Telescope vs telephoto lens

[DigitalHeMan]

Hi all,

I've been involved in 'terrestrial' photography for a while and would now like to expand into astro photography. I've been doing a lot of research, here on SGL, and using my friend Mr Google, and I understand the basics around using an equatorial mount to track the stars etc. However, there's one thing that keeps going round and round in my head.....

A bit of background with my photo equipment - I'm lucky to have quite some telephoto lenses, ranging from a 200/2, to a 300/2.8, and a 600/4, plus various teleconverters, having done a fair amount of wildlife photography in the past.

So, initially I was looking at the Celestron Advanced VX with 6" SCT. However, research has suggested that for DSO AP this might be a bit long, so I've come up with a couple of options:

1) go with the above, possibly combined with a reducer to reduce the length

2) go with the AVX mount, but choose a shorter scope, like the Skywatcher Evostar 80ED

3) Evostar 80ED but with a NEQ5 or 6

But, looking at the 80ED and its 600mm focal length, I could also just use my Nikon 600mm or 300mm with teleconverters In which case:

4) AVX a or NEQ mount with 600mm

5) Skywatcher Star Adventurer mount with 300mm plus teleconverter.

So, I guess my question is, considering I already have some telephoto lenses, what is my best option? Is a good telephoto lens a suitable replacement for a decent telescope? If not, why not?

Thanks for any help and advice.....

Simon

[wxsatuser]

May be start with the lenses and move on if you really get the bug.

I have used the 80ED and my 200mm L ,  I do like the wider field shots.

[Alien 13]

I think that you only have to look at some of the images posted on SGL to know that the premium lenses can match all but the very best scopes but i would go for something better than the Star Adventurer if you decided on this route.

The mounts you already listed would be fine as would an astrotrac it depends how portable it needs to be.

Alan

[nmoushon]

If you're serious about AP I would not suggest the SCT on the AVX. The FL, even with reducer, is still going to be long and without guiding would be very difficult to get exposure up to even a minute in length. Even with guiding I'm not sure if that mount can handle that kind of focal length.

If you really want the SCT then I would suggest at least the HEQ5. Its a solid mount that would support that kind of FL and thus would easily handle any ED80.

Now for lenses: The typical reason people don't tend to use lenses is because to get a lens that works comparably to a scope of similar FL and speed costs a LOT more. Most of the cheaper lenses that compare to scopes, price wise, tend to have bad CA on stars when you start doing long exposures. They just arent designed with long exposures and point source lighting in mind. They work great for daytime photography but not the best for us and our hobby. There are people that do do AP with lenses and produce excellent images but the lenses tend to be very high end and they usually have them already before they get into this hobby(for the most part). So for people like you that have a list of lenses to choose from already then all you need to do is go out and give it a try. I'm not knowledgeable enough about lenses to tell you if your lenses will work well for AP or not, sorry. But you can go to astrobin.com and search for your lenses and it will produce photos that were taken with that lens. You could also go and buy just the mount to start with and then test your lenses. You'll need a mount anyways. So if you can't find examples you can buy your kit in 2 purchases and test what you got first. And if they don't work well you can go buy a scope.

[Owmuchonomy]

Well, in my view you can do all of it. One way of approaching it is to focus in what you want image, work out the image scale and then select the appropriate equipment. You can do that here:

http://www.12dstring.me.uk/fovcalc.php

[Knight of Clear Skies]

I suggest browsing the widefield imaging forum to get some idea of what is possible. Most images in there are taken with wide angle lenses but there are some taken with short to medium telephoto lenses as well.

[hobsey]

Somewhere on here there is quite a long and heated thread with regards to which is best, telephoto or telescope.

Very interesting read and reading everyones opinions, can't find it at the moment as I'm on tapatalk.

[oldannie]

If considering a telescope and attaching a DSLR it is also worth thinking about the DSLR you will be attaching - a full frame camera will have quite an impact on which scope you can use though I only know this because of some of the advice I've had on this site in response to some of my posts.

Annie

[SJP]

http://stargazerslounge.com/index.php?/topic/222735-Telephoto-Vs-Telescope is the link to the thread Hobsey mentions.

[hobsey]

http://stargazerslounge.com/index.php?/topic/222735-Telephoto-Vs-Telescope is the link to the thread Hobsey mentions.

Thank you.

[DigitalHeMan]

Thank you for all the advice. I will check out the link provided above and do some more research.

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