Photographing a solar eclipse?

[ianpwilliams]

Thanks. Now that I think about it, the way my setup is I usually only need to make a small adjustment to get Polaris in the right place when polar aligning, so hopefully my GOTO should get me to the right area, and I'm hopeful that it might be able to track the sun fairly well too. I'll get out there early and see how well it tracks. And hopefully focussing won't be too bad, just need to set the exposure to a point where things are clear enough to see details, and then focus.

Has anyone used those glasses from FLO? There are no customer reviews, and there are glasses out there that are a lot more expensive, but FLO never put a foot wrong in my opinion, so I ordered a pair. Also, I'm guessing that you could look at the sun any time with these glasses on, not just when imaging during the eclipse, but also when imaging a full sun, and basically any time you just want to have a look?

[carastro]

Change the tracking to solar tracking Ian.  

You won't get the corona unless it's a "total" eclipse, so you'll need to keep your solar filter on the whole time.  

Don't forget to watch as well and enjoy, don't spend all your time faffing around with the camera.

Might be a good idea to have a dummy run beforehand.  

Yes those glasses from FLO will be fine.  They are inexpensive.

I find the biggest chore with solar imaging is to actually get the Sun in the FOV as being so bright you can't look at it.  The shadow method gets you in the right ball park, but I still used to struggle even with that.

I bought something like this to help with lining the sun up, it is simple and works really well.  

Carole 

[ianpwilliams]

Thanks, my filter and glasses are on their way, so I'll do a dummy run before the day, because it would be nice to get a full sun anyway.

Do you have any links for that object?

Incidentally if a moderator could move this thread to the solar section then that would be good.

[carastro]

I think it was this company, but the small one that I bought looks to be out of stock, the others might be better anyway:

http://www.dynapod.com/dyna-hp1.html

[ianpwilliams]

Looks good.

[Vega]

For lining up, I find the finderscope shadow a good guide, just look at the finderscope's shadow (behind the scope on the floor) and move the mount until the shadow is as small as possible. The scope will then be pointing accurately toward the sun. KEEP THE FINDERSCOPE COVERS ON THOUGH OR YOU'LL BURN OUT YOUR CORSSHAIRS!) :-)

[LukeSkywatcher]

Change the tracking to solar tracking Ian.  

You won't get the corona unless it's a "total" eclipse, so you'll need to keep your solar filter on the whole time.  

Don't forget to watch as well and enjoy, don't spend all your time faffing around with the camera.

Might be a good idea to have a dummy run beforehand.  

Yes those glasses from FLO will be fine.  They are inexpensive.

I find the biggest chore with solar imaging is to actually get the Sun in the FOV as being so bright you can't look at it.  The shadow method gets you in the right ball park, but I still used to struggle even with that.

I bought something like this to help with lining the sun up, it is simple and works really well.  

Carole 

Never seen anything like this before. Care to explain how it works?. Im guessing its like a horizontal plum line kind of thingie.

[Carina Lass]

Remove the shadow from the pin on the circle and you're pointing dead on.

[carastro]

Never seen anything like this before. Care to explain how it works?.

The elastic goes around the telescope and you can pull it tight and hold it with the clip, then the  right angled plastic bit will be sitting squarely onto the tube once the elastic is tight.  Which also  means the round disc is square on.  Then you move the scope until you can't see the shadow of the spike (which sticks out front and back) on the disc.  Works really well, just don't have too much rubber spike sticking out forwards as it can be slightly bent, or at least mine was. Otherwise replace that with a cocktail stick or something.

This is on the same web page:

Carole 

[ArmyAirForce]

I made a solar filter for the finder too. It helps when imaging Sun spots to line up on them precisely when using a small sensor camera. The shield around the finder keeps the direct Sunlight away from my vision when using it. To line up on the Sun to start with, I just turn the scope until the scopes shadow on the ground is as small as it will go.

The Sun does change hour by hour, day by day. An Ha scope will show much more detail than white light using a solar filter, but even so, shooting the Sun several times across a day will show movement of Sun spots and the spots themselves changing shape and size. Sometimes the disc is very quiet, as it is now.....

....other times, there are huge spots visible.

I use a DSLR for the full disc, shooting 100 to 200 images, and then stacking them.

For close ups of spots, I use an ASI120MM planetary camera with a Baader Solar Continuum Filter to shoot a video of 4,000 to 6,000 or more frames, then stack the best 20% or there abouts, depending on seeing conditions.

Sometimes, you get a surprise transit....

[ArmyAirForce]

.......Does anyone have any tips for these parts?

My method of finding focus is as follows.....

When there's no spots, it is hard. I try to use the edge of the disc. Get the scope to rough focus, and then with a permanent marker, draw a line on the top of the focus knob.

Move the focus knob until the image just starts to look out of focus, and see where the pen line is and remember its position. Now move the focus knob back the other way, past where focus was better until it goes out of focus slightly the other way. Again, make a note of the pen line position.

Now sharp focus should be half way between those two positions. Wind the focus knob back half way, and that should be pretty close.

This next step is better done in the dark when you can get sharp focus on a star. ....

You could now make a small pen line on the focusser tube where it moves in and out against its holder. This pen line will allow you to put the focus back to near the correct position. This will probably only work for one eyepiece, but if you are using a camera, its focus position shouldn't change much, bar slight differences for temperature.

Hope that makes sense?!

[goodricke1]

Great shots Stephen http://www.cloudynights.com/public/style_emoticons/default/bow.gif
 

[goodricke1]

That should have been a

[Dave Lloyd]

My camera meter is still fooled by the sun even with a filter.

[ianpwilliams]

Thanks for the tips. A few more questions if anyone can help:

Do you know how much the shipping is for that device? It says "free domestic shipping", but they are in the USA, and the link goes straight to a PayPal payment.

Also, possible stupid question, but how big is the sun likely to be in my images with my setup?

I was hoping that I might be able to set the timer remote so that I could get a full sun with the moon nearby, then partial eclipses, then the moon at the other side. It's going to be a 90% eclipse where I am, and if I want to take shots of the sun ranging from totally exposed to 90% covered, then presumably they will need different exposure lengths won't they? The guy on the tutorial link says to go for 1/2500 to 1/400, but I guess that would be for a fully exposed sun, with longer exposures required the more the sun is covered?

And like I said before, the guy in that tutorial said "When you are happy take between 40 and 100 frames. I usually take 64 frames (or more if the seeing is poor – the idea is to have a final stack of around 60 frames)". I take it this is not necessary? Or do you indeed take lots of shots and stack them?

He also talks about taking Flats - is that worth doing?

Also, when you talk about Solar Tracking mode, how does that differ from the normal tracking mode (whatever that is, I'm guessing the normal mode is Siderail?)? I'm not actually sure what tracking mode my mount is in (I bought it second-hand).

[ArmyAirForce]

Have you taken a photo of the Moon with that camera and your scope? If so, the Sun will be the same size.

[ianpwilliams]

Oh yeah, of course it will! I often find it's easy to miss the obvious when it comes to astronomy.

Can anyone help with my other questions?

[ArmyAirForce]

...........so that I could get a full sun with the moon nearby, then partial eclipses, then the moon at the other side..........

It's a new Moon, I doubt you'll see anything until it touches the Solar disc.

 

.....The guy on the tutorial link says to go for 1/2500 to 1/400, but I guess that would be for a fully exposed sun, with longer exposures required the more the sun is covered?

No idea, I've never shot an eclipse through a scope before. I'd suggest shooting in RAW, at a number of different exposures during the eclipse, and edge on under exposing rather than over exposing.

 

...."When you are happy take between 40 and 100 frames.......the idea is to have a final stack of around 60 frames)". I take it this is not necessary? Or do you indeed take lots of shots and stack them?

I'll probably shoot the full clear disc with two to three hundred shots before the eclipse starts. I can then shoot the Moon as it crosses the Sun, and overlay the Moon onto the detailed solar stack so I can have the shadow along with plenty of solar surface detail. 

 

He also talks about taking Flats - is that worth doing?

I've never done flats for solar images.

 

Also, when you talk about Solar Tracking mode, how does that differ from the normal tracking mode (whatever that is, I'm guessing the normal mode is Siderail?)? I'm not actually sure what tracking mode my mount is in (I bought it second-hand).

Synscan defaults to Sidereal on power up. You need to go into set up, tracking and select solar, as the tracking speed is slightly different to stars.

[OutThereSomewhere]

The alignment device only ships to the US and Canada according to their website, which is a pity as it is a good idea.

[Carina Lass]

How big? Same size as the moon.

Approx 1/2 degree wide

[ianpwilliams]

Thanks, looks like I'm fully prepared. Just need to do a dry run now.

[ianpwilliams]

Didn't realise this eclipse will going on for over 2 hours! Don't need to worry about missing it then.

[ianpwilliams]

Does anyone know if the sun is an option in the GOTO menu? I can't find it anywhere, although I wouldn't be surprised if it wasn't there, because I'm guessing the manufactureres wouldn't want people accidentally slewing to the sun and damaging their telescopes and/or blinding themselves.

[ArmyAirForce]

It's not, for safety reasons.

[ArmyAirForce]

Just set the tracking to Solar, unlock the clutches, and swing the scope roughly in the direction of the Sun, relock the clutches, and then slew the scope until the tube shadow on the ground is as small as it will go; then you are pointing at the Sun.