Astrophotography Rig Advice

[tvandoore (Tim)]

That's the most spectacular thread hijack I've ever seen.

Having said that, the analogy of telescopes = shoes is most constructive and should be discussed further.

[Outcast (Carlton)]

Thanks Markus,

Some good considerations there. I have an f10 SCT which does reasonably well on the planetary & lunar front, sure, Az/alt mount but, adequate for collecting video sequences for stacking.

I'm about to acquire my first Newts in one of Alex's exquisite Gondwana Dobs (12" Marana) so that will be my first foray into collimating Newts.

I'm definitely leaning towards the APO although, to be
honest, it is some way off on the purchase horison as I have a learning path mapped out in the form of learn how to setup my EQ mount, use my DSLR & lens to track & improve my mount setup & tracking progress, move to my little 80mm Achro & continue to refine my setup, alignments & tracking...on top of all this there is the learning curve on processing..

Then later comes the transition to guiding & more to learn...

Progress to anything better, mount or scope will be some time off, this was more about kicking telescope tyres & hearing what more experienced folk had to say & it's certainly achieved that...

Cheers

Originally Posted by Stonius

+1 for 100mm APO. Contrary to popular belief, you do need to check their collimation, but once set, they hold it much better than any of the reflectors you mention.

I'd steer well away from a small RC. They require a bit more fiddling to get right and I understand collimation is trickier the smaller the aperture.

Essentially it breaks down like this;

If you want to capture nebulae, you'll get a lot of instant gratification with a 100mm APO. Lots of detail and an image scale that will a) fit larger nebulae in, like n Carinae, M42 and Running man, the entire Rosetta (depending on pixel size, of course) and b) be more tolerant of tracking errors if you don't have the $$ to pay for the mount.

If you want Planetary, the mount becomes even less important because tracking just has to keep the object in frame for a few minutes. But! You'll need longer focal lengths - typically achieved by a combination of powermates and native scope length. You want around 5-6000mm total focal length to get surface detail. A lot of it comes from the seeing. After that it comes from getting lucky breaks in the seeing that last fractions of a second, so you'll want a fast shutter speed. More aperture will give you more light to play with and therefore faster shutter speeds, so a Newtonian may be your best bet here.

But if you really want galaxies (other than Andromeda, M33 and the Magellanic clouds) then I'm afraid there is no help for you. You really need a good mount - there's no getting around it - because you need excellent tracking at long focal lengths. I would spend all your money on a decent mount and just get a non-APO to play with fo the time being. If you have a mono camera with a filterwheel, shooting RGB will ameliorate chromatic aberration somewhat, but to get to those kind of focal lengths with a small aperture instrument will be way *slow. For example, doubling the focal length of a system *quadruples the exposure times. You may get more joy with a newtonian in this situation.

But yes, I'd definitely avoid an RC scope (I have one). They are good scopes and remarkably aberration free, but you'd want to feel very comfortable collimating a newtonian before considering one, and even then the design practically requires a Tak collimating scope to get to star-test stage.

Hope that helps you some :-)

Markus

[Outcast (Carlton)]

Ya know Chris,

It's funny, I once lusted after one of these.. then I got to play one (albeit briefly) & honestly... I wasn't that sold on it...

I have a MIJ 30+yr old Fender PJ which plays like a dream & has just a fantastic tonal range due to the PJ setup & blend function..

I also own a $400 Made in Asia Musicman Subray & it just kicks ass... down right dirty, gritty, angry snarl of a bass...

I certainly want more basses, hell, who wouldn't but, these days I don't dismiss anything til I play it.. there is some real gold out there for insanely cheap prices.. ya just gotta find em...

Cheers

Originally Posted by ChrisV

Carlton

There is only bass. To rule them all - the rickenbacker 4001(3).

Chris

[Outcast (Carlton)]

Dunk,

My wife is a shoeaholic... but, I've tried that argument & all she does is come back at me with a price comparison.....

Having said that though, she's pretty good & I am beginning to amass quite a collection...

I have a couple of camera options at present, DSLR, ZWO ASI224MC & I've managed to acquire an Orion SSAG & get it to work for image capture in Sharpcap (albeit a bit clunky for gain adjustment)... & will later be used for guiding.

I'm getting my head around the strengths & weaknesses of each of these camera's as part of my learning journey which, will likely then inform a better imageing device in the future.

Cheers

Originally Posted by Camelopardalis

Just to echo a few sentiments...

It’s your hobby, your money, your time, your image, your enjoyment

Some folk like the competition, the thrill of the chase, whatever it is, get in touch with your goals and reach for the stars

Sorry, a bit philosophical for this time of the morning

Another analogy is, especially for the Mrs, is that telescopes are like shoes...you don’t wear hiking boots the ballet nor do you wear stilletos to hike a mountain

An SCT, a mid-size newt and a small(ish) refractor cover a lot of bases and should keep you busy for a while. Each has their own strengths, and weaknesses.

Just remember that the scope is just one side of the equation. The photon receiver is the other side. Visual or camera. This camera or that camera. Cameras have different characteristics, sensor size, pixel size, QE, noise, cooling or not...similarly, all have their uses. A combinatorial approach gives you more options...and cameras are more invisible than telescopes

[Camelopardalis (Dunk)]

Carlton, for planetary with your SCT, the 224 will be streets ahead of anything else. Only the 290 comes close. It’s just the most sensitive to date.

DSLR must be tricky up there with the noise, it’s bad enough down here for half the year I ended up buying a cooled camera and it works well. There are plenty of options...

Best thing I can suggest is get to grips with your gear and get some images you’re happy with before splashing out on too many toys. Especially when it comes to the cameras, the technology is changing all the time and it doesn’t make sense to buy one you’re not ready to make full use of.

[Outcast (Carlton)]

Hi Dunk,

What you have said is exactly why I purchased the 224MC; I did a lot of research before I purchased this camera & like you have stated found it to be very good in terms of both sensitivity & noise levels.

Amusingly, I haven't actually used it that much for planetary work since I got it; between weather (our wet season) & shift working during the dry season, my opportunities for any astronomy have been extremely limited. I have however, managed to use it to provide live views of some DSO's on a tablet & played around with some DSO captures... a DSO camera it is not but, then again, it's not bad when you take into account it's limitations & use it accordingly.

Noise certainly is an issue up here; sensor temperature on the ZWO is routinely up around 35 degrees or more on the ZWO & I have no idea what the temp is on the DSLR. I'm toying with the idea of a heat sink & fan setup on the ZWO to drop the temp a little; I don't want to go the Peltier route as dew point here is usually high & it will induce moisture buildup.

With the DSLR, I need to investigate turning off some internal functions that aren't required to try & minimise heat buildup as much as possible.

Fortunately, to some extent the noise issue can be ameliorated in post processing together with darks & flats; again, something I am only just beginning to experiment with.

Whilst a purpose built cooled camera would be nice, it's not on my agenda for a long time (if ever, in fact) partly because of cost & partly because I think I will be able to achieve acceptable results with what I have.

As you say, best thing is to get to grips with what I have & push them to the limit before determining whether something else is needed or, I have reached the point of personal satisfaction with the outcomes. I have my plan of attack... it involves the KISS principal & moving ahead one step at a time, only when I have become competent in the previous step. First in line is getting my head around the EQ mount I just acquired; it's not the greatest mount ever but, it was very cheap (2nd hand) & will keep me happy for sometime to come I suspect.

The next purchase will likely be an 80mm APO but, not solely for AP; we have some travel plans that involve flying which makes taking the SCT or my next acquisition (a Gondwana Marana 12" dob} impractical. My decision on purchasing an APO will come down to how my little Orion 80mm ST performs both visually & for basic AP (I know it will have issues but, they may be acceptable in the short term), I also am thinking about something like the Sky Adventurer mount to combine with a decent photo tripod, again for air travel but, if I decide to only go with visual, then one of the cheap handraulic mounts I currently own will suffice for my immediate needs.

Cheers

Originally Posted by Camelopardalis

Carlton, for planetary with your SCT, the 224 will be streets ahead of anything else. Only the 290 comes close. It’s just the most sensitive to date.

DSLR must be tricky up there with the noise, it’s bad enough down here for half the year I ended up buying a cooled camera and it works well. There are plenty of options...

Best thing I can suggest is get to grips with your gear and get some images you’re happy with before splashing out on too many toys. Especially when it comes to the cameras, the technology is changing all the time and it doesn’t make sense to buy one you’re not ready to make full use of.

[Camelopardalis (Dunk)]

Planetary season will come around soon enough

I wouldn’t bother trying to cool the 224 unless you intend to use it for long exposures. For lunar/planetary, the exposure times are so short that the accumulation of thermal current is negligible.