Skywatcher OIII and UHC

[argonaut]

Just wondered if anyone had used these new filters from Skywatcher. Not sure if I've missed a review or not.

Thanks.

Glen.

[Andrew*]

I haven't tried the OIII, but teh UHC is excellent. I couldn't tell the difference in any respect between that and the Orion Ultrablock. Before you ask, they are not rebadges of the same filter - just very similar in use.

Strangely, the S@N reviewer, if he can be trusted, reckoned the Orion was better, but to my eyes there was no reason to take the Orion over the SW.

HTH

Andrew

[John]

I reckon the UHC is the same as a Telescope Services UHC filter that I tried recently - the pass graphs look the same (don't know how accurate they are though ???) and the printing on the side was virtually identical. I've got an Orion Ultrablock now but TBH I can't tell the difference in effect between it and the TS UHC which mirrors Andrews experience with the Skywatcher UHC.

John

[ngc2403]

how do people review filters?

the uni has a nice USB plug and play spectrometer and it is perfect for measuing the band pass of filters. why does nobody else do this??

why trust the makes graph?

[Ben Ritchie]

People do do that

http://www.astroamateur.de/filter/oiii.html

but I haven't seen a plot for the Skywatcher OIII, which i'm very interested in too. My main concern is that it's like the Baader OIII which is apparently a rather narrow filter (visible in the link above) and cuts rather too much into the 4959 angstrom OIII line.

[Doc]

I'm realy interested in this thread as these are going to be my next purchase.

But is the Skywatcher 0111 and UHC going to be any good in a 16" Dob at F4.5?

Or should I go for a different one.

[Andrew*]

I'm realy interested in this thread as these are going to be my next purchase.

But is the Skywatcher 0111 and UHC going to be any good in a 16" Dob at F4.5?

Or should I go for a different one.

Doc,

both will be very worthwhile in the 16" IMHO.

Andrew

[Doc]

Thanks Andrew..

Just to clarify a UHC blocks out light from streetlamps.

[ngc2403]

thanks for the link,

not seen that before. though why don't S@N or other mags do that sort of thing???

some of those filter curves look terrible!

PS looks like the same spectrometer as the uni has too

[Ben Ritchie]

Whoops, didn't quite give the link I intended! That one's OIII only, there's many more at the parent page

http://www.astroamateur.de/filter/

some of the leakage is quite interesting for the CCD narrowband filters, e.g. the significant blue transmission in the Astronomik H-alpha filter that I have...

[ngc2403]

i got that thanks

like you said some of the lumincon and Astronomik filters are leaking light at UV and IR!!!!!! not very good if you are trying to image.

i see that he has also done the custom scienitific filters too. they look very nice if just a little lower in max transmission but then better SNR

[Andrew*]

Thanks Andrew..

Just to clarify a UHC blocks out light from streetlamps.

Yes and no. A UHC isolates (only lets through) light from the OIII and Hb wavelengths (some pass Ha too, although this is only of benefit for imaging). It blocks all else, including street lights.

Obviously this makes it only useful for targets that emit particularly strongly in these wavelengths, namely emission nebulae, planetary nebulae and supernova remnants. Reflection nebulae (M45 nebulosity, M78 etc.), Galaxies and stars are all dimmed by use of any filter.

The Veil nebulae and an OIII filter is a perfect combination - you will be amazed how it jumps out at you once you've been trying to look for it for hours without a filter.

UHC passes more light than an OIII filter, the latter being dimmer and a bit mroe picky on targets, but generally more effective on the right ones.

HTH

Andrew

[Doc]

Once again Andrew mmany thanks.

You have a knack off explaining things very well.

[John]

There was a very good review of filters by David Knisely on Cloudynights a while back. It did not cover the latest filters of course but the overall recommendation seemed quite sound to me - if you can only afford one filter go for a Narrowband UHC / Ultrablock, if you can afford two then get an OIII as well.

Here is a link to that review: Filter Performance Comparisons - Article

John

[Andrew*]

Once again Andrew mmany thanks.

You have a knack off explaining things very well.

Why, thank you - happy to be of assistance.

Andrew

[gliderpilot]

I have the Skywatcher OIII filter and have found it very effective - emission nebular such as the Orion Nebula and planetaries are stunning. It offers a considerable jump in contrast and detail but as to its technical performance I can't comment - other than it does work!

Mark

[argonaut]

Thanks for all the posts everyone. It's been very interesting indeed.

I am still in the decision stage :-)

Glen.