Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: JohnH on Dec 20, 2018, 13:32:04

Title: My first attempt at LRGB imaging - M45
Post by: JohnH on Dec 20, 2018, 13:32:04
I took this image on the 12th December with a monochrome ZWO 1600 Pro attached to a very cheep 50 mm camera lens f1.8.
(https://i.imgur.com/IFO6iPh.jpg)

(My first attempt at uploading an image so I hope that I have done that correctly!)

I can see a lot of the problems!
1) No nebulosity - I only dared to take 5 second sub images because of light pollution. I will have to be braver.
2) Awful star shapes. As I said, it was a cheap lens. I plan to make a cardboard aperture (say f8) to put over the front of the lens. This will also help:
3) Focus. I am going to make a mask to help with that.
4) Processing. I used Astro Pixel Processor and a bit of Photoshop Elements. I am at the start of the learning curve (I have some Astrophotography Actions to help with the basic nature of Elements).
No doubt that there are more.

I just hope that as I continue to image it will show up as improvements. It's not that I have done it well (I haven't) it's just that I have done it at all.

John Hulme
Title: Re: My first attempt at LRGB imaging - M45
Post by: Carole on Dec 20, 2018, 14:36:17
Well this is stage 1 of a long learning curve.

You got an image - great.  What was the mount?

Not sure where you live, but if the LP is bad, then there are LP filters you can buy, but not sure how you would attach it to a camera lens.

Carole
Title: Re: My first attempt at LRGB imaging - M45
Post by: NoelC on Dec 21, 2018, 14:25:06
Well done John.
Put your analyst on danger money.

Will watch your progress with interest.

Noel
Title: Re: My first attempt at LRGB imaging - M45
Post by: JohnH on Dec 21, 2018, 15:05:39
Thank you both for your advice!

I am probably being over concerned about light pollution - I back onto a school playing field. Is it OK to do Luminance with an LP filter? I have one for visual observing but it is too thick to go in the filter wheel so I would need another one.

John
Title: Re: My first attempt at LRGB imaging - M45
Post by: Carole on Dec 21, 2018, 15:44:51
You can add a LP filter in front of  luminance filter if you think it is necessary.

Carole
Title: Re: My first attempt at LRGB imaging - M45
Post by: The Thing on Dec 21, 2018, 17:50:48
Hi John,

You should see my first attempt at M45! Yours is a masterpiece by comparison. Is this a single frame or were you able to stack some frames in APP? I have and use old Pentax lenses and get very passable results when I get the focus right, the expensive one was £20! I made a tiny Bahtinov mask for my lens' out of A4 binder cover plastic (nice and thin, easy to cut) and bluetac/gaffer tape it to the lens front, you could do that with an LP filter as well if it's 2" and that would stop the lens down as well. Then you get LP with your all your filters.

My best lens effort was with a Canon 1000d modded with a 55mm Pentax lens on a tripod - I captured Orion with Barnards Loop using lots of 20S exposures and manually reframing a couple of times. It was from a dark site in the depths of winter :)

Good luck and persevere!

Duncan
Title: Re: My first attempt at LRGB imaging - M45
Post by: JohnH on Dec 21, 2018, 18:05:24
Thanks Duncan,

I took 30 subframes of 5 seconds each and stacked in APP. I have since been channeling my inner Blue Peter - I have made a cardboard cap with a 3.5 mm hole to stop down to f8 and I have made a "Y" mask to try to help focus (lazier than a Bhatinov Mask). It seems to me that focus is by far the most fiddly part of the whole exercise (ie nigh on impossible!).

My theory is that cardboard should be OK, astronomy tends to be a dry weather hobby most of the time.

John
Title: Re: My first attempt at LRGB imaging - M45
Post by: The Thing on Dec 21, 2018, 18:17:33
A tip I got from MarkS a long while back was to tape the focus ring either side and mark on side with close lines and the other side with a single line to use as a focus index then tape the ring to the  to the lens to hold it there.