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Barlow recommendation?

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#1 rhetfield

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Posted 15 September 2021 - 12:33 PM

The scope is a 130mm/F5 reflector.  I currently have two barlows: a celestron x-cel lx 2x and whatever came in the cheap fry's kit (appears to be a celestron omni 2x).  I use the lens element out of the omni as a1.5x multiplier.  The x-cel provides better images, but the lens element is not threaded to allow use as a 1.5x.  I find that I rarely use the 2x, as it is too much for my scope with my high power eyepiece (a 4.5mm) and 2x barlow on my other eyepieces just duplicates what I already have.  The 1.5x equivalent sees much more use due to not duplicating eyepieces and it provides the maximum useful magnification on the planets.

 

The question is what can I get that will replace at least the 1.5x (or ideally both) barlow and have performance at least equal to the x-cel barlow?


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#2 MisterDan

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Posted 15 September 2021 - 01:32 PM

Do you have a target budget?

 

https://agenaastro.c...der-nav-sw.html

 

https://www.sieberto...ows.html#Ad 1b0

 

For "sub-2x" options and a 1.25-inch focuser, I'd start with those.  There aren't many other options, anyhow.

 

As for other "short" 2x Barlows currently available with removable threaded cells (that match standard filter threads), most will be comparable.  In fact, most are made by the same few manufacturers.

 

Older Japan-made Barlows can be very good (and inexpensive), but many utilize longer (negative) focal ratios, so their behavior when attached to an eyepiece barrel (i.e. much closer to the eyepiece field lens(es)) may vary.  The Meade 126 has been around for decades and is a very good shorty.  Japan-made 126s are common on the used market, and they may work well when attached to an eyepiece (assuming the threads allow it).

 

-Hope that helps. Best wishes.

Dan


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#3 Frenchy

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Posted 15 September 2021 - 01:41 PM

Brandon magic dankin 1.5x.

 

I have both the 1.5x and 1.25x and have been very pleased with them. 



#4 Thomas_M44

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Posted 15 September 2021 - 01:42 PM

If 1.25” eyepiece compatibility only isn’t a problem, and $215 is in your budget, you almost won’t won’t find anything of superior (or equal) quality in that magnification range to the excellent Nikon EiC-16 Barlow:

 

https://agenaastro.c...der-nav-sw.html

 

Presently 4 in stock at Agena.

 

Ask any experienced observer here in CN’er  owns one of these—they are tops.


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#5 MrJones

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Posted 15 September 2021 - 02:30 PM

At the other end of pricing, I'm still really liking my Svbony 3x SV137 that is about $20. I did have to blacken inside to get rid of some reflections from unblackened areas.

 

I've bought and sold many Barlows such as TV 2x, Celestron Ultima, GSO 2.5x and my current X-cel 2x and Baader Q 2.25x just didn't win me over.

 

The Svbony provides a nice sharp 3x and the bottom element does unscrew to fit 1.25" EPs and seems to be about 1.5x. More testing tonight hopefully.



#6 sevenofnine

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Posted 15 September 2021 - 06:33 PM

Rather than a barlow, consider getting a decent zoom eyepiece. The Celestron 24-8mm zoom allows you to see what power is best given the sky conditions that change every night. Far more useful than a barlow IMO. Best of luck to you and your decision! waytogo.gif



#7 pregulla

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Posted Yesterday, 12:47 AM

I second zoom suggestion. There are plenty of options at affordable prices . More convenient, more flexible and will give better performance than using 1.5x on your eyepieces.

#8 Shinzawai

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Posted Yesterday, 06:03 AM

From what I deducted and got from people way more knowledgeable about it than me, and in the spirit of paying it forward;

 

In rising quality, at the bottom are 'shorty' barlows (best avoided), normal barlows and then PowerMates and some other equivalents (e.g. APM telecentrics).

 

You want it cheaper but perfectly fine?

GSO 2x ED or maybe Baader Q

 

You want a higher quality lens?

TeleVue 2x

 

You want all bells & whistles? (telecentric, parfocal)

TeleVue 2x PowerMate

 

Things to remember, the Barlow is a relatively simple design and has weak power, so even a lower cost one can be good enough.

 

And then there's this;

 

On the Barlow vs power mate debate: Al Nagler himself says that for a scope that doesn't use a diagonal, such as a newt, the barlow is just as good as the powermate. The powermate was designed for scopes using a diagonal where it corrects for problems caused by the diagonal.

 

For use with medium to short focal length ep's the change in eye relief caused by a barlow is minimal, maybe an extra mm or so, so it's not really noticeable. If you are going to barlow a long focal length ep for example a 30mm then the change will be greater and you may find a powermate would be the answer.



#9 rhetfield

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Posted Yesterday, 09:05 AM

Rather than a barlow, consider getting a decent zoom eyepiece. The Celestron 24-8mm zoom allows you to see what power is best given the sky conditions that change every night. Far more useful than a barlow IMO. Best of luck to you and your decision! waytogo.gif

 

 

I second zoom suggestion. There are plenty of options at affordable prices . More convenient, more flexible and will give better performance than using 1.5x on your eyepieces.

Couple problems with the zoom option for me:

 

- My scope has a helical focuser and it is generally reported that using the zoom with the helical focuser is a bit of a nuisance.

 

- More importantly, an 8-24 zoom - even if paired with a 2x barlow - just gets me to the lower end of the planetary viewing range that I am looking to improve on my smallish scope.  I am specifically looking to improve the optics I use for my 3mm equivalent.  If someone came up with a good zoom that could run from 2mm to 6mm, then that would be an option.

 

-I do separately need to look into my mid range and low magnification options.  The 10mm Kellner that came with the scope is especially bad around the edges.  A 24-8 zoom might be an option for that, but I would still need to consider something with more FOV to replace my 25mm.  If the zoom got 60 degrees at the 24mm end, that would be ideal, but that wouldn't be the case.



#10 rhetfield

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Posted Yesterday, 09:15 AM

Do you have a target budget?

 

https://agenaastro.c...der-nav-sw.html

 

https://www.sieberto...ows.html#Ad 1b0

 

For "sub-2x" options and a 1.25-inch focuser, I'd start with those.  There aren't many other options, anyhow.

 

As for other "short" 2x Barlows currently available with removable threaded cells (that match standard filter threads), most will be comparable.  In fact, most are made by the same few manufacturers.

 

Older Japan-made Barlows can be very good (and inexpensive), but many utilize longer (negative) focal ratios, so their behavior when attached to an eyepiece barrel (i.e. much closer to the eyepiece field lens(es)) may vary.  The Meade 126 has been around for decades and is a very good shorty.  Japan-made 126s are common on the used market, and they may work well when attached to an eyepiece (assuming the threads allow it).

 

-Hope that helps. Best wishes.

Dan

The Siebert Optics 1.5x and 1.6x barlows look like the most likely option so far.  I like that even the cheaper version is geared towards faster scopes.  The price is a bit higher than I was hoping for (The scope w/base currently retails for only $250 (I paid $200 a couple years back)) but is not unreasonable.

 

I revisited my current barlows last night.  I tried both 2x barlows with my 4.5mm on the double double.  This gave me about 290x at an exit pupil of 0.45mm.  The individual stars (airy disk and all) were clearly crisper and better defined (and split) with the x-cel barlow than with the other barlow (that one produced an image that was a bit mushy).



#11 MisterDan

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Posted Yesterday, 09:34 AM

The Siebert Optics 1.5x and 1.6x barlows look like the most likely option so far.  I like that even the cheaper version is geared towards faster scopes.  The price is a bit higher than I was hoping for (The scope w/base currently retails for only $250 (I paid $200 a couple years back)) but is not unreasonable.

 

I revisited my current barlows last night.  I tried both 2x barlows with my 4.5mm on the double double.  This gave me about 290x at an exit pupil of 0.45mm.  The individual stars (airy disk and all) were clearly crisper and better defined (and split) with the x-cel barlow than with the other barlow (that one produced an image that was a bit mushy).

I thought I would clarify one of my notes, although my guess is, you caught it just fine:

"As for other "short" 2x Barlows currently available with removable threaded cells (that match standard filter threads), most will be comparable."  I meant, comparable to one another - not necessarily the Siebert and/or Nikon units grin.gif .

 

If you're managing good fidelity at 290x in a 130, that's a fair indicator of well-collimated and quality optics (and good seeing, that night).waytogo.gif

 

Best wishes and luck.

Dan



#12 rhetfield

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Posted Yesterday, 10:39 AM

If you're managing good fidelity at 290x in a 130, that's a fair indicator of well-collimated and quality optics (and good seeing, that night).waytogo.gif

 

I suppose it is all relative.  The double double is a forgiving enough target that pushes the scope enough to provide a decently "digital" pass/fail.  Nothin is going to make any of the planets look good at 290x in my skies - about 200x is the most I have ever managed.  With any sort of decent sky and good collimation, I can split it cleanly, but just barely.  If optics, collimation, or sky is off, it is easily noticeable.  That is how I know I need a better 1.5x barlow option (or good, well corrected 3mm eyepiece).



#13 aeajr

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Posted Yesterday, 11:16 AM

AWB Onesky - 5", F5 reflector
- Skywatcher super MA 25mm & 10mm
- Celestron X-Cel 5mm, 2x Barlow
- 1000 Oaks LP2 UHC
- Degree circles
- Celestron Omni(?) Barlow lens element (1.5x)

 

Based on your signature, this is what you have.   

 

I would not be looking at a Barlow, I would be looking at eyepieces.   Those eyepieces are OK as package eyepieces but I would not build around them.  You have taken them about as far as they will go.

 

I don't know what you know about eyepieces so let me start with two resources.  

 

Understanding Telescope Eyepieces- There are recommendations, based on budget,
but the meat of the article is about understanding the considerations and specifications
to know when selecting eyepieces.
https://telescopicwa...cope-eyepieces/

 

Understanding and using a Barlow Lens
https://telescopicwa...ens-and-how-to/

 

 

Eyepieces - I have no idea of your budget but I would look at the AT Paradigm series or the Agena Astro Dual ED series which are the same eyepiece. 

https://www.astronom...iece_series=478

 

 

Discussion about Paradigm eyepieces
https://www.cloudyni...s/#entry8229760

 

 

I am a HUGE zoom eyepiece advocate.   I have the Baader Hyperion, Celestron and SVBony zooms.   My zoom eyepieces get more sky time than my single FL eyepieces. 

 

Depending on your budget I would suggest the Celestron or the Baader Hyperion 8-24 zoom.   In a 2X Barlow that takes you to 4 mm/162X, the zoom takes you to a good planetary magnification for this scope.   If you want to explore higher, then you can look at a 3X Barlow which will take you to 240X which might be good for the Moon on good nights.      

 

With the zoom, a 1.5X, 2X and 3X Barlow you have the full range of the scope covered.   Add a 32 mm Plossl for low power wide view and you are done.  

 

After that you are looking at single FL eyepieces of 60 degree AFOV or wider to expand your options.  I have a full range of 82 degree to complement my zooms. 


Edited by aeajr, Yesterday, 11:22 AM.

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#14 rhetfield

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Posted Yesterday, 12:25 PM

AWB Onesky - 5", F5 reflector
- Skywatcher super MA 25mm & 10mm
- Celestron X-Cel 5mm, 2x Barlow
- 1000 Oaks LP2 UHC
- Degree circles
- Celestron Omni(?) Barlow lens element (1.5x)

 

Based on your signature, this is what you have.   

 

I would not be looking at a Barlow, I would be looking at eyepieces.   Those eyepieces are OK as package eyepieces but I would not build around them.  You have taken them about as far as they will go.

 

I don't know what you know about eyepieces so let me start with two resources.  

 

Understanding Telescope Eyepieces- There are recommendations, based on budget,
but the meat of the article is about understanding the considerations and specifications
to know when selecting eyepieces.
https://telescopicwa...cope-eyepieces/

 

Understanding and using a Barlow Lens
https://telescopicwa...ens-and-how-to/

 

 

Eyepieces - I have no idea of your budget but I would look at the AT Paradigm series or the Agena Astro Dual ED series which are the same eyepiece. 

https://www.astronom...iece_series=478

 

 

Discussion about Paradigm eyepieces
https://www.cloudyni...s/#entry8229760

 

 

I am a HUGE zoom eyepiece advocate.   I have the Baader Hyperion, Celestron and SVBony zooms.   My zoom eyepieces get more sky time than my single FL eyepieces. 

 

Depending on your budget I would suggest the Celestron or the Baader Hyperion 8-24 zoom.   In a 2X Barlow that takes you to 4 mm/162X, the zoom takes you to a good planetary magnification for this scope.   If you want to explore higher, then you can look at a 3X Barlow which will take you to 240X which might be good for the Moon on good nights.      

 

With the zoom, a 1.5X, 2X and 3X Barlow you have the full range of the scope covered.   Add a 32 mm Plossl for low power wide view and you are done.  

 

After that you are looking at single FL eyepieces of 60 degree AFOV or wider to expand your options.  I have a full range of 82 degree to complement my zooms. 

One of the eventual goals is to get rid of the Super MA's that came with the scope.  The 10mm does poorly around the edges and the 25mm is only OK and does not have much FOV. 

 

While a 32mm Plossl is certainly a way to go, I live under a lot of light pollution and think I might do better with a shorter, wider EP for contrast.  The x-cel or paradigm 25mm/60 deg EP's would get close to the theoretical maximum FOV for the scope (the 32mm plossl might actually vignette a little).  I might even be tempted to try a WO 20 Swan (72 deg) if I become convinced it would perform well in an F5.  Not sure I want to spend on anything more costly than those though.  At some point, now that in person star parties are starting up again, I do want to see if anybody has any wide eyepieces I can look through - I have not looked through anything wider than 60 deg.

 

I have not yet decided what way I might replace the 10mm with.  Going with more x-cels like the 7mm and 9mm would allow me to get rid of the parfocal rings on everything.  However, it might make sense to get the zoom instead.

 

All of this still leaves me with the question of what to do about planetary.  The xcel 5mm (reportedly a 4.5mm) has been my main planetary eyepiece and performs well.  However, in my small scope, it is at the lower end of what I know I can do.  Getting down to a 3mm is probably approaching the upper limit of what both the scope and sky in my area can support for planetary.  I have had some OK views at that level and even a few rare good views.  However, I do know that the barlow I am using to get there does not perform as well as the x-cel 2X does.  That is hurting the view some. 

 

The 3x barlow with the zoom would be an option, but it would be even more heavy and cumbersome than what I am using now for the little scope.  Getting a good 3mm would also be an option, but I suspect that one that will work in an F5 for a reasonable price would be hard (any thoughts on the paradigm 3mm in an F5?).  In the end, the question would be which path would give the best view of planetary detail.


Edited by rhetfield, Yesterday, 12:29 PM.


#15 SteveG

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Posted Yesterday, 03:22 PM

Do not get a zoom with that scope!

 

I tried it and it was more miserable than I thought it would be.



#16 SteveG

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Posted Yesterday, 03:28 PM

One of the eventual goals is to get rid of the Super MA's that came with the scope.  The 10mm does poorly around the edges and the 25mm is only OK and does not have much FOV. 

 

While a 32mm Plossl is certainly a way to go, I live under a lot of light pollution and think I might do better with a shorter, wider EP for contrast.  The x-cel or paradigm 25mm/60 deg EP's would get close to the theoretical maximum FOV for the scope (the 32mm plossl might actually vignette a little).  I might even be tempted to try a WO 20 Swan (72 deg) if I become convinced it would perform well in an F5.  Not sure I want to spend on anything more costly than those though.  At some point, now that in person star parties are starting up again, I do want to see if anybody has any wide eyepieces I can look through - I have not looked through anything wider than 60 deg.

 

I have not yet decided what way I might replace the 10mm with.  Going with more x-cels like the 7mm and 9mm would allow me to get rid of the parfocal rings on everything.  However, it might make sense to get the zoom instead.

 

All of this still leaves me with the question of what to do about planetary.  The xcel 5mm (reportedly a 4.5mm) has been my main planetary eyepiece and performs well.  However, in my small scope, it is at the lower end of what I know I can do.  Getting down to a 3mm is probably approaching the upper limit of what both the scope and sky in my area can support for planetary.  I have had some OK views at that level and even a few rare good views.  However, I do know that the barlow I am using to get there does not perform as well as the x-cel 2X does.  That is hurting the view some. 

 

The 3x barlow with the zoom would be an option, but it would be even more heavy and cumbersome than what I am using now for the little scope.  Getting a good 3mm would also be an option, but I suspect that one that will work in an F5 for a reasonable price would be hard (any thoughts on the paradigm 3mm in an F5?).  In the end, the question would be which path would give the best view of planetary detail.

The 25/60 is an excellent idea for your low power views.

I would get the 9 XL to go with it, or the 8 mm Paradigm.

For a good 3x barlow, look at the Orion Trimag. When I tested barlows it was easily my best 3x (better than the TV). Its magnification is about 2.9x.



#17 aeajr

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Posted Yesterday, 03:31 PM

One of the eventual goals is to get rid of the Super MA's that came with the scope.  The 10mm does poorly around the edges and the 25mm is only OK and does not have much FOV. 

 

While a 32mm Plossl is certainly a way to go, I live under a lot of light pollution and think I might do better with a shorter, wider EP for contrast.  The x-cel or paradigm 25mm/60 deg EP's would get close to the theoretical maximum FOV for the scope (the 32mm plossl might actually vignette a little).  I might even be tempted to try a WO 20 Swan (72 deg) if I become convinced it would perform well in an F5.  Not sure I want to spend on anything more costly than those though.  At some point, now that in person star parties are starting up again, I do want to see if anybody has any wide eyepieces I can look through - I have not looked through anything wider than 60 deg.

 

I have not yet decided what way I might replace the 10mm with.  Going with more x-cels like the 7mm and 9mm would allow me to get rid of the parfocal rings on everything.  However, it might make sense to get the zoom instead.

 

All of this still leaves me with the question of what to do about planetary.  The xcel 5mm (reportedly a 4.5mm) has been my main planetary eyepiece and performs well.  However, in my small scope, it is at the lower end of what I know I can do.  Getting down to a 3mm is probably approaching the upper limit of what both the scope and sky in my area can support for planetary.  I have had some OK views at that level and even a few rare good views.  However, I do know that the barlow I am using to get there does not perform as well as the x-cel 2X does.  That is hurting the view some. 

 

The 3x barlow with the zoom would be an option, but it would be even more heavy and cumbersome than what I am using now for the little scope.  Getting a good 3mm would also be an option, but I suspect that one that will work in an F5 for a reasonable price would be hard (any thoughts on the paradigm 3mm in an F5?).  In the end, the question would be which path would give the best view of planetary detail.

I don't have your scope, but I do have an Orion SkyScanner 100, a tabletop Dob, that I use primarily as a loaner.  The loaner eyepiece set is a 25 mm Plossl, an SVBony 7-21 Zoom and a 2X Barlow.  Pretty much covers the range for that scope for people who borrow the scope.  Later, as they gain some experience, I give them a 3X Barlow to use with the zoom.  If I go shorter than 25 mm on that F4 scope I start to get a shadow of the secondary mirror, so no 32 mm on that one. 

 

 

The 32 Plossl I suggested for you would be to have an eyepiece that maxes out your field of view.  That 32 takes you about as wide as that scope can go for about $35.  Will take you to about 21X and 2.3 degree FOV.  Large enough to see the Pleiades, but not wide enough to take in all of the Andromeda Galaxy or the North America Nebula.

 

Fixed FL vs. Zoom.   For me it is not either/or but which to get first.  I have 3 zooms and a full set of 82 degree.  I use them all.

 

Planetary - I don't think in terms of planetary vs. DSO.  I look at a range of mags and then use them to best effect on whatever I am viewing.   

 

Here is an example of my eyepiece set for my AT102ED, probably the scope that is closest to yours in aperture and focal length.  I built this set up over 4 years.  This scope takes 2" eyepieces, but if it only took 1.25" then a 32 mm Plossl would be the first eyepiece on the chart, for 2.2 degree FOV. 

 

The bolded ones are the most used in this scope. I use the same eyepieces set in all of my scopes except I tend to use the Celestron zoom in my 1.25" focuser scopes just because it seems to feel better in the smaller scopes. 

 

 

Astro Tech AT102ED Refractor 102 mm/714mm  F7
Resolving power -  1.1 arc seconds

 

AA SWA 38 mm/70               19X and   3.7 degrees FOV   EP 5.4 mm  2”
Meade  20 mm/82                 36X and   2.2 degrees            EP 2.8      2”

 

ES       14 mm/82                   51X and   1.6 degrees         
ES        11 mm/82                  65x  and   1.2 degrees
ES       8.8 mm/82                  81X and   1.0 degrees  
ES       6.7 mm/82                 106X and    .7 degrees         
Meade 5.5 mm/82                 129X and    .6 degrees         
ES       4.7 mm/82                 152X and    .5 degrees      
    
ES       8.8+2XB                    162X and    .5 degrees
ES       6.7+2XB                     212X and   .4 degrees

 

Baader Hyperion 8-24  zoom 30X to 90X
Baader Hyperion 8-24+1.5XB   45C to 135X
Badder Hyperion 8-24+2XB     60X to 180X
Baader Hyperion 8-24+2.5XB  75X to 225X

 

My typical observing session starts with the 38 or 20 mm as finders and to see large expanse of the sky.   Then I go to the Baader Hyperion Zoom.   If I am working on planets, globular clusters or splitting doubles, I will likely drop the zoom into the 2X right away as I will be working at higher mags.  Or I might go to the 6.7, 5.5 and 4.7.   

 

If I was observing the Moon, where I am likely to be able to push higher, I will drop the zoom into the 2.5X Barlow.   I have a 3X but almost never use it. 

 

While I can clearly take the scope higher, I rarely go over 152X on planets as I find the atmosphere will start to degrade the image.  I will test higher, but usually drop back.   Testing higher is very easy to do with the zoom.  A little more effort with the single FL eyepieces, but the single FL do give me a wider FOV for more drift time. 


Edited by aeajr, Yesterday, 03:44 PM.


#18 SteveG

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Posted Yesterday, 03:39 PM

I don't have your scope, but I do have an Orion SkyScanner 100, a tabletop Dob, that I use primarily as a loaner.  The loaner eyepiece set is a 25 mm Plossl, an SVBony 7-21 Zoom and a 2X Barlow.  Pretty much covers the range for that scope for people who borrow the scope.  Later I have them a 3X Barlow to use with the zoom.  If I go shorter than 25 mm on that F4 scope I start to get a shadow of the secondary mirror, so no 32 mm on that one. 

 

 

The 32 Plossl I suggested for you would be to have an eyepiece that maxes out your field of view.  That 32 takes you about as wide as that scope can go for about $35.  Will take you to about 21X and 2.3 degree FOV.  Large enough to see the Pleiades, but not wide enough to take in all of the Andromeda Galaxy or the North America Nebula.

 

Fixed FL vs. Zoom.   For me it is not either/or but which to get first.  I have 3 zooms and a full set of 82 degree.  I use them all.

 

Planetary - I don't think in terms of planetary vs. DSO.  I look at a range of mags and then use them to best effect on whatever I am viewing.   

 

Here is an example of my eyepiece set for my AT102ED, probably the scope that is closest to yours in aperture and focal length.  I built this set up over 4 years.  This scope takes 2" eyepieces, but if it only took 1.25" then a 32 mm Plossl would be the first eyepiece on the chart.

 

Astro Tech AT102ED Refractor 102 mm/714mm ED Refractor F7
Resolving power -  1.1 arc seconds

 

AA SWA 38 mm/70               19X and   3.7 degrees FOV   EP 5.4 mm  2”
Meade  20 mm/82                 36X and   2.2 degrees            EP 2.8      2”

 

ES       14 mm/82                   51X and   1.6 degrees         
ES        11 mm/82                  65x  and   1.2 degrees
ES       8.8 mm/82                  81X and   1.0 degrees  
ES       6.7 mm/82                 106X and    .7 degrees         
Meade 5.5 mm/82                 129X and    .6 degrees         
ES       4.7 mm/82                 152X and    .5 degrees          
ES       8.8+2XB                    162X and    .5 degrees
ES       6.7+2XB                     212X and   .4 degrees

 

Baader Hyperion 8-24  zoom 30X to 90X
Baader Hyperion 8-24+1.5XB   45C to 135X
Badder Hyperion 8-24+2XB     60X to 180X
Baader Hyperion 8-24+2.5XB  75X to 225X

 

My typical observing session starts with the 38 or 20 mm as finders and to see large expanse of the sky.   Then I go to the Baader Hyperion Zoom.   If I am working on planets, globular clusters or splitting doubles, I will likely drop the zoom into the 2X right away as I will be working at higher mags.  Or I might go to the 6.7, 5.5 and 4.7.   

 

If I was observing the Moon, where I am likely to be able to push higher, I will drop the zoom into the 2.5X Barlow.   I have a 3X but almost never use it. 

 

While I can clearly take the scope higher, I rarely go over 152X on planets as I find the atmosphere will start to degrade the image.  I will test higher, but usually drop back.   Testing higher is very easy to do with the zoom.  A little more effort with the single FL eyepieces, but the single FL do give me a wider FOV for more drift time. 

Ed, a zoom combined with the helical focuser is a miserable experience in this scope. I have the scope and tried it. He needs lightweight, fixed focal length eyepieces.


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#19 SandyHouTex

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Posted Yesterday, 03:47 PM

If you want the best of the best, get this:

 

https://www.baader-p...ow-lens-2x.html

 

I have one and it is hands down the best barlow I've ever owned.



#20 aeajr

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Posted Yesterday, 03:50 PM

Ed, a zoom combined with the helical focuser is a miserable experience in this scope. I have the scope and tried it. He needs lightweight, fixed focal length eyepieces.

Ahh, I see.   I have used a zoom in a helical focuser without issue but perhaps it would be a problem in this one due to its small size. I would use an SVBony 7-21 or Celestron 8-24 in this one. They are smaller and lighter than the Baader.

 

I have put a helical focuser adapter into a Meade LX200 14" for fine focusing 1.25" eyepieces. I don't like the electronic focuser.  I simply used two hands when zooming. However, I guess it could be an issue for some.  I had not taken that into account. 

 

Well, depending on budget, I would recommend the AT Paradigm, the Explore Scientific 68 or 82 series.  I also hear good things about the APM 70 degree series.  I don't have experience with the Celestron X-Cel eyepieces that were mentioned earlier. 

 

 

ES82 vs. Meade82 vs. Celestron 82
https://www.cloudyni...nous-82/?hl=+vs


Discussion about Paradigm eyepieces
https://www.cloudyni...s/#entry8229760


Edited by aeajr, Yesterday, 04:05 PM.


#21 Dave Mitsky

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Posted Yesterday, 03:52 PM

If someone came up with a good zoom that could run from 2mm to 6mm, then that would be an option.

Well, there is the 3-6mm Nagler zoom eyepiece, which is very good but very expensive.  There was also a 2-4mm Nagler zoom but it's been discontinued. 

 

Of course, using a Nagler zoom might also be problematic with a helical focuser.



#22 rhetfield

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Posted Yesterday, 06:25 PM

In addition to the concerns over using a zoom in a helical focuser, I wonder if it really is a good idea to pair a heavy Barlow with a heavy zoom on the little scope. It is already problematic putting the Barlow together with the big 4.5mm.

DSO vs planetary - the scope is small and I am in a light polluted area. Most of the DSO work happens at the lower magnifications. Exit pupils are not going to let me look at anything much above the 144 I get off the 4.5mm. Most of the time I am using the 10mm or 25mm - sometimes with the Omni element on them. The planetary targets and doubles start with the 4.5mm and go up from there. Two totally different ranges with the little scope.

#23 rhetfield

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Posted Today, 09:35 AM

Brandon magic dankin 1.5x.

 

I have both the 1.5x and 1.25x and have been very pleased with them. 

That is starting to look more and more like a good way for me to go.



#24 aeajr

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Posted Today, 09:58 AM

I like screw on Barlows on my zooms but don't care for them on my fixed FL eyepieces.   I prefer a standard Barlow where you slip in the eyepieces.  That makes it quick and easy to change eyepieces within a magnification range.   

 

I have found having to screw and unscrew the Barlow from one eyepiece to another was bothersome when I have done it.

 

Just a procedural consideration. May not bother you.   

 

Length should not be an issue on a Newtonian, but if you are thinking of using this on a refractor, SCT or MCT, you may find that Barlow hits the mirror/prism.   I had that problem in one scope using the removeable element from the SVBony 2X Barlow. 



#25 vtornado

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Posted Today, 10:28 AM

There is a vintage Meade 140 2x 3 element barlow where it looks like the lens assembly

comes off.  Check it out.

 

 

I have an out of the box idea ...

 

Get a long tube classic barlow (2x)

I believe the barlow power is a function of the distance between the barlow lens and the eyepiece.

you can cut the classic tube barlow to the right size.

A pipe cutter may give you a nice clean cut (as opposed to a hack saw).

Some of the classic long tube barlows are highly regarded.

 

The GSO 3 element 2.5x barlow has a removable lens assembly.

However it cannot be screwed into an eyepiece.

The barrel may be cut down, and jb welded back the the body to reduce power.




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