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Hi and a request for advice!

GregD

By GregD
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GregD

GregD

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Hi,

I have recently signed up to the forum and would like some advice too! Cheeky or what!

I currently have a Celestron Nexstar 130 SLT that I am looking to upgrade. When I bought the scope I was hoping to do some imaging with my DSLR but I have found out that the camera will not get close enough to focus without using a Barlow and also an Equatorial mount is best. Ho hum, excuse for a new scope!

My limit is around £800. As well as the above I want a GoTo mount, ability to link up to a laptop with Stelarium and an 8 inch mirror. I can get the Celestron C8 NGT new for that money which seems to tick all the boxes.

However, I could possibly get secondhand a Celestron C8 SGT or even a Meade LXD75 for that money. Any opinions? Does the Meade connect to the laptop the same way as the Celestron?

Thanks in advance.

Greg

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JamesM

JamesM

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Hi Greg and welcome to the forum. If you want an 8" reflector on a goto mount that facilitates auto guider correction to its motors to help it improve tracking, then the answer would be this. Unfortunately, it is a little over your budget but if you wanting to image deep sky objects (DSO's) such as galaxies and nebula, then the HEQ5 is the minimum mount that you will need. You can connect it to Stellarium via free EQMOD software, it has proven reliability in its tracking and also has a sufficient payload capacity to carry all the kit (which in theory should never exceed half of this capacity). To image these objects you will need to use an equatorial mount. An alt-azimuth forked mount that is found with the Meade telescopes would need the addition of a wedge, which effective tilts the horizontal axis of the mount backwards in order that the scope now moves across the sky in an arc which mimics the path of the objects as they move across the sky.

To be honest, if you are embarking on imaging, then you might want to get hold of a copy of Steve Richards' "Making Every Photon Counts" (FLO £19.95) to provide you with a comprehensive and instructional overview of what kit you need and why you need it to take good consistent images. It will also help you determine a realistic budget from the start and so this book might even save you money. We don't want your first image of a black hole to be the one in your wallet! Hope that helps.

Clear skies

James

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sgazer

sgazer

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hi Greg and welcome,

to answer your questions (or just to confuse you!), for imaging I would recommend a HEQ5 over the Celestron CG5-GT mount. I've had both and the HEQ is in a different league, CG5-GT is very noisy too, especially when your out late at night! Problem is price, but they can be found second hand at a reasonable price (paid 500 for mine).

As for a scope; focal ratio is the important thing (not aperture as with visual astronomy). Most Newts are f5, which is good. More aperture (bigger scope) at f5 will just give you a longer focal length (hence slightly more zoomed in) and the following problems; bigger size, more weight, bigger/better mount needed, higher cost, harder tracking, yet the image will be just as bright as a smaller f5 scope. With high megapixel DSLR cameras these days, it's easier to just crop the image a bit than to get a bigger scope. Hence I would recommend a 150pds newt. Compact, lightweight, f5, easy to mount, easy on the mount (you might want to add a guide scope too), cheaper, easy tracking, big enough for visual too.

What DSLR and lenses do you have? Before you buy more kit, I would just mount the DSLR on the SLT with a 50, 100 or 200mm lens on (make up a bracket from a length of dovetail bar and an L shaped bracket with the appropriate holes and screw to mount the DSLR. Do some 30s exposures, lights, darks, flats, stack and process to see if you like imaging. Most of that will be free/cheap to try. I went through everything in my signature list, before coming back to just using the SLT with a camera and lens. I can get an image of the horsehead within 10mins of thinking about setting up!

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glowjet

glowjet

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Hi Greg and welcome to SGL, Sgazer and JBM seemed to have put things into perspective for you, If you just invest in the mount for the time being, and if you can detach the 130 scope from its Alt/Az mounting, with rings and a dovetail you could attach this to the HEQ5 and progress from there for a short period, to give you some imaging practice, just a thought :)

John.

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Quatermass

Quatermass

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Welcome to the forum Greg soon be joining the darkside then jolly good take a look at my blog and others to see what can be done with the skywatcher 200p and 150p. Mount wise go for an HEQ5 if you can afford it as the mount is all important for astrophotography.

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GregD

GregD

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Many thanks indeed for all the Welcomes and Advice.

I should have made more clear that I am primarily interested in visual astronomy with imaging a second string. Having previously looked through other 8 inch scopes, the difference between them and my 5 inch scope were very apparent.

Also, I have somewhat put the cart before the horse, in that I have just sold my Nexstar 130 SLT before I have obtained a replacement!

To be honest, £800 would be my top limit and I would be happier with new rather than second hand for obvious warranty reasons. The search continues but I have taken on board any suggestions.

Seems like quite a friendly bunch on here!

Greg

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GregD

GregD

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Yes I did, It was really frustrating as you wound the focuser in, you could see everything coming into focus and then it would just run out of travel. Common prob with that type of scope I was told at the time.

Greg

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GregD

GregD

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Hi all,

Well, I eventually took the advice given here and bought myself the Skywatcher 200P with the HEQ5 mount. Good time to buy it in June when it only gets dark for a couple of hours!!

I took it on holiday to France with me a couple of weeks ago (only took up half the car!) and eventually got it set up and working. Took me a whole evening before I found you could only see through the polar alignment scope if you had the tube in a certain position! :embarrassed:

Just a couple of queries, when polar aligned properly, should it slew straight to the suggested star in the Synscan process, or does it just send you to the general area of the sky where that star is located? The latter happened to me and I manually centred it, the second star suggested was then spot on and it then found all the objects I asked to with no probs.

Secondly, what is the purpose of the illuminated bit in the polar alignment scope? I could not make out anything when it was lit up, so aligned it with it turned off and then flicked it on and off to check it was correct. Is this the right way to do it?

Thanks.

Greg

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