C9.25 Imaging Train Tuning and L-Pro and Antlia Triband Filter Comparison 

Excellent presentation as always! Thanks for sharing this, very helpful; I have a similar setup and have been considering which triband filter to go with so this was very informative.

Hello, I have subscribed as I have the Antlia tri band, not used often ( Orion is perfect but not on M101) seems I was not exposing long enough so your test have confirmed I need to have longer exposures !! As it’s summer I’m after wide field so will increase the exposures! Thanks again for the video as it confirms the purchase of this filter and that I’m not using it correctly 😊👏👍

Wow very important video, just the compare I was looking for and result I expected based on my research.

The new Antlia Quad Band is out now too. I love my Tri Band but will purchase the Quad band soon

The filter precision is precisely why I shoot flats before changing to a new filter. And that leads to why I usually only shoot one filter a night - so I don't have to wake up in the middle of the night to shoot flats!

James, the sky finally cleared and I just got to try the Antlia Triband that I picked up over a month ago. I decided to try it out on the Leo Triplet to compare the result with what I got with my SvBony 80mm doublet and an L-Pro in late January. My scope likes the Triband much, much better than the L-Pro. Much tighter stars, no blue fringing at all, and it pulled out some surprising color in M66. I was also pleasantly surprised to find that the Triband setting is available in PixInsight Spectrophotometric Color Calibration.

Hi James Thanks for the great technical analysis of the aspects of your setup. I learn something from all your videos. I happen to have a similar setup. SCT9.25, Celestron OAG w ASI174 guide cam, Celestron focuser , ASI2400MC pro main camera If you replace the SCT Adapter that came with the Celesctron OAG you can use a Agena Astro - Blue Fireball SCT Female Thread to M48 (2" Filter) Male Thread Adapter part #: PAAR-BF-C-04 About $25 This will mate with the Male M48 Camera Adapter that came with the Celestron OAG to reduce the backspace distance from your focal reducer to the camera. It reduces the BF distance from the Celestron FR optical face to the face of the OAG body by 4mm. This will give you a more adjustment with the Backfocus distance to the camera. Thought you might be interested if you want to work on the BF for star roundness. Take care

Hey, sir! Just recently Sub’d to your channel, and am enjoying the videos. As one who is new to the hobby, and beginning to think more about a first filter, I found your work here to be insightful! I’ve actually been looking at these two filters, among few others (narrow band), so this gives me an initial vector. Thanks! I’m in Oklahoma, and there hasn’t been a lot of great weather lately. In my particular area, I believe we’d be considered to be “in the country”, but still Bortle 6-7 skies .. kind of just ambient street lights and the nearby city. Looking forward to getting a filter or two to help. I just thought of something, though. In my imaging train, (I have 8SE), I’m using .63x reducer, 50mm T-adapter, 16.5 and 21mm extenders, and ASI183. I’m looking to replace 21mm with filter drawer. Now, my question - could I place a 1.25” IR cut filter over my sensor, and use it in (conjunction) with another filter in the drawer, so two at once? Thoughts? Anyone else, feel free to chime in if I’m overlooking something. I have an adapter that came with the camera and allows me to place a 1.25” filter inside the front housing part of the camera. So am curious about using it alongside a second filter for light pollution/contrast. Thanks again!

I'm surprised more astrophotographers don't use, make a point of using a digital angle gauge. I use mine to level the tripod, and align the wedge to my altitude. For me an invaluable $30 investment. Glad you did this video. Very confident over a starting filter in my bortle 9 skies. You helped. Too many opinions, and choices. Can get expensive.

Excellent! Thanks.

I've been fighting a battle against terrible triangle stars in my images with a 6SE/C6 + 0.63x reducer, paired with a 2600mm pro/OAG-L/ZWO 36mm EFW. After ~2 months of some very involved tinker-testing(figuring I cant possibly make it any worse), I've finally managed to correct them to where they're almost entirely circular in the worst cases, and I might actually call the entire field "pinpoint" now compared to the original stars - or maybe saying I don't hate using it anymore is a better metric. 😆 Not sure if the following info would be helpful if you or anyone else reading ever decides to battle the triangle stars, but it certainly improved things for me. Was it worth all the effort? Probably not, but I also learned a couple things along the way, so I'm satisfied with the result of being able to actually use the C6 as a portable-ish SCT. Without any factory markings to confirm optical alignment by(besides the serial number orientation on the secondary from a photo back from when I bought it), I wasn't sure if the corrector or secondary had moved since I bought this scope 10+ years ago(this was my first scope, and I'm sure I took it apart at some point). It was always good enough for the handful of times I took it out for visual use, but was terrible for imaging and had since gone entirely unused since I purchased my GT81. From what I could tell it was performing just about as well as any other C6 photos I had seen online, but felt like I needed to at least give it a shot to see if I could make it any better. I went to the extent of manually rotating my corrector plate a full 360 degrees in 30 degree increments(marking the original position as a rotational reference point), while also counter-rotating the secondary mirror by an equal amount, recollimating at each increment, taking a test photo, and then writing my thoughts down about how the stars looked. Then I took the "best" position from my notes and used astap's aberration inspector for some further fine-tuning in roughly 5 degree steps between 15 degrees on either side of that "best" position. Rotating the corrector plate had the effect of moving the triangle 'tail' around, lengthening or shortening it, spreading it out in odd ways, all kinds of whacky things. But afterwards the triangles were almost unnoticeable unless zoomed all the way in. That difference alone allowed me to actually see the expected star-shape-backfocus-direction-pattern that I was otherwise unable to use to dial in the backfocus. The backfocus for the C6 is supposed to be 5", or 127.0mm. Prior to all of the corrector adjustments, I must have tried everything within +/-20mm from 127mm and nothing really looked great. After the corrector adjustments, I intentionally ignored setting up the exact measurement spacing and used an M42 to M48 threaded ring adapter on end of the celestron T-adapter, threaded into a 30mm m48 spacer tube on the OAG, which allowed for fully adjustable backfocus spacing. I used a resin printed stepped band-clamp to square up and lock the T-adapter tube square to the spacer tube at any point along the 30mm length, and then I brute-force tested my way down the thread length in ~1.5mm/2-turn increments, checking collimation/refocusing, and running each new image through astap aberration inspector. This ended up getting me to a final adjusted tube length of 72.5mm between the OAG and the reducer, which means I had 130.5mm of backfocus from the back of the reducer to the imaging sensor. After further trial and error after adding an electronic focuser, I found that collimating from near-focus rather than past focus improved my star shapes even more. Hindsight I should have tried this from the start to see what it would have looked like before any adjustments, but I'm 100% sure the stars are better now after seeing so many incremental improvements along the way, and I'm also much more confident in the optical alignment being 'correct', even if its only close-ish to actual perfect alignment. It puts the corner stars well within range of being correctable by blurXterminator.

Great review! Any plan for doing a comparison between the L-Pro vs Idas DTD filter? It has an infra-red band on top of triband offered by Antlia RGB. The DTD's blue band is also slightly toward the blue side of the spectrum. Thanks, appreciate it!!

Great video James, I’m curious in a comparison on a galaxy with lots of faint dust be that the black eye galaxy or the NGC3521, with dust I’m under the impression you won’t capture all the dust areas in great detail

Great video again! My dumb question, hope you answer, How do I get the telescope focal length from plate solving an image?

Great video, what flat panel are you using? I have the 9.25 with hyperstar and need to take flats. I also using the triband Antlia. Thanks

Great video. Do you use the manual rotator in NINA and slew, center, and rotate?

Hi James, I have the Antlia Triband filter as well. I recently upgraded to mono and I have seen a few folks stacking the LP filter infront of the LRGB filters to cut the light pollution. However, I have seen most of them use an Lpro. Steven Miller from Entering in to space does this for LRGB imaging in Bortle 7 skies. I am in Bortle 7 too. Do you think this 'stack' would work well with Antlia too giving me some reds while imaging galaxies?

I know how careful you've been to get the exactly correct backfocus. When you pixel poke at your image the magnificafion is really high which means the shift your seeing in backfocus is really tiny. What was the accommodation for the filter for the optical depth? Does Antila provide a value? Quick test is to do a focus and test image on a clear spot in.the focus wheel and see how much the corners shift. Not suggesting at all that anything needs doing. Certainly not. The stars look incredibly sharp. Just intellectual curiosity. You know how that goes😂😂. Cheers. Great review of that tri band filter. WOW! I'm impressed. It's doing a grear job and much much faster with a color cam. You really should remind folks just how bad the light pollution is. I have horrible LP. Can't barely make out Polaris until late at night when the city lights are at their lowest. Thanks for the info. Clear skies.

Sensei, would you happen to know if we can use the 2600 or the full frame 6200 with an OAG? Does the C4 team have the same rules asking because they have the same back focus. Thanks

I saw you taking camera angles pretty seriously. So I can give a tip that might help: In Nina in equipment session turn on the “manual rotator”. Than in frame assist or in the advanced sequencer use the option “slew, center and rotate” instead of “slew and center”. By doing that you can have a assisting window and you can manage the exact angle and the fine increments you need to have the exact angle you are planning.

It's another expense but have you considered a Starizona SCT reducer. The Starizona SCT Corrector IV - 0.63X Reducer / Coma Corrector is claimed to yield a 1525mm FL on a 9.25. I've only heard good things about Starizona's quality but haven't bought/tested anything myself. You could probably sell your stock 0.63 reducer online and recoup some of the added Starizona expense.

James , I have the same scope and mount as you. But my question is about the scope. I was shocked the first time I used the scope that I had a lot of moisture build up inside the scope . It was on the inside of the corrector plate and on the mirror. I had to take off the camera and keep the end open to get the water out. Have you had this problem ??? I am a bit upset this happens . I have my Meade LX200 for about 20 years and this never happened.

Did you measure FWHM, SNR and eccentricity of pictures in Pixinsight? This will give precise info on filters. Antila looked by miles better; but needs numbers and quantitative measurements to be sure.

Have you tried the same math with L-Extreme (which is their current model).