6 replies to this topic

[svjim]

I want to image the witches head nebula. I live in a 6/7 and always use a light polution filter with my OSC ASI2600MC. The witches head nebula is pretty dim and I was wondering if using the Askar D2 filter might work better than something like the L-Pro or Antila tribune? I also have the Askar D1, but I tend to believe that the hydrogen would over power the capturing of the blue light of the reflection nebula. I don't really know, just guessing what would be best using one or more of these filters.

 

Thanks Jim

[ntph]

It's a reflection nebula--just use a uv-ir cut filter and take lots of subs. Narrowband filters of any sort are not going to help you. Best way to overcome light pollution short of moving is lots of integration time and gradient reduction. 

 

Here's my version from a couple of years ago from my B7 backyard. 130 mm f/6 refractor, QHY168c one shot colour with uv-ir cut filter--this is a two panel mosaic of only an hour or so each panel, with the "old" toolset in PI. I really should revisit this and see what the new tools can add (and my hopefully improved processing knowledge).

 

Edited by ntph, 08 December 2024 - 07:21 PM.

[John Berger]

Antlia Triband you mean?  almost said the Antlia Tribunal

 

no, do not use the Askar D2 filter for this

 

if you're planning on getting H-a from the area, then yes, the D1 is your best bet (good luck with that though, I don't think the H-a is very bright)

 

if you're planning on getting simple full color broadband images, then use a normal UV-IR cut - that might sound strange to you, but, you and other beginners must understand that light pollution filters do nothing at all to help you get better signal for -broadband- targets (galaxies, dark and reflection nebulae, I mean), it's just cutting out light from what is already present, filtering out the so-called "light pollution" wavelengths, it just doesn't do magic; those "light pollution wavelengths" include actual signal from the DSO, so that's why I say it doesn't help.

 

my logic tells me they were a lot more useful for broadband targets when we didn't have so many LED lights, because, LP filters are meant to filter out the wavelengths of those old lamps (like sodium) that used to be more prevalent; they really don't help now, except if you want better signal off of emission/planetary nebulae which are stronger in some special wavelengths that LP filters usually pass

 

my 2 cents -  just my understanding of it

 

CS,

John

Edited by John Berger, 08 December 2024 - 07:44 PM.

[Ranger Tim]

You do not need a UV/IR cut filter with the ASI2600MC Pro. There is one built-in. Shoot lots of subs. Expose so that your level of LP does not overly saturate the photo. I would recommend an exposure but I have no idea what you are shooting through. Here’s a quick and dirty Witch Head from last spring, 2600MC, Bortle 6 with No Filter. Less than 2 hours total I believe. Gradient Exterminator is your friend.

 

[John Berger]

You do not need a UV/IR cut filter with the ASI2600MC Pro. There is one built-in.

ooph, didn't know

[rj144]

I'm currently working on it in Bortle 8/9.  This is 3 hours so far:

 

 

I will add 3 to 5 more hours though.

 

Taken with a Playerone Saturn and Antlia Triband.

[AstroVagabond]

One thing I like about this hobby is that we are free to explore. If you have the budget try the various filters you mentioned and compare the results.

 

Here is my interpretation of NGC 1909 imaged using RGB filters (8h 16'), RedCat 51, and my ASI294MM camera. I collected the data under Bortle 4 skies during new moon period so light pollution was limited and moon illumination was not an issue.

 

 

~ Bill