I currently have a Saxon 8" F6 Dob. Thinking I could put this on a AZ/EQ6 with my Canon 5D Mkii and start shooting myself some astrophotography.
But I'm sure it can't be quite that simple, right? I mean how do you actually mount the telescope? Do you need another bit of kit? A power supply? And how about polar alignment scopes? Filters? I'm already really stretching my budget. I worry that if I spring for this, there will be a heap of hidden extras that I'm not aware of.
Can anyone pls tell me the hidden 'other' things I'll probably also need to get set up?
you will need a T-ring to connect your camera
rings for the telescope (i assume it is a solid tube not collapsible)
some sort of collimation tool e.g. a laser
eventually you will want an autoguider and guide scope
you will need some sort of battery pack if you want to operate in the field
you wont need filters if you are using a DSLR
software ... there are a lot of good free options but a lot of people use photoshop
those are the only hidden costs i can think of but the big one for me is whether you can achieve focus with your DSLR through that telescope. some dobs are not designed for prime focus photography
Astrophotography IS all about hidden extras !
There is simply no end to the "necessary" upgrades.
To name a few starters . . .
Better mount, better scopes (note plural), field flatteners, screw on filters instead of compression, auto focussing instead of manual, rotation, better cameras (note plural - you'll need different image scales) conversion to LRGB and filters and chilled camera, guidescope and guide camera, cables, power management stuff, USB hub, network hub etc, better software (for image acquisition, fcussing, ASCOM, planetarium control, scheduling, time, stacking, processing, darks management . . .
But once you're hooked everyone of them is completely justifiable as you slide down the slippery slope.
Astrophotography IS all about hidden extras !
There is simply no end to the "necessary" upgrades.
To name a few starters . . .
Better mount, better scopes (note plural), field flatteners, screw on filters instead of compression, auto focussing instead of manual, rotation, better cameras (note plural - you'll need different image scales) conversion to LRGB and filters and chilled camera, guidescope and guide camera, cables, power management stuff, USB hub, network hub etc, better software (for image acquisition, fcussing, ASCOM, planetarium control, scheduling, time, stacking, processing, darks management . . .
But once you're hooked everyone of them is completely justifiable as you slide down the slippery slope.
Good luck with it and enjoy the ride.
Rally
it is amazing how easy it is to forget the extras that you have bought over the years, i completely forgot about a coma corrector, definitely something that is going to be needed in AP. and automatic focussing is a nice but not absolutely necessary. Rally is right though, you will ALWAYS want a little bit better, a little bit sharper and a little bit more resolution, it all comes at a cost. but that is not to say that you cant do fine AP without the majority. most of the things i listed are pretty much essential.
I've been in a very similar boat since I got my first telescope last July, an 8" 1200mm Dob. I've also got some pro full-frame Nikons & pro lenses, and a strong desire to combine the two.
Here's what I've learned through experimentation, chatting in various forums like these, and talking in person to people who've been doing AP for years.
Firstly, you can attach your DSLR to your Dob. All you need is a T-ring adapter; I strongly recommend a Celestron Barlow adapter - they sell them through National Geographic. It's great for planets. I've printed gorgeous high-resolution (ie 20-40MP) shots of the Moon, the Sun (with a solar filter), conjunctions of Jupiter and Venus / the Moon, and even the ISS. I'm quite proud of some of them - they're better than many I've seen for sale.
However, the Dob is simply no good for DSOs, which is where the real action is.
To mount your 8" f/6 tube you'll need a fairly huge mount, like an NEQ6. That mount has a payload of 20kg, meaning it'll hold something that heavy without damaging, but the typical rule is 50-70% of payload for AP. That means with your 11kg tube, camera, rings, finder, guider etc you'd be right at the limit of a NEQ6 (and far beyond the limit of any cheaper mount like the 14kg HEQ5).
Not only that, but I'm told a 1200mm focal length is pretty brutal for a beginner. You're much better off with a shorter focal length to begin with, like 400mm-600mm.
Your options therefore are a small Newtonian OTA, an RC astrograph or a refractor.
The Newts go down to about $400 for a new 6" f/5 (or considerably more for bigger), though you'll then need a coma corrector - essential, non-negotiable - which are around $100-200.
GOOD: cheap, large aperture (shorter exposures)
BAD: tricky to focus and collimate, need CC.
The RCs (Ritchie Chrietens) are still pretty cheap, starting around $700, but they're apparently even harder to collimate, are bigger & heavier, have far longer focal lengths (meaning guiding is essential) and don't have the advantage of the fast focal ratio. These are best left in the hands of the pros, not folks like you and I with no real idea what we're doing.
That leaves refractors. Something small but useable like an 80mm x 400mm will set you back around $4-500, and you don't need anything else beyond the simple camera adapter. They're not much good for observing but they're perfect for AP, particularly beginners.
Myself, I'll be getting a HEQ5 mount as soon as I can afford one, and will simply stick my DSLR with 200mm lens on it whilst I work out how to use a mount, and learn my way around stacking software. Once I've got that under control (and once the hobbies fund is available again) I'll decide between a fast Newtonian (8" f/4) or refractor (ED80).
Oh - and allow me to assure you that simply cranking the ISO on a pro-level camera doesn't work! My camera is pretty much noise-free at ISO 10,000 for well-exposed shots (considerably better than a 5D MkII, a camera I'm very familiar with), but it doesn't work like that when taking pictures of a black sky. The only way to get properly beautiful shots of DSOs is through stacking long low-ISO exposures, which means a good go-to mount is the absolute first stop. Otherwise you're just amplifying noise as the stacking software can't distinguish between low-level noise and very faint stars. You HAVE to use low ISOs, ie 200-400. Shortest exposures you can do is about 30 seconds; ideally you want around 2 mins, depending on what you're imaging.
Hope that helps. Let me know how you go. Keen to hear the experiences of someone else new to the game.
I currently have a Saxon 8" F6 Dob. Thinking I could put this on a AZ/EQ6 with my Canon 5D Mkii and start shooting myself some astrophotography.
The mount should be able to carry your scope. You'll need tube rings and a dovetail to mount your scope. With your camera you'll need a coma corrector and an adaptor (lens removed). To save money I'd get an off axis guider (QHY5 or other, ZWO ASI, etc)
Quote:
Originally Posted by Stonius
But I'm sure it can't be quite that simple, right? I mean how do you actually mount the telescope? Do you need another bit of kit? A power supply? And how about polar alignment scopes? Filters? I'm already really stretching my budget. I worry that if I spring for this, there will be a heap of hidden extras that I'm not aware of.
Can anyone pls tell me the hidden 'other' things I'll probably also need to get set up?
A 12V DC power supply for your mount. Maybe a battery for the field. No need for a polar alignment scope to start with. Don't worry about filters yet.
I've been in a very similar boat since I got my first telescope last July, an 8" 1200mm Dob. I've also got some pro full-frame Nikons & pro lenses, and a strong desire to combine the two.
Here's what I've learned through experimentation, chatting in various forums like these, and talking in person to people who've been doing AP for years.
Firstly, you can attach your DSLR to your Dob. All you need is a T-ring adapter; I strongly recommend a Celestron Barlow adapter - they sell them through National Geographic. It's great for planets. I've printed gorgeous high-resolution (ie 20-40MP) shots of the Moon, the Sun (with a solar filter), conjunctions of Jupiter and Venus / the Moon, and even the ISS. I'm quite proud of some of them - they're better than many I've seen for sale.
However, the Dob is simply no good for DSOs, which is where the real action is.
To mount your 8" f/6 tube you'll need a fairly huge mount, like an NEQ6. That mount has a payload of 20kg, meaning it'll hold something that heavy without damaging, but the typical rule is 50-70% of payload for AP. That means with your 11kg tube, camera, rings, finder, guider etc you'd be right at the limit of a NEQ6 (and far beyond the limit of any cheaper mount like the 14kg HEQ5).
Not only that, but I'm told a 1200mm focal length is pretty brutal for a beginner. You're much better off with a shorter focal length to begin with, like 400mm-600mm.
Your options therefore are a small Newtonian OTA, an RC astrograph or a refractor.
The Newts go down to about $400 for a new 6" f/5 (or considerably more for bigger), though you'll then need a coma corrector - essential, non-negotiable - which are around $100-200.
GOOD: cheap, large aperture (shorter exposures)
BAD: tricky to focus and collimate, need CC.
The RCs (Ritchie Chrietens) are still pretty cheap, starting around $700, but they're apparently even harder to collimate, are bigger & heavier, have far longer focal lengths (meaning guiding is essential) and don't have the advantage of the fast focal ratio. These are best left in the hands of the pros, not folks like you and I with no real idea what we're doing.
That leaves refractors. Something small but useable like an 80mm x 400mm will set you back around $4-500, and you don't need anything else beyond the simple camera adapter. They're not much good for observing but they're perfect for AP, particularly beginners.
Myself, I'll be getting a HEQ5 mount as soon as I can afford one, and will simply stick my DSLR with 200mm lens on it whilst I work out how to use a mount, and learn my way around stacking software. Once I've got that under control (and once the hobbies fund is available again) I'll decide between a fast Newtonian (8" f/4) or refractor (ED80).
Oh - and allow me to assure you that simply cranking the ISO on a pro-level camera doesn't work! My camera is pretty much noise-free at ISO 10,000 for well-exposed shots (considerably better than a 5D MkII, a camera I'm very familiar with), but it doesn't work like that when taking pictures of a black sky. The only way to get properly beautiful shots of DSOs is through stacking long low-ISO exposures, which means a good go-to mount is the absolute first stop. Otherwise you're just amplifying noise as the stacking software can't distinguish between low-level noise and very faint stars. You HAVE to use low ISOs, ie 200-400. Shortest exposures you can do is about 30 seconds; ideally you want around 2 mins, depending on what you're imaging.
Hope that helps. Let me know how you go. Keen to hear the experiences of someone else new to the game.
Very well put Chris - well done.
Though I find my Astronomik CLS filter really does help in light polluted Sydney.
You can fish with a bamboo cane and a bent pin,but you're gonna want a Penn reel and lures and weights anda anadnandnandna
You could go all the way and get a trawler and nets, you will get a good catch and then all you need to do is the processing. But thats not really what fishing is about, if its too easy I don't think that it's as much fun.
Hi Markus, Your 8" dob will ride ok on anything from Heq5 pro and up. You will need tube rings and a dovetail rail (a 12" will give you enough movement to balance the tube). If you use GSO tube rings you might have to pad the rings out a bit as GSO tubes tend to be a bit bigger in diameter than some other brands such as skywatcher.
With this setup and a bit of polar alignment you should be able to get reasonable tracking for 30 -60 seconds. I use an illuminated cross hair eyepice to make adjustments to get the tracking good.
Then you need to mount the camera to the focuser, a t-ring and mount.
Seeing that your scope is an f6 a coma corrector is not essential, and collimation not as critical. If you can get the camera to reach focus then you are good to go. The only other problem you will probaby encounter is vignetting, ie the seconday mirror on your scope is too small to fully illuminate the sensor on your full frame camera. Your image will be darker around the corners.
You don't need a lot of fancy add ons to get started, it just makes the job easier to the ultimate point where you pick your target for the night turn on the equipment then go inside and watch a bit of telly and all you have to do is proccess the data.
Here's a link to my 10" dob astrophotography conversion project. http://www.iceinspace.com.au/forum/s...d.php?t=125986
Thought I'd add a few of my own 8" Dob images now that I'm on a real computer. These were all taken with a full-frame Nikon through a Celestron 2x Barlow T-adapter. They're all much lower resolution versions of the original files.
But seriously - if you're going after DSOs and serious astrophotography, your 8" f/6 falls squarely into the way-too-hard basket for a beginner. Instead of spending $2k on a mount that can handle it, and rendering your Dob mount useless (unless you have a gigantic mount you'll have to take off the Dob's mounting pegs), you're far better off spending that $2k on a smaller mount and a refractor and avoid immense frustration. Keep the Dob for easy observing. I've been given this advice by literally dozens of people who were extremely keen to save me from months of headaches and wasted nights. Many of them arrived at this conclusion after having had the exact same thought process as you (and me).
Or hey, do what you plan to do, get that huge thing on a mount, and let me know how you go - maybe all the people I talked to were overly pessimistic. Doppler's images below are pretty impressive I must say, though he's using a much sturdier pier mount - not a tripod - and has a larger aperture which allows for shorter exposures. And he also seems to really know what he's doing with regards to alignment and tracking.
Wow, such a lot of detailed responses - thanks so much guys! I haven't replied until now because all your detailed replies gave me pause to sit and have a think about what I really want to get out of it.
I have to admit, I've messed around with some photography already - going about it all the wrong way in full knowledge of that fact - using my dob. It's not even a goto, LOL! I'll post some pics if I can figure it out.
And here's what it comes down to for me. I like seeing more detail and colours that I couldn't on the night itself. Planets are great. The moon never really interested me all that much, but DSO's have always been the thing that I'd like to *properly explore.
Now I know we've been spoiled by Hubble, (the satellite, not the man, though I'm sure he was generous in his own way) and nothing you see through a telescope will ever compare, but if I want to see proper detail in some of these more elusive objects, or even some of these objects that are supposedly there, but just won't show up in my eyepiece (or just turn up as small fuzzy patch that can only be seen *maybe with averted vision'), I really have two choices.
Get a bigger Dob to tease that detail out for visual observing, or get into astrophotography. Seriously, I can't tell you how fun it was capturing those simple images, and post processing was a part I really enjoyed too. I'm not much of an engineer though. It could be frustrating figuring out if the problem was a bolt not being tight enough, or wind, or motor lag, undervoltage, bad polar alignment shutter vibration, etc etc. On the other hand, I'm not looking for too much more than what I'm getting through my un-guided Dob.
Doppler posted some great pictures in his 10: Dob project. How long does it take to get to that level? How many objects can you photograph in one evening? Is 5-6 pushing it?
Otherwise I guess I'd better get me to a star-party and have a look through some bigger (10-12"?) dobs and see if they really do make that much of a difference. I'm also thinking that maybe I should see how much of a difference better eyepieces and maybe some filters can make to my current setup.
I should add, that I tend to drive to a dark sky site about 80min from Melbourne. It's pretty good - just on level 3 on the light pollution map (goes all the way up to 13 in the CBD), which is pretty good, I figure.
And here are the pics. Some are with my DSLR. Some are prime focus throgh the 8" F6 Dob. Obviously there is trailing, but considering it's not even a go-to or anything I was very happy just to get that!
OK, so here is the good news. You don't have to have a big aperture to get those same pix. In fact you are better off with the suggested ED80 or slightly bigger and all the incumbent guiding gear etc and just taking longer exposures.
I'm using a LUNT 102mm ED F7 refractor and seemed to have finally cracked the alignment\guiding problems and getting better results with no trailing. It is sitting on an EQ6 but only because that was available when I was buying. My 10" Dob which I modified to be able to work on the EQ6 is back on it's DOB base and is unlikely to ever be remounted. The current setup is working well.
So would I be correct in guessing that the reason you suggest starting lightweight with longer exposures because the more weight you have, the more it compounds any issues you might have?
So why is it not the reverse? If the shutter is open for longer on a smaller scope isn't that more time in which a problem can exhibit itself?
What sort of aligning/guiding issues have you had to struggle with? By that I mean - was it a matter of practicing a skill until you mastered it (something I have more confidence with) or is it more a matter of playing engineer and chasing your tail to diagnose and eliminate all the possible causes of a fault that can only really be diagnosed by swapping parts out one by one (I used to do this sort of thing for a job and found it really frustrating).
Cheers Markus
Quote:
Originally Posted by ZeroID
I'm using a LUNT 102mm ED F7 refractor and seemed to have finally cracked the alignment\guiding problems and getting better results with no trailing. [...]
My 10" Dob which I modified to be able to work on the EQ6 is back on it's DOB base and is unlikely to ever be remounted. The current setup is working well.
But some beginers are are on a small or like me non existant astro budget and have to make do with what we have at hand. So you add all that guiding gear, ed scope and goto mount up and even second hand it comes to a couple of $1000.
I think that the point here is that you can get some ok images with basic equipment and new digital camera's, before you have to succumb to the urge to upgrade. Personally I like to take some pics for fun but don't have the time or money to try and get Hubble quality pics.
The pics I can now manage to take with a 30+ year old ra drive only mount used to be impossible with a 35mm film camera but with a dslr..... easy as.
But the dark side has subtle powers, after 30 years with a RA drive only pier mount, I now have a Heq5 goto to play with. All good fun, but I wish the weather would play nice as well.
Oh dear. Judging by those pics you posted you've already gone a long way to the "dark side"
You CAN do astrophotography with your 8". As others have said, down that road you'll encounter challenges and costs such as:
- Need rings and mount (HEQ5Pro can do what you want EQ6/NEQ6/AltAzEQ6 better)
- Probably need coma corrector, may not initially
- Likely need guidescope and guide camera to get >1min pics
- Will need access to dark sky site, but can do lots from suburbia too
- Will need laptop for guiding, camera control eventually then camera/guiding control software as get serious
- Likely to want to buy processing software
- Auto-focus is a huge boon, but again, has costs
- Can't do visual while using your dob for AP
- Will lose lots of subs to guiding issues and have to be really patient re focus etc
So for a newt system, perhaps:
$1600 HEQ5Pro
$100 Rings
$600 Guiding package and camera, dovetail, rings (less if used a 50mm finder/guider)
$1000 Laptop
Alternatively, for an ED80 setup, you probably will have backfocus for an off-axis guider but have the extra cost of an additional OTA. LOTS easier to guide at the smaller focal length.
One big benefit of the 8" is its light sucking power, so subs don't have to be as long.
