Imaging Scope

[johngccfc]

I don't have a scope at the moment, but lets assume I do, for visuals, whats a good imaging scope.

The scope i have in mind for visual, a dob, doesnt track well for imaging.

Thanks

[nmoushon]

The scope isnt the most important part here its the mount.The typical minimum beginner imaging set up is HEQ5 with an ED80 with a reducer/flattener and a DSLR camera. With that you can get on average 90-120 sec subs.

[swag72]

What are you looking at imaging? Solar system stuff or DSO's? I ask as the requirements are very different.

If you are interested in DSO AP, the above suggestion is a good one. Can I suggest that if you are wanting to delve into DSO AP that you buy the book 'Making Every Photon Count' that is available in the book section of the FLO website. It's an excellent book that is something of an imaging bible, will save you a few headaches along the way.

[x6gas]

If imaging DSOs then I'd recommend a short focal length, low f ratio refractor. The short focal length gives you a wide field of view (many DSOs are surprisingly big!); the low f ratio (under 7) means that you'll need relatively short exposures and a small frac is light so is not so demanding on your mount and doesn't need collimation.

[ronin]

AP = Expansive.

So on thast basis, A good apo refractor on an HEQ5 or EQ6.

If I were going for it then I would at then time look to the US and one of the WO GTF-102's and I see you can get from there a WO GTF-81 still. Overall the cost would be £1500-2000 by the time everything was taken into account.

TS do some nice looking apos at £1000 Photoline Triplet 80/480, Photoline 102 Triplet £1500. Also several others from APM on their site so worth a look for information. All costs are simply approximate and I took equallity for pound to euro, seemed easiest.

Other then a refractor there are Mak Newtonians and RC's, again generally costly but as said AP = Expensive.

[Scott]

If you want to be in the top 5-10% of the field then yes... a.p. can get VERY expensive. If however, your happy to settle for very-extremely good then it doesn't have to cost ridiculous amounts. Look at some of the work Steppenwolf, Quartermass and others have done with a skywatcher frac (around £500) on a descent skywatcher mount (heq5 or neq6, not sure) then you will see what can be achieved for around £1500, I know it's not peanuts but when you concider some folk use fracs in excess of £20,000 on £5000-£10000 mounts it's not so bad.

[ollypenrice]

HEQ5, ED80, autoguider and then whatever camera. DSLR is cheap but limited, CCD far better but more expensive. I agree with the thrust of the advice so far. Steve's book would be a good idea, though, as Sara said.

One thing to watch out for, though, is that tracking and guiding are the hard part and get a lot harder as the focal length goes up, so start at short FL. (Preferably under 700mm and certainly under a metre.)

Olly

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

[johngccfc]

Thanks all,

I've ordered the book.

Your comments have made me have a rethink;

I was going to get a light bucket dob with GoTo, and as an afterthought considered getting a refractor for AP

I'm wondering now whether to tone down the dob slightly, get a EQ6 that can take a newtonian or a refractor. This way, I can use either scope with a single mount. I was trying to work out a way that they could both be on the mount together, as this mount can take it, but my newtonian would be too heavy to share it.

Regarding solar system or DSO? it hadn't occured to me that there would be a difference.

Anything WO is a little out of my league at the moment.

Sara, your images are extremely impressive.

Re: Steppenwolf iamges - stunning.

Below is the results of a little homework, a mount, a reflector, and a few choices of refractor. Your comments are appreciated.

Once again, thanks for all your contributions;

**************************

Skywatcher AZ EQ6-GT GEQ & Alt-Az Mount

£1,349.00

Payload Capacity: 18kg for imaging and 25kg for visual

**************************

Skywatcher Explorer 300P-DS OTA

£598.00

18 kg

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Skywatcher Evostar 80ED DS-Pro

£349.00 OTS

£459.00 (outfit) - any good ?? - all pieces necessary ?

8 kg

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Skywatcher Evostar 100ED DS-Pro Outfit

£625.00 (outfit) - any good ?? - all pieces necessary ?

15 kg

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SkyWatcher Equinox-80 PRO F/500mm Fluorite ED APO Refractor OTA

£532.00

[bogdog]

how about this?

http://www.firstlightoptics.com/skywatcher-mounts/skywatcher-heq5-pro-synscan.html

Price: £759.00

http://www.firstlightoptics.com/skywatcher-quattro-f4/skywatcher-quattro-f4-imaging-newtonian.html

Price: £398.00

[swag72]

The Skywatcher 100ED is a far slower scope at f9 than the 80ED at f7.5 (both native speed) - This is important for AP, you want the fastest scope you can get. If you are looking at using the 80ED soley for imaging then you only need a set of scope rings for mounting purposes. Your mount suggestion is a good one. What camera are you planning on using for AP? I ask as if you are going to be using a DSLR that has a large chip, then you will want to factor in a reducer / flattener as well at some stage. This will speed the scope up a little (especially beneficial for the DSLR's) and also will help deal with the corners on the large chip.

If I was setting up again, I'd be looking at a move straight to a CCD camera. I think that the mono camera's while more expensive initially as you need to buy a filter wheel and filters, they are far more versatile and I think far easier to process than DSLR images.

But you will get others who say differently. It's a hard decision to make, but the book will hopefully help you make a more informed choice.

Thanks for looking at my images

[johngccfc]

bobdog - i did look at that scope but thought it might be a comprimise on both counts.

feel free to correct me

[johngccfc]

sara, my camera is a 550D with is crop h sensor. even with magic lantern i dont think it has shutter open times reqd for AP

i understand how a dedicated ccd would be better. which would u be looking at?

thx

[swag72]

Something like the Atik 314L+ is an excellent camera to go with an 80ED scope. Many people use them to good effect. Of course, you'll need to decide between mono and One Shot Colour (OSC) if you go down the CCD route. CCD's are not cheap and the sensor size in the Atik 314L+ is very small in comparison with the DSLR. If you look at the following http://www.12dstring.me.uk/fov.htm you can put in different permeations of scope and camera and get a combination that you like.

The Quattro noted above is a well considered scope for imaging. It's just a different type of scope. A refractor such as the 80ED is by far and away the most plug and play option that you can get. No collimation required and easier on the mount. But many use the Quattro - Have a look in the imaging section, people generally say what kit they have used to capture their images.

[Scott]

I think (with the emphasis on the I) that the only reason.. or at least the main reason we use dslr's for ap is cost. Unfortunately it's a very big reason as there's quite a difference between £300-£400 and £1000-£2000. so that said, I'll be sticking with dslr for the time being.....after all, it's not like they are terrible

[johngccfc]

@sara - that'll teach me to ask someone who has a Takahashi refractor. i think i'll need to be starting a little more humbly than that. at least it gives me something to be studying around. thx

@scott - what bothers you the most about 'having' to use your dslr?

as in, what do you feel you're missing out on,or where/how do you feel you end up compromising?

thx

[swag72]

I started out with a DSLR too and a skywatcher scope. In fact I am still using my original HEQ5 and hope to do so for a while yet. Noise became an issue for me with the DSLR, hence I changed to a CCD. I accept that cost is an issue for many, AP is an expensive hobby and is full of compromises.

[atmenterprises]

sara, my camera is a 550D with is crop h sensor. even with magic lantern i dont think it has shutter open times reqd for AP

i understand how a dedicated ccd would be better. which would u be looking at?

thx

You could buy a $20 intervalometer from Amazon, set your 550D to bulb mode then set the exposure times on the intervalometer. That's what I do on mine.

Or maybe look at BackyardEOS, a piece of software that may control your exposure times via USB cable.

[ollypenrice]

CCD is far quieter and way more sensitive than DSLR. Mono CCD also allows you to combine narrowband data with colour, often with spectacular results, this being my favourite example;

On the left, the object just isn't there! A run through an Ha filter makes so much difference. But, yes, you get a big bad chip with a DSLR and that has its plusses. I might be inclined to say that nobody goes from CCD to DSLR but, just today, one of our most experienced and expert guests has just told me that this is exactly what he's doing...

Olly

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

[Scott]

John, I wouldn't say it bothers me, it's just that ccds are dedicated astro cameras where as dslr are, if we are honest, designed for terrestial work. to be fair, there are plenty of mods available for dslr's. put it this way, I'd rather be using my dslr than not imaging

[bogdog]

bobdog - i did look at that scope but thought it might be a comprimise on both counts.

feel free to correct me

i can't as i have never used either,only selected those as a cheaper option for you ,and the fact that the quattro is "supposed" to be ready for dslr imaging

(taking away the focussing issues of many other scopes) i use a nikon 3100 with a skywatcher 130 and it will only come to fucus if i use a barlow with it

as i dont fancy butchering the scope to move mirror forward

and i think with the evostar (i might be wrong here but somebody will correct me) you are into more expense with a field flattener

[johngccfc]

>> Mono CCD also allows you to combine narrowband data with colour, often with spectacular results, this being my favourite example;

>> A run through an Ha filter makes so much difference.

A physical filter or software?

Olly

http://ollypenrice.s...39556&k=FGgG233

>> Mono CCD also allows you to combine narrowband data with colour, often with spectacular results, this being my favourite example;

Is a Mono or Colour CCD the smart choice?

(my obvious guess is colour - in fact I wonder there is such a thing as Mono)

>> A run through an Ha filter makes so much difference.

A physical filter or software?

Thx

[ajohnson]

Skywatcher AZ EQ6-GT GEQ & Alt-Az Mount

£1,349.00

Payload Capacity: 18kg for imaging and 25kg for visual

**************************

Skywatcher Explorer 300P-DS OTA

£598.00

18 kg

Noooo! I have a 300 PDS on an NEQ6, roughly the same capacity at the Alt-Az, it is first and foremost a stunning visual scope and I love it to bits, but you may want to bear in mind that with rings and a Losmondy mount plate (don't even consider a vixen plate for this tube!) the OTA weighs in at 26kg plus accessories. This being my main scope I have used it for imaging on the NEQ6 but it struggles with images over 60s on anything other than a still night. With my polar alignment as close as I can get it and PEC training I can push up it to 120s but that is stretching it (although I have some lovely images of M17 at 120s with this beastie). A slight breeze has the OTA dancing and humming on the mount like a Canary on a caffeine overdose, again for visual this is ok because a light touch with a finger damps down the tube, but it's no good for imaging. Last night we had winds up to maybe 9mph (a light breeze) I rejected over 70 of my 30s shots of NCG7250 due to star trailing.

Which brings me to my interest in this thread. Although I've had great results with it, I know the 300PDS is eventually going to drive me mad using it for imaging with my Canon EOS350D so I'm looking for something physically smaller and lighter that I can eventually put a guider onto. I've been looking at Celestron C8s, C9.25s or maybe a C11 if I can get a good 2nd hand one. These appeal because with a focal reducer they can be dropped to f6.3 but also in "Standard" rig they make nice compact visual scopes that can easily be bundled into the car and taken to the dark sites that I currently drag the 300 to. On the other hand I'm a bit of a Luddite and have seen a few f4 Skywatcher Quattros and Altair Astro 8" Newts for sale at a good fraction of the price of a C8 and must admit they appeal both as a known quantity (I like Newts and don't fear collimating them) and from the perspective that within my budget I could buy one of these plus a half decent guide scope & camera.

However,I have a concern that having gone to all this expense I could still end up cursing on nights where there is only a light breeze that one in three or four shots is in any way usable and I'd be happier using my dosh to buy a small frac or SCT (plus mount) or a biggish Dob to do some stargazing while the big Newt is tied up imaging. I don't have room (or the budget) for an Obsy and I don't expect to image during the equivalent of Hurricane Sandy, but I'm guessing that a slightly longer f4 scope is more tolerant of a light breeze than say a compact SCT at f6.3 does anyone have any experience here?

[ollypenrice]

>> Mono CCD also allows you to combine narrowband data with colour, often with spectacular results, this being my favourite example;

Is a Mono or Colour CCD the smart choice?

(my obvious guess is colour - in fact I wonder there is such a thing as Mono)

>> A run through an Ha filter makes so much difference.

A physical filter or software?

Thx

All digital camera chips of any kind, including DSLRs, are mono. To get colour you put filters in front of them, usually red, green and blue. A DSLR has each pixel under its own filter in a Bayer Matrix of RGGB. The other way to do it is to leave the chip unfiltered and shoot through R, G and B in turn with a 'mono' camera. So far there is no great difference between them.

But... now you want to pick out subtle detail in H alpha emission, say. Ha is red, but if you put an Ha filter in front of a colour filtered chip only one one pixel in four will get any light. The B and two G filters will block the red.

Ha (or 0III or any other narrowwband filter) is a physical filter controlling what goes onto your chip. It has nothing to do with software, though combining it with a colour image requires some learning in the software later.

Many people think that shooting in one shot colour is easier than in RGB with a mono camera. It simply isn't. It can be the other way round. Post processing one shot colour images can be very tricky on occasion. There's a good phrase; complexity brings control.

Olly