Lee_P

Yes please, I'd be interested to hear if it's good!

Incredible image, bravo!

That's fantastic, 24 hours well spent! There might be some stacking artifacts or similar along the right and bottom of the image; worth cropping in very slightly?

+1 for ASI2600MC if you can stretch to that. It works well with the kind of wide-field refractors that you mentioned. Lots of example photos here. Echoing what others have said, it would be good to know exactly why you gave up on a Mono and OSC camera before, as it's likely that those issues will still exist. One bonus of a cooled camera that I don't think has been mentioned is the ability to create a library of calibration frames. That helps to make things a bit easier.

Welcome to SGL

Both look good, thanks for posting the comparison.

This is a great image, and thanks also for sharing your processing workflow. One quick question that may help me, re NSG: how do you choose your reference frame? I tend to just pick one that has the best Stars or FWHM rating, but is there a better way?

Incredible! 🤯

I've had a crack at reprocessing some data, trying to get a sharper result and more blue into the image -- often tricky with an L-eXtreme filter. It is sharper, but also quite noisy I got the blue in, though! More info, including the original attempt, here: https://urbanastrophotography.com/index.php/2021/07/29/the-pelican-nebula/ * June & July 2021 (reprocessed November 2021) * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Filter: Optolong L-eXtreme * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight, Topaz DeNoise AI, Lightroom * Control: ASIAIR PRO * 780 x 120 seconds Total integration time: 26 hours

That's good going for a short integration time! And good on you for maxing out your current equipment before upgrading. I second every suggestion made by powerlord, and would add in spend a bit of time making sure your focus is as good as it can be.

Thanks, I'd be interested to see your final image once you've tackled it

I've been using the Askar FRA400 for nearly a year now, and have written an updated review here: https://urbanastrophotography.com/index.php/2021/11/03/review-askar-fra400-f-5-6-quintuplet-apo-astrograph/ (I still think it's great 👍)

That's a potentially very useful site! I just tried it, but found the surface brightness section a bit tricky to fill in. Cartes du Ciel doesn't seem to have the surface brightness for most of the targets I'm interested in. Have you found any workarounds? Regarding your question, you can get by with short subs with the 2600MC. Guiding is useful though, least of all because it allows you to dither, which is more-or-less essential. So I'd say that if you can reliably get subs of a couple of minutes using your EQM35 with guidescope, then why upgrade?

Thanks, this made my day 😎 More Urban Astrophotography content is on the way, including a one year with the FRA400 review!

The new CMOS sensors are excellent. As Olly says, the ASI2600MC in particular is ace, especially combined with a dual-band filter like the Optolong L-eXtreme. Lots of examples on my website here. newbie alert does raise a good point though, that you need a lot of harddrive space. Fortunately that's not too expensive these days.

Thanks vlaiv, that’s helpful. Broadly speaking then, is it accurate to say that a larger aperture: * Helps a lot to increase resolution for planetary imaging; * Helps to increase resolution (i.e. sharpness and ability to separate close objects) for DSOs, but seeing and mount performance are also big factors; * Makes a faster system (i.e. lower focal ratio) possible; * Is important to get good quality all the way to the edges of a large sensor.

Ok, good point. Let's say the focal length stays the same. The focal ratio will be lower for the larger aperture telescope, given that focal ratio = focal length / aperture, right? Makes sense, bigger aperture means you're collecting more light. But then if you have the smaller telescope, you could just aim for a longer total integration time to then match the bigger telescope. So what are the other benefits? Increased resolution, i.e. being able to separate closer objects?

Ever find that as you gain knowledge, you start to question your understanding of more fundamental topics? I'm getting that right now. I wonder if someone would be so kind as to answer this question: assume you've got two telescopes that have very similar specifications, but one has a larger aperture than the other. The bigger one has more light-gathering ability; but what does that actually translate to in real terms for astrophotography? Shorter total integration time needed to get the same signal-to-noise ratio as its smaller counterpart? Sharper images? Something else? Thanks in advance!

Fantastic, no wonder you're happy! 😆

As part of my quest to push the limits of what a small refractor and OSC camera can achieve from a light-polluted city centre, I present my latest experiment: NGC 7822. More info on my website here, but if you're just interested in the capture details: * NGC7822 / NGC 7822 * October 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Filter: Optolong L-eXtreme * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Control: ASIAIR Plus, ZWO EAF * Software: PixInsight, Lightroom, Topaz DeNoise AI * 600 x 120 seconds ------------------------------------------------------------ Total integration time: 20 hours ------------------------------------------------------------ By Lee Pullen

Then it's... OSC: 1 for sale Mono: 0 for sale I'm not disagreeing with you -- rather, I actually think you're right -- but we have to be careful when using assumptions to draw conclusions as then we tend to reinforce our pre-existing notions. I don't think we can draw any solid conclusions just from the used market sales (especially not just the very brief research I did 🤣) without more information. If we guess that almost all those selling an older CCD or 1600MM are upgrading to a newer Mono, then of course we'll stack the deck full of Mono users. For what it's worth, I sold my 1600MM and bought an OSC

I've just done this, but speedily -- so my data won't be completely accurate! It's just for fun though... OSC: 11 for sale Older Mono (CCD): 18 for sale Modern Mono (CMOS): 10 for sale.

I quite like that way of looking at things: using the used market as an indicator. So out of interest I just went to UK Astronomy Buy & Sell, and filtered by the category "CCD equipment" (which seems to encompass CMOS too). I then tallied the OSC and Mono cameras for sale, just quickly: not counting guide cameras, and only cameras over £500 (as an indicator of quality). I gave up after the first two pages, but the results... drumroll... OSC: 11 for sale Mono: 28 for sale I was surprised by that. Obviously my method has a lot of holes in it, but it's still an interesting result. A lot of the Mono cameras seemed to be older CCD, so I think that perhaps the owners are selling up and maybe jumping to Mono CMOS?

Rarely does a day go by when vlaiv doesn't blow my mind 🤯 🤣

Both great images! If I had to choose, I'd go for the first one. It just looks a bit crisper.