Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 16, 2014 16:17:26 GMT
Are Hydrogen Alpha filters useful for viewing nebulae and such? drdavesouthafrica on NSN has broadcast some nicely detailed views of some nebulae, but they seem to be in black and white. What could I expect if I were to screw one of these filters on my SBC2000? Would it cause me to use longer integration times? Would you all consider one of these filters worth the expense?
Thanks, Kim
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 16, 2014 17:06:05 GMT
A HA filter allows you to make longer exposures to bring out those faint emission nebula details without overexposing the sky. It will appear as black and white. It is unsuitable for planets, galaxies, etc.
You will need to make sure the stock IR cut filter is removed from the Sammy, or you will see nothing with this filter attached. The stock IR cut filter on the Samsung blocks HA.
To be honest I'm not sure 8.5 sec is enough to use a HA filter, all visible light will be blocked.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 16, 2014 17:20:47 GMT
Actually HA is at the edge of the visible range, it is very difficult for human eyes to see. This is why it takes a MASSIVE scope to see color in this range. But I think I was wrong, an HA filter image will be RED, way too red, so I think people turn off the color to make it more pleasing to look at.
(I have never used one, so how its actually seen by a color ccd is a guess)
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 16, 2014 17:43:57 GMT
Thanks hemmi. I knew there must be a reason that I haven't seen more HA images on the various astro/video forums. I have removed the IR filter from my Sammy, but longer integration times are not an option for me due to the limitations of my camera and the fact that my 6SE only operates in Alt/Az.
Kim
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 16, 2014 19:44:44 GMT
Hi Kim heres a comparison thread I did with a UHC filter (for nebulas) and a raw without both same integration and within minutes. The UHC works and brings out more detail but filters the light green through the Sammy. As Hemmi says nebula only they dont work for galaxies. astrovideoforum.proboards.com/thread/59/optics-uhc-filter
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 16, 2014 19:59:39 GMT
Hi Kim heres a comparison thread I did with a UHC filter (for nebulas) and a raw without both same integration and within minutes. The UHC works and brings out more detail but filters the light green through the Sammy. As Hemmi says nebula only they dont work for galaxies. astrovideoforum.proboards.com/thread/59/optics-uhc-filterThanks Carl. I guess you could deal with the greening of the image with the UHC by adjusting the white balance settings in the Sammy. The UHC looks like a worthwhile tool to have in the arsenal.
Kim
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 12, 2014 18:29:09 GMT
Any word on this Hemmi? You mentioned you bought one. Im keen to find out if it kills all colour or not.
This would work well under my brutal light pollution. Would allow me to expose longer and use higher gain setting im guessing. But if it kills all colour im no so interested.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 12, 2014 18:39:55 GMT
From what I've heard and read Ha filters need longer exposures and the use of a Monochrome CCD. Color cameras can work, but on as good with Ha filter. I suggest UHC filter or a sky glow filter. I don't use any filters with my scb 2000.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 13, 2014 2:11:05 GMT
Yes I have the HA filter, however no camera at the moment. You need very good tracking with a gem mount to use a HA filter. And most likely guiding.
I will report as soon as i get my cam back
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 24, 2014 3:24:00 GMT
Yes I have the HA filter, however no camera at the moment. You need very good tracking with a gem mount to use a HA filter. And most likely guiding. I will report as soon as i get my cam back Many are very confused as to when to use a good quality 6 or 7 nm Ha filter. I mainly use my Orion 7 nm Ha filter when there is a full moon up high and there are plentiful emission nebula objects, so forget spring time during the galaxy season for us Northerners. Also everyone wants to see colour and I understand that but using the saturation esp. at higher amount will rob the contrast and detail that this filter is very known to provide. Since we are only detecting one lightwave (red) and not OIII (green) or Hb (blue) we really will not pickup the true colour of the emission nebula and some planetary nebula like M27, Helix or M57. ** It is always best to use this filter for BEST contrast and detail with no saturation therefore black & white. If you really need to have a bit of false color then use the saturation at a low level. Also since the filter is very narrow expect to use longer exposures which means at minimal your mount better track really well. Kim sorry to say but 8.5 seconds will be useless when using a Ha filter.
Chris A Astrogate
|
|