Solar Filtering Advice.

[Mr TamiyaCowboy]

hello everyone.

after purchasing some Baader film with the advice from forum members, i have now made a homebrew solar filter or two. i am in the middle of fabricating a solar filter for my 114mm telescope

i first made a filter for my smaller heritage 76mm Skywatcher. it has a short 300mm focal but a fast aperture at around f3.9. after checking filter by holding up to the sky everything is well.

first view was amazing, i had seen so many white light images from other forum members post that took my breath away. but my views are a let down.

Full disc i have, i have sunspots but i also have weird artifacts (visual). there is a blue'ish purple band around the disc. when i move the scope slightly left or right, this blue'ish halo band moves. move scope left the halo appears on the left of the suns rim. move the scope slightly right the band moves to the right side of the suns rim, same if i move the scope up or down.

this is just the first problem. the second is even more annoying. remember as a kid watching heat rise of the road surface in heat waves. well i have the same waves when i am looking at the sun, through my eyepiece's. focusing is a pain in the rear a tiny touch and sunspots disappear.

i would just like to have a nice view and something that will give me good imaging. why am i seeing this funny haze halo, and how can i stop sunspots disappearing, but also remove this heat wave viewing problem to.

can i use a moon filter (ND) to help or will i need other filters to give the best views from the small reach scope.

is it possible you leet solar imaging wizards can let me glean some well needed knowledge and have me imaging decent pictures, but also have decent viewing.

thank you

Tami

[E621Keith]

The purple halo band sounds like chromatic aberration. What eyepiece were you using?

Thermal current is unavoidable, but you can reduce it by choosing your observing surface carefully. Don't go near black tarmac.

[iwatkins]

... or concrete.

And try to avoid looking at the sun over concrete, tarmac, houses that are nearby etc.

I find it best to view over grass if at all possible. Seems to cut down on visible ground currents.

Cheers

Ian

[todd8137]

hi there well i do not have the said film,but the thousand oaks rg4 stuff i made a 12x10 circle on for the 300p,i also made a cd size one for the 300p,i have 2 others a full ap for the sct 9.25 and 4 inch one for the 9.25.

i shoot over concrete never been a prob lets rember we are shooting in day light and heat is every where

well i find on the 300p that green filters and blue help with contrast, both masks give the same view the full mask for the 300p some times as a prob with contrast full stop

the sct 9.25 is great with both webcams dslrs no probs,

if you do make a full size one you could also cut a smaller hole in some card the same aperture as the mask ,so you can stick over the top if you wish,some time with the scopes cutting down the size really helps loads try some filters just turn the color of or post process back to white

Pat

ps you could always use a fan a old pc one hooked up to some old car battery or some form of 12/13 v will cool the inside and mirror of your scopes just switch it of when you image,back on when you not

[Mr TamiyaCowboy]

i only have the eyepieces that come with the scopes from factory and a 2x barlow that came with the 1141.

25mm : gives a decent disc and sunspots, but very small image.

10mm: gives better image but blue'ish purp halo'ing. sunspots harder to spot.

12.5mm ( 25mm @2x barlow ) better image than 25mm but nearly same image as 10mm none barlow'd

5mm ( 10mm @ 2x barlow'd) massive haloing, sunspots very poor. disc is more a white sheet of paper. no contrast and/or resolution.

[E621Keith]

If the 10mm is a modified achromat, then that'd be the source of the chromatic aberration. I suggest buying another eyepiece.