Last year I bought a 10 inch Saxon dobsonian telescope with a cheap third party base. My aim is eventually to do astrophotography, and I know that for deep space photography dobs aren't great. I'd like to gradually move towards this - ideally by buying an eq mount first and then motorised it at a later date. I know this is an area where people make mistakes and waste thousands, so I'd rather do it right!
My scope weighs 12.5kg without the base. Am I right in thinking an eq5 would do the job, or would I need an eq6? Are there any others worth looking into? Most importantly, will I be able to motorise these after the fact with enough accuracy for deep space photography?
I'm hoping that a few people on here have done this before, and can give me a few pointers
I think EQ5 is not adequate for this load. Once you have everything else needed for AP (camera, finder, tube couterweights, tracking..) you will be over 18-20kg on one side of the mount in no time.
I am currently working on my 10", OTA with optics only has 15kg (fiber glass) and EQ6 is *just* good enough to carry all that.
I am even thinking about EQ8 for all this....
eq5 won't do the job -even a heq5 would be pushing it with the length of tube/weight, eq6 is it -most now come with built in synscan -ot sure if you can still buy the manual versions of these mounts
Don't do it. You will need an NEQ6 at least as previous posts have pointed out. My 10" custom carbon fibre strut imaging newt weighs 13kg without guidescope, finderscope, camera, etc. and with these things the total imaging load is just over 15kg. The published imaging capacity of the NEQ6 is really about 18kg but lower is always better, especially on a tripod.
If you really want to get into imaging at 10" then sell your dob and make the investment in a capable mount for the size scope you want to run. You might be able to run a 8" newt on an HEQ5 but I am not sure how much your peripherals would add.
In matching scopes to mounts, I have tried to maintain a total weight that does not exceed 2/3 of the rated capacity of the mount. There's no science to this, just a rule of prudence I have applied in the past. With high-end mounts, you could probably go higher but my belief is that you stress the system in many ways that are not immediately apparent.
So, I add my voice to those of others here and say don't go down the HEQ5 route if this is your scope of choice.
I would add that a visual scope, like your dob, may not be well suited to imaging. The position of the focuser is designed to match the visual user. An imager would very likely want more backfocus to accommodate a MPCC and camera. This means you may well struggle to bring a camera to focus without making some serious adjustments to either the position of the primary (i.e. pushing it a bit further up the tube), or the focuser.
Thanks for all the input! I had a look at an imaging rig on Friday night and realised just how out of my depth I would be upgrading my current set up to it, and how much it would cost. The observatory actually rent out the scope for astrophotography at $100 a night, so that's probably going to be a better option. In the meantime I'll get an official saxon base for my dob and use it as nature intended.
I was recently in your position. I got a bargain 10" dob, the views were fantastic from my light polluted home. But I was getting sick of only being able to take 1 second exposures. I was thinking of making an heavy duty GEM (I am a engineer with a full workshop), Then I bought a complete imaging set up off this site for quite cheap, and realised how hard it would have been to do myself. There are so many little things to imaging that I didnt know, so its best to start small. I got a 127mm refractor and good mount, the pictures are far beyond what I imagined was possible, and I reckon that it will take me ages to master it.
So my advice is, you made a good choice, keep the big dob for visual, and keep your eye out for a good mount and smaller scope for imaging.
Hi Graeme,
Like you I have a Saxon 10"dob which I have converted to a split-ring or horseshoe EQ mount. I've made the secondary section adjustable for astrophotography/viewing. It's nearly completed with some final touch-ups and adjustments.
You can see this on "current project" thread in the ATM and DIY section. I hope you can get a few ideas from the information.
Cheers!
Hi Graham,
I converted my 10" skywatcher dob to eq last year. http://www.iceinspace.com.au/forum/s...d.php?t=125986
The 10" is great for imaging but does require a strong mount to handle the weight. I tried my setup on an HEQ5 mount last week but I think the weight was a bit much for the tripod legs, and good balance is critical to avoid stress on the drive motors. My next plan is to make an adapter for my portable pier, should make it much lower and more stable.
At a minimum, you'd want a EQ6 (remember you need to add guider/scope camera as well).
Having a pier setup helps as the tripod is not quite up to the task for long exposures IMHO.
Bo
