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Next eyepiece step


DavidJM

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Dilemna time......

I've realised that I'm not a fan of barlows, I'm also not loaded with cash. I love my two BST's 8mm and 25mm, I'm not so keen on my 15mm meade.

I've recently expanded my scope collection due to some inheritance with a 127 Mak, so my question is what would be a benefit to my eyepieces, replace the 15mm with a BST? Go lower than my 8mm? Go higher than 25mm? With BST's I would easily get two below £100 or go for something different and spend up to £100 on one eyepiece? Have a wide range of focal lengths and ratios over my three scopes, do I plan for different eyepieces per scope or stick to common eyepieces? Before anyone suggests Televues, I'll need to spend a fair bit on the wife before they turn up in the post? unless of course someone knows of deals going round

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22 minutes ago, Ruud said:

There are 4, 7 and 16 mm Nirvana eyepieces (82°) available that might fit the bill. I have a 16 mm and it is a really nice eyepiece. Better than anything you currently have, I guess.

see here: https://www.firstlightoptics.com/ovl-eyepieces/ovl-nirvana-es-uwa-82-ultrawide-eyepieces.html

 

 

 

16mm sounds good, would the 4mm be a stretch on magnification with my scopes?

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14 minutes ago, DavidJM said:

16mm sounds good, would the 4mm be a stretch on magnification with my scopes?

Not on the two Dobs as long as their figures are good.  However, I wouldn't typically go above 5mm on the 200P.  Never having had an f/4 scope, I can't advise there.  It comes down to a matter of how well corrected it is.  If it had a Zambuto level of correction primary, I'd say go for it for sure.  However, commercial grade fast primaries are rarely figured that finely, so very high powers may not be possible.  Besides, you've got plenty of other scope options for higher powers.

I would go for a widest field 2" eyepiece for the 200P Dob since you don't have anything below 25mm.  Something like the 35mm OVL Aero ED.  It works really well in my 8" Dob (with a GSO/Revelation coma corrector).

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4mm should be usable on f/8 and faster, but you also have to consider how much magnification the atmosphere allows.

I'll include my telescope and eyepiece spreadsheet. I prefer exit pupils between 1 and 5 mm, but on solar system targets I will go down to 0.5 mm. The atmosphere rarely allows magnifications over 250x here.

Especially when the telescope has a central obstruction, the exit pupil should not be larger than your own pupil (that's when the shadow of the secondary begins to fill your pupil, while at the same time the illuminated part of the exit pupil begins to get blocked by your iris).

ScopeCalculatorV2.xlsx

Stellariun has a nice oculars plugin. Try it. It'll help you estimate the sort of views you get from any prospective eyepiece.

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7 hours ago, Ruud said:

4mm should be usable on f/8 and faster, but you also have to consider how much magnification the atmosphere allows.

I'll include my telescope and eyepiece spreadsheet. I prefer exit pupils between 1 and 5 mm, but on solar system targets I will go down to 0.5 mm. The atmosphere rarely allows magnifications over 250x here.

Especially when the telescope has a central obstruction, the exit pupil should not be larger than your own pupil (that's when the shadow of the secondary begins to fill your pupil, while at the same time the illuminated part of the exit pupil begins to get blocked by your iris).

ScopeCalculatorV2.xlsx 254.22 kB · 4 downloads

Stellariun has a nice oculars plugin. Try it. It'll help you estimate the sort of views you get from any prospective eyepiece.

Thanks for the spreadsheet, hadn't thought of Stellarium

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The problem of having multiple scopes (a nice problem to have) is having the smallest number of EPs that are usable in all scopes. I figure you could use a higher power EP for good nights with the 8" Dob (5/6mm - ish)  but that may well be too much for the mak. The Nirvana has been mentioned and I'd second that, the 7mm I have is brilliant, and based on that a 16mm Nirvana would be a good replacement for your Meade.  If super wide isn't your thing then the Vixen SLVs are very good. Bottom line is that a couple of EPs would be good! 

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At some point I gave up having EPs that would be useful in ALL scopes in the house (from F/5 to F/10). My XW 5mm (and SLV 5mm) work fine in the APM 80mm F/6 or ST80, but only make occasional appearances in the C8 at F/10 (and then only for the moon). By contrast, the LVW 42 mm works fine in the C8 but only works in the APM 80mm F/6 if skies are particularly dark, due to the 7mm exit pupil. The Nagler 31T5 (a.k.a. Panzerfaust) is much better in the latter scope.

One thing to consider is the eye relief. The BSTs have decent eye relief, I believe the shorter Nirvanas don't. If you wear glasses their eye relief might be too tight.

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3 hours ago, michael.h.f.wilkinson said:

At some point I gave up having EPs that would be useful in ALL scopes in the house (from F/5 to F/10). My XW 5mm (and SLV 5mm) work fine in the APM 80mm F/6 or ST80, but only make occasional appearances in the C8 at F/10 (and then only for the moon). By contrast, the LVW 42 mm works fine in the C8 but only works in the APM 80mm F/6 if skies are particularly dark, due to the 7mm exit pupil. The Nagler 31T5 (a.k.a. Panzerfaust) is much better in the latter scope.

One thing to consider is the eye relief. The BSTs have decent eye relief, I believe the shorter Nirvanas don't. If you wear glasses their eye relief might be too tight.

I think that its inevitable that with 'scopes of differing focal lengths/apertures/ratios not all EPs will work with all scopes, and this is certainly so for me. However, I'm always mindful when contemplating buying an EP as to getting the best out of it in terms usage and with respect to this my comment "having the smallest number of EPs that are usable in all scopes" was probably badly worded! The 16mm Nirvana's eye relief is given as 12mm and I would agree that for use with specs' it  might be just a tad tight. I'm fortunate in that although I wear specs' I don't need them at the eyepiece and find the 7mm Nirvana nicely comfortable to use.

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1 hour ago, Alfian said:

I think that its inevitable that with 'scopes of differing focal lengths/apertures/ratios not all EPs will work with all scopes, and this is certainly so for me. However, I'm always mindful when contemplating buying an EP as to getting the best out of it in terms usage and with respect to this my comment "having the smallest number of EPs that are usable in all scopes" was probably badly worded! The 16mm Nirvana's eye relief is given as 12mm and I would agree that for use with specs' it  might be just a tad tight. I'm fortunate in that although I wear specs' I don't need them at the eyepiece and find the 7mm Nirvana nicely comfortable to use.

Hi Ian

I have specs for reading but don't use with scopes (at the moment), the Nirvana's certainly seem to be getting good responses, will likely go for the 16mm to replace the Meade, that will likely spur more purchase ideas knowing me 

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If there's nothing physically wrong with the Meade, I'd fill the gaps before replacing eye pieces and the it would be the 10mm SW that would go first!

You can't really have too many eyepieces at the shorter focal lengths as the small change in mm has a much bigger impact on magnification.

I don't know about the others, but a 6mm rather than a 4mm would be more use in the 8". :)

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1 hour ago, bingevader said:

If there's nothing physically wrong with the Meade, I'd fill the gaps before replacing eye pieces and the it would be the 10mm SW that would go first!

You can't really have too many eyepieces at the shorter focal lengths as the small change in mm has a much bigger impact on magnification.

I don't know about the others, but a 6mm rather than a 4mm would be more use in the 8". :)

Hi Ben, that's a really good point, I don't use the SW standard eyepieces I had with my scope, hadn't considered that a 10mm and an 8mm would give more options

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11 hours ago, michael.h.f.wilkinson said:

At some point I gave up having EPs that would be useful in ALL scopes in the house (from F/5 to F/10). My XW 5mm (and SLV 5mm) work fine in the APM 80mm F/6 or ST80, but only make occasional appearances in the C8 at F/10 (and then only for the moon). By contrast, the LVW 42 mm works fine in the C8 but only works in the APM 80mm F/6 if skies are particularly dark, due to the 7mm exit pupil. The Nagler 31T5 (a.k.a. Panzerfaust) is much better in the latter scope.

One thing to consider is the eye relief. The BSTs have decent eye relief, I believe the shorter Nirvanas don't. If you wear glasses their eye relief might be too tight.

Starting out, I would pick my eyepieces first of all for the scope I use for serious viewing, not the most used scope.  While it's true I have used my small 5 inch Dob more than the bigger 10 inch over the years , it has been totally worth it  to optimise my set around the bigger scope first of all. The smaller scope has mostly been a secondary consideration in my choice.  

It is often said that 3 magnifications for each scope will go a long way, something in the range of high, medium and low power, I think there is a lot of truth in that.

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There is a lot of good advice in the above posts. They do though demonstrate that an eyepiece to suit one user, does not necessarily suit another.

May I suggest a strategy to reduce risk?

Buy used eyepieces from SGL members. Look in the 'for sale' section.
Items there are generally in good condition, or like new. If not, the descriptions are generally honest.
An eyepiece in good order is going to be about 2/3 of new price.

Try out your almost new eyepiece(s).
If they work out well, keep them.
If they don't work out well, sell them on.

By doing this your cost is basically postage. The sale price from you is going to be similar to your purchase price - unless you have degraded the eyepiece.

When uncertain about any astro kit, I always try to buy used. Sometimes it can take a while to complete a sale on something that does not work out.

Hope this helps, David.

 

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7 hours ago, Carbon Brush said:

There is a lot of good advice in the above posts. They do though demonstrate that an eyepiece to suit one user, does not necessarily suit another.

May I suggest a strategy to reduce risk?

Buy used eyepieces from SGL members. Look in the 'for sale' section.
Items there are generally in good condition, or like new. If not, the descriptions are generally honest.
An eyepiece in good order is going to be about 2/3 of new price.

Try out your almost new eyepiece(s).
If they work out well, keep them.
If they don't work out well, sell them on.

By doing this your cost is basically postage. The sale price from you is going to be similar to your purchase price - unless you have degraded the eyepiece.

When uncertain about any astro kit, I always try to buy used. Sometimes it can take a while to complete a sale on something that does not work out.

Hope this helps, David.

 

Great advice, tbh I do tend to look at second hand, that's how I got my 200P, 2/3 price seems to be the recommendation, have to say I'm a bit of a squirrel and tend to struggle to let go of things☺

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On 23/03/2019 at 12:00, DavidJM said:

have to say I'm a bit of a squirrel and tend to struggle to let go of things

If you don't really need the money and have a place to store them properly, go ahead and be a pack rat.  I tend to only sell on large or very expensive things I no longer use.  Cars and furniture come to mind.  Houses can be rented out, so selling them on isn't always the right answer in a growth market.

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So rightly or wrongly I've ordered a couple more BST starguiders because the two I have have given so much pleasure, and have set my sights on getting a second hand televue plossl; I've only recently added my 127 Mak and have found the 25mm BST pretty good but still love my faster scopes and really want to test out with a tv, also 32mm tv plossl maybe useful with the Mak, just need to decide on focal length, more decisions?

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If you go for a Tele Vue 32mm plossl, budget for an eye guard extender as well:

https://www.firstlightoptics.com/tele-vue-eyepieces/tele-vue-twist-on-style-eyeguard-extender.html

Without the extender, you can find the eye relief of the 32mm TV plossl hard to hold. With the extender the eyepiece becomes really comfortable and easy to use.

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7 hours ago, John said:

If you go for a Tele Vue 32mm plossl, budget for an eye guard extender as well:

https://www.firstlightoptics.com/tele-vue-eyepieces/tele-vue-twist-on-style-eyeguard-extender.html

Without the extender, you can find the eye relief of the 32mm TV plossl hard to hold. With the extender the eyepiece becomes really comfortable and easy to use.

Thanks John, I'm learning ever day ☺

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Also, be aware that the BST Starguiders are pretty good eyepieces and compare well with TV plossls so don't expect startling differences. Subtle, maybe. :smiley:

I've owned many TV plossls and quite a few BST Starguiders so have been able to compare them a fair bit. The Starguiders are actually easier to observe with in some ways.

Nothing like finding out for yourself though :smiley:

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14 hours ago, John said:

If you go for a Tele Vue 32mm plossl, budget for an eye guard extender as well:

https://www.firstlightoptics.com/tele-vue-eyepieces/tele-vue-twist-on-style-eyeguard-extender.html

Without the extender, you can find the eye relief of the 32mm TV plossl hard to hold. With the extender the eyepiece becomes really comfortable and easy to use.

What's the usable eye relief on the TV 32mm Plossl?  Design ER is 22mm, and there appears to be a bit of recession to the eye lens, so is it closer to 20mm?  My 32mm GSO Plossl has only 15mm of usable eye relief due to eye lens recession, so it's a bit tight with eyeglasses.

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