Ideas for mount and scope for astrophotography

[Mountain_Wanderer]

G'day all.

I'm in the middle of looking for my first telescope and am considering getting a 10 inch newtonian dobsonian. Later I plan on upgrading to an eq mount for astrophotography and I'm trying to work out the following:

- Is a 10 inch newtonian tube good enough for astrophotography or would I likely be needing another scope such as a larger newtonian or something like a refractor? I hear 12 inch newtonians can't really be supported on eq mounts so I guess a refractor would be the choice? How much better is a refractor compared to a 10 inch newtonian or is the 10 inch OK and likely to achieve great astrophotos for a long time? Is the 10 inch newtonian considered a beginners astrophotography scope or can it be used for a lot of stuff up to advanced level photography?

- What type of mount would I need for a 10 inch newtonian? I hear the HEQ6 is inadequate?

- If I want to be covered for astrophotography for ever, what type of mount would I need? Would a HEQ6 mount be enough or is there bigger/larger mounts which I'd need? Is is safe to think that if I mount can support a 10 inch newtonian then it can support any scope (refractor and/or other)?

I ask all this because I have the choice of either buying the 10 inch dobsonian solid tube, therefore covering me for future astrophotography, or I can just get the 10 inch collapsible dob. The collapsible is much easier to transport around, however If I knew that the solid tube version was worth getting because it would be excellent for future astrophotography then I think I'd get that. However, if the 10 inch solid tube doesn't seem good enough for photography then I might as well just get the 10 inch collapsible dob and then later on buy a completely new scope and mount specifically for astrophotography - despite all the additional cost involved.

Whatya recon?

Jowel

[ArcaneMagik]

My opinion is;

10 inch dob is a perfect scope for starting if you can handle the size and weight. You will enjoy the view, and it is so quick to set up.

As for astrophoto, you would need to shorten the tube and it would be close to the upper limit of an HEQ6 to carry. I would look at a different scope at that point just so I could keep the dob for something to do when the other scope is busy.

[OzRob]

I think you are best off getting the 10 inch collapsible dob to start out with and forget about what may eventuate in the future. The SW dod on Andrews is great value at $700. I think starting AP with a 10" on a EQ6 would be hard work.

The beauty with refractors is that you can get one with a short focal length. This will give you lovely wide views of the sky. An added advantage is that for AP you don't have to have everything spot on to get a good photo. Tracking errors are not so critical. This allows you to learn AP at the same time as generating good photos. I would hate to spend all that money and then give it away due to the frustration of not getting everything working. Although don't expect to have no frustrations with a refractor.....lol

[Alchemy]

Interesting call, you seem highly interested in a 10 inch dob, I imagine it would be ok on a eq6 pro, the solid tube gives you the photography option later on.

What to buy for an ever after setup is hard to determine, people sway from one thing to another, I went from a 90 mm refractor to an 8 inch cad, to am12 inch reflector, then to a 132 mm refractor. The refractor suits me at the moment, no collimating simple to use, far more stable than the 12 inch, lighter too.

If you wanted to be covered for every combination of astrophotography just get a paramount.... That's a very expensive mount !!!! But will handle just about anything going.

My advice is start simple, see if you like it, find your niche and then spend the bucks. Plenty of stunning images arebtaken with dslr cameras, short fl refractors, wide open astrographs, uber long fl stuff, so find what appeals to you. Note the longer fl you go the higher quality gear you generally need.

The collapsible dob will not be a good imaging scope.

[DRCORTEX]

I agree with not getting the DOB for astrophotography, unless you want to simply do short exposure planetary imaging.

If you want to shoot for DSO's ( Galaxies, etc ), you are going to need an autoguide, and a DOB won't do that, even those that have an autotrack, due to it being an alt-az mount, and not compensating for field rotation, etc. For DSO's an EQ mount is really the best option.

Think long and hard, because those faint little fuzzies are difficult to capture. I've been trying for a while now, and it takes a lot of work.

Even getting to the point where you have the right scope/mount, etc, brings up even more questions.

Stick to planetary for now if you really want a DOB, great low cost visual scopes, stick a Tucam or such on.

Cheers
DOC

[NorthernLight]

Go for a 12" Dob and forget about AP for now. If you got the financial commitment spend the extra 200bugs and go for the max.
AP is totally different, trust me. I started with a 6" EQ mounted scope and was amazed by what can be seen with it, more so when I went under truely dark skies. But then I wanted to take pictures of what I saw and started with getting a DSLR (and a decent lens=2k) then of course I needed a better tracking mount (NEQ6PRO=2k) then I needed a guide scope and a guide camera (ED80+OSSAG+rails and stuff=2k) then I wanted to shoot from true dark skies so I needed a battery to support the laptop and the mount and a bigger car and an emergency tent (for when it starts to rain before you can pack up) and a laser to align the gear and a big toolbox to store all the cables, cams, adaptors, tools, masks etc.=never ending story. And once you get a decent image and compare it to the ones in the glossy papers-you want more=cooled CCD´s, RC´s, Paramount´s, you name it.
After I took a deep breath and reminded myself that I actually just wanted to take pictures of what I saw (without spending hours reading books about photoshop and twice the time using that knowledge) I came to realise that a 6" newton and a DSLR is really all I need for AP. But I really want, for the hours that pass whilst automated exposures, is a huge dob to roam the sky and be amazed. My next call is either a 16" lightbridge with my current eypieces or a 12" GSO with Naglers.
My two cents for what its worth.
Cheers

[ballaratdragons]

Guys, there is no such thing as a HEQ6.
Yes, some people call the EQ6 a HEQ6 but there is really no such thing.

There is a HEQ5 or an EQ6 (and an NEQ6 but it is just an EQ6 with a wider dovetail and a counterweight shaft extension) :thumbsup:

And maybe an EQ7 but it is only vapourware at the moment :lol:

[Astroman]

Mounts aside, if you are only starting out, get the 10" Newtonian on a dob base, it will serve you well and give you many great views of the sky... Leave Astrophotography until you are ready to take the plunge, but you can always build up an equipment list along the way, ie. cameras, adapters... etc...

Forgot to mention, get yourself some good eyepieces also this will dramatically improve your viewing pleasure, while you wait to purchase the Photo gear.

Later the EQ6 will carry the 10" with no problems, you would just have to source some OTA rings for it.

Good luck with the purchase....

[RobF]

Jowel, I can't remember but I don't think Focal length and Field of View have come up in your astrophotographical musings so far. Apart from the weight/balance difficulties of a 10" dob on an EQ mount which will make your learning curve that much more tricky and frustrating, the longish focal length (usually 1.2 metres) and tight FOV (about 45x30 arc mins?) means your tracking has to be spot on (one of the hardest things to get right when you're learning) and your view is quite tight and "zoomed in".

This is the other reason people like high quality refractors like Tak's - wide FOV, shorter FL (around 700mm) to get in more sky, wide imaging circle with very flat FOV. There's an excellent freeware application called CCDCalc that let's you gauge the effect of these variables on commonly imaged objects that might be worth a play if you end up seriously planning things for imaging:
http://www.newastro.com/book_new/camera_app.php

These are also reasons why I like my 8" Newt (with an MPCC for handling coma) - vignetting not too much of a chore, flat field, FOV about 1 degree, focal length long enough to zoom in a bit but still not too long to make tracking a PITA. This is a very personal choice - you'll hear people haggling about wide field versus focal length. You can't have a beautiful widefield milky way or andromeda shot with doing lots of mosaic work with a long FL, but then neither can you see detail in galaxies or the horsehead with a widefield refractor (without barlows, Powermates etc....). Hopefully this will help you see there is no "ideal" astrophotography rig - its all about choosing the right tool for the flavour of AP you end up preferring (which you don't know till you have a go anyway).

Going 12" and these things all get harder (balance, FL & tracking, OTA/focuser sag, mirror mounting, tighter FOV).

As others have said, you may well be much better off getting started on visual though, and the added aperture benefit of a 10", 12" etc is very significant - something worth checking out by looking through different scopes if you can at all manage it.

[Mountain_Wanderer]

Guys thanks heaps for this info. I think I'm very much decided that my first scope will be either an 8 inch on an EQ5 mount, or a 10 inch collapsible dob. Later, if I want to get into astrophotography, then I'll need a complete new scope and mount and all the other gear, which will take time to work out what to get.

cheers!

[RobF]

Heck, I'm worried now the refractor guys are all going to come after me for saying you can't get in close enough for decent detail.
Disclaimer - above doesn't apply to refractor >$500 for OTA....:D :whistle:

[Mountain_Wanderer]

Hi again. I had a brain melt last night and started thinking that perhaps I should get the 10 inch solid tube dobsonian by Skywatcher. I've done a few measurements and I think it can fit in my tiny car (tube length 113cm, diameter 26cm). Would only just fit though! The weight of the tube on the Skywatcher website is 12.5kg. Interesting because the collapsible version is 15kgs!

So, considering that I begin astronomy with a 10 inch solid tube newtonian dobsonian, and have a lot of fun with visual only and learn the sky etc, then later I get interested in astrophotography, what exactly would be a good equatorial mount to get for this tube? There are mounts around, but would they do a job good enough to do precise tracking, guide eactly and be suitable for excellent long exposure astrophotography? There is a Skywatcher EQ6PRO Synscan Go-To equatorial mount at Andrews for $1,599, or also a Skywatcher NEQ6PRO Synscan Go-To equatorial mount, also for 1,599. Would one of these be suitable and/or what other additions to the mount might I need?

I'm also still trying to get an idea whether 10 inch newtonians seem to be the maximum newtonian size most astrophotographers use for astrophotography. I don't think there's a good common equatorial mount for astrophotography out there for a 12 inch newtonian is there? Is 10 inch considered the size/weight limit, and then most people start looking at refractors or cassegrains?

And just on aperature still, when you compare an 8 inch newtonian to a 10 inch, what REALLY is the difference when it comes to astrophotography? Sure, the 10 inch can show a lot more if you're only ding visual astronomy, but, is the 8 inch pretty well equal to the 10 inch when it comes to long exposure astrophotography? If you are doing a long exposure photo with an 8 inch and want to match the same quality photo that was taken with a 10 inch, then is it only a matter of exposing the photo for longer to catch the same amount of light as the 10 inch? If so, perhaps the 8 inch is just as good?

Oh, and just on the Skywatcher brand. Are these scopes generally good quality or are there much better quality brands out there that we don't hear about? Thinking long term here, am I likely to get a good quality product from Skywatcher that should suffice for the long term? No real dramas with these scopes?

[Screwdriverone]

Jowel,

Don't forget that even if you do buy a 10" dob, you are going to have a 60cm diameter base which is about 40-50cm high which does not disassemble when you have to put it in the car, its not just the tube you have to worry about.

I've said it before and I will say it again: 8" BD200N on HEQ5 Pro.

Perfect balance of visual and AP capability.

With the amount of questions you have in each and every post and how many threads you have started to discuss the SAME topic, I think you need to understand that we can't possibly answer every question you have because the playing field keeps changing from post to post.

Please understand one thing from someone who has been there and done that: You will NEVER find the PERFECT first scope!

We will ALL offer our opinions of what WE like and what WE have experienced, but even if you debate the question until the cows come home, THEORY and speculation of which scope to buy will not replace taking a look through one (or many) at a club meeting or even buying what has been recommended over and over and then accepting that if you spend a smaller amount up front and understand that you WILL end up buying more stuff later, then you will be on the right track to allow yourself to enjoy what you have and enjoy your progression through this wonderful hobby.

I apologise if this is a little harsh, but seriously.....the amount of questions you ask which go ALL the way around the gamut of the choices available and "should I this?" and "what if that?", end up back in the same place and I think just confuses you more.

You will have to start somewhere and in my opinion that is the scope I recommend above.

Of course, if you want (or anyone else wants) to tell me to go jump, then that's fine too.

Cheers

Chris

[OzRob]

There is a similar telescope listed in the classified section. The bonus for you is that it is located in the Blue Mountains.

GSO/Andrews 10" Dobs (http://www.iceinspace.com.au/forum/showthread.php?t=66140)

[Alchemy]

Had a 12 inch on a g11... And it was to the max weight wise, the dob tube itself has too many problems to make it a long term commitment, there are other companies producing 12 inch astrographs newts.... Will blow your budget to bits. So unless you have a loose 15k forget it.

The 10 is workable but I'd prefer a non dob version, or you just may have to beef up the tube around the focuser.

[RobF]

Would be hard to lose much money going with the local dob Ozrob suggested.

[midnight]

Jowel, I remember when I first got my 8" SN on an equatorial mount and I wanted something as big as my budget would go but within weeks, I realised for my skill level at the time, the 8" was an overkill. Yes I was astounded to what I could see but I stopped using it because it was too cumbersome to put in the car (and care for it) and the counterweights on a regular basis.

Even though I now spend a lot of time on it since I got a DSLR as a present recently, the scope really sat idle for some years.:(

In hindsight, a smaller 6"SN or even better a 4" refractor would have got me off to a better start back then.

Just some words from someone who is only in the last year really hitting top gear with my scope and mount which is about 6yrs old.

One more thing to remember, which ever way you decide, you're not going to be dissappointed unless you buy all combinations and set them up at the same time. It's like the old LCD vs Plasma - in the end, it doesn't really matter to 95% of people because once you take it home, you have no other comparison and you'll adapt to your selection.

Enjoy this fantastic science and good luck.:thumbsup:

Cheers,
Darrin...

[Screwdriverone]

Very good point Darrin,

The old adage: "The best scope for you is the one you use the most" holds true.

Chris

[alistairsam]

Hi, I had started a thread for AP with an 8inch reflector and whether its worth changing an F6 to an F4 or F5 for imaging, but thought I'd ask if someone had firsthand experience with both an F4 and F5 8" and could explain pro's and con's of each.
thanks

edit:
on second thought, as I have a home made forkmount, is it worth getting a short focal length 10" mirror? just wanted some opinions on how say an 8" F4 or F5 would compare with a 10" F4 or F5 for imaging with a DSLR. I know there are mount considerations for both, but I've accounted for those. just trying to decide on which mirror to change to.

[RobF]

I'll stick my neck out and say it isn't going to matter between any of those options until you've got 1-2 yrs experience under your belt.

After 12months, you might be starting to consider the following:

- Mount/tracking (likely to be harder with 10" but I have no practical experience)
- Flexure for guidescope mounting/focuser
- Field flattening/coma - tends to be harder and more expensive with larger mirror and shorter Focal ratio
- Quality of mirror - 6" Epsilon Tak likely to blow both all above away anyway I suspect :question:
- Size of secondary
- How well is it collimated
- IMage processing skills (just as hard as getting good data and possibly takes longer to learn)
- Where will you imaging - dark skies best - how portable is it all?
- How easy/hard to put up and down at 2am in the morning?
- What mods do you expect you'll have done in the next 2 years to get the performance you expect (mirror mountings, secondary, focuser, guidescope)
- what do you want to photograph?
- What cameras are you likely to want to use/afford?

Theoretically the exposures from an F4 8" could be 16/25 shorter than the F5 and still capture the same amount of light. I have no experience with an F4 mirror, but know my F5 can "burn out" stars in my current CCD in a few minutes, so I don't really need my rig to be imaging at a faster F ratio.....

More info would be needed on forkmount. Very few people are able to get arcsec guiding out of forkmounts? (happy for someone with experience to correct me....)