DSLR Imaging - Now I See Why It Is So Difficult

[MikeP]

Many writers on this forum indicate that DSLR imaging has a long steep learning curve and a great deal of patience is required. As a complete newbie no telescope yet (due to arrive Thursday) and no DSLR, I found it hard to visualise the problems. Surely you just attach the camera, point the scope, take a number of exposures, stack them (whatever that means) and then manipulate the images on a PC.

It seemed many other newbies have a similar aspiration, so I attach the following links to a series of 3 articles that have given me a dose of reality and may set expectations for others.

http://cobalt.golden.net/~kwastro/images/Pulsar_Spring_2005.pdf

http://cobalt.golden.net/~kwastro/images/Pulsar_Summer_2005.pdf

http://cobalt.golden.net/~kwastro/images/Pulsar_Fall_2005.pdf

I take my hat off to those of you who have already mastered these skills and produce the beautiful images you share with us. Perhaps you'd be so kind as to have a look at the articles and indicate how close to reality the procedures he describes are.

Mike

PS The cobalt.golden.net site is a bit slow

Mike

[Caz]

Very helpful links there Mike.

I don't know whether you have seen Rus's work, but incase you haven't here's a thread you may be interested in, and something to whett the appetite. I believe Rus used purely a DSLR... 8)

http://stargazerslounge.co.uk/index.php?topic=9550.0

Caz

[MikeP]

Thanks Caz - hadn't seen that thread before. Beautiful images.

Mike

[Ant]

I think that the author of that article has made it overly complicated.

There are losts of things that he lists that sound complicated but you would do as a matter of course in setting up for visual as well as imaging.

To take pictures (at least to start with) you don't need all that Rubbish, I use a HEQ5, 300D, T ring, 2" adapter and a IR remote for the camera. This is, of course, in addition to the scope.

I do not need an autoguider, laptop, dew rings, GOTO... etc etc...

Now I am fairly happy with the results that I get, but they could be a LOT better, if I had GOTO i'd find the object quicker and get more RAW frames. If I had an autoguider I could expose for longer.

If I had everything hooked up to the laptop and then go in doors for a cup of tea. But these things just make life easier (when they work).

So to recap, it isn't easy, but the learning is fun. You can start imaging with an EQ3 and almost any scope if you have a DSLR. To be honest you could start with an EQ1 (as a driven camera platform) and DSLR and standard lens and get some nice results.

Most of the really hard work is in the processing at the end, it can make or break an image. Oh and getting focus with a DSLR can be a right bitch, but it's all worth it when you get your first set of images.

As your images imrove, you'll buy more equipment and it will end up like the article BUT 75% of what he lists will be a normal list of actions that you automatically do every time you set up.

Ant

[Vega]

I have a problem with flat frames in that I just cannot be bothered! How on earth to you focus your DSLR (via scope) to the same focus in a twilight sky as you would during your imaging of light frames?

Even if you master that you have to mess about getting the right exposure time for a RAW flat etc

I guess I'm not quite a hardcore imager yet. Time will tell. In 6 months time I'll probably be set up with an auto-focussing, auto guided, dew controlled, temperature adjusting, permanantly polar aligned observatory!

[MikeP]

Thanks Ant and Vega, that's the sort of feedback I'd hoped for. I'd begun to think it was going to be beyond me.

I've ordered an EQ6 Pro and Explorer 250 from FLO, scheduled for delivery tomorrow. Imaging is on hold till I can find my way round the sky without using the GOTO (other than as a learning / checking aid), so with luck the standard set up procedures will become less of a mystery.

I hope you don't mind me asking, but I do have a couple of questions on Ant's response.

• 
  [li]I'm guessing the T ring screws onto the camera and the 2" adapter screws onto the T ring and then attaches to the focuser on the telescope (or an eyepiece?).[/li]
  [li]I'm also guessing the IR remote allows the camera to be adjusted without touching it - does that include focussing or is that only done with the telescope?[/li]
  [li]For example, I'm thinking of buying a Canon 400D - how would I focus it? Would I just look at the display on the rear of the camera and eyeball it based on the diffraction spikes the article refers to, using the telescope focuser to focus?[/li]
  

Sorry these are such basic questions.

Mike

[Kaptain Klevtsov]

Thanks Ant and Vega, that's the sort of feedback I'd hoped for. I'd begun to think it was going to be beyond me.

I've ordered an EQ6 Pro and Explorer 250 from FLO, scheduled for delivery tomorrow. Imaging is on hold till I can find my way round the sky without using the GOTO (other than as a learning / checking aid), so with luck the standard set up procedures will become less of a mystery.

I hope you don't mind me asking, but I do have a couple of questions on Ant's response.

• 
  [li]I'm guessing the T ring screws onto the camera and the 2" adapter screws onto the T ring and then attaches to the focuser on the telescope (or an eyepiece?).[/li]
  [li]I'm also guessing the IR remote allows the camera to be adjusted without touching it - does that include focussing or is that only done with the telescope?[/li]
  [li]For example, I'm thinking of buying a Canon 400D - how would I focus it? Would I just look at the display on the rear of the camera and eyeball it based on the diffraction spikes the article refers to, using the telescope focuser to focus?[/li]
  

Sorry these are such basic questions.

Mike

The T ring fits to the 2" adapter and usually stays there. The assembly fits to the DSLR like a lens would, then plonks into the 'scope's focuser.

The remote usually does either shutter only (Nikon etc) or you can use a computer to shoot a sequence of shots of different lengths (Canon). With the Canon you can adjust stuff via the lead using the laptop.

Focusing is a pain and can only be done using the 'scopes focuser. DSLR focus, or whatever its called for the Canon will "talk you through it" to get the best focus available.

HTH

Captain Chaos

[MikeP]

Thanks Cap'n,

The penny has now dropped. I had not realised that "DSLR Focus" is a piece of software. The following link explains how it is used as you say to "talk you through the focussing".

http://www.dslrfocus.com/

I'm happy now and I'll concentrate on visual once my telescope arrives and the obligatory two weeks wait for clear skies has elapsed.

Mike

[Vega]

Mike, I use the Canon EOS 400D and am delighted with it. Fantastic big LCD screen for reviewing and of course all the great features of the renowned 350D. Lens cleaning is a nice added feature too. For focusing you can use the review tool and on the LCD, zoom in to the image (surprisingly far in!) to see the roundness of stars. You then keep taking photo's and moving the telescopes focus tube slightly each time until your happy. Failing that use a laptop and review the full monty. Either way it's a little time consuming but essential.

The only niggle I have is that the viewfinder is very dark (for night-time photo's) making it very hard to center any faint DSO's you plan to image (leave alone focus it!). I've heard this is the case with most DSLR's though. Again, nothing good old trial and error/ LCD reviewing doesn't fix.

I use the T-ring/adaptor as described. I also use Canon RC1 infa red remote release. Wonderful to use and dirt cheap! The sensor is on the front of the camera but the remote still works from a wide, side angle so no "hand in the way" problems there even when doing widefield photo's. You can remotely use the camera via a laptop too. With seperate software and a modified serial cable you can even specify a bunch of multiple long bulb exposures, set her off and go have a cup of tea!

Sorry for rambling, but as ur looking at the same camera as mine thought I should comment

Matt

[MikeP]

Matt,

I don't think providing me with a detailed explanation of the pros and cons of a camera I'm thinking of buying can possibly be construed as rambling. Thank you very much for taking the trouble.

I used to enjoy photography years ago before being caught up in the rat race (loved my Canon A1 - hope the ******* that stole it treated it well), so looking for something versatile. Someone recommended the Canon 5D to me today. From the specs, it seems to be a lovely camera but the price puts me off - Mrs MikeP would want many pairs of shoes to compensate. Just wondered if anyone on this forum owns one and uses it for astrophotography and if so, does it help with the problems Matt describes. I believe its viewfinder view should be brighter.

Anyway, enough of dreaming - thanks again Matt.

Mike

[SteveA]

Mike,

Thanks for the links..I found these articles pretty interesting!

I'm just getting in to DSLR imaging after having previously used an SC1 modified webcam. I want to improve the quality of my DSO images and going the DSLR route seemed like the most cost effective way of doing it. I got a really good deal on a Canon EOS350D, at only £350 quid it seemed like a no brainer...

[Ant]

The real difference between the two is the FOV. For Example, M42 doesn't look great on a Toucam chip (due to the narrow FOV, but looks great on a DSLR).

But it's easier to get and stack multiple images from a toucam.

For small objects, the toucam IMO still does very well.

But of course with the toucam you need the laptop as well...

Ant

[Astronut]

That was an interesting read

I'm a complete novice at astrophotography so this may seem like a daft question:

The author is using a refractor but I can see obvious diffraction spikes (as seen when using a typical newtonian) in the star images on the images of M42 and M45 in the first 2 linked articles.

The author mentions (in the first article) creating an artificial spider vane by using string to create a 'cross mask' on the front of the tube as an aid to achieving critical focus.

Does this mean the author left this artificial spider vane on during imaging and, if so, why? :?

I've noticed these 'newtonian' diffraction spikes in some other refractor images elsewhere. :? :?

[MikeP]

Astronut,

In the absence of a DSLR and a scope, I haven't even graduated to novice yet.

I'd assumed that diffraction spikes would be present when using a newtonian (which is what I intend to use) and hence no mask would be required. As you say, there are spikes in the author's images, supposedly taken with a refractor? My best guess is that he used a mask to focus and either forgot to remove it or chose not to, to avoid disturbing the telescope.

OK experts - do you get diffraction spikes with refractors?

Mike

[Kaptain Klevtsov]

Two easy ways to get diffraction spikes with a refractor.

1) Add sticks or wires across the end of the 'scope.

2) Put them on during processing in Photoshop. (Noel's actions has spiking tools)

Captain Chaos