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Bowdie

upgrade to a goto scope

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Hi,

Last year I purchased my first telescope, a SW dob 250p. I loved getting out there and finding planets (with some great views) but was left disappointed as I struggled to find any DSO that this size of aperture may allow me to see. Feeling frustrated I resolved to save for a goto scope and a year later I am now researching for my nexw scope. At the moment I am thinking the celestron advanced series C9.25. I have chosen this scope due to the similar size aperture of my dob and the prospect going in to imaging next year one i save up for a ccd.

Does anyone have any experience / recommendations for this scope or similar and any suggestions for a ccd that i could grow in to?

Thanks!

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I have the CPC version of this ota and it's a fine scope for a lot of stuff from planets to star fields. It has a long focal length and slow f-ratio giving great views/images of planets - and very capable imaging dso's with a reducer. However - It's not going to necessarily resolve your issue with finding dso's.

It'll point you in the right direction for sure - but you still need to know how to "look" at the deeper objects, how to judge the conditions, and know what to expect. I know someone who had the same idea of using goto to solve their dob pointing issues but got so frustrated that in the end sold up all their kit. Your ten inch dob is still the better tool for viewing dso's.

If you're going into imaging however then a good equatorial mount is essential and for the 925 I'd recommend an HEQ5 pro minimum but preferably NEQ6 pro (or similar size/weight). Imaging is a steep learning curve and you'll need to save a lot to do it effectively. You should get a lot of comments on this but hope that helps. :)

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Have you tried everything though before going down the GOTO route?

There might be cheaper fixes.

Things like Telrads, RDFs, right angled correct image finders, monthly planispheres (from magazines or off the web), star maps, Stellarium and the like can help.

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I agree on caution. With cone error, inaccurate polar alignment etc. etc. GOTO does not always GOTO! It will put you in right area(ish) and then it's up to the mark1 eyeball, telrad etc. and to get aligned, you need to know the alignment stars anyway.

Typed by me, using fumms...

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I would echo the caution too - I have an HEQ5 Pro (Go to) and it has been a steep learning curve to be able to set it up and star align successfully every time and it is not that quick even if you do it only fairly accurately. From my experience as a relative newbie to astronomy I can't stress how much help joining a local astro society was or attending an observing evening given by a society. To be shown DSOs by someone through a similar telescope to yours would I think really help to see what you are looking for. Personally I think finding a faint fuzzy yourself with a bit of training in star-hopping is much more satisfying than spending some of your precious observing time setting up a go-to - the view will be the same but the satisfaction level is something else. If I can manually find one new object in a night's observing I am over the moon. That said Go-to is great if you want to image something you can't acutually see in your eyepiece and for speed and I do use it now I have mastered the dark art of polar and star alignment especially if I am finding things for others to see.

I'll leave it to others to assist on the CCD etc - just don't give up on the Dobby they're great for learning the sky and 10" is a good size.

Hope that helps.

Cheryl

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I agree with the others. If you're not finding any DSOs then something major is wrong. It's really not that hard to find the brighter ones. What have you tried so far?

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Hold on a second.

I'm gonna give a vote for GoTo. You need to do a reasonable polar align, and the GoTo needs at least a two star alignment to be any good - all the better if you add calibration stars near the target you are looking for... but after that, and in my experience, your target will be in the field of view. This is true for my 2800 f/l HD11 with a 10mm EP. I can do the polar align and GoTo calibration in about 10 minutes...

But the C9.25 - while an excellent scope I am sure (and no doubt the gem of the Celestron range) has quite a long focal length, slowish optics and will be a bit more difficult to guide.

My question is: why don't you buy a capable GoTo mount and some tube rings and mount your existing Dob tube on that? You get great views and with a suitable coma corrector you'll have the basis of a very good imaging set up too.

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Oh, and GoTo mounts should be shipped with an illuninated reticle eyepiece; it really is obligatory for setting the thing up... least with anything more that a 750mm f/l scope...

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Even a modicom of LP makes DSO finding nigh on impossible. M31 is always said to be a naked eye object. Not 15 miles from central London I'm afraid!

Even with star hopping it is difficult to pin down.

I first bought a cheap ETX-80 for this very reason. I saw more DSOs with it in one night than in the whole preceding year.

I think if you're losing your astronomy mojo, then GOTO is the way to go.

If you can though, keep the dob and get a small; cheap GOTO. Use them side by side - Goto to get you there and dob to get the great views!

TheThing

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Oh, and GoTo mounts should be shipped with an illuninated reticle eyepiece; it really is obligatory for setting the thing up... least with anything more that a 750mm f/l scope...

Have to say, I've never found one in the box but your right, they are essential.

Typed by me, using fumms...

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maybe try some setting circles and a Wixey ... I'm rubbish at finding stuff, but with the cheap addition of these two I've found M33, M13, Double cluster, Ring etc. have a go with these first and it'll only cost you about £40 - 60 ish.

Plus you still get the feeling that 'you' found it :grin:

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If you mount your dob on an equatorial mount it will have to be an NEQ6 Pro due to the size of it. This will be good enough for visual on a calm night - but the slightest breeze will spoil any imaging attempts more often than not. It's a good alternative for smaller ota's however.

The idea of a smaller cheap goto to "fill the gap" is cool - but very faint dso's really need aperture. The idea of a wixey and setting circle mod for your dob (which shouldn't cost more than around £30) is a good first step to consider to help solve the "finding" issue.

Another idea would be to get any equatorial mount like a CG5 GT goto or HEQ5 Pro and pop a half decent refractor on it - someting like a GT81 or ED80, ED100 etc would make for a great ccd imaging rig for dso's. Then you could keep your imaging and observing scopes separate - it's allways problematic trying to combine both techniques in a single scope. :)

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It takes time and patience to learn the sky and where to look. It always surprises me the number of folk at star parties with super equipment ,yet unable to locate constellations.

Once you have a star map and look up, it's rather like looking at a world atlas. You know where the countires are and even some cities DSOs).

A 10 inch Dob should show you about 95% of deep sky objects, but stick to good realistic targets. M1 is not stunning,same for M33 and M101.The planetary nebulae are stunning and being blue/green can be picked out from the background. Both globular and open clusters are good. You'll need more dark sky for nebulae and dust clouds and fainter galaxies.

I'd stick with the superb Dob and invest time in learning all you can. There is quite a thrill from finding DSOs, neat,

Nick.

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That's good advice, but M33 and M101 are stunning if the skies are dark and the conditions are good. M33 in particular is one of the most amazing DSOs under good conditions. EDIT: What I'm getting at is that of course it's best to go for stuff that will look good from your site. However, if the light pollution is so bad that you have hardly any stars to star hop from, then DSOs are never going to look good.

Edited by umadog

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Thanks for your encouragement! I'm going to look at modding my dob with a setting circle and wixey first. I guess imaging can wait until I know more about the night skies... Though I like the idea of a smaller go to for planetary images...

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i had the wixey and a compass rather than a setting circle and i could find 80-90% of objects using stellarium co ordinates ,however i now have a 200 flextube goto and it hits 100% everytime [as long as you set up the 2 star alignment properly] however for the extra money it cost i dont know if it is worth it [got mine second hand so not as big a hit as it would have been] and i'm now in the process of getting a 5" frac on an eq mount just to get back into star hoping.using stellarium and a compass ,

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Its been mentioned and i will mention it again, get a Telrad, download the free maps and Stellerium use the Telrad rings in Stellarium to match what your viewing, a little practice and you will be sitting on top of your chosen DSO, then its just a matter of recognizing it as a grey fuzzy blob in most case very faint, check the magnitude of DSO around a Mag 9 and your close to your limit depending on your LP, for viewing something to blow your mind, look for Clusters, there easy to find and really nice to view...

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Telrad or equivalent is essential. I couldn't find a thing except the moon and planets in the supplied finderscope. Even a simple rdf is able to pinpoint what you're looking at.

The printable charts for Messiers and Caldwells are excellent, neat.

Nick.

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