onto the corrector.

Mine is stored level, but I am paranoid 

[Davey-T]

Just to add more confusion I've had mine for many years mounted in the obsy and have no choice but to park it level however when I removed the corrector plate to drill out the original holes to fix a dovetail on "top" so they were bigger and metric I discovered that the corrector plate was held central by cork shims and these had obviously got compressed from being parked in the same orientation for years so the plate was slightly off centre, didn't seem to affect it visually but you never know if it would get worse the longer it's parked / stored in the same position.

Dave

[Dave In Vermont]

I can hear people pulling out clumps of their hair from their heads from all the way across the pond!

'Cork Shims' eh? I hope you put it back in exactly to the original orientation. But that's a very valuable addition to the existing knowledge-base about these 'beasts.' May I ask you, Dave, on what make and model was this you found these 'shims?'

Thank you!

Dave  @ 44.28N & 73.13°W

[Davey-T]

8 minutes ago, Dave In Vermont said:

I can hear people pulling out clumps of their hair from their heads from all the way across the pond!

'Cork Shims' eh? I hope you put it back in to exactly the original orientation. But that's a very valuable addition to the existing knowledge-base about these 'beasts.' May I ask tou, Dave, on what make and model was this you found these 'shims?'

Thank you!

Dave  @ 44.28N & 73.13°W

Meade 10" LX200R (before they had to change the name to ACF) trade descriptions or some such ?

I could actually lift the corrector plate up and down a bit when horizontal, got some more thin cork and re-centralised and yes I put it back in the same spot, it already had aligning marks on it.

Dave

[ChrisLX200]

My original 10" LX200 also has the shims..  Be very careful with the plastic retaining ring (that holds the corrector in place using a handfull of small screws), age makes them brittle and mine just disintegrated into about 4 parts upon removal.

ChrisH

[Davey-T]

9 minutes ago, ChrisLX200 said:

My original 10" LX200 also has the shims..  Be very careful with the plastic retaining ring (that holds the corrector in place using a handfull of small screws), age makes them brittle and mine just disintegrated into about 4 parts upon removal.

ChrisH

Sounds like another job for a 3D printer

Dave

[cshahar]

I finally decided to ask Celestron itself for a definitive answer to my initial query. Here is what they said:

Here are some points to keep in mind that may dictate your storage preference:

Orienting the tube vertically upwards puts the least long-term stress on the focusing mechanism from the mirror’s weight.
Racking the mirror all the way to the back of the tube (clockwise or near-focus) puts the least stress on the baffle-spindle that supports the mirror's weight.
If you have it vertically with corrector closer towards the ground then if it gets hot or humid then you can see grease from the focuser start to run and it could eventually drip down onto the corrector plate or secondary. I hope this helps.

Best Regards,
Christopher
Celestron Technical Support

[BritAngler]

Just turned my Mak pointing upwards and racked the mirror all the way back....