Mr niall

This is a really good one - really liked the context stuff about the plane of the milky way and how stuff is arranged around it, really adds something.

They're already doing it. Generally these things are tiny when they're launched and only visible for a few mins after reaching orbit anyway.

Either way, I don't think I've ever spent more than half an hour at the scope and not seen something zoom through the eyepiece. I think critical mass would have to be pretty high for it to become a real issue, there's plenty of junk up there already!

Calisto is easy - but the rest I'm in the same boat!

1 hour ago, John said:

Nice Skywatcher 12 inch for sale here (not my advert I ought to say):

https://www.astrobuysell.com/uk/propview.php?view=151231

 

That’s mine John - if you buy it from the classifieds here it’s even cheaper 😜

2 hours ago, pellgarlic2 said:

Ah, good suggestion - will check that out, thanks. 😃

And thanks for the link to that Cloudy Nights thread - great to see that people are getting on well with the AZ GTi, and able to squeeze so much out of it 🤩

You don't need tube rings as the diagonal on the Mak can be spun round to any position. What you would need is somewhere else to mount a finder. You could either drill holes for another finder base - or more easily pick up a Rigel Quikfinder or Telrad (telrad might be a bit overkill).

5 minutes ago, R26 oldtimer said:

Yes, I totally get your point. Even if it will need a recoat in the near future -god forbids- I will still get a brand new (optically) scope for half the price.

 

Now, now.... You've had your share of local bargains, It's my turn for a local listing that I won't have to pay my kidney for shipping.

Ha ha fair enough - but your find has the potential to eclipse anything I've seen in a while if its a good one. Even if you got it recoated it would still be less than I paid for mine. Worth considering...

I saw that one too. I only paid £360 for mine now come to think of it...

Yes... but a new 12" scope would be at least £800. It's all relative. And all I'm saying is if you needed it doing (and it sounds like you don't) - the best of the best is about £170. And then you'd not need any further maintenance for at least another two decades. 

Honestly I think that's the longest amount of time I've ever spent looking at a single astro picture. Brilliant!

3 minutes ago, haitch said:

Of course, another consideration when recoating is OO's Hilux coatings, whilst pricey, are rumoured to have a 25+ year life

 

They're not actually that pricey at all (all things considered); again about £160 to £170 for the whole package including stripping for a 12". You don't even have to remove it from the cell!

There's no definitive timescales. Generally if it looks fine; then it is fine. If it looks iffy then it is iffy. If you get one that is fine right now it could last 100 years. Conversely you could get one that is brand new right now and needs to be recoated in 10 years. It's difficult to say and depends on the conditions it lives in itself, but also luck to a certain extent.

If it were me I'd probably go for it. If it looks great now then chances are its been in a happy condition thus far.

edit: Just googled to make sure I wasn't imagining it, here's Gary's (sky and telescope) take:

While it’s true that the aluminized surface of a telescope mirror will deteriorate over time, there is no hard and fast rule about how long this will take. Some coatings last only a few years, while others will outlast you. Indeed, the coating on my very first reflector telescope looks absolutely perfect in spite of being more than 30 years old. When it comes to coating life, the main determinants are the environment in which the telescope is used and how it is stored. In both situations, preventing condensation of moisture from the air is a top priority.

So how will you know when your telescope’s mirror needs recoating? In short, if you have to ask the question, the answer is “not yet.” By the time the coating has deteriorated to the point where it actually affects the telescope’s performance, the mirror will look bad enough that you’ll have no doubt. Until then, the best advice is to stop worrying and enjoy the views.

— Gary Seronik

1 hour ago, Whistlin Bob said:

Thanks @Mr niall. Yes- I always feel a bit vulnerable leaving my gear outside- I was lucky this one was from my back garden! I was using large jpegs for this- 5184x3456- although some of that quality is lost as it encodes the video. It takes a little while to process but the computer seems to cope ok. Videopad has a curves feature as well, but each change seems to take about 5 minutes to apply as it rolls it out across the clip! 

So whats that, about 18MP each?! Oh no my poor computer couldn't cope with that!

very nice, saw those too but could only image them from the front of the house and I didn't fancy leaving my camera out there all evening?

What res photos do you use for your timelapses? Whenever I try and stitch mine together it crashes my computer, I'm wondering if the resolution is too high.

12 minutes ago, pellgarlic2 said:

It was my understanding that because a large aperture newtonian reflector is a good choice for DSO viewing, that it would therefore also be the best choice for photographing said DSO objects (as well as the Moon and planets). I imagine they can be used very successfully for that purpose, but with more expense than a lighter/smaller refractor of similar focal length?

Not really... I mean sort of technically they can but you wouldn't bother. You can get better results with much smaller scopes for a whole host of reasons (not least of all the cost of mounting something that size), and the results wouldn't be any better. The focal length is actually your enemy here, as it means a much narrower field of view that misses most of the wider nice stuff you'd want to photograph.

17 minutes ago, pellgarlic2 said:

which I've had attached to my SkyMax 102 a couple of times, with not very good results (just attempts at shots of the Moon, shots were always blurry - either poor focus, or vibration from the mirror), but it's clear now that I'd have to spend more to get satisfactory results from an astrophotography setup than I would for a purely visual setup.

Your Mak has a focal length of about 1.3metres which means, using the 500 rule, you can get photos of about 1/3 of a second before stars start to smear across the frame. However the moon is achievable; if you set the self timer to 10 secs then it gives everything a chance to settle down before it takes the shot.

11 minutes ago, pellgarlic2 said:

Thanks for the diagram - that makes it a lot clearer 😁

Regarding having not found the right scope, yeah - I am indeed embarking on further searching on the forums here and other websites regarding telescopes suited to/designed for astrophotography. 🤓

The 150i package has come very close to ticket all the boxes so far, but realising I wouldn't have the option to easily attach my DSLR has made me realise how important that actually is to me, and that I need to keep looking. It may be that I still end up going for that option if I can't find a better option though.

Ahhh… well if astrophotography is important to you I'd stop your search now.

There is no way you'll find what you are looking for at that price range if astrophotography is at all of any interest to you. Astrophotography gets exponentially more challenging and expensive for every mm of focal length you add. To achieve astrophotography worth doing with what you are looking at you'd would have to invest in at least a 150pds, HEQ5 mount, and guiding package. And software. You wouldn't get much change from £1500.

Astrophotography on its own is achievable with your budget but, assuming you already have a DSLR of some sort, you'd want to spend all of your budget on a skywatcher star adventurer mount and 100 or 200mm low f ration lens. Astrophotography is usually tackled with short focal length refractors too for simplicity and mounting considerations.

Visual and Astrophotography are very very different things.

as @Ricochet and @happy-kat say; this is where your focal point is:

So the focal length is around the same length as the tube usually, but this is just a coincidence! 

But, on another more sober note, if hacking a telescope to bits and voiding warranties is an action you are seriously contemplating to make this work... then you still may not have found the right scope... 

27 minutes ago, pellgarlic2 said:

I'm curious whether it would be possible to use the 150i OTA on the AZ GTi mount, as the AZ GTi and the Star Discovery are both listed as having "5 kg payload capacity"... But then I don't know if it's even possible to buy the 150i OTA separately.

I just need to figure out if the balance of capability versus ease-of-use of the Star Discovery 150i package is right for me (and relinquish the idea of being able to use the dinky little AZ GTi with a 6-inch reflector) .

I wouldn't. 

No the 150i isn't available separately. You'd be looking at the 150p (too heavy) 150pl (much too long and too heavy) or the 150pds (shorter but much too heavy). Also they star discovery has a fairly beefy steel tripod which is much better than the AZGTi tripod which isn't revered for its stability or sturdiness.

Seriously - seriously seriously - you ain't going to get a 6 inch scope on the AZGTi. It doesn't matter what the weight limit is it just wouldn't work, you'd be asking too much of the mount, its just not meant for that. The bundled packages are about the biggest you'd want to put on there. 

The 150i is the biggest scope I've ever seen mounted on a AZ goto like that, you wont find bigger I promise. The next step up is a flextube dob goto but they're about £800 I think.

1 hour ago, Paz said:

Regarding the ability to reduce the aperture of the ST80, doing this will also increase the focal ratio which will reduce aberrations. 

I've often wondered about that...

It wont really increase the focal ratio will it? I'm aware of the fact that focal ratio is a product of focal length divided by aperture. But similarly it is also true that the focal length is also a fixed number; determined purely by the objective lens. You can't turn an f5 mirror or lens into an f10 mirror or lens just by covering up a bit of the aperture? Its still an f5 lens surely? I mean if that were really true then the exit pupils would all change too.

Or maybe I'm wrong (that happens a lot too 🤔haha)

Hello there

Thought I would share my trolley building experience for those interested. The very important caveat to this is that there is nothing particularly innovative or complicated in this creation. This is particularly important as I am almost completely inept at anything related to DIY and am bound to fail. In fact, an excellent tag line for any company trying to bring a DIY product to market would be something along the lines of "so simple even Niall can do it". This is more a David and Goliath story about someone who beat very very short odds to create something really quite simple and easy to build despite a track record collapsing barbecues, doors that don't quite stay closed or reach the floor and fences that shudder and fly away at the slightest hint of a breeze. In 2010 my last minute recreation of the ISS using toilet roll tubes, tin foil, an empty cling film box and white emulsion actually attracted quite a lot of attention due to the fact it was unanimously agreed my 6 year old son had completely built it himself... Still an award is an award...

The other (in reality the biggest) consideration is cost - this whole thing cost me £18 to build using stuff I had lying around but even if you had none of it you could do it for less than £30. And it is 100% rock solid too which is a massive consideration when your telescope is your only "nice thing just for me".

The absolute easiest way to build this would have been to get a sheet of 18mm or thicker plywood and plonk wheels in the corners. But this was unattractive for two reasons; thick plywood is expensive £20-30 a sheet and - more importantly it still isn't really thick enough to provide a good anchor point for the wheels.

So I went with the classic "T" shape, with a scrap piece of wood I had lying around from a (failed) guinea pig house (they could get into the house but not out, long story). And I used the feet underneath as recessed mounting points so the dob wouldn't be inclined to slide off the trolley. This is attractive as it only requires one piece of wood and two 90 degree cuts (woo), even better is the fact that the 90 degree cuts dont have to be perfect; if you get them slightly wrong you can just wiggle the wood around until it seats and THEN mark out the final hole to cut for the third foot. If you look closely you'll notice my T shape isn't perfectly perpendicular cos this is what happened to me!

But importantly - no funny angle cutting required! As a man who has managed to cut himself so deeply he required stitches for the following - 1) trying to screw on a solar panel 2) Opening a tube of silicone sealant 3) Cutting a carrot; I am wisely not in possession of a cross-cut or table saw. Hand sawing only!

For info; A 2.4m 68x38mm batten from Wickes cost about £2.45 so that is considerably cheaper than thick ply. 

Wheels - I went with castors rather than pneumatic wheels, which I wouldn't have chosen ordinarily but did for the following reasons. 1) Despite actually having two 10" pneumatic tyres in my possession, I didn't have an axle. Getting hold of something suitable, and appropriate mountings, was going to be another £10 to £15 as I didn't have anything suitable in my armoury. 2) It would make it so wide that it wouldn't fit through my patio doors (which is a much bigger issue!). I easily managed to acquire a set of 4 125mm rubber wheeled castors (spend extra on rubber wheels it makes a huge difference to the noise and damping), 2 braked, 2 unbraked - for £15 including postage. I went for the biggest I could get as I have an 90mm lip to bump over to get the dob from the house to the patio. But you could save a fiver at least if you didn't need to go this big.

Construction - not much to say here; just held together with stuff I had in my armoury.  It occurred to me that the cross brace probably didn't need to be massively strong as most of the weight would be in the corners, but I did anyway; a single 100mm wood screw braced and wood-glued in place and then 4 angle brackets to prevent any side movement. I drilled 3 separate 32mm wide recessed holes for the dob feet to fit in, and a shallower one to clear the screw on the underside of the dob that secures the spinny base to the platform base. Into those recesses I glued a rubber disc from an old car mat - and then covered the top in some expanding PTFE from a previous failed project.  I took care to make sure that the depth of the holes was such that the dob base would compress the expanding ptfe tape but the feet would still sit at the bottom of the recesses.

The only snag was that the wood would have ideally been about 5mm wider due to the width of the castor feet but I made it work like a true Rockstar! Shockingly I didn't think to measure the width of the castor feet relative to the width of the wood before I started. But considering I once removed the entire Targa top of a car only to find out the replacement seals and mounting screws I had purchased were completely wrong and I had no way of re-attaching it despite the fact that rain was forecast that afternoon (and boy did it rain - the rest of that afternoon was like a bad episode of the A-team crossed with the blooper reel from Scrapheap challenge) - gives you an insight into the kind of "attention to detail" we're dealing with here.... Additionally the long piece over hangs slightly with an 18mm whole drilled through for attaching a handle / pull rope at a later date.

Couldn't really be simpler. But works nicely. The biggest unexpected bonuses are that the eyepiece sits at 1.7m at zenith now - which is fab as I'm 1.8m tall so its much more comfortable! Additionally the extra time and money spent on rubber feet, the rubber discs under the dob feet and the expanding ptfe strips means the whole thing is completely silent and there are almost no vibrations anywhere in travel, which makes nudging the big beast around even more of a pleasure, even at high magnifications.

So apologies for a long and frighteningly boring tale that, in essence, describes a man sticking two pieces of wood together; but honestly there are people out there like me who really don't have a clue when it comes to DIY and constantly fail despite our best intentions and desperately envy those of you who can do this stuff! Hopefully this may be of use to someone out there someday.

11 hours ago, pellgarlic2 said:

Ah, nuts. 🙄 I did think there might well be a reason that the largest scope it's bundled with is the Explorer 130...

So the "Star Discovery" Go-To mount seems to be a bit more capable when it comes to payload weight. Perhaps this could be the answer to my search - a 150 mm Newt on a Star Discovery mount at £375:

https://www.firstlightoptics.com/az-goto/sky-watcher-star-discovery-150i.html

Or I could get the mount and tripod separately for £285, and pick up the OTA of my choice if the 150i is no good... 🤨

Brilliant, I suggested that scope to you about 4 days ago 😉🤪

Like a circle in a circle, or a wheel within in a wheel, never ending or beginning, on an ever spinning reel haha.

What really helped me was writing down what I wanted from a scope, and what it needed to do for me, and what I didn't need it to do. 

I wouldn't put a standard 150 on a Star discovery mount. But the 150i is collimatable through the secondary. The primary is glued so it shouldn't need adjusting anyway as its set in the factory. The lack of tube rings and cell at the bottom keep it light. The views wouldn't be entry level....

The biggest issue with pushing the capacity of the mount is not so much the ability of a mount to work (in reality you can probably exceed the capacity of most mounts without damaging them in the short term) - but the real problem is that they become pretty much unusable through vibrations, wobbliness and lack of steadiness which can make the whole viewing experience a nightmare.

Also consider the length of the tube and the impact on the fulcrum if you've got something long - issues are expounded the further from the pivot point you get; which is why the heaviest bundled scope with the AZGTI is the 127 mak cos it's short. And even then it only tips the scales at about 3.5-3.6kg fully loaded

13 hours ago, pellgarlic2 said:

Thanks for the further helpful replies - I'm getting a really good sense of the options, and how they work for different purposes or viewing preferences.

I'm currently mulling over the following possibility - to go for the AZ GTi mount and tripod, and also get a standalone Explorer 150P, subject to finding confirmation of this OTA's weight. Best I can figure, it's the same as the "BK P15075" on Skywatcher's website, which lists the tube weight as 4.93 kg:

http://www.skywatcher.com/product/bk-p15075-eq3-wsteel-tripod/

That would put it right at the upper limit of the payload capacity of the AZ GTi... Has anyone used it with an OTA of this weight that can offer any observations? If it's feasible, that would allow me to use either the newt or my mak on the AZ GTi mount, which would be quite nice

No that wouldnt work, I used an opticstar ar90 on an AzGTI - it came in at 4.2kg with finder and eyepiece and experienced wobbly tracking at anything above about 80x mag. I wouldn't recommend putting a 150 on there. FLO actually recommended against putting a 130pds on one as it would be pushing it. 

29 minutes ago, pellgarlic2 said:

Ok, you've given me a lot more to think about, and I'm finding myself swinging back towards liking the idea of the Go-To setup  The reasons you give are very much in line with what I was thinking would be the benefits of such a setup.

However, that AZ GTi mount has a max weight rating of 5 kg, and 8-inch/200 mm newtonians seem to be nearly double that. So I'd need to look into a bigger mount, which would be more expensive. 😖

Your suggestion that "upsizing" the Mak would be significant conflicts with what "Mr niall" said a few posts back (it should be noted that I currently have a 102 mm, so moving up to a 127 would be less of an improvement than from a 90 mm scope).

It looks like my options (without sacrificing too much in any particular area) are either going to be:

1. Get a Go-To mount for my current scope, and maybe upgrade the OTA at some point in the future.
2. Upgrade my OTA just now, and try to patch up my existing tripod, and look into adding a Go-To device at some point in the future.

Well there's no "right answer" its all just opinion (that's the problem with astronomy!). But its important to keep in mind the type of observing that you are wanting to do. 

Me and @Cosmic Geoff are, I think, at very different ends of the spectrum when it comes to observing. As a purely casual observer I disagree wholeheartedly the statement:

29 minutes ago, pellgarlic2 said:

£400 price point you are still having to make severe compromises between cost and the size & quality of the scope and mount. 

I don't think that's true at all. If you wanted to spend 2 or 3 thousand pounds on a setup it would be considerably better. But that doesn't mean the price point you are shopping at will mean you will have to make compromises of any sort, you just have to be aware of the upper limits of what equipment at that price point can achieve. Which is a very different thing entirely. 

I wholeheartedly, 1 million percent, standby the assertion that, if you already own a 102 mak, then buying a 127 mak is not going to give you the "upscaled experience" you would hope for. 

Have you thought about, instead - getting the 127 Mak on the AZGTi? This is over budget, but you could probably sell the 102 here or anywhere similar and recoup the difference. This choice seems to satisfy most of the criteria you've listed. The danger of these things is trying to make your choice's "fit" around your current setup, sometimes its better to start again; and you already like Mak's so it wouldn't be a risk.

Conversely an 8" dob would be a very different choice BUT much cheaper, and quite big; but it's a great all rounder too (and you can image the planets with them its not that difficult), but there is a lot to be said for GOTO (although I don't use it, I prefer the thrill of finding stuff myself, sad but true)

I wouldn't make your choice based purely on spec, there's an emotional element to any purchase like this. You've got to get the one that "feels" right I would say, even more than getting the one that ticks all the right boxes. But £400 is a lot of money, and it'll get you some smashing equipment, you just wont get an 8" GOTO. 

There's been many debates about what those little caps are for haha.

There's a persistent theory that they're to aid with solar observing or for stepping down aperture's to cut through bad seeing but it's never been conclusively proved. It appears even skywatcher don't know! 

But yeah, as above, you'd want to use full aperture, solar film is sold in such quantities that there wouldn't be a cost saving either way.

If it were me I probably wouldn't go down that route - I haven't had a 102 but I have had the skymax 90 and skymax 127 and wouldn't say that there  was a massive difference between them, certainly not enough to justify having both. If it were me I'd jump straight to a 150mm scope like this:

https://www.firstlightoptics.com/az-goto/sky-watcher-star-discovery-150i.html

Or just get the AZGTI on its own

The 130 is much better at widefield viewing - something Maks  struggle with, but planetary and lunar performance is what makes the Mak stand out from the crowd; if that's your focus I'd either stick with your Mak and invest in the mount or make the jump to a much bigger aperture as above.

Just my thoughts.

edit - I use a dob; you may actually find the 200p more to your liking as it has a longer focal length (and is cheaper). Slewing around is dead easy but it doesn't have Goto like you wanted. Would be great on planets. Smaller people may need help getting to the eyepiece though.

1 hour ago, John said:

I've used the BST's in my F/5.3 12 inch dob and they work pretty well. F/5 is actually quite fast 

sorry yes of course - I meant its not a widefield scope despite it being fast.