Questions on solar white light

[david_taurus83]

I've only tried this once in the past and enjoyed it but I didn't keep up with it as it meant changing out all my deep sky image train to fit a Lunt wedge. Seeing all the great WL images now the sun is becoming active again so I fancy giving it a go again. My question is can I simply put a solar film filter up front of my Esprit 100 during the day and image in WL with my deep sky imaging kit? Ie is it safe to use with my filterwheel etc. Do I need the Baader photo film or will the normal stuff be OK? Would be using my ASI533MM.

[knobby]

Not overly qualified to answer but I've used my 72ed with a flattener and filter wheel (settled on the Ha filter as it seemed appropriate) and a DIY baader film front cap filter.

Did this a few weeks ago ... Very small but satisfying. ☺️

Just be careful to make sure the filter can't fall or blow off !

[Elp]

There is a slightly less nd version of the Baader for photographic use, but for safety's sake it might be best to get the visual one and use that. I've got that and the Seymour one which gives a yellow tint to the view.

Make sure the film is cut larger than the front objective and make a cell around it which connects to a tube which is snug around the dew shield. I made mine out of thick cardboard for rigidity and glued it with gorilla glue and left it overnight with a weight on top to set to the front cell.

You don't really need the filter wheel as your camera is mono, I sometimes use a UV/IR cut filter on the front of the camera, doesn't really make much difference, for viewing I use one just for added safety.

[david_taurus83]

Thanks for clarifying. I also would prob use the Ha filter in the filterwheel as it seems most appropriate. I'm guessing I would be better off making the aperture 55mm so imaging at F10?

[Elp]

Not sure if the ha filter will benefit, I think it will end up cutting most signal so you won't see anything, no harm in trying. White light is quite contrasty anyway, there's no harm in stopping down to increase image contrast, here's my last attempt at 60mm/360mm f5.9, some people use a baader continuum for further contrast visually, I sometimes use a green numbered filter instead:

[Freddie]

You would be better off using your green filter.

[Pete Presland]

+1  for using the green filter as well, it comes fairly close to a Continuum filter

[Steve Ward]

An Oiii or a UHC will work as a contrast boosting filter for WL imaging to save you forking out for a Continuum  , you probably have one or other in your DS arsenal ... 

You'll want the ND3.8 Baader film to accompny it though rather than the ND5.0.

I personally use the ND3.8 + Oiii combo.

[david_taurus83]

The Baader 5.0 film came today. Should have enough spare to knock something up for my 150 heritage dob and maybe the binos. That's why I didn't order the 3.8. 

[david_taurus83]

Should I also stop down to f10? Any benefit leaving things at native f5.5? 

[Nik271]

If you have th ND5 filter that cuts out a lot of light already, so F10 plus ND5 plus  another filter may be too dark for the camera. Also at 50mm aperture the resolution of the scope is considerably diminished, the surface granulation will not be easily seen (the granules are about 2 or less arcseconds). 

I would try it first with full aperture with the Baader ND5 and a green filter.

Edited July 13, 2022 by Nik271

[david_taurus83]

Thanks for all the suggestions. I made my solar cap over the last couple of evenings. Made it out of a 6" plastic drain pipe cap. Cut a 100mm hole out of the middle and inserted the filter cell on the inside. With some strips of soft velcro it is a perfect snug fit. I added some safety cord as a precaution as well. Had a quick go earlier. I'm glad I got the 5.0 film as I have to set gain to 0 and only 3.5 millisecond exposures. Anyway, here's my first picture captured with the Oiii filter. It seemed a bit steadier than the green today. Stacked 20% of 700 frames or so in Autostakkert3. Pseudo colour version out of mono. Not sure if it's just seeing or focus but I'm pleased with the result. Will experiment more with AS3 in future.