LF help on EP for the Celestron DX102AZ - BST StarGuider 60º and TS-Optics 60º - the same?

[Guest]

BST StarGuider 60º 8mm ED Eyepiece | First Light Optics

Teleskop-Express: TS-Optics 1.25" ED eyepiece 8 mm - 60° flat field, long eye relief

I've read that several of these brand have the same origin, often from China and then just adding different brand name to them. The shape, look and even color seem to be the same. Is the quality roughly the same?

And will it be a good fit for the Celestron Starsens explorer DX102AZ? Which sizes would be good to add for a beginner? (the inc. EP from DX102 prob won't be used as I've read bad things about them). Open for any other option as well, but prefeer them to be from telescope express.

If it makes a difference, I don't wear glasses.

 

EDIT:

What is the difference between the two above vs. this one Teleskop-Express: TS-Optics Ultra Wide Angle Eyepiece 20 mm 1,25" - 66° field of view , I'm thinking specifically for the top part, this one doesn't have adjustable part for eye relief, is that mainly for people using glasses? For non glass users, should I rather get non eye relief EP?

Edited July 7, 2022 by Millenium
added text

[Zermelo]

You're right, the range usually known as the Starguiders in the UK are offered under a number of names. I'd not seen the Teleskop-Express version, but they look identical, and they are a trusted supplier. That range of eyepieces is good value, they perform well and are often recommended here as a first upgrade.

The refractor you mention is F6.5, so that range of eyepieces will work well with it. You should notice an improvement  over the eyepieces supplied with the scope (you will probably want to replace the 10mm first). The other range that you link to is a different design, though I've seen a few versions of that one too.

Eye relief is the distance above the eyepiece that you need to position your eye to view the image. Some eyepieces like the TS-Optics ED have the adjustable cup which serves two purposes: it can help you to position the eye in the correct position (without "hovering") and it helps to cut out light from the surroundings that can affect the contrast of the view. That other 66 degree eyepiece has a soft rubber cup for the same purpose, but it is a fixed height (they can usually be folded down if necessary).

As to the sizes (focal lengths) to get, partly that will come down to how much you want to spend. There are several threads discussing this, but the best place to start would be: https://stargazerslounge.com/topic/43171-eyepieces-the-very-least-you-need/

Two other things to consider (i) a x2 "barlow" lens will double the range of focal lengths available from your collection and is very useful (ii) you might consider a zoom lens too, though a decent one will cost more than a fixed eyepiece (but gives you a whole range of focal lengths)

 

[Guest]

5 hours ago, Zermelo said:

You're right, the range usually known as the Starguiders in the UK are offered under a number of names. I'd not seen the Teleskop-Express version, but they look identical, and they are a trusted supplier. That range of eyepieces is good value, they perform well and are often recommended here as a first upgrade.

The refractor you mention is F6.5, so that range of eyepieces will work well with it. You should notice an improvement  over the eyepieces supplied with the scope (you will probably want to replace the 10mm first). The other range that you link to is a different design, though I've seen a few versions of that one too.

Eye relief is the distance above the eyepiece that you need to position your eye to view the image. Some eyepieces like the TS-Optics ED have the adjustable cup which serves two purposes: it can help you to position the eye in the correct position (without "hovering") and it helps to cut out light from the surroundings that can affect the contrast of the view. That other 66 degree eyepiece has a soft rubber cup for the same purpose, but it is a fixed height (they can usually be folded down if necessary).

As to the sizes (focal lengths) to get, partly that will come down to how much you want to spend. There are several threads discussing this, but the best place to start would be: https://stargazerslounge.com/topic/43171-eyepieces-the-very-least-you-need/

Two other things to consider (i) a x2 "barlow" lens will double the range of focal lengths available from your collection and is very useful (ii) you might consider a zoom lens too, though a decent one will cost more than a fixed eyepiece (but gives you a whole range of focal lengths)

 

Thank you so much for the lengthy and detailed answer, much appreciated! About the "hovering" mentioned, is this something most people would have to do to get correct focus, or is it mostly people with "incorrect eyesight"? (I just assume it's to get the correct focus, please correct me if wrong).

Which one of the two types would you recomend based on your experience and thoughts? (fixed height or adjustable?)

Thank you again for taking the time.

I also noticed a big range of different EP in your signature, which one do you personally feel has the best value/price quality ratio?

Edited July 7, 2022 by Millenium

[Zermelo]

1 minute ago, Millenium said:

Thank you so much for the lengthy and detailed answer, much appreciated! About the "hovering" mentioned, is this something most people would have to do to get correct focus, or is it mostly people with "incorrect eyesight"? (I just assume it's to get the correct focus, please correct me if wrong).

Which one of the two types would you recomend based on your experience and thoughts? (fixed height or adjustable?)

Thank you again for taking the time.

By "hovering" I just mean positioning your eye in the best position without touching the eyepiece. It doesn't affect the focus (you use the focuser for that), it's to do with the best position for the eye to see the image that the eyepiece produces. Different eyepiece designs have different distances (eye relief). Some eyepieces are more difficult to use in this respect than others (they can "black out" easily, and you struggle to see the whole image). I've never had any problems with the Starguiders, so I don't bother screwing up the eyecups. All this is true even if you don't wear eyeglasses, but if you do wear glasses then you need to choose eyepieces with greater relief to allow for the glasses between your eye and the eyepiece.

If I were you I would go for the ED eyepieces. not because of the adjustable eyecups, but because they are widely recommended as decent performers. I'm not saying that the others you mentioned wouldn't be good, but the Starguiders/etc are a very well known range and recommended often.

 

[Ricochet]

10 hours ago, Millenium said:

What is the difference between the two above vs. this one Teleskop-Express: TS-Optics Ultra Wide Angle Eyepiece 20 mm 1,25" - 66° field of view 

The difference is that the Starguider/TS ED is a good line of eyepieces whilst the 66° line are a waste of money. At F6.5 the longer Starguiders (18,25) won't be great near the edge of field but I am sure the 66° will be much worse. 

10 hours ago, Millenium said:

For non glass users, should I rather get non eye relief EP

No, buy the optically better eyepiece whatever the eye cup design. If you need to wear glasses you have to look at the eye relief but without glasses just buy the eyepiece that matches your needs. Despite the adjustable eyecup the Starguiders do not have enough eye relief for glasses. 

11 minutes ago, Millenium said:

About the "hovering" mentioned, is this something most people would have to do to get correct focus, or is it mostly people with "incorrect eyesight"? (I just assume it's to get the correct focus, please correct me if wrong).

It is how far your eye must be from the lens and the same for everyone. It has nothing to do with focus, which is how far the eyepiece must be from the objective. 

[Guest]

51 minutes ago, Ricochet said:

The difference is that the Starguider/TS ED is a good line of eyepieces whilst the 66° line are a waste of money. At F6.5 the longer Starguiders (18,25) won't be great near the edge of field but I am sure the 66° will be much worse. 

No, buy the optically better eyepiece whatever the eye cup design. If you need to wear glasses you have to look at the eye relief but without glasses just buy the eyepiece that matches your needs. Despite the adjustable eyecup the Starguiders do not have enough eye relief for glasses. 

It is how far your eye must be from the lens and the same for everyone. It has nothing to do with focus, which is how far the eyepiece must be from the objective. 

Perfect, thanks for confirming. I'm thinking about keeping the 10mm + 25mm and then perhaps buy a 18mm TS ED. I will probably replace the 10mm and perhaps the 25mm in time, but in the beginnig I just wanna see how big of a difference and start small and expand more as I go. Which of the barlow lenses would you recommend from this site: Teleskop-Express: Increase or decrease the magnification

I'm open to any suggestion, but perhaps a barlow that matches the same quality of the TS ED EP.

Thanks in advance!

[Zermelo]

Some numbers.

Your scope aperture is 102mm, and a rule of thumb suggests that you don't push the magnification beyond about x200 under the best conditions. But the design of that scope will give some colour fringing, which will be more noticeable with higher magnification, so perhaps something like 120x might be a more realistic maximum.

Your scope focal length is 660mm, so an 18mm eyepiece would give you around x37.  With a x2 barlow it would be x74. You might be better off going with the 15mm eyepiece, which would give you x44 and x88, along with your existing 25mm giving you x26 and x52. And perhaps later adding the 12mm, giving x55 and x110.

You don't have to spend very much on a Barlow to get something that will match those eyepieces in quality. I have this one, which I have used successfully with the Starguiders (but do note that the "extra" x1.3 magnification level that it mentions may or may not be achievable with the eyepiece, as some do not have enough room to accommodate the screw-in part). I don't recognize any of the others on the TS site, some of the cheaper ones may be as good. Perhaps some of our European members may be able to comment.

[Louis D]

I compared the BST Starguiders (AT Paradigms for the set I picked up) to the Meade 5000 HD-60s in the following thread some years back:

I preferred the HD-60s due to much better eyeglass friendliness and somewhat sharper views.  The 12mm and lower focal lengths in both lines are the standouts.  Unfortunately, the HD-60 line has been discontinued.  The Celestron X-Cel LX line is the closest in performance to them from what I've read that are still being sold new.

13 hours ago, Millenium said:

What is the difference between the two above vs. this one Teleskop-Express: TS-Optics Ultra Wide Angle Eyepiece 20 mm 1,25" - 66° field of view , I'm thinking specifically for the top part, this one doesn't have adjustable part for eye relief, is that mainly for people using glasses? For non glass users, should I rather get non eye relief EP?

I compared the SVBONY 68° Ultra Wide Angle 20mm, which is optically the same as the TS-Optics UWA 20mm, to other eyepieces in the 20mm range in the following thread:

You can look at the AFOV images to get an idea of how it performs at f/6.

It's fine in slow scopes (f12 and up) in my experience, but I wouldn't recommend it for your scope (f/6.5).  They're also terrific in binoviewers when used at f/18 in my experience.