Dob Dilemma. Doblemma.

[lawsio]

Hi all.

Bit of context for this query - I've been doing visual astronomy on and off for about 10-15 years, although during this time I've have had some years where I'm out at every opportunity and others when I've not had the scope out at all. Generally I've paid no attention to the equipment over the years and have just 'got on with it' but am now making efforts to update my kit a bit.  I've recently been adding to my options with the SkyMax127 GTi which I've had for a few weeks now, and am soon to have a ST102 on the way for some widefield observing, both of which are bought with travel in mind as much as anything else. 

My attention is now turning to my 'main' scope, my SkyLiner 200p (Or Classic 200p as its now called), and I have a bit of a quandary with it. I've had the scope for well over 10 years now, have moved house with it 3 times and in truth it's seen better days. I've been looking at taking it to Orion in stoke and making use of their servicing facility, and for about £150 plus a tank of petrol I can get it fully serviced and cleaned and for about £100 on top of that I could get it recoated if need be. This would, hopefully, get it back to something resembling 'as new' condition but I'm wondering if the money is better spent on upgrading to a bigger scope.

If I assumed, based on a bit of eBay research, that I have £100-£150 of resell value in the current scope, I could add that to the saving I'd make on not servicing it and maybe see that as £300 towards a new scope. FLO currently have the 250p solid tube and flextube options for around the £550 mark so I'd essentially be looking at adding £250 to current planned spend for an extra couple of inches of aperture and a brand spanking new scope with no spiders living in it. Is this worthwhile?

I know a general rule of thumb is to upgrade in 4 inch increments to see the biggest benefit but the 300p is near double the cost of the 250p so it's a much bigger ask. The difference in light gathering power between the 250 and 200 is bigger (About 56%) than between the 300 and 250 (44%) so I'm already making a big jump going from 8" to 10" but not sure if it's worthwhile if I'm not going al the way to 12".

Alternatively, if I kept the 8" but flocked it (Something Orion have said they can do for me whilst servicing) will the flocking give me better viewing than an unflocked 10"?

Thoughts welcome as always. 

Edited September 13, 2023 by lawsio

[Zermelo]

Without wishing to pry ... one factor you haven't mentioned is managing the weight and awkwardness of a larger scope.

I currently have a 6", and I know I will want to get a larger one at some point, but I doubt it will be a 12". I could manage it now, but I'm thinking ahead a few years, when it will become more of a struggle. Obviously some makes and designs are lighter than others of the same aperture, and an important consideration is whether a specific scope is easy to assemble/disassemble, so that you can transport it in easy parts. Some manage with larger scopes because they have a handy shed and need only trundle it a few metres to the observing spot. The same scope might not be feasible if it lived upstairs in the house.
And it probably won't be a binary decision - a scope might be manageable without causing hernias, yet just that little bit too much hassle for those evenings with a borederline weather forecast, so it might end up getting less use than it ought.

Flocking - yes, it can increase contrast and improve visibility of fainter objects. It's difficult to be definitive, because it depends on context, such as how dark the inside of the tube was beforehand, and how much stray light from neighbours you have to contend with.

[lawsio]

So the one that I've got is manageable weight wise (Ignoring the fact I tweaked my back moving it last time I had it out!), I don't have far to carry it from my garage to my patio so I'd probably be Ok with a bigger one, although I may end up having to moving the tube and the mount separately which I don't currently do. 

[bosun21]

If I were you I would sell your existing scope and buy either an 8” or 10” Stella Lyra dobsonian. They are better finished than the Skywatcher and comes with some great extras like a dual speed focuser, an 8x50 RACI, and cooling fan. I owned the 8” model before upgrading to the 12”. 4” doesn’t seem a lot but in the flesh the increase in size is very substantial. I use a sack barrow to wheel it to my observing site and it can be a struggle to mount it onto my EQ platform. I would try and see a 12” with your own eyes before making the commitment. Flocking can make a small increase in contrast but it’s nothing significant.

[Mandy D]

I can certainly notice a difference between my 200P and my 250PX. The latter gives me a noticeably brighter image and shorter exposure times on the Moon. I've never felt the desire to stop down with the 200P, but I recall being dazzled by the full Moon and deciding to use the 50 mm aperture in the cover to reduce brightness. In terms of handling these two scopes, I don't struggle measurably more with the 250PX and it takes up exactly the same floor space and height in my hallway as the 200P - the bases are both 520 mm in diameter.

The 300PDS is another thing altogether and it is honestly a struggle to carry it, but that is as much down to diameter as it is weight, which is 26 kg. The other downside with it is tube flexure, something I have never noticed on the smaller ones, but this beast is almost floppy. I am going to add two more tube rings to it and some long Losmandy dovetails in an attempt to stiffen it up. I don't notice the benefit of the larger mirror as far as light gathering goes, as I mostly use these telescopes at native FL and the 250PX and the 300PDS are of similar focal ratio, due to the longer FL of the latter.

Edited September 13, 2023 by Mandy D
Dang typos!

[Mr Spock]

Here's a 12" next to the shed it's kept in. That's as far as I can move it 

[Ricochet]

6 hours ago, lawsio said:

My attention is now turning to my 'main' scope, my SkyLiner 200p (Or Classic 200p as its now called), and I have a bit of a quandary with it. I've had the scope for well over 10 years now, have moved house with it 3 times and in truth it's seen better days. I've been looking at taking it to Orion in stoke and making use of their servicing facility, and for about £150 plus a tank of petrol I can get it fully serviced and cleaned and for about £100 on top of that I could get it recoated if need be. This would, hopefully, get it back to something resembling 'as new' condition but I'm wondering if the money is better spent on upgrading to a bigger scope.

What is actually wrong with the telescope that you need someone else to service it? If it is just a case of disassembling, cleaning, reassembling and collimating do you not think you could manage this yourself or do you think that the mirror(s) probably needs recoating and you want an expert to look at it?

With regards to saving the money and putting it towards a bigger scope I think you should consider why you have not observed during those periods when you have stopped getting the scope out. The bigger the scope, the more effort it requires to get out and the less likely you are to use it. If this has already been an issue with the 8” then it will probably be even more of an issue if you were to switch to an even bigger scope. However, now that you have two smaller scopes this effect should be lessened as any night you don’t feel up to getting out the 8/10/12” scope you might still observe with the smaller scope.

6 hours ago, lawsio said:

Alternatively, if I kept the 8" but flocked it (Something Orion have said they can do for me whilst servicing) will the flocking give me better viewing than an unflocked 10"?

Flocking makes a small difference but nowhere near jumping up a mirror size. The thing that made a much bigger difference to my scope was to mask the edge of the primary mirror, which made stars much tighter and reduced scatter across the field of view so the background sky is darker. FLO sell a Primary mirror mask for Skywatcher Newtonians. It states the 200PDS but I assume the mirror clip screw holes are standard across al Skywatcher scopes. Whatever upgrades you consider for the current 8” scope I would also recommend you apply to any new, larger scope.

[lawsio]

4 hours ago, bosun21 said:

If I were you I would sell your existing scope and buy either an 8” or 10” Stella Lyra dobsonian. They are better finished than the Skywatcher and comes with some great extras like a dual speed focuser, an 8x50 RACI, and cooling fan. I owned the 8” model before upgrading to the 12”. 4” doesn’t seem a lot but in the flesh the increase in size is very substantial. I use a sack barrow to wheel it to my observing site and it can be a struggle to mount it onto my EQ platform. I would try and see a 12” with your own eyes before making the commitment. Flocking can make a small increase in contrast but it’s nothing significant.

Thanks for this - that's an interesting call. I've had 4 or 5 Skywatchers over the years so that's always my go-to brand but maybe it is time to branch out. The SL ones look good to be fair and not too much more expensive.  

[lawsio]

2 hours ago, Mr Spock said:

Here's a 12" next to the shed it's kept in. That's as far as I can move it 

Yeah that looks like an absolute monster to be fair! Maybe I don't want to go past 10"!

[lawsio]

41 minutes ago, Ricochet said:

What is actually wrong with the telescope that you need someone else to service it? If it is just a case of disassembling, cleaning, reassembling and collimating do you not think you could manage this yourself or do you think that the mirror(s) probably needs recoating and you want an expert to look at it?

I'm not 100% sure on the coating, it's just that its part of the service that they check and advise on it. I probably could have a crack at it myself but I worry I might make it worse if I do 🤣 Bare in mind that its not something I'm looking at doing regularly, it's a once a decade thing if I do do it. 

 

45 minutes ago, Ricochet said:

With regards to saving the money and putting it towards a bigger scope I think you should consider why you have not observed during those periods when you have stopped getting the scope out.

Nothing to do with the scopes really, life gets in the way sometimes.  We've recently done some work to our garden which gives me more patio space so it's its a bit easier to do now. 

Also, the wife gets bored easily watching me squatting by a dob peering through a telrad so hopefully the StarTravel can keep her amused whilst I'm doing that and buy me some more outside time!

 

 

 

[Spile]

I updated/upgraded my Skywatcher 200P over a period of a couple of years and it was pretty straightforward. I now have the equivalent of the StellaLyra.

[lawsio]

So after a bit of research my number crunching has moved away from the financial side and more onto the weight side. I've watched the two really helpful size comparison videos that Ed Ting has done on YouTube, and have definitely ruled out a 12 inch. The 10 inch seems manageable, but is about 14kg heavier than the one I've got. Currently with the 200p I keep it on the base and lift it using the two handles that stick out the side, but on that StellaLyra one it looks like they're missing and replaced with much smaller tighteners (you can see the difference int he images below) I assume the idea with these is that you carry the base and OTA separately? One of the YouTube videos I watched suggested removing the OTA and storing it upside down on the base, is this a thing most people do?

[Second Time Around]

Also have a look at the Bresser Dobs.  These have large altitude rings that not only make for a smoother mount, but also make excellent handles.  In fact, because of this I found that I could handle 1 size up compared with Skywatcher or GSO Dobs (the Stellar Lyra is a rebadged GSO).

[Mr Spock]

2 hours ago, lawsio said:

One of the YouTube videos I watched suggested removing the OTA and storing it upside down on the base, is this a thing most people do?

I store my 12" on its mirror end. It's too heavy to turn upside down.

 

[Astronomist]

+1 for the bresser dobs. I have the 10" and it is great, the big altitude bearings do make good handles, especially if you wrap them in pipe lagging. Also it has a ridge around the base of the tube, which is handy for storage standing it on the mirror end. Generaly I just store mine on the mount though.

[Ratlet]

I use a sack barrow to move my 10" dob about.  I think I moved it in two parts about two times before I found it too much work and swapped to snack barrow.  Easier to move the whole unit with the barrow than either part on their own.

[bosun21]

I fitted longer rubber feet on the base of mine to allow me to stand it vertically on the mirror end if I so choose keeping the weight well off the collimation screws.

Like @Ratlet I also use a sack barrow to wheel it to and fro from my observing site. I then separate it in two to place it on my EQ platform. I also fitted two wrap around carrying straps which makes things easier. It’s not so much the weight of the 12” but rather it’s the sheer bulk of it.

[Matthew]

Hi Ben, another option worth considering is the 250p flextube from Skywatcher.I have seen them in the flesh and size wise they are very manageable and with the collapsing ota they don't take up too much space. I have owned the 300p and 400p and found them both very good scopes and there's always a couple for sale on the second hand market.

[Mr Spock]

Here's what mine rests on.

There are convenient holes to which they can be bolted.

[Mr Spock]

1 minute ago, Matthew said:

another option worth considering is the 250p flextube from Skywatcher

I had one of these for a while. You can pick them up with one hand.

[bosun21]

The SW 10” collapsible dobsonian tube weighs the same as my 12” SL solid tube dobsonian tube . Collapsed it will be easier to maneuver though.

[lawsio]

Thanks all. Regarding the flextube option, the thing that initially triggered this line of thought is FLO had a couple of the discontinued 250 flextubes with big discounts, although I think at least one of them has gone now.

I gather the flextube ones lose their columaation quite easily and add weight? I doubt I'll ever take it anywhere other than my patio so getting it in the car isn't the consideration. With that in mind is there a benefit to the flex tube?

[bosun21]

I’ve never owned a flex tube dobsonian. I was put off with them needing a shroud and I was also concerned about losing collimation. The later point is supposition on my part but not being any lighter swayed me away.

[Matthew]

From my own experience collimation was surprisingly close and only needed slight adjustment for a evening's observing after storage. For both scopes I did buy the astrozap  light shroud but when I first had the 300p I 'acquired' some packing foam from work (similar to camping mat foam just a bit wider) and lashed it on with some black insulation tape. The one advantage I found the flextube had over solid tube Newtonians was how easy it was to flock.  

[Ricochet]

17 hours ago, Astronomist said:

the big altitude bearings do make good handles, especially if you wrap them in pipe lagging.

👍 I wrapped handlebar tape around mine