If you could only have a variable polarizer and 2 filters...

[John]

An O-III filter can make the difference between seeing something nice and seeing virtually nothing at all on some objects such as the Veil and Owl nebulae. I have an O-III (Lumicon) a UHC (DGM NBP) and also an H-Beta (Astronomik) but the O-III gets much more used than the others because of the impact it has. The H-Beta is very rarely used, so far.

The difference illustrated below is more or less what I experience when I use the O-III filter with my 12" dob:

 

[JOC]

Hi John, that is a target I am still unsuccessful with.  I know it goes on for some distance - however, those shots above - if I want a named/numbered location to send the Goto to in order to get that portion of it what would I need to enter and what sort of magnification to get it to fill the EP like those photos - if I have a def. destination and magnification it should enable me to try my cheap O-III and see if I get a similar effect as, so far, I am seeing nothing.  I know you have a considerable amount more mirror than I do, but I get the impression that it is still a 8" Dob object and it would be good for this thread to compare the cheaper end of the O-III filters with those photos.

[John]

The object shown is the Eastern Veil Nebula (NGC 6882 in the main although some parts of it have other designations). I get a similar amount in the field of view when I use my 21mm Ethos in my 12" F/5.3 dob so that is 76x and a true field of 1.3 degrees. This is the brightest segment of the Veil.

The Western Veil Nebula (NGC 6960) AKA the Witches Broom, runs right past the star 52 Cygni and is around the same overall length as the Eastern part but a different shape. These 2 segments are around 3 degrees apart (6 moon diameters). These sketches of the Eastern and Western sections were made with an 8" scope at 40x under a desert sky. My 12" does a touch better on a really dark night from my back yard

 

 

 

[JOC]

40 times, gets you that much of it - wow, that means my 32mm omni plossl  is probably the weapon of choice - I might have been missing it due to being too close - I think I probably scanned with closer than that.  I'll add those NGC numbers to my book - the goto holds the NGC table so I should be able to dial for them when it is working and then I'll try the cheap filter next time I'm out and report back to the thread.

[Luna-tic]

19 hours ago, LukeSkywatcher said:

A variable polarizing filter isnt really needed for either Solar or Lunar observing. If you want a polarizing filter for Lunar observing, a plain old Moon filter is a LOT cheaper than a variable Polarizing filter. 

Orion's rotating dual polarizer is about $40, lots cheaper than many light filters. A regular polarizer or Moon filter only cuts a set amount of light, what I like about the dual polarizer is that you can dial in (or out) the brightness you want, depending in some part on the phase of the Moon you're observing

8 hours ago, JOC said:

The polariser - I read a lot that people find the moon too bright, as you wrote, I don't have a real problem with it either.  However, when used the tuning of the 2-plane polariser does offer some flexibility to tone things done brightness wise.  I don't bother on the moon, but it is interesting to experiment with it on something like Jupiter.  A couple of good tips for it is to split it in half and either put one bit on the bottom of the EP and rest the other on the top of the EP if the eye relief allows then you can move is around easily.  Or put one bit on the bottom of a Barlow and the other on your EP so you can easily spin the EP to get the changes.

The Light pollution - haven't tried it yet, but don't know why - I do have poor light polluted directions and maybe I should see if it makes a difference

The UHC and O-III - I took the UHC out last night - I don't think it improved the dumbbell nebula, or the ring nebula for me, Even with the UHC on I couldn't find the catseye or the Veil.  However, I think the 0-III is supposed to be better for the veil, though I have tried it in the past and still not enjoyed success (it is entirely possible I haven't been looking in he right place though!!).  At the moment I am still experimenting, but so far I haven't gone 'wow' with what I've tried, and if I am being honest the ring and the dumbbell were better for me with the naked eye.  However, there are loads of objects left to find and maybe they will become useful soon and I will continue to try with them

I received my O III and narrowband UHC/LPR filters, along with my polarizer the other day. LP is prevalent in my local area, we're in the midst of three towns about 10 miles apart, so there is glowing horizon all around. I used the UHC on the Ring Nebula the other night and it made it much better to look at, the hole in the middle was much more distinct and even a bit of color came through. The viewing overall was fair to marginal that night, as there was a high veil  of thin cloud from an incoming front. Haven't tried the O III yet, and the polarizer will get a try in the next week, as the Moon waxes toward 1st Qtr. and then full. Rain for the next couple of days.

I like the idea of placing halves of the polarizer on separate lenses and then just rotating the EP, have to try that. At the observatory, using the club's polarizer, I'd hold the EP just out of the diagonal, rotate the polarizer to block the desired amount of light, then insert the EP and focus. Your method would be much easier.

 

[JOC]

48 minutes ago, Luna-tic said:

I like the idea of placing halves of the polarizer on separate lenses and then just rotating the EP, have to try that. At the observatory, using the club's polarizer, I'd hold the EP just out of the diagonal, rotate the polarizer to block the desired amount of light, then insert the EP and focus. Your method would be much easier.

I am afraid I can't claim the knowledge of those - I got those tips from YouTube videos, however, I have tried both methods and they both work, but obviously chucking it on top of the EP very much depends on the angle of the EP in the unit - putting different halves screwed into two different places is far safer.

[RT65CB-SWL]

I have this 1.25" variable polarizing filter...

My other two, sorry five, are Baader neodymium & Baader contrast, plus a No#47/violet, a Star Analyser 100 and a LPR/IR cut-off on my web-cam... (damn! that is three to many).

Seriously though, (excluding the polarizer), the other two filters of choice if I was buying from the start it would be the Baader neodymium and Star Analyser 100. note: all are 1.25".

[Piero]

Oh-okay...here are my filters...   

- 2" Lumicon OIII (old model), 2" and 1.25" DGM NPB (1.25", TV60).

- 1.25" Lunt (TV60) and 2" Baader Herschel wedges

- 2" Baader polarising filter which is used on solar observing at middle power because to my eye the Sun is too bright and I found this often causes me headaches. I have a 1.25" polarising filter used with the 1.25" Lunt HW for the same reason. I also like the polarising filter when observing Jupiter or Venus time to time. Not required, but I often enjoy it.

- 1.25" Solar continuum filter used with the 1.25" Lunt HW. The 2" Baader HW comes with a 2" solar continuum filter inside.

I would not give up any of these filters. 

 

In Italy I also have 3 1.25" Orion colour filters which were bought upon advise of a seller back in '97. Apart from the green filter which was used before I bought the 1.25" solar continuum filter, these filters haven't been used much, if not any.. 

[AstroKerr]

You guys are great! 

Grabbed a couple mainland china lunars, ND 13% transmission and they seem to be a-ok - under $7 and free shipping.

Still scouting for a nice OIII, John, in the auctions - but just from your images - wow, what an improvement - found an older Meade DSI and DSI Pro II for a few farthings, and they give images very like your unfiltered veil - was wondering how to clean things up on the optical side vs post proc - now I know.

Phil, JOC, Pieroa et al - I am taking note of your referrals and advice to be sure - side hunts are on - you guys are all very helpful to everyone who reads those posts. 

[John]

Improving images is different from improving the visual experience although I believe that filters can help with imaging as well. I don't image though so I can't advise on that. For what it's worth my current filters are:

- 2" Lumicon O-III

- 2" Omega DGM NBP (UHC type)

- 1.25" Astronomik H-Beta

- 1.25" stock lunar filter (used for outreach if people complain about the brightness )

- 1.25" Lunt Hershel Wedge with integral ND filter and single polarising filter on eyepiece.