Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_dslr_mirrorlesss_winners.thumb.jpg.9deb4a8db27e7485a7bb99d98667c94e.jpg

Recommended Posts

Hi,

As you can tell, I am new to the world of telescopes and astronomy. I have several questions about telescopes in general.

1) Some telescopes come with the ability to pinpoint stars and planets automatically with coordinates or some other technology. I'm wondering if it is possible to manually move those telescopes. I haven't been able to find the answer to this question anywhere, but I prefer one that is able to be manually moved over automatic movement if they are not able to move.

2) As far as I know, there are 4 types of telescopes: The Dobsonian, Refractor, Reflector, and Cassegrain telescopes. Which one is more advantageous to a beginner and which would be of use to a beginner for a longer period as they progress through their "stargazing journey?"

3) What are the advantages and disadvantages of the four aforementioned types of telescopes?

Thank you for reading and all help is much appreciated!

  • Like 1

Share this post


Link to post
Share on other sites

Welcome to SGL.

The GOTO scopes can be set to go to particular objects be they stars, galaxies, nebulae or planets. Celstron and Skywatcher bothhave these in different formats.

$ for $ the Dobsonians often give the best value for apeture and are well favoured on this site for good reasons. The Skywatcher dobs do have goto and those ones also allow a manual push to the object too.

Dobs are relectors, Cassegrain arereflectors too but they use a combination of mirrors to fold the light making the tube shorter, they are often known as SCT.

Refractors use lenses to focus the light to the eye piece, they tend to be more expensive size for size.

With any telescope the bigger the lens or mirror the greater the ability to grab light and see dimmer objects.

What sort of observing do you want to do, planetary, DSO? That will affetc the F ratio of the scope you choose.

But from seeing what folk post on here the 150-200mm Dobs seem to be good all rounders.

There will be other people on here all offering advice and ideas. This is just my 10 pence worth.

If you are near an astro club, go along and see what people are using, sometimes people find that a particular design of scope suits them better than others.

  • Like 1

Share this post


Link to post
Share on other sites

Welcome to SGL and congratulations on that first post.

Baggywrinkle has provided a great response and I agree with everything he says.

The only thing I would add is that reflectors (and SCT's to a lesser degree) require collimating fairly regularly and this is an extra consideration for someone new to the hobby.

Don't be alarmed...It is common practice and there are many posts on this forum to help you. I just think it should be considered in your choice.

HTH

Steve

Share this post


Link to post
Share on other sites

Welcome to SGL,

+1 for a 6" to 8" Dobsonian - cheap but high performance and can be easily upgraded to full tracking/searchinfg mode (GOTO).

Also it may be worthwhile visiting your local astronomy society to see and use different scopes........

  • Like 2

Share this post


Link to post
Share on other sites

There are actually three types of telescope. The refractor, the reflector and the catadioptric. The refractor uses lenses to focus the light. The reflector uses mirrors and the catadioptric uses a combination of both.

The dobsonian is merely a type of mounting. Most dobs are newtonian type reflectors. But not all.

There are a few sub types for each group, including achromatic and apochromatic for refractors. Reflectors are normally divided into newtonian and cassagrain types, and catadioptrics are sub divided into maksutov and Schmidt cassagrains.

There are other types but these are the main ones that are available commercially. That said, cassagrains tend to be pretty much extinct with very few commercially available these days.

What type of telescope you buy is often based on what type of observing you wish to concentrate on. Most beginners (quite rightly) wish to have a look at most things. For this a small 6"-8" Dob is perfect.

I believe some small Goto types have to be moved by motor only and manually moving them can damage them. Others can use both methods to find stuff. Best to check models individually.

I'd also recommend checking out your local AS to have a look at what's out there and how big stuff is.

Share this post


Link to post
Share on other sites

You need to consider what budget you are allowing for this as this will have a major bearing on what will be available.

Think about what you want to spend and what you want to achieve and then you will be able to get a more refined response on here.

Peter

Share this post


Link to post
Share on other sites

I think you need to consider the following, in no particular order:

- Budget, be aware there may be extra accessories that you will require

- What do you want to view the most

- Viewing or imaging

- Storage, these babies can get very big

- Where you will use it; home, remote sites

These all have an effect on your purchase and it is not just the telescope but maybe the choice of mount as well.

Having used binoculars for many years, when I made the decision to buy my first scope I took about two months to decide and went from Newtonian -> Dob -> my eventual purchase, a Mak. The fact that I have used it a lot and get a lot of enjoyment from it has proved I eventually chose what was best for me,... for now.

My advise is, take your time and do lots of research before buying. The old saying is; the best telescope is the one that gets used.

Share this post


Link to post
Share on other sites

You have started well, coming to the SGL forum. Welcome, there is a lot of information on this site and many experienced astronomers around to help you (unless the skies are clear, in which case we are outside). :smiley:

Share this post


Link to post
Share on other sites

Lots of good advice above.

I'd not rush to buy a telescope, it's so very easy to get something unsuitable for you.  Post # 5 mentions joining a local club, that's a very good idea. 

Question - do you like technology ?  Familiar with hi-tech stuff ?  Maybe a go-to is in your future, suits lots of people.

If technology drives you nuts, forget go-to and imaging, buy a basic Dobsonian for lo-tech visual, but you will have to learn the sky, manually track, that's what I love, but it's not for everyone.

Welcome to SGL - good move - Ed.

  • Like 1

Share this post


Link to post
Share on other sites

I like astronomy because it gets me away from people - so joining a club was never an option for me; and I do think that picking the "perfect" telescope using theoretical arguments can lead you down the wrong path compared to just buying something, living with the results, and selling it should it be unsuitable. Nonetheless, for what it's worth, bear in mind the following:

Telescopes are a compromise between opposing factors; for example (somewhat annoyingly) a 6" is slightly underpowered but an 8" is slightly overweight.

- and it's also worth remembering that the different types of telescope were not conceived for optical superiority over the refractor, but for pragmatism:

Compared to refractors:

- Reflectors are cheaper, but...

- Catadioptrics are smaller

So if we cast aside the thorny issue of budget for one moment, your primary concern should be the pragmatics:

1. Is this telescope going to live purely at home? If so...

  • Do I have to manhandle it into position?
  • How will I store it when not in use?

2. Is this telescope travelling with me? If so...

  • Is it just in the car? With family too? And luggage? More?
  • Might I want to take it on a plane? With family etc. too?
  • Will I know in advance if my destination is suitable?
    • Might I be forced to wander around in the dark (carrying a telescope & mount) looking for the ideal spot?

When it comes to telescopes, I say: "Plan on buying two - you will anyway!"

- and plan of buying two or more eyepieces as well - at around £40 each.

Good luck.

Share this post


Link to post
Share on other sites

1) yes the telescopes with motors and goto can still be moved manually, but then the point of tracking is lost.

2) the dobsonian is just a reflector which is mounted on a cheap but sturdy mount. One of its main advantages is that most of the money you pay for the scope goes into the optics, thus providing more aperture for the same amount. But the mount is such that you need to manually locate objects, and manually track them. Also it is not suitable for imaging. Cassegrain telescopes are such that they pack a larger focal length in a smaller tube.

Share this post


Link to post
Share on other sites

Skywatcher skyliner 150p £199 from this websites sponsor definitely not to heavy but then the 8inch one isn't,that much more but it,s being cumbersome that is the problem,you can move them in two parts though

Regards Jonn

Share this post


Link to post
Share on other sites

Skywatcher skyliner 150p £199 from this websites sponsor definitely not to heavy but then the 8inch one isn't,that much more but it,s being cumbersome that is the problem,you can move them in two parts though

Regards Jonn

If anyone asked me, "If you could only have one telescope, what would it be?" I think my answer would be the above.

(...oh, and I would also order it from First Light Optics too!)

Edited by great_bear
  • Like 1

Share this post


Link to post
Share on other sites

Thanks for the input everyone! I didn't expect this many replies!

I think I'm going to go with an 8" Dobsonian one! As far as my interest in using it goes, it'll mostly just be in my backyard and at night. Also, I was wondering whether or not I'll actually be able to use it in my backyard since they look like they go on top of a table. Would it be possible to mount them?

  • Like 2

Share this post


Link to post
Share on other sites

I was wondering whether or not I'll actually be able to use it in my backyard since they look like they go on top of a table. Would it be possible to mount them?

Just stick it on the ground buddy and use a chair to sit at the eyepiece.

Jobs a good un ;)

Share this post


Link to post
Share on other sites

Lol sounds like a good idea, but how big would a 8" Dobsonian be?

The regular 8" F6  (1200mm focal length) will usually have a tube about 45" long and 10" in diameter.

The size of the mount varies according to the make.  You can get some idea from online pics, but nothing beats seeing a scope in the flesh, so a visit to a retailer with a showroom, or maybe a local club that has a helpful member with an 8" Dob would give the best idea of size & weight. Most UK stores and clubs have friendly helpful people, probably the same in the US.

Saves a nasty shock when it gets delivered  :eek:  but most find an 8" Dob to be easily managed.

All the best in your choice, Ed.

Edited by NGC 1502

Share this post


Link to post
Share on other sites

Great info....I am very interested in the answers as well to help me decide on my upgrade scope (currently own the NexStar 4)! Want something with more power.

Share this post


Link to post
Share on other sites

The 200p is a great telescope and it provides great value for money! The 8" allows for some great views, and at the same time is not heavy also. One can easily handle the scope single-handedly!

  • Like 2

Share this post


Link to post
Share on other sites

Certainly avoid anything table top, it might be satisfactory for a while but if you really get into astronomy the shakey table will drive you nuts.

Another consideration is your terrain, a Dobsonion type is not best suited for uneven ground, whereas a tripod mount can be set for almost anything. My fav' location is a slope, I would need to put a brick under part of a dob stand to get anywhere near level.

Without which a dob would swing like an untethered boom due to gravity.

Share this post


Link to post
Share on other sites

Hi. Good luck with choosing your scope (lots of good advice above). There is one thing that might be worth reading on this site and use it as a reference when looking at scopes. There is a thread that is now a sticky called: 'What can I expect to See?' in the getting started with observing section. Think this will help set expectations as to what scopes are capable of, as well as remove the notion that you will see 'hubble-esqe' views. You can find it here

Regards

Share this post


Link to post
Share on other sites

Not wishing to be a wet blanket but be prepared to collimate the Dob on a regular basis - but it's not that difficult. When I had a 10" Dob I had to collimate it every time i used it but it was a Flex Tube.

Enjoy your scope.

Peter

Share this post


Link to post
Share on other sites

If for purely visual why not go for a 10",goldilocks of scope(not too big not too small easy to store and will give superb views) if finances allow

Just be mindfull that a 10" dob is quite a weight but can be separated into two sections making it easier to move

However if you want to do ap at a later date then the 8" is the one to go for.....good look with your choice

Share this post


Link to post
Share on other sites

Just stick it on the ground buddy and use a chair to sit at the eyepiece.

Jobs a good un ;)

Lol sounds like a good idea, but how big would a 8" Dobsonian be?

Plenty big enough to do that - they are pretty large. I have a 10", and I think that the 8" is the same length. The 10" is about 140cm tall when pointing straight up. 

I saved this diagram once upon a time. The Skywatcher dobs are similar sizes, I think:

post-28380-0-60625600-1403947113.jpg

I sit next to mine - I find it very comfortable for observing like that (I can't imagine having to stand all the time). I use a drummers stool - 'cos they're adjustable up and down.

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.