the plague of the 80mm refractor

[alacant]

Hi everyone. I thought this was quite entertaining: http://astro.neutral.org/astronomy_blog/blog/item/2007/09/the-plague-of-the-80mm-apo-refractor

Before I joined I looked through the posts and wondered why everyone copied a long list of equipment they owned in to every post they made. I thought you had to have an 80ED, a 200p or a 130 pds. Unless of course you had €40000 of kit anyway (sic)!

Only joking... 

 

[Alien 13]

Nowt wrong with 80ED refractors apart from them being so big, I wish more manufacturers would produce 60/50/40 mm APOs.

Alan

[Paul73]

What an odd rant. Technically, I'm sure that the author knows what he is talking about. But, to dismiss others efforts as "boring" is just plain rude. Sure, he may be able to afford £1,500 for a faster scope......

I do have SW ED80 in my equipment list. It is used very happily for visual only.

To say that I have limited knowledge of imaging would be an overstatement. So if I have missed some "imaging" humour, I appologise.

Paul

Ps. I enjoyed Alacant's observation re the signatures.?

[Stu]

Hmmm, seems like he is missing the point somewhere along the line!

[ronin]

Seems a bit of a strange read. Why 80mm refractors, really the answer is simple - people want them. Bit like the way that 8x42 binocuars are the main ones for general viewing, they are a bit of a size many would not expect to have come out on top. An 80mm does many things, not the most massive aperture, not the highest magnifications, but they do most aspects reasonable. Very much a jack of all trades, master of none. Strangely I suspect that that is why they are fairly popular.

At some time the reports says "How many 80mm APO images of the North American Nebula do we have to sit through every summer?" Does the scope only ever point at the NA Nebula? I thought that it was the imager that selects the target, and then images it. And yes here we will gets dozens on M42 images in about a months time, and I feel the same "Another M42!!!"

Then they say: "The final thing that winds me up about cheap refractor images are the stars.". Seems to have changed talking about an 80mm apo, or an 80mm ED to a cheap 80mm which I assume is an Achro - their ST80 I guess that they used for guiding. I am not aware of what I would term a cheap 80mm apo, Most are up at the £1000 mark.

The bit: "If course, they don't go much faster than F6. Getting good colour correction and a flat field faster than F6 is tricky. So usually you need a very expensive reducer to make the scope work from an astrophotography point of view." manages to ignore that if you have a fast reflector you need a very expensive coma corrector. So just work out which expensive accessory that it is you need, but either way you need one.

At the end anyone could make up a list of problems of a Newtonian or an SCT and along much the same lines as made in this artical.

[Moonshane]

In a way I can actually see his point. Yes, he’s a bit blunt and slightly rude/insulting but what he is saying is basically correct I think. F7.5 is rather slow for most imaging (I believe!). It is an astrophotography blog so will always be biased towards that rather than visual. What he seems to fail to appreciate is that when your budget is tight you can mitigate possible problems and wasted money by following tried and tested routes to success. Only then can you start experimenting and almost everyone goes through an evolution with their kit be that either through accruing more funds or by enhancing their practice.

Perhaps he has forgotten the pride of producing your own first ever DSO image which is naturally going to be the same as most others (not many DSOs change over a lifetime!). But it’s yours.

[Paul73]

Hope that the author isn't an SGLer...

Maybe his normal readership are hardened imagers who like a place to vent; then spend ages on more inclusive forums (such as SGL) helping and encouraging the "real guy budget" 80mm'ers improving their images?

Paul

[Chris]

I'm wonder what @ollypenrice makes if this blog entry.

The reason I think the ED80 f/7.5 is so popular for imaging is because it is remarkably well corrected for an affordable ED refractor. Anyway most imagers reduce them down to f/6.3 - f6, the cheap Altair .8 works really well if the user doesn't want to spend double on the matched .85.

The ED80 is a great size for grab and go too  

I wonder what the author uses?

[ollypenrice]

Ho hum, this lands on my screen in timely fashion since I'm working on a magazine article arguing pretty much the reverse. For obvious reasons of cost the blogger is correct that high resolution images are rarer than widefields on the forums and Readers' Images pages. But here's the thing: no amateur anywhere in the world is going to reveal any new small scale detail in the small tagets out there. None of us can take on the Hubble or Subaru and that, alas, is that.

When the amateurs reveal new sights in the sky they are either large or very large. Let's list a few. The Integrated Flux Nebula. The Squid Nebula, OU4. The Soap Bubble Nebula isn't tiny. The deep Ha backgrounds around the Double Cluster and the Cocoon, revealed so magnificently by Fabian Neyer.

http://www.starpointing.com/ccd/cocoon_pano40.html

And dare I list the Breaking Wave Nebula discovered (perhaps?) by those two reprobates O'Donoghue and Penrice? 

Contrary to the thrust of the blogger's argument, it is IC 59 and 63 in the image above which have been done to death at longer focal lengths, and the global wave structure which may be new.

All the images to which I allude are easily within the grasp of an 80mm refractor.

And then there are the amateur widefield mosaics which have brought together, and reavealed as interconnected, objects formerly regarded as discrete. Orion has been transformed into one vast nebula. Look at the Ha around Sadr. 'Around' is rather a loose term given how far rom Sadr it reaches.

So if, you want to find something new, should you work with C14 or an 80mm refractor? It's a no brainer.

Olly

[ChrisLX200]

Tom uses a large reflector (not sure - maybe 16") on his home-made mount and also... a Tak Sky90 He's a very knowledgeable/capable machinist and his DIY mount produces excellent astro images. I guess everyone is entitled to an opinion and folk can pick fault with his expressed viewpoint as they see fit. I agree that the budget 80mm refractor is never going to be the last OTA the budding astro-imager is going to buy but it is a 'known quantity' when it comes to producing images and because of that is very useful for learning the tricks of the trade. There are so many things to learn that it's nice to have something dependable (like the 80mm OTA) which means there is one less thing to require tweaking along the way. Yes, the image scale will be the same as all the other 80mm f/7 refractors out there but there are also many other skills that contribute to the final image that there's plenty of room to make your own result stand out from the crowd. When the time comes you need more reach for smaller/fainter objects then buy the larger instrument.

ChrisH

[ollypenrice]

I trust that my own response comes across as good natured banter. I don't want to participate in mortal combat as practised elsewhere!!!

Olly

[RichLD]

If we were all as well resourced, committed and talented as the blog's author then surely he'd be venting about how boring all the images are taken with 16" reflectors etc. The post is probably engineered to create a backlash (no mount type pun intended) anyhow, so I leave it there rather than feed into it.

Quite rude and not very British if you ask me 

[DaveS]

I *like* boring 'scopes. Boring means the 'scope just plain WORKS. No faffing around with hyper-critical collimation or squaring-on issues.

Why the heck do you think you see so many ED80 / HEQ5 rigs? They just plain work! For a beginner it's really a no-brainer. When you've honed your skills on this relatively affordable rig, then move on to the more exotic stuff, but be prepared for "fun and games".

 

Oh yes, the TEC 140 is an f/7 'scope, so there!

[Gina]

Have to say I'm delighted with my SW Esprit 80ED Pro - a really superb piece of kit with amazingly flat field with its field flattener and at f5 it's faster than that article quoted for 80s

[johnrt]

What an odd rant that is. Don't want to look at lots of images of the NA Nebula every summer? Well don't look at them then, nobody is forcing you to.

I have encountered the author of this blog on another forum, not SGL, and found him to be no less abrasive and curmudgeonly as he comes across on his blog.

Perhaps he's just a modern day.....

[ChrisLX200]

It's funny, but I find looking at each year's crop of objects like the NA neb and M42 taken with an 80mm to be very useful in monitoring the development of new kit. New scopes (by that I mean optics), new cameras, new processing software and techniques (lucky imaging?) - the image quality a beginner can achieve these days surpasses that which could be obtained years ago even by experienced imagers. It will be interesting to see how the likes of ASI1600MC and its derivatives when attached to an 80mm 'frac will perform over the following years, it's getting close to 'point and click' already on the brighter nebs with less need for long duration exposures.

ChrisH

[ollypenrice]

2 hours ago, ChrisLX200 said:

It's funny, but I find looking at each year's crop of objects like the NA neb and M42 taken with an 80mm to be very useful in monitoring the development of new kit. New scopes (by that I mean optics), new cameras, new processing software and techniques (lucky imaging?) - the image quality a beginner can achieve these days surpasses that which could be obtained years ago even by experienced imagers. It will be interesting to see how the likes of ASI1600MC and its derivatives when attached to an 80mm 'frac will perform over the following years, it's getting close to 'point and click' already on the brighter nebs with less need for long duration exposures.

ChrisH

I know what you mean. When I look at our two volume Dob bible, Kepple and Sanner's Night Sky Observer's Guide, I feel a pang of anguish for those most expert fillm astrophotographers who were gas-hypersensitizing Tech Pan film out in the field, guiding by hand for half an hour and getting results which seem disastrous if judged by the standards set just one generation later. I imagine that what we are doing now will suffer a similar fate - but it's the doing which counts. And I certainly take my hat off to the old school Tech Panners.

Olly

[daz]

I can't take that rant seriously - another one that calls it North American nebula, when it is the North America nebula!

[Knighty2112]

It's a 'frac! What's not to love!  

[Alien 13]

There have been a few realy jaw doping images on SGL one was a widefield interactive 360 panorama with a camera lens another a meteor breaking up maybe we do need to get more creative with modern tech.

Alan

[Paul73]

48 minutes ago, Alien 13 said:

There have been a few realy jaw doping images on SGL one was a widefield interactive 360 panorama with a camera lens another a meteor breaking up maybe we do need to get more creative with modern tech.

Alan

Too right. From my very limited understanding of imaging. The kit will only get you so far. From then on its down to the astro dude ......

Paul

[mikeDnight]

Sometime back in the 1990's or possibly early 2000's, a fine fellow in the USA managed to discover a new nebula in Orion. The scope he used was a 78mm Tak fluorite, which I think had a F ratio of around 8. The article in the Op mentioned bloated bright stars produced by these small refractors. Personally I'd prefer slightly bloated brighter stars rather than stars monstrously distorted by spider diffraction,  or the photon splattered blobs often produced by SCTs. 

Mike ?

[iPeace]

I'd like to apologize on behalf of all who have the unmitigated gall to enjoy this pastime and share their hard-earned results without making an effort not to bore this particular person...but I just can't be bothered.

[RichLD]

On 09/09/2016 at 09:37, ollypenrice said:

When the amateurs reveal new sights in the sky they are either large or very large. Let's list a few. The Integrated Flux Nebula. The Squid Nebula, OU4. The Soap Bubble Nebula isn't tiny. The deep Ha backgrounds around the Double Cluster and the Cocoon, revealed so magnificently by Fabian Neyer.

http://www.starpointing.com/ccd/cocoon_pano40.html

Off topic so apologies in advance. Thank you Olly for pointing me and others in the direction of Mr Neyer's website - his images are ridiculously good 

This one in particular caught my eye - good grief it's brilliant!

[alacant]

So many replies. It must be cloudy! Thanks everyone for posting. I thought I'd get the wrong gist, but it seems not. I still think however that it's quite easy for us to forget that we all started out at some stage as newcomers. The temptation is to jump in and answer questions in the getting started section as if those getting started were already started. It can get really confusing if others then take over the thread and start talking about something else which is totally over your head. Thanks to the posters here for recognising that. If it is off topic it's good for us beginners to know that. Otherwise you're left feeling inadequate. As a beginner, I need experts and I am indebted to the patience of all those who have answered my questions here. Thanks and clear skies.