frustration with Celestron x-cel. Any tips?

[Jimtheslim]

Having just bought a 10" f/4.7 reflector I thought I would treat myself to a new 8mm eyepiece, something I have been after for a while. I've always had Meade plossls before and they seem to work pretty well. The highest mag I have is 187x with the 6.4mm. So I decided to try something a bit more exotic in a magnification that is a bit more forgiving. Got it for a decent used price.

Just put it in the eyepiece holder and had a look at twilight Jupiter, on first sight I thought the seeing wasn't great but the eyepiece had potential. Unfortunately whenever I look around the eyepiece or the angle of my eye isn't absolutely straight on the whole eyepiece starts going black, a bit like the kidney bean effect I sometimes used to get with my 32mm plossl when used in my refractor. It is mighty annoying, just as you think your eye is relaxing on the target and starting to see a bit of detail, the whole things blacks out. 

Is this indicative of eyepieces like these? Is this a compromise for keeping a decent exit pupil? I will of course persevere, but I can see myself getting shot of it very soon unless there is a trick to using them properly and going back to plossls.

Any ideas/tips?

[Stu]

Does it have a twist up eye cup/guard Jim? That can help a lot with eye positioning

[michael.h.f.wilkinson]

Some EPs (even the Tele-Vue Delos) take some getting used to, others are more forgiving (like the Pentax XW). Very often setting the eye cup right makes a huge difference

[VilleM]

I had 12mm X-Cel LX. It was good but if your eye is too close the effect you described appears. This was one of the reason why I sold it and bought Baader Morpheus 4,5mm to replace it. If I can remember correctly there is a twist-up cup in X-Cel eyepieces.

-V

[Jimtheslim]

6 minutes ago, Stu said:

Does it have a twist up eye cup/guard Jim? That can help a lot with eye positioning

No, the eyecup is static, like a plossl. I'm thinking it might be an older discontinued model as I can't find the X-cel anywhere new in an 8mm and the barrels look different

[Jimtheslim]

1 minute ago, VilleM said:

I had 12mm X-Cel LX. It was good but if your eye is too close the effect you described appears. This was one of the reason why I sold it and bought Baader Morpheus 4,5mm to replace it. If I can remember correctly there is a twist-up cup in X-Cel eyepieces.

-V

the further my eye from the eyecup, the more the border appears round the edges.

[John]

I needed the eyecup on the X-Cell LX's I've used fully in the "up" position to avoid blackouts. The "down" position on these things is usually for those who wear spectacles when observing.

Sounds like you might have the older X-Cel (non-LX) version which did have a static eyecup.

The seeing conditions have not been great lately so it's probably best not to expect miracles from any eyepiece much above 150x even when you do find a good eye position.

 

[Jimtheslim]

150 was realistically the highest mag I wanted to go to. Just wondered what causes these blackouts, it's as if you looks lightly away from right dead centre and all you see is the inside of the eyepiece barrel. I will keep trying, but if the target is out of the very centre by just a few degrees it starts blacking out when you try and look at it

[Highburymark]

As John says it sounds as if you have the older, discontinued X-cel, which has eye relief of 20mm - which is large for this type of eyepiece, especially with a relatively modest 55 degrees field (AFOV). That means you have to position your eye - or hover is probably a better way to describe it - out from the eye guard. It can take a bit of practice. The newer LX range avoids the problem by having a twist up guard and 16mm of eye relief.

[Dave In Vermont]

There were Celestron X-Cel EP's - which were replaced by the X-Cel LX EP's. I don't know about the 8mm ones, but the 5mm X-Cel was called "The worst eyepiece of all time" in a CN review. I remember this clearly as, guess what? Yes - I have one!

Dave

[ronin]

Sounds as if you have the older X-Cel and not the newer X-Cel LX. Check the barrel it should clearly say C-Cel LX on it as in this extract from FLO:

https://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-lx-eyepiece.html

FLO says the LX's have twist up eyecups, as you appear to have none then I guess it is the older X-Cel, which never had a good reputation. If you bought it as an LX from a retailer then I would contact them, it may be an error or someone getting rid of olsd stock. Along similar I notice that we in the UK are still getting ES eyepieces that are Nitrogen purged whereas the US have had the newer Argon purged items for over a year. No difference optically but still the older variant.

If it is an LX version all I can suggest is that you have an eyepiece and a scope that simply do not get on together and possibly the eyepiece and your eyes are the same. This happens at times, there is no guatantee that the combination will actually work or is comfortable to you.

[Jimtheslim]

56 minutes ago, ronin said:

Sounds as if you have the older X-Cel and not the newer X-Cel LX. Check the barrel it should clearly say C-Cel LX on it as in this extract from FLO:

https://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-lx-eyepiece.html

FLO says the LX's have twist up eyecups, as you appear to have none then I guess it is the older X-Cel, which never had a good reputation. If you bought it as an LX from a retailer then I would contact them, it may be an error or someone getting rid of olsd stock. Along similar I notice that we in the UK are still getting ES eyepieces that are Nitrogen purged whereas the US have had the newer Argon purged items for over a year. No difference optically but still the older variant.

If it is an LX version all I can suggest is that you have an eyepiece and a scope that simply do not get on together and possibly the eyepiece and your eyes are the same. This happens at times, there is no guatantee that the combination will actually work or is comfortable to you.

It says x-cel on the side, but is definitely an older version I think. I'll just keep trying, maybe it just doesn't get on well with me/my scope. If this is the case I will sell it. I bought it used for a decent price so won't loose out by much I wouldn't imagine. Might give it a try in the refractor to see if I get the same issue

[Jimtheslim]

It was this one that I bought from the buy/sell forum

[Dave In Vermont]

That's the older version alright. My 5mm is about identical. The eye-guard is a dead give-away.

Dave

[Jimtheslim]

Thought it would be the older one. I jumped in and bought it because 8mm gives me 150x which is the magic number I have been after for viewing Jupiter. I'll persevere but if I have no luck and it's the same in my refractor I will look into either the newer version in the 9mm or an 8mm BST or even a Baader ortho. I'm just hoping that buying this f/4.7 scope isn't going to be a nightmare for finding eyepieces. My Meade plossls have no issues, but I wanted to spend a little more to get the most out of the scope. 

[Stu]

20 minutes ago, Jimtheslim said:

Thought it would be the older one. I jumped in and bought it because 8mm gives me 150x which is the magic number I have been after for viewing Jupiter. I'll persevere but if I have no luck and it's the same in my refractor I will look into either the newer version in the 9mm or an 8mm BST or even a Baader ortho. I'm just hoping that buying this f/4.7 scope isn't going to be a nightmare for finding eyepieces. My Meade plossls have no issues, but I wanted to spend a little more to get the most out of the scope. 

How about a bit of DIY? A little home made eyeguard made from a piece of foam which you can slide up and down??? Never tried it, just thought it might allow you to use the ep to see how the 8mm performs?

[Jimtheslim]

17 minutes ago, Stu said:

How about a bit of DIY? A little home made eyeguard made from a piece of foam which you can slide up and down??? Never tried it, just thought it might allow you to use the ep to see how the 8mm performs?

I like having a go at things like this. What kind of thing were you thinking? Maybe a roll of foam or rubber that can be tied to the outside of the barrel with an elastic band? I've tried it in the refractor, albeit in daylight but the problem persists. I can get a decent view if I hover over very near the eye cup so maybe extending it with a DIY job might be the ticket

 

[Stu]

Hi Jim, yes that's exactly what I was thinking. Just something to keep your eye positioned correctly.

[rockystar]

I had an eyepiece with exactly the same problem, so it never got used - it was a shame, because the view was magnificent when I was in the right place, it was just tricky to stay there. Fortunately i managed to sell it on without too much loss. it was only as I was packing it up to post it that I noticed the twist up eye guards. doh!

[bingevader]

Bicycle tyre inner tube?

The right diameter would slide or stretch over the end of the EP.

Roll it down to the correct height.

[Jimtheslim]

Well, here is my solution (hopefully). I found some black tennis racket handle tape in the garage and wound it round a couple of times. Marked where I needed to cut it and then carefully glued it fast [patent pending]. This was the third attempt. First with just one layer which didn't quite match the thickness of the existing eye cup. Second was a little too tight. It's actually pretty hard to get it so it's loose enough to slip on and up and down and tight enough to grip in place when you plonk your eye on it. I hope it works!

[bingevader]

That's the job!

[laudropb]

That should definitely help.

[michael.h.f.wilkinson]

19 hours ago, Dave In Vermont said:

There were Celestron X-Cel EP's - which were replaced by the X-Cel LX EP's. I don't know about the 8mm ones, but the 5mm X-Cel was called "The worst eyepiece of all time" in a CN review. I remember this clearly as, guess what? Yes - I have one!

Dave

The CN review was WRONG!

The 5mm X-Cel cannot possibly be as bad as the plastic H-9 (plastic "Huygens" that would probably have old Christiaan spinning in his grave) I once got with a scope. It isn't even heavy enough as a paperweight. Claustrophobic FOV, tiny eye relief, and even the on-axis performance was dreadful due to all the ghosting and flares. It was essentially impossible to focus with it. I removed the 1.25" barrel, blackened it properly internally, and inserted a Kelner 28mm from an old, broken Russian pair of 7x50 bins in it. That still acts as my kids' widest EP. The SR-4 I once had the profound lack of pleasure looking through must have been worse than the X-Cel. Non-existent eye relief tunnel-vision type AFOV, coatings quite horrible, so lots of internal reflections, even with just two elements in two groups.

[Dave In Vermont]

Did these ever make it onto the marketplace, Michael? That might be the criteria for having made it into a CN-review. Poor schleps shelling out money for the privilage of having their vision assaulted.

If you know of these being sold as is - please let me know. I should like to round out my collection!

Dave