Which telescope?!?!?!?!

[RoloFanatic]

Hi,

I am looking for a telescope with GOTO capabilities, that is portable and a telescope that will bea good starting point for astrophotography.

My three options are:

1. Celestron NexStar 8SE

2. Meade LX90SCT 8" telescope

3. Celestron C8-SGT (XLT) computerized telescope

(I can only afford any of these because they are second hand, my budget is £1000)

Any suggestions or advice on which one is best or another option will really help,

Thanks

(P.S. some of you may have read other posts by me about choosing a telescope, sorry for posting so many about the same topic, but i really want to get the right one)

[LukeSkywatcher]

Nice choice of scopes to pick from.

I really cant decide which one to pick.

Sorry i am not helping.

I have the 8se and love it.

The C8 is a cracker by what i have read.

For imaging, you will really need something on an EQ mount. But a Go-To system that can track objects will work fine also.

I'm not much of an imager, so i cant be of more help.

Sorry.

I think the C8 will be a popular choice with people who reply.

[ollypenrice]

By astrophotography, do you mean deep sky or planetary? If planetary, then the SCTs on your list will do the job well, even on an Alt Az mount.

If you mean deep sky astrophotography I think you are looking in entirely the wrong direction. A large aperture long focal length telescope is absolutely not the right way to begin AP, especially if you are budget conscious. The key to AP is getting the setup to track well enough. Short focal lengths (say in the 500mm region) are tolerant. By a metre it is getting harder. By two metres you are in 'serious mount' territory and for me that means four times your total budget, though with a lot of effort and a lot of failures you could get cheaper mounts to do it - maybe. A bit of wind at long FL and you are out for the count.

To begin AP get a short focal length fast apo refractor on a GEM (say HEQ5) and rejoice that you didn't make it any harder for yourself by trying to start at a long focal length.

To see what all this is about have a look at Steve Richards' book Making Every Photon COunt available fropm FLO above.

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=1793644788&k=r8HTK72

[JamesM]

Have to agree with Olly in getting Steve's book. Will tell all you need to know, what kit to to get and why you need it to be able to take good consistent images that will meet your expectations. It might be worth looking through the imaging forum on here to check out the kit that people are using - no need to reinvent the wheel and there really isn't any shortcuts if you want to experience more fun than frustration. Often when people are exploring the idea of imaging, it is natural for the conversation to gravitate towards the equipment or the data collection side of the activity. Of course this is only half of the 'fun', the other half being the processing of this collected data to produce an aesthetically pleasing image. Fortunately, there is a lot of free software out there to get you started but there are other bits of software that will have to be paid for. The above book is ideal in helping you to formulate the right budget from the start at the level of imaging you want to explore.

James

[umadog]

If you really want to get the best scope to begin AP then you want to read the book Olly recommends. Astrophotography is not straightforward. You need to sit down and do some reading in order to make the best choice. Generally speak, though, a short focal length refractor is probably the best starting point (especially in your budget range).

[DirkSteele]

It has been touched upon but not specifically explained why the mounting solution that the first 2 scopes you listed use would not be suitable for long exposure deep sky astrophotography. They both come in an Alt Az configuration and despite tracking objects because one axis is not polar aligned, over time the field will rotate thus making it impossible to build up long exposures needed for deep sky. This can be fixed with a wedge that allows polar alignment. I have used my Alt Az mounted SCT for some limited planetary and video astronomy (max exposure is 10 secs) and it has performed well in that function. Field rotation is not an issue over such short periods.

As for scope choice, everyone above is spot on. The longer the focal length the harder it gets.

[RoloFanatic]

So these scopes are not ideal for DSO imaging but how would they do for imaging other objects e.g.planets?

[DirkSteele]

For planetary imaging the scopes will perform well, even using in Alt Az configuation. The longer focal length will provide a larger image scale which is of benefit when imaging planets, and field rotation will not an issue over the time scales of planetary imaging (say 30 second to 2 minute video which you then select the best frames from and stack for the final image using a software program like registax).

[sgazer]

There's 2 things to consider for imgaging DSOs. The scope and the mount. (Camera too, but that's not part of the OP). Choices 1 & 2 come on a ALT/AZ mount so you'll really need a wedge to EQ mount them for long exposure, which are neither cheap nor easy to use. So option 3 with the EQ mount would be better. I've used a CG5-GT and they are good, but a bit noisy and not quite as good as the HEQ5.

Then there's the scope. All those you have chosen are SCTs with a 2m focal length at f10. This is a very long focal length and slow focal ratio making imaging very difficult, so you will definately need a f6.3 focal reducer. f6.3 is still a little slow and the resulting 1.26m focal length still a little long, particularly as the weight of the C8 will be pushing the imaging performance of the CG5-GT. For a given camera sensor size, eg. DSLR, the focal length will determine what field of view you capture, like a zoom lens focal length. The focal ratio will determine the brightness and hence exposure times, which you want to be as fast as possible. I would suggest something at f5 with 600-750mm focal length, which will make exposures shorter and place less demand on the mount and tracking. As DSLRs have high MP sensors these days (like 12MP vs 6MP of a 300d), you can more readily crop the image, thus effectively 'zooming in' without having to have a long focal length scope.

For planetary imgaging, a long focal length is good and an ALT/AZ mount is fine as you'll just be taking many fast exposures with a webcam.

[RoloFanatic]

There's 2 things to consider for imgaging DSOs. The scope and the mount. (Camera too, but that's not part of the OP). Choices 1 & 2 come on a ALT/AZ mount so you'll really need a wedge to EQ mount them for long exposure, which are neither cheap nor easy to use. So option 3 with the EQ mount would be better. I've used a CG5-GT and they are good, but a bit noisy and not quite as good as the HEQ5.

Then there's the scope. All those you have chosen are SCTs with a 2m focal length at f10. This is a very long focal length and slow focal ratio making imaging very difficult, so you will definately need a f6.3 focal reducer. f6.3 is still a little slow and the resulting 1.26m focal length still a little long, particularly as the weight of the C8 will be pushing the imaging performance of the CG5-GT. For a given camera sensor size, eg. DSLR, the focal length will determine what field of view you capture, like a zoom lens focal length. The focal ratio will determine the brightness and hence exposure times, which you want to be as fast as possible. I would suggest something at f5 with 600-750mm focal length, which will make exposures shorter and place less demand on the mount and tracking. As DSLRs have high MP sensors these days (like 12MP vs 6MP of a 300d), you can more readily crop the image, thus effectively 'zooming in' without having to have a long focal length scope.

For planetary imgaging, a long focal length is good and an ALT/AZ mount is fine as you'll just be taking many fast exposures with a webcam.

So i would be better off buying the HEQ5 and SCT separately?

I think considering all you've said i will probably go for the Celestron C8-SGT (XLT) and buy the HEQ5 for it because although i do want to try my hand at AP i also wasnt to see some good detail for high magnification viewing.

Thanks for all your help, hope we get some clear skies soon :smiley:

[Northern Soul man]

Hi Ya Rolo (Luv em meself) - I've owned a few scopes in me time - a dob (12" revelation) and an sct (Meade LX90) - purely for visual work, and found both scopes really capable, the dob was fantastic - so was the Meade - but two very different scopes, I know the dob was larger but the SCT was my favourite - for such a small tube the Meade performed really well and as a whole package I got on better with the Meade - think I owned it for about 5 years, never had a problem with it - the dob was a bit of a pain when observing overhead due to the mount, but the SCT with Goto was amazing and could rattle off object after object and viewing the zenith was very comfortable - so upgraded to the Celestron - you have to realise that moving to a larger aperture does'nt suddenly mean that objects are bigger - just that mag for mag the objects are brighter in a larger aperture - done a little webcam work with the SCT, not really for me though - just being out under the stars does it for me - so the SCT was a good choice for me - but not to everyones taste.

I'm a little bias when it comes to the humble SCT, alot of gazers prefer the Dob/Newt, but for me, the scopes you mention are really nice pieces of kit, purely from a visual point of view you cant beat a fork mounted SCT - easy set up and very stable, but for a little AP the mount is king and expensive and dare I say a little fiddley to set up - polar alignment - tube orientation in different parts of the sky - so the ideal would be an SCT tube on an EQ mount - but remember, if your setting up taking down and setting up every night you have to allow extra time.

I really miss my LX90 - if I could afford to have kept the LX90 and purchase the CPC1100 I would have done, but after alot of debate I sold the Meade and the 12" dob to part fund the 1100, with this cloud, not had alot of time to use it - but the stars will still be there night after night above the cloud cover - so as like all on here I'm in it for the long haul. Regards Paul

[RoloFanatic]

Hi Ya Rolo (Luv em meself) - I've owned a few scopes in me time - a dob (12" revelation) and an sct (Meade LX90) - purely for visual work, and found both scopes really capable, the dob was fantastic - so was the Meade - but two very different scopes, I know the dob was larger but the SCT was my favourite - for such a small tube the Meade performed really well and as a whole package I got on better with the Meade - think I owned it for about 5 years, never had a problem with it - the dob was a bit of a pain when observing overhead due to the mount, but the SCT with Goto was amazing and could rattle off object after object and viewing the zenith was very comfortable - so upgraded to the Celestron - you have to realise that moving to a larger aperture does'nt suddenly mean that objects are bigger - just that mag for mag the objects are brighter in a larger aperture - done a little webcam work with the SCT, not really for me though - just being out under the stars does it for me - so the SCT was a good choice for me - but not to everyones taste.

I'm a little bias when it comes to the humble SCT, alot of gazers prefer the Dob/Newt, but for me, the scopes you mention are really nice pieces of kit, purely from a visual point of view you cant beat a fork mounted SCT - easy set up and very stable, but for a little AP the mount is king and expensive and dare I say a little fiddley to set up - polar alignment - tube orientation in different parts of the sky - so the ideal would be an SCT tube on an EQ mount - but remember, if your setting up taking down and setting up every night you have to allow extra time.

I really miss my LX90 - if I could afford to have kept the LX90 and purchase the CPC1100 I would have done, but after alot of debate I sold the Meade and the 12" dob to part fund the 1100, with this cloud, not had alot of time to use it - but the stars will still be there night after night above the cloud cover - so as like all on here I'm in it for the long haul. Regards Paul

Thanks Paul for your advice and experience,

I was actually considering buying a 10" dob myself but the size of the SCT's won me over

Thanks again

[LukeSkywatcher]

Thanks Paul for your advice and experience,

I was actually considering buying a 10" dob myself but the size of the SCT's won me over

Thanks again

My 8SE is sitting in the lounge right now not getting used due to weather, but today i could not help but look at it and admire it. Its such a powerful scope yet it is so compact and lightweight for an 8" scope.

I am a wheelchair user and i can easily handle the 8SE, so any able-bodied person should have NO trouble.