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#1 supertrucker

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Posted 22 April 2019 - 10:31 PM

 i started out with the orion spaceprobe 130st eq, i was not impressed with the build of the mount or how the reflector would loose collimation so easy, then there's the time spent manually working the eq mount searching the sky for whats to see. ok that part i enjoyed but i spent less time doing what i really wanted to do in the first place - more viewing less searching. after sweet talking the wife out of the permission to get a decent go-to mount i searched this forum and others - reviews and decided on the orion 150 cassegrain mak and a orion siruis pro az eq. i  bought each piece separately no kit stuff. so i was not stuck with kit lenses - diagonal - ect- the diagonal i ordered is the orion twist tight dielectric mirror star there wasn't a whole lot of reviews on it but the ones i did read were pleased with the product i will let you know what think about it after some use.. this cassegrain can take 2" eyepieces  so far i have only ordered 1 eyepiece a ES 30mm 82 degree i'm still trying to decide on about 3 more lenses plus a 2" x2 barlow i like what i hear about ES products but really i'm just looking for great eye relief wide enough for good clear viewing maybe a ES 18 or 24mm 2" 82 degree , ES 8.8mm 1.25" 82 degree , and a ES 4.7 1.25" 82 degree. i am open for suggestions what range of eyepieces that would make the most out of this gear? my wife really enjoyed the evenings out side and looking through the scope. i think that had a lot to do with her going along with this $$$$ upgrade. and hey if any of you have this 150mm cassegrain , orion sirius pro , or these lenses please tell me what you like or dislike about them. i'll go first, when i first heard you rarely have to collimate this type of scope i was half sold and then light weight portable compared other scopes with these qualities i think i'm going to like it. thanks for taking the time to read this if you have any tips or suggestions i need all the help i can get.



#2 aeajr

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Posted 22 April 2019 - 10:53 PM

I read through that block of text and am not sure of your question.    

 

Are you asking about eyepieces?  Do you have any eyepieces now?

 

I need a budget.  Eyepieces can be $30 or they can be $300.  What do you have to spend?

 

Are you looking for starter eyepieces that you might replace some time in the future or are you looking for best quality lifetime eyepieces?

 

This article may be helpful.

 

Telescope Eyepieces
https://telescopicwa...cope-eyepieces/


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#3 gnowellsct

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Posted 22 April 2019 - 11:40 PM

I think you should get a regular barlow not the 2".  Two inch eyepieces are best at providing wide fields of view.  You have an f/12 scope with 1800 mm focal length that can't really do wide fields well...it is at a disadvantage compared to the c8, for example, because of the smaller baffle tube (unless I am greatly mistaken).

 

Anyhow a Barlow is all about increasing magnification.  Increased magnification decreases the field of view.  To sum up, you would likely do very well with a 1.25" Barlow for mid range eyepieces (say 10 to 20mm focal length, or 180x down to 90x magnification--this would be in 1.25" format.  You don't really find commercial eyepieces in 2" format below about 20mm anyhow...the only one I know is the Nagler 17 T4 and it really has a dual purpose barrel that can go into either 1.25 or 2" diagonals).  Basically such a barlow would economize buying eyepieces under 10 mm.  

 

If you have some wide field 30 and 40 mm two inch eyepieces and are planning for using a 2" barlow for them then to get them to 15 and 20 mm respectively I think that is mechanically the wrong approach.  Just get two good 20 mm and 15 mm eyepieces and use a 1.25" barlow to make them into 10mm and 7.5 mm respectively.

 

A barlow is a good economy device when your selection of oculars is limited.  Once you get a full set of eyepieces you may not use it ever.  There are a few exceptions:

 

1.  You're doing solar h-alpha or planet photography.  The two inch format is a big help.

2.  You have purchased a zoom lens and want it to have a higher magnification range than what is designed into the zoom.  The Leica is a high end zoom, costs a bundle (there are more affordable options out there) but its range is 8.9 to 17.8 mm equivalent.  With the 4x zoom you get 2.2mm to 4.5 mm (very good ultra high magnification options) and with a 2x you get 4.5 to 8.9 which is the mid range magnifications.  You have infinite adjustment within these ranges so they take the place of many eyepieces.  It can be convenient but may or may not be cost effective and may or may not be as good as dedicated eyepieces depending on the choice you make.

 

Otherwise, if you just want the 2x capability, I'd suggest a 1.25" Barlow unless you truly and seriously want to barlow a massive 2" 30 or 40 mm eyepiece.  The pic below is what that can look like.  

 

Greg N

 

cff solar one barlow.jpg


Edited by gnowellsct, 22 April 2019 - 11:43 PM.


#4 csrlice12

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Posted 23 April 2019 - 11:58 AM

Also be aware the ES82 18mm has pretty tight eye relief.  Excellent optics, just short on eye relief.


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#5 supertrucker

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Posted 23 April 2019 - 12:07 PM

How about the 2" 24 82 degree?

#6 tony_spina

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Posted 23 April 2019 - 12:25 PM

How about the 2" 24 82 degree?

That has 17mm eye relief



#7 dr.who

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Posted 23 April 2019 - 03:11 PM

OK. Assuming a budget to afford them...

 

That 30mm is a great eyepiece but as noted above you will have to get your eye right down on top of it to see things. But when you do you will be moving your head around before you see the barrel of the eyepiece. That personally bugs me so I always go for the widest field of view I can. That eyepiece has it. If you hate seeing the barrel you will love it too. My 82* ES eyepieces (EP) always made me feel like I had fallen into the EP and was swimming in space. If the eye relief is not good for you then you will want to look at the Tele Vue Delos EP's. They have a barrel that can be adjusted to accommodate the eye relief you need. 

 

Do yourself a favor and skip the barlow. It reduces the amount of light coming in, puts more glass between your eye and the view from the scope, and a good one will cost you what a good EP will. Use the money instead to get another EP.

 

Speaking of EP's, you have a good one with the 30mm BUT you also have a very narrow field of view with that 150 Mak Cas. It is an f/12 with a focal length of 1,800mm. The 30mm may be wasted on that scope.  Using the formula to calculate magnification power (focal length of the telescope/mm of the EP or 1800/30) we see that you will get 60x magnification with the 30mm EP. Using the simple formula for field of view (Apparent field of view of the EP/magnification of the EP or 82/60) we see you will get a 1.37 (rounded) degree field of view. Not super wide. Which is what this EP would be used for. I would recommend the following:

 

1. Set the $279 you spent on the 30mm aside for something else. More on this in a minute

 

2. Buy the 18mm, 14mm or 11mm, and either 6.7 or 8.8mm 82 degree Explore Scientific (ES) EP's on sale right now. This gives you a nice range of powers with no Barlow to mess with the view. This will cost you $523 with the sale ES has right now on EP's. 

 

3. Take the $279 you saved on the 30mm and put it towards the ES 80mm Essentials FCD1 APO refractor. With the sale price on it right now this will only set you back an additional $360. It also comes with a 2" diagonal by the way. 

 

Let me explain why I am suggesting this. The AZ-EQ5 allows you to mount two telescopes side by side in alt/az mode. The 80mm will ride on the other side of the 150mm Mak. The 80mm will give you the super wide field views you are looking for with the 30mm EP using the 18mm and it will almost triple the field of view you get with the 150. Using the 18mm you get 26x magnification when you divide the 480mm focal length of the scope by the 18mm EP which translates to a whopping 3.15 degree field of view. So looking at big objects like large open clusters and the like will be great in the 80mm APO. You also now have two telescopes to use. Both that do two separate but complimentary things. The 150mm Mak for looking at small deep space objects (DSO) and planets and the 80mm APO for the big DSO and just panning around. A win win for not much more money. And the aforementioned EP list I gave you comes out. Lastly the 80mm APO comes with a lifetime transferable warranty. So if you sell it for something else down the road then the warranty transfers with the scope to the new owner. Lastly you get the fantastic customer service that ES provides. 


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#8 supertrucker

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Posted 23 April 2019 - 08:35 PM

 Dr Who -  thanks for all the suggestions skipping over the barlow for now. it's starting to make sense, paying extra for a wide field just to dilute and dim it down, for now i will stick with the 1.25" EP's. as for what EP,s i have? just the 30mm. i started out with a orion kit lens set, yeah kit for the price i guess it was ok but not even close to what i was looking for but i kept them anyway because by that time i decided i wanted the go-to mount and i would pass this orion spaceprobe 130st eq gear onto my grandson he is pretty good with tinkering around with gadgets and he took to it right away. for now i'm scopeless and mountless it should be here in a few days so i have plenty of time to research and decide what lenses to get. i'm sure i will spend a couple of weekends learning how to operate the mount, Aeajr - as for my budget i can afford 4 ES in the 82 degree range.maybe 5. you all are a lot of help saving us greenhorns from costly mistakes thanks a bunch!  


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#9 aeajr

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Posted 23 April 2019 - 10:39 PM

Just want to confirm the Optical tube.  Is this it?

https://www.telescop...c/14/p/9967.uts

 

Optical design
Maksutov-Cassegrain
Optical diameter 150mm
Focal length 1800mm
Focal ratio f/12.0
Resolving power 0.78arc*sec
Lowest useful magnification 51x
Highest useful magnification 300x

 

You say you have an ES 30 mm 82 degree - Excellent!

 

You can you can afford 4, maybe 5 ES 82s.   Excellent.   I have several of this series and like them in my Dob and my 1900 mm FL Mak.

 

300X in an 1800 mm scope would be a 6 mm.   

 

If your sky is anything like mine,  you will probably top out most evenings at 250X or lower.

 

240X would be 7.5 mm

 

So let's look at this set of ES eyepieces.

 

30 mm = 60X

 

14 mm = 128X

 

11 mm = 163X

 

8.8 mm = 204X

 

6.7 mm = 268X

 

That looks like a very nice set with a good spread of magnifications.  If you add a 1.25" 2X barlow for those higher mags that you would like to try but can rarely reach.

 

11mm + 2X barlow = 326X

 

You could skip the 6.7 mm and use the 2X barlow on the 14 mm for 

 

14 mm + 2X barlow = 256X

 

You could hold back on the 6.7 to see how often you can hit 256X.  If you can reach it often, then the 6.7 may be justified.

 

Now, if you like the ES 82s but would consider an alternative, I can highly recommend the Meade 5000 UWA 82 degree.  I have two of these.   Very similar optical performance to the ES82.  Larger screw up eye cup that some like and some don't.   But they are significantly less expensive.  I have the 20 mm and the 5.5 mm.

 

Meade 82 degree
https://www.astronom...pieces_c75.aspx

 

Meade 82 vs. ES 82

https://www.cloudyni...e-82-eyepieces/

 

 

My favorite eyepiece is my Baader Hyperion Zoom.   Not as wide as the 82s, but I use it far more than I use my 82 degree eyepieces.

 

 

THE ZOOM EYEPIECE INSTEAD OF OR IN ADDITION TO SINGLE FOCAL LENGTH EYEPIECES – This is my favorite eyepiece. 

 

The zoom is single eyepiece that effectively replaces a range of eyepieces.  Works like the zoom lens on a camera.   For example an 8 mm to 24 mm zoom would provide every magnification between them.  If I include a 2X barlow for use with the zoom it will provide every magnification from FROM 24 mm TO 4 mm without gaps.

 

The zoom sounds great, but there is a trade-off.  The field of view of the zoom runs from a narrower AFOV at the 24 mm range to a wider FOV at the 8 mm range.  So, like any approach, the zoom is a compromise.  I find that compromise quite acceptable when weighed against the benefits listed below, I prefer the zoom. 

 

For my 8" Orion XT8 Dob and my 5" Meade ETX 125 Mak, I use the Baader Hyperion Zoom 8-24 mm as my only eyepiece in the midrange.  I barlow it to extend it to the high range for the XT8.  But as I have a low power wide view 20 mm eyepiece I tend to use the zoom mostly in the 18 mm to 8 mm range for the midrange.  

 

Lower cost zoom – Celestron 8-24 – This was my first zoom.  Works well at the price and a good way to test your interest in zooms. $66
Higher priced Zoom – Baader Hyperion 8-24 mm – My main eyepiece in my Orion XT8i – $290
https://agenaastro.c...lanetarium.html

 

  • I never expected the zoom eyepiece to become my primary eyepiece, but it has.
  • With a zoom, the eyepiece seems to disappear as you just move in and out at will, no swapping, no thinking about eyepiece changes
  • The Celestron 8-24 zoom is good and comparable to my Plossl eyepieces
  • The Baader Hyperion is great and comparable to my Explore Scientific eyepieces
  • Watching doubles split as I rotate the barrel is wonderful
  • One filter serves over a wide range of magnifications, no screwing and unscrewing to try other eyepieces
  • Moving smoothly between small changes in magnification helps when seeing is not the best
  • I am always working at the optimum magnification for this target.
  • Sharing the view with others is easier, especially in my manual tracking Dob - I hand it over at low mag so it stays in the view longer.  They zoom back in to whatever magnification works best for them.
  • My eyepiece case has been greatly simplified
  • Kids love the zoom

When I observe, 90% of the time, in all of my scopes, I use one or two low power, then the zoom for the midrange.  Then I barlow the zoom for the high range if I need it, and that is all I use.  I have single FL eyepieces in my kit, but they are rarely used.



#10 supertrucker

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Posted 24 April 2019 - 07:12 AM

  yes that is the correct optical tube. this is very helpful information, i thought i understood at one time on how to take the scope's specifications and determine what eyepiece's match a scope. "NOT" i need to find a post that can give me a crash course in how to better understand the calculations , aperture , focal length , f ratio , i watched a video off the orion telescope website where there sales rep ken stated you could use up to a 38 mm 2" EP on this 150 mm mak, now my thinking is what he meant to say is you can use these low power EP'S but your still limited to higher power eyepieces. i need to find out what that number is? i looked at the meade 20mm series 5000 uwa, looks impressive. not sure if it's above my range of usefulness. the link you posted on eyepieces was helpful i'm going to go over it again so that i can soak it all in..Aeajr thanks again 


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#11 supertrucker

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Posted 24 April 2019 - 07:23 AM

 okay the link you posted yesterday on eyepieces is my crash course. i skimmed over it yesterday at work in between stops. i think this will get me in the know.


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#12 aeajr

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Posted 24 April 2019 - 07:30 AM

  yes that is the correct optical tube. this is very helpful information, i thought i understood at one time on how to take the scope's specifications and determine what eyepiece's match a scope. "NOT" i need to find a post that can give me a crash course in how to better understand the calculations , aperture , focal length , f ratio , i watched a video off the orion telescope website where there sales rep ken stated you could use up to a 38 mm 2" EP on this 150 mm mak, now my thinking is what he meant to say is you can use these low power EP'S but your still limited to higher power eyepieces. i need to find out what that number is? i looked at the meade 20mm series 5000 uwa, looks impressive. not sure if it's above my range of usefulness. the link you posted on eyepieces was helpful i'm going to go over it again so that i can soak it all in..Aeajr thanks again 

Telescope Eyepieces
https://telescopicwa...cope-eyepieces/

 

I am going to outline my eyepiece strategy.  After accumulating over 20 eyepieces I have focused in on this approach.   I have used this for my Orion XT8 8”/203 mm Dob, my 80 mm F5 refractor and my 127 mm F15 Mak.   

 

STRATEGY SUMMARY

  • One or two low power wide view eyepieces
  • One or two midrange eyepieces
  • Two to four high power eyepieces that include a plan for the top target magnification for that scope
  • Or, Zoom plus Barlow to cover mid range and high power
  • Planning to use a barlow can save you money

Selecting an Eyepiece - Orion telescope
This is a very general discussion of eyepieces and why there are a variety of designs
https://www.youtube....h?v=m7u9Q5hV7yc

 

 

Useful Formula -

 

Highest target top magnification =  aperture in mm X 2   So, for my 8" Dob, 203 mm aperture that would be 406X under exceptional good conditions.  For my 80 mm this would be 160X. For my 127 mm this would be 254X.   This is not a limit it is just a target to establish a range of magnifications.  

 

Power or Magnification = Focal Length Scope / Focal Length eyepiece

 

True Field of view  = Apparent Field of View eyepiece (AFOV) / magnification of eyepiece (This is a simplified formula that will provide a very close approximation under most circumstances)

 

Lowest power – often a spec provided by your telescope maker. But it can be whatever you like.   I would recommend something with an exit pupil of no more than 7 mm. 

 

Exit Pupil = Focal length of eyepiece / Focal ratio of scope. If your scope only takes 1.25” eyepieces, your lowest power widest view would be a 32 mm Plossl (50 degree AFOV) to define your lowest power.  If you have a 2” focuser you can likely go lower and wider.

 

For my 12" Dob, 1500 mm FL, 2" focuser I have a 38 mm 2" 70 degree and a 20 mm 2" 82 degree.  All the rest are 1.25".   

 

My other scopes are only 1.25" focusers.

 

 

Orion says the lowest practical power for your scope is 51X. I posted it in the specs.

 

Lowest useful magnification 51x

 

1800 mm FL / 51 = 35 mm.  So you don't want an eyepiece longer than 35 mm.   Your 30 is just fine. 

 

On a Newtonian, if you go too low power you start to see the shadow of the secondary mirror.  I am not sure if the MAK is the same.  I have used a 32 mm Plossl in my Mak with no shadow of the central spot.   Refractors don't have this concern. 



#13 supertrucker

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Posted 24 April 2019 - 08:31 AM

 okay thanks for the reassurance, someone had said the 30 mm would be to low power. i will stick with the ES 6.7 mm - 8.8 mm - 11 mm - 14 mm and maybe the mead 20 mm UWA that will narrow the gap between 14 mm and the 30 mm.



#14 aeajr

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Posted 24 April 2019 - 09:07 AM

Do the math. I don't think you need the 20, but nice to have.

#15 dr.who

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Posted 24 April 2019 - 10:18 AM

You really don’t need either the 30 or 20. The 18 plus the 14 or 11 and the 8.8 or 6.7 will do it for most of your needs. That money would really be better spent on that APO...

#16 aeajr

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Posted 24 April 2019 - 03:08 PM

Well, in truth you don't need any of it.  Food, clothing, shelter, air, safety.  Those are the necessities.

 

However, if I had that scope I would want something in the 30 to 35 mm range in a 68 degree AFOV or wider.

 

The 30 mm should yield:

 

1800 / 30 = 60X

 

82 degree AFOV / 60X = About a 1.3 degree FOV which is close to the max you are going to get on that scope. 

 

For each scope I have an eyepiece that maxes, or nearly maxes out the field of view.   With the 30/82 you have that. 

 

your next step at 18 mm would be

 

1800/20 = 90X  ( Meade 20 mm 82 degree)

 

1800/ 18 = 100X = ES 82 

Either of the above will work.  The 20 gives you a slightly better mag midpoint, but the 18 would be smaller and consistent with the rest. 

 

14 = 128X

 

11 mm = 163X

 

8.8 mm = 204X

 

6.7 mm = 268X



#17 Jond105

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Posted 24 April 2019 - 03:20 PM

In a 150 mak, I wouldn’t get an ES82 4.7. Not until you know about what you can max out on with your Sky conditions. It be rare for it to be useful on most observing nights. 


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#18 dr.who

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Posted 24 April 2019 - 04:16 PM

Well, in truth you don't need any of it.  Food, clothing, shelter, air, safety.  Those are the necessities.

 

However, if I had that scope I would want something in the 30 to 35 mm range in a 68 degree AFOV or wider.

 

The 30 mm should yield:

 

1800 / 30 = 60X

 

82 degree AFOV / 60X = About a 1.3 degree FOV which is close to the max you are going to get on that scope. 

 

For each scope I have an eyepiece that maxes, or nearly maxes out the field of view.   With the 30/82 you have that. 

 

your next step at 18 mm would be

 

1800/20 = 90X  ( Meade 20 mm 82 degree)

 

1800/ 18 = 100X = ES 82 

Either of the above will work.  The 20 gives you a slightly better mag midpoint, but the 18 would be smaller and consistent with the rest. 

 

14 = 128X

 

11 mm = 163X

 

8.8 mm = 204X

 

6.7 mm = 268X

 

Ed - You must have missed my post where I explained why a 80mm APO from ES was better than a 30mm EP for wide field. Using the 18mm in the 80mm you get a 3.15 degree FOV vs. the 1.37 degree FOV in the Mak with the 30mm. The 18-14/11-8.8/6.7 spread also is a better step in terms of magnification. Ideally the using the 18-11-6.7 setup. That gives you 90x, 163x, and 268x which are nice step increases in the Mak. They also do OK step wise in the 80mm with 26.6x, 43.6x, and 71.6x which are nice steps for a wide field scope.

 

It is downright silly to spend the money for a 30mm 82 degree when for just a few hundred more you can have a second scope that will give you truly wide field views with the same EP's you would also use in the Mak for good detailed views of objects. Especially since he has a mount that is designed to have two scopes on it. Plus down the road if he wants a true "grab and go" for quick views he can get the Explore Scientific Twilight 1 for a few hundred dollars, add a Nexus DSC with encoders to it, and have a very nice push to G&G rig as well.


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#19 dr.who

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Posted 24 April 2019 - 04:19 PM

In a 150 mak, I wouldn’t get an ES82 4.7. Not until you know about what you can max out on with your Sky conditions. It be rare for it to be useful on most observing nights. 

 

I agree. At one point I had the entire 82 degree line up of EP's. I *RARELY* used the 4.7 though it would see occasional use on planets. It made things really dark and seeing was rarely good enough to support it. I also *RARELY* used the 24mm (This was before the 30mm came out) because it was so big and heavy I would have to rebalance the scope when I switched out EP's. With the 18mm I never had to do this. 


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#20 Jond105

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Posted 24 April 2019 - 04:26 PM

I agree. At one point I had the entire 82 degree line up of EP's. I *RARELY* used the 4.7 though it would see occasional use on planets. It made things really dark and seeing was rarely good enough to support it. I also *RARELY* used the 24mm (This was before the 30mm came out) because it was so big and heavy I would have to rebalance the scope when I switched out EP's. With the 18mm I never had to do this. 

I agree with the 18mm. Last night I went out with my scope, and never once touched the 30 or 24. Started with the 18 and went up from there on all targets without a huge shift in balance. 


Edited by Jond105, 24 April 2019 - 04:27 PM.


#21 aeajr

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Posted 24 April 2019 - 05:29 PM

Ed - You must have missed my post where I explained why a 80mm APO from ES was better than a 30mm EP for wide field. Using the 18mm in the 80mm you get a 3.15 degree FOV vs. the 1.37 degree FOV in the Mak with the 30mm. The 18-14/11-8.8/6.7 spread also is a better step in terms of magnification. Ideally the using the 18-11-6.7 setup. That gives you 90x, 163x, and 268x which are nice step increases in the Mak. They also do OK step wise in the 80mm with 26.6x, 43.6x, and 71.6x which are nice steps for a wide field scope.

 

It is downright silly to spend the money for a 30mm 82 degree when for just a few hundred more you can have a second scope that will give you truly wide field views with the same EP's you would also use in the Mak for good detailed views of objects. Especially since he has a mount that is designed to have two scopes on it. Plus down the road if he wants a true "grab and go" for quick views he can get the Explore Scientific Twilight 1 for a few hundred dollars, add a Nexus DSC with encoders to it, and have a very nice push to G&G rig as well.

I was not aware that that was a two scope mount.  I have pretty much ignored the mount.

 

It is my understanding that he owns the Mak and is trying to fit it out. It is also my understanding he already owns the 30 mm 82, so that is a done deal.  So suggesting an APO instead of the 30 mm requires him to sell the 30 mm at a loss. 

 

I say stick with the 30 mm.   Keep an eye on the APO for the future.  



#22 Starkid2u

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Posted 25 April 2019 - 04:18 AM

I read through that block of text and am not sure of your question.    

 

Are you asking about eyepieces?  Do you have any eyepieces now?

 

I need a budget.  Eyepieces can be $30 or they can be $300.  What do you have to spend?

 

Are you looking for starter eyepieces that you might replace some time in the future or are you looking for best quality lifetime eyepieces?

 

This article may be helpful.

 

Telescope Eyepieces
https://telescopicwa...cope-eyepieces/

I didn't get anything he said, either.

 

STARKID2U



#23 dr.who

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Posted 25 April 2019 - 11:42 AM

I was not aware that that was a two scope mount.  I have pretty much ignored the mount.

 

It is my understanding that he owns the Mak and is trying to fit it out. It is also my understanding he already owns the 30 mm 82, so that is a done deal.  So suggesting an APO instead of the 30 mm requires him to sell the 30 mm at a loss. 

 

I say stick with the 30 mm.   Keep an eye on the APO for the future.  

 

I believe the 30 is on order and is thus cancelable. If he can't return it or cancel the order then it is what it is and the APO should wait.




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