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Help - First Scope Analysis Paralysis

Beginner Maksutov Mount Refractor Observing
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#51 Echolight

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Posted 16 June 2021 - 09:40 AM

For low power in an f7.5 scope, without buying a 31T5 Nagler, I'd highly recommend the Meade 28mm PWA at a fraction of the cost. 
 

It'll give you a nice wide view at 32x with a just right 3.73mm exit pupil.

 

Although for kids, a 68-70 degree eyepiece will be easier to look through. So maybe a 30 UFF or 35 Panoptic. Lifetime eyepieces.


Edited by Echolight, 16 June 2021 - 09:54 AM.

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#52 aeajr

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Posted 16 June 2021 - 11:18 AM

Eyepieces

 

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/

 

 

Your scope focal length will be about 900 mm My closest example would be my AT102ED at 714mm FL so your magnifications will be about 25% higher than mine and the field of view will likewise be about 25% less, but this can be used as an illustration.

 

Mostly I have standardized on ES and Meade 82 degree. My most used 1.25" eyepiece is my Baader Hyperion Zoom.  The Bolded ones are my most used eyepieces.

 

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

 

 

Astro Tech 102ED Refractor on manual ES Twilight 1 mount.  714 mm FL F7
Resolving power -  1.1 arc seconds

AA SWA 70   38 mm                  19X and    3.6 degrees  FOV   2”
Meade 82     20 mm                   36X  and  2.2  degrees            2” 

     
ES 82             14 mm                   51X and    1.6 degrees    
ES 82             8.8 mm                  81X and    1.0 degrees         
ES 82             6.7 mm                 107X and    .76 degrees         
Meade 82      5.5 mm                130X and    .6  degrees 
ES 82              4.7 mm               152X  and    .5  degrees
ES 82              6.7+2XB              214X and    .3  degrees
Meade 82      5.5+2XB               260X and    .18 degrees

 

Baader Hyperion 8-24  zoom       30X to   90X   1.6 to .5 degrees
Baader Hyperion 8-24+2XB       60X to 180X
Baader Hyperion 8-24+2.5B        75X to 225X

 

This is a set I built up over 3 years that is used in all of my scopes.  I also have a Celestron zoom that I tend to use in my smaller 1.25" eyepiece only scopes.  I have 1.5X, 2X and 2.5X Barlow Lenses. 

 

This is just for illustration.


Edited by aeajr, 16 June 2021 - 11:21 AM.

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#53 Mike49.285940

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Posted 16 June 2021 - 11:45 AM

So...what are you doing for eyepieces? whistling.gif

Hahaha, don't get me started! lol.gif I am going to work with the stock setup initially (comes with 20mm and 5mm 1.25" EPs), but I have already started looking into other options. As with OTAs and mounts, it seems there is a whole world of choices. The Baader Hyperion Mark IV zooms look like something worth having in the arsenal and I like the simplicity of a single EP - need to read up on it some more though. I also want some kind of Barlow (2-3X) to get high mag looks at solar system objects, which is where I plan to spend most of my time initially. I am also intrigued by a binoviewer set up, so will explore some options there but then have to factor in 2x EPs. Anyway, lots to think about as I am sure you are all well aware.



#54 BOSS3128

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Posted 16 June 2021 - 11:59 AM

Can recommend the baader zoom. If go that route, get zoom barlow as well.

The zoom pops up on the classifieds frequently. Would just need an ep for widefield then.
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#55 Mike49.285940

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Posted 16 June 2021 - 12:01 PM

Aeajr, that post is super helpful. You read my mind: I like the idea of pairing the Baader Hyperion zoom with a Barlow (2-3x). Have you tried that with a reducer (like a 0.5X) too? I imagine that would further expand the range for lower power / wider field so you could just have the zoom as a primary and swap barlows and reducers as desired. No idea if that makes sense or if there are other unintended consequences - need to read up on that.

 

To give you all a sense of how green I am with EPs, I still do not fully appreciate things like: (a) the distinctions between 2" and 1.25" EPs and what that means, practically, for the viewing experience, (b) how the degrees rating on an EP translates into what you see in the sky, and © how eye relief impacts the viewing experience and what my preferences are there (and more importantly, what my 5-year-old's preferences will be!). I know there are a ton of resources out there on all of this, so while I (im)patiently wait for my scope to arrive, I have a pile of reading waiting for me.



#56 aeajr

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Posted 16 June 2021 - 02:47 PM

Read the article on understanding eyepieces.  I wrote it for beginners so it should help.  Same for the article on Barlow lenses.

 

 

Never tried the BH Zoom with a reducer.  Can't think of any reason to do that, even if it would work.

 

As stated above  I recommend one or two low power wide view 2" eyepieces in the 65 to 82 degree range. These are your "finder" and large object eyepieces.  Normally I go to the zoom after that.  But having an option for wide view 1.25" is good too, so I built up the 82 degree set.

 

Initially I had the 38/70 and a 25/70.  Added a couple of 82 degree 1.25, then I got the zoom.   The zoom took over but I continued to build the 82s when they were on sale so that I always had the option to go to something wider if I felt the need.  The 25/70 was a cheapie so I sold it and got the Meade 2" 20 mm 82.  Like that one. 

 

Not listed in my signature, I also operate a 14" Meade LX200 at the Custer Observatory for outreach, FL 3550 mm.  There I typically pick a target and stay on it as I show it to the public and explain it, so the zoom really isn't needed.   I use the two 2" there.  I added the 14 mm 82 degree specifically for use in that scope.

 

I could give you the same chart for each of my telescopes.  It helps me to see if I have gaps.  I also use them when filing my observing reports so I know what eyepieces I used and anyone reading them can see what mags I used.

https://www.cloudyni...3#entry11113744

 

 

If you get the one or two 2" and the zoom with the 2.25X zoom Barlow that Baader offers, you have everything you need to get started.   If you want to build up your 1.25" set after that, do it over time as desire or opportunity presents itself. 

 

BH Zoom and Barlow or BH Zoom by itself and use a regular 1.25" Barlow

https://agenaastro.c...ow-2454827.html

https://www.eyepiece...on zoom&Submit=

 

In your scope the BHZ would give you 37.5 to 112X.    You will use it mostly in the 16 to 8 mm part of the range

 

With the 2.25X BH zoom Barlow you would have 84 to 253X.  That is about as high as you will go normally.   

 

If you want you can pick up a 3X to supplement that later if you find you can push higher on a regular basis.

 

I don't have the BH zoom Barlow.  I have 1.25"  2X and 2.5X.   I had a 3X but recently gave it away as I don't use it anymore.  My eyepiece set now covers a wide enough range that the 2X and 2.5X give me all I need on the occasions I need it.   

 

I also have a 2" 2X GSO Barlow that I really like.  I used it when I first got it but now it is in the spare eyepieces bin, dark and unused.   You don't need a 2" Barlow.



#57 Mike49.285940

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Posted 17 July 2021 - 11:12 PM

Hi all. I have been meaning to post an update on my journey into this hobby so here goes. I picked up the Sky-Watcher EvoStar 120ED with Stellarvue M2C Mount about a month ago after extensive deliberation. So far, I am really impressed. I have had razor sharp - by my untrained eyes - views of the Moon and countless stars, where conditions allowed, even though I have been viewing under Bortle 8-9 skies and indoors through a window (yes, I know this is not recommended, but it is somewhat of a necessity living in a condo building with a 5-year-old and bright skies until ~10pm). This was with the stock 25mm / 50° EP (36x). I have also had some great looks at Jupiter (+ Galilean moons), Saturn, Venus, and Mars. Looking forward to even better planetary viewing conditions in the months and years ahead. For stars and deep sky, I am picking up magnitude +9 with relative ease most nights.

 

High mag with the stock 5mm / 58° EP (180x) has not really worked - a bit too blurry to justify regular use. I am chalking that up to being indoors, conditions not being great (hot, humid weather and wildfires), and perhaps EP quality, though I cannot be sure of this last one.

 

A couple weeks ago I bought the Baader Hyperion Mark IV Zoom (24mm to 8mm) in the hopes of getting higher magnifications on the Moon and planets that are less blurry than the stock 5mm. That has worked to an extent. The Mark IV has provided a lot more versatility, particularly for solar system targets. I get reasonably sharp views between 24mm and 12mm. However, pushing beyond 12mm has not been great so far. A bit more blur than I would like, though seeing conditions have not been great either. Somewhat unexpectedly, I found the stock 25mm EP holds up quite well against the Mark IV at 24mm in terms of sharpness and contrast, and sometimes it even appears a bit better. I appreciate these are different focal lengths so not a true comparison. However, it has made me curious how the Mark IV compares to a traditional set of EPs in the same focal lengths. I imagine a set of TeleVue EPs would outperform the Mark IV, but hoping to attend some local astronomy group events to try those out and see how much different they are.

 

One thing that surprised me is how much I love the manual alt-az mount. It is allowing me to learn the sky in a way that I don’t think I would with a computerized mount. I knew I wanted to go this route for learning purposes, but I did not expect to actually enjoy star hopping as much as I do. There is something really exciting and rewarding about finding a “faint fuzzy” after hopping from a bright star (for me, typically Arcturus, Spica, or Antares) across dozens of other stars, all greatly aided by SkySafari. It is also a highly relaxing exercise and a great way to unwind after a long day. I recommend any beginners reading this who are on the fence to strongly consider a manual alt-az mount. I have nothing but good things to say about the M2C mount I purchased specifically.

 

Next steps include actually getting outside! We have a trip planned to a Bortle 2-3 location soon, but I also just want to get outside in my current location to compare the seeing to being indoors. I am sure it will be better, but I am curious how much better since I love the convenience of being at home. Waiting for darker skies earlier in the evening to make this more doable.

 

I also really want to push the limits of magnification. I want to see Jupiter’s cloud bands more clearly, Saturn’s Cassini division, and some Mars surface detail. I picked up a 3x TeleVue Barlow to have in the arsenal, should conditions allow. I am hopeful that under darker skies with good seeing and not being indoors, I will have some success. Although with Mars, I am resigned to the fact that I likely need to wait until next year (can’t fight celestial mechanics!).

 

Finally, I am starting to shop for a nice wide field EP, as has been recommended here, because I am really starting to appreciate field of view when star hopping. Learning EP specs has been a big part of this, but is also creating some confusion. For instance, with TeleVue, there are several options like 55mm Plossl (3.06° TFOV), 41mm and 35mm Panoptic (3.10° TFOV and 2.64° TFOV), and the 31mm Nagler (2.82° TFOV). While they are similar in terms of TFOV and magnification, the price varies significantly so not sure what I am missing that would justify the price differences. Any insights would be welcome.

 

All in all, really pleased that I finally pulled the trigger on a scope and got into this hobby. There is so much to see and learn. Thanks again to all the kind folks on this forum for sharing your experiences.

 

Clear skies!



#58 Dave Mitsky

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Posted 18 July 2021 - 01:14 AM

Finally, I am starting to shop for a nice wide field EP, as has been recommended here, because I am really starting to appreciate field of view when star hopping. Learning EP specs has been a big part of this, but is also creating some confusion. For instance, with TeleVue, there are several options like 55mm Plossl (3.06° TFOV), 41mm and 35mm Panoptic (3.10° TFOV and 2.64° TFOV), and the 31mm Nagler (2.82° TFOV). While they are similar in terms of TFOV and magnification, the price varies significantly so not sure what I am missing that would justify the price differences. Any insights would be welcome.

The difference is the larger and well-corrected apparent fields of view of the Panoptics and the Nagler T5.  Since you're refractor has a focal ratio of f/7.5, you may want to consider the 30mm APM UFF or the similar eyepieces now being sold by Celestron and Meade.  The 30mm APM UFF has garnered great reviews, is lighter than the Panoptics and the Nagler T5, and costs far less.




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