Deep sky astrophotography

ThatDrGuy

Hi all,
The skies finally cleared ! So I tried to make the most of it. Here are some images I took last night. Im slowly getting to grips with the process:


Andromeda


NGC1973 The running man nebula



M33 The Triangulum Galaxy (aka Pinwheel Galaxy)


Tips/Comments Appreciated

Popoutman

Good images.

Info on the images? subs x length, flats, darks, camera, scope? Guided or not? Which mount?

cfuserkildare

Hi,

ThatDrGuy, just a quick comment regarding the pics you have above,

Best to use a more open aperture and slightly shorter shutter speed, images will be sharper as slight movement can be seen in the pictures.

Also try to use the most up to date lenses for Astrophotography because older lenses do not have such good quality anti reflection coatings on the rear elements.

Excellent pics by the way.

peterako

Hi ThatDrGuy,

GREAT images! 'Love the one of Triangulum!

I hope you don't mind if I join you on this journey.

I changed my scope last year to get into DSLR Deep sky.
Got a chance to try on the 13th and just processed images today.

I'm an absolute, ABSOLUTE, novice at this but would love to learn....

I only took a few snaps for each of Andromeda and Great Nebula in Orion to get familiar with the mechanics.
Results below are processed in DeepSkyStacker and GIMP. (after converting the tif's to jpeg).

Exciting 'new' world!





Clear Skies,
Peter

ThatDrGuy

Thanks for all the feedback.

Popoutman: Andromeda was 8 x 30 second exposures, 5 x 30 dark
Running Man 30x30 exposures 10 x 30 dark
M33 was 30x30 exposures 10x 30 dark

I didnt use any flats ( I don't know how to make them) Next job is to try and figure out a method of producing them. Scope is Nexstar 11gps using its internal guiding system. All stacked in Nebulosity and played with in photoshop. Camera is cannon 350D unmodified.

Cfuserkildare : I know very little about the process yet. All were captured at iso 800 - im not sure about appeture/shutter speed. The camera is connected directly to the scope with just a focal reducer between them.

Peterako : The more the merrier. Thats a really good image of andromeda - can see the dust lanes very clearly. Orion was my first target last month as well.

It is an exciting new world. If only there wasn't a sodium street light 6 feet from my set up. Anyone have ideas for reducing the light pollution ? Would a filter help ? Would the council shade the light ?(cant afford any brown envelopes )

premiercounty

nice pics guys

what set ups are you using there Peterako?

I am trying to set up to start deep sky imaging
I have an 8" Meade SCT (old 2080 model)
and a Canon 350d unmodded plus all the connectors etc

The SCT is fork mounted and has RA tracking motor only.
I know I will have to accurately balance and very accuratly polar align (using wedge) the set up to get any half decent images.
Has anyone any experience using a set up like this for Deep Sky ?
And can I expect any reasonable images ?
I see on a lot of forums that an equatorial mount seems to be de riguer for deep sky imaging ?

thanks

dbran

premiercounty wrote: »

The SCT is fork mounted and has RA tracking motor only.

It is strange that it is on a fork mount but only has RA tracking motor only as it seems for a fork mounted scope, it would be incapable of tracking without the dec motor moving.

Is it possible that you are operating in "polar mounted" mode and not in "alt- Az" mode? Does it have an autor star? Check the manual.

Regarding deepsky imaging, you can get quite good images of the brighter objects via alt az and taking shorter exposures and stacking them.

If you want to go deeper then 1-2 minutes then you will need to have an equitorialy mounted scope or purchase a wedge. This adds an extra level of complexity to the whole setup and you will definately need to ensure that you are accurately polar alligned and that the mount is capable of staying centred on the object for that period of time. There will be inaccuracies in the drive which will become apparent over the length of the exposure greater then a few minutes (periodic error) so you will then need to have a mount that is capable of remembering where there errors are or getting a guide scope and camera.

My advise is image in alt az until you are bored with it and then get a new scope that is properly equitorially mounted and forget about getting a wedge.

Regards

dbran

peterako

Thanks ThatDrGuy!

premiercounty wrote: »

....

what set ups are you using there Peterako?

....

Not TOO different from yours:

Orion Optics f4 8" Newtonian (Probably a 2003 or so model)
Old Celestron CG5 mount with RA tracking only
Canon EOS 400D (un modified)

Processing:
DeepSkyStacker
GIMP

I didn't Polar Align very accurately. In fact not well at all.
BUT I will when I get comfortable with the overall process.

I'm very happy using my EQ mount.....but then I've never tried any other

Clear skies!
Peter

premiercounty

Hi dbran,

The scope is old and does not have autostar
old school astronomy for me !
Yes, I use an equatorial wedge to align with the pole star and set the RA and DEC circles to find objects generally or starhop
Works fine for observing, and I have used a modded webcam with some success for imaging planets and moon.
Using this method, yes there are inaccuracies, but I have managed to keep objects within the view for over 5 minutes by being reasonably accurate with the polar align.

Your advice is much as I was thinking myself, the EQ mount would be the way to go, but I think Id like to tinker away at my set up for a while and see how it works out

Thanks

Tzetze

Nice work guys!

ThatDrGuy wrote: »

I didnt use any flats ( I don't know how to make them) Next job is to try and figure out a method of producing them.

ThatDrGuy, for flats what I do is take a white t-shirt. Stretch it over the end of the scope so there are two layers across the opening. Stretch it out so there are no creases/wrinkles and secure it with a rubber band. Point it at a light source (I hold a torch in front of it). Put camera to lowest ISO, change to AV setting and take about 30 shots. It's important that you don't change anything in your image train from when you took your light subs. Keep focus, etc. the very same.

This should produce an evenly illuminated image. There are dedicated flat-field panels available for the job, but in the meantime I find the t-shirt method does an adequate job.

I tried some DSO work with my new ED80 on that clear night also but the fog soon killed my plans. I did manage to get some solar work on Sat afternoon though. Here's my first Sol attempt...

(click for larger)

kopite davo

amazing shots, but what do these figures mean???

Popoutman: Andromeda was 8 x 30 second exposures, 5 x 30 dark
Running Man 30x30 exposures 10 x 30 dark
M33 was 30x30 exposures 10x 30 dark


i have a canon 60d and have always wanted a telescope.
i would love one that can take shots like these. what price bracket are you talking for scope to take shots like this?

Tzetze

kopite davo wrote: »

amazing shots, but what do these figures mean???

Popoutman: Andromeda was 8 x 30 second exposures, 5 x 30 dark
Running Man 30x30 exposures 10 x 30 dark
M33 was 30x30 exposures 10x 30 dark


i have a canon 60d and have always wanted a telescope.
i would love one that can take shots like these. what price bracket are you talking for scope to take shots like this?

Dark exposures are stacked and averaged. The master-dark file is subtracted from each of the light shots before they are stacked to help remove unwanted noise. There are other calibration files that can be taken also - flats, dark-flats, bias.

Canon DSLRs are regarded as the best DSLRs for AP, so you're off to a good start. For decent budget scope, mount and accessories for AP, you'd be looking at around ~€1500 - although you could get a better deal second hand. The most important part of the kit is a good equatorial mount that is able to handle a large payload and remain rock steady.

If you're serious about starting down the AP route, then the best piece of equipment you can buy to start off with is this book. It is aimed specifically at the newbie unlike most other books that assume the reader already has their kit and basic know-how.

HTH.

kopite davo

thanks for the reply. so out of interest are the exposures 30 secs long to stop blur or is it because the its the cameras exposure limit. would using bulb let you use longer exposures with a star tracker ???
i would defo go 2nd hand with equipment. there are a couple of scopes for sale on adverts. need to do more research before buying.
is there any clubs around kilkenny area??? googled but couldn't see anything.

ThatDrGuy

Exposures are 30 seconds long because 1:) limits of my camera without bulb adapter cable 2:) limit of my exposure time without doing a wedge polar align with my setup

With a good equatorial mount you can expose much longer and with a tracker - a piggey backed scope connect to computer you can expose all night if you want to.

Great photos.

I'd absolutely love to get into AP. It seems like such a fantastic and fulfilling hobby. I'm going to start saving for all of the gear now, and hopefully I'll be able to join you with photos sometime in the far, far future.

dmcdona

Nice images folks. The colours seem a little "off" but then I'm comparing your images to likes of Rob Genler et al.

When I took my first images, I certainly did not produce anything like these.

Photography in general is a minefield. Astrophotography is doubly so. So these images are really atestament to the blood, sweat and tears you folks have put into them.

A regards tips, there's probably hundreds I could give you, but here are the most important ones:

1. Decide what kind of astrophotography you want to do
2. Work out what you can afford
3. Go back to 1

When you gone through the above iteration a few dozen times, stick to your budget.

How much does a really good AP setup cost? Depends. I'd reckon the likes of Anthony Ayiomamitis, Rob Gendler etc, are well into high 5 figure figure sums - possibly 6 figure sums.

How much does an adequate setup cost? Possible a few grand, especially if you go second-hand (and there's plenty good equipment about).

I'd better stop there or I'll be going for the day...

For more info, www.irishastronomy.org is a good spot to ask questions and get reasonable answers.

Cheers
Dave

kopite davo

just need cloudless skies. we can wish !!!!!

peterako

Cloudless skies!!

Had planned to observe Mars last night but the seeing did not seem great so dug out the DSLR...

Orion towards the West....showing the terrible light pollution over Athlone...



Same direction, but some stacked and processed shots to bring the pollution down (DSS and IrfanView):



And my first attempt at M51



Get out there folks!!

Peter

ThatDrGuy

Thats really good. How many exposures did you do ? I had a look at m51 last night - its on my must image list. Might save it until I get a decent
equatorial tracking set up though.

peterako

Thanks

M51...

Only a few 1 minute shots and a few 1 minute 'darks'.

I did some at ISO 400, 800 and 1600 and stacked accordingly.

I think I'm a bit out of focus....have not Polar Aligned well.....need to take flats/darks/more shots....

Not sure if I have the patience for this though.....
(And if I did I definitly would be divorced!!)

BUT.....it's strangly addictive :rolleyes:

Peter

Tzetze

I finally got my guiding setup working pretty well although once in every full dec gear rotation my dec line shoots off the graph and returns back to the origin again. This will give me only a max of 7 minutes or so exposures with some careful timing to avoid the spike. Must be a bit of dirt in the dec gear somewhere. That's a clean-up job for cloudy summer days.

Anyway, when I was happy enough with guiding, I did a few test shots on M51. Only took 4 exposures at 300s. No flats and used about 30x240s darks I had in my library (must take some longer darks in the fridge soon).

Anyhow, here's 20 minutes of data on M51 (note the tight stars! :pac: ).

Canon 450D, SW ED80 Pro, CG5-GT. Didn't use a barlow so the object was very small in the field of view.


Edit: Oh, I should add that for guiding I use a LIDL bought Bresser skylux 70/700 refractor which I eventually plan to upgrade to a SW ST80. Guiding camera : Meade DSI II. Software : PHD Guiding.

ThatDrGuy

Thats really good Tzetze. Is the set up long ? I have a parts for a guided set up but until i get a camera that can expose > 30 seconds and an EQ mount doesnt seem any point. Does your mount have PEC ? Took this image of christmas tree cluster last night. Here is unprocessed version:



As you can see light pollution is a major issue. I lose all the nebula's colour when I have to downshift the red levels.

Tzetze

ThatDrGuy wrote: »

Thats really good Tzetze. Is the set up long ? I have a parts for a guided set up but until i get a camera that can expose >30 seconds and an EQ mount doesnt seem any point. Does your mount have PEC ? Took this image of christmas tree cluster last night. Here is unprocessed version:
As you can see light pollution is a major issue. I lose all the nebula's colour when I have to downshift the red levels.

Thanks a lot TDG

These light pollution filters are supposed to be great for the money, provided it's the yellow sodium lights that are causing the problem for you.

The setup takes ages. I spend about an hour pottering about getting all the bits assembled. Drift aligning then usually takes me about 30-45 minutes. Other people seem to be able to align much more quickly, but I just can't seem to speed up the process. Guiding requires a very accurate alignment so it's worth spending the time on it anyway. Then it's about another 15 or 20 minutes to do the two star alignment with three calibration stars. Then get the camera on and focused, get to the target, get guiding and start imaging. So, it's a good two hours before I start harvesting photons. Someday, I'll get an observatory built and won't have to go through the setup and takedown every time.

So, I'm out again at the minute. Guiding went much better tonight. The periodic spike seems to have vanished. Can't figure out what the cause must have been. Glad to see it gone though. Currently getting 10 minute exposures on M81+82, although the fog is threatening to spoil the session.

I've noticed how critical balancing the mount in RA and Dec is for guiding also. I had RA balanced to be slightly weight heavy for imaging in the East. (This causes the gears to bite as they have to push very slightly.) However, that inculded using a barlow but when it came to framing my target I realised that shooting at F15 with the barlow was making life too difficult, so I removed it and forgot all about rebalancing. This left the setup scope heavy. Anyway, while guiding I was getting this graph..


Quite spikey but not too severe and was still producing round stars at 10 minutes. However after doing the meridian flip and now imaging in the west, the gears are biting into and slightly pushing a scope-heavy setup and I'm now getting this graph...


I'm really delighted with this graph! It's about as good as I could hope to get. Very good results for a CG5 mount!

To answer your other question, my mount does have PEC but I'd need a GPUSB adaptor to do PEC training. They're not exactly cheap and anyway I think PEC is only necessary if tracking unguided so I don't think I'll bother with it.

What parts do you have in waiting for guiding?

ThatDrGuy

Thanks Tzetze, 2 inch light pollution filter ordered and on the way. That is some really steady guiding, cant wait to see the pic. For guiding I have a dovetail losmandy setup off my main OTA, a shoestring usb/serial interface from my pc, a wedge (which I cant manhandle), counterweights, modded neximage ccd for guiding and guidedog software. All I need is a small refractor and someone nuts enough to stand around in the cold helping me mount the wedge and EQ align.Plus an exposure cable for my 350D.And a light pollution filter. Otherwise a 10 minute exposure will look like the north on the 12th.

Tzetze

I'll be interested to see the results of your filter when you get to use it. I hope it does the trick for you.

So, I got last night's imaging finished up - that is to say it's at a stage where I'm reasonably happy with it. There was quite a bit of work involved in getting it cleaned up. The mist in the air as I was taking the subs didn't help matters.
Here's a sample of one of the subs...



In all I got 2.5 hours data and I was surprised that I didn't get better detail in the cigar galaxy but I guess that's just down to misty air and bad seeing. Hopefully a clearer night in future will yield a better result.

15x 600s subs
20 darks
40 flats
Stacked in DSS. Processed in PS CS5. Processing involved levels and curves adjustments, unsharp mask, high pass filter, star adjustment (size reduction and slight colour boost), noise reduction and gradient removal.



Hmm, in fact looking at them side by side, it appears that a single sub has better detail in the cigar galaxy than the final image. This is confusing!

ThatDrGuy

Thats very impressive ! Those stars are as sharp as they get. Detail is great.Im putting imaging on hiatus until filter arrives. The cigar looks like some core burnout from all the stacking. You can "fix" it in photoshop by making a smaller stack, using that as a layer and painting it onto main image : http://www.youtube.com/watch?v=YOPw3Pi8DkU&feature=youtu.be

Final orangified image : M3 Globular cluster

Standard Toaster

Hats off to ye lads, some fantastic pictures there.

Tzetze

ThatDrGuy wrote: »

Thats very impressive ! Those stars are as sharp as they get. Detail is great.Im putting imaging on hiatus until filter arrives. The cigar looks like some core burnout from all the stacking. You can "fix" it in photoshop by making a smaller stack, using that as a layer and painting it onto main image

I used all of that guy's other tutorials to do the processing, and I've used his 'fixing burned out cores' technique on an M42 of my own to good effect. I'll have to stack some much shorter subs of the cigar galaxy and blend them in. Hopefully this cloud won't stick around for too much longer and I'll get a chance to do it sooner rather than later.

That's a nice globular. The orange isn't too bad on it at all really. I have a thing for globulars! :pac: Some gradient removal might help clean it up.

ThatDrGuy

Tzetze, that light pollution filter you recommended was fantastic !
After the complex installation (involved chewing gum and duct tape ) I aimed it at m51. Barely had the camera on when clouds blew in. Below is the image, its a stack of 4 ( 4!) 30 second images.



Can't wait to try and get a decent run at imaging it.