Antlia 3nm Pro narrowband filters

[Backyard Space Dude]

I recently purchased a set of SHO Antlia 3nm 1.25’ filters. Up until now, I’ve been using 7nm ZWO filters. Not having sold my ZWO filters yet, I thought it would be a good opportunity to compare the two. This will hopefully give prospective buyers a good idea of what to expect. Hopefully this is in the correct area of the forum!

Like a lot of people, I simply can’t easily afford a set of 3nm Chroma or Astrodon filters, so having a set of 3nm filters at roughly half the price, with technical specifications that match the top-end brands is very enticing (I'm talking OD5).

The data was all taken on the night of the 30th January, 2021 from my back garden. There was a 98% illuminated moon. Bortle class 4/5 with an estimated sky quality of 20.61. This data is according to the Clear Outside weather app, as I have no way of accurately recording this myself.

Images shown here are in the format of .gif to better show the direct comparison, as I have found side by side images are difficult to differentiate. Each .gif scrolls through the 7nm image, then the 3nm image in 2 second intervals. I perhaps should have gathered more data on the Oiii filter, but that's hindsight now!

I have also made an unboxing video, which you can watch here. (I'm new to video creating, and it also encompasses some beginner knowledge on narrowband filters, so you can skip through that bit!)

I have supplied the original data with calibration frames available for download here. Let me know if you find anything interesting!

Equipment
Telescope - Skywatcher Esprit 100 & matching field flattener,
Filter wheel - ZWO 1.25” EFW,
Camera - ZWO ASI1600MM-P (Gain 139, -20C)
Mount - Skywatcher NEQ6-P,
Guiding - ZWO ASI174MM & Skywatcher finder scope,
Acquisition - ASIAir Pro & iPad Pro,
Calibration with Bias, Darks and Flats and registration performed in SiriL.

All images had an auto-stretch applied in SiriL, exported as a 16-bit tiff and then converted to a .gif and resized in Photoshop. For an uncompressed true representation, feel free to download the original data from the link above.

NGC 7822 - Ha - 1x600s

 

NGC 1499 - Ha - 1x300s

 

M 42 - Ha - 1x180s

 

IC 2177 - Ha - 1x300s

 

IC 1805 - Ha - 1x300s

 

IC 1848 - Ha - 1x600s

 

IC 410 - Ha - 1x180s

 

B 33 - Ha - 1x300s

 

B 33 - Oiii - 1x300s

 

B 33 - Oiii - 1x30s

 

Having never been exposed to 3nm filters before, I am probably not in the best place to make conclusions. I was initially taken back by the Oiii results, but I gather this is troublesome for most filters, and I would expect some negatives having paid half the price of brands like Astrodon and Chroma - perhaps someone would be able to provide some insight into this? However, I can't deny that I am very happy with the results and I'm looking forward to getting stuck into a new target ...as soon as the clouds clear!

[tooth_dr]

Nicely presented. Some significant differences there. 

[Davey-T]

Thanks for taking the trouble to do this, just got 3nm Ha Antlia filter but haven't had any weather to use it yet, will post some results when I do.

Dave

[JamesF]

I wonder if the effects in the OIII images are reflections off the camera window or sensor?

James

[Laurin Dave]

Interesting comparison and quite a difference ..  I’d guess that the big halos in the Oiii are reflections off the filters with the smaller artefacts being caused by  microlens/sensor window reflections 

[Backyard Space Dude]

Thank you all for your comments! Yes, I'm lead to believe the smaller artefacts around Alnitak are microlens issues with the ASI1600MM-P.

[Sp@ce_d]

Good timing, I’ve been mulling these over in light of the extortionate price increases with the astrodons & chromers. Bit the bullet & ordered the 36mm Ha & SII over the weekend. Waiting to hear when the OIII will be in stock. Will be interesting to compare with my 5nm Ha/SII astrodons anyway. The OIII is the one to get right. My astrodon OIII is 3nm. Your results clearly show improvement on a difficult target.. micro lensing aside. Considering the astrodon is well over twice.. two and a half even.. the price, these could be very popular if they can maintain QC & make them quick enough 😏

Thanks for doing this.. very helpful 

[Backyard Space Dude]

My pleasure! Glad to have helped.

[Stardust]

OOh these are nice, just trying to see if I'd benefit changing my HA 7nm Baader for one of these. Thanks for doing the comparison

 

[Backyard Space Dude]

9 hours ago, Stardust said:

OOh these are nice, just trying to see if I'd benefit changing my HA 7nm Baader for one of these. Thanks for doing the comparison

 

Not a problem at all, thanks for the comment! Here's a comparison on Cloudy Nights between Baader 7nm and Antlia 3nm:

https://www.cloudynights.com/topic/749764-comparison-antlia-3nm-ha-filter-to-baader-7nm-ha-filter/?hl=%2Bantlia+%2B3nm#entry10839989