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My First (Dobsonian) Telescope Maybe?


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Hello everyone,

I want to buy my first proper telescope. I've have watched videos on YouTube and read articles on various sites & forums. I'm getting a bit confused and have information overload. I thought this was going to be fun!

I have come to the conclusion that a Dobsonian will be the way to go. Ed Ting recommends the 8" Dobsonian as a starter and I can see why. I can afford to buy a 10" or at a push a 12" Dobsonian. The latter is where I'm leaning towards most likely (aperture fever already!).

I visited Rother Valley Optics, UK last week to look at telescopes in the flesh and to ask some questions. They had Sky-Watcher and also their own make RVO Horizon Dobsonians amongst lots of other scopes.

 

I can't find any reviews on the RVO Horizon series and wondered if anyone on here owns one or knows of someone who does?

The RVO Horizon had a fine tuner on the focuser (the Sky-Watcher didn't), is this a good thing?

Also is Ed Ting right about getting an 8" Dobsonian to start with?

Would you recommend another type of scope for a beginner?

Are there any other items I would be advised on starting off with like filters or Barlow lenses?

 

Thanks in advance for any help or advice.

 

Nigel

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Hi @nige745 and welcome to SGL. :hello2:

Plenty can be seen with the eight inch. Though everyone wants something bigger, there is of coarse the size and weight factor, especially if you want to take it and observe somewhere away from home.

With regard to filters then I would recommend a variable polarising filter, a #80A and/or a Baader Neodymium to begin with. Then later progress to UHC and Olll for deep sky.

Eyepieces are the most obvious things to upgrade and discuss from the cheap to the expensive. Everyone’s eyes and budgets are different. Avoid buying ‘complete’ eyepiece sets. Though I do not have any the BST Starguider range are very popular by some SGL’ers.

Another eyepiece discussion topic are zoom e/p’s. For lunar and planetary I have and use the TeleVue 3-6mm Nagler zoom and the Svbony 3-8mm SV215 zoom.

As for zoom e/p’s in the 8-24mm and/or 7-21mm… they are discussed/debated here on SGL and/or other amateur astronomy forums. I have a 7-21mm zoom e/p and is OK’ish.

In all honesty, a zoom eyepiece is not going to give the same view as a fixed focal length eyepiece. That said, the TeleVue and Svbony are an exception and I have no regrets buying either.

Edited by RT65CB-SWL
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Hello nige745 and welcome to the site. If you have seen them in the flesh and the size doesn't scare you then the 8" dob is a great way to start. The 200p dob was my first proper telescope and I was able to keep it in the outside shed so no real cool down required and a short carry distance. I wouldn't worry about a barlow but I would recommend a moon filter, they are very cost effective and it will stay with you. The next upgrade I took was a zoom eyepiece; not everybody's choice but it worked for me as you just change the zoom magnification rather than changing eyepieces. I wouldn't get one straight away, have a go with any eyepieces that come with the telescope first. Another thing that works well Is a mobile phone eyepiece adapter. I got my first picture of Venus with the 200p and the mobile at the eyepiece. All the best and let us know how you get on.

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Hello, I'm new to the forum and this is my first reply to a question as I may have a little insight. My first telescope recently was the StellaLyra 12" Dobsonian. I had Googled most options regarding 8" to 12" dobsonians. The Bresser having tube rings for possible mounting to equtorial mounts. Explore Scientific Ultra Light being compact. But I never saw any up close and personal. All online. Even now, having had the 12" StellaLyra for a few months, I've used it the once. Now this is the tricky bit. I'd go for the 12" again - it's 12". The dobsonian is visual and a basic imager. But such a light grabber. The 8" and 10" are both smaller and I've no experience of either but we know bigger is better. That's always on our minds. I'm pretty sure the StellaLyra 8" and 10" all use the same accessories and focusers but do check. I'm very happy with the StellaLyra 12". It's a life time purchase. So when it is used it's appreciated. Heavy and big. The swivel base is two parts. The base/feet, then a bearing, then the cupboard type upright. It comes apart with a small handled screw in the middle. That is the point of rotation. To move the telescope, I'll disassemble then base into those 3 parts. The main tube is carried as one piece. Heavy and awkward.

So in short, I wouldn't recommend a 12" dobsonian to anyone and wouldn't sell my 12" dobsonian ever.

But, the funny thing is. All 3 of those StellaLyra Dobsonians will introduce 2" eyepieces. It was this 12" dobsonian with a 2" 30mm eyepiece, if I remember correctly, that introduced me to Arcturus a month or two back. Yep, sorry, won't be getting rid of that 12" any time soon.

Good luck.

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@nige745

Can you navigate your way around the night sky or have the patience/willingness to learn? Do you live under relatively dark skies that suffer no major light pollution? If it's a 'No' to either you'll be stuck observing only the brightest few objects in the sky with your current shortlist.

If the above are a concern then add to your shortlist a Dob from the Celestron StarSense series. They are manual telescopes that work in conjunction with your mobile phone to tell you accurately (yes really) where to point your telescope. In overview, the phone app allows you to choose objects and then displays arrows where to point the telescope. The phone's camera then confirms if you are actually looking at the correct object. 

https://www.firstlightoptics.com/celestron-starsense-explorer-series.html?_gl=1*1ois7ar*_up*MQ..&gclid=Cj0KCQjwwuG1BhCnARIsAFWBUC29NXDH6oIyVRBvT6ZCN65FwUAY6KQxa3ejSqHZQKWZ2WaCU_KEV6saAuZmEALw_wcB

Some say these systems take the fun out of astronomy. Conversely many quit in frustration because the more exotic fainter stuff is too difficult to find. Be that due to lack of patience or the guide stars to navigate by are obliterated (to the human eye) by city light pollution.   

Edited by Jules Tohpipi
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@nige745 I have the Skywatcher 200P, 250PX and the 300PDS. The 200P is a doddle to carry around fully assembled, whereas the 250PX really wants splitting into base and OTA, although it is just manageable in one piece for very short distances. The 300PDS OTA is really a two person lift.

The RVO series are so new that there are no reviews, yet. However, they come out of the same factory as the Skywatcher, so don't let that put you off.

Edited by Mandy D
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One thing no one else has asked thus far is, what do you wish to observe?

And it has been touched upon, what is your observing location like (nearby sky glow, far off sky glow, immediate light sources nearby, what type of lights)?

Aperture is all well and good, but if you're surrounded by LP all you'll see is magnified sky glow with the odd very very faint smudge for DSO.

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1 hour ago, Elp said:

One thing no one else has asked thus far is, what do you wish to observe?

And it has been touched upon, what is your observing location like (nearby sky glow, far off sky glow, immediate light sources nearby, what type of lights)?

Aperture is all well and good, but if you're surrounded by LP all you'll see is magnified sky glow with the odd very very faint smudge for DSO.

These are good questions. I’m in a rather light polluted city - Bortle 7 - although I’m lucky in that our street lights are turned off after midnight. I have an 8” Dob and due to my local light pollution any more aperture is pointless. Well, pointless for DSO. The planets can occasionally take more aperture with light pollution. And an 8” Dob is easy to fit and transport in my car should I wish to visit a dark site. A bigger Dob might be an issue here.

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3 minutes ago, PeterStudz said:

Bortle 7

This is my issue also in bortle 7, I have an LED lamppost right next to my garden, surrounding area is all urban or industrial where they keep LEDs on all night. Even with my C6 a bright DSO target like Andromeda or M13 is a barely there smudge with next to zero definition, and they need averted vision to make even that out. Even with something more substantial I don't think I'd see any better.

Solar system is another story, detail and with my refractors incredibly sharp though outer and inner planets are mostly dots with a slight colour, Mars, Jupiter and Saturn are always good to look at, as is the moon up close but for me, I soon loose interest and want to see "the good stuff". Dark skies help tremendously (Bortle 4 or below, these areas are truly dark where you can see your moon shadow) but then portability becomes a consideration.

Also to the OP, temper your expectations, like a lot, rarely do you see visually what you see in pretty astro photos, my LP is one of the reasons I image more than view.

 

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I have both 8 and 10 inch Dobs.  There's not a huge difference on deep sky objects in Bortle 4/5 except on globular clusters, one of my favourite targets.  Here the difference is marked, with the 10 inch being clearly better.

The tube sizes are almost identical, so both fit on the back seat of a car.  If you transport your scope to a dark site you'll appreciate the 10 inch even more.

Despite being somewhat disabled I can take out both 8 inch and 10 inch sizes on my good days.  I can carry the tube and mount one in each hand with the 8 inch.  The 10 inch needs 2 journeys.

However mine are OOUK scopes that have aluminium tubes with large altitude rings.  The latter make the tubes much easier to carry.  The Bresser Dob tubes are similar but a little heavier.

The large altitude rings also make for a smoother mount. 

Additionally, the OOUK Dob mount is made of aluminium, meaning not only lighter weight but also a smaller footprint making it easier to carry as it's close to your body. 

In fact the 10 inch mount slips over my hips making it the perfect size.  I tried a 12 inch at a show last year and it was very definitely a step too far.

However, I found that I can manage 1 size larger with OOUK  and to a certain extent Bresser Dobs compared with other makes.

The OOUK scopes are expensive new, but mine are both used.  Having said that, I had to wait a long time to find a used 10 inch f/4.8.

If I had to buy new I'd get the 10 inch Bresser, simply because in head to head comparisons I did in shops it has a smoother mounting than other mass market Dobs.  This makes a definite difference, and in my opinion it makes sense to spend more on the mount in the first place as they're expensive to upgrade.  

 

 

Edited by Second Time Around
Added can manage 1 size larger with OOUK and Bresser Dobs.
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Wow!!

Thanks guys for all of the replies. I got stuck in the garden yesterday, repainting my shed and it took way longer than I expected, 8.30pm. 

I wasn't expecting this at all, thank you 💚

With regards to the size and weight. I intend to keep the telescope in the garage to start with and maybe it's own shed one day, so I won't have to move it too far to get into my garden. I also have an estate car so will be able to move the scope in that if needed. I am fairly sure that I would be able to manhandle a larger scope at the moment.

I had never heard of a zoom eye piece.

A mobile phone e/p would be helpful as I would love to take the odd pic. Astrophotography is a long way off for me at the moment (maybe one day?).

The StellaLyra 12" is one I have had a look at, amongst others. The RVO 12" OTA is 9kg lighter and the RVO base is 5kg lighter.

I can't navigate that well around the sky but I really want to be able to. I live in a Bortal Class 5 area. If I look Northwards, towards Sheffield, there's more light pollution. Southwards is noticeably darker. My garden is North facing but is long enough for me to be able to see over my house. I used to live in Sheffield and where I live now is markedly darker.

The RVO 12" OTA is 6kg lighter than the Sky-Watcher 12" and the base is 19kg lighter. Some reviews would be reassuring. If they come out of the same factory this is good.

The AstroHopper will be a big help. Got it on my phone now.

What would I like to observe? Good question and I don't really know the answer. The planets and moon to start with but they will maybe get boring after a while? I'd like to look at galaxies & nebulas, DSO's in general. Lots more DSO's to find out there.

OOUK scopes are out of my price league. I have looked up Bresser Dobs and found a post on here - Bresser or GSO for a 12" inch dob

This has only added to my confusion, STA 😁

 

 

More questions (sorry):

1. If the RVO Horizon 12" is lighter than other brands does this mean anything quality wise or is it engineered differently to save on weight?

2. Is a lighter base a good thing, would this make the base less stable?

3. If the scope is lighter will this mean the base will be able to move easier?

4. If I buy filters do I need to buy one for the different sizes of e/p: 2" & 1.25"?

5. Should I buy a collimator for the scope straight away? What type will be best?

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17 hours ago, nige745 said:

4. If I buy filters do I need to buy one for the different sizes of e/p: 2" & 1.25"?

5. Should I buy a collimator for the scope straight away? What type will be best?

4. I mainly use 1.25” as I only have one 2” e/p. You can get a 2”-1.25” reducer/step-down ring. Mine is similar to this one —>https://www.365astronomy.com/zwo-2-1.25-filter-adapter-with-m28.5-female-and-m48x0.75-male-thread

5. Some say the ‘Cheshire’ is the best method/option. You could always try a collimation cap as well or both. These are the cheapest options. If you do get a laser, then you may need to check and collimate it too… especially if it is the cheaper ones.

 

 

Edited by RT65CB-SWL
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1 hour ago, nige745 said:

I had never heard of a zoom eye piece

The zoom eyepiece covers a range of eyepieces, so instead of swapping eyepieces you rotate the zoom to the magnification you want. Whichever way you go with a telescope, you will soon realise just how fast everything moves, me being not the smoothest operating individual, I can't do anything quietly or quickly so the zoom suited me as it allowed me to keep the target in the eyepiece. I went for the baader zoom 8-24 and it is still my most used eyepiece.

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If I were to choose one, it would probably be 10". From 10" to 12" there is a big jump is size, from 8" to 10" - not so much. If you are considering 12" I would suggesting looking at one in person first.

RVO seems to have GSO 2 speed focuser, in my experience it is much nicer than SkyWatcher one. I don't use fine speed, but even the regular one is smoother and more accurate than Skywatcher. 

I prefer truss for 12" not much more in terms of set up time, DYI shroud isn't hard to make, but it is much easier to transport and store. I was able to fit 8" Skywatcher Flextube and 12" truss Meade light bridge into Skoda Fabia, together with observing chair and all other equipment. 

Filters are not a must at first. You can start without and add filters later if you want. With 2" focuser go for 2" filters. They can be used both with 2" and 1.25" eyepieces. If you put it on 2" to 1.25" adapter you can swap 1.25" eyepieces while leaving the filter. Also, the filters are most useful at larger exit pupils, so you'd want to be top use them with your lower power 2" eyepiece. 

You want something to be able to collimate your dob right away. I use cheshire for collimation. It is cheap, easy to use and reliable. 

Observing chair is another important item to consider. It improves the observing experience significantly. I am user Denver chair that I have build from some scrap wood.

To begin with eyepieces you can get a cheap zoom, something like Celestron 8-24mm or one of the Svbony options, and a 2x barlow. That should cover all your needs for first while and allow you to gain some experience before you decide where and how you want to expand your eyepiece collection.

RVO seems to come with RACI finder only. You want to add red dot or telrad/rigel to it, otherwise it will be a royal pain to use. For scope that doesn't come with RACI you may want to consider getting RACI+red dot.

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I'd disregard the quoted weights as these are notoriously inaccurate.  I'm almost 100% certain the RVO Horizon is basically exactly the same scope at exactly the same price as the Stella Lyra from FLO, both being made by GSO in Taiwan. 

These GSO Dobs are probably the best value on the market.  However, as said I prefer the slightly more expensive Bresser models, as do many on here who've tried them. 

Currently though the Bresser Dobs are available on eBay from the official UK importer at an even lower price than the better specification GSOs.

 

 

Edited by Second Time Around
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I have an 8" Bresser dob. I'm very happy with it and no regrets about choosing it over others (although the GSO ones weren't available then).

One thing about it, though. The finder that comes with it is awful, so  budget replacing it with a decent RACI (and RDF).

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I'd very much recommend a zoom eyepiece as your workhorse. One zoom eyepiece will cover multiple focal lengths and so is really excellent value for money.

Despite having high quality fixed focal length eyepieces, I use my zooms a lot more often. The zoom plus a Barlow lens and a low power, wide field eyepiece is often all I and others use the whole evening.

Fixed focal length eyepieces may be slightly better corrected when compared with a zoom at the same magnification. But that's not always a fair comparison as that magnification may not be the optimum for a given object. This is because one of the many advantages of a zoom is to be able to dial in precisely the best focal length. For instance, this may be 13mm or even 13.1mm, which may actually show more detail than shorter or longer fixed focal length eyepieces - even better quality ones.

I especially like the ability to increase the magnification to make use of brief moments of good seeing (a steady atmosphere). It takes more time to swap out an eyepiece, and the opportunity may then be missed. You can't see anything if you haven't got an eyepiece in the focuser!

They also make it easy to reacquire an object if it drifts out of the field of view by zooming out to a lower power. This is especially useful when showing objects to others.

Zooms also enable the field of view to be varied to frame an object to get the prettiest view. For this reason I particularly like them for clusters.

Many of those who post on forums advocating fixed focal lengths are experienced observers. It's so easy to forget what it was like as a beginner! A zoom eyepiece enables beginners to easily learn what difference a change of magnification makes on all the various classes of object. It also shows them what focal lengths would be most useful to their eyes, their telescope, and their observing conditions. They then have the option of buying/not buying the most appropriate fixed focal length eyepieces for them.

For these reasons I'd always recommend that beginners buy a zoom as their first eyepiece.

Edited by Second Time Around
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On 12/08/2024 at 13:23, M40 said:

The zoom eyepiece covers a range of eyepieces, so instead of swapping eyepieces you rotate the zoom to the magnification you want. Whichever way you go with a telescope, you will soon realise just how fast everything moves, me being not the smoothest operating individual, I can't do anything quietly or quickly so the zoom suited me as it allowed me to keep the target in the eyepiece. I went for the baader zoom 8-24 and it is still my most used eyepiece.

Everything moving fast is something I had not considered until you explained it.

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On 12/08/2024 at 14:55, pregulla said:

With 2" focuser go for 2" filters. They can be used both with 2" and 1.25" eyepieces. If you put it on 2" to 1.25" adapter you can swap 1.25" eyepieces while leaving the filter.

That is very helpful. I was thinking that I would need 2" & 1.25" filters.

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On 12/08/2024 at 14:55, pregulla said:

Also, the filters are most useful at larger exit pupils, so you'd want to be top use them with your lower power 2" eyepiece. 

I don't really understand this. Could you explain this again please?

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First, getting an 8" is a very safe bet. Even if you buy it new and sell it few months/years down the road, you won't lose more than about a 100$ on it. Buying it used, will in the end cost you zero as you sell it for the same money.

My first telescope 2 years ago was an 8" Sky-Watcher. I should've bought the GSO/Stellalyra as it is cheaper a bit and has a lot better accessories.

Few months ago, I upgraded to a GSO 12". It is better in each and every way but I would never have survived it as a first telescope. The 8" honed my skills both in observing and equipment so that by the time I got to the 12" I knew exactly what I was doing and am now able to optimize my experience and handle the extra weight / focal ratio well.

I wouldn't touch a Dobsonian without wheels on the base (you can mount them yourself) and carrying straps for the 12". Makes things so much easier with handling the 12 and even transporting with my car.

Check my channel below for the 8" review, the 12" comparison and some budget friendly equipment.

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On 12/08/2024 at 14:55, pregulla said:

You want something to be able to collimate your dob right away. I use cheshire for collimation. It is cheap, easy to use and reliable.

I have seen this explained on YouTube by 'Small Optics', I think it was him. If I were to use a laser collimator, I would need the laser collimator collimating! 😁

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On 12/08/2024 at 14:55, pregulla said:

Observing chair is another important item to consider.

Something else I didn't know existed!! Great shout as my legs are getting older by the day 😉

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On 12/08/2024 at 14:55, pregulla said:

RVO seems to come with RACI finder only. You want to add red dot or telrad/rigel to it, otherwise it will be a royal pain to use. For scope that doesn't come with RACI you may want to consider getting RACI+red dot.

Do these clip on to the finder?

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