SCT lifespan

[Allan3026 (Allan)]

Hi All
I'm considering buying an older SCT, and was wondering what the lifespan is for these scopes. In particular, do the mirrors degrade substantially over the years? Should I stick to under a certain age?

I've had Dobs in the past , 1 of which degraded badly and ended up in the rubbish. SCT,s being somewhat sealed should last a fair while longer I imagine.

[MortonH]

Hi Allan,

I recently bought an older black tube C8 with Starbright coatings that I believe is from '80s. There is no degradation evident in the optics and it performs well.

Of course the older optical coatings are less efficient. I think Celestron's Starbright XLT coatings transmit around 10% more light than the original Starbright.

[Dave882 (David)]

The c14 I use for most of my imaging and visual astronomy is a 90s black tube and there’s no noticeable degradation. However I will say there are some advantages of new versions:
- slightly more efficient coatings
- better focus mechanisms and less mirror shift
- fastar compatibility to attach a Hyperstar
- less chance it’s sustained damage during cleaning or general use

But I don’t think any of these are deal-breakers. A good sct will stay a good sct for a long time if it’s been well cared for.

[ChrisD (Chris)]

Originally Posted by Dave882

But I don’t think any of these are deal-breakers. A good sct will stay a good sct for a long time if it’s been well cared for.

Dave882 is absolutely correct.

I purchased a C8 in 1986, one of the very early Starbright scopes. It was a US$300 optional extra back then. I've always taken care to kept the scope dry when stored. I had the main mirror out just recently and it still looks pristine.

Chris

[Allan3026 (Allan)]

Thanks for the re assurance. Good to know they last. Now just need to decide between C9.25 and Meade 10".
I do like the Hyperstar option, so leaning towards C9.25.

[MortonH]

Originally Posted by Allan3026

Thanks for the re assurance. Good to know they last. Now just need to decide between C9.25 and Meade 10".
I do like the Hyperstar option, so leaning towards C9.25.

Might want to check the weights. Meade SCT's tend to be heavier than Celestron SCT's of the same aperture.

[Allan3026 (Allan)]

Originally Posted by MortonH

Might want to check the weights. Meade SCT's tend to be heavier than Celestron SCT's of the same aperture.

Thanks, good to know. I have an AZ EQ5 that will be used for visual. My plan was an older (Cheaper??) SCT to put side by side with my 4" APO for EAA

Older C9.25 means no Hyperstar.
Older Meade 10 sounds too heavy for my AZ EQ5.

Probably for another post, but is Hyperstar good for fast images with EAA?

[MortonH]

Originally Posted by Allan3026

Thanks, good to know. I have an AZ EQ5 that will be used for visual. My plan was an older (Cheaper??) SCT to put side by side with my 4" APO for EAA

Older C9.25 means no Hyperstar.
Older Meade 10 sounds too heavy for my AZ EQ5.

Probably for another post, but is Hyperstar good for fast images with EAA?

Eek! I'm visual only so no idea!

[By.Jove (Jove)]

Originally Posted by Allan3026

Probably for another post, but is Hyperstar good for fast images with EAA?

I don't see any reason why not... at that focal ratio you won't want exposures over 30 secs anyway, and if you're using SharpCap on a laptop or ASIAir to drive the rig, use Live Stacking should be fine.