Cosmic Geoff

Nexstar 6 SLT - a good SCT OTA, but the mount is on the limit, with a wobbly tripod. OTOH, with some deals you are in effect getting the SLT mount for free. (Check the price of the OTA on its own!) You could get a better mount later. Skymax 127. A good Maksutov. Very few people ever complain about getting a bad Mak. Like the C6, a long focal length scope. You do not say what mount you propose to get with it. Skywatcher Star Discovery 150p. It's a 6" Newtonian with GoTo, but a cut price one. Non-collimatable main mirror, plastic parts, etc. Unlike the other two it has a short focal ratio. Your choice... You can observe deep sky objects with all three, but some wide objects will not fit in the fields of the first two.

No, you need a dovetail attached to the scope tube, via the scope rings. If you search the astro retailer sites for 'dovetail' you will see what a dovetail bar is, and with a bit more looking at pictures you will probably see how it is used. You could continue using your 130/900, but replace the EQ-2 mount and tripod with a GoTo mount and tripod. You cannot just change the mount head as the parts are not interchangeable. I suggest you look at some astro retailing sites to see images of small reflectors on GoTo mounts, to give you an idea of what you might end up with.

You are not the first person to want to do this, but it may not be as easy as you imagine. GoTo positioning is subject to some error in practice, so the error will need to be less than half the actual field of view of your camera sensor. What kind of large sensor? Not all DSLRs will give you the continuous live view you will require. A dedicated astro camera with a large sensor will be very expensive. How are you going to focus the camera? You will need a remote controlled motor focus or autofocus.

My recent EQ5 Synscan will allow me to slew the mount with the motors as soon as power is applied to the mount. In any case, so long as you have not done a star alignment you can release the clutches and move the mount manually without affecting anything. I do not see why adding a Polemaster would affect this advice.

Learning your way around the night sky requires a bit of effort, starting with buying a night sky atlas like Norton's and/or one of the books that give a monthly guide of what to look at. There are also various websites. If you definitely want a GoTo (they are great once you have learnt how to use it) you have various options, which require some decisions: You could clamp your telescope straight onto a GoTo mount, as your telescope almost certainly has a standard dovetail clamp fitting. Or you could change the whole system. Gotos fall into two main designs: the alt-azimuth (commonly a single arm) and the German equatorial. The latter design is needed for long exposure astro-photography but for visual use mainly introduces the annoying and unnecessary complication of an equatorial mount which needs polar alignment. Then there are different operating systems: Celestron's Nexstar, Skywatcher's Synscan and a number of others. These actually differ significantly in features and ease of use. IMHO the Nexstar is easier to use than the Synscan. You can buy all the Skywatcher mounts on their own, but some of the Celestron mounts, particularly alt-azimuth, are only available bundled with a scope. Mounts come with a tripod and I would not recommend trying to retain the EQ-2 tripod.

Photography of what? It is possible to mix visual use and planetary imaging on the same telescope, but for deep sky imaging you need totally different kit. SLR? Do you mean a DSLR? Nobody uses film for astrophotography anymore. Some people use iphones (because they have one) but this is not ideal. DSLRs are used for deep sky imaging, partly because they have big sensors and are usually cheaper than buying a dedicated astro camera with a big sensor, partly because a lot of people have one already. For planetary imaging you need a specialist planetary video camera, which replaces the eyepiece.

The scope is bigger than I'd recommend for your situation, and the tripod is far too big for your balcony, and the mount & tripod are too big and heavy to carry downstairs when you want to go to a remote site. The mount is an equatorial Synscan. Have you any idea how difficult it would be to align that properly on a balcony? And BTW, if you select objects from a list and GoTo them, half the time the scope will slew to point at the building. FYI, an EQ-5 tripod fully extended stands on a triangle 120cm a side, or about 110 cm from base to apex.

With great respect, I think you need to do more research into the subject. There is no such thing as a 'best of both worlds' scope. It's like trying to buy an automobile that is suitable for use as a pickup truck and for oval racing. A hyperstar is, by all accounts, for 'advanced astro-imagers only', and not something you would want to swap on and off. Yes, a 2350mm f/10 is ill-suited to DSOs. Every expert will advise you to start with someting like a 80mm apochromatic refractor of about 500mm focal length. The reasons are too technical to explain briefly here. Over here, we advise every would-be astrophotographer to read a book called "Making Every Photon Count" by Steve Richards. If you can get a copy, I recommend you read it. It could save you a lot of wasted time and money. From personal experience, I have not delved seriously into astroimaging, but many of the deep-space images I took with a 102mm f5 refractor were quite pretty, while all those I took through a 203mm f10 SCT were rubbish.

Are you serious?😲 The balcony is clearly much too small to fully deploy the EQ-5 tripod with a 200/1000 Newtonian on it. The Newtonian eyepiece will be close to the edge of the balcony also. The same remarks apply with slightly less force to a 150/750 newtonian and mount - there will not be enough room to deploy the scope and work around it. I suggest that considering the lack of space and the likely poor seeing because of the proximity to the building, you consider a smaller and more compact design of scope with an eyepiece at the back end, e.g. a 102mm or 127mm Maksutov. This is still enough aperture to give you many hours of pleasure on suitable targets.

What are you planning to use the scope for? If you intend to use it for deep space astrophotography, you should consider buying a short focal length telescope more suited for the purpose. If it is for visual only, the mounts bundled with it by Celestron would be adequate, and an EQ6-R would probably be overkill.

Do you want a GoTo mount or do you want to 'keep it simple'? Are you interested in taking up Astrophotography?

I have no particular criticisms. The eyepieces that came with it were not that great but that applies to any lower priced outfit you might buy. The Barlow that came with it somewhat improves the performance on planets, and this Barlow seemed to work just as well as a Celestron Omni x2 Barlow I bought recently, originally priced at £50. My Startravel OTA came with a terrestial 45 deg diagonal, but fortunately I had a a spare star diagonal. Major parts of the OTA and focuser are all metal. The terrestial diagonal is actually useful if you want a RACI image to avoid swapping your brain L/R, but does not give as sharp an image as a star diagonal.

That might be an over-reaction. This is the right kind of camera for planetary imaging (unlike a DSLR) and this model was much favoured for planetary imaging a while ago though one does not hear so much about it now.

If you want a widefield 'scope with which to learn the sky, you could do worse than get the Sky-watcher Startravel 102 (102mm aperture, 500mm focal length). It is inexpensive, quite well made, similar to the Evostars, and easy to handle (I normally carry mine in one hand). It also works surprisingly well for dabbling in EEVA and astro-imaging. On the downside, it has some chromatic aberration and field distortion, and is not much good for high power work (e.g. planets) but you can't have everything unless you want to spend 896 Euros + shipping. (see above). The Startravel should mount on your existing tripod.

I have a pair of these bought some years ago. They work fine for day or night use, but I did have to recollimate them after a while. Considering how much you can pay for premium binoculars I thought they were an absolute bargain.

A GoTo Dob is a lot more expensive than a basic manual Dob. You should question whether you would not prefer a SCT on a GoTo mount (affordable if used, and much more compact), or a Newtonian on a GoTo mount (more potential for forays into basic imaging, or mounting alternative scopes.) A suitable Eq GoTo mount for an 8" Newtonian is likely to cost you more than I paid for my C8 SE outfit (used). BTW, I had a Newtonian on a manual equatorial mount, and I thought the combination was horrible and user-unfriendly.

While doing some solar observing just now, it occurred to me that unless your mirror is smashed into tiny bits like an auto windscreen, you should be able to use the biggest piece to determine the focal length. Set it up so that it focuses an image of the Sun back onto a piece of white card, and measure the mirror-to-image distance. This will give you the focal length with a reasonable degree of accuracy. Armed with the diameter and focal length, you can then get quotes for a mirror from amateur telescope makers and other optical specialists. Once you have an agreement in principle, you can give the maker the bits to play with, so that he can confirm the focal length and figure (spherical or ???). Given that a MN 190, smaller than your scope, costs around £1000, this approach may prove cost-effective.

What about the screen and keyboard? I use a Windows 7 Dell Vostro laptop (look it up) at the telescope for planetary imaging and some processing, which suggests the requirements are not too demanding.

IIRC the Powerseeker is not highly regarded, but the Celestron Nexstar 6SE is a decent piece of kit. It has the same mount as the C8 SE.

We should have asked before (or you could have told us) - what model of mount is it?

With the latest version, Synscan gives you a slightly cryptic readout of how accurate your polar alignment was, which you can fine-tune or ignore. If you mechanically polar aligned on Polaris, it will therefore indicate a small error. If you try using it to GoTo objects, you will find out how good the polar alignment is in practice. I suspect that any polar alignment will prove good enough for visual use. (Remember that alt-azimuth GoTos work just fine and they are not polar aligned at all.) A very precise polar alignment is only required for long exposure astrophotography.

Did you mean 'Synscan software'? If you did, the latest versions offer you the option of fine-tuning the polar alignment after a successful 2-star or 3-star align. The exact details are too complicated to quickly explain here. Try it and study the manual.

The original concept of the Dobsonian was that you could build your own using junk parts rather than buying a factory made scope and mount at a fancy price. Alternatively, it should be possible to source a ready-made base if you search around, but your budget is low. Making a base shoud be a straightforward DIY project - the Skywatcher ones are made of chipboard, I believe. Also budget for a finder scope (various options) and eyepieces at around $50 each. I'll note in passing that in theory you could fit the tube with tube rings and dovetail bar and mount it on a german eqiatorial mount, but this would be rather expensive.

Today I dug out a couple of dew heater bands (large and small) from my spares box and measured their resistances. Together they would consume 1.75 amps at 12 volts. That would flatten a 17AH battery pack in about 9 hours.

The older Canon DSLRs are fine for day use but not user-friendly for astro use compared with newer models which have liveview etc. Try focusing through the viewfinder on a bright star and cross your fingers.