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Finalised the scope, now some accessories help.

accessories dob
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#1 toofan

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Posted 19 August 2019 - 12:58 AM

Thanks everyone for your recommendations and inputs. 

I have decided on

1. 8inch Night Watch Dobsonian Telescope by GSO
D=203mm / F=1200mm Dobsonian F/6 - MADE IN TAIWAN Telescope

http://www.tejraj.co...-telescope.html

 

 

Please give your views in the following. 

Now looking for some accessories like a barlow lens

Seller is recommended me

2. GSO Super ACHROMATIC 2x BARLOW 1.25" OD, 2 ELEMENT LENS with T-thread

 

And I saw the following one which has 3 elements 

3. GSO 2.5x Barlow 3 Element 1.25"

 

Link below for both the above items. 

http://www.tejraj.co...low-lenses.html

 

4. Laser Collimator

Cheap one

 | 1.25IN Telescope Collimator 2INCH Adapter Reflector Telescope Newtonian SCA Laser Collimation 7 Brightness Level Astronomical. Rs 1350.00
https://s.click.alie....com/e/bU3YaCpS

 

Datyson

| Datyson 1.25 inch Upgarde Eyepiece Laser Collimator Alignment for Telescope with 2"adapter (without Battery). Rs 1800.00
https://s.click.alie....com/e/bQFOdcV2

 

 

Thanks

 


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#2 pregulla

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Posted 19 August 2019 - 03:29 AM

If buying cheap (datyson you linked is still a cheap one) collimator I would go with Cheshire, simpler design less of a chnace of it being out of collimation or having other problems. I have Datyson cheshire/sight tube combo tool that works well and cost me about $20.

 

What eyepieces do you already have? You may want to buy some first, before considering a barlow.

 

Also consider getting or building (search for denver chair) an observing chair. It really helps to improve observing experience.

 

Replacing straight through finder with RACI + RDF/Telrad makes it much easier and comfortable to star hop. 


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#3 aeajr

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Posted 19 August 2019 - 03:46 AM

Welcome to Cloudy Nights.  Congratulations on  your new telescope.  We are very happy to help in any way we can. 

 

Tips:

Top right of the screen you will see your screen name with a little down arrow.
Go to My Settings.  This is where you can make a number of changes.

You can set whether you want to receive private messages from people and how
you want to be notified about posts.


COUNTRY/REGION/STATE:  A good thing to do is to go into
your profile and enter your country and/or your city so people who are
trying to help you will know approximately where you are in the world. 



SIGNATURE:   Also, I recommend you create a signature (my settings)
where you can list your telescope your eyepieces or whatever you wish.  My
signature is at the bottom of this post.  A signature helps people help you
because they know what you have.  We get a lot of requests from people
saying, "I am new, what eyepieces should I get?"   Now we play 20 questions
to find out what telescope they have, what eyepieces they already own, etc..



BUDGET: When asking about things to buy it is good to provide a budget.   An
eyepiece can be $30 or it can be $300.  If we don't know your budget we
don't know how to advise you.  In fact, consider rephrasing your question
to, "I have $200 to spend on eyepieces, what would you recommend?”


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#4 aeajr

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Posted 19 August 2019 - 04:00 AM

Whether to get a 1.5X, 2X, 2.5X or 3X barlow is really a matter of how it fits into your eyepiece strategy.  I am assuming you only have the 25 mm and 9 mm Plossl eyepieces that came with the scope.  These are good eyepieces and will serve you well.

 

A 2X Barlow would be the best fit for these eyepieces, in my opinion.   This would provide you with 25, 12.5, 9 and 4.5 mm equivalents, all of which are within the capability of your telescope.   

 

The 2X GSO barlow you listed appears to be discontinued. The one below it (1470 + 18% GST) should be fine. 

 

A 2.5X Barlow would give you 10 mm equivalent which is too close to the 9.  And 3.6 mm equivalent which is too high a magnification under most conditions.

 

 

 

The collimation tools you listed appear to be the same unit under different labels. I believe I have that same unit under a different label.  This is a common practice in the astronomy market.    Mine works fine.  You do need to check it when you get it to be sure that the laser itself is properly aligned.  Mine was fine. 

 

These may be useful articles to help you with your new telescope.

 

Understanding and using a Barlow Lens
https://telescopicwatch.com/?s=barlow

 

Accessories to add to your Telescope
https://telescopicwa...ls-accessories/

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



How to Use a Telescope:  First Time User’s Guide
https://telescopicwa...ope-user-guide/

 


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#5 toofan

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Posted 19 August 2019 - 04:30 AM

What eyepieces do you already have? You may want to buy some first, before considering a barlow.

 

Also consider getting or building (search for denver chair) an observing chair. It really helps to improve observing experience.

 

Replacing straight through finder with RACI + RDF/Telrad makes it much easier and comfortable to star hop. 

Thanks. I will be having a 9mm and 25 mm eyepieces bundled with scope.

 

The chair thing is very interesting suggestion. And any upgrades will be due over time. I will be totally spend after this purchase. So will add things to the wishlist for Diwali Festival here in India. 


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#6 toofan

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Posted 19 August 2019 - 04:36 AM

Whether to get a 1.5X, 2X, 2.5X or 3X barlow is really a matter of how it fits into your eyepiece strategy.  I am assuming you only have the 25 mm and 9 mm Plossl eyepieces that came with the scope.  These are good eyepieces and will serve you well.

 

A 2X Barlow would be the best fit for these eyepieces, in my opinion.   This would provide you with 25, 12.5, 9 and 4.5 mm equivalents, all of which are within the capability of your telescope.   

 

The 2X GSO barlow you listed appears to be discontinued. The one below it (1470 + 18% GST) should be fine. 

 

A 2.5X Barlow would give you 10 mm equivalent which is too close to the 9.  And 3.6 mm equivalent which is too high a magnification under most conditions.

 

 

 

The collimation tools you listed appear to be the same unit under different labels. I believe I have that same unit under a different label.  This is a common practice in the astronomy market.    Mine works fine.  You do need to check it when you get it to be sure that the laser itself is properly aligned.  Mine was fine. 

 

These may be useful articles to help you with your new telescope.

 

Understanding and using a Barlow Lens
https://telescopicwatch.com/?s=barlow

 

Accessories to add to your Telescope
https://telescopicwa...ls-accessories/

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



How to Use a Telescope:  First Time User’s Guide
https://telescopicwa...ope-user-guide/

 

The 2x barlow I was referring was the one with added T adapter for attaching a Dslr to scope. The main reason for 2.5x was it's 3 element designe. I don't konw how will this work. But as suggested I will drop this Idea.

Is a laser collimator or Cheshire needed for collimation or it can be done some other way also. 

 

Thansk for the links. And info. 


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#7 Sky Muse

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Posted 19 August 2019 - 05:38 AM

I would urge you, if at all possible, to consider getting this one instead...

 

http://www.tejraj.co...-telescope.html

 

The extra features are well worth the extra cost.  It would be good to place the current outlay, the wherewithal, into just a telescope as it comes.  Extra eyepieces and accessories can be had later, and over time.  

 

For whichever kit you choose in the end, I would also recommend that you do not get a laser-collimator.  Get a Cheshire instead...

 

https://garyseronik....-what-you-dont/

 

https://galileoteles...collimator.html

 

If you feel you must get a laser-collimator, know that the laser-collimator must be checked and likely collimated BEFORE using it to collimate the Newtonian; else, mis-collimation can result...

 

https://www.youtube....h?v=bE09_X43UUQ

 

But with a Cheshire, you can collimate the entire optical system; you cannot with a laser.  If you use a laser, you can eyeball the rest that's needed for a spot-on collimation; or, you can make a collimation-cap out of the dust-cap of the focusser.  You drill a 2mm hole directly and precisely in the center of the cap, and line the underside of the cap with either the dull or shiny side of a circle cut from a sheet of aluminum foil...

 

collimation cap.jpg

 

Who knows, upon arrival the telescope may already be well-collimated, and from the factory.  The lower powers do not necessarily require an exacting collimation, but the higher powers do.

 

Collimation instructions... http://www.astro-bab...nian-reflector/

 

The telescope is capable of up to 400x, and then to see what very few people have ever seen.  That will require a spot-on collimation.  In the end, over time, you'll find it quite simple to accomplish.


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#8 SeattleScott

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Posted 19 August 2019 - 06:38 AM

Personally I have had good luck with cheap collimators. They are more straightforward to me than a Cheshire. There are some more advanced things you can do with a Cheshire but they are more complicated. Got a Cheshire many years ago but never used it.

Scott

#9 toofan

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Posted 19 August 2019 - 06:58 AM

@aeajr: thanks for those links once again. There is lots and lots of knowledge there. 


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#10 happylimpet

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Posted 19 August 2019 - 06:58 AM

A cheap laser collimator and a cheap barlow lens will (assuming the primary is centre spotted) allow perfect primary mirror collimation. Much easier than a cheshire.

 

The beauty of the barlowed laser method is it doesnt matter if the laser is a cheapo badly collimated one, it will still function perfectly.


Edited by happylimpet, 19 August 2019 - 06:59 AM.

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#11 kathyastro

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Posted 19 August 2019 - 07:19 AM

Accessories you need are an observing chair, preferably adjustable in height, and a red flashlight.  I find headlamps are convenient.

 

I recommend a laser collimator.  An inexpensive one is fine as long as it fits into your eyepiece holder snugly with no wiggle room.  You must test it to ensure that it is collimated itself, and adjust it if it isn't.  A laser is much easier to use than a cheshire.  The only adjustment a cheshire can do that a laser can't is the longitudinal position of the secondary mirror.  If you haven't disassembled the spider or the secondary holder, it doesn't need adjusting.  The laser will take care of adjusting all the angles.



#12 vtornado

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Posted 19 August 2019 - 07:39 AM

You cannot use your laser to align the secondary, but with your barlow you can use it to very accurately align your primary.

First make sure your collimator is collimated.  Which is easy to do.  There are articles on this site on how to do it.

Most nights 99/100, the secondary is fine, it is the primary which is just a wee bit off.

 

Then, Read this article.

http://www.smartavtweaks.com/RVBL.html

 

If your mirror is center spotted, it will take you 30 seconds to collimate your scope, and you can do it in the dark.

 

===

The GSO barlow is fine.  When selecting a barlow achromatic is fine, also look for one where the lens assembly

is threaded onto the end, With these you can thread onto an eyepiece and get 1.5x instead of 2.  A nice to have feature.

 

======

as KA mentioned, I do use a red beam flashlight every night.  It is good for finding lost parts in the grass,

reading printing on eyepieces, reading your chart if you use paper etc.

 

You many want ot consider a 32mm plsolls eyepiece to maximize your field of view.


Edited by vtornado, 19 August 2019 - 07:50 AM.


#13 Pogo007

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Posted 19 August 2019 - 07:41 AM

Re a barlow - you may want to choose one that has a removable cell which can be screwed directly into an eyepiece.  This, in effect, will give you two barlows (of different powers) in one.



#14 toofan

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Posted 19 August 2019 - 07:48 AM

I would urge you, if at all possible, to consider getting this one instead...

 

http://www.tejraj.co...-telescope.html

 

The extra features are well worth the extra cost.  It would be good to place the current outlay, the wherewithal, into just a telescope as it comes.  Extra eyepieces and accessories can be had later, and over time.  

 

For whichever kit you choose in the end, I would also recommend that you do not get a laser-collimator.  Get a Cheshire instead...

 

https://garyseronik....-what-you-dont/

 

https://galileoteles...collimator.html

 

If you feel you must get a laser-collimator, know that the laser-collimator must be checked and likely collimated BEFORE using it to collimate the Newtonian; else, mis-collimation can result...

 

https://www.youtube....h?v=bE09_X43UUQ

 

But with a Cheshire, you can collimate the entire optical system; you cannot with a laser.  If you use a laser, you can eyeball the rest that's needed for a spot-on collimation; or, you can make a collimation-cap out of the dust-cap of the focusser.  You drill a 2mm hole directly and precisely in the center of the cap, and line the underside of the cap with either the dull or shiny side of a circle cut from a sheet of aluminum foil...

 

attachicon.gif collimation cap.jpg

 

Who knows, upon arrival the telescope may already be well-collimated, and from the factory.  The lower powers do not necessarily require an exacting collimation, but the higher powers do.

 

Collimation instructions... http://www.astro-bab...nian-reflector/

 

The telescope is capable of up to 400x, and then to see what very few people have ever seen.  That will require a spot-on collimation.  In the end, over time, you'll find it quite simple to accomplish.

Thanks, I will try to re figure the budget. And can buy other things later. 

 

Personally I have had good luck with cheap collimators. They are more straightforward to me than a Cheshire. There are some more advanced things you can do with a Cheshire but they are more complicated. Got a Cheshire many years ago but never used it.

Scott

This is encouraging. 

 

A cheap laser collimator and a cheap barlow lens will (assuming the primary is centre spotted) allow perfect primary mirror collimation. Much easier than a cheshire.

 

The beauty of the barlowed laser method is it doesnt matter if the laser is a cheapo badly collimated one, it will still function perfectly.

Thanks for info. I don't know anything about this method. Will Google this method. 

 

Accessories you need are an observing chair, preferably adjustable in height, and a red flashlight.  I find headlamps are convenient.

 

I recommend a laser collimator.  An inexpensive one is fine as long as it fits into your eyepiece holder snugly with no wiggle room.  You must test it to ensure that it is collimated itself, and adjust it if it isn't.  A laser is much easier to use than a cheshire.  The only adjustment a cheshire can do that a laser can't is the longitudinal position of the secondary mirror.  If you haven't disassembled the spider or the secondary holder, it doesn't need adjusting.  The laser will take care of adjusting all the angles.

Its another expense but necessary also. For longer sessions comfort should be there. Let see if i find something here in India for this purpose. 



#15 aeajr

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Posted 19 August 2019 - 07:53 AM

In the accessories article I include the Denver chair.   I built this myself. Took about 2 hours and works great!

http://davetrott.com...observing-chair

http://www.schlatter...onomy/chair.htm

 

My first Dob, an Orion XT8i, came with a collimation cap which works great.   I later added one of those laser collimators and used the cap to check it.   I later added a combination sight tube/cheshire just because I wanted to learn to use it.  I used to then compare them all to see that they agreed.

 

How to Collimate an Orion Reflector Telescope using a collimation cap or a laser
https://www.youtube....h?v=YAVGcGEBmCE

 

 

A collimation cap, like this one, as shown in the video, does a great job. If you want to look into a laser later, this will get the job done.  A laser is easier to use in the dark, but the cap works well.  My friend collimates his Orion XX14 Truss Dob with a collimation cap.  Uses the flashlight feature of his phone so he can do it in the dark.

https://agenaastro.c...t-eyepiece.html

 

 

BTW, I own that GSO 2.5X barlow.  Works well in my smaller scopes but I can't bring it to focus in my 12" Apertura (GSO) Dob.  



#16 whizbang

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Posted 19 August 2019 - 09:01 AM

You are going to want a wide field eyepiece right away.  Get a 32mm Plossl. 



#17 aeajr

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Posted 19 August 2019 - 09:29 AM

You are going to want a wide field eyepiece right away.  Get a 32mm Plossl. 

I agree, but he has a 2" focuser so I would suggest he save up till he can afford a 2" wide view.  The GSO SuperView eyepiece, the Orion Q70 or the Agena Astro SWA are all good entry level 2" eyepieces.

http://www.tejraj.co...-eyepieces.html

 

This will be your finder eyepiece to complement your finder scope.   It will also be the eyepiece you go to for wide objects that look best at low power wide view. 

 

I would suggest the GSO SuperView 30 mm as the 42 mm might be too low power.  You might end up seeing the shadow of the secondary mirror.   In your scope this will give you 40X and 1.75 degree field of view.

 

When I bought my Apertura AD12 (Made by GSO), it came with a 30 mm GSO SuperView that was labeled Apertura. Certainly not a Tele Vue but it worked well enough. 

 

If I didn't already have 38 mm/70 degree and 20 mm/82 degree 2" eyepieces I would have kept it.  However, I didn't need it so it went with my XT8 when I sold it so the buyer would have a low power wide view eyepiece.

 

I have the Agena Astro SWA 38/70.  The Orion Q70 is the same eyepiece. Very happy with mine. I believe they are actually made by BST. 

https://agenaastro.c...a-eyepiece.html


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#18 NinePlanets

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Posted 19 August 2019 - 08:03 PM

Toofan, people have successfully collimated Newtonian telescopes since Isaac Newton without lasers.  Forget the laser collimator and save your funds for a good eyepiece instead. As Sky Muse pointed out, all you need to collimate your telescope is something to center your eye in the focuser. Cut the bottom off of an old plastic 35mm film can and cut a small (3mm) hole in the center of the cap and you will have all the collimator you will ever need for an F/6 system.

 

Here are a couple of collimators I made to save my film cans:

 

 

Attached Thumbnails

  • DSC07236_500.JPG


#19 aeajr

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Posted 19 August 2019 - 09:19 PM

Do you really think lots of people have 35 mm film cans just laying around?
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#20 toofan

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Posted 20 August 2019 - 02:25 AM

Thanks vtornado and pogo007 for the valuable inputs.

@aeajr: thanks for the links and detailed information. after the skymuse suggestion i am looking for the pro model of gso dob. Which will leave me with no cash at hand. But that model is offering a 2inch 30mm wide field super plossel and a 9mm 1.25" eyepiece.

http://www.tejraj.co...-telescope.html

But will soon be buying a barlow, a T ring and adapter.

 

I will be getting a collimation tool for free so hope that will do the job for now, the hard way.

 

Thanks to whizbang and nineplanets also. 



#21 aeajr

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Posted 20 August 2019 - 07:00 AM

Sounds like a good plan.  You will be very happy with that decision. 

 

I believe the Pro model is the 8" version of my 12" Apertura AD12 (GSO).   

 

In the USA we also find them under the Zhumell Z series (8, 10, 12) and the Orion Skyline (8, 10) labels, but it is the same scope.  Keep this in mind when you are discussing your scope with people on this forum.   We don't see the GSO labeled scopes in the USA all that often but people will recognize Zhumell Z and Orion Skyline.

 

Only significant difference between that one and what we get in the USA is that here they come with an 8X50 RACI finder, right angle correct image.  That one seems to have a straight through finder.   They both work.   

 

Many people like to add a red dot finder, RDF, or a Telrad as a second finder.  I use a red dot finder and the RACI on mine. 

 

You will enjoy yours!



#22 toofan

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Posted 20 August 2019 - 09:03 AM

Sounds like a good plan.  You will be very happy with that decision. 

 

I believe the Pro model is the 8" version of my 12" Apertura AD12 (GSO).   

 

In the USA we also find them under the Zhumell Z series (8, 10, 12) and the Orion Skyline (8, 10) labels, but it is the same scope.  Keep this in mind when you are discussing your scope with people on this forum.   We don't see the GSO labeled scopes in the USA all that often but people will recognize Zhumell Z and Orion Skyline.

 

Only significant difference between that one and what we get in the USA is that here they come with an 8X50 RACI finder, right angle correct image.  That one seems to have a straight through finder.   They both work.   

 

Many people like to add a red dot finder, RDF, or a Telrad as a second finder.  I use a red dot finder and the RACI on mine. 

 

You will enjoy yours!

Actually I don't know much about these Red Dot Finder /Telrad / RACI etc etc. As this is my first scope. I hope these words will soon be very familiar to me also. smile.gif

 

Few questions to you..

1. As you have similar model did a barlow is must to connect my dslr to it?.

2. Your Signature has quite a long list of gears. How good is 8-24mm celestron zoom. is it better then the single GSO eyepiece?

3. How good id Datyson barlow. Better then GSO?

Thanks.



#23 toofan

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Posted 20 August 2019 - 09:12 AM

Are zoom lens better then single pieces of same brand / class? If yes what would be the best choice but not that costly.? Also will they work well with barlow?


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#24 Sky Muse

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Posted 20 August 2019 - 03:40 PM

Are zoom lens better then single pieces of same brand / class? If yes what would be the best choice but not that costly.? Also will they work well with barlow?

Single eyepieces in dedicated focal-lengths are always going to be better performers over a zoom-ocular.  Barlows may be used with both, and effectively.  Zoom-oculars are for convenience.  They also serve as a teaching-tool, and in helping to decide at which powers you enjoy observing best, then to consider a dedicated focal-length for those powers.

 

An 8" Newtonian-Dobson, if collimated spot-on, is capable of up to 400x, and beyond, particularly when observing the Moon.  For everything else in the sky, others say that 200x to 250x will be the maximum, but never say never.  A 2x, and even a 3x barlow will allow you to experiment with that, and in ramping the power ever upwards, and to see what very few people have ever seen.  Else, you'll never know what you might've missed.  

 

I have a Meade zoom-ocular; same as the Celestron, same price-point, and here compared to a 32mm Plossl ...

 

Meade MZT8-24 - comparison2b.jpg

 

I got the Meade instead of the Celestron, as the Meade has more helpful markings on the barrel, and in being able to indicate at which power I'm actually observing.

 

I haven't used it much, yet, but I'm ever planning on giving it more sky time.  First impressions were that the views were not bad, not bad at all.  If the eyepiece is gently shaken, you'll hear the lenses rattle a little, but that's normal and no cause for concern.


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#25 aeajr

aeajr

    Voyager 1

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Posted 20 August 2019 - 07:56 PM

Are zoom lens better then single pieces of same brand / class? If yes what would be the best choice but not that costly.? Also will they work well with barlow?

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 in that range. Using an Orion XT8i as an example, if I include a 2X barlow for use with the zoom it will provide every magnification from 50X to 300X without gaps, my primary observing range.

 

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. 

 

I use the Baader Hyperion Zoom.  8-24 mm as my primary eyepiece in the midrange and I barlow it to often barlow 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 may barlow the zoom for the high range or go to single FL eyepieces.  I have a choice because I have both. 




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