Author Topic: Which telescope to choose?  (Read 108 times)

Chris Jiles

  • Active Astronomer
  • ***
  • Posts: 116
  • Activity:
    18%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #15 on: January 15, 2018, 02:29:48 PM »
BASIC ASTROPHOTOGRAPHY USING COMPACT CAMERAS AND SMART PHONES
Orionhttps://www.youtube....h?v=fz63FnLnswE

WEBCAM ASTROPHOTOGRAPHY - PLANETS
Introductory astrophotography using a Webcam for planetary imaging -https://www.youtube....vid=CeHj6qT5JSEhttp://www.universet...g-on-the-cheap/Video Astronomy – Reveloution Imager R2 – Ordered this onehttp://www.revolutionimager.com/

carmiphypart

  • Active Astronomer
  • ***
  • Posts: 105
  • Activity:
    7.33%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #16 on: January 16, 2018, 03:30:46 AM »
"Any feedback for me on this model..."

The Celestron SLT is a 5" f/5 Newtonian on a computerised go-to mount. The lion's share of the purchase price would go towards the convenience of a go-to, to find objects in the sky automatically, then begin to track them. As a result, the telescope that's included is going to take a back seat in so far as its overall quality(build and mirrors).

This member has observed through at least a few...

http://www.cloudynig...ease/?p=7595409

Of course, bad samples exist in all types of telescopes produced.

Most of the user-reviews do seem favourable...

https://www.google.c...slt 130 reviews

I would read through them before deciding.

Note that the SLT cannot be operated manually. You cannot point the telescope where you want with the hand, in other words.

planvelsynchcest

  • Active Astronomer
  • ***
  • Posts: 121
  • Activity:
    8.67%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #17 on: January 18, 2018, 01:40:32 AM »
In addition, this is the most popular of the SLT kits produced by Synta...

https://www.bhphotov...2,&Q=&A=details

Amazon also carries it... https://www.amazon.c...8&condition=new

The telescope, a Maksutov-Cassegrain, was originally designed and made for observing the Moon and planets, along with the vast majority of deep-space objects, albeit with a narrower field-of-view. The telescope itself would be easier to use and maintain, and is a bit better in overall build-quality compared to that of the 130SLT.

Francisco Hossain

  • Active Astronomer
  • ***
  • Posts: 118
  • Activity:
    15.33%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #18 on: January 18, 2018, 05:21:43 AM »
So the Maksutov-Cassegrain version, in your opinion, would be better for viewing and photographing the Moon?

Or would I be better off getting a larger aperture Dobsonian?

Zeek Letter

  • Active Astronomer
  • ***
  • Posts: 131
  • Activity:
    16.67%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #19 on: January 18, 2018, 07:32:34 AM »
If your focus is the moon and planets the Celstron 127 SLT Mak would be your better choice on that mount.

127 SLT, as mentioned by Sky Muse is on the same fullycomputerized mount. The scope will find the targets and will track them. Any OTA, Optical Tube Assembly,on that mount will track. Tracking becomes more important when you are talking about imaging in that the object stays within the frame. When using a camera phone, a web cam or a video cam, like the Revolution Imager R2, these pictures can be captured to a computer and stacked to give a similar effect to doing long exposure astrophotography, AP

You asked about a larger Dobsonian. Dobs come in many flavors and sizesjust like other scopes. Dobsonian refers to the mount. Most often you find it matched to a Newtonian Optical Tube Assembly, OTA.

An 8"/203 mm Dob gathers about 2.6X as much light as a 127 mm Mak. That means it can show you dimmer objects and bring out more detail in bright ones including the Moon and Planets.
I will use the Orion XT line to illustrate options. You have not provided a budget of any kind so I don't know if it these arein range.

The XT8 Classic is a manually operated 8" Dobsonian mounted Newtonian telescope - Very popular - $389
This is available up to 12"
http://www.telescope...uts?keyword=XT8The XT8i Intelliscope - this is what I have - Adds the Intelliscope feature and an upgraded finder scope system
Here you can use the computer assist or you can operate it manually, which I do about 50% of the time.
This is available up to 14"
http://www.telescope...ts?keyword=XT8i
Using the Intelliscope Computer Object Locatorhttp://s7d5.scene7.c...niversal_Video1The XT8G s a fully computerized, fully motorized 8" Dobsonian system - $1050
This is available up to 16"
Includes an upgraded focuser system. - This one finds the targets and tracks them or can be used manually.
http://www.telescope...ts?keyword=XT8G
Video overview
https://www.youtube....h?v=jFW_R6e-KlI
All three have the same optical tube assembly. The mount is the major change. All 3 are Dobsonian type mounts but one is manual, one is computer assisted and one is fully GoTo motorized

Antonio Zuniga

  • Active Astronomer
  • ***
  • Posts: 115
  • Activity:
    12%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #20 on: January 20, 2018, 06:24:07 PM »
Would it be possible to upgrade to the fully computerized, fully motorized mount at a later date? I would like to keep it under $800 with a $600 price tag being most comfortable right now.

twenuvtentu

  • Active Astronomer
  • ***
  • Posts: 123
  • Activity:
    10%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #21 on: January 22, 2018, 08:47:07 PM »
I have also seen some larger used telescopes in my price range. How do feel about used Dobsonian reflectors?

sremburjuni

  • Active Astronomer
  • ***
  • Posts: 110
  • Activity:
    7.33%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #22 on: January 23, 2018, 02:27:05 PM »
Quote
So the Maksutov-Cassegrain version, in your opinion, would be better for viewing and photographing the Moon?

Or would I be better off getting a larger aperture Dobsonian?

I would expect the optical quality to be better with the Maksutov, yes. Now, let's look at this...

A 5" f/5 Newtonian(130SLT) has a focal-length of 650mm.
A 5" f/12 Maksutov(127SLT): a 1500mm focal-length

Telescopes vary in their focal-lengths, but eyepieces are static; unchanging. Take a 1.25" 32mm 52° Plossl, like this one...

http://agenaastro.co...l-eyepiece.html (Incidentally, I'd get one when they're back in stock.)

The 32mm would realise a magnification of 20x with the 130SLT...

650mm ÷ 32mm = 20x

The same 32mm with the 127SLT: 47x, and the lowest power to be realised with the Maksutov...

1500mm ÷ 32mm = 47x

With the 130SLT and the 32mm Plossl, when looking into the eyepiece, you would see a view of the sky of about five full Moons wide, with the moons side by side. You would need a 2x barlow combined with a high-power eyepiece(7mm) in order to zoom in and see the Moon's features; the craters, mountains and valleys, and at about 200x.

With the 127SLT and the 32mm, you would see a view of about two full Moons wide. You could skip using a barlow with a Maksutov, and use a high-power eyepiece instead, like a 7mm or 8mm, and see the same, again, at about 200x.

Maksutovs are designed for moderate-to-high powers, and without the use of a barlow to achieve the higher magnifications.

A 5" f/5 Newtonian is designed for low-to-moderate powers without the use of a barlow; but with a barlow, the higher powers are also available.

EDIT: The 130SLT does comes with a 2" focusser, therefore a 2" 32mm 70° ocular will provide a view just shy of seven full Moons wide, and as the size of the Moon itself appears in the sky to the naked eye.

maulaepretag

  • Active Astronomer
  • ***
  • Posts: 129
  • Activity:
    17.33%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #23 on: January 23, 2018, 06:57:50 PM »
So it sounds like, if I were to go with this smaller motorized option, I should go with the 127SLT. It also sounds like I could control this from my laptop and take pictures from there with some sort of camera attached to the eyepiece.

Let me know if I am tracking properly so far.

cieledrore

  • Active Astronomer
  • ***
  • Posts: 129
  • Activity:
    18%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #24 on: January 25, 2018, 12:13:42 PM »
To answer your earlier question,I don't know of any of the Dob vendors that just sell just a separatemotorized Dobsonian mount for their OTA.

I have a lot of respect for Sky Muse's recommendations. I think that 127 Mak would be an excellent choice.

And as you expand beyond the Moon and Planets, that Mak can show you a lot of deep sky objects, DSOs. This is especially true if you are at a darker site.

specconcheckre

  • Active Astronomer
  • ***
  • Posts: 114
  • Activity:
    20%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #25 on: January 26, 2018, 12:21:38 AM »
Quote
I have also seen some larger used telescopes in my price range. How do feel about used Dobsonian reflectors?


You'd have to know what to look for: the age, the condition of the mirrors, etc.

This is the 8" Dobsonian of choice...

https://www.binocula...bZfoaAkbk8P8HAQ

It comes equipped with a 2" two-speed focusser, and a right-angle finderscope. The fine-speed control allows for quicker, easier and sharper focussing. The angled finderscope makes for more comfortable use. The Orion XT8 or Sky-Watcher does not have said features.

The mount is better, too, than that of the other two.

Roberto Betancourt

  • Active Astronomer
  • ***
  • Posts: 134
  • Activity:
    22.67%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #26 on: January 28, 2018, 10:58:15 PM »
In so far as a refractor for the Moon and planets, a longer-focus achromat would be in order...

https://www.bhphotov...2,&A=details&Q=

A refractor's lens assembly is unobstructed, unlike Newtonians and Maksutovs which have secondary obstructions, and shown here in that order...
As a result, the images through a long-focus refractor are sharper, more contrasty(blacker sky backgrounds and object details), but with a small amount of false colour seen when viewing some brighter and the brightest of bright objects.

The faster Celestron XLT 102 AZ, a 4" f/6.5, would exhibit considerable false colour when viewing all brighter objects in general.

A Maksutov is the only mirrored design that has been described as being "refractor-like", and with refractors, specifically the apochromats, being the standard by which all other designs are measured.


ruesonecrai

  • Active Astronomer
  • ***
  • Posts: 130
  • Activity:
    10.67%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #27 on: January 29, 2018, 10:19:37 PM »
Hard to beat a dob - 6" or even 8" models are very reasonably priced and show everything. Lifetime scope. With a RDF and Sky Safari or a good star atlas and have at it.
The Explore Scientific AR102 / Twilight 1 package is awesome deal.However this package below might do the trick for you and meet all your needs and budget ($579.99) -

Orion StarSeeker IV 150mm GoTo Reflector Telescope
http://www.telescope...pe/p/113917.uts

Good scope, nice accessories and the mount is pretty sweet. Key feature of the mount is dual encoders so it will track for you, find all those cool objects and you can also just scan about the sky freely and 'unplugged' with no need for the hand controller or power. Plus it is very photo and video friendly. You can also use the mount with various other scopes you may upgrade to in the future. A number of low cost good quality smaller refractors would work well on this mount and also give you a daytime scope.

Best of luck and clear skies to you and your wife.

Todd Treser

  • Active Astronomer
  • ***
  • Posts: 114
  • Activity:
    15.33%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #28 on: January 31, 2018, 04:46:02 AM »
Quote
So it sounds like, if I were to go with this smaller motorized option, I should go with the 127SLT. It also sounds like I could control this from my laptop and take pictures from there with some sort of camera attached to the eyepiece.

Let me know if I am tracking properly so far.

There are adaptors to hold a camera up to the eyepiece. I wouldn't use a large camera myself, like a DSLR. That's not to say you couldn't, as I don't own one, but I do know they're large.

"...sounds like I could control this..."

With the NexRemote telescope-control software, that should be a given. It's downloadable from Celestron's website...

http://www.celestron...onomy/nexremote

I suppose it's free.

Ralph Sonberg

  • Active Astronomer
  • ***
  • Posts: 119
  • Activity:
    15.33%
  • Reputation: +0/-0
    • View Profile
Re: Which telescope to choose?
« Reply #29 on: January 31, 2018, 05:57:19 AM »
Hi before you dismiss the 130 slt completely I would like to comment. I have this scope and it fully illuminates 2 inch eyepieces just fine I use a 31 luminos in it most of the time and it also works great with the 31 Nagler. I will admit it looks funny with those eyepieces in the focuser but they work great and the scope has no problem with them. Another point I have other bigger scopes but the 130 slt goes outside every time I set the scopes up. Good luck and enjoy whatever you get but the Celestron 130slt is a fine choice. Now back to your regular program.