Long Exposure For Deep Space Objects

[Zakalwe]

In my opinion, auto-guiding is one of those things that make a quantum difference to AP (the others are CCD imaging and access to plentiful dark skies). I say this for a number of reasons:

• You will be able to expose for much longer, and go much deeper.
• You will have fewer lost sub-exposures
• Your data will be of higher quality
• Your final results will be easier to process. Processing is hard enough to learn without trying to learn it with poor quality data

Again, personally, i think that learning auto-guiding and getting the kit should happen as soon as possible. Yes it's another layer of complexity, but once you suss it you will wonder why the heck you didn't do it sooner.

[laned]

Wow just refreshed after my last post! bam loads more infos! you guys are awesome

Ok So GOTO is the way to go. Just to confirm ive got my facts correct. This is what Ill need to take images of deep space objects.

1. Choice of Scope is 200PDS

2. Choice of mount is HEQ5 with GOTO

3. Some small scope to use for guiding (Do i still need this if im using GOTO?)

4. A Laptop (this I already have) (Do i still need this if im using GOTO?)

5. DSLR Choice is Canon 60Da

6. Cables to connect the small guiding scope to mount and laptop (Do i still need this if im using GOTO?)

[laned]

In my opinion, auto-guiding is one of those things that make a quantum difference to AP (the others are CCD imaging and access to plentiful dark skies). I say this for a number of reasons:

• You will be able to expose for much longer, and go much deeper.
• You will have fewer lost sub-exposures
• Your data will be of higher quality
• Your final results will be easier to process. Processing is hard enough to learn without trying to learn it with poor quality data

Again, personally, i think that learning auto-guiding and getting the kit should happen as soon as possible. Yes it's another layer of complexity, but once you suss it you will wonder why the heck you didn't do it sooner.

Zakalwe, im still a little confused around the auto-guiding terminology. Is that using the Laptop,small scope and cables? Using GOTO would not be auto-guiding?

[laned]

GoTo is a major bonus for imaging. I'd call it nearly essential. Why?

1) You are often imaging things that have never been seen in any telescope by anybody. (They are too big for large scopes and too faint for small ones but the camera can see them over time. That is the whole point of imaging.)

2) Time is incredibly precious and when you have a clear sky window you do not, not, not want to be faffing about finding things.

3) Taking cameras out and putting eyepieces in and then the reverse is an absolute no-no. You muck up you critical focus, there are implications for your flats, your camera orientation, etc etc. Don't do it.

4) Things go wrong, you lose your guidestar, the mount moves the scope, but you want to get back to your target. Go To. (Or you could take out your camera, lose your critical focus, put in an EP, struggle to re-find your target, replace your camera, re-focus it... oh look, it's dawn!) I do this for a living. I use GoTo...   

You seem serious about getting into this so think 'autoguider' from step one. It is a part of imaging life. You need it. It is orders of magnitude cheaper than buying a mount capable or working unguided at a serious level.

Don't spend a penny (on kit that is   ) until you have read Steve's book. Lots of things in imaging are very counter-intuitive and once you've spent it wrongly you've spent it.

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2266922474&k=Sc3kgzc

  WOW at your pics Olly! I really am serious about getting into this, I feel as if its almost calling me .

Ok I see i was looking at this incorrectly. I assumed GOTO and autoguide where mutually exclusive, so I can use GOTO and use autoguiding at the same time. Just to clarify im on the same page here, autoguiding can be done with GOTO or the little scope and a laptop (with software to control the mount etc) ?

[Zakalwe]

Zakalwe, im still a little confused around the auto-guiding terminology. Is that using the Laptop,small scope and cables? Using GOTO would not be auto-guiding?

GOTO just points the scope at the right part of the sky.

The mount will then track, but tracking (unless you have a very expensive mount-think £5K+) is imperfect. Sub-exposures will be limited to something like 2-3 minutes

Autoguiding uses a separate optical system and camera to "lock on" to a star and then issue commands when the mounts drifts a bit.

I meant it when I said to buy that book and read it. I wish that I did when I started as it would have saved me £hundreds

[laned]

GOTO just points the scope at the right part of the sky.

The mount will then track, but tracking (unless you have a very expensive mount-think £5K+) is imperfect. Sub-exposures will be limited to something like 2-3 minutes

Autoguiding uses a separate optical system and camera to "lock on" to a star and then issue commands when the mounts drifts a bit.

I meant it when I said to buy that book and read it. I wish that I did when I started as it would have saved me £hundreds

Ok thanks for clearing that up for me. I have ordered the book. Hope it gets here fast . Is there a name for this seporate optical system? Id like to look into the costs and understand it a little better.

[malc-c]

My set up is observatory based.  I used a PC running EQMOD and CdC for telescope control, PHD2 with the ST80 guidescope fitted with a QHY5 camera for guiding, APT to control the D400 DSLR.

[Zakalwe]

Ok thanks for clearing that up for me. I have ordered the book. Hope it gets here fast . Is there a name for this seporate optical system? Id like to look into the costs and understand it a little better.

Normally its a separate telescope mounted on or alongside the main scope. The ST80 is frequently used. I used to use a modified finderscope to great effect.

The other main way of doing it is an Off Axis Guider. That system uses a prism to divert some of the light cone from the main scope into a guide camera. Both systems have their pros and cons. The modified finderscope is probably the simplest, easiest system to start with.

[wuthton]

If cost is a problem there's nothing wrong with an Eq5 pro mount with an 80mm refractor. Great beginner setup and if you buy used equipment you'll get your money back when you want to upgrade.

£500 could see you up and running if you already have a dslr.

[lensman57]

GOTO every time for me- imaging time is too precious.

To run EQMOD & do auto guiding you'll need a netbook or laptop. Personally I don't bother with EQMOD- I like the simplicity of the handsets. 

I have found that with 3 cycles of 3 star alignment and then the polar align routine even my HEQ5 pro puts the target within the small sensor of the 314L+ or 428EX,  nine out of ten times and quite often  dead center. As yet I am not clear if EQMOD can be useful  for someone like me who has to take the mount and the scope in and out every session.

A.G

[laned]

I’m unclear on quite a few things, can’t wait for "Make every photon count" to arrive . Someone else told me that I am reaching to high with this setup, they suggested that it would be useless for anything else. Such as looking at the planets and moons in our solar system. I am of course interested in making observations of that nature to but if that is the case I'm happy to save up for another scope to accomplish both. Can anyone confirm?

[MND]

You could do what I did.

Buy Every Photon Counts. Ignore what it says and decide to do your own thing. Spend a load of money then find out it wont work. Read the book again and start from scratch!

[Zakalwe]

Why cant you waot for the book to arrive?

If theres anything that Ive learned in the 5 years since I started this mental road into AP is that a healthy, well developed level of patience is an absolute must!

[swag72]

Read 'Making Every Photon Count' .......... think about what has been written in the book very carefully ............ read it again ..................... make a plan of what you want to image and what kit you think you will need. Maybe read the book again ................ make sure that you really understand what you are buying and why you need it.

Imaging is a frustrating hobby and one that requires a great deal of patience and understanding. When it goes well it's a real buzz, when it doesn't ....... to say that it's annoying is an understatement.

Have a look in the imaging section and really look at peoples images and be realistic about what you want to achieve. People often list their kit that they used. You will often see that people use a shortish focal length refractor (such as an ED80) - with good reason these scopes have been the basis for many people's imaging rigs. Many DSO's are really quite large and so a shorter focal length works well. Have you looked at a field of view calculator with your proposed combo to see that it really is what you want (http://www.12dstring.me.uk/fovcalc.php).

The refractor is the easiest of all the scopes to use. Unlike the larger reflectors, it won't act as a sail and so ruin subs. You want to keep as much data as you can. You need a rig that is rock solid as you will be wanting to get long exposures - When I am imaging in narrowband for example I always do 30 minute subs. So nothing needs to move in my case for 30 minutes.

So, read the book and then think about whether your proposed kit really is going to give you the sort of images you are after.

Hope that has helped.

[Redbird48oo]

I found out buying the book Every Photon Counts, will cost you a lot of money, LOL it did me. The book is one of the best I have ever read. Sure glad I have a very very very understanding wife.

[laned]

Thanks all for the advise . Its been very helpful, and I can see me becoming quite an active user in these forums. I'm looking forward to it

Zakalwe, me saying I cant wait is just another way of saying I'm very excited. I will of course wait for the book, read it  and make an educated decision on what I purchase . I'm sure i'll make mistakes but without them we can only learn so much.