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I have owned an 8" Celestron for 25 years and a couple of years ago upgraded my mount to an Exos-2 GOTO mount, love it, but until recently have taken only film pictures. I enjoy taken time exposures of nebula and star clusters etc. attaching my camera to the scope via a telextender thus allowing for wide angle shots. 2 years ago I dipped my toe into digital water and bought a £50 Orion planetary camera to get the feel of going digital. All well and good, I got some nice close ups of the moon and some fairly decent shots of Jupiter. However it is very limiting and I want to have the range I previously had with my old film camera. This is where I need some help, I want to restrict my budget to £200 but will go to £300 if necessary. I realise that spending over a £1000 is not unusual, but way too much for my limited means. Don't mind buying second hand if that will provide the camera necessary, but prefer a lower cost new one. So which camera do I buy and can I assume I can get a 'T" ring, if that is what they are still called, to attach it to my scope? I already have Registax and Photoshop for processing. I have only just started looking but it seems that digital cameras with detachable lenses can be very costly. Any advice would be really appreciated as I can't afford to make a costly mistake and buy an unsuitable camera.

Just one last thing. I have read comments from other members describing how they got their pics and have not a clue what they are talking about, it's a foreign language to me. Dark screen, subtract this and that, I have no idea. I am getting too old to learn all this new complicated stuff. Can I not just buy an ordinary digital camera, screw it to my scope and set the time exposure? Or is that too simple and just a pipe dream? It's just that I look at their fabulous pics and go green with envy and wish I could take pics like that! But surely I can with the right camera? At the moment I get the impression I need a university degree to get a good pic of say the Orion nebula. With film it was so easy, just had to get the scope correctly polar aligned and select the right exposure time! But my very  best film pic of Orion I used to be so proud of is as nothing compared to modern digital pics of same, the fine detail now shown is simply stunning!

thanks.

Keith

Edited by Moonshed
Needed to add I need to keep it simple

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Hi moonshed, if you look through the imaging forum you will no doubt see that a lot of members use Canon DSLRs. The EOS 1100D is a very popular choice. It has live view and is fully controllable with a number of programs. EOS Utilities is free from Canon, but a bit limited, I have heard people use Backyard EOS. If you want something a bit more technical, then Astrophotography Tool (APT) is a very good programme. It is free for the basic version, but if you subscribe (which is really cheap) then you get extra content and notification of updates as they become available.

You will need a T-ring which won't come with the camera unless you buy second hand from an imager. T-rings are available from FLO and nosepieces if you need one too.

I think Amazon may still sell the 1100D new, otherwise it is secondhand. You can also get the camera astro-modified by Cheap Astrophotography (the IR filter is removed to allow more of the red end of the EM wavelength through.

HTH:smile:

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Yup. +1 for Canon and the 1100 is a good choice. You can check your local camera shops or fleabay. 

Best of luck and enjoy  

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Just an after thought. You've come to the right place. Ask questions and you'll get great answers. 

Welcome and be ready to have fun learning.

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MPB is a good place to look for bargain secondhand.
If you take your time, excellent low count Canons like the 600D come along for around just over 200.

If you want full frame thats a different ball game and likely out of your price range.
 

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Canon is often the direction that you will be told, Canon supply software to support the camera more for astrophotography more then others did (or do).

However I will say that for what you intend to do initally it likely is of little difference. Reason for this is that to get long exposures the "easy" option is to buy from Amazon a Remote Timr or Intervalometer and you set this to take say 20 exposures of 30 seconds with a 20 second wait period between each. Since you buy these for the camera, I have on on my Sony, it means that they all start the same.

So Canon, Nikon, Sony it is really your choice. One other aspect of Canon is that they are I believe the easiest on which the filter in front of the sensor can be removed and so allowing more wavelengths through, suggest you ignore trying this aspect, at least at first.  Depending on which bit of Norfolk you can have a look in London Camera Exchange in Norwich for a reasonable used item. Also there will be several shops selling used camera's. I would also half suggest a reasonable lens for wide shots - they are a good start point.

One aspect of a digital is the noise reduction feature. With this On the camera takes say a 20 second exposure, then it takes a 20 second "dark", it then subtracts the dark from the exposure (more or less) and then writes the result to the memory card. So a 20 second exposure is at least double the time. And in the time the chip gets hot so needs to be allowed to cool. Simple "cooling" is do nothing for the "exposure" length, which is now 40 seconds.

Reason I say this is that on an Intervalometer you will have to set: A 20 second expoure, then a Wait time of at least 60 seconds = 20 for the noise reduction and 40 for the cooling. It begins to get a bit complicated.

I presume that from the film aspect you are aware of T-rings, and spacers and likely flateners ???

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Many thanks to all for your help and advice. I have taken note of what you have said and have ordered a Canon EOS 1100D second hand body for £136 together with a T ring for £13. Also bought a QUMOX intervalometer for £18 inc. postage. So in total only cost me £167, well inside my budget. So many thanks.

Is there anywhere where I can get advice on how to use it for time exposure astrophotography? Stuff like 20 thirty second exposures with a 20 second interval, or whatever. It all seems so foreign at this stage and I am unsure how to get to grips with it. I appreciate time and practice with trial and error is one way, but I just need a start point to get me going.

BTW What are flateners? Not come across that before.

Thanks again, you have all been most helpful

Keith

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I have a Canon 450D - same sensor, I think.

Start with ISO800 and 30 or 60 second exposures and work from there.

I find that 60 is a number of subs  of that sort of lengths that gives usable results.

Deep Sky Stacker is free and will make initial processing easy for you, although your images will look very dark before stretching the detail will be there.

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I think I have found a solution to getting started. I went on Amazon and ordered a book, "Digital SLR Astrophotography " by Michael Covington. It concentrates on the Canon EOS so will be ideal for me. I chose this book because 25 years ago when I first started out taking film photos I bought his book "Astrophotography for the amateur" and found it invaluable, I still have it. Looking forward to getting started and a new challenge.

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As you have mentioned, the standard in astrophotography took a staggering leap forward when cameras went digital. With this leap came more exacting demands on the optics. So what is a flattener?

It's a correcting lens which will give point like stars over a large sensor when, without it, you would get seriously distorted stars towards the edges.

Olly

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On ‎05‎/‎08‎/‎2016 at 00:03, Moonshed said:

Just one last thing. I have read comments from other members describing how they got their pics and have not a clue what they are talking about, it's a foreign language to me.

I am just starting out myself (this forum has been a great help). Numerous people have suggested I get the book "Making Every Photon Count" by Steve Richards as it is the definitive guide. I ordered mine this morning, so hopefully some of the 'foreign language' will be cleared up.

Best of luck to you.

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Is there another description for flateners as I can't find them? Are they called coma correctors by any chance?

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yes you might want a coma corrector BUT! as you have already used your film cam successfully there is no point in getting one right away: it has nothing to do with going digital, but with the optics of your scope in general, and good ones are expensive. In other words: try replicating your film results first, ask questions here, and take it from there. PS regarding iso and exposure settings: settings with iso lower than 400 on a canon will not lower noise, so the lowest useful iso setting is 400. 800 has a bit more noise, but is still ok, id use higher settings only for very dim objects.

Use the longest exp possible without elongated stars, just like with your film cam. hpoe that helps. Best results use computer software for processing multiple images but if you can make it with film you can make it with digitals without the fancy stuff , at least as a start.

 

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On 05/08/2016 at 00:03, Moonshed said:

I am getting too old to learn all this new complicated stuff. ... But my very  best film pic of Orion I used to be so proud of is as nothing compared to modern digital pics of same, the fine detail now shown is simply stunning!

Hi Keith. Don't put yourself down! Take things slowly. You'll be surprised how quickly you pick things up. You will soon surpass your old film images.

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My understandi8ng is that coma correctors and field flatteners do similar but distinct things.

Lenses come to focus across a curved surface causing stars away from the centre to be slightly out of focus (in a round way), the field flattener corrects for this so the focal plane is flat. You can also compensate by focusing on a star at the 2/3 point of the field instead of the centre.

Parabolic mirrors have a similar issue but it is manifested as a 'smearing' distortion of the stars towards the edge of the field. This 'coma' is corrected by (you've guessed it) a coma corrector.

So both lenses aim to achieve the same end of pin-sharp stars across the field, but as the faults they correct are subtly different they are not constructed the same way (but try finding a diagram of how they are constructed and work on google!).

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I did not see anybody asking what mount you will be using... so.. what will you be using? People are mentioning 30 - 60 seconds exposure with a DSLR , but your mount has to be able to do this...

I think you would be better of taking a whole lot of shorter exposures like 5 seconds or even less and stack them in one of the free stacking programms to start with.

If that works out ok, you can try longer exposures and will understand the tracking capabillities with all the consequences of your mount better.

Immediately going for 'long' exposures is a quest for frustration and that will be easily found.  Shorter and more exposures will  be far less problematic and will give you nice results which will stimulate you to try out more.

just my € 0,02

Waldemar

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1 hour ago, Waldemar said:

I did not see anybody asking what mount you will be using... so.. what will you be using? People are mentioning 30 - 60 seconds exposure with a DSLR , but your mount has to be able to do this...

 

Waldemar

I have been using the Exos 2 mount for the last year or so which I find does a brilliant job. I have not done long exposure with it, just 1200 frames or so of video for example using an Orion planetary camera and all well and good. I have got the Polar alignment and tracking down to a fine art over the years, and with some very basic equipment too. In the old days It would take 15 min exposures using film to capture the Orion nebula, seems ridiculous now. So looking forward to getting some good deep sky images. The old ways stood me in good stead, taught me patience and how to find my way around the night sky long before computer guided GOTO mounts came on the scene. Would I go back? Not a chance in hell, bring on the technology! I have Registax and Photoshop on my laptop.

Edited by Moonshed
Typo
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Before spending any more money get this book

https://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html

Steve is a moderator here ("steppenwolf") and his book is pretty much the beginning imager's bible. Read it through once, then again. Have a think, read it a third time and come back with any questions, we'll be happy to point you in the right direction, though you're off to a head start with a S/H Canon. If you have the budget consider having it modded to remove the IR filter, as it will block a lot of the all important Hydrogen Alpha line.

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1 hour ago, Moonshed said:

I have been using the Exos 2 mount for the last year or so which I find does a brilliant job. I have not done long exposure with it, just 1200 frames or so of video for example using an Orion planetary camera and all well and good. I have got the Polar alignment and tracking down to a fine art over the years, and with some very basic equipment too. In the old days It would take 15 min exposures using film to capture the Orion nebula, seems ridiculous now. So looking forward to getting some good deep sky images. The old ways stood me in good stead, taught me patience and how to find my way around the night sky long before computer guided GOTO mounts came on the scene. Would I go back? Not a chance in hell, bring on the technology! I have Registax and Photoshop on my laptop.

Hi Moonshed, I am from that era too... started in the early eighties with astronomy and somewhere mid eighties I tried imaging on film. Skipped that very fast because of the pain in my neck it caused me... guiding through an eyepiece was not my favorite thing...
so, I was very happy with the promise of CCD camera's when they came available. Not even close to what is available nowadays, though.

The Exos will give you a hard time with longer exposures, because of big periodic errors, so don't be disappointed. Just take more shorter subs as I said before.

15 minutes total for M42 is not that much at all, even not now! To get real detailed data you need a lot more then 15 minutes. 

Glad you have found your way with technology! It is great fun! and that is what it's all about, what a great way to enjoy retirement!!

 

Waldemar

 

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12 hours ago, Waldemar said:

 

Glad you have found your way with technology! It is great fun! and that is what it's all about, what a great way to enjoy retirement!!

 

Waldemar

 

Hi Waldemar,

Yes, I agree, it's a great way to enjoy retirement! I can stay up as late as I like and next day spend as long as I like on processing. It's been a hobby of mine since I bought my first 4" reflector  back in the 60's, it was a special promoted by Patrick Moore on the Sky at Night  programme. That amazing man got me hooked on Astronomy and It is something I just love. It's not just about getting that great image, it's also about just looking through the 'scope, or binoculars, at the amazing night sky. It gives me an amazing feeling just looking at it.

Keith

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