12" White light Newtonian

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
Post Reply
AndiesHandyHandies
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1444
Joined: Fri Mar 30, 2018 6:46 am
Location: Derbyshire UK
Has thanked: 3292 times
Been thanked: 1887 times

12" White light Newtonian

Post by AndiesHandyHandies »

Hi

I now can use some bits for a 12" dobsonian.
I lent the mirror to someone and they cleaned it without asking and took half the aluminium off!
'Home' aluminised at my first club and some pre-cleaning artefact in the coating it looked like.

So might as well take it all off.

Whats the best narrow band filter (s) to use?

Rod points out he used a 10" Newtonian for solar projection for hours with no issues.

Andrew


User avatar
MalVeauX
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1858
Joined: Tue May 09, 2017 7:58 pm
Location: Florida
Has thanked: 1171 times
Been thanked: 1360 times

Re: 12" White light Newtonian

Post by MalVeauX »

Heya,

Well, use a 656nm (Astronomik HA 12nm) filter for poor seeing.
Use a 395nm or 430nm (Andover or Edmund Optics) for higher angular resolution with very good seeing.

Very best,


AndiesHandyHandies
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1444
Joined: Fri Mar 30, 2018 6:46 am
Location: Derbyshire UK
Has thanked: 3292 times
Been thanked: 1887 times

Re: 12" White light Newtonian

Post by AndiesHandyHandies »

Thanks.


bart1805
Almost There...
Almost There...
Posts: 636
Joined: Mon Feb 06, 2017 9:04 pm
Location: The Netherlands
Been thanked: 1 time

Re: 12" White light Newtonian

Post by bart1805 »

Don't forget to de-aluminise the secondary mirror!


User avatar
marktownley
Librarian
Librarian
Posts: 42269
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20424 times
Been thanked: 10242 times
Contact:

Re: 12" White light Newtonian

Post by marktownley »

bart1805 wrote: Sat Oct 26, 2019 8:20 am Don't forget to de-aluminise the secondary mirror!
Depends how much light you want coming through 😉


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
bart1805
Almost There...
Almost There...
Posts: 636
Joined: Mon Feb 06, 2017 9:04 pm
Location: The Netherlands
Been thanked: 1 time

Re: 12" White light Newtonian

Post by bart1805 »

marktownley wrote: Sat Oct 26, 2019 10:58 am
bart1805 wrote: Sat Oct 26, 2019 8:20 am Don't forget to de-aluminise the secondary mirror!
Depends how much light you want coming through 😉
Yep, you are absolutely right!


allhoest
Almost There...
Almost There...
Posts: 521
Joined: Sun Mar 22, 2015 7:48 pm
Has thanked: 714 times
Been thanked: 496 times

Re: 12" White light Newtonian

Post by allhoest »

"Don't forget to de-aluminise the secondary mirror!"

If you do so, you will have a very strong filtering.
Maybe you want it that way, but keep in mind that you will have to collimate it!


christian viladrich
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2150
Joined: Sun Jun 14, 2015 4:46 pm
Location: France
Has thanked: 1 time
Been thanked: 2712 times
Contact:

Re: 12" White light Newtonian

Post by christian viladrich »

As said by Alexandre, just keep the primary uncoated and the secondary coated.
Regarding filters, it all depends on the seeing conditions at your place. A 300 mm is a bit of a large telescope for solar image.
The range of usual filters are :
- deep-sky Ha, when seeing is bad,
- 540 nm, when seeing is good,
- deep-sky OIII, when seeing is pretty good,
- 430 nm, when seeing is excellent,
- 396 nm, when seeing is perfect.


Christian Viladrich
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
Post Reply