Eyepieces.. :(

[AweSIM]

hi.. ive read quite a lot on eyepieces on this forum and it has helped me a lot.. but i still am a bit confused regarding a few things.. a true effect of the fact that theory is easy.. reality is a whole different story..

1. why are telescopes made to work with 1.25" and 2" EPs? i mean why not a standard? either 1.25" or 2"..

2. i am planning to buy a Skywatcher Explorer 200PDS.. the specs are confusing me.. it says it has a 2" crayford focuser with 1:10 dual speed transmission (ideal for astrophotography).. what is that supposed to mean? .. and does that mean that the scope accepts 2" EPs? it also says that a 1.25" reducer is included.. why 1.25"? does it mean that the scope can take 2" and 1.25" EPs? the stock EP is 28mm but doesnt mention the barrel size.. thats why im confused.. i was looking to buy some 1.25" EPs but now im confused.. as to whether i should be looking for 2" EPs or 1.25" EPs..

3. i checked the prices of some 1.25" and 2" EPs.. and ive deduced that 2" EPs are a LOT more expensive than 1.25" ones.. why is this so?

4. the description says that the 2" focuser can hold cameras of up to 2kg solidly.. does it mean that i wont be needing any T-Rings, etc? or do i still need them?

5. when youre using this scope for astrophotography.. you do remove the EPs right? if im wrong could someone please clarify this to me?

6. its been advised that the scope EPs are usually cheap and you should buy new ones in low, medium and high magnification ranges.. this scope comes with a 28mm LET EP.. the EPs i was looking for to buy were around 25 Euros.. but even the 28mm EP was available for the same amount.. does that mean that i shouldnt be getting these ones as they might be of the same quality as the stock EP? or could it be that the stock EP was of lets say 10 Euros worth and i should get the 28mm EP for 25 Euros as well? i hope im able to explain the dilema im in..

7. following andrews tutorial on EP selection, i short listed the following EP lengths for me.. scope focal length is 1000mm and its an f/5 system..

- 2x barlow..

- 28mm (low-power stock) for 36x and 72x

- 20mm (med-power) for 50x and 100x

- 10mm (hi-power) for 100x and 200x

i know the 100x is being repeated twice but im at a loss as to whether its good or bad..

7. since im planning to buy from Telescop Express store.. i couldnt find other stores in norway.. im totally baffled by their variety.. can you people PLEASE help me in selecting a few EPs from here? needless to say im tight one budget.. i could take out 25 Euros each for lets say 4 or 5 EPs.. but some of the EPs i saw were starting from 300+ Euros.. clearly not an option.. or should it be? i mean the entire OTA is costing me around 350 Euros.. ..

Teleskope - Zubehör - Okulare - Teleskop-Express: Astro-Shop + Fotografie + Naturbeobachtung

Weitwinkelokulare 1,25' ab 60° - Teleskop-Express: Astro-Shop + Fotografie + Naturbeobachtung

Okulare mit 2' Steckhülse ab 60° Gesichtsfeld - Teleskop-Express: Astro-Shop + Fotografie + Naturbeobachtung

im feeling so stupid that i dont have the know-how and im embarking out to buy an expensive item.. please bear with me..

thank you all.. this forum and you all have already been a great help..

asim sohail..

[Helen]

OK, here goes with some of the answers I hope!

1. why are telescopes made to work with 1.25" and 2" EPs? i mean why not a standard? either 1.25" or 2"..

I'm not sure in history how the 1.25 and 2 inch was decided upon, so can't help the why. The bigger eyepieces need more glass etc and so are heavier and more expensive. For smaller focal length eyepieces though there is no need to have the larger 2 inch format - and so having them in 1.25 format will be cheaper!

2. i am planning to buy a Skywatcher Explorer 200PDS.. the specs are confusing me.. it says it has a 2" crayford focuser with 1:10 dual speed transmission (ideal for astrophotography).. what is that supposed to mean? .. This means the focus is smooth and can be moved very small distances (that's what the 1:10 bit does) to achieve good focus.and does that mean that the scope accepts 2" EPs? it also says that a 1.25" reducer is included.. why 1.25"? does it mean that the scope can take 2" and 1.25" EPs? Yes, it can take 2 inch and 1.25 inch eyepieces. the stock EP is 28mm but doesnt mention the barrel size.. thats why im confused.. It will be 1.25 fitting i was looking to buy some 1.25" EPs but now im confused.. as to whether i should be looking for 2" EPs or 1.25" EPs.. For the moment I'd stick with a couple of good quality 1.25 eyepices.

3. i checked the prices of some 1.25" and 2" EPs.. and ive deduced that 2" EPs are a LOT more expensive than 1.25" ones.. why is this so? they are bigger, need more glass etc would be my guess

4. the description says that the 2" focuser can hold cameras of up to 2kg solidly.. does it mean that i wont be needing any T-Rings, etc? or do i still need them? I think this refers to the fact that the focuser tube won't slip, rather than being about the actual connection. Connect via t-rings is usually very solid.

5. when youre using this scope for astrophotography.. you do remove the EPs right? if im wrong could someone please clarify this to me? Generally yes (although it is possible to attach a camera to an eyepiece)

6. its been advised that the scope EPs are usually cheap and you should buy new ones in low, medium and high magnification ranges.. this scope comes with a 28mm LET EP.. the EPs i was looking for to buy were around 25 Euros.. but even the 28mm EP was available for the same amount.. does that mean that i shouldnt be getting these ones as they might be of the same quality as the stock EP? or could it be that the stock EP was of lets say 10 Euros worth and i should get the 28mm EP for 25 Euros as well? i hope im able to explain the dilema im in.. I think you should be budgetting to pay a little more for the eyepieces to get a noticeable step up. I'd suggest you try the provided ones first and then see what you need. Buying one or two better quality eyepieces and a barlow would be better than spreading your funds across more eyepieces.

7. following andrews tutorial on EP selection, i short listed the following EP lengths for me.. scope focal length is 1000mm and its an f/5 system..

- 2x barlow..

- 28mm (low-power stock) for 36x and 72x

- 20mm (med-power) for 50x and 100x

- 10mm (hi-power) for 100x and 200x

i know the 100x is being repeated twice but im at a loss as to whether its good or bad..

You could buy the barlow first and try that with the eyepiece that comes with the scope - that will gte you started.

7. since im planning to buy from Telescop Express store.. i couldnt find other stores in norway.. im totally baffled by their variety.. can you people PLEASE help me in selecting a few EPs from here? needless to say im tight one budget.. i could take out 25 Euros each for lets say 4 or 5 EPs.. but some of the EPs i saw were starting from 300+ Euros.. clearly not an option.. or should it be? i mean the entire OTA is costing me around 350 Euros.. .. you could also try buying eyepieces second hand - that would make your money go further.

Teleskope - Zubehör - Okulare - Teleskop-Express: Astro-Shop + Fotografie + Naturbeobachtung

Weitwinkelokulare 1,25' ab 60° - Teleskop-Express: Astro-Shop + Fotografie + Naturbeobachtung

Okulare mit 2' Steckhülse ab 60° Gesichtsfeld - Teleskop-Express: Astro-Shop + Fotografie + Naturbeobachtung

im feeling so stupid that i dont have the know-how and im embarking out to buy an expensive item.. please bear with me..

There's no problem with asking lots of questions, that's the way to learn (and other people will learn from the discussion that you start too!).

I hope this helps a bit

Helen

[Orion_the_Hunter]

Hi, as Helen says, you could look to buy second hand. Otherwise you will probably need to stretch your budget. Also it may be better to get 3 or 4 ep's rather than 4 or 5. Once you've got used to the scope and ep's a bit more you will know which focal lengths to go for.

Sorry that I probably haven't been much help.

Teleskop Express are very good, I got my scope from them, delivered to France very quickly.

[AweSIM]

Helen.. thank you so much for the prompt and detailed response.. you really clarified a lot of my concerns.. .. thank you.. .. now just a "few" follow up questions and remarks regarding your reply..

4. the description says that the 2" focuser can hold cameras of up to 2kg solidly.. does it mean that i wont be needing any T-Rings, etc? or do i still need them? I think this refers to the fact that the focuser tube won't slip, rather than being about the actual connection. Connect via t-rings is usually very solid.

thanks.. i had removed the T-Rings from my shopping list due to this.. ill get it back on..

5. when youre using this scope for astrophotography.. you do remove the EPs right? if im wrong could someone please clarify this to me? Generally yes (although it is possible to attach a camera to an eyepiece)

how come? and what purpose does it server to attach to an EP?

7. following andrews tutorial on EP selection, i short listed the following EP lengths for me.. scope focal length is 1000mm and its an f/5 system..

- 2x barlow..

- 28mm (low-power stock) for 36x and 72x

- 20mm (med-power) for 50x and 100x

- 10mm (hi-power) for 100x and 200x

i know the 100x is being repeated twice but im at a loss as to whether its good or bad..

You could buy the barlow first and try that with the eyepiece that comes with the scope - that will gte you started.

now THAT makes more sense.. .. a barlow plus 28mm stock will give me 36x and 72x.. good for now i guess..

next off.. im gonna ask some questions regarding filters.. when im done preparing a post.. will append to this one.. .. thanks a lot..

[AweSIM]

@orion_the_hunter.. thnx bro.. im of the same opinion that i might need to expand the budget.. it just didnt make sense to me.. when starting off.. i thought the OTA is the most important thing.. then it turned out that the mount is.. so much that SkyWatcher Explorer 200PDS is worth 40,000 PKR and NEQ6 Pro SynScan is worth 1,30,000 PKR.. now its turning out that EPs are really important too.. .. i mean how much am i to spend.. my family (having no interest in astronomy) already think im crazy in getting a "tripod" three times as expensive.. hehe.. if i ever get those 300 Euro EPs and tell them they cost as much as the OTA itself.. theyll flip for sure.. .. hehe..

[david o]

I'd be tempted not to buy anything for now and just use what came with the 'scope. With eyepiece time under your belt you'll know what needs replacing, or if there's a gap that needs filling.

As your 'scope is fast, at f/5, it'll be quite demanding on EPs. You'll be better off buying fewer, but better quality, EPs.

So you may want to think about getting only two good EPs and a decent 2x Barlow, effectively giving four different focal lengths and thus four different magnifications.

As a suggestion (all in 1.25" fitting) :-

* 32mm Plössl, giving ~31x (= 16mm with Barlow, giving ~63x)

* 11mm Plössl, giving ~91x (= 5.5mm with Barlow, giving ~182x)

What bit of kit ?

Well, TeleVue Plössls will work well in even the fastest 'scope and, 2nd hand, should be affordable. The Celestron Ultima 2x Barlow, again 2nd hand, will serve you well.

HTH

[AweSIM]

@david o.. thanks a lot.. that was precisely the kind of information i was looking for.. as in accessories available from the market that i should get.. .. thank a lot.. .. as a side note.. 2nd hand might not be an option for me.. .. cuz i wont be able to try on the EPs before buying.. itll be like.. send them over to pk.. ill take a look and if theyre ok.. good.. otherwise ill send em back.. doesnt work that way.. .. so ill be better off getting new ones that ill be sure of..

a few questions i had regarding filters..

1. solar filters.. i intend to do solar imaging too.. some filters i found on Telescop Express seemed smaller and some larger than 200PDS.. if i get one of these.. is it possible to use them? like maybe cut out a cardboard donut, fix the filter in it and mount the assembly on to the OTA? or something like that?

2. colored filters? do i really need them? im told colored ones are used to bring out detail.. but im told theyre more suitable for planetary viewing..

3. dso filters? the names confuse me.. HIII, UHC, etc.. im more interested in nebulae and galaxies and wide-field work.. which ones should i be looking for? or should i wait? which filters do you people have and how useful are they to you guys?

as for the kit.. i meant.. right now im getting the OTA only.. plus maybe a few EPs and some filters.. need help on that too.. .. the mount isnt an option RIGHT now.. im raising cash for it.. maybe in two months max.. cuz i can have that shipped or anybody can bring that here in baggage.. i cant take that risk with the OTA though.. so having it brought here thru a trusted friend whos been advised to be willing to sacrifice his life too to protect the scope.. ..

one thing im truly loving about this forum is how helping the people here are.. i mean nobody burns you away that this question has already been answered.. thread locked.. .. i mean yes.. us new comers should look around for answers before posting new, repetitive threads.. but if we could find answers so easily.. wed be pros already.. .. i thank you all people whove helped me out.. not only on this post.. but all the past stupid posts as well.. makes you awe.. how a person youve never even seen.. can be so willing to help out like a brother..

regards..

asim sohail..

pakistan..

[david o]

Asim, it's no problem

At some point we've all been beginners (I'm still a novice too... and will be for a long time!) and needed guidance or a helping hand.

Buying astro stuff 2nd hand usually isn't a problem, as most star-gazers really look after their kit. Just be careful where you buy it through. UK Astronomy Buy & Sell is generally well regarded so is the Buy & Sell section here on SGL (only visible to new members once you've accumulated 50 posts and been on the forum for over a month).

That said, be careful, there are always some bad apples out there.

I'd advise not to go mad on buying kit right at the start, take your time, learn the basics with the kit you get as standard, find out where your astronomy preferences lie and then focus on those. There's a lot to learn and experience before getting too involved or complicated. It'd be a shame for you to spend loads of cash on things that'll end up not getting used.

I guess I'm trying to say "don't try to run before you can walk". After all the night sky isn't going anywhere fast... it was there before us and will be there long after we're gone.

To answer your three questions I'd say leave those for now and only spend on them when you know that your astro-interest leads you to need them.

The only filter that I'd think of as a real "must have" is a strong(ish), neutral density moon filter. Maybe even a Light Pollution Reduction filter, if you live in an area with a fair bit of LP.

HTH

Hopefully I don't sound too discouraging, I really don't want to rain on your parade but for you to grow into the hobby and enjoy it

[jamespels]

Hi Asim, and welcome!

One question - do you wear glasses and, if so, is this just for focus or do you have astigmatism or other eye-shape issues? If it is just for power, you should be able to use your scope's focus. However, if you are like me and have an astigmatism, you wil need to wear your glasses while viewing - this can make a difference to the eye-pieces you can use. Plossls less that about 12mm do not have enough eye-relief (distance between the EP lens and your eyeball, in simple terms) for spectacle wearers and some other types are even worse. There are perfectly good alternatives around so this is not a problem but it is something you may need to consider.

[idlelimey]

Further to question 2 the DS part of 200PDS refers to 'Dual Speed'. You have a 1:1 focus and a slower, more precise 10:1 on a seperate dial. I have a 200P and am seriously considering a dual speed focuser. They cost about £100.

Point being, if I were buying again - I'd be sure to have a DS focuser.

Can anyone out there provide more feedback on DS focusers? I'm really interested but I'm not sure if it's worth shelling out for?

Many thanks.

[AweSIM]

@david o..

thanks a lot for that insight brother.. im thinking the same way after reading the last couple of posts.. get a FEW EPs.. and stick with them.. no need getting a whole box of EPs that ill never use..

about the filters.. i was thinking more in terms of nebulae filters like the UHC or HIII filters ive "heard" of.. but recently im beginning to think that moon filters and solar filters are a must too.. but LP filter? ive heard it depends on your local environment.. some filters work.. some dont.. how can i be sure itll work for me?

i live in the city and the skyglow here is TERRIBLE.. in fact i have to bring my cameras ISO down to below 200 and stop the aperture at f/7 to make sure exposures of about 1 or 2 minutes dont turn up bright orange.. but i make frequent trips to the northern areas where its almost excellent seeing.. i have a car so im hoping that transporting the scope and the mount wont be a bad experience..

what do you say? still LP filter? and if so which one? preferably ones available from Telescop Experts.. cuz ill be ordering from them.. and solar filters? which ones?

@jamespels..

thanks for the welcome brother.. i dont wear glasses.. my eyesight is slightly weak but i havent worn glasses in three years now.. im still living.. but like youve mentioned.. eye relief is important too.. so following david o advice in his 2nd last post.. ill be getting 10mm and 20mm EPs and a barlow to avoid having to get EPs with smaller focal lengths.. .. thanks for the tip..

@idlelimey..

thanks for the insight into DS focuser.. you helped clarify it more to me.. as for your question.. id try chipping in some responses ive had in the past threads.. i thought that DS is more of a luxury than necessity.. but it was remarked by a couple of people that yes it may be.. but its a very important thing to have.. and that if they were buying now.. theyd definitely buy the DS version.. ill locate the thread and post its link too..

thanks a lot to you guys..

asim sohail..

[Orion_the_Hunter]

I also think you should stick with the supplied ep's and maybe buy just one for now at about £30-40.

Best to build your collection slowly.

Also, don't rush out to buy a high magnification eyepiece.

Use of the supplied ones will tell you what is best.

[AweSIM]

@orion_the_hunter..

i agree with you dude.. .. i aint looking forward to buy short focal length EPs.. primarily cuz im more interested in DSOs instead of planets..

you guys have no idea how useful this post has been to me.. i hope the discussion helps others like me..

[BinocularSky]

I'm not sure in history how the 1.25 and 2 inch was decided upon,

I can tell you about the 1.25:

The old RAS thread was a 1.25" screw fitting; it was the same thread that was used on iron gas pipes at the time. It was used so that easily available hardware could be used for making telescope focusers. It evolved into the push-fit with locking screws (or rings) that we have today.

[ronin]

The 2" focusser is simply bigger, larger daimeter and thicker material. They say ideal for astrophotography simply because hanging a camera off of a 2" unit bends less then if you hang the same camera off of a 1.25" unit.

The "bend" isn't anything you can tell but as the scope tracks if the balance changes then perhaps the sensor could move a pixel or two owing to the weight.

As to eyepieces, if you want values try 8mm, 12mm and 32mm along with whatever comes with the scope. Think TS do some planetary ones at decent prices. Get one at a time. For the scope you have I would avoid the budget plossl's. If considering a barlow then you may have to get a good one, they are not exactly inexpensive either. A poor or mediocre barlow will not make the viewing pleasurable. I would hold off getting one for now.

A 300 Euro eyepiece, if you look you can get a lot higher then that.

2" eyepieces are BIG, very big. Stick with 1.25" eyepieces.

[AweSIM]

@tetenterre.. now that was a good piece of history for me.. .. now it figures.. .. thanks..

@ronin.. thanks for the very useful info.. i never thought of it this way.. youre right.. the camera target may move due to different loading conditions and smear the image even if you have an NEQ6.. and youd be blaming the mount.. not realizing its the 1.25" barrel thats causing the problems.. ..

as for your advice regarding the EPs.. thats.. well.. shocking.. im a novice after all.. i was thinking of getting 11mm.. 32mm.. 28mm (stock).. plus barlow..

- Tele Vue Plössl 11mm - 1,25' - 50° Gesichtsfeld

- Tele Vue Plössl 32mm - 1,25' - 50° Gesichtsfeld

- Tele Vue BLW-2125 - 2fach Barlow Linse - 1,25' - achromatisch

what do you think of these? good enough or not? they are definitely above my current budget.. but i think ill need an EP or two besides the stock 28mm.. even if one of them is around 28mm.. simply because i think the stock 28mm isnt good enough and that 200PDS is a fast scope.. i may be wrong.. if i am then please correct me..

asim sohail..

[Adrian]

My neighbour just got the 200pds - The skywatcher 28mm LET eyepiece with it is a 2 inch eyepiece and so won't fit in a 1.25" barlow

[banner001]

asim, remember that your EP is one half of the telescopes optics system, and as such needs decent kit.

if you buy a £20 EP it will look like a £20 EP, look at some baader hyperions, televues and some good plossl's.

as for what you will need, my advice it buy the telescope, look at some objects, decide what you would prefer them to look like (i.e. you might want more magniification, or wider FOV, or both combined) then buy the EP that does that modification.

[AweSIM]

@adrian.. ouch!.. didnt realize that.. and my apologize for writing the wrong EPs.. i was planning on the following ones..

- 28mm (2" stock)

- 40mm (1.25")

- 11mm (1.25")

this can give me the following magnifications..

- 25x --> 40mm

- 36x --> 28mm (stock)

- 50x --> 40mm + 2x barlow

- 91x --> 11mm

- 192x --> 11mm + 2x barlow

dont you think this is a decent range? even if the 2x barlow doesnt fit the 28mm stock EP?

@banner001.. i was initially looking at TS Optics EPs which were in the 25 - 30 GBP range.. i moved off to TeleVue EPs after being told to stay away from cheap EPs.. these are in the range of 85 - 100 GBP.. do you still think theyre cheap too? (this translates into 12,000+ PKR.. in comparison average monthly income in my country is around 40,000 PKR.. )..

but when all is said and done.. the fact remains that the EPs ARE pushing my budget up.. i am trying to balance my desires and my pocket.. im already delaying buying the mount for a month.. and am planning to get the OTA and EPs this month.. might well be that i settle for JUST the OTA this month.. mount next.. then finally EPs..

[AweSIM]

one thing thats been constantly bugging me.. would someone PLEASE make me understand.. why are DOBs so popular? to me they have more cons than pros..

+ cheap

+ bigger aperture

+ solid mount

- can not be used to track on equatorial mounts

- can not be used for astrophotography due to field rotation due to alt-azimuth mounts..

why is it then that im reading about so many DOB equipment reviews on this forum? agreed im a novice and have high ambitions like most novices about astrophotography and things i might never get to use it for.. but is the cost factor the only factor people look for in these systems? or have i missed something?

[John]

I would not buy a 1.25" 40mm eyepiece - the field of view will be small and it would hardly show you any more sky than the 28mm does - less if the 28mm is a 2" eyepiece.

If your budget is tight then you could just go for something around 12.5mm - a plossl will work quite well with your scope.

[AweSIM]

also.. i was looking to cut down on budget by leaving out a laser collimator.. ive read about how to collimate using diffraction rings in out-of-focus images of stars.. but so many people apparently take these collimators as an absolute must.. is it true? will i as a novice be unable to collimate without these items?

[John]

Dobs are popular because they are fantastic value scopes for the visual astronomy. Tracking is not difficult, the eyepiece / finder is always in a good position.

You are correct that they are not suitable for imaging but many astronomers (including myself) are just interested in visual observing.

[John]

I use a non-laser Cheshire collimation tool - I believe that it's more accurate than a low cost laser collimator. So the lasers are not essential.

[AweSIM]

@jahmanson.. err.. brother you just confused me.. how is a 40mm EP going to have a narrower FOW? i mean 28mm gives 36x.. 40mm gives 25x.. less magnification means wider FOW, right? thats what i thought before opting for 40mm.. for wide-field work.. ive read on the sticky i think on this forum about EPs.. that 1.25" has a narrower stop field than 2".. but still.. i think i need to learn a LOT more than i thought..

can someone also tell me.. how is it that 200P accepts both 1.25" and 2" EPs.. i mean if someone has come across an image showing the section of the focuser thatll be really helpful..

one other thing.. the 200P supports direct connection to an SLR via a T-Ring.. but its also possible to connect an SLR via an EP.. my questions..

1- what determines how big the image on the SLR sensor is going to be with a direct connection? since there is only one mirror and no EP..

2- how do you connect via the EP? and what purpose does it server? does it magnify the image?

3- how do you people who've been posting so many great astropics in the forum using SLRs connect your SLRs to your scopes?

please pardon me for asking so many questions.. especially those that have nothing to do with EPs which is the title of this thread.. im really sorry for being such an irritation.. .. but im thinking that when im done purchasing my scope.. ill compile everything ive learnt on this forum in the many threads i posted.. into ONE single thread.. god knows how much have you people added to my knowledge in the past few days.. i would love to give back to the community what i can..

asim sohail..