Starfront observatory mono vs OSC

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eric belanger avatar

Hello everyone.

Im planning on sending a rig to starfront observatory. I think i want to go with an OSC setup with filter wheel (l-pro filter , antlia ha-oiii , antlia oiii-sii ) and 2600mc

I was wondering if the difference in image quality would be pretty noticeable ? Between osc and mono ….from bortle 1-2 !

I know from city , bortle 7 , like where i am . I get better results with mono , but from a dark sky….is it less obvious ?

Thank you :)

Arun H avatar
You have a 2600MM Pro and Narrow band filters. 

I imagine the reason you are going with a MC and dual band filters is cost?

Honestly, if it were me, I'd buy myself a set of LRGB filters for the MM and send that set to Starfront and do the dual narrowband stuff from home in B7 using the B1-2 site to differentiate on LRGB. 

The great benefit of imaging from a dark site it to gather "L" data from a mono camera and go deep. 

But the real key is the access to the dark site and either setup will get you very good images.
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Craig Rairdin avatar

eric belanger · Oct 28, 2025, 11:03 PM

Hello everyone.

Im planning on sending a rig to starfront observatory. I think i want to go with an OSC setup with filter wheel (l-pro filter , antlia ha-oiii , antlia oiii-sii ) and 2600mc

I was wondering if the difference in image quality would be pretty noticeable ? Between osc and mono ….from bortle 1-2 !

I know from city , bortle 7 , like where i am . I get better results with mono , but from a dark sky….is it less obvious ?

Thank you :)

I shoot OSC at Starfront with an Askar 71F w/.75 reducer, ASI2600 MC Pro, and filter wheel. I don’t have any experience with mono, but here’s my take.

  • Bortle 1 makes both OSC and mono better than the same configuration under Bortle 7. From a pure quality standpoint, the difference between OSC and mono is greater under Bortle 1 than it is under Bortle 7.

  • DELETE: Mono requires 3x to 5x more total integration time than OSC . It still does under Bortle 1, EDIT: Mono imagers often spend more time imaging than OSC imagers, due to significantly more filter changes, the need to shoot more flats, and the fact that more integration time in mono yields significantly better results than OSC. At Starfront, good imaging nights are more common than non-imaging nights, so there’s more total time available to shoot mono. You’ll get more done in less calendar nights.

  • The same principle applies to OSC. I shot about 102 hours of narrowband on the Bat and Squid Nebula in 23 sessions over about 42 days in July and August. It would have taken me forever to get 100 hours at home.

So both mono and narrowband benefit from Bortle 1, but in terms of quality, mono benefits more. The arguments I use to justify OSC don’t change based on sky quality — it’s still easier and takes less time. But if we’re talking quality, mono is still going to win, and it’s going to win more obviously.

If you end up sending an OSC setup, let’s talk about filters.

  1. I don’t think you need the L-Pro at all. There’s no light pollution so you’re just throwing away photons.

  2. I like your Antlia filters. I shoot with just an Optolong L-Ultimate — it keeps things simpler. But the two dual band — or a good triband — will be great.

  3. Add a dark filter. It will let you shoot darks during the day when the roof is closed and have a better chance at it working well.

On a related topic, strongly consider a Deep Sky Dad OFP2 motorized flat panel. The O at the beginning is for “observatory” and it was designed for use at Starfront. The reason is that the flap slides down and away from the scope as opposed to flipping outward. This keeps your swing radius virtually the same. They’re the only flat panels permitted on mini piers for that reason. Furthermore, they are designed so the light doesn’t turn on unless the flap is closed. This prevents you from lighting up the whole building when others are trying to shoot darks. The reason I said this is related to filters is that you can shoot darks with the flap closed and the light turned off. This, combined with a dark filter in your filter wheel, gives you a lower chance of light getting in and ruining your darks.

The flat panel makes it all-around easier to shoot flats. You don’t have to time it just right to take “sky flats”. Just do them before you start imaging or after your done. Easy.

eric belanger avatar

Thank you so much.

It's very well explained. Good thing to know about the flat panel . Thanks a lot .

I was thinking OSC , specially for broadband targets. Just one filter instead of lrgb .

Anyway. I Will keep thinking about it .

Thanks Again :)

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Craig Rairdin avatar

Feel free to join the Starfront Discord and ask questions there. They also have special voice and video hangout sessions for first-timers to answer questions about shipping and what to send. But just asking questions in the general channels will also get you answers.

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Arun H avatar
Craig Rairdin:
mono requires 3x to 5x more total integration time than OSC. It still does under Bortle 1, but at Starfront, good imaging nights are more common than non-imaging nights, so there’s more total time available to shoot mono. You’ll get more done in less calendar nights.


I am sorry - the notion that mono requires 4 to 5x more integration time than OSC is a completely fact free statement and not supported by any kind of scientific or evidential backing. This is just very bad advice; it is incredibly bad advice.

Don't take my word for it - as Jeff says below, research the issue. Take advice from people that actually know what they are talking about - people like John Hayes who have extensive optical background, or people like Timothy Martin who have tons of spectacular images to their credit.
Jeff Rothstein avatar

Arum is right. This isn’t the place to hash out the issue—you will find many resources online that explain it. Just be careful about your sources. There’s a lot of incorrect info out there.

Enjoy Starfront!

Jeff

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Craig Rairdin avatar

Arun H · Oct 29, 2025, 12:37 AM

Craig Rairdin:
mono requires 3x to 5x more total integration time than OSC. It still does under Bortle 1, but at Starfront, good imaging nights are more common than non-imaging nights, so there’s more total time available to shoot mono. You’ll get more done in less calendar nights.



I am sorry - the notion that mono requires 4 to 5x more integration time than OSC is a completely fact free statement and not supported by any kind of scientific or evidential backing. This is just very bad advice; it is incredibly bad advice.

Don't take my word for it - as Jeff says below, research the issue. Take advice from people that actually know what they are talking about - people like John Hayes who have extensive optical background, or people like Timothy Martin who have tons of spectacular images to their credit.

Let me clarify my statement — I prefaced my entire comment with the statement, “I don’t have any experience with mono”. My “3x to 5x longer” statement was very badly phrased. It certainly doesn’t require 3x to 5x more integration time than OSC. Perhaps the best way to put what I was trying to say is that there is a lot of overhead associated with shooting mono, and people tend to spend more time on a target because there’s more quality to be had from a mono workflow than OSC. Even if that isn’t true, the argument that Starfront gives you more time to be shooting than most people have at home is true. Whether you spend that time shooting more frames or swapping filters, it’s still more time.

The conclusion I came to was unrelated to this “incorrect fact”. What I said was that both OSC and mono benefit from dark skies, but that mono benefits more. The original question is whether OSC would be enough better to be less noticeable when compared to mono. My answer was no.

The rest of the answer was related to “if you decide to go with OSC…”.

You’re absolutely correct that I didn’t show my math and that I’m not an award-winning astrophotographer. But that was never the issue. A question was asked in an area that I have some experience in. Nobody said “only accredited scientists and award-winning photographers may respond”. A person asked for opinions in a forum that exists for that purpose. I gave one. We all agree that my answer was correct (mono wins, even under Bortle 1) even if a small part of my reasoning was not.

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Arun H avatar
Craig Rairdin:
It certainly doesn’t require 3x to 5x more integration time than OSC.


I think you were very specific. Here is the quote from your original comment. You mention "requires" and you mention "integration time". You are backtracking now. 
"Mono requires 3x to 5x more total integration time than OSC. "


You are correct - this is an online forum. Anybody can give any advice. It does need to be based on fact.  Hence my advice to the original poster to be careful who he takes advice from. 
A question was asked in an area that I have some experience in.

You yourself claimed " I don’t have any experience with mono,"

Your lack of experience did not prevent you from giving bad advice and making the bold statement, completely devoid of scientific support, that mono requires 3-5x the integration time of OSC.

In the end, it is up to the original poster to do with what he wants. I notice that he thanked you for the bad advice, but did not bother to acknowledge me of Jeff who gave him advice based on experience and science. Whatever. It is his money.
Craig Rairdin avatar

Just to wrap this up — I edited my original post to clarify the statement Arun keeps harping on, even though I apologized for it and corrected it previously. The moderators deleted my most recent post in which I apologized again, and in which I pointed out that everything that he/she keeps bringing up was previously acknowledged and didn’t affect the conclusion I had come to. Hopefully the edit will clear it up, and hopefully this third apology will pass muster, unlike the last one.

Bill McLaughlin avatar

My take is simple.

Can you get good results with a color camera?

Yes, at least for many objects.

Can a color camera ever equal the overall versatility and capability of monochrome?

No.

It is the capability and versatility that makes monochrome the winner. I had a color camera for a while and now only own 4 monochrome cameras at two sites and no color cameras (unless you count my seldom used DSLR).

My take is that color is good for demos and educational purposes but I would never use one for my own imaging as it forces too many compromises.

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andrea tasselli avatar
Just the opposite of my reading but then I don't have to pay (extra) for sky-time. If I had the option (and when I had the option) I would chose an OSC camera over the Mono equivalent for most objects and certainly for wide fields (i.e., bigger than 2 square degrees). It is not like this is a paid-for pursuit for nearly any of us, is it?
Arun H avatar
Bill McLaughlin:
My take is simple.

Can you get good results with a color camera?

Yes, at least for many objects.

Can a color camera ever equal the overall versatility and capability of monochrome?

No.

It is the capability and versatility that makes monochrome the winner. I had a color camera for a while and now only own 4 monochrome cameras at two sites and no color cameras (unless you count my seldom used DSLR).

My take is that color is good for demos and educational purposes but I would never use one for my own imaging as it forces too many compromises.


Hi, Bill, you are correct, of course, which is why I recommended the OP send the mono camera he owns to the dark sky site along with a set of LRGB filters.

I own two mono cameras an one color. I use them for different purposes. My color camera is currently attached to the scope which I use to take with me to dark sky sites. Attached to a good scope, it gives surprisingly good results, and there is undeniably a convenience aspect to it. If I had limited or unknown time available on a target, there is value to this convenience. It is also, of course, considerably cheaper than a mono plus filter set of similar size.

The kit I will send to a remote site with an abundance of clear sky time will be the LRGB/mono combination to take advantage of luminance capture. And of course, narrow band is better captured using mono.
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Gilmour Dickson avatar

Under B1, given enough integration time OSC can get very very close to mono. Of course mono is always going to be superior. If I had a 2600mm set up and a 2600mc set up then the mm would go to star front for sure. Not even a debate for me. Especially as for the OSC rig you are going to go with a filter wheel anyway. At this point the mm may as well go!

But for me, under B1 skies, the osc compromises are such that the added cost and complexity of acquisition equipment, steps and time in processing are such that mono for me is not worth it. Especially as I am not a huge NB palette fan anyway.

An example of how B1 skies can allow OSC to become really, really close below. Josh and I imaged the same target almost at the same time. And not that differing integration time. Quite different equipment. His is better. His is mono. I am not saying OSC is the same. Just that it can be close. Which is just another data point for the OP. Although if he already has the mono equipment then as I say it is kind of a moot point.

Mine:

[URL=https://astrob.in/tvq8gg/D/][IMG]https://astrob.in/tvq8gg/D/rawthumb/regular/get.jpg?insecure[/IMG][/URL]

Josh’s:

[URL=https://astrob.in/c775v1/0/][IMG]https://astrob.in/c775v1/0/rawthumb/regular/get.jpg?insecure[/IMG][/URL]

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Makrem Larnaout avatar

That’s a great setup choice, the 2600MC is an amazing camera, especially under dark skies! 🌌
From my experience, the gap between mono and OSC becomes much smaller once you’re imaging from Bortle 1–2. The signal is strong, gradients are minimal, and color calibration is easier.

Mono will still have an advantage in flexibility (true narrowband mapping, better control of each channel, and slightly higher resolution/SNR), but under pristine skies the OSC + filters combo can deliver stunning results especially if you process carefully and integrate long enough.

If you want simplicity and remote reliability, OSC is definitely worth it. If you’re chasing the last few percent of depth and detail, mono still wins.

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