Vintage(ish) vs. Modern(ish) 8" SCT

[badgerchap]

Today I added a second 8" Celestron SCT to my collection, from sometime in the 90s (thanks for the ID John). This joins my early-mid 2010s version. They're both the black tube, but the newer edition has Starbright XLT coatings as opposed to plain Starbright, and it is also Fastar compatible, although that shouldn't affect this comparison.

Also irrelevant to the comparison but very relevant to me is the mounting. The newer scope is sitting on an EQ5 with a wooden tripod, making it rather low to the ground. By contrast the older scope sits in its original fork mount on a wedge atop what appears to be a homemade tripod - if it's not homemade, suffice it to say that modern manufacturing has made some serious improvements. This aside this old setup is higher, not requiring me to bend down, although the height is fixed so others might not be so fortunate.

So how do the two scopes fare against each other? I am sharing eyepieces and the diagonal between the two scopes so that only the scope optics are compared.

Initially I have setup very quickly and not allowed any cooldown time. Firstly to the Moon, which looked marvellous in both scopes. If I really had to be picky, there is a very slight improvement in the newer optics. There was a very, very slight yellowish cast to the older image, but it was almost imperceptible and could even have been my expectation causing an illusion.

Next to Jupiter, which may even have been slightly nicer in the older scope. I was able to pick out both equatorial bands and the GRS in both scopes with the 40mm. Saturn also was brilliant at 40mm and 20mm too, with nothing to choose between the optics. The older scope may just be a little softer towards the edge of the field, but being standard, non-HD Celestron SCTs, neither are wonderful here, but for visual use I'm not really bothered.

If optics were the only consideration and I was really forced to choose, the XLT version would win by the narrowest of margins, but of course it's not just about optics. The ease of use and comfort of the older mount, the lack of counterweights, the ***battery powered!!!!!*** tracking, the natural eyepiece height and the very convenient handle put the older scope ahead in my eyes.

Now. Financially speaking I'm going to have to sell one of these (and some other gubbins) to get the frac I've been lusting over. But which one?! Better do some more observing after cooldown and maybe even a bit of imaging.

[badgerchap]

Further testing and I'm getting closer to a favourite. The older scope is really quite nice. The convenient controls and comfortable viewing are absolutely swinging it. Even if I could swap the newer scope onto the old mount (I don't think I can) I wouldn't. The 90s OTA gives lovely views, and tonight has shown me more detail on Jupiter than I've ever seen before. Got to 203x which gave some wonderful moments. It feels like it deserves its place on that old mount.

 

Well done 1990s Celestron!

[John]

On thing you need to watch out for with the older SCT's is mirror flop.

I had one about the age that yours is and it had that issue. Basically the mirror would move slightly as the scope was pointed at different angles which put the scope out of collimation.

Your older one might not have that issue though. Not all of them did.

 

[badgerchap]

7 hours ago, John said:

On thing you need to watch out for with the older SCT's is mirror flop.

I had one about the age that yours is and it had that issue. Basically the mirror would move slightly as the scope was pointed at different angles which put the scope out of collimation.

Your older one might not have that issue though. Not all of them did.

 

Yes, that's what I've read about. I've not noticed anything yet, but it's probably too early to tell. I'm primarily using it for visual use, so I'm not too concerned.

I understand the newer versions are less prone to it.