Moving to mono setup - Forums

After 2.5 years with my ASI294MC pro, which I am happy with, I am thinking of switching to mono. This is fate in this hobby it appears.

However, I invested quite much in this hobby over the 2 last years, having now a nice 8'' carbon newtonian, an EQr6 pro, an EAF, an OAG and everything that is required to make serious OSC DNB imaging. I am interested in progressing but I won't buy Astrodon filters. This is out of budget. So, my options are i) what camera and iii) what filters (I will get a 7x36mm ZWO EFW anyway).

Camera : ASI294MM or ASI2600MM ?
I know the usual pro and cons of the 294 (calibration issue in NB imaging and amp glow for the 294). I am not affraid of those. However, the 2600MC offers some interesting advantage and seems to be less difficult to use. It is more expensive though. This is a 700$ increase in comparison to the 294.

Filters : ZWO newers filters plus a baader 6.5nm Oiii or better than this ?
I have currently honest results with my l-ultimate for Ha and Oiii and an Askar C2 to get Sii. No halos at all. I read that the ZWO newer filters are fine, with some remaining halos in the Oiii. The pricine is attractive. The Oiii might be replaced by a baader 6.5 nm which seems to be slightly better. But I see many nice images with the zwo filters.

I read quite much since three days. I tend to think that the 294mm still runs strong and that the zwo filters should be a good entry point in monochrom. Today's IOTDproves it. However, I am happy to read any comment that might help in decision making here.

Many thanks !

CS

Patrice

I've recently moved to mono and I've found a listing here on Astrobin Marketplace for Astronomik Deep-Sky RGB, SHO 6nm CCD and L-1 filters in 1,25" size. The camera I'm using is the Player One Ares-M (IMX533) paired with the Samyang 135mm.

I didn't notice any halos at all with the narrowband filters, but I still need to try the RGB filters. I replaced the L-1 filter with the L-3 filter to cut out imperfections in the deep blue and the deep red parts of the spectrum, but that is related to the lens and not the filters.

I would recommend the Astronomik filters if you find a good deal, they're great in my opinion.

As regards to the camera I would recommend the 2600MM, it's less picky about calibration and you'll have a larger FOV (and also more resolution if your skies support a finer sampling with smaller pixels).

Daniele

The zwo filters will do ok as long as you avoid areas with huge/bright stars. Orion, gamma cass etc. I used to get some very nasty halos and reflections with the NB filters.

I made the switch to mono a little over 3 years ago and I've never looked back. I have tha 294MM Pro camera which has proven very capable once I was able to master the finicky calibration frame procedure. The flexibility of having the Bin 1 and Bin 2 modes is nice but I am giving serious consideration to upgrading to the 2600MM. The extra FOV would be nice as well as not having to deal with amp glow. Every once in awhile, I fight a little bit of residual amp glow even after running my calibration frames so having cleaner data from the start would be nice.

I did go with 36mm filters so that I had an upgrade path for the future. My first set of filters were the Optolong LRGBSHO (7nm narrowband) and I found them to be more than adequate. I did get the itch to do a filter upgrade and I went with Antlia 4.5nm Ha and Sii with a 2.8nm Oiii and the Pro LRGB filters. I've been a bit disappointed with the 2.8nm Oiii filter as it sometimes exhibits weird artifacts after doing star removal. With the clarity of hindsight, I would have kept my Optolong LRGB filters as I have not seen a big difference with the Antlia Pro LRGB set. The Antlia narrowband filter upgrade was definitely a noticeable improvement. I honestly think a full set of the 4.5nm SHO filters would have met my needs in terms of striking a good balance between performance and price. Chroma's and Astrodon's are arguably much better but the sticker price on those is a tough pill to swallow.

Bob

Hi, Patrice.
First up, I shan't claim expertise when it comes to comparisions of filters as I have only one set and decided I would go with the best I could afford at the time.
That said, I have the Antlia 3nm NB and Antlia LRGB set, in a 36mm ZWO EFW (plus OAG and EAF).

Ditto with camera. Decided to get the best I could afford and not have to worry about the bottomless pit of upgrading (buy once and buy well). I have the ASI2600MM which works a treat. A bit oversampled on my EdgeHD 8", but a compromise I am prepared to wear, given that I also use it on shorter scopes as well (I have the OAG/EFW/Camera all screwed together as a unit and move it between scopes).

Albeit my images can't hold a candle to those of the many astro-virtuosos on Astrobin, I am well pleased with this setup and find myself not wanting to 'upgrade' anything (apart from scopes. Oh and maybe a new mount oneday, and perhaps a …

).

I hope that helps a little, Patrice.
Cheers.
Paul

P.S. Mono is a lot of fun. As Bob says, you won't look back.

Whatever filters you decide to go with, make sure to get at least 36mm in size as they work better with the larger frame cameras such as the 2600MM. I have 36mm Astronomik 6nm SHO, L2 and their RGB Deep Sky set in my EFW pairing up with the 2600MM. Mono will give you more processing options and requires more work but you will find out the results are well worth it.

Another point to consider with filters is to purchase a complete set from the same manufacturer as they will all be parfocal which makes focusing easier when swapping between filters and that initial focus using the Lum filter.

CS, Eddie

Hi Patrice.

ASI 2600MM looks to be the go to camera, It's large enough to cover a wide field of the sky, especially with your 8" and 36mm un-mounted filters.
Many imagers use the Baader CMOS filter sets. They don't break the bank either. Antlia filters also look good and a very good price.
Mono imaging will give you a lot more flexibility and the real benefit is your using all of the chip to gather photons in one colour or wavelength. You can mix and match filter combinations as much as you want to create your image.
Very frustrating at times as images take longer to make as you cycle through the different filters but the results are spectacular, You won't ever regret changing over

I used to use Astrodon LRGB and 5nm NB 36mm filter set with an SBig STF 8300 mono. The result were amazing.

IMX571 sensor and 36mm unmounted Antlia 3nm filters plus LRGB V-Pro.

Hard call here. Normally I recommend the 2600 all the way but you are an experienced 294 user so the MM shouldn't throw any curves at you. The 294 is actually a more sensitive camera, especially in Ha and with the larger pixels it is a faster camera. It also has the Bin1 mode (which your OSC can't do) which has lots of disadvantages like 12bit and shallow well depth but it gives your rig a sampling resolution just a hair under 0.6 arc seconds which turns your excellent 8" newt into a true, high res galaxy hunter.

The 2600 gives you a slightly wider view and great sampling at roughly 0.97 arc seconds so is better in many ways for most uses but it is more expensive and heavier.

If budget wasn't my main concern (A used 294M especially with 31mm filters is much cheaper) I would likely go with the 2600/IMX571 and Antlia 4.5nm filters. You can always dither and drizzle for the few times you think you might want more resolution and the rare occasion the seeing will let you get it.

On filters, your scope is fast. It is on the edge (or possibly beyond) what you can expect from 3nm filters and any error or shift in a set of 3nm filters will put you outside the band shift. If you ever want to use a Starizona Nexus, TS2Korr, TSNTRED then you would definitely be out the band shift. In my opinion, a 4.5nm set of filters is a safer purchase for a fast f/4 and faster scope. But, you already use an L-Ultimate so maybe I am completely wrong on this point.

Dear follow astrophotographers,

Many thanks for your very valuable inputs. Each post is truly appreciated.

At this stage, it is clear that the 36mm filters is the way to go. I am still hesitate between the 294mm pro with upgraded SHO filters or the zwo combo 2600mm+zwo filters, except for a baader Oiii (I do not care about parafocal as I have an EAF anyway).

I see that the consensus goes to the 2600mm that is regarded as larger, less capricious and more recent.

On the 294mm horn of my dilemma, I am very sensitive to the galaxy hunter argument by @Joe Linington. I like indeed galaxies are regret some poor results so for, except maybe for my M51. Unfortunately for this argument, I fear that I am here limited by my sky as I tend to have difficulties to increase sharpness at the moment. I am also skeptical about the idea that the 2600mm is "newer". It is, but not so much. The 294mm has even a better QE in the Ha area, while the 2600mm is better in the Oiii area.

However, what really plays a role to me is the hassle of calibration with multiple filters. With the OSC, renewing flats is not a big deal as I have basically three filters (Ha/Oiii, Sii/Oiii and uvircut). What takes me time here is not doing the flats, but getting my panel to output the light level that will allow me to get the required 28k ADU in 5 seconds exposures so that I don't have to redo each time the darkflat too. This is currently trial and errors and sometime a bit frustrating. Now thinking for doing this up to 7 times for each image, or more if recollimation is needed between the individual session seems to be too much. And this is really important to me. And that vanishes with the 2600mm.

So my question would be at that point : how often a newtonian user should redo flats ? should we really be that picky that as soon as a scope is recollimated, all flats are to be redone ? is that the case for all types of filters or only narrowband ?

Any feedback of ASI294mm user here would be much appreciated.

CS
Patrice

Ideally you take flats after each filter use or at the end of the imaging session. I usually take mine after each night (for every filter I used). You should also take dark flats.

patrice_so:
So my question would be at that point : how often a newtonian user should redo flats ? should we really be that picky that as soon as a scope is recollimated, all flats are to be redone ? is that the case for all types of filters or only narrowband ?

Patrice, new dust specs and any changes to your camera rotation can impact your flats. As a result, it's my opinion that the best imaging practice is to shoot new flats and dark flats at the end of every imaging session. I do this for each filter that I used during my session. The time required is minimal in the grand scheme of imaging. I reuse my darks but aim to replace them after 9 months to a year max.

Being a 294MM user, it's important to make sure your calibration frames match the Bin setting used while imaging. I switch between Bin 1 and Bin 2 depending on what scope I'm using and learned that not checking the right Bin setting leads to some bizarre looking stacks.

You don't need to use regular darks if you dither, just flats and dark flats.

Bob Rucker:
patrice_so:
So my question would be at that point : how often a newtonian user should redo flats ? should we really be that picky that as soon as a scope is recollimated, all flats are to be redone ? is that the case for all types of filters or only narrowband ?

Patrice, new dust specs and any changes to your camera rotation can impact your flats. As a result, it's my opinion that the best imaging practice is to shoot new flats and dark flats at the end of every imaging session. I do this for each filter that I used during my session. The time required is minimal in the grand scheme of imaging. I reuse my darks but aim to replace them after 9 months to a year max.

Being a 294MM user, it's important to make sure your calibration frames match the Bin setting used while imaging. I switch between Bin 1 and Bin 2 depending on what scope I'm using and learned that not checking the right Bin setting leads to some bizarre looking stacks.

Well, this is indeed what I do with my 294MC pro. I do systematically flats, trying to reach 5s exactly, so that I can rely on a library of dark flats of 5s. I do it exactly for the reason you mention. I also redo my darks and dark flats each year. That leaves me with the need to identify a solution to be more productive with my flat production. An ascom compliant flat panel could do for instance. Or simply a switch with discrete position so that I can avoid this - somtimes short, sometimes long - searching for the exact voltage that will deliver my 5s flats...

Your page is an advertisement for the 294mm @Bob Rucker !

But here is a nice inference : before buying the 294mc, I was aware and afraid of the dreaded bretzel issue. And after two weeks of adjustments, I no longer think of it, at all.

Robert Žibreg:
You don't need to use regular darks if you dither, just flats and dark flats.

Trust me, if you use a 294MM darks are absolutely necessary. The amp glow on this camera is insane but it does calibrate out.

I moved from the ASI294MC to the ASI2600MM and 3nm Antlia 36mm filters and don't regret the move. Sure, mono is a bit more fiddly (and, initially, expensive) but I believe it's worth it; I just feel the quality of the subs is better and you have ultimate control on what you're imaging. I don't take flats after every session, but maybe every week or two. I don't have a permanent set up, bringing the scope inside every morning after every session, but so far I haven't had an issue with not doing daily flats. If you use NINA, the flats wizard makes taking them a relatively pain free experience.

Frank

Frank Alvaro:
I moved from the ASI294MC to the ASI2600MM and 3nm Antlia 36mm filters and don't regret the move. Sure, mono is a bit more fiddly (and, initially, expensive) but I believe it's worth it; I just feel the quality of the subs is better and you have ultimate control on what you're imaging. I don't take flats after every session, but maybe every week or two. I don't have a permanent set up, bringing the scope inside every morning after every session, but so far I haven't had an issue with not doing daily flats. If you use NINA, the flats wizard makes taking them a relatively pain free experience.

Frank

Thanks @Frank Alvaro !

I use to do as you as I was using a refractor. However, the need to periodically recollimate a newtonian (fixed post, but under a cover) comes with removing the camera to put the laser instead. At this point the optical train is partially disassembled and good practice is to redo the flats.

I shoud try nina. For sure. But I like APT at the moment.

I use the older ASI1600MM pro and have been verry happy with it. You can usually find these with filters and a filter wheel on Astromart or Cloudy Nights for a reasonable price.

Eddie Bagwell:
Another point to consider with filters is to purchase a complete set from the same manufacturer as they will all be parfocal which makes focusing easier when swapping between filters and that initial focus using the Lum filter.

Absolutely not the case for MOST brands, regardless of what they say, the filters are very very rarely parfocal... I had a set of Astrodon 50mm round filters back in the day that were 100% parfocal, and I never had to adjust the focus even one step between any of them... but I've used 'Parfocal' filters from Astronomik and many other brands that have all required filter offsets to be employed to retain good focus after filter changes..

I personally would go for (and plan to do the same) the 294MM.

Yes - the 2600 is a superior sensor. better dark current, better read noise, better QE, smaller pixel size, no amp glow etc… the list goes on…
BUT - I have a IMX294 colour sensor now, and like you, I have no issues with calibration frames with it. They are fiddly until you get them right, then you forget about it again for the rest of time…

My 294 gives me 1.14"/px in my main imaging scope, which is absolutely perfect to me, its about 1.5x better than the average seeing conditions where I image, and with dithering/drizzle, I'm able to achieve incredible fine details in images..

I find that it's the perfect sensor size for me. I've had 35mm CCD's in the past, APS-C CCDs/CMOS cameras too… but I always prefer the 4/3rds format… I loved my KAF8300, the 1600MM and now the 294 colour. and hopefully in the coming months I'll get a IMX492 (294 mono) camera as well. I'll leave the OSC camera on the 65PHQ, and put the mono camera on my 120APO.

I think, if you know your way around the 294s calibration, and you like your current FOV/pixel scale - why change away from something that's working well for you?

I own and use both - it depends on what image field I want. Yes, the 294 is a bit fiddly, the amp glow is not enjoyable but the filter set for it is much less expensive than the one for the APS format. The amp glow is not a problem with proper darks and biases, the advantage to switch from 11MPx to 47MPx is an interesting option - which I use for lower focal lengths. The APS format however is more universal but for lower focal lengths a bit limiting due to the undersampling effect, which can occur.

If your budget permits, I would rather go for the 2600 - another reason is, that you can resell it easier than the 294 - IMO

CS
Georg

Hi everyone,

I thank you very much for your inputs. The match between the 294 and the 2600 was close and I saw many good arguments. Finally, I decided that, taking my focal length (800mm), the sky underwhich I operate, and the fact that the 294mc is much more demanding in term of calibration, which with 7 filters plays a role, I decided for a IMX571 mono sensor.

Looking then in detail, I found the TS-Optics version of the mon imx571 Touptek a a discounted price on TS website.
https://www.teleskop-express.de/en/astrophotography-and-photography-15/cooled-cameras-16/ts-optics-touptek-mono-astro-camera-2600mp-g2-sony-imx571-sensor-d-28-3-mm-17360

As I do rely on the ASIair, I ordered one, together with a 7x36mm filter wheel and a full set of Optolong filters (I know, this is a compromise).

I thank you very much for your inputs.

CS

Patrice

PS : this is not to say that the 294mc is not great : https://www.astrobin.com/0231ox/F/