Aligning a Solar Telescope

[leebca]

Not sure if there is a better place to post this inquiry or not, since the observing forum is for 'night' observations.

I have volunteered in my USA astronomy club to help them on outreach projects (they go to places that invite them and setup scopes and let the public know about amateur astronomy and the club).  Not sure if clubs do this in the UK or not.  Anyway. . .

They asked me to setup and monitor people looking through the: 

Coronado SolarMax II 60 Double Stack Solar Telescope with RichView Tuning with 10mm blocking filter

They didn't ask me if I knew what I was doing, and I didn't claim I knew anything.  I just said, "Yes."     I figured I didn't need to look anymore dumb in their eyes then I already did!     So there will be issues of fine tuning for the public (mass) viewing, but the first step will be to align it.  It is on an EQ mechanical mount.  I'm just getting the hang of aligning GoTo scopes at night and marginally succeeding at that.

How do you align such a scope during the day -- no stars (but one) visible?  I can't keep adjusting it between people looking through it.  Sometimes there's a line of 10+ people waiting to look through their scopes.  So, it must track the sun as best as I can get it to do so.

So I did what most would do in such a situation -- I searched the Internet.  I found a YouTube video by Nick (in the UK), but I either need more 'hand-holding' through the alignment process or I was confused by his accent.     <Just kidding>

Maybe someone on the forum knows this scope and, on an EQ mount, can tell me in detail, how to align it.  I would appreciate help.  

LEE

[Mark at Beaufort]

Lee do you know whether this scope is fitted with the Coronado standard sol ranger finder?  Here is a link to an American website to show you what it looks like and an explanation of how it works - http://www.optcorp.com/coronado-solranger-solar-finderscope-h-alpha-telescopes-sol.html

Mark

[leebca]

Thanks Mark.

I don't think I will have a problem finding the sun.  There is a finder scope on the telescope with a pinhole feature.  Or are you suggesting that once I have the sun in the field of view, it will stay there with no further adjustment?

The challenge I think I have is aligning the scope so the EQ mount will take over and keep the sun in the field of view.

[ronin]

Set the latitude and whatever else is necessary and simply point the thing as accurately North as you can.

Then locate the sun (with complete safely) and allow the mount to track.

It is visual use and although the set up is approximate it should be adaquate for solar tracking.

Every so often check the position of the sun in the scope and make minor adjustments. That will make think even more that you have some idea what you are doing. Well it works for me on occasions. :grin:

You will have to check the suns position in the eyepiece anyway as even if it turned out perfectly set up someone will manage to nudge it a bit.

[NGC 1502]

Hi Lee, good points already given.  Does the EQ mount have a motor drive ? If it does, once you have the sun visible in the eyepiece, the mount will track it. If it's a manual drive, put the sun to one side of the field of view before each new 'customer', and let it drift across to the other side. Realign for each person.  You can use the drift to explain that it's caused by the Earth's rotation.

When setting up an EQ mount for visual use, highly accurate alignment to the pole is not needed, near enough works ok.

Don't be afraid to ask your club for help. If it's a clear day things can get busy, you will need helpers to take over to give you a break.

And yes, lots of clubs here in the UK do 'outreach' astronomy, by day and night.

It helps if you have basic info about the sun, nothing fancy is usually needed, distance, diameter, age, temperature, composition would get you by, unless some smart alec turns up 

Good luck with what you are doing, Ed.

[ollypenrice]

Ronin's right. Use a compass (held away from the fairly magnetic mount) to find North and the Lat scale set to your lat and that should do quite well. It will need checking regularly but should meet your needs. Use a low mag EP for greater tolerance.

Olly

[leebca]

Thanks all.

Ed et al, it has the Advanced VX mount.  It's motorized.  It's a relief to know that the alignment isn't that critical for this.  My iPad has a compass app that will be good for this.   I'll have to become familiar with Sol and star-life for the upcoming event.

Good to know that these programs are done in other countries, too!

LEE

[Luke]

Like the others, I point the mount north and that's pretty good.

Also, I set the tracking rate to Solar. I don't have a VX mount, but I believe you can also change the tracking rate to solar for that one.

Best of luck with the outreach. Hope everyone has an amazing time!

[jezhughes]

Can you get to the site in the evening the day before or something? If you can, maybe set up and align, then mark the ground where the feet are. I'd just use some spray paint or something that's not going to do permanent damage, or take a golf ball and hammer it in the ground to make an indent if spray painting the ground is a bit naughty

Then when you go back (assuming you haven't changed your mount adjustments in the mean time), you can just pop the legs on the paint marks / in the ball divots and you'll be pretty well aligned!

Or.... Just use a compass. But personally i find it a bit of the nightmare considering the mounts so magnetic. You never get it exact, and it sounds like you want the mount to be accurate so you dont have to keep adjusting it during your session.

good luck!

[brantuk]

Get a guy rope and two tent pegs and, using a compass, peg out a North-South line. Set the N leg on it and the other two equidistant either side. If you do this at midday, the shadow under the line will be directly underneath since the sun is directly overhead (just to  double check).

Pop the mount on top, set it to the home position with elevation set for your observing site. Put the scope on with a sol finder, set tracking rate to solar and your ready to go find the sun.

[leebca]

Thank you all for your ideas and support.

Just as a 'dry run' I set up last Monday in a nearby vacant lot.  I had a compass but it went crazy around the mount.  Couldn't really do a good job of getting it aligned since when I got close to the scope I would lose the true direction.  Had to stand away, behind the scope and try to use a marker to align the scope to.  Then, as a safety precaution, the GoTo doesn't automatically include the Sun in the Solar Alignment option.  Had to go into the Menu and force the computer to include the Sun as an option.   All-in-all, not very good and the GoTo didn't 'goto' the sun at all.

The event was over a 2-day time, last Tuesday and Wednesday.  Things went fairly well.  There were four of us there with scopes.  I was guided by someone else's compass as to which way was north, but again, it was obviously not very accurate.  I ended up having to make an adjustment of my scope every 20 to 30 minutes in order to keep the sun in the field of view.  What took me most by surprise is having to 'flip' the scope.  I had never observed for such a long time (we were out there from 8 a.m. until 3 p.m.), so the concept of what other club members were calling flipping was new to me!

Anyway, got through it.  Got most of the kids believing I knew what I was doing!  Had an excellent view of a very large prominence, a long filament, only one or two very small sunspots, and a couple growing prominences.

For the next one I obviously need to change three things:

Get a smaller counterweight -- the one with the mount was too heavy, to balance the scope the weight had to be within 1/2 inch from the top and that interfered with the mount movement;

Get an 'in between' eyepiece -- had one too small, and one marginally too large;

Figure out how to align the scope better.

Couldn't get to the site prior to our allowed setup.  Tent/overhang was setup for us in advance.  We were on cement the whole time -- a courtyard of sorts.

That's the report!