What to look for in a telescope for astrophotography?
Hey guys,
I am still thinking about which telescope to purchase and along with those thoughts I have started thinking about astrophotography.
Now I know it's not easy to photograph the heavens, but I would like to have the option of trying to as long as I have the right equipment.
I know a LARGE aperture means the telescope is better for DSO's but I just have a question in regards to the two telescopes I'm looking at.
Its basically between the Andrews MC150x1900 Maksutov-Cassegrain and the ED80 x 600 with AZ3. Naturally a beginner like me would think it's better to go for the AndrewsMC150x1900 Maksutov-Cassegrain due the larger aperture.
Am I right in saying the Mak is better for photography because of it's greater aperture or is the ED80 a better scope with regards to it's "EXTRA-LOW DISPERSION". I read about the ED80 in one of the other posts and it's within my budget.
For my last question, what do people generally look for in a digital camera for astrophotography? I have a FinePix S6500 fd.
Nup, for a beginner, aperture is not essential for astrophotography, just expose longer with a smaller aperture. Your heading for grief with a 1900mm FL OTA to start with, youd need to spend serious money on a mount 1st. The ED80 will give you awesome results with a cheaper mount.
ummm, from a quick scan of the FinePix S6500 fd spec, it appears it has a fixed lens, IF thats the case, its a dud for Astrophotography, you need to get a Canon DSLR. Sorry, you really cant fit this cam to a scope if you cant remove the lens.
The second number is the focal length of the telescope. All other things being equal, an 80x600mm scope will have 50% more of a field of view than an 80x900mm scope, and 2/3 the magnification. However, it will require significantly less time to take a picture due to the "faster" optics in this example of f/7.5 vs f/11.25. Faster (lower) is better for a focal ratio.
Another thing to look for in a scope is a decent focuser if you have the budget. This can be picked up as an upgrade, I would recommend the 10:1 crayford style which will give you much more precise focus control.
The ED80 probably wins for photos but to look through and see deep sky objects aperture wins. Depends how much the scope is for imaging or for looking through.
I just had a look online at a store here in melb. This scope (SkyWatcher 102mm Maksutov-Cassegrain Telescope) is going for $699 with EQ2.
F/L: 1300. Focal Ratio: 12.7.
Would this scope be better than an ED80?
In its description it advises this scope can be used for astrophotography.
Thanks heaps guys for all ur info, it is helping!
Scopes with long focal lengths are much more difficult to achieve accurate tracking and certainly would not be considered as beginner imaging scopes. 1300mm isn't very long but at f12.7 it will not collect much light onto your photo sensor and make exposure times very long for deepsky objects. I would have thought that the ED80 would be a better imaging scope. It is however a much longer scope physically and probably a bit harder to carry around than the little mak.
Visually the mak will collect more light than the ED80 and you would see more through it. However for about the same price you could get a 200mm dob and see much more.
Hi Frosty, Here is my two bobs worth.
Essential items for Astrophotography are:
First an accurate EQ mount which is capable of accurate tracking and active controlled guiding. Without these abilities you will really struggle to get images with any scope.
Secondly you will need a telescope. The higher the focal ratio the higher the magnification you will end up with after fitting a camera. Most DSO objects are infact quite faint even in large appature scopes but digital camera systems gather and store a lot more light than our eyes can so with slightly larger exposures can and do show up DSO's quite well.
Some of the DSO's are also quite large and require the lower magnification of smaller Focal ratio telescopes. I would sugest the ED80 would be the best scope for astro imaging out of your two choices.
I have a couple of images attached which will shine some light on the difference between low and high focal ratios in Astro images.
Both images are of Omega Centauri taken with a Tak FS102 refractor using a Canon 40D Digital SLR camera with the same exposure times.
The first is taken at the scopes native Focal ratio of F8 and exposed at ISO 800. The second is taken with a 2X barlow lens fitted between the camera and the scope. This has doubled the magnification and increased the focal ratio to approx F16. This image was exposed at ISO 1600 to get a usable image. The first image can be software magnified to show more detail but I am sure you will be able to see the difference between images from a noice and clarity point of view.
Focus is also a lot easier with the smaller foal ratio telescope.
Thanks for all the advise guys. I will be going telescope browsing/shopping in the next couple days and actually have my eye set on the ED80.
I have found the scope for $499 @ Andrews Communications.
I also found the same scope at myastroshop.com.au for $595.
Assuming Andrews is selling the exact same scope than myastroshop.com.au then I will be getting it from Andrews.
The other thing I am looking at, is which mount to buy for the ED80. If the scope itself is gonna cost me $499,how much would a reasonably good mount cost?
Andrews is also selling the scope with an AZ3 mount for $650. Though I have been advised that mount isn't very good for that scope. So I will need to look into it.
Can anyone recommend a good mount for the ED80 with the price.
i have teh skywatcher ED80 and it is a fantastic scope, i wouldn't ask for much more for doing astrophotography. the view is amazing clear, crisp and extremely sharp, easily the best bit of glass i own for my cameras. so a good choice withe scope.
i personally have the skywatcher HEQ5 mount, which is a fantastic mount, but in hindesight i prolly should have got a goto system with my mount. but that is not necessary.
as for your mount, you will most likely be wanting nothing lower than an EQ4 mount. however, you do have to think of the future, if you reckon you'll go with a bigger scope down teh track sometime, you may be wise to look at the HEQ5, which will mount a 6" newt no problems, and possibly upto an 8", if my sources are correct.
The mount should be your prime requisite if you wish to use it for astrophotography. I would not buy anything less than an EQ5 with motor drives. I have both an EQ6 and HEQ5 with Goto on both and find the EQ6 to be by far the best out of the two. It is larger, has a better load carrying capacity and generally seems more robust and better suited to the job. Both are quite a lot more than you are indicating above but either willserve you well and allow for your telescopes growth a little.
You mean something like this? EQ4/EQ5 dual axis motor drive kit - includes hand controller $199.00
Is this more expensive than a standard RA drive because it's dual axis?
I tell ya, it's so hard choosing a telescope. I wanna make sure I make the right decision.
So what exactly does the second number in the 80x600 mean? I thought it had something to do with the length of the scope?
Frosty
Frosty,
I think you just have to accept that within minutes of buying whatever you end up with, you'll have found something better And if not that quick, then within a couple of weeks or months, you'll have found out some of the tricks of the trade and will want to upgrade or buy extra 'stuff'.
It's just the way it seems to be in this game - sorry !
And if not that quick, then within a couple of weeks or months, you'll have found out some of the tricks of the trade and will want to upgrade or buy extra 'stuff'. 
