Decloaking BST Starguiders

[doublevodka]

So as I couldn't find a thread anywhere explaining the process here it is for future reference. We start here.

Then, unscrew the nosepiece as it has a flange that locks the body in place

Then raise the twist up eyecup as it make it easier to grip

Then you can unscrew the body of the eyepiece

Then reconnect the nosepiece and you are finished

You can also remove the rubber eyecup if you wish, just peel it upwards, I've left mine in place because I like it, and the cap fits to it.

Hopefully this is useful to someone 👍

[DaveL59]

wow you have to wonder what that extra bodywork adds to the price, does it actually add any functional benefit rather than just aesthetics?

[doublevodka]

13 minutes ago, DaveL59 said:

wow you have to wonder what that extra bodywork adds to the price, does it actually add any functional benefit rather than just aesthetics?

Just aesthetics as far as I can tell, many manufacturers do the same, I guess the extra weight makes it feel more "premium" to some people 🤷‍♂️

[Louis D]

I can unscrew the printed ring and then the colored beauty ring slips off, but the big upper part won't unscrew or slip either direction.

However, I was trying to get rid of the eye cup because it eats up 4mm of eye relief, causing the eyepiece to go from 16mm to 12m of ER, making it appear more like a Plossl with eyeglasses.  It appears the eye cup is still solidly attached when done with your decloaking.

Thanks for the clear photos and explanation, though.

[doublevodka]

2 hours ago, Louis D said:

I can unscrew the printed ring and then the colored beauty ring slips off, but the big upper part won't unscrew or slip either direction.

However, I was trying to get rid of the eye cup because it eats up 4mm of eye relief, causing the eyepiece to go from 16mm to 12m of ER, making it appear more like a Plossl with eyeglasses.  It appears the eye cup is still solidly attached when done with your decloaking.

Thanks for the clear photos and explanation, though.

Eyecup peels off upwards, hopefully these two shots help

As for the body, once you have the eyecup off and the top fully extended, the body unscrews the other way. Grip tight with both hands and twist in opposite directions worked for me. It was tight the first time but no threadlock as far as I can see

[Louis D]

4 minutes ago, doublevodka said:

Grip tight with both hands and twist in opposite directions worked for me. It was tight the first time but no threadlock as far as I can see

I guess I'll have to give it a bit more effort now that I know it should go downward.

I've pulled the rubber eye cup off before.  I'll have to try using a lens spanner/wrench to undo that top ring to see if the whole assembly drops off downward.

I'm trying to make these things eyeglass friendly for me and my daughter.  The both of us have a lot of eye astigmatism.  I much prefer the Meade HD-60 line for this reason.  There's basically no eye lens recession once you flip down the rubber eye cup and fully twist down the extendable eye guard.  She's got both sets at her house right now, so uncloaking experimentation will have to wait.

[doublevodka]

5 minutes ago, Louis D said:

I guess I'll have to give it a bit more effort now that I know it should go downward.

I've pulled the rubber eye cup off before.  I'll have to try using a lens spanner/wrench to undo that top ring to see if the whole assembly drops off downward.

I'm trying to make these things eyeglass friendly for me and my daughter.  The both of us have a lot of eye astigmatism.  I much prefer the Meade HD-60 line for this reason.  There's basically no eye lens recession once you flip down the rubber eye cup and fully twist down the extendable eye guard.  She's got both sets at her house right now, so uncloaking experimentation will have to wait.

I believe the top ring allows removal of the twist up piece, I seem to remember seeing that somewhere.

It'll make your wallet hurt a bit, but as you both have astigmatism it may be worth looking at this https://www.televue.com/engine/TV3b_page.asp?id=54

[Louis D]

7 minutes ago, doublevodka said:

I believe the top ring allows removal of the twist up piece, I seem to remember seeing that somewhere.

It'll make your wallet hurt a bit, but as you both have astigmatism it may be worth looking at this https://www.televue.com/engine/TV3b_page.asp?id=54

The problems with Dioptrx are

• It won't fit all eyepieces
• Still requires about 15mm of usable eye relief, so not a panacea for astigmatism sufferers
• Prevents view swapping unless you both have the same amount of astigmatism (you can simply adjust the angle by rotating it if it differs between observers)
• Requires one per eyepiece unless you like messing about in the dark swapping it across eyepieces
• Still leaves you blind when looking up to the sky from the eyepiece
• The correction angle changes depending on the altitude of the object when using a Dob requiring retuning between objects.

Using long eye relief eyepieces with eyeglasses pretty much eliminates these issues except that eyepiece choice becomes a bit more limited due to needing 17mm to 18mm of usable eye relief.

[doublevodka]

15 hours ago, Louis D said:

The problems with Dioptrx are

• It won't fit all eyepieces
• Still requires about 15mm of usable eye relief, so not a panacea for astigmatism sufferers
• Prevents view swapping unless you both have the same amount of astigmatism (you can simply adjust the angle by rotating it if it differs between observers)
• Requires one per eyepiece unless you like messing about in the dark swapping it across eyepieces
• Still leaves you blind when looking up to the sky from the eyepiece
• The correction angle changes depending on the altitude of the object when using a Dob requiring retuning between objects.

Using long eye relief eyepieces with eyeglasses pretty much eliminates these issues except that eyepiece choice becomes a bit more limited due to needing 17mm to 18mm of usable eye relief.

Fair play, you have definitely done your research there 👍 It certainly limits things a bit, using a barlow instead of shorter focal length eyepieces would help keep the costs down a little, or there's EEVA but I suspect like me you like to see things for yourself

[jjohnson3803]

Whoa.  Never would have guessed that the EPs have "filler" in them.  I'd try it on my 25mm, but I'm leery that I'll break the thing somehow.  Oh well, wish me luck!

 

[Louis D]

The Meade 5000 Plossl/SWA/UWA and Celestron Axiom LX/Luminos are all famous for having bulky outer coverings that can be removed to make them lighter by about 1/3rd and slimmer.

[DaveL59]

Hmmm, the perception of quality/luxury at the cost of resources, in the environmentally aware times we are now in I wonder if they'll revert to more eco friendly designs?

Tho I have to admit too that when I built or shopped for HiFi gear, proper solid knobs was always a points winner vs ally covered plastic ones, they just felt better 🙂 

[Franklin]

12 minutes ago, DaveL59 said:

I wonder if they'll revert to more eco friendly designs?

BCOs are no frills basic eyepieces with excellent glass.

[Zeta Reticulan]

I've always wondered about decloaking my 19mm Luminos. It's basically a paperweight at the moment.

[Louis D]

22 hours ago, Zeta Reticulan said:

I've always wondered about decloaking my 19mm Luminos. It's basically a paperweight at the moment.

Peel off or puncture the Celestron logo and you can then access the small screw that the eye guard rides up and down on.  Unscrew it all the way with a jeweler's screwdriver, lift off the outer carapace, clean off the grease left on the main eyepiece casing, and store the screw and carapace together in case you ever want to put it back on.  BTW, the lens cap won't fit anymore.

[Zeta Reticulan]

6 minutes ago, Louis D said:

Peel off or puncture the Celestron logo and you can then access the small screw that the eye guard rides up and down on.  Unscrew it all the way with a jeweler's screwdriver, lift off the outer carapace, clean off the grease left on the main eyepiece casing, and store the screw and carapace together in case you ever want to put it back on.  BTW, the lens cap won't fit anymore.

OK, thanks. I think I've seen pictures of the procedure. It would certainly help with the weight of the thing.

[Mr Spock]

Small and very light. No weight - no frills. Great optics too 

[Louis D]

9 hours ago, Mr Spock said:

Small and very light. No weight - no frills. Great optics too 

If only I didn't have such strong astigmatism in my observing eye.  I do have a Circle-T Edscorp 25mm which I can use with eyeglasses, but it's not very sharp outside the central area at f/6.  I suppose if I had a tracking mount it might be useful.  Are the shorter focal length Abbe orthos sharper across the field at f/6?

[Mr Spock]

I use these at f5 and they are sharp right to the edge. The 42-48 degree fov means tracking is essential. For planetary they are hard to beat. 

[Louis D]

I guess mine's defective.  I took it apart after noticing it wasn't all that great, cleaned it up, and tried all four orientations of the two lens groups, but even in the best orientation (the original), it's still not all that great.

Edited July 25, 2022 by Louis D

[Second Time Around]

On 20/07/2022 at 17:02, Louis D said:

The problems with Dioptrx are

• It won't fit all eyepieces
• Still requires about 15mm of usable eye relief, so not a panacea for astigmatism sufferers
• Prevents view swapping unless you both have the same amount of astigmatism (you can simply adjust the angle by rotating it if it differs between observers)
• Requires one per eyepiece unless you like messing about in the dark swapping it across eyepieces
• Still leaves you blind when looking up to the sky from the eyepiece
• The correction angle changes depending on the altitude of the object when using a Dob requiring retuning between objects.

Using long eye relief eyepieces with eyeglasses pretty much eliminates these issues except that eyepiece choice becomes a bit more limited due to needing 17mm to 18mm of usable eye relief.

On the rare occasions I share my scope with others I do use my glasses.  However, we're all different and I much prefer a Dioptrx over glasses for the following reasons. 

1) I wear my glasses on a cord and have no problems taking them on and off - it becomes automatic 

2) In any event, I have no presbyopia and so don't need glasses at all for looking at close range objects such as screens or maps

3) I have a Dioptrx on my finder eyepiece, but even without this I don't find astigmatism critical on a finder as it's doing just that - finding

4) The coatings are better than on even the top of the range Rodenstock lenses on my glasses

5) The angle of my astigmatism changes between my annual eye tests.  With a Dioptrx I can adjust this at the telescope 

6) I find that, like many, I need an extra 0.25 correction for astigmatism at night 

 

7) And most of all, having done head to head tests I found that I can see more with a Dioptrx than with my glasses

 

As I said, we're all different, and so there's no right or wrong.  I just wanted to put across a different point of view.