Narrowed it down but still need help with final new scope choice please

[**Space*Hopper**]

Hi all,

I have been learning from the amazing amount of useful info on this forum for ages now but have only just got around to joining so firstly a big hi to everyone

My trusty Skywatcher 130PM has served me well and last year I even managed to successfully image saturn with a webcam through it :shock: But now I am looking at buying a new scope, partly driven by my newly found addiction to imaging astro objects and also by the fact that my Canon 400D will not focus on this scope Once I had got over the initial disapointment of this fact, just as an experiment I attached my 400D to my sons 80mm f/400mm scope which we bought from a car boot sale last year, (the objective lens has seen better days and the scope is not even branded). Using this on my motorised EQ2 mount I have been able to image M45 and M42 and the results far exceeded my expectations and this got me to thinking that perhaps I do not need to spend as much as I had initialy thought on my next scope. Consiquently my initially long list has now shrunk down to just 3 scopes, (although please feel free to mention others if you think I am missing a gem somewhere).

(1) Skywatcher Startravel 102 f/500

(2) Skywatcher Evostar 102 f/1000

(3) Tal 100RS f/1000

Some of the ones I have taken off my list are :

(1) Skywatcher Evostar 80ED1 PRO - I know these are the bees knees but having seen the results from my son's tatty old scope I simply cant justify spending this sort of money ,(maybe I am just to easily satisfied but hey).

(2) Startravel and Evostar models with objective lenses of 120mm and above as I have been reading many reports of CA once the size increases to this sort of level. What do you think, are these reports exagerated ?

(3) Skywatcher models 150 and above, I appreciate that these are great scopes but having seen what a small refractor is capable of I am not going to continue down the reflector root, (I admit it - I'm lazy ! ).

Anyway now for some questions :

(1) Will the 3 models that remain on my list achieve focus with my 400D ?

(2) Is any one of them better suited for imaging with the 400D ?

(3) Is it better to go for a shorter focal length scope and add a barlow when needed or a longer focal length scope and add a focal reducer when needed ?

Having whitnessed what can be done with my sons f/400 scope, (and the objects I have looked at so far have been nicely framed), I am very tempted by the Startravel 102 f/500 as images can always be made larger with my existing barlows or even in paintshop and the small size of the scope makes is very easy to transport, handle and store. On the other hand part of me thinks that the greater magnification of the f/1000 scopes listed might come in handy at times but then again are the resulting images going to be too big to fit on the chip of the 400D and therefore require a focal reducer, (which I would need to buy), and also make it harder to achieve good tracking ?

I feel that I have come a long way but my head is hurting and I really would be very grateful for some guidance before I make my final decission.

Please, please, please feel free to comment on any aspect of this post and bring to my attention anything that you feel might be beneficial.

Thanks in advance

:wave:

Ian

[John]

Hi Ian,

I'm not an imager but, of the 3 scopes you have shortlisted I know that the TAL will have the best optics. Others can comment more knowledgably than I on it's imaging capability and compatibility with your camera. The 102 F/5 is a nice grab and go scope but does have a fair amount of false colour - the TAL has very little for an achromat.

Of course the ED80 is very popular with imagers as you know - that has virtually no false colour and is optically excellent

John

[shepsboss]

Great question, I have a 400D and have not yet bought a scope, so I look forward to the replies! Are you looking at short or long exposure? I only intend to try short exposure, too much cost involved in realistic long exposure.

[Zakalwe]

Less about the 'scope....what mount do you intend to use?

The HEQ5 is probably the minimum that you should aim for, with the EQ6 giving you more load capacity.

The mount is probably more important in imaging than the scope....

[Zakalwe]

Hi Ian,

I'm not an imager but, of the 3 scopes you have shortlisted I know that the TAL will have the best optics. Others can comment more knowledgably than I on it's imaging capability and compatibility with your camera. The 102 F/5 is a nice grab and go scope but does have a fair amount of false colour - the TAL has very little for an achromat.

Of course the ED80 is very popular with imagers as you know - that has virtually no false colour and is optically excellent

John

If you are going down the imaging route, then you would want a short focal length 'scope. The longer the focal length, then the more accurate the tracking needs to be (and back to my other point about the mount). The TAL is a F10 'scope (I think) and would need very good guiding.

For DSO imaging, I would go with the 80ED.

I have gone through similar thought processes to Spacehopper, and I have ended up opting for an Equinox 80 mounted on an EQ6 mount. The mount was the best I could afford, as I know that it will allow me some headroom in the future. Very quickly, I have added another 80mm 'scope for guiding. Once you start to add on cameras (imaging and guiding), dual mount bars, dew-heaters, heater controllers, USB hubs, camera controllers etc, you soon end up with something that the Borg would be proud off. Then you will be glad of the extra capability of the mount.

The type of imaging that you want to do will decide on your setup. if it is mainly planetary and Lunar, then a long focal length 'scope is what's required (a SCT would be spot on). Tracking isn't that important, as you will be grabbing short .avis to stack.

If you are going for DSO imaging, then you will be using relatively long exposures, even when stacking. To get long exposures without star-trails, then you will need a decent mount (again, there are exceptions....there was a recent thread where someone got superb images using a DSLR, a standard (though very expensive) prime camera lens and an unguided tripod. He stacked 700+ exposures, all a couple of seconds long). Anything over about 2 minutes will probably require guiding (though I have managed to do 200 second exposures without guiding. Others have done >4 minutes unguided).

DSO imaging is expensive. My imaging rig stands me about £2700, and I think that it is fairly marginal. I am now looking at a cooled CCD, which will be a minimum of another £800

NEQ6 Syntrek mount = £780

Canon 50D = £700 (a couple of years old now. You could use a 1000D at about £250)

Equinox Pro 80= £480

Field Flattener = £70

QHY5 guide camera =£180

2nd hand ED80 guidescope = £120 (an ST80 worth £80 would do, or indeed a finderscope)

Dew strips, Dew controller = £100

Dual Mount Bar = £100

Laptop = £350

Power supplies, cables, hubs, odds and sods, = £100

[Damo636]

I originally bought my Tal 100RS to try my hand at some astro photography. Have since given up on the idea due to the cost involved. All I can add is that the Tal is optically very very good.