Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Carole on Apr 12, 2010, 21:39:17

Title: Any tips on imaging the Sun?
Post by: Carole on Apr 12, 2010, 21:39:17
After Fay handed me the solar scope to take to Kelling Heath it was a glorious day on Saturday and so I thought I'd have a go at imaging the Sun.

All I managed to get was a lovely pink disc with the webcam and a white disc and "squashed prominence" with the SC3.

I couldn't seem to get any features at all.  It's annoying as I had the Sun on the chip for hours, had plenty of time to twiddle with the controls/focus/shutter speeds etc etc, but just couldn't seem to show any features.

Taken with Phillips webcam

(http://carolepope.amateur-astronomy.org/_wp_generated/wpeff6000a_0f.jpg)

Taken with SC3 modified webcam

(http://carolepope.amateur-astronomy.org/_wp_generated/wp432efabf_0f.jpg)

Just wondered whether any-one had any thoughts/advice on technique or were my cameras not really suitable for the job?

Carole
Title: Re: Any tips on imaging the Sun?
Post by: JohnP on Apr 12, 2010, 21:46:13
Ask Fay!
Title: Re: Any tips on imaging the Sun?
Post by: Carole on Apr 12, 2010, 23:11:41
Already did, but couldn't fathom anything out I wasn't doing except she was using a different camera to me.

Carole
Title: Re: Any tips on imaging the Sun?
Post by: mickw on Apr 13, 2010, 06:48:06
Perhaps overexposed ?

I'm guessing you're using the same cameras and settings that you use for DSOs
Title: Re: Any tips on imaging the Sun?
Post by: MarkS on Apr 13, 2010, 08:06:17

Carole,

Looks both overexposed and blurry to me.
1) Turn down the gain or increase the shutter speed
2) Check the focus
3) Check the camera is not clamped wonky

Mark
Title: Re: Any tips on imaging the Sun?
Post by: Carole on Apr 13, 2010, 09:06:44
I'll give it another go.  But I had the shutter speed turned up to maximum as anything less was obviously over exposed.
I was wheeling the focus in and out all the time trying to find the right point.

Gain was moved up and down to various positions as were all the controls.

I'll give it another try another day. 

QuoteI'm guessing you're using the same cameras and settings that you use for DSOs
Definitely not the same settings, but the same webcams. 

Carole
Title: Re: Any tips on imaging the Sun?
Post by: Mac on Apr 13, 2010, 14:45:46
QuoteI was wheeling the focus in and out all the time trying to find the right point.

Ah ha, there lies your problem.
you are trying to focus the telescope into the camera,
As the camera is being used as a focal projection (I presume. Camera held to eyepiece)

when you press the shutter the camera then tries to focus iteself.

When i took some images throught the solarscope I did the following.
0) Fit adapter (see below) and remove the camera
1) Look through the solarscope and focus the image so you can see it. (glasses on if needed)
2) using something like this attach the camera.
(http://www.astro-engineering.com/ETX/Resources/at.jpeg)
3)take the photo, the camera should be able to focus without any problems.
4) if it cant reach focus, either switch the camera to macro mode, or slowly slide the camera away from the eyepiece and try again.

Mac
Title: Re: Any tips on imaging the Sun?
Post by: Mike on Apr 13, 2010, 15:41:01
You are way overexposed. You need very short exposure times.
Title: Re: Any tips on imaging the Sun?
Post by: Rocket Pooch on Apr 13, 2010, 16:10:54
I'd give up, I feel that way quite often.....
Title: Re: Any tips on imaging the Sun?
Post by: Carole on Apr 13, 2010, 18:19:15
QuoteYou are way overexposed. You need very short exposure times.
Mike, I know this is over exposed, but I just could not seem to change it whatever I did with the controls, (except lose it altogether).  I adjusted the frame rate to the fastest which brought it down a bit, and brought gain and brightness down.

Mac I wasn't imaging with a camera held to eyepiece, I was using a webcam.

QuoteI'd give up, I feel that way quite often.....
Yup tried again today, but gave up.

Thanks anyway every-one, but I have given up for now as I won't have the solarscope after Kelling Heath. 

Carole
Title: Re: Any tips on imaging the Sun?
Post by: MarkS on Apr 13, 2010, 18:31:20

In that case we should give it a try at Kelling Heath.
Title: Re: Any tips on imaging the Sun?
Post by: Carole on Apr 13, 2010, 19:41:40
Good idea Mark, better bring my XP laptop then and my webcam.

Carole
Title: Re: Any tips on imaging the Sun?
Post by: Fay on Apr 13, 2010, 19:57:33
My prominance one came out white, probably to do with the brass wheel position you have to have for the prominances