Eyepiece Deleema v.2

[Kronos831]

Hey kronos here, i finally decided im  buying an 8 inch dobsonian telescope! i am currently figuring out the eyepieces i will be buying ,since ive heard the 10 mm isnt such of great quality and the 20mm is decent, i am considering bst star guider eyepieces thanks to some advice, i have been wondering tho, which size? I m going to be doing planetary observations and mostly dso .The telescope has a fl of 1200mm and i can buy up to 2 eyepieces, i am considering the 12 mm as i can compliment it with a barlow lens and achieve  200x magnification ! i ve heard thats as clear as it gets as of magnification/sharpness ,can it go over that? Also should i get a bigger fl mm eyepiece like a 32 for bigger objects if so are there a lot of big objects i need to buy the eyepiece for? And should i buy an eyepiece for tracking or just use the finderscope that will come with the skywatcher dob?( i dont have any expirience with finderscopes since i  have a celestron firstscope without the upgrade kit and just track my objects with the 20mm eyepiece provided so sorry if i am  lacking general and basic knowledge.

Thanks

Clear Skies

Kronos

[domstar]

Hi I would just get the scope and enjoy the views. You can upgrade at leisure but the two eyepieces should keep you going for a bit, and then you'll know more about what you need.

[SW130p]

Hi I have a 200pds 8" Scope and use the 8mm BST for planets. Its my go to eyepiece and on good nights I get good views with Jupiter. I also have the BST 5mm but don't get used often.  So in my option 8mm is good one to get.

[Greg6498]

1 hour ago, Kronos831 said:

Hey kronos here, i finally decided im  buying an 8 inch dobsonian telescope! i am currently figuring out the eyepieces i will be buying ,since ive heard the 10 mm isnt such of great quality and the 20mm is decent, i am considering bst star guider eyepieces thanks to some advice, i have been wondering tho, which size? I m going to be doing planetary observations and mostly dso .The telescope has a fl of 1200mm and i can buy up to 2 eyepieces, i am considering the 12 mm as i can compliment it with a barlow lens and achieve  200x magnification ! i ve heard thats as clear as it gets as of magnification/sharpness ,can it go over that? Also should i get a bigger fl mm eyepiece like a 32 for bigger objects if so are there a lot of big objects i need to buy the eyepiece for? And should i buy an eyepiece for tracking or just use the finderscope that will come with the skywatcher dob?( i dont have any expirience with finderscopes since i  have a celestron firstscope without the upgrade kit and just track my objects with the 20mm eyepiece provided so sorry if i am  lacking general and basic knowledge.

Thanks

Clear Skies

Kronos

Hello Kronos!

I, too, have an 8” Skywatcher Dobsonian! I use Explore Scientific and Baader Morpheus wide angle eye pieces listed below in my signature. I use the 18 mm the most and find that the three listed give me a wide range of options. I have used the wide angle versions as they are great for folks wearing glasses, offering great eye relief. I also upgraded my finder scope to the Explore Scientific 8x50 illuminated scope. HUGE DIFFERENCE!  Hope this helps!

[vlaiv]

I got 25mm and 10mm with my 8" dob when I bought it.

10mm saw little to no use, I think I gave it away (I included those two eyepieces with one of scopes I sold as extras)

For quite some time my main "finder / widefield" eyepiece was 32mm plossl. Next to that one I used 17mm, 12mm and 7 and 6mm for planetary, with various barlows.

32mm, 17mm, 12mm were GSO plossls. 7mm was HR Planetary type and 6mm Baader Classical Ortho.

Current EP lineup for dob is:

ES68 28mm for wide field (replaced 32mm GSO with a bit more FOV and darker background sky)

ES58 16mm - Main DSO work

ES82 11mm - high power DSO work and planetary (barlowed with x2.7 APM barlow)

Good options for focal lengths would be:

One long focal length for general low power observing / wide field. 32mm Plossl type or alike is good choice for this.

For general DSO work you would probably like something in 15-17mm range, but it depends on your sky conditions. You want exit pupil to be around 3mm or a bit less. Actually in strong LP I've seen recommendations to go between 3-4mm and in dark skies between 2-3mm (or was it other way around?  - I can't remember now) - so your safe bet is around 3mm and that is 18mm focal length (or a bit less).

12mm is nice focal length to have for high power DSO but also planetary when barlowed.

8" dob can do higher powers than atmosphere will allow on most nights. I pushed mine to x500+ but it was more to try it out than anything really usable. Up to x400 is ok, but you will not have steady skies for that sort of magnifications. Now days I stay in x200-x300 range (11mm with x2.7 barlow - that can operate at lower magnification if I don't put extender on it).

For very high magnifications you will want sharp eyepiece, so your plan to go to max x200 for now is good one.

 

[Ags]

I use the Super 25 as a finder with an ST80, as a finder eyepiece, and it does OK at the task. An ST80 is quite a challenge for eyepieces being an F5 (fast) and short focal length (field curvature). I am going to replace it sometime this year with a Nirvana ES 16  mm 82 degree, the reason being that light pollution is less troublesome at higher magnification. The Super 25 gives a very bright sky background leaving DSOs very faint and hard to spot.

[Ricochet]

I started with 8mm and 12mm Starguiders with my 8" dob, and was very pleased with them. At longer focal lengths I prefer the Explore Scientific 68° series (also sold as Maxvision and Meade SWA with a different eyecup design). The 24mm 68° (same FoV as a 32mm Plossl) wasn't quite wide enough in my opinion so I agree with @vlaiv that the 28mm is the better option. I now use a 28mm (82°) Nirvana but this may be harder to find.

[JOC]

I have the same truss tube Dob shown in the picture above.  FWIW 8mm is a size that I find I can use on all occasions I get the scope out - I too have the 8mm BST.  I've got higher magnification (a rather nice 5mm Pentax XW) and yes the scope will go to 5mm under UK skies, BUT it needs to be first class seeing and conditions.  I did once try 4mm, but I wasn't successful and sold it.  So based on that experience I find that 5mm is the absolute tops and 8mm the size you will probably go to the most.  If you want to see the moon I find that a 10mm works well.  FWIW I struck lucky with the 10mm and 20mm that came with my scope, both are quite OK EP's and even with a complete suite of much more decent stuff now they still get used, esp. if I want to go back to basics with things that I know work if I'm trying to find something or I'm having problems, don't ditch them without trying them they might well surprise you.

For finders I very soon ditched the straight through optical finder for a RACI one, but I was still having issues finding things that I could see in the sky with my eyes yet couldn't get the scope on.  So I bought a cheap 3D printed adapter from ebay and a cheap RACI second hand and did this:

With this combo slotted into the SW finder shoe I can find anything I can see in about 30 seconds flat.  The RACI I key absolutely into the telescope view and if the RDF is 'thereabouts' then I know what I can see with the RDF I can centralise in the RACI and then the scope will be on it.  TBH I think I would make sure you are happy with your finder/s before investing in EP's - all the EP's in the world are useless if you can't find things and that was my big issue with my Dob to begin with.

[Kronos831]

Thanks guys! I have settled on a 25 mm a 18 mm starguider with a 2 and 3x barlow so that gives me:25 12.5 6.25 18 9 and 4.5 mm . What do you guys think?

Also how will the Skywatcher s finder perform against other finders? Also should i get an adapter and get both rdf and the normal finder scope?

[JOC]

1 minute ago, Kronos831 said:

Also should i get an adapter and get both rdf and the normal finder scope?

Well you know my answer - see above.  It can't be beaten as a combo IMO.

[Ricochet]

40 minutes ago, Kronos831 said:

Thanks guys! I have settled on a 25 mm a 18 mm starguider with a 2 and 3x barlow so that gives me:25 12.5 6.25 18 9 and 4.5 mm . What do you guys think?

 

25mm + 3X barlow = 8.3mm

18mm + 3X barlow = 6mm

In any case, the 25 and 18mm Starguiders are unsuitable for an f6 scope in my opinion. The shorter ones are fine, but not those two. 

[vlaiv]

38 minutes ago, Kronos831 said:

Thanks guys! I have settled on a 25 mm a 18 mm starguider with a 2 and 3x barlow so that gives me:25 12.5 6.25 18 9 and 4.5 mm . What do you guys think?

Also how will the Skywatcher s finder perform against other finders? Also should i get an adapter and get both rdf and the normal finder scope?

I'm not sure about combination - someone who actually has these eyepieces and tried them with barlow will probably give more definitive answer, but here is my concern:

BST's already have plenty of eye relief at 16mm. Adding barlow lens will cause them to increase eye relief even further. If it stays below or at about 20mm it will probably be fine, but if it's increased further - it might make observing difficult. It's hard to keep pupil centered at very long eye relief and you will not be able to see complete field from that far away. Some longer focal wide field eyepieces start to vignette when used with barlow - so that is also something that needs checking out.

BTW, FLO is offering discount of 20% if you purchase 4 or more items in BST range (eyepieces and barlows), maybe three eyepieces and one barlow (x2) would be better option to consider?

 

[Kronos831]

Thanks guys for the good advice.Soo which ones should i get in your opinion?  Should i consider othet eyepieces for around the same price? Ughhh this is confusing xD

[JOC]

I'd be tempted to get a 8mm, 15mm and 25mm BST and not bother with a Barlow.  I must admit I have only got a 8mm BST for comparison, but it is a good EP from a range well recommended on SGL  You can see the whole range on this page, which I'm only linking to as it has pic of them of together rather than as a recommended seller https://www.365astronomy.com/BST-Explorer-Starguider-ED-Eyepiece-KIT-3.2mm-5mm-8mm-12mm-15mm-18mm-and-25mm-Eyepieces.html

[Kronos831]

Okay but what about planetary viewing? I m thinking that the 150 x magnification will be too little... I was thinking of a6mm but ill take a look at the 12mm

[Kronos831]

2 hours ago, Ricochet said:

 

In any case, the 25 and 18mm Starguiders are unsuitable for an f6 scope in my opinion. The shorter ones are fine, but not those two. 

So which ones should i get? Around the same price range speaking?

[Kronos831]

2 hours ago, vlaiv said:

 

 

BTW, FLO is offering discount of 20% if you purchase 4 or more items in BST range (eyepieces and barlows), maybe three eyepieces and one barlow (x2) would be better option to consider?

 

Something isnt right... I have 4 bst starguider s in the basket but i dont have a 20%  discount on all of them

[vlaiv]

My bad!

For some reason I read wrongly what has been advertised on FLO website, but here it is:

It looks like you get 15% off for 4 or more and 20% for 7 or more

[Ricochet]

3 hours ago, Kronos831 said:

So which ones should i get? Around the same price range speaking?

You will probably have to spend more. There is an 18mm Baader Classic Ortho if you don't mind the 50° field, a 16mm Nirvana-ES or something from the Explore Scientific 68° range. You can also look at the Ultra flat eyepieces, it depends which suppliers you can use. 

[Kronos831]

Oh thanks, my supplier s are flo what do you think about theze

[Ricochet]

They are a very similar design, I believe their 18 and 25 also have issues in faster scopes. I used to have a 7mm and preferred it a bit to my 8mm Starguider but the rest of the range may not be better than the equivalent Starguiders. 

[Kronos831]

Thanks so i ll get the 6mm bst one.Now based on flo s eyepieces which are good for arouns the same price (for dsos)

[vlaiv]

Are you certain that you are going to get 10 and 20mm with your Dob?

Which one did you order?

SW 8" Dob comes with 10 and 25mm eyepieces. 25mm is very decent eyepiece and you can use it for now for low power eyepiece. At some point you can think of adding 32mm plossl for wider views and as finder eyepiece.

For around 18mm have a look at this one:

https://www.firstlightoptics.com/ovl-eyepieces/skywatcher-extraflat-125-eyepieces.html

(19mm is probably best option)

A bit more expensive than Starguider, but supposed to be good.

But if you get 20mm eyepiece with your dob - use that instead - very small change from 18mm and 19mm to 20mm. In this case add 32mm as wide field / finder eyepiece and just keep using 20mm as DSO eyepiece (but compare it to 32mm and see if it's good or needs to be replaced).

10mm that you get, might also be decent eyepiece, so don't discard it yet.  Do get shorter FL eyepiece for planetary views, something like 6-7mm. This way you will know if your 10mm is good enough or you need replacement in this range (10-12mm).

What I'm trying to say is: you don't need to rush into buying whole set of eyepieces until you had a chance to learn to observe and to see what sort of preference do you have in eyepieces.

 

[Kronos831]

Thanks,but yep i do.... Brittan is leaving in march 26 and I'm going go have enough money in march 18 so unless i have very clear skies the first day,i wont be able to get more on time.Greece has strict laws about shipping From other countries outside the eu,and my primary supplier flo with the good prices,will be gone.I also will be getting the 25mm and 10mm one .i know i asked this question before but,will i be able to barlow the specific 25mm? Thanks

[JOC]

I can't see any reason why not.  It will come with a standard width and should slot straight in.  FWIW I have a x2 Barlow and rarely use it for EPs.  Mine is the so called Delux SW one and it is far more useful unscrewed into bits for attaching my DSLR to the focus unit with a T ring on the camera