Astroimaging - first year progress report

[broadsword]

As I've just passed the one year mark for my astroimaging efforts, and gone past the 100 posts mark, I thought I'd share my progress and as usual ask for some tips on going forward.

Below are efforts on the same object, M51, from around May last year and March this. I hope you agree some improvement has been made...the earlier one is from 11x60s ISO 1600 frames and the later from around 25x120s ISO frames, but I used the same equipment for both (C11 with f6.3 FR, NEQ6 mount, unmodded Canon 1000d). The big improvement seemed to come with the use of flats at the end of last year, and in the processing - DSS stacking and GIMP post-processing being supplemented by Harry's Pixinsight workthrough.

I'm now wondering where to go next. I've increased my typical fames to around 40, and am sticking with 2 mins at ISO 1600 as this is the longest I can go without guiding on my mount, and at lower ISO speeds fine detail is totally submerged in a noisy light polluted background. I don't really want to go to autoguiding due to the added set up/take down time involved (all equipment being stored in the garage), however I am planning to purchase a modded DSLR (450d) in the near future as fed up of losing all pinks in galaxies and nebulae being colourless. Also planning laptop exposure and focus control.

Any thoughts/suggestions?

Thanks,

Neil

[swag72]

There's a couple of things that spring to mind looking at your images and your write up;

1) Get guiding, that way you will get far longer exposures - This will make a massive difference to your data capture and the data you can get.

2) Learn about calibration frames - The vignetting on the first image could be dealt with and helped considerably with a set of decent flat frames.

[ultranova]

Hi Neil, just to add to Sara's good advice is In the end to get the fainter stuff you will

end up guiding and it dont take to long to set up once you get the hang of it,

Getting a modded slr will help alot for the fainter red stuff H alpha, but personaly

i would put all your resources into the Guiding you will be blown away by the diffence it makes,

Looks like you have made some nice improvments over the past year the m51 looks good

Paul

[iksose7]

Well, you have made great progress - that much is certain have to say i'm quite surprised that you can only get 120sec subs though. I would of thought the HEQ6 would be more capable? I know nothing about mounts though

[broadsword]

Firstly, apologies, just looked at the 2nd pic I posted and saw how horribly over stretched it was -the result of looking at the monitor this morning in a sun-filled room.....hopefully a better version below.

Thanks for the comments. I stick to 2 min subs not because the mount may not let me go longer, but because at 3 mins and above I get images totally washed out with orange glow in my location - it doesn't seem to pull out more object detail in preference to the background...

I will have a re-think about guiding. I was planning to get an ED 80 anyway as a scope for the larger DSO's like M31. I guess I can also use that to guide the C11...would it also work the other way round (ie. guide the ED 80 with the C11)?

[valefor]

although ed's have a great write up. maybe just get the guiding for now and practice with the scopes you have. you will still find some great results with what you got.

[swag72]

If you feel that the sky glow is stopping you going for longer subs - How about a light pollution filter? That will give you far longer exposures, more detail and processing will be easier as well.

[broadsword]

If you feel that the sky glow is stopping you going for longer subs - How about a light pollution filter? That will give you far longer exposures, more detail and processing will be easier as well.

Yes, I've thought of using an LP filter, but the C11 camera adaptor doesn't allow you to put standard 1.25 or 2 inch filters in the optical path. I've seen the Astronomik one though which goes in the camera, so I may get one and try it. Does an LP filter in itself drive up exposure times?

[swag72]

The Astronomik clip in filter for the DSLR is very good - It doesn't drive up exposure times as such, but just allows you to exposure for longer without blowing out detail and constantly fighting the orange glow.

[Gina]

That lastest image is a nice M51 - great detail

[broadsword]

Sara,

Didn't realise the LP filters helped with detail as well, think I will go for one for sure now.

Gina,

Thanks for you kind comments.....

[broadsword]

Blimey, I've just looked at my images again, this time on the company laptop in a hotel room, and all I can see is are great circles of lighter background on the later images - note, this isn't vignetting, but a radial mask i used to keep the background dark. Or so i hoped...

So, I'm shocked at the difference between what I see on an iPad screen (totally uniform background), my desktop monitor (bit of a faint hum) and the laptop (like a badly washed chalky blackboard). This is probably a new thread, but which do I trust? To get a good background on this laptop would need all the pixels reducing to about 5 and below, and everyone says go for about 20......anyone any tips on this???

[andyo]

Nice image I agree with the comments above guiding and a LP filter as Sarah mentioned the Astronomic Lp clip filter is a good choice and the Idas (not sure if they do a clip version).A finder guider system could be worth considering.