First telescope advice please

[NoClouds]

I’m totally new to astronomy and don’t even know if I’ll stick with it or not. So for my first telescope I want to spend just enough to be able to see objects of interest that could get me hooked. Alternatively, be able to sell if it’s not for me. To be honest, I’m not sure what will interest me, I’ve just had a notion for years to try it. Now that I’m retired, I’ve got the time. I live in the Ayrshire country side but have a fair bit of light pollution from surrounding towns, however I’m only 45 min from the Galloway Forest Dark Sky Park.

For a first telescope, I’m thinking of getting a Sky-Watcher Classic 200P Dobsonian for £369. According to the BBC SKY AT NIGHT MAGAZINE, I’ll be able to see the Crab Nebula, M81 and M82 in near-full Moonlight and under darker skies a clear-cut Cassini Division and a colour difference between the A and B rings of Saturn. I don’t think I want to spend another £200 for a 10” to start off with. I thought about second hand as eBay appears to have quite a few “unwanted presents” gathering dust but as the primary mirror is open to foreign object damage, I think I’d rather buy new.

If I get hooked, then I’d sell the SW and go for GSO’s StellaLyra 12" f/5 Dobsonian for £879. It appears to be a lot of quality bang for your bucks. Could also add an Asterion tracking or push to kit for ~£260.

Is what I’m thinking reasonable or flawed?

Also, what would be “essential” accessories for the SW 8” and would they be transferable to the StellaLyra 12"?

Many thanks in advance.

[Elp]

How patient are you?

[Emperor!Takahashi!]

I think that's an excellent plan. An 8" dob is a great instrument and value. Mainly, you'd just need a few good eyepieces to complement it. I suggest looking at the eyepieces forum for suggestions. The eyepieces that one would buy for an f/6 scope would mainly work well with an f/5 scope, and it's easy to make adjustments to an eyepiece collection later on.

Buying a used dob is also a great idea since they come up for sale often.

I say, "Go for it!"

Edited Sunday at 17:19 by Emperor!Takahashi!

[Gonariu]

Starting with a 200/1200 Dobson is fine. I saw that it comes with two eyepieces, a 25 mm (X48) and a 10 mm (X120) that are good for starting; for high resolution on the Moon, planets and double stars you could buy a third 6 mm eyepiece, orthoscopics are excellent eyepieces on the planetarium but there are those who prefer eyepieces with a wider apparent field on a Dobson. As for the transferability of the 8" accessories to the 12" there should be no problems, but it would be better here if you looked at the weight of the optics and the rockerbox which can be transported individually anyway; a 12" is certainly a divine optic! Keep in mind that a Dobson needs to be collimated every now and then.

[GTom]

The starting size for visual is great, 8" will show you quite a few deep sky objects and planets. However, the plain manual push-to Dobsonian is not easy to handle, most of your time will be spent on star hopping just to find your target. Even a non-naked eye planet search like Uranus or Neptune is a challenge manually. I'd recommend going Go-To, even if it means buying second hand gear. AFAIK the size you are after also comes in motorized goto edition.

Transferables: eyepieces, it is a good idea to get quality ones, also, if you age going for goto: your power source/battery.

 

Also, the 12" is considerably heavy, stick to the scope you can EASILY move!

Edited Sunday at 18:16 by GTom

[Bluemoonjim]

Seems like you've already researched this enough if you're thinking of a the StellaLyra 12" in the future. This may be controversial but I say go for the max 12" at the outset ... we only pass this way the once. What have you got to lose? 😊

[Emperor!Takahashi!]

2 minutes ago, Bluemoonjim said:

Seems like you've already researched this enough if you're thinking of a the StellaLyra 12" in the future. This may be controversial but I say go for the max 12" at the outset ... we only pass this way the once. What have you got to lose? 😊

I'd agree or disagree depending on whether the OP is pleased to set up the large scope regularly during the intial learning period. It's worth mentioning that a 12" dob is physically much larger than an 8" dob. The larger instrument can also take significantly longer to thermally acclimate. 

[Peter Turvey]

I started with a Skywatcher 130P table top Dobsonian during lockdown,  and have just 'traded up' to a  secondhand (2 year old, hardly used) Skywatcher Skyliner 250P Flextube GOTO Dobsonian (10") . I went for GOTO to reduce the amount  of time spent star hopping, and for the ability to track objects. 

A 300P (12") would have been nice but far too heavy for me to  move on my own!

So from my rather limited experience I would recommend a GOTO Dobsonian.  And second GTom's comments regarding getting quality eyepieces so you can transfer them to you next scope.  However you will end up wanting even better ones, so be warned!

[Bluemoonjim]

Your'e absolutely right Emperor. Over to the OP

[NoClouds]

Just been sorting dinner, didn't expect so many replies so quickly. Thank you.

Very patient.

I'm ok with the weights involved for the 12" and appreciate that the size of the tube makes the weight awkward.

34 minutes ago, Bluemoonjim said:

we only pass this way the once

Very true. Very tempted.

Taking on board the comments on goto's, I'm going to have a more indepth look at Asterion tracking/goto for both telescopes.

[Elp]

Regarding the magazine/online article about seeing objects, this is very much dependent on LP around you. I'm bortle 7 surrounded by LED LP immediately around the property, even with 6 inch aperture I can't see DSO objects with much more definition than a faint smudge, and that's using averted vision. Even something like M13 it's the same, however with a camera and 10s exposure it's there clear as day.

Having looked through a 6 inch dob from a dark sky site however (as in literally pitch black, no discernible clear LP even on the horizons) in a Bortle 4, I did see the whirlpool galaxy visually directly.

I asked about patience as you'll need a lot of it, without a goto or tracking mount finding objects can be challenging (and also part of the fun), it gets more testing the longer the focal length of the scope and the higher eyepiece power being used (it's why you tend to start with low power eyepieces first then work down once on target, or use an aligned finder to find targets).

I wouldn't dismiss binoculars to start with either, you'll get to learn the night sky. They do however benefit from a bino mount, there's nothing worse than vibrations/shaking, hence why dobs become recommended a lot for starting, or for good experience visual.

[Chandra]

It would be very hard to argue against that an 8" F/6 Dob is an excellent choice to start with... In fact, I would say that it is a great choice not only in the short term but even in the medium and long term: with that aperture you will be able to see much more than you mention, a lifetime is not enough for everything that a telescope like that can offer you. We tend to get carried away by the so-called "aperture fever", and although the OSG StellaLyra 12" must be (and certainly is) a wonderful telescope (https://stargazerslounge.com/topic/392187-stellalyra-12-dob-the-good-and-the-bad/), you should also consider its size and weight, and assess your availability to transport it to that dark sky area you talk about, since in reality where a large aperture makes a dramatic difference compared to a smaller one (as far as faint deep sky objects are concerned) is in those skies.

It should also be taken into account that the resolution difference in favour of the large aperture will be very limited (or directly "cancelled") most nights of the year by the quality of the seeing, whose poor or mediocre conditions affect the largest apertures to a greater extent (see the graph, valid for any value of the Fried parameter)... Apart from this, as has already been commented, a larger aperture, which supposes a much larger mass of optical glass, also requires a more prolonged cooling process, although this can be accelerated with ventilation.

This is not an argument to dissuade you from your possible future purchase project, but rather a note of aspects that I believe deserve to be considered before undertaking the investment in a large aperture, and while you "get hooked" (which will probably happen) on this beautiful hobby. On the other hand, it is evident that many of our colleagues have them, use them and enjoy them, and transfer their experiences to these forums (like the thread I have shared in this comment).

[Alan64]

I say go for a 10"...

It's the same length as a 6" and an 8", just a bit fatter is all.  Plossl eyepieces will play well with a 10" f/4.5 to 5, but if low-power, wide-field views are desired, eyepieces with more lenses and steeper curves may be required, and are more costly.  A coma-corrector may be necessary, depending upon the user's tastes.

Edited Monday at 00:12 by Alan64

[GTom]

I'd be very careful when advancing towards larger apertures, weight goes up quadratic with diameter. The Flextube 250 lists an OTA weight of 19kgs already, that might be somewhat disheartening when you realize it cleared out at midnight.

[Tiny Clanger]

1 hour ago, GTom said:

 that might be somewhat disheartening when you realize it cleared out at midnight.

I have stronger words to express the feelings when my 19kg OTA, 25kg base 250 dob, put out to cool for a couple of hours in anticipation of a good viewing session, has to be lugged back indoors unused due to un forecast 100% cloud cover ...

[Jules Tohpipi]

I'd say if you're interested in the Sky-Watcher 200p Dob then it's an excellent place to start. It's at a sweet spot for cost vs performance.

The views are certainly good enough to determine if the hobby will interest you or not. It's very quick and easy to set up at a moment's notice. They'll be no 'Can I be bothered with the faff of it all tonight?' anxiety. Plus, gives opportunity to see whether you're comfortable navigating and finding with a manual scope. Some struggle - either due to light pollution obscuring the guide stars or simply because it can be a disorientating experience.   

After spending a season with the 8" Dob you should come out knowing whether you: have a taste for the hobby; want something really big; require GOTO or StarSense navigation help; prefer looking at planets or DSO; and if it's DSO whether the views are satisfying enough visually or might prefer going down the EAA route for that.

 

 

[Second Time Around]

An 8 inch f/6 Dob is excellent value for money as it doesn't need expensive eyepieces nor the added expense of a coma corrector.  It's also relatively easy to carry around.

However, I don't think that the Skywatcher is the good value it used to be.

If you want to just dip your toe in the water I'd instead suggest looking at the Ursa Major from forum sponsor First Light Optics.  It's the same price as the Skywatcher, but has a better mount and arguably a better focuser.

In my experience one of the main reasons that beginners give up is that they can't find objects.  Yes, this can be solved with a Go-To scope that also adds tracking.  However, it both adds weight and considerable expense, and in my opinion it would be better to spend the money on a larger aperture scope in the first place.

Instead of Go-To I'd opt for push to as you've already mentioned.  However, rather than encoders (that I started with), I'd strongly recommend Celestron's Starsense Explorer system.  It's extremely quick and easy to set up, contains a vast database, and doesn't require re-allignment if you move your scope to avoid trees etc.

You could buy the Starsense Explorer 8 inch Dobsonian.  However, that's quite a bit of extra cost.  Instead I suggest you save some money and buy the Ursa Major Dob plus the least expensive scope in the Starsense Explorer range, the 70mm refractor. These combined will cost less than an 8 inch Starsense Explorer. 

That'll give you an extra ”grab 'n go" scope that will cool down very quickly when you're short of time. I'd add that nearly everyone buys a grab and go before long anyway!  It'll also have a much wider field of view.

You can quickly and easily transfer the Starsense Explorer unit between your scopes by getting a 3D printed adapter that fits into your finderscope shoe from one of our members.  I won't steal Ratlet's thunder but will get him to post a link.

One of the few downsides of the Skywatcher and Ursa Major Dobs is that they both come with straight through rather than right angle finders.  This isn't a problem with Starsense Explorer as the alignment is done during the daytime on terrestrial objects when arguably a straight through finder is better anyway.

Edited Monday at 20:58 by Second Time Around

[bosun21]

I have owned both the 8" and 12" Stella Lyra dobsonians and if I were you I would definitely start with the 8". They are a great telescope that will do everything that a beginner asks of it. It's easily moved around and transported if required. The 12" is considerably larger and I mean considerably! It's not a scope to transport in a car if you are going solo observing. Even with cary straps I needed help putting in a car safely. If you use the 8" for a season and find yourself hooked on the hobby then that's the time to consider something larger. I moved the 12" in and out of the house with a sack barrow as they are both heavy and awkward. I sold both of them and now have a 10" go to with which I'm very happy. It also needs the sack barrow due to the additional weight of the go to. Good luck with whatever you decide.

[NoClouds]

Again, thank you for all the comments.

clearoutside.com says I’m Bortle 4. Clouds on the western horizon do light up though.

I thought I might as well get the StellaLyra 8" as it comes with 3 eyepieces which appear to be a good starter set. Then the wife through a curve ball. “Why don’t you just get the StellaLyra 12”, you never buy anything for yourself” Which is true, I only tend to buy tools & things I need. She also wants to try star gazing.

I’m still happy to get an 8” but…. If we got the 12”, she would live in a dry out house which is probably only a few degrees warmer than external temps. I may even make an observatory for her, I’ve looked at what other people build for their dobs. It appears that there’s going to be 2 of us moving her now so I’m not bothered about weight, I’m still fit and fine lifting/carrying 25kg on my own. She’ll fit in the wifes car, Volvo XC70. The wife also suggested we could take the caravan to a dark site for a few days when conditions looked promising!

Is this what I would be looking at for coma correction on the 12” https://www.firstlightoptics.com/coma-correctors/stellalyra-2-4-element-photo-visual-coma-corrector-for-newtonian-telescopes.html

Goto - I was thinking about an inclinometer, degree circle & SkySafari but the Starsense option is brilliant, thank you.

Tracking – I’ll leave for just now.

Seriously considering the 12” now.

[Ratlet]

If you go down the 12" route, get yourself a sack barrow with a fold down toe.  It turns a monster dob into a drag and drop (not quite grab and go, but over short distances, it's quick as a flash to setup).  I have the 10" and it takes me about 3 minutes to setup.  I keep mine in a shed, under a tarp with a reusable dehumidifier bag.  This helps prevent condensation.

Not sure on others perspective but I wouldn't bother with the coma corrector at f5.  You'll not notice the impact being new (and also F5 doesn't really need it) and it will introduce a word of complications.

If you go down the Starsense route, I'd probably pick up the az80.  Apart from the mount it's not actually that bad a scope.  I designed this mount to transfer the Starsense unit to other scopes:

https://www.printables.com/model/559841-starsense-explorer-finder-shoe-mount-holder-for-vi

It works very well.  Either print it yourself or find someone to print it for you.  I do them at cost + postage (and 79p for chocolate biscuits) if you are in the UK.

If you go down the inclinometer and setting circle route you'll have fun.  I did that to start with.  It can get old quick, but it is pretty darn accurate.  I made a jig so I could point at a bright star and calibrate the inclinometer by adjusting the angle.  I'll try to dig out the link.  It's good fun but also a bit of work.

[Second Time Around]

The best size Dob will vary from person to person.  For me that's a 10 inch because it's the biggest I can carry as the steps and slopes in my garden preclude me from using a sack barrow.  Also bear in mind that you may want to move the scope during a session to avoid trees etc.

Rather than the Stella Lyra, that's a rebranded GSO, I'd recommend the Bresser.

You can (and probably will) upgrade many of the other components relatively cheaply, but not the mount.  So IMO the mount is the most important factor in deciding between the scopes. 

I did head to head comparisons and found that because of the large bearings the Bresser has a much better mount than the  GSO. 

I also found that with this style of mount I could carry one size bigger scope than the GSO and most other competitors by using the Bresser's altitude ring.

The Bresser also has a very good and better focuser, that can be upgraded at low cost to a dual speed.  Most retailers will do this for you free of charge before dispatch.

For the reasons I posted before,  I recommend that you buy the 70mm Starsense Explorer refractor as well.  I chose this model myself as the heavier 80mm is on the same mount and, especially with the longer tube, won't be as steady.  The 70mm will also have a wider field of view.

Be aware that Bresser and Explore Scientific scopes have a different finder shoe to most other makes.  This means that Ratlet's original Starsense Explorer adapter won't fit.

So a few weeks ago I bought a Bresser finder shoe to help the community and sent it to Ratlet.  He's now designed an adapter to fit Bresser/Explore Scientific scopes.

Edited 10 hours ago by Second Time Around

[Ratlet]

This is the basic design of the inclinometer adjuster I used.  It's not massively complicated.  Basically it just allows you to get it spot on once you very a star in your finder scope.

 

I can try and dig out some pictures of my dob to show how I set up the azi setting circle.  It's pretty easy and accurate.

Despite using Starsense I still have the setting circles setup on the scope and keep the inclinometer in my kit bag.

[PeterStudz]

If you want to easily find objects a cheap alternative is to simply strap a smartphone to the OTA and use an app. Here on my Dob at home and on a little grab-and-go out in Crete. 

For me it accurately locates targets via an in-app list every time. 

Whatever you choose good luck! 
 

Edited 10 hours ago by PeterStudz

[NoClouds]

Thanks for taking the time. 

I will go the Starsence route and will be in touch for a mount for it if that's ok. Thanks

Can I ask the importance of the 70mm having a wider field of view? I have a Slik camera tripod from the late 70's, very sturdy - any use to convert for the StarSense Explorer 70mm or larger?

The Bresser is a bit of a jump in price but interesting that you can easily change the mount type

Not decided on which dob to go with, a lot to think about.