Scope Advice Upgrade for imaging.

[Mr TamiyaCowboy]

hello first of i best mention my current set up i have. 

SW jones birdy type 114 catadipotric @ 1000mm FL and F8 ( its about F7.8)

image sensor wise i run both a canon 350D unmodded , and also have MS HD5000 webcam converted astrocam.

to go with my canon dslr i also have the canon nifty 50mm F1.8 II and the old canon 90-300mm telezoom.

I also own the Skywatcher merlin multi function goto mount, running both astro tracking and panoramic settings software.

i am now bored with trying to image jupiter ( long story) , the sun in white light and having to have others cart my gear around.

the eq-1 is old knackered and useless with more wobble than a plate of jelly.

my canon is unmodded so that holds me back somewhat. and my 1000mm scope is a tad too long and slow.

i have saved up my last pennys and have enough to purchase a second scope ( i mean cheap scope well under 100 GBP)

now i want to shoot some large DSO, like m32 , orion maybe even the horse head ( i never knew it was in orions belt )

so the scope : i have looked at the SW 80mm travel scope and it is a bit far from my budget, but i have found the celestron 70mm

travel scope with a fast f5 and a 400mm fl , i have googled so many images that were said to have been shot with the 70mm

and some even show DSO's , so ............. 

is it worth purchasing the 70MM travel scope from celestron its right on the edge of my current budget at £60,

it is small enough to cart around in a bag with my merlin panoramic head and my canon camera, but will it allow me to shoot some of the bigger DSO's

Has anyone in SGL used said telescope and captured decent widefield DSO's with the scope and would it fill the gap for my imaging with

canon lenses and/or the cheap SW 114 birdy jones telescope 

[rowan46]

I doubt many dso's have been captured on the merlin mount as its the wrong kind of mount. your best bet as an intro to long exposure imaging is to use camera and lens on your eq1. you really are better off with a driven eq mount for imaging rather than an alt az mount because of field rotation

[nmoushon]

With a budget so small (For AP that is, as AP is an expensive hobby) I would actually suggest trying to find another good lens for your camera instead of a scope. I believe that the 70mm scope you are looking at is a short tube Achromatic refractor. This will produce very bad CA in your images. I don't know much about your mount but a quick search showed that its an Alt/Az mount. This isn't the best for DSOs. This will limit your exposures because of field rotation. The longer your FL the fast the becomes an issue. This is why I am suggesting a lens over a scope. There are several lenses in the 100-200mm range that have a set FL like your 50mm. This, I think, will give you the best options for shooting DSOs. But again because of your mount your exposure lengths will be limited. Your mount is fine for planetary, sun, lunar imaging but not so much for long exposure DSO imaging.

[Mr TamiyaCowboy]

i was lead to believe that field rotation happens with any telescope.

the reason being poorly aligned mounts, and field rotation can be corrected, use green channel as base and rotate red and blue to 

correct ? its work but could be sorted out via software tweeks after imaging session

in the imaging section people have said its not even worth thinking about trying DSO with a eq-1

they just are not accurate enough. sloppy and very out of accuracy , very flimsy ie the tripod legs themselves.

ok for eyeball viewing, hence why i chose a goto altaz 

my eq-1 is driven by a single motor on the RA , nowt else and there are no dual motor kits for the eq-1 either.

my camera has NO live view so everything is focused via the viewfinder, trust me when i say it takes like 30 mins to get the nifty fifty to infinity

or near abouts. about 5 mins is the moon is out and autofocus can lock on, but still requires slight adjustments.

i use my canon lenses for lunar disc's and daytime photography. i gave up struggling to focus stuff in the pitch black of night.

so a second camera lens would be used again only for lunar and daytime imaging.

i dumped a fair bit of money into the hobby already to, the scope and eq-1 cost me £120, the merlin out cost me £140

and all my canon stuff came in at £240, thats £600 and im stuck to an eq-1 with a bad sw 114 scope ( it has a barlow lens inside the focuser tube)

thats got more wobble than rountrees strawberry jelly, and an ALTAZ mount thats good for photographing planets and the sun. 

feel i am at a low ebb with this darn hobby now to be honest

[nmoushon]

i was lead to believe that field rotation happens with any telescope.

the reason being poorly aligned mounts, and field rotation can be corrected, use green channel as base and rotate red and blue to 

correct ? its work but could be sorted out via software tweeks after imaging session

in the imaging section people have said its not even worth thinking about trying DSO with a eq-1

they just are not accurate enough. sloppy and very out of accuracy , very flimsy ie the tripod legs themselves.

ok for eyeball viewing, hence why i chose a goto altaz 

my eq-1 is driven by a single motor on the RA , nowt else and there are no dual motor kits for the eq-1 either.

my camera has NO live view so everything is focused via the viewfinder, trust me when i say it takes like 30 mins to get the nifty fifty to infinity

or near abouts. about 5 mins is the moon is out and autofocus can lock on, but still requires slight adjustments.

i use my canon lenses for lunar disc's and daytime photography. i gave up struggling to focus stuff in the pitch black of night.

so a second camera lens would be used again only for lunar and daytime imaging.

i dumped a fair bit of money into the hobby already to, the scope and eq-1 cost me £120, the merlin out cost me £140

and all my canon stuff came in at £240, thats £600 and im stuck to an eq-1 with a bad sw 114 scope ( it has a barlow lens inside the focuser tube)

thats got more wobble than rountrees strawberry jelly, and an ALTAZ mount thats good for photographing planets and the sun. 

feel i am at a low ebb with this darn hobby now to be honest

Unfortunately the AP side of this hobby is expensive. No way around it. Even the cheap side is a lot of money.

In regards the field rotation. There are ways around it. DSS will stack the images but each image will be slightly rotated from the next and thus cause a very jagged edge all the way around. This isn't a problem unless your doing mosaics. you can just crop it out and your fine. But that only works up to a certain length of exposure. If you try taking a very long exposure the picture will smear across the image as it is rotating. The FL of the lens/scope will determine how long of the exposure you can get away with with out seeing effects.

Your eq-1, even with a motor, is not very good for AP. Main reason is because of its inaccuracy and that it can't support a lot of weight. This is another reason why I suggested getting a new lens. The camera and lens are MUCH leighter than a scope and camera of the same focal length. Your eq-1 mount will be able to handle the camera and lens much better. Its still not the best but will be better than trying to put a scope on it. So if you use short focal lengths, like your 50mm lens, on your eq-1 OR merlin mount you should be able to get some decent shots. You'll have to test each to see what kind of exposure length you'll be able to get to. The eq-1 will not have the field rotation but might loose some subs because of wobbliness and the merlin will have field rotation but can be cropped out.

I know without live view focus can be a pain. Especially at the shorter focal lengths. The easiest way is with the moon or a very bright star or planet. If you can get the moon in focus the rest of the sky should be in focus. Take a quick pic and then use the display to zoom in and check for focus. This is how I did it with my dslr even though I had live view. If you are using a planet or bright star take a quick pic and try to get the star/planet as small of a circle as you can. This will be the best bet to get focus unless you want to hook it up to a laptop. Lenses are used in ultra wide field imaging very often! There are some very very large nebula out there that can't be imaged as a whole without a lens or a mosaic.

[rowan46]

field rotation isn't a scope issue its a mount issue  an alt az mount can track the  stars as they apparently move across the heavens but it cant cope with the rotation that is also involved thats why the eq mount is needed. It only needs an ra drive and good polar alignment. You may not get hugely long exposures but with a bit of luck and a short lens you may get up to a couple of minutes out of an eq1 stack a few of them and you may have got some photo's you want to keep. Alternatively try some star trail photography

[Alien 13]

I agree with the the previous posts regarding using your camera with a lens but i would suggest you might look at getting an old M42 type 35mm film camera  lens and adapter these are manual focus and are easier to use for astro work as they all have an infinity hard stop.

I would suggest any quality prime lens from 50mm to 135mm will give good results and with either mount you may get 1 to 2 mins worth of exposure which will be enough to capture some good images it wont be easy though AP never is.  

Alan