Piecing together an imaging setup

[MarkOw]

Hi,

Looking for some advice on getting a DSO imaging setup going. I'm really a visual astronomer - CPC800 is my main telescope - but I've been dabbling for a few years with a Canon 600D (unmodded), Sky adventurer and a few basic lenses, but now trying to have a proper go at dso imaiging.

I have acquired an HEQ-5 Pro mount (with belt mod), so have an EQ mount ready to go, but no scope for it yet. I'm thinking I probably want to go for a skywatcher 72 or 80ED from reading the forums.

Finally, I like tinkering, and making small upgrades bit by bit, and love to re-use second hand kit and feel I'm getting a lot for the money rather than buying everything new - but I'm also aware that a sub-standard setup could just get poor images and put me off for good.

So, my question is: what is the minimum set of equipment I need from here - can I use my unmodded DSLR, or do I need mono camreas / filters to get anything good from a suburban location?; do I have to have a guide scope and guiding camera or can I add this later?; do I need an autofocuser or should I be able to do well enough manually to start with? 

Thanks in advance for the advice!

Mark.

[Elp]

I'd just try with the camera body and lens first. Depending on how good the internal tracking of the mount works will determine when you'd need to start implementing autoguiding.

One of the best pieces of imaging equipment I've used isn't in fact a telescope, it's the Samyang 135mm F2 lens (imaging at this focal length will need autoguiding).

 

[MarkOw]

Yes, I was thinking of starting out just with lenses as an alternative.

I've looked at the Samyang 135mm a few times but figured it was the same price as a Skywatcher... until I started realising I needed flatteners, T-rings, extesnion tubes.... so maybe I should go back to that idea!

Thanks

[Elp]

If you get into it it'll be a sinkhole for your finances. What you want to image also has a bearing on the equipment you'll use as very rarely does one do all "well". That's why the suggestion to use your camera as is for now, and get practice in with regard to the fundamentals like polar aligning, focusing, finding and framing targets etc. 

To answer some of your other queries:

can I use my unmodded DSLR - yes though on emission nebula it'll be hampered a little as the in built IR filter tends to block out hydrogen alpha signal or allows very little through

do I need mono camreas / filters to get anything good from a suburban location? - not necessarily but a colour/OSC narrowband filter can help where LP is present on emission targets rich in hydrogen alpha and oxygen3. A mono setup will help greatly as you can image ha/o3/S2 "through" LP and even during full moons (o3 will however get affected if the moons nearby to your target). Filters will be an added cost, sometimes more than the camera if you want good ones. Broadband "true" colour (OSC) imaging, the general consensus is to not use any LP filter as it partially blocks the faint signal you're trying to capture in the first place, your ability to image OSC well is largely dictated by your immediate and surrounding LP (for me it's very difficult).

do I have to have a guide scope and guiding camera or can I add this later? - needed beyond a certain focal length depending on your per image exposure duration. Theoretically any focal length can image say sub 1s, but increase that to 10s or more and it becomes harder to impossible. You don't need one to start off with, use the mounts in built sidereal rate.

do I need an autofocuser or should I be able to do well enough manually to start with - I've been doing it 4 years or so, never seen the need for one, it's an unnecessary expense. Learn what you can manually first as you'll get a better understanding of what you need and what you don't.

What lenses do you have currently as most don't do astro very well at all. For wide the Samyang 14mm ED is very good but you'll struggle to use it in an urban setting or if stray light sources are around due to the curvature of the lens. A good 50mm makes for nice semi wide field too. The SY135 targets a lot of the favourites very well, if you're patient you can find them used at decent prices (not more than 300), people complain about the quality of them, I've had a few and they were all acceptable to me.

Edited April 20 by Elp

[MarkOw]

Thanks - lots of helpful thoughts. Glad to hear I don't have to have *everything* to get started! 

I'll try the DSLR as it is to start with and unguided until I get the basics sorted.

I spotted an old William Optics Z70 with flattener for sale that looked like it was in good condition - seems like a good alternative to the Samyang if similar price? 

 

[Elp]

If it's the Zenithstar you're referring to, they are quite good, I've got the Z61 myself.

[ollypenrice]

Be aware that dedicated CCD cameras are now considered old school next to new CMOS cameras and represent stunning value on the used market.

Autoguiding is one of the great triumphs of amateur astrophotography, turning a mount like yours into a premium performer. Don't be put off by guiding, rejoice because it's there!

Olly

[MarkOw]

oh no, now I'm off looking at guidescopes and cameras again... arrghhh. Oh well, I'm going to take my time and enjoy the journey, that seems to be the main requirement (along with lots of spare cash!)

I made the mistake of getting a RaspberryPi set up with Stellarmate a few weeks ago, which has the tools for all these extra gadgets. But at some point I have to stop messing around with trying to get all the equipment together and actually take some images!

Thanks for all the input, it has helped.

[Elp]

If you want to setup autoguiding right now it's minimal outlay, a small 30mm guidescope is around 50 (svbony one) and the guidecam maybe 100 if you buy used.

But as I say, use what you have, if you're imaging with a short FL lens you might find your mounts tracking good enough for a start. Getting the computer controller involved now you'll be faffing about with technical issues and likely some element of problem solving. Learn to polar align first if you don't know it already, focusing, making sure your objects are centred and get some imaging running though the camera. Adding autoguiding after that will be fairly straightforward.

[carastro]

Autofocusser is not necessary, I have never used one.  But some people like to automate everything.  You can certainly do without one until such time as you feel you would like one.  

As a personal choice, I like the features of the Skywatcher telescopes such as the mounting rings and fitted finder which you can convert to a finder guider. 

WO scopes have stunning optics, but you cannot mount other stuff on it if you want to (dual rig for instance) or mount a finderscope without a bit of DIY.  I had a WO scope, and it was supposed to rotate (if you wanted to rotate the FOV), but it only seemed to rotate when there was no camera inserted, which wasn't much help.    Also on my particular WO scope (WOZS71) you had 2 screws to hold the camera in place which inevitably caused a bit of flop and tilt.  There was no way to attach a "screw in" focal reducer, though I think some WO models might be different.   In the end I swapped my WO scope for another Skywatcher (for my dual rig).  Just my experience.

You can image without guiding to start with, but you won't be able to do very long exposures without star trailing and therefore won't pick up much detail.  You will soon see when you need a guide scope by length of your subs and shapes of your stars.  But you can certainly get started without guiding.  

I agree with Olly, a second hand CCD camera might be a good option, though I cry when I think of the prices they sell for now having several CCD cameras myself. 

Carole 

 

 

 

[Elp]

8 hours ago, carastro said:

WO scopes have stunning optics, but you cannot mount other stuff on it if you want to (dual rig for instance) or mount a finderscope without a bit of DIY

It would depend on the scope package. My Z61 by default I think only had the one finder shoe. I bought a few from China as they're useful to have around and very cheap, now I have two right next to the focuser (one for guidescope and one for asiair for example). I changed the default camera type "lens" mount to the Cat handle and rings and how have a third centrally mounted accessory shoe which better helps with balancing of the load with the GS centrally mounted. So yes, extra expenses but not really different from certain other brands out there.

The Z61 has a 1.25/2 inch visual back which is compression ring fitted. You can screw that assembly off and are left with an m54 I believe female thread to screw the flattener into with the flattener itself terminating in an m48 male thread. The flattener has a built in rotator.

Other scopes in the range may be built different.

Edited April 22 by Elp

[MarkOw]

12 hours ago, Elp said:

The Z61 has a 1.25/2 inch visual back which is compression ring fitted. You can screw that assembly off and are left with an m54 I believe female thread to screw the flattener into with the flattener itself terminating in an m48 male thread. The flattener has a built in rotator.

This is my other fear - getting an OTA and then finding I need a long list of adaptors to get my DSLR connected and to the right focal plane. Is there a simple rule of thumb to use with scopes to make sure this doesn't happen, or do you need to understand the specifics of each OTA and therefore in reality you just have to do this once you have the scope in your posession. 

I do have the connectors to get my DSLR onto my C8, so I guess some of that might help - although it is all 1.25" and I'm guessing I'll need 2" connectors.

[MarkOw]

20 hours ago, carastro said:

WO scopes have stunning optics, but you cannot mount other stuff on it if you want to (dual rig for instance) or mount a finderscope without a bit of DIY.  I had a WO scope, and it was supposed to rotate (if you wanted to rotate the FOV), but it only seemed to rotate when there was no camera inserted, which wasn't much help.    Also on my particular WO scope (WOZS71) you had 2 screws to hold the camera in place which inevitably caused a bit of flop and tilt.  There was no way to attach a "screw in" focal reducer, though I think some WO models might be different.   In the end I swapped my WO scope for another Skywatcher (for my dual rig).  Just my experience.

Thanks Carole, this is the sort of thing you'd never know reading all the specs! I'll stick with a Skywatcher to start with then, it does seem that everyone on here has used one at some point and even if they've moved onto something else they still seem to keep the SW as well which must be saying something.

[Elp]

If you want a flat field across the FOV of your sensor you need to use a flattener or a flattener-reducer with a refractor that doesn't have one built in, this will be more so the case with a DSLR sized sensor (typically apsc size). Backfocus is easy with a DSLR body, you just need a t ring which makes up 11mm thickness to add to the typical dslr body front of camera to sensor distance of 44mm (11+44 = 55mm) which is the typical backfocus distance of most flatteners. Just check the spec of any potential purchase first.

With any sort of AP imaging it's always useful to have at hand sets of standardised (whether you decide on m48 or m42) adaptors, spacers and connecting adaptors so you don't fall short at any time. I've standardised to m42, but it still means I need m42 to m48 adaptors to connect to flatteners, filter drawers etc, across my refractors or sct, also used them with my Newtonian when I had one.

Edited April 22 by Elp

[MarkOw]

Ah, ok, that’s very useful, I was wondering how to calculate the focus position and what adaptors I needed. This makes it a lot clearer. 
I have an 11mm T-ring adaptor already for attaching DSLR to my C8, so I guess I can re-use that with a few additional extenders to make the focusing work. 
This is all starting to make a bit more sense, so thanks!

[TiffsAndAstro]

3 hours ago, MarkOw said:

Ah, ok, that’s very useful, I was wondering how to calculate the focus position and what adaptors I needed. This makes it a lot clearer. 
I have an 11mm T-ring adaptor already for attaching DSLR to my C8, so I guess I can re-use that with a few additional extenders to make the focusing work. 
This is all starting to make a bit more sense, so thanks!

I have an unmodded 600d with a sw 72ed and flattener.

I linked couple of images taken with it below to give you an idea of it's potential. I'm certain I can get better results if I increase my total integration time for these 1 to 2 hours to 10+ and get better processing skills.

At Xmas I had  camera + tripod, then added mount, then Nina, then got main scope and guide cam. everything I *need" to image, but not everything I'd like

 

 

Edited April 27 by TiffsAndAstro

[MarkOw]

18 hours ago, TiffsAndAstro said:

I have an unmodded 600d with a sw 72ed and flattener.

I linked couple of images taken with it below to give you an idea of it's potential. I'm certain I can get better results if I increase my total integration time for these 1 to 2 hours to 10+ and get better processing skills.

At Xmas I had  camera + tripod, then added mount, then Nina, then got main scope and guide cam. everything I *need" to image, but not everything I'd like

 

Great to see some images from a setup similar to what I’m hoping to get to.  These are great - I’d be very happy to get these results!