Alan64

"...without costing too much...", would be just how much exactly?

For the last twenty years or less, we have been living in the heyday of inexpensive telescopes, and manufactured by a small handful of companies in China.

These companies have come a long way since their respective beginnings, and in producing above-average and even fine optics these days, of lenses and mirrors both, of refractors and Newtonians both.

With Newtonians, Newtonian-Dobsons("Dobsonians") in this case, you get a larger aperture over that of a refractor, per pound spent. 

With a refractor or a Newtonian, what you see is what you get.  If either has a long tube, it will have a long focal-length; if a short tube, a short focal-length.  

The lower powers are less demanding on a telescope, and are the forte of the shorter telescopes.  The lower powers also reveal the largest, the widest views of the night sky, and binocular-like.  Objects in the night sky are easier to find with those shorter.  Views at the higher powers are possible, to about 100x or so.   Hence, I would recommend a shorter example of either of the two designs, and for a balanced, well-rounded experience.

If you choose a Newtonian, there will be maintenance of the optical-system, collimation, to perform on occasion; like the fine-tuning of a stringed musical instrument.  The more often the "violin" is "played", a "bass-violin" even, the more often the tuning required.

If you choose a refractor, like a 90/660 achromat as previously suggested, there would be virtually no maintenance required.  Although the aperture would be smaller, again, per pound spent.  But under darker skies, a 90mm unobstructed aperture would show a great deal. 

With chairs, and a few tables of somewhat varying heights arrayed about and round the viewing area, a tabletop Newtonian-Dobson would serve; for example...

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-6-tabletop-dobsonian.html

There are the collapsible tabletop Newtonian-Dobsons, which are easier to put away upon the Sun rising...

https://www.firstlightoptics.com/dobsonians/skywatcher-heritage-130p-flextube.html

https://www.firstlightoptics.com/dobsonians/sky-watcher-heritage-150p-flextube-dobsonian-telescope.html

However,  I can't help but think about the mechanics of those, the pulling-apart and the collapsing, and how they might become damaged more easily over time; wonky in their motions.

A 130mm or 150mm aperture would be quite the eye-opening experience for your guests.

Then, for whichever you choose, a 7-21mm or 8-24mm zoom-ocular is an absolute must.

On 14/10/2021 at 19:51, wibblefish said:

@Alan64 perhaps I am using the wrong term here  I was purely thinking equivalent in terms of matching payload capability in this case 9kg unless I am completely missing something? Maybe I need to ask in the mounts section if anyone is using heavier OTAs on one and their experiences as I was surprised when I read about it and the skytee might be a more stable option as it can take 10kg loads.

From what I can see Bresser normally sell it bundled with an Exos-2 not sure what that translates into though it is an EQ class. I have also seen it with an Exos-1 option to which is a lighter weight mount so I am totally confused about mounts at this point! 

-- Edit I did indeed ask about the AZ5 and the 9kg capacity and got a good response that while possible not a good idea so back we go +2 for SGL ❤️

The Exos-2 is an EQ5-class equatorial mount.  The Exos-1 smacks of an EQ3-class, similar in appearance, but it's actually in between an EQ-2 and an EQ-3 in so far as load-capacity, an EQ-2.5 if you will. 

This is an EQ-1, on the left, which is the smallest equatorial mount on the planet...

On the right is a Bresser "Twilight Nano" alt-azimuth mount, an AZ1-class mount.  Both are supporting a 70mm f/12.9 achromat which is actually a bit too large for either one of those mounts.

This is an EQ-2, and a bit more supportive than an EQ-1...

Although that Meade 114/900 Newtonian is too large for it, as well.  But in both cases, that's how the industry pairs an entry-level mount and telescope together, and oft ill-fittingly.

My Celestron CG-4(EQ3-class) and Meade LX70(EQ5-class) mount-heads...

Incidentally, the Vixen Porta II alt-azimuth is in between an AZ2 and an AZ3, an AZ2.5 rather, but not the AZ3 of "renown" which is actually an AZ2-class alt-azimuth, and the alt-azimuthal equivalent to an EQ-2.

I do hope that that clears things up a bit.

Know that refractors differ from all other types of telescopes in different ways.  One of those is that a refractor requires a sturdier mount, per inch of aperture, over the rest.  You can cheat a little with a somewhat shorter tube, but in the end you cannot escape the inevitable. 

Then, nor can a sensible and serious refractor be placed onto, within, a Dobson alt-azimuth base.

13 minutes ago, Andrew_B said:

What kind of magnification were you using?

I found that at low magnifications diagonals were all pretty similar but it was as I got to higher powers that differences became readily apparent.

My bad; I have since edited my original post.  It was with an 80/480(f/6) achromat, and a Vixen 6mm "NPL" Plossl, at 80x.

My 70/300 is disassembled still, and before the diagonal had arrived.

I will be testing the diagonal further, and then decide if I want to keep it, or chuck it back to SVBONY.

Not surprisingly, my Celestron star-prism diagonal, the third contender, handily beat the two star-mirror diagonals.  Indeed, there was an almost 3D quality with the star-prism, which left the star-mirrors in the star-dust.

2 hours ago, wibblefish said:

I had a further chat with Alex at FLO (such good customer support!) and he confirmed that the SW AZ5 on a steel tripod can support 9kg which is the same as the EQ5. Definitely love the look of the Skytee 2 but it is expensive so having a cheaper option is better so basically will be between that and the EQ5 if I get the refractor or just get the Dob

Thanks for answering my EQ questions and discussions on mounts its nice to hear lots of opinions!

If we match the numerals, EQ-5 vs AZ5, the Sky-Watcher AZ5 is not actually the alt-azimuthal equivalent of an EQ-5; more like to that of an EQ-3 rather.

My own alt-azimuth, previously illustrated, is the alt-azimuthal equivalent of an EQ-4, but not quite to that of an EQ-5.  

The SkyTee-2 is fully the alt-azimuthal equivalent to an EQ-5, but not an EQ-6. 

The Chinese numeric codes for these mounts can be a bit perplexing, I'm afraid.

Then, this is the Bresser "Twilight I", and fully the alt-azimuthal equivalent of an EQ-3.  It seems to have been available at some point in the UK, but no longer.  I don't know if that has to do with the pandemic, or customs/marketing hiccoughs...

https://www.bresseruk.com/Astronomy/BRESSER-Twilight-I-telescope-mount-with-tripod.html

Now we come to this comparison, and from Australia...

That's the Saxon "Twilight I", same as the Bresser, and the Explore Scientific "Twilight I" sold in America I might add.  Note that the Saxon is described as an AZ5 as well.  But both of those are by no means alt-azimuthal equivalents of an EQ-5.  My own alt-azimuth is more supportive than both of those, and it's not the alt-azimuthal equivalent of an EQ-5 either.

It has been said, "Buy once, cry once".

I made certain many years ago that I was to have an alt-azimuth mount, large enough to support a wide range of telescopes, and up to a 150mm aperture in my case...

That mount is the same as this one, but my own came with a pier-extension and an integrated eyepiece-tray as options...

https://www.teleskop-express.de/shop/product_info.php/info/p1753_TS-Optics-Altazimuth-Mount-GSAZ-with-fine-adjustment-and-tripod.html

Said options are no longer available for that mount.

I'm of the belief that most should have at least one tripod-type alt-azimuth, one that will, again, support a wide range of telescopes, for you never know what you might acquire over the years, and decades.  I have over twelve telescopes myself.  In addition, it is imperative that the mount comes with slow-motion controls, as objects fly through the field-of-view of most eyepieces rather quickly.  Said controls allow you to "capture" an object, then to keep it in view for as long as you'd like.  This is especially important at the higher powers.

On the side, for more serious pursuits, you might then get an equatorial.

Granted, this does not take into account go-to mounts or excessive light-pollution.

Your telescope is at f/5(f/4.8, close enough), therefore use a 5mm(240x) eyepiece, or the equivalent with a barlow, for collimation/star-testing.

I finally got myself a 1.25" star dielectric-mirror diagonal...

https://www.amazon.co.uk/Dielectric-Diagonal-Reflectivity-Coatings-Compression/dp/B08QRY4V97/ref=sr_1_1?dchild=1&keywords=svbony+sv188p&qid=1634233841&s=electronics&sr=1-1

I've tried it out once thus far.  I pitted that one against this star-mirror diagonal, from an ES/Bresser kit, not a dielectric of course, and I did not notice any improvement whatsoever...

As a matter of fact, the ES diagonal was seemingly better than the SVBONY dielectric, but only by a slight margin.  But I will have to test them further in future, and before a definite conclusion.  I tested the diagonals with this 80mm f/6 achromat...

Therefore, at this point, I would not select a dielectric-mirror diagonal.  For now, select one with a standard mirror rather, for example...

https://www.amazon.co.uk/Diagonal-Adapter-Refracting-Telescope-Eyepiece/dp/B07GPMX7BN/ref=sr_1_22?dchild=1&keywords=astromania%2Bstar%2Bmirror%2Bdiagonal&qid=1634234686&sr=8-22&th=1

There are those cheaper, so consider those as well.

The Sky-Watcher "Heritage" 130P and 150P Dobson kits come with shorter, thereby ergonomic, f/5 Newtonians(reflectors).  All reflectors require maintenance, collimation, optical-alignment, often initially, and regularly thereafter on occasion.  One or both of the parents will need to learn and master the process...

https://garyseronik.com/a-beginners-guide-to-collimation/

Refractors, on the other hand, require virtually no maintenance, and are ready when you are...

https://www.firstlightoptics.com/evostar/sky-watcher-evostar-90-660-az-pronto.html

The refractor may also be used during the day, for birds in trees, ships at sea, that sort of thing; a Newtonian cannot.  But a child must supervised, during the day particularly, and to be taught to never point any telescope towards the Sun.

There is absolutely no rush whatsoever in picking out one's definitive refractor; the longer the wait, the better actually.  Play with the mirrors, first.

However, in the meantime, I feel that you, also, might work up to one?  A little taste of what might come...

https://www.firstlightoptics.com/evostar/sky-watcher-capricorn-70-eq1-refractor.html

...a 70mm f/12.9 achromat.

I have one of those myself.  I got it just this past summer...

Although, that kit is a combination from three others, one from early 1980s, 39 years ago...

We go about our daily lives seeing with our eyes, which employ lenses.  Then, there are lensing-galaxies in space, which act as refractors in revealing older objects behind them, and magnified...  

https://www.youtube.com/watch?v=51YYnaIWzsU

Are you not in the least bit curious as to what a refractor might offer?

Among refractors, a 102mm, or 4", is the "sweet spot" among the varying apertures of the design; not too large, nor too small, just right rather.  I had to work up to one myself.  At the age the 8 or 9, I got my very first telescope, a Sears(Towa) 60mm/2.4" f/11 achromat...

It needs restoring, as it is almost fifty years old.  It had also gone through a conflagration, yet survived.  I intend to keep it as original as possible, tripod and all.  It was through that telescope that I observed my very first object ever: Saturn, and with my late father who had first found the planet, and then called me out from the house to look.  Saturn was sharp, small, yet sharp as a tack, with an eerie fluorescent-green colouration, and likely due to the planet's lower position, somewhat above the horizon.

That was my only telescope until I was 27.  I then got a Parks Optical(Towa) 80mm/3.1" f/11...

That second was quite an upgrade from the first.

Eventually, I gave that one to a relation, and after its upgrade.  My first upgrade from that one was a Vixen 102mm/4" f/9.8 achromat...

But I returned that one after having it for only a few days.  I had simply and quickly decided that for my definitive 4" refractor, I wanted something else, something special.  That was in 2003, and the same year I acquired a 102mm/4" f/8 fluorite-apochromat...

I knew, even back then, that it would be most unlikely that I would ever get one larger than that, and for the rest of my life.  To this day, that still holds true, more than ever. 

Then, we have this, the modern incarnation of that one...

https://www.firstlightoptics.com/takahashi-fc-100-series-refractor-telescopes/tak_tfk10310.html

Well <tweaks dastardly moustache>, Celestron had treated the subject...

https://www.celestron.com/blogs/knowledgebase/i-accidentally-took-apart-my-celestron-20mm-erect-image-eyepiece-how-do-i-put-it-back-together

I don't like my own.  The view is too narrow for a 20mm, although you do get an erect, corrected image with the telescope.  Otherwise, it's hard as dried beans to find an alternative; shame, that.

Oh, don't set that 4mm(250x) aside, or throw it away.  I snapped this shot of the Moon through it and the 127mm telescope...

The live view was much sharper than that, and riveting!

I have a Celestron "PowerSeeker" 127EQ.  It also came with a 20mm erecting eyepiece, and both just like your own...

This is the order of the lenses...

At the bottom of the eyepiece, there resides the Amici erect-image prism...

Also, don't have any regrets whatsoever in having gotten that one, instead of the "Starbase" 9mm "orthoscopic", as the "Starbase" is not a traditional, tried-and-true, Abbe orthoscopic.

You don't want liquid seeping round and into the lenses.  I use a cotton-swab very lightly moistened with 91% isopropyl-alcohol.  You shake the swab after dampening it, or tap it against a hard edge of a table or other.  You can also press the tip into an absorbent towel or other.  Then, wipe the lens gently.  It won't harm the coatings.

I got this 80mm f/11 achromat, with an EQ2-class mount, all made in Japan, and for US$699 in 1992...

Today:  $1363

Nowadays, the kits are made in China, much less in outlay, and in many cases every bit as good, the OTAs in particular.

At this point, I don't think a 12" "Dob" is going to do it for you.  How about this rather...

https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-400p-flextube-dobsonian.html

3 hours ago, Ian McCallum said:

Do the StellaLyra or SW Dobs come into the former, rather than the latter?🤔

There are some qualitative aspects of Newtonians, therefore a bleeding over I admit, but in the end it's all about quantity rather.

There's simply no cure for aperture-fever, I'm afraid.

4 hours ago, Andrew_B said:

Tak's lenses have always been made by others (Canon-Optron since the 70s I believe) but they design their objectives and manufacture the lens cells in-house and their collaboration with Canon has been a very close one and not simply that of a buyer of components. They also grind and polish their own mirrors and for a company with fewer than 40 employees they do a surprising amount themselves.

Eyepiece manufacture has I think always been outsourced entirely although it would be interesting to know if Tak had any input into their design (I suspect not) or their specification (more likely).

It's not surprising that the mirrors are done in-house, as mirrors are easier to produce.  But then, we all know how superb Takahashi mirrors are, and to where one might wonder as to why not lenses as well, of crown and flint at least.

Filters for the planets are coloured...

The only one that I would suggest, and with reservations still, is the light-blue, #82A.  For example...

https://www.firstlightoptics.com/visual-oberving-rgb-filter-sets/astro-essentials-125-wratten-82a-light-blue-filter.html

The rest are only to look pretty, whilst simply standing over them arranged like that. 

24 minutes ago, chris0 said:

Im Based in Jersey Channel Islands UK.

I was only looking at filters as thats whats been mentioned if you want to see certain things stand out like jupiter, saturns rings etc

Im lost with a lot of that chart you put up, also i ve the kit with the eq mount but its not the best of  tripods as it does move on its own slightly

Now just working out what EP to go for!

The planets become quite interesting to view at 150x, and upwards of course.  The focal-length of your refractor, 1000mm, is used to determine which powers you want, and from this eyepiece and that...

1000mm ÷ 150x = 6.7mm eyepiece; that is, either a 6mm(167x) or 7mm(143x).

This is the diagonal that came with the kit...

The manufacturers often include that type of diagonal within entry-level kits for use during the day, and at night.  It is a correct-image diagonal.  But there are diagonals specifically for use during the day, like this 45° correct-image...

...for birds in trees, ships at sea, that sort of thing.  Then, there is a diagonal specifically for use at night, a star-diagonal; for example...

https://www.harrisontelescopes.co.uk/acatalog/celestron-star-diagonal.html

I have that same star-diagonal myself.  Here it is, on the right, and compared to our correct-image diagonals...

Note the apertures of the light-ports.  A star-diagonal will open that telescope up, and with a 32mm Plossl; for example...

https://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-sp-plossl-eyepieces.html

The 32mm would offer the widest view, and the lowest power(31x).  It would assist the finder, and in locating objects to observe.  Once you've located an object that you would like to see up close, you then insert a 12.5mm Plossl or a 12mm wide-angle type; for examples...

Again, and from this listing... https://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-sp-plossl-eyepieces.html (80x)

https://www.firstlightoptics.com/bst-starguider-eyepieces/bst-starguider-60-12mm-ed-eyepiece.html (83x)

With a 2x-barlow, a 12mm can be converted into a simulated 6mm(2x-167x); or a 4mm(3x-250x) even, if you insert the 2x-barlow into the telescope first, as described and illustrated previously.

A 2x-barlow, for example... https://www.rothervalleyoptics.co.uk/antares-x2-achromat-fmc-barlow-lens-125.html

You also have the option of a zoom-eyepiece...

https://www.ebay.co.uk/itm/SVBONY-8-24mm-1-25-Zoom-Eyepiece-Multi-Coated-Lens-Astronomy-Telescope-Parts-/283934574144

This is the chart again, and tailored specifically for your telescope; a 90mm f/11 achromat...

Your 90mm f/11 achromat sits at 3.11 on the scale, and lands on the first green block denoting the Sidgwick standard for colour-correction.  It simply means that when viewing brighter objects -- the Moon, the planets, the brighter stars -- you will see only a little false-colour, if any at all.

This is false-colour, and seen through my 80mm f/6 achromat...

Note the blue-violet rim of the Moon there.  That is because the 80mm f/6 achromat is physically shorter in length...

The perception of false-colour varies from individual to individual.  Where some see a bit of false-colour, others may see very little or none at all.  As we age, the perception of same diminishes.

14 minutes ago, Astro_Dad said:

How would you rate this one?

https://ensoptical.co.uk/index.php?route=product/product&product_id=10551&search=Circl

If in very good condition, get it.  It, too, albeit un-branded, has the exact same coatings as my UOs.

1 hour ago, Alan64 said:

I would think a toss-up between the two.  The UOs are more comfortable(ergonomics), and fully multi-coated possibly, whilst the Baader/Fujiyama are fully broadband-coated(optical-quality).  Still, you can't go wrong with either type.

18 minutes ago, John said:

The Circle-T "volcano top" orthos were produced under quite a lot of different brandings. University Optics is one of my favourites because of their colourful engraving but they all perform the same.

Sometimes I wish I'd held onto these:

That's an ideal line-up for higher-powered planetary use.

A 9mm is just barely a planetary.  Then, since a 12.5mm is so close to a 9mm, I've always gotten one of those as well.  I never wanted the 18mm or 25mm.

In addition, avoid eyepiece kits like the plague.  Instead, choose eyepieces carefully, one, or two at most, at a time.