M42 cont. . .

[stardust steve]

Hi. Finally got a chance to have another go at collecting some more data for M42.
Very windy conditions and DSS rejected 30 mins of data (30 x 60 sec)
Anyway, here is the total of all my accepted DSS stacked data.
1 hr and 21 mins of 60 secs subs.
Flat and Dark frames unmatched to light.
500D un mod- eq3 ra tracking unguided- swed80 pro.

Having and fun and challenging time learning how to process with out going too heavy handed as always lol

[Larryp]

Lots of detail there, Steve!

[ourkind]

Wow Steve you must be stoked with that! What a great result, so much nebulosity! Awesome :thumbsup:

[HunterGeo]

Hi Steve,

A really great shot there. I am new to imaging through a telescope (I have been doing old-fashioned tripod-mounted astrophotography for a while, but only just bought a telescope). I have an ED80 like yours, mounted on a HEQ5 Pro GoTo.

I took it out the other night and couldn't get the camera to focus (I needed an extra centimetre between the primary and the camera, damn!) but managed a 30sec exposure of M42 and it was a lot smaller than yours, despite using the same 'scope.

Could you please explain how you constructed this image? How did you stack your exposures?

Thanks in advance,
Dave

[stardust steve]

Thanks Carlos. I was very happy to get all that extra detail although I still have not fixed the core:rolleyes: it's on the to do list :)

[stardust steve]

Hi Dave. I have attached 2 pic of the setup with the 500D. The first is with the focus tube all the way out. That pencil line you see about 20mm from the white housing is the point where it focuses. The second pic is a close up of the t ring screwed onto the 2"-1.25"adapter.
This image has been zoomed in and cropped therefore looking larger. Straight out of the camera, it is a wider field like yours.
Along with darks, I found flats really important as well. I took the flats at just before sunrise with a white tshirt pulled tight over the end of the ed80 held on with a rubber band. Used same iso and exp as lights and darks.
With DSS, I made sure I had the latest version , loaded up all lights, darks and flats ( although in this case the flats did not equal the same exp time as the lights and darks...still seemed to work) and stacked the images.
It took many attempts at processing and looking at it now, there are things I would like to improve on. Main things were brightness, contrast, levels, curves, saturation... The main ones really. Making small adjustments without blowing out the data you have. I find it really easy to push it too far and he result is less than satisfactory and often more data is required. There are some good tutorial on you tube about processing and thinking now, I don't remember exactly what I did ... I really should start taking notes.
I hope this has helped and the pics help and if there is any thing else I haven't covered, let me know and I will do my best. :thumbsup:

[stardust steve]

Here is the second pic. Doing it from my phone and the button are so small haha

[HunterGeo]

Hi Steve,

Thanks for those pointers.

Looks like I've got a lot of learning to do - I had not heard of DSS prior to your mentioning it. I googled it and see what it is for (I have been using Photoshop for stacking images).

What do you mean by flat and darks, though?


Have you done any imaging using a 2x teleconverter between the camera and the t-ring? It doubles your focal length, and I was using that with an old Nikon D60 and a 500mm lens (effective 1500mm once you consider the 1.5x focal length multiplier of the CX sensor inside the camera) - that was good for imaging NGC 1514 despite only using an ordinary camera tripod and no tracking. Check out the second-last photograph in this blog post: http://astro.huntergeophysics.com/catching-up-on-2012/

I am hoping that idea will work with the telescope as well, as the result will be a focal length of 1800mm!


Thanks again,
David

[stardust steve]

Hi David. I too am learning all the time, so much to take in. When combining darks with your light frames in DSS, the noise created from the camera is reduced. This works with images shot through lenses as well as through telescopes. And the result is, when it comes to processing, you can pull more data out of your images before the noise kicks in. Noise is the Bain of imaging, that's why people invest their hard earnt into cooled cameras.
The flats help remove the vignetting in the images. So by loading all your lights, darks and flats into DSS, it helps produce a cleaner image.
To take darks, it's simply taking a photo with the lens cap on for the same exp duration, same iso as your light frames were.
For flats, all I do is rubber band a white cotton tshirt over the end for your dew shield or lens hood, at dawn just before the sun rises so the sky is evenly illuminated, and take your pictures once again with the same exp and iso.
There a a few tutorials about using DSS and processing images on the net and YouTube is a good place for them.
I have not used a 2x on my camera lenses. When it comes to imaging through my telescope, the increase in focal length greatly increases any misalignment there is the polar alignment ( with my eq mount).
I have used two 2x barrows that gave me 4x my focal length on the moon and planets which works very well. Although with me, I realized a good quality Barlow is needed.
The idea still works on the telescope, it's just from my experience, I will need to guide with another camera and scope or use off axis guiding. Every single one of my images at present are unguided. I kind of enjoy the challenge at the moment unguiding gives. One day soon I hope to get some more equipment.
There are some absolutely magnificent images taken with just tracked camera and lens ( wide fields) out there and it can make for a refreshing change. That's how I started, buy using my camera and lens on my eq3 tracking mount, getting the basics of alignment and everything else, and seeing how long I go go before trailing started to occur. Much fun to be had.:)
I hope some of this helped.
Steve

[HunterGeo]

I get ya. Thanks for explaining all that to me. :)