Telescope to move into imaging eventually

[russp]

Been into photography a while and have always loved the nigh sky and in particular the pictures of DSO's. I've decided it's time to invest in some proper equipment with a view to moving into imaging once I've worked out how it all works.

Have set myself a budget of around £2500-£3000 for the complete hardware setup (not including the DSLR or laptop). I'm thinking I want a HEQ5 Pro synscan mount (I don't want anything heavier) £760  and an apochromatic ideally triplet fastish scope with a focal length around the 700mm mark. (I already have a fastish 400mm SLR lens so I can mount that for bigger fields of view?) I'm thinking I'll guide it  using an Orion Awesome Autoguider (£340) so I'm looking at around the £1000 mark for a scope (but could maybe push that a few hundred pounds if the returns were worthwhile)  - I've pretty much decided I only want to look at refractors and keep say £500 for connectors filters eyepieces etc?

So the question is, is this a realistic set uo to get some decent pictures and what scope should I go for?

Ones I've seen so far include;

Explore Scientific ED APO 102mm f/6.7 Essential  - £830 but comes with no accessories (Do I even need a finder scope on a goto mount?)

Ascension 102ED Triplet APO - £1200

William Optics GT-102 Triplet Refractor - £1300

Struggling to find much else that fits the bill - ideas? - comments? 

Thanks

Russ

[swag72]

Here's a couple of thoughts Russ.

Firstly you mention that you are going to use a DSLR? The only filter you will need really is a LP filter, so you can save a little from that £500!

Firstly get the book 'Making Every Photon Count' if you haven't already done so, it is a bible for DSO imagers.

The HEQ5 is a good mount and will serve you well with a smallish refractor.

I can not comment on your scope choice as I have no experience of them, but someone will be along soon with some ideas I am sure. Are you adverse to buying second hand? ABS often have good stuff and that way you can afford more!!

I wouldn't bother with the Orion Awesome guider package - A standard 9x50 guider, an adapter from Bern at Modern astronomy and something like a QHY5 will do you fine - Assuming that you are looking at guiding using a laptop. Add into that an EQDIR cable and you can be up and running with EQMOD in no time, which is a really good piece of control and guiding software.

You may like to put some money saved towards some software. Pixinsight is good for imaging and is used by many, as is Photoshop.

There's loads to think about! If you already have a 400mm camera lens then perhaps you'd be better with a longer scope as a bit of addition to your arsenal.

Just a couple of ramblings really to add to other people's thoughts along the way.

[Leveye]

Don't forget that some of these refractor scopes will require a field flattener and that can cost another 350 dollars.

[andrewluck]

No need to commit to the scope just yet. Wide angle has a lot to recommend it when starting out so just mount the camera and lens on your new mount and start learning from there. Once you've mastered how it works then you'll have a better idea of what focal lengths are the most use for you. Personally, I'm not keen on the mid sized refractors. There's not enough focal length for galaxies and not enough fov for nebulae (unless you're into building multi-pane mosaics).

Andrew

[russp]

Thanks for the comments so far, swag72 you've voiced one of my thoughts about maybe getting something longer straight off give that I have a decent zoom camera lens. I like the idea of just getting the mount and playing with the camera (definately one less new thing to learn) but I wouildn't be able to guide it which from my reading would restrict it's use more than a litttle? Or could I mount a guider with the camera? If I could do that then that would probably be a good way forward although if I get a scope it will inevitably be used as much for visual as it will for imaging.

Wondering about maybe stretching to a 115 such as the 

      Altair Wave Series 115 F7 ED Triplet APO (805mm) 8Kg (includes accessories)

or maybe 

    Explore Scientific ED APO 127mm f/7.5 Essential (952mm)  7 Kg

or

   Meade Series 6000 115mm f/7 ED Triplet APO OTA (805mm) 8Kg

Which all seem to be a similar price - but would the HEQ5 be up to imaging with these slightly larger scopes?

I'd realised that I'd need a field flattener, connectors, probably an additional eyepiece (or two) and filters which is why I'd set aside the £500. 

[swag72]

For guiding you can do it side by side for example on a dual bar. Camera on one end and guider on the other - Job done!

Here's my thoughts on the size scopes you've mentioned. Yes the HEQ5 will cope, but ........ I found it definitely preferred shorter and I got better guiding using a shorter scope. Also ............ Do you think there's THAT much of a difference between 400mm and 800-900mm? I don't personally think there is, and found that 900mm was a very in-between and un-useful focal length. Too long for many nebs and too short by far for many galaxies. Have you looked on a FoV calculator? http://www.12dstring.me.uk/fovcalc.php

[ollypenrice]

I'd start again with the thought process. People coming into this often take the DSLR as a given, and I wouldn't do that. They are not astro cameras. They have too many pixels, too much noise and not enough bit depth. If you want to take great astrophotos get it right from the outset and think CCD, monochrome and filters. The CCD camera - and only the CCD camera - explains why amateurs with three inch scopes can beat professional images of twenty five years ago taken with ten tonne telescopes and huge photographic plates. Amateur mounts and optics have advanced a little. The CCD camera is the revolutionary. I'm simply re-iterating advice given to me by Ian King around seven years ago and in those seven years I have never for one second doubted the quality of the advice.

Give me an astrophoto budget like yours and I would start with a CCD camera (probably an Atik because they work) and build from there. An HEQ5 will cope admirably with a small refractor and then you just need... a small refractor. There's plenty of choice.

Sure, I'm wedded to CCD imaging. But the best advice I can give you is, forget the DSLR stage if you mean business. Nobody could be less IT orientated than I am (OK, my wife is worse!) but if I can get round the IT side then anybody can.

Olly  http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2277139556&k=FGgG233

[frugal]

Olly, 

Why do you say that DSLRs have too many pixels? I would have thought the more pixels the better.

[lensman57]

Been into photography a while and have always loved the nigh sky and in particular the pictures of DSO's. I've decided it's time to invest in some proper equipment with a view to moving into imaging once I've worked out how it all works.

Have set myself a budget of around £2500-£3000 for the complete hardware setup (not including the DSLR or laptop). I'm thinking I want a HEQ5 Pro synscan mount (I don't want anything heavier) £760  and an apochromatic ideally triplet fastish scope with a focal length around the 700mm mark. (I already have a fastish 400mm SLR lens so I can mount that for bigger fields of view?) I'm thinking I'll guide it  using an Orion Awesome Autoguider (£340) so I'm looking at around the £1000 mark for a scope (but could maybe push that a few hundred pounds if the returns were worthwhile)  - I've pretty much decided I only want to look at refractors and keep say £500 for connectors filters eyepieces etc?

So the question is, is this a realistic set uo to get some decent pictures and what scope should I go for?

Ones I've seen so far include;

Explore Scientific ED APO 102mm f/6.7 Essential  - £830 but comes with no accessories (Do I even need a finder scope on a goto mount?)

Ascension 102ED Triplet APO - £1200

William Optics GT-102 Triplet Refractor - £1300

Struggling to find much else that fits the bill - ideas? - comments? 

Thanks

Russd

Hi,

For imaging DSOs and given the choice of brands that you have listed, I would suggest that you consider, Ascension 80mm Apo triplet which is a fast F6 in native form and works very well with a Televue TRF 2008 0.8 Ff/FR or the new WO 81GT which is also a fast F5.9 and has its own Flatner 6. I have the Ascension which incidentally is the same as the Meade 5000 series and it is a good scope considering its modest price and mine also came a proper 2" diagonal and a couple of EPs but no tube rings. Heq5 Pro is the minimum standard of mount that you'd need and the suggestion of a 50 mm finder guider makes sense, for such short and fast scopes anything longer is unnecessary,I have guided well up 1200s with the 50mm finder and an ASI 120 MM. If you are going to use a DSLR you'd definitely have to use either an FF or an FF/FR to correct the field. The use of a good LP filter such as IDAS P2 ( now replaced with D1) is almost mandatory if you live anywhere near a light pollution zone. The cost of the above scope, mount, filter and guiding camera and finder and lP filter is roughly £2000.00 and covers most of the DSOs that we hobby people are likely to image. The Ascension and the WO GT81 are roughly the same price.

Regards,

A.G

[ollypenrice]

Olly, 

Why do you say that DSLRs have too many pixels? I would have thought the more pixels the better.

No. Your pixels should be matched to your focal length. If they are too small they don't get enough light and this means you end up with a poor signal to noise ratio. If they are too big you lose resolution and even end up with a blocky, pixelated look. The key statistic is the resolution you have in arcseconds of sky per pixel. You can work that out using this calculator. http://www.12dstring.me.uk/fov.htm

Opinion is changing on what represents a good figure. It was widely believed that there was no point in going much below about 2 arcseconds per pixel because the seeing smears out the theoretical resolution below that scale. This has been shown by many expert imagers to be wrong. Some go as low as 0.4 arcseconds per pixel. However, if you do this you will have a highly resolved but very, very slow system. If your camera is not cooled your exposure times will have to be curtailed because of heat build up and you will never obtain enough signal. The DSLR formula of no cooling and small pixels is, therefore, not optimal at longer focal lengths. Note that if you have a monochrome CCD camera with small pixels you can use it 'as is' at short focal lengths or you can bin it 2x2 (combine 4 pixels into 1) if switching to a long focal length. Binning destroys the colour information in One Shot Colour systems but not in monochrome-with-filters.

I've imaged from 0.6  to 3.5 arcseconds per pixel. I felt that the former was on the slow side and the latter acceptable, though it doesn't reach the resolution of which the optics are capable. However, it is fast and allows you to go deep.

There is no doubt that the best DSLR images are taken in incredibly fast optical systems like the very expensive Takahashi Epsilon.

Olly

[frugal]

Olly, I don't doubt your statement for a minute; looking at some of your images you obviously know your stuff, however I am confused. Looking at the Blackwater Skies toolbox, using a sample scope of an Evostar 80 ED, my Canon 60d has a pixel size of 4.3x4.3, or 1.48x1.48 arc seconds per pixel. Looking at other "common" astro CCDs they do not seem to be that dis-similar:

Atik 383L+: 5.4x5.4 (1.86"x1.86")

Canon 60D: 4.3x4.3 (1.48"x1.48")

Starlight Express H694: 4.5x4.5 (1.56"x1.56")

Atik 490: 3.7x3.7 (1.27"x1.27")

QHY8 pro: 7.8x7.8 (2.68"x2.68")

So the DSLR seems to my untrained eye to have a pixel size on the same order of size as popular DSO imaging cameras, all of which are well within your 0.6 to 3.5 range you have worked with. I understand that CCDs are much better for other reasons such are Quantum Efficiency, cooling and no nasty IR filtering, but from a purely pixel size argument I remain confused. What am I missing?

[laser_jock99]

I'd start again with the thought process. People coming into this often take the DSLR as a given, and I wouldn't do that. They are not astro cameras. They have too many pixels, too much noise and not enough bit depth. If you want to take great astrophotos get it right from the outset and think CCD, monochrome and filters. The CCD camera - and only the CCD camera - explains why amateurs with three inch scopes can beat professional images of twenty five years ago taken with ten tonne telescopes and huge photographic plates. Amateur mounts and optics have advanced a little. The CCD camera is the revolutionary. I'm simply re-iterating advice given to me by Ian King around seven years ago and in those seven years I have never for one second doubted the quality of the advice.

 

Give me an astrophoto budget like yours and I would start with a CCD camera (probably an Atik because they work) and build from there. An HEQ5 will cope admirably with a small refractor and then you just need... a small refractor. There's plenty of choice.

 

Sure, I'm wedded to CCD imaging. But the best advice I can give you is, forget the DSLR stage if you mean business. Nobody could be less IT orientated than I am (OK, my wife is worse!) but if I can get round the IT side then anybody can.

 

Olly  http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2277139556&k=FGgG233

From what Russ is saying he already owns one more cameras which would probably see him through the first 12 months of the hobby (and also the steepest part of the learning curve). Olly is correct in that CCD's produce the best images but a decent CCD camera (and by that I mean large area CCD)(+ filters & wheel) will eat up the £3K budget and some! Many of us started with a humble DSLR and later moved onto better cameras AFTER grasping the basics.

EDIT- as for the choice of first scope I would initially go for something more like an 80mm F6 triplet. The shorter focal length would be more manageable and easier to guide, the faster F6 being being better suited to slow DSLR speeds. With a focal reducer/field flattener they are even faster. The triplet optics should have better colour correction than your camera lenses too.

[ollypenrice]

Olly, I don't doubt your statement for a minute; looking at some of your images you obviously know your stuff, however I am confused. Looking at the Blackwater Skies toolbox, using a sample scope of an Evostar 80 ED, my Canon 60d has a pixel size of 4.3x4.3, or 1.48x1.48 arc seconds per pixel. Looking at other "common" astro CCDs they do not seem to be that dis-similar:

Atik 383L+: 5.4x5.4 (1.86"x1.86")

Canon 60D: 4.3x4.3 (1.48"x1.48")

Starlight Express H694: 4.5x4.5 (1.56"x1.56")

Atik 490: 3.7x3.7 (1.27"x1.27")

QHY8 pro: 7.8x7.8 (2.68"x2.68")

So the DSLR seems to my untrained eye to have a pixel size on the same order of size as popular DSO imaging cameras, all of which are well within your 0.6 to 3.5 range you have worked with. I understand that CCDs are much better for other reasons such are Quantum Efficiency, cooling and no nasty IR filtering, but from a purely pixel size argument I remain confused. What am I missing?

You're not missing anything. You have it right, but you are looking at short focal lengths only, and accepting a high pixel resolution, higher then many UK imagers prefer given the seeing and the shortage of time. If you went for a longer focal length scope you wouldn't be able to bin up to compensate with a small pixel colour camera.

The Atik 490 in your list is an unusual beast in CCD terms. With its tiny pixels it is ideal for very short focal lengths, camera lenses, etc, and for extracting fine detail from them. 

Olly

[frugal]

Olly, in your opinion what would be a good CCD for an 80ED or a 200PDS (yes I know that is technicaly two questions as they are different focal lengths and different telescope construction)

Sent from my GT-N7000 using Tapatalk

[lensman57]

Olly, I don't doubt your statement for a minute; looking at some of your images you obviously know your stuff, however I am confused. Looking at the Blackwater Skies toolbox, using a sample scope of an Evostar 80 ED, my Canon 60d has a pixel size of 4.3x4.3, or 1.48x1.48 arc seconds per pixel. Looking at other "common" astro CCDs they do not seem to be that dis-similar:

Atik 383L+: 5.4x5.4 (1.86"x1.86")

Canon 60D: 4.3x4.3 (1.48"x1.48")

Starlight Express H694: 4.5x4.5 (1.56"x1.56")

Atik 490: 3.7x3.7 (1.27"x1.27")

QHY8 pro: 7.8x7.8 (2.68"x2.68")

So the DSLR seems to my untrained eye to have a pixel size on the same order of size as popular DSO imaging cameras, all of which are well within your 0.6 to 3.5 range you have worked with. I understand that CCDs are much better for other reasons such are Quantum Efficiency, cooling and no nasty IR filtering, but from a purely pixel size argument I remain confused. What am I missing?

I think the pixel size is the least of your worries. So is the theoretical  resolution of the scope, aperture and so on. I started imaging just over 6 months ago and what I have learnt is that the quality of your sky has much more influence on the final capture than all other factors put together. Given a proper astronomiaclly clear night without the dreaded LP and from a dark site even a humble DSLR  is capable of producing stunning results. Olly has a first class dark site with stable atmospheric conditions well away from LP and so on, hence he can be picky about all other factors involved in AP such as pixel size, LRGB imaging and so on. Personally speaking and imaging from my heavily LPed location in my back garden the only "stasisfactory" results that I have had so far have been made using a mono CCD camera, an Atik 314L+,  and NB filters in particular a 7nm Ha filter.  The rest of my rather extensive equipment including some very expensive RGB filters are now rather becoming  objects of self gratification. Unless I move my imaging gear away from the LP zone of Manchester  I would have a hell of a time producing the sort of capture that we see in the Deep Sky section of the forum, given that I like many others work some peculiar hours of the day and night,  that would not be a possibilty.

Merry Christmas to you all and clear skies,

A.G