RCC - First DSO attempt - Forums

Topic starter

Dec 15, 2016 · Edited: Dec 18, 2016

Hi this is my first go at DSO. My equipment is less than ideal I know but from what I may eventually get something acceptable. I had a hard time focusing. The only thing I knew to do was to view the object through the camera's view finder and it was really hard and as you can see not very successful. I think a Bahtinov mask may prove helpful.

Using a Pentax K100D hand-me-down camera I took 6 30 second exposures at ISO 1600 using auto WB and only 2 were even remotely worthwhile. Less than ideal seeing conditions... a bit windy with high thin clouds and a very bright moon not too far off. I don't quite understand how to align and stack very well yet using AS2! or Registax. I've done very little post processing with Photoshop (just a little reduction in exposure to get he sky more black and I think I may have tweaked the histogram a little. This is a single image not a stack.

Looking for some criticism and tips for improving next time time.

Cheers!
Steve

setheddy

Mar 6, 2017

Hi Steve,

Looks like a god start. The first thing to remember is that this is a very hard hobby and it pays to fallow the same process every time. I even make sure to plug everything into the exact same receptacle every time, usb, st-4, 12v power etc.

For the equipment you have I would:

1.) Make sure you fallow the most strict alignment routine your mount has to offer. Add as many reference stars, or fallow the polar alignment routine, and then make sure you are as closely aligned as your mount can be.

2.) Focus on bright star preferably with live view if your camera has this function. In live view, center the bright star and then zoom in as much as possible on the live view screen. you might not be able to zoom in all the way because when you go to adjust the focus the star may move out of frame but zoom in as much is possible and where you can still see the star when making focus adjustments. Do your best to focus the star this way.

3.) I would not use a Barlow lens. This doubles your focal ratio and slows down the scope requiring longer exposure so gather the same data. Crop the image later if you want to zoom in.

4.) Now you are as close to "polar aligned" as possible and in focus slew to a bright star near the target you want to take a picture of. Select the star name on the handset and let the telescope slew to the star. Center the Star and sync the mount on that star. This should give you a little better tracking on the target you want to take pictures of.

5.) Slew to the target you want to take pictures of and frame the shot. I take test images with the ISO all the way up then adjust the mount until I have my target framed. Set the ISO to 1600 like you did and take the longest image you can. Buy an intervalometer if you can to take multiple images without needing to touch the camera and take images longer then 30sec.

After you take your first image view it and zoom in on a star. you want it to be as round as possible. if they are very oblong reduce the exposure time, but if they are nice and round increase the exposure time. You want to take the longest image you can without seeing tracking error (Streaking Stars)

6.) Take as many images as you can (I would not take less then 8 images but with 30 sec exposures I would take 100 or more re centering when needed) the exposure times should be exactly the same so you can stack them.

Download DSS (Deep Sky Stacker) and process the images. you can find tutorials on that on Youtube.
Good Luck!

setheddy

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Tony Hallas

Mar 6, 2017

Hi,

   What you need more than anything is MORE EXPOSURE … this is the brightest object in the sky, so you must do whatever it takes to get more of it recorded.

   Without getting complicated … EXPERIMENT. All the best imagers have done trillions of hours experimenting to test the limits of the equipment, the sky, and your processing techniques. Being a novice, this is even more important than anything else. It is how you will learn.

   You can read about imaging techniques in many places … just Google the question and be prepared to be inundated. But it's trying all this out without fear of failure that will bring progress.

   Hope this helps,

       Tony

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