Do widefield astro images rule?

[gregbradley]

I have noticed for a long time in my own and other's images that usually widefield astro images are usually more popular than longer focal length images (up to a point).

By widefield I mean something like an FSQ and a full frame camera. 70-106mm and full frame.

The 10 inch F4 Newt/ASI1600 type setup is still reasonably widefield and is images from them are also quite popular.

What do you think? A high resolution widefield image has a lot of appeal.

Greg.

[gregbradley]

Noone wants to comment?

Do you think widefield images rule or do you prefer longer focal length images?

Greg.

[multiweb (Marc)]

What do you mean by rule? IMHO You never get the level of fine details you can access at long FL with a wide field set up like an FSQ or other refractor that gives you a couple of degrees field. Even with a sensor that has small pixels like ~3um you'll still get better details at 3m and over with a sensor that's 5um or more. It is also my experience that for a similar FL aperture plays a big role. FSQ is ~530mm and the hyperstar on the C11 is the same FL. The FOV is very similar, yet for all the optical sharpness of the FSQ the C11 on axis still levels it nicely. Years back Jase started doing high resolution mosaics to mimic widefield coverage. If I had a permanent setup that's what I'd do.

[The_bluester (Paul)]

I prefer both, so to speak. I really like the image scale of my 80mm, but imaging a planetary nebula with it would be an exercise in futility. The SCT will eat it for that sort of target. Pity I just gave that to my son!

[ChrisV (Chris)]

With my budget wide field rules. I suppose wide field is anything over 1deg, or maybe it's all relative.

[Camelopardalis (Dunk)]

I saw widefield, and to me that is 200mm or less

My sentiment is that there's something interesting at every focal length...

[Paul Haese]

I am more inclined toward image scale these days. With the right diameter of course. My preference for image scale ranges from 0.85-1.64. Imaging with one of my AG12's and the QSI gives me an image scale of 0.94". This effectively gives me a similar size image to ones taken with my RC and a 9 micron camera. The other AG is working with my STXL11002 which has 9 micron pixels and does give a pretty wide field of view but not to the same effect as an FSQ and the same sensor.

Do wide field images rule? Well that is highly debatable. Bit hard doing galaxies with an FSQ and even a 8300 sensor. I know I tried. I do know one thing though, wide field images don't tend to show a lot of errors with guiding and mount problems or even collimation. They are great for extended objects. That might be more popular to the masses. You get quick bang for buck and not much fussing around.

Ultimately it is horses for courses. Personally I like working with what I have now, albeit still with some problems but I get results which is what I want.

[Nikolas (Nik)]

I like both depending on the target and the equipment

[gregbradley]

Yes I am sure we all like various types of images and that's one thing that makes this pursuit so interesting- there seems to be a never ending improvement in available equipment and various ways to image the same objects.

Its just the widefield images tend to be more popular/win awards as opposed to galaxy images despite them being very interesting.

I guess NASA APODs tend to be a broad mix. So its not a clearcut thin perhaps more of a tendency for an image to be popular if its widefield.

Greg.

[leon]

Absolutely Greg, IMHO when I was imaging there was nothing better than a wide field of my chosen area of the night sky.
However having said that I do admire some of the great work done by the long focal imagers here.

Leon

[Andy01 (Andy)]

Personally I think focal length is not relevant here - in my opinion great images exhibit a combination of three key criteria.

Technical
Processing
Creative

Of the three above, the one most often overlooked is Creative....

Specifically:

Impact
Emotion
Story
Pareidolia
Composition
Rule of Thirds
Subject Placement
Colour Palette
Technique
Research

Get most of those right and an image will likely score well in competitions, regardless of focal length.

Cheers

Andy

[The_bluester (Paul)]

I think I would go back to my original post above, and extend it a bit to agree with Dunk. There are objects for every image scale that is practical to capture, and by image scale I mean area of sky covered by the image rather than pixel scale, though that is important too.

[multiweb (Marc)]

Originally Posted by Andy01

Personally I think focal length is not relevant here - in my opinion great images exhibit a combination of three key criteria.

Technical
Processing
Creative

You'll find that technical gets pretty challenging very quickly with focal length and possibly costly. You get an easy bang for the buck with a two degree field at ~3asp. Seeing becomes much less of an issue. You can play with large structures and enhance contrast and colors because the fine details don't cover many pixels. This is why widefield is more popular IMHO.

FL is very relevant because the deeper you go the more there is to see and visual perception takes a back seat. It becomes more about stellar profiles, real details and color separation. You try to get to the next level of details. Seeing becomes the main issue that you have no control over. Your mount becomes an important piece of the puzzle.

Personally it's a natural progression in the hobby. I believe it might be for a lot of other imagers who have been around for a while. You just want to try and see what's up close.

We all do this for different reasons but if competitions are an important part of why you do it then certainly widefield is easier to get a gong for.

[Sunfish (Ray)]

I have often thought that a mosaic of high resolution shots would be good.

What kind of permanent set up do you think?

I have just tried the cat at 1000 f5 and it is quicker and frames better than 600 f6 . But the lobster is cut off, so more scopes is better.

Originally Posted by multiweb

What do you mean by rule? IMHO You never get the level of fine details you can access at long FL with a wide field set up like an FSQ or other refractor that gives you a couple of degrees field. Even with a sensor that has small pixels like ~3um you'll still get better details at 3m and over with a sensor that's 5um or more. It is also my experience that for a similar FL aperture plays a big role. FSQ is ~530mm and the hyperstar on the C11 is the same FL. The FOV is very similar, yet for all the optical sharpness of the FSQ the C11 on axis still levels it nicely. Years back Jase started doing high resolution mosaics to mimic widefield coverage. If I had a permanent setup that's what I'd do.

[Peter Ward]

I frankly am bored by the vanilla view you get with wide field instruments. Sure, there is a vast continuum in the image quality and depth of popular, and not so popular targets, but the image scale is soooo repetitive.

Moving up the focal length scale is a challenging, but in doing so you discover a gelato-shop full of colour and flavour that makes vanilla look ordinary.

You need a big sensor to cover a reasonable field of view at focal length of 3400mm. Getting at perfectly corrected field across a 50mm diagonal, with no edge distortions or camera tilt is also costly and difficult. Any tiny glitch in tracking, or system rigidity rears its ugly head and produces eggy stars in good seeing and in poor seeing, they bloat into fuzz-balls.

The up-side is you can highlight really interesting structures that are barely hinted at in wide-field views.

As for resolution, I have yet to take an image with my 305mm F3.8 system that matches the fine details that my 400mm F8 system can capture. "nearly as good" does not cut it IMHO.

That said, ultra wide and deep views can be really interesting, particularly when you mosaic multiple frames (read: lots of work).

But to answer your question does wide field rule? I'd say not, and have the runs on the board to back that view up.

[multiweb (Marc)]

Originally Posted by Sunfish

I have often thought that a mosaic of high resolution shots would be good.

What kind of permanent set up do you think?

I have just tried the cat at 1000 f5 and it is quicker and frames better than 600 f6 . But the lobster is cut off, so more scopes is better.

Well ideally I would like to have another mount a bit bigger than my G11 that could support my C11 and my CN-212 in a more permanent setup. I have relatively small sensors which in itself is good because it's easier to have a good flat field with minimal tilt.

Lately I've been imaging around 2.5m and it's been tedious with setting up and my mount and a little frustrating with the seeing conditions but I'm working on it. Luckily I have the FSQ at ~500mm and that's great for travelling and using my OSC so I can still get my fix. I really enjoy getting around out west.

[The_bluester (Paul)]

Originally Posted by Peter Ward

That said, ultra wide and deep views can be really interesting, particularly when you mosaic multiple frames (read: lots of work).

That is much the direction I am heading, but as you say, they tend to be a lot of work.

I started a big mosaic early this year (As soon as I could get an hour on the target above 40 degrees altitude before the end of astronomical night) and it has turned into a two year project due to the weather.

Now complicated by changing cameras, I will hopefully get some data this time around the sun to restart with the new camera and finish it off next year. Even with 5 minute subs and an an OSC camera, when you want a minimum of 70 GOOD subs per panel, 12 panels or more is suddenly a big job.

[LewisM]

Either, eether. Both are great, depending on the subject.


I generally like images that show the object, but also show a good star field/H-a expanse to really get a sense of it's "place in space".


Up close and personal is great for the detail, but a little over-whelming in terms of scale, unless like Peter says, your sensor size allows a nice vista with it.

[Stonius (Markus)]

I think you're right, on the whole. People tend to be more impressed by the wider field images because they have more detail.


Unless of course, they're from Hubble, but those images look great because, well, see above.


Markus

[gregbradley]

Originally Posted by The_bluester

That is much the direction I am heading, but as you say, they tend to be a lot of work.

I started a big mosaic early this year (As soon as I could get an hour on the target above 40 degrees altitude before the end of astronomical night) and it has turned into a two year project due to the weather.

Now complicated by changing cameras, I will hopefully get some data this time around the sun to restart with the new camera and finish it off next year. Even with 5 minute subs and an an OSC camera, when you want a minimum of 70 GOOD subs per panel, 12 panels or more is suddenly a big job.

With mosaics you want to keep it a bit shorter so you can image the whole mosaic over a few days as things move in the sky and start to rotate.

I have had success doing 2.5 hours per panel and take each panel around the same time each night and same moon conditions. Then they go together nicely.

That's where a relatively fast system and sensitive camera helps a lot.
Also where a large sensor is really helpful.

Greg.