Upgrading to a bigger scope - Advice needed

[stargazerlily]

Hi everyone,

Now that I'm getting into this astro-photography lark I'm thinking about upgrading to a bigger and better scope. I currently have a SW 150PL which is pretty good but I would like to go bigger.

For bigger read better and clearer planetary images then I can get from my 150PL.

My main interest at the moment is moon and planetary imaging with a web cam. I'd like to continue down this road for a while although I do have a Nikon D40 but not used it yet for imaging. I'm also interested in observing but not got into DSO yet.

So ... I'm looking for a scope that best fits my current imaging interests but could also double as a good observing scope. My budget is about £350-ish. After trawling various threads on this forum I've focused (excuse the pun) on the SW Skyliner 200P Dob.

i) Would this scope suit my 'imaging' bill? Are there any variations to the 200P that might be better.

ii) Does this Dob mount have any way of auto-tracking an object (e.g. like the RA motor on my SW150)?

iii) I'm assuming I can just slip in a web cam into the focus tube like with my SW150.

Many thanks for your advice

Pete

[stargazerlily]

Done a bit more surfing ... I now have two scopes in the frame and I was wondering what people think about either scope. The two are:

SW 200P on EQ5 mount (+ separate dual axis motor drives) ... or

SW Skyliner flexi-tube 200PX Dob with built in motors

I did read some where that the flexi-tube would need collomating on a more regular basis compared to the SW 200P.

Thanks

Pete

[Rossco72]

The flextube design needs collimating every time you use it (or at least a check) as it is very dependant on the struts being exactly the same each time.

A dob is ok for webcam but not really an imaging platform as such, the tracking is Alt-Az and field rotation does occur.

It is always difficult to answer these queries as the accepted (percieved?) wisom is that you need at least an HEQ5Pro type mount to start imaging with. This can be relaxed a little if you are only looking at Webcam work as the exposures / limits / quality is generally reduced.

Your current scope is more than capable of great images, I would focus more on a good mount for it.

[sixela]

Especially if you're doing planetary imaging, you really need to collimate them both before every session.

The GoTo version of the Flexitube Dob is not too bad - the Auto version has a mount that's a lot more fickle. Apart from that, the Dob mount is actually a lot more stable than a 200mm Newt on an EQ5 (that scope really wants at least an HEQ5 even for planetary imaging), but of course unsuable (like all Alt-Az mounts) for DSO photography.

Those two are very, very different in almost all respects.

Visually, I'd rather have the Dob but that's very personal; if you have an EQ mount you can reuse it for a small refractor and DSO photography (although if you want that scope for DSO photography you'd better get an EQ6, but that's not a very portable mount.)

[stargazerlily]

Thanks Stuart for your advice.

I hadn't thought about upgrading the mount ... would an EQ5 be a better mount then my EQ3?

Pete

[Sarah]

Thanks Stuart for your advice.

I hadn't thought about upgrading the mount ... would an EQ5 be a better mount then my EQ3?

Pete

Ideally you should look at an HEQ5 or better still an EQ6. It may be worth looking out for a secondhand one.

[haitch]

Whooaah now. Can we just go back to your original post?

You said you are mostly interested in planetary imaging? Well I shouldn't get hung up on a HEQ5 for that.

The superior tracking is only really needed for long exposure deep sky imaging - not for short exposure planetary/lunar. In fact your motorised dob idea would be just fine.

A heavier duty mount is always better for controlling vibration (especially coupled with a steel or wooden tripod v an aluminium one) but for what you are talking about I wouldn't go OTT. That said the HEQ5 or EQ6 option would stand you in good stead if your direction changed.

[Carbon Brush]

Time for another 2 pen'oth.

On the mount. Go for the biggest you can, it will give the most stable platform for the biggest scope, or combination that you try. Next week, or month, year you will see a 'must have' scope.

What is a biggest mount? With size goes £££ to buy and Kg to carry. The £££ happens only once. The Kg is with every use, unless you have a permanent fixture. You might be able to lift a number of Kg, but an unwieldy mount/tripod/counterweight assembly? Where are you carrying it? Stairs? Car? Narrow doorway? See if you can have a lift at a mount either from a friend, or from a shop. At the extremes, an EQ3, counterweight and tripod can be carried in one lump. An EQ6 is another matter.

If you are happy to find an object without goto, then you can save quite a few bob by going for RA drive only.

I used to have a Synta EQ5 with ali leg tripod. I tried my 8" & 10" Europas on it. Visually OK, but not rigid enough for photography.

I very recently got a CG5 goto with steel legs. Gives good rigitdity with an 8" scope (no longer have the 10"). Visually objects stay in view while I go away for ages. I have tried a couple of 300sec unguided exposures with good tracking. But have yet to do any serious long exposures to provide the full story.

Hope this is useful.

David.

[Sarah]

Whooaah now. Can we just go back to your original post?

You said you are mostly interested in planetary imaging? Well I shouldn't get hung on up on a HEQ5 for that.

A heavier duty mount is always better for controlling vibration (especially coupled with a steel or wooden tripod v an aluminium one) but for what you are talking about I wouldn't go OTT. That said the HEQ5 or EQ6 option would stand you in good stead if your direction changed.

Yes, sorry I should have said my suggestion of heavier mount is more to be future proofed, if you decide to go for heavier scope and/or decide to try some DSO imaging, in the future.

[Rossco72]

It is always better to have too much mount than not enough.

Amazing photos can be taken with 80-100mm scopes on great mounts. Your existing scope and barlow would give good results on a beefier mount

If a mount is rated for 20kg then putting around 10kg of scope / camera will generally give better results than 19.5kg

[stargazerlily]

Thanks everyone for your replies.

Haitch - yes, I'm into lunar and planetary imaging ... at the moment. I would really like to create better (ie less fuzzy) photos, hence the idea of up-scaling.

David - Carrying a heavier mount isn't a problem as I'm pretty fit (he says coughing and feeling generally weak and feeble). I set up the tripod and mount for each observing session and I only need to carry the mount about 10 feet from the garage.

Sarah - you make a very good point about being future proofed. I might become interested in DSO imaging in the future ... who knows.

Oh dear, I think I've got a bit of a dilemma ... do I go for a top notch mount (HEQ5) and keep my SW150PL (and won't see much difference in the images I can capture) or go for a bigger scope ... decisions, decisions.

Pete

PS: Sorry Stuart ... just seen your note. Perhaps I might see a difference in the images. Thanks

[sixela]

Thanks everyone for your replies.

Haitch - yes, I'm into lunar and planetary imaging ... at the moment. I would really like to create better (ie less fuzzy) photos, hence the idea of up-scaling.

If I were you, though, I'd make sure that you are indeed resolution limited with your current scope (i.e. that you're not limited by the thermal behaviour of the scope, your ability to focus, the seeing, your processing skills, how you configure the webcam etc.). If your photos really are fuzzy even when taking pictures at f/20-f/25 and a webcam sensor, then your scope is not the issue. A bigger scope is something you get to get larger image scale, not less fuzzy pictures.

If you aren't imaging at the current limits of your scope, then taking a bigger scope is just going to make it more frustrating.

[malc-c]

It's a tough choice... One thing that you do get with larger aperture scopes is more resolution, and more light grasp. Planets seem (are?) bigger in a large aperture, so IMO fitting a 6" scope to an HEQ5 / EQ6 would not give you much in more detail or what you can see. It will however provide an ideal platform if you opt for long exposure photography.

According to the blurb - an 8" scope gathers 77% more light than a 6" scope, a 10" gathers 56% more than an 8".... so if you want a wow factor and a sturdy mount then the equation is Appature + HEQ5 / EQ6 = ££££ !

Pete, I don't think anyone can really make up your mind for you... One thing for sure is that a new 200P on an HEQ5 is going to cost you over a grand... but they have excellent resale value. This will give you more object in your eyepiece, and will support additional weigh for guidescopes should you go down that route...Just my 2p worth

[Sarah]

I am not sure the extra aperture would make much difference on the planets or moon as they are already bright (although I am no expert!). Aperture is more important for viewing DSOs. It is focal length that magnifies the view so a bigger scope may well magnify the view a bit as it is likely a bigger scope is a bit longer, but this is not always the case. Looking at the spec of the 150PL and the 200P it looks like the 150PL has a long focal length anyway at 1200mm compared to 1000mm with the 200P.

[malc-c]

Agree, but take a look at some of the images of Saturn taken through a 130P, 150p, then a 200P and a 250P, typically using a SPC900 web cam and they get progressively larger and with a lot more detail the larger the scope, yet the focal ratio remains approx the same at f5. Yes, the 150PL has a longer focal length, which will give slightly more magnification, but the image will not be as bright for a given magnification when compared to a 200P or 250P. Mind you it's all academic... a 150P in the middle of a remote country village will out perform a 200P based in a town that's full of light polution

[stargazerlily]

Oh, this is too much ... too much ... too much hard thinking and decision making. What is a man to do???

Thanks Malcolm for your two-pennies worth ... excellent stuff. And you are right, I don't have over a grand to spend and more importantly, wouldn't be allowed to by SWMBO.

Perhaps I should re-phrase my original question. Do I want a short term big 'wow' or a long term investment ... bearing in mind that possibly I may not have the opportunity to purchase a big aperture OTA that I can use on the HEQ5 mount.

Thank you again everyone.

Pete

[Rossco72]

The "size" of the object is all about the focal length, the larger aperture will help with resolution but only if you have a higher resolution camera to make use of it.

For the moon and planets which are already bright, light gathering potential is less important. I truley believe that on your budget your scope is fine and there is plenty you can image with it.

[Luke]

It took me ages to realise that what affects the zoom is the focal length!

After I saw Saturn through a 150mm SCT, I thought, "Cool! Can't wait to see it a bit bigger through the 200mm Newtonian!!"

But when I looked through the Newtonian at Saturn, expecting it to be much bigger using the same high-mag eyepiece... it looked smaller!?!?!

I couldn't get my head around it because the Newt is so much bigger physically than the SCT!!

My 150mm SCT has a 1.5m focal length, the Newt is F5 and has 1m, so that was why Saturn looked bigger in the SCT with the same eyepiece!

[haitch]

Sometimes your choices are guided by what comes up for sale.

I started with a 6" on an EQ3 and was looking to move to an 8" or 10" on a bigger mount. Whilst browsing Astro Buy & Sell I saw and advert from Richard Day, the guy who builds the Skylight refractors, for a project he didn't have time for and I ended up with a 14" dob.

I must echo Rossco's sentiments on the capability of a 6" OTA for imaging. Visual astronomy would be a totally different matter.

Rossco I think your interests are pretty clear (despite your dob) seeing as you have an EP collection to make most astronomers dribble and yet in referring to f/l of scopes you only note the use of a higher resolution camera to make use of it rather than a shorter f/l ep.

It all depends what you want to do...

Spend hours on end on the pc learning how to process your images or look through a scope and marvel at the wonder of those photons that have been travelling your way since the dinosaurs were here.

I think the obvious solution would be to do a bit of both but that's even more expensive than just doing (deep sky) imaging.

[ollypenrice]

I think it important to joint the chorus of those pointing out that focal length and not aperture determine image scale. This is a simple fact. Aperture has nothing whatever to do with it. In planetary observation, or imaging, aperture will give you more resloution which you do need, and more light grasp, which you don't.

Like Stuart I think, Pete, that what you have should do pretty well if refined. A better mount would make things easier but you might need better collimation or some other tweaks to get your setup to sing.

Olly

[Rossco72]

We have all run out and bought something in haste and either regretted it or thought that it didn't deliver the WOW factor we had hoped for.

If the original query had been about visual then there is no substitute for aperture, but the OP specifically asked about imaging and for that there is little substitute for stability. Once you have a good mount you can get the best out of any scope before changing it. On a poor or overloaded mount then even a great £5 - £7k scope will give poor results if its shaking and vibrating at every breeze.

[stargazerlily]

This is a great thread. Your comments have given me lots to think about. Thank you!!

Stuart you are spot on about rushing out and buying something in haste and regretting it later. Been there, done that ... and definitely don't want to do it again.

Olly ... good point about the collimation. I've not checked the collimation since I bought the scope, which was over 2 years ago. That would be a good place to start.

I think I'm leaning towards getting a better mount.

Cheers

Pete

[Parus major]

I'm pretty much in the same boat as the OP but after a lot of consideration I'm buying a EQ6 Pro. The thinking is that an HEQ5 is the minimum required for imaging but the scope I get next isn't going to be the last scope I buy but the mount will last me a long, long time.

Basically, a HEQ5 limits me and a EQ6 pro is future proof for really any direction my interest takes me. I'm not got a great deal of expendable income so buying something I may have to cash in to upgrade in a couple of years isn't financially sound.

[Sarah]

Pete, what I was trying to say was that your existing scope should be fine. As others have said, if your primary interest wasn't lunar/planetary imaging then the advice you have received could be completely different. There are so many choices and options (and opinions) it is difficult at times to know what is the best thing to do.

Olly makes a good point about tweaking your existing scope.

Looking at a sturdier mount would hopefully be a long term improvement to your set up.

As already mentioned it is easy to buy something and then to regret your decision later. It is probably cheaper in the longer term to wait to buy the 'right' thing. Obviously budget plays a huge part of that decision making! I didn't realise how expensive astronomy would be and how, no matter what you have, there is always something else you could really do with!

[ollypenrice]

If you haven't collimated your Newt in 2 years I think you have identifeid the problem...

Oly