Help with scope choice...

[brantuk]

To do any reasonable astro photography you will need to "guide" the mount. This means a second telescope mounted firmly to the imaging scope that follows a nearby star and sends tracking corrections back to the mount. It also means a second camera or a stand alone "guiding eyepiece".

A popular scope for guiding is the Skywatcher ST80. A webcam like the Phillips SPC900 can be used as a guide camera when hooked up to PHD guiding software (PHD is free). This is perhaps the cheapest guiding setup that I have looked into but you'd need to google current prices.

For the imaging scope I'd recommend a short tube wide angle refractor. The important measure here is focal ratio. For Deep sky objects you need a fast f-ratio of 6 or less. F7 and above is generally regarded as a slow scope.

Most useful comments about the mount/tripod have allready been made above. I would suggest a phone chat with FLO in the first instance who will give you some great advice on what equipment to be looking towards for your budget.

Also try Ian King Imaging who are expert suppliers in this field.

Hope that helps

Incidentally this question may be better placed amongst the imaging experts in the imaging threads. Let me know and I'll move it if you wish.

[Dave Moulton]

Hi,

Reading through the posts you have been given some sound advice already I’ve been imaging seriously since 2007 and have had a variety of scopes and cameras so have trodden the path so to speak

The advice regarding a small refractor is sound as they fit the bill with regard to wide field imaging with A DSLR and ED doublet of around 80 mm will not be a mistake as the main imaging scope its true you don’t need large telescopes to take good deep astro pics. Forgive the image but just for your interest this was my first guided pic taken with a standard Canon 350D I tookthis using an 80mm refractor .It’s a guided exposure so a second scope and guide camera was used to keep my EQ6 Pro mount tracking correctly.

The mount is as others have said is very important and an EQ5 or EQ6 would be a good starting point. You could add a small refractor on that and take short exposures of maybe up to 2mins with your DSLR add a guiding rig later as funds allow

This can be a deep pockets hobby the good news is a lot of free software can be had to help

Dave Moulton

[rocketandroll]

Thanks all for the ongoing advice...

Dave, that image is incredible, way beyond my expectations :-) As I said, my aim for now is simply imaging something that is recognisably not just a blurred star :-)

As I have zero experience I think I'd prefer to start off as simple as I can, then expand my set-up as I gain confidence. If I can get anything at all with shorter exposures and not using a seperate guide scope, then I'd probably rather find my feet on a simpler set-up and add that in as my confidence and understanding grows so that I can then achieve better things in the future.

And yes, looks like getting the GOTO function on the mount from the outset would be wise, it'd certainly be a pain to have to add it later at a higher cost.

Thanks all... and keep the info coming... I'm hoping that book arrives soon and I can get reading :-)

Ben

[Dave Moulton]

Ben,

Sounds like a good plan. An EQ Mount with goto is highly desirable so long as it has a ST4 port then it will be capable of guided Astrophotography later on . This type of mount will allow you to build and vary your kit over time.

A lot of easily imaged deep sky objects are invisible in the eyepiece so a goto comes into its own as it puts the object on the chip regardless.

That pic was not put up to scare, you sorry if it did, the reality is that is not a great pic by todays standards as I said it was my first guided picture and took about 9 weeks to master the techniques to get that far, all the tips to achieve it came from people registered on here.

Mistakes on buying kit will be expensive so I think you are heading down the right path, asking the right questions and you should be OK.

Most of my kit came in second user due to budget, including my EQ6 Pro Mount otherwise I would have to have made some tough choices and bought inferior kit.

Scope wise an ED80 Refractor with FPL53 glass in a doublet configuration such as the Skywatcher Pro would deliver around 90% of the performance you could expect from the top end refractors, this at 30% of the price.

Dave

[rocketandroll]

Just a quick one to say thanks all for your ongoing help...

Unfortunately we got some bad financial news today so the scope buying is gonna be on hold for a while... maybe a year... but still gonna hang around and learn as much as possible and try and get to a point where I know exactly what I want to do and how to do it when I can invest in the equipment.

Ben

[rocketandroll]

hmmmm.... well, the financial situation is less bleak than anticipated so a scope is still on the cards... however, having now read over half of that wonderful book... I am actually finding myself put off the idea of DSO imaging :-(

I was (perhaps stupidly) thinking this was something I could ease myself into.... get the basics down first, generate a passable image or two, then build up on my equipment and the complexity a I go on...

That doesn't seem to be the case :-(

Seems 90%+ of the complexity and the cost is inherrent to the subject matter, no matter how low your expectations.

So... some advice first to see that I haven't missunderstood any of it.

Using my DSLR as the imager... it seems to say that the ONLY way I can focus the camera is to link it to a PC and use some special software... whilst in the field?

The thought of taking a laptop to the middle of a cold wet field doesn't appeal, not unless I needed it anyway for a CCD imager.

Also... it seems to suggest that it isn't worth trying to image without a guide scope... again, a complexity (having never even used a scope before) I was hoping to put off till later.

If both of these points are right... then I think I'll probably leave the DSO side of things alone for now.... if I could achieve something with a decent (HEQ5 PRO) mount and a 80mm ED refractor and the EOS 20D... without having to add a guide scope and a laptop straight away, I'd give it a go.

So... assuimng I'm having to abandon hope of getting into DSO imaging.... I may still look at getting a scope for observing.

This may seem like a stupid question but are there any vaguely affordable (sub £500 for the OTA) scopes through which any DS objects at all are visible as more than a feint blur? Or is the very nature of DS objects such that they are not really visible through anything but the most massive of scopes with enormous light gathering power?

I won't add another 'which cheap scope should I buy' thread... I just wonder what I should be expecting out of what I can afford?

Cheers again all for he advice!

Ben

[nightfisher]

Hi again ben, im gonna give a bit of advice here, have a very good look at the TAL100rs ota, married to an EQ5 mount, the whole plot will cost about £500, maybe a little less, this is a fantastic scope to observe with and it will show some dso`s i.e M42 very clear with good detail M31 will be half decent, not one person on here has a bad word to say about the tal, and if you mount the dslr at prime focus you will get fantastic lunar and planet shots

Just re read you last post, with a telescope no matter what size scope you wont see much in the way of colour with dso nebula, its only camera`s that draw out the colour

[rocketandroll]

Thanks Nightfisher

Looks like a nice scope...

Is a refractor the best type of scope for observing DSO's?

The idea of being able to observe, and image the planets and moon certainly has appeal too... I guess it's a matter of priorities and making a decision on what I want to do most! :-)

The biggest killer on the DSO imaging for me seems to be the problem of focus.... I just need to find out whether I can only focus the EOS 20D using a laptop or if there are other options...

Anyway, thanks again all for the ongoing advice!

Ben

[nightfisher]

if your imaging lunar and planets i would think you can bring the eos to focus using the display panel i guess it has one? i dont use dslr`s but some others will be able to give more info on this issue

[whooshbang]

Thanks Nightfisher

Looks like a nice scope...

Is a refractor the best type of scope for observing DSO's?

The idea of being able to observe, and image the planets and moon certainly has appeal too... I guess it's a matter of priorities and making a decision on what I want to do most! :-)

The biggest killer on the DSO imaging for me seems to be the problem of focus.... I just need to find out whether I can only focus the EOS 20D using a laptop or if there are other options...

Anyway, thanks again all for the ongoing advice!

Ben

Hi Ben, I'm definitely no expert in Astrophotography so personally I'm gonna start out with the piggybacking method to get used to things like focusing and tracking the objects i wish to photograph. I have read that one way to focus a piggybacked camera is to point it at a star or cluster, such as Pleiades, then focusing best you can in the camera viewfinder take a shortish exposure and review the shot on your camera LCD screen. By zooming in to the shot you'll be able to check your focus and fine tune it by taking further short exposure and adjusting the camera lens focus ring until best focus is achieved. The 20da features a 30 sec live view on the camera LCD screen which gives you enough time to get focused, not sure if your 20d has this function though?

Also not sure(so i should probably shut up now) if the above method works at prime focus but i don't see why not. Also a Bahtinov Mask can be used for focusing and no doubt other methods that do not require the use of a laptop in the field.