Stub Mandrel

There's an astro-modded 450D with very low shutter count in the classifieds. While not the ultimate imaging camera the 450D is capable of great results (IMHO).

Just for the record, someone posted recently asking 'the astrophotography question' with a budget of $500 or $1000 if they wait. One of the responses, by an experienced and capable imager and clearly intended to be encouraging, included the following: Surely this is exactly the sort of advice that is no longer accurate and is just going to put off most beginners?

I doubt it, to be honest. I know plenty of traders in the model engineering world, and to them the best thing that has happened to the hobby is the emergence of affordable, modest-capacity Chinese machines of serviceable quality. These bring so many people into the hobby the benefit from increased volume of machinery sales and more sales of accessories. Most importantly, the increased flow of people who previously thought they couldn't afford it into the hobby actually generates more sales at the top end as a significant proportion of them do decide to upgrade and extend their skills/capacity. Any retailer can figure out that this isn't competing with top-end imaging, it's opening up imaging to people who otherwise would have been restricted to visual astronomy. It also means they are much more likely to find success, and then go on to buy more advanced or capable kit. Another outcome is that you reduce the number of complete beginners going out and buying top end complex kit and failing to get anywhere with it. I'd lay money that the margins are better on accessories than scopes and mounts. A retailer who gets someone off to a good start with an economic scope/mount deal will make most of their returns as that satisfied customer develops their hobby and comes back for more goodies. Sell someone a super-dooper-sky-grabber-deluxe that they can't get to work, and you may never hear from them again. If getting lots more people into imaging is the end result it HAS to be good for the hobby and what's good for the hobby is good for the trade.

I'm not trying to muscle out the Alt-Az bit. Just searching for a formula that not only creates a home for discussing alt-az issues, but puts the technical issues relating to the mounts in a specific section within a wider topic that also covers the common ground with small scopes/DSLRs/EQ mounts that can get lost in the rest of the forum. Unfortunately 'budget' is an emotionally charged word and some people may read it as doing things on the cheap. For me trying to do AP alongside one of the other traditionally expensive hobbies (model engineering) it matters to make my money go as far as possible. That doesn't mean the cheapest possible kit or making silk purses out of sows ears, but it does mean getting the best out of what I have rather than simply upgrading for the sake of it. For example I shelled out on a 130P-DS and coma corrector because the 'return on investment' was significant and also the scope was better suited to my mount. For me it's about spending wisely and not putting people off who don't want to spend a fortune on a hobby they aren't sure will suit them long term. Building on Steve's excellent post above, I think that since the emergence of affordable 14-bit DSLRs (I started with a 210-but D10) followed by other new CMOS sensors it's increasingly possible to get good RGB data at shorter exposures of 30 - 120 seconds, say. These require some form of tracking, but both Alt-Az (fighting field rotation) and unguided light EQ mounts CAN achieve this an give you a good majority of usable subs. A significant proportion of those who got into AP in earlier days haven't had direct experience of this and because they think you need at least 5-10 minute subs for decent results they naturally discount an ALT-AZ or an EQ3 (I note that 'Making Every Photo Count' DOES say you can start with an EQ3!)

Th thing that's frustrating me is that, notwithstanding the issues specific to Alt-Az mounts 90% of that's discussed and shared in here is dominated by the short sub lengths and a 'grab what data you can' mentality. There really seems to be no interest in threads that focus on these issues elsewhere in the forum. Perhaps as an imager with a light , unguided EQ mount I am in a minority of one?

Imaging on a Budget - Imaging using Alt-Az and light EQ mounts using DSLRs, not just for beginners Mounts - overcoming the challenges (individual sub-topics created by users can easily address EQ, Alt-AZ, Barn door etc.) Scopes - achro refractors to budget reflectors (to cover various entry-level scopes, the 130P-DS thread could go here) Accessories - affordable extras to get more out of your imaging time Processing - getting the most from short subs and limited total exposure Help and advice - Ask anything - the one answer you won't get is spend lots of money! Showcase - share your successes

Speaking as an Admin on another site, it's amazing how high feeling run about two things - people going 'off topic' and topic bloat. When you have lots of specialist topics some end up very empty and ignored and it can also confuse people trying to find the best place to post. That's partly why I think a new topic should not be restricted to Alt-Az, but should be wide enough to attract anyone who faces constraints of sub-length (whether because of choice, budget, experience or anything else). A good example is processing; I have some images I think I could get a bit more out of, trouble is when I go back and reprocess my results are worse rather than better 9 times out of 10. Whenever I ask for advice the response is always 'more data' but this is often not possible. In this thread there have been some examples of people with similar amounts of data (say 30 minutes) 'polishing' images with input and aid from others. When we are comparing to 10 hours of data with Ha it's clear we are not going to get those results and the same processing approach might not be best, plus there really isn't anywhere you can get an idea of what can be achieved with such data except some of the posts in the 'imaging with the 130P-DS thread'. I suppose the thing that I personally want is a way to get a bit more criticism and technical advice. If I put up an image it generally either gets likes from people at a similar level of experience to me (I don't share the bad ones) or a suggestion that more data=less noise from more experienced imagers. I particularly would like to get a handle on what balance of detail and noise works best for such images. For example, its possible to make a luminance layer for a faint nebula that brightens it up without noise - but at the expense of detail. I'm sure there is a potential technique that could be developed taht then puts some detail back on top but perhaps it needs other people to try it as well. Sorry to go on, but this is the sort of issue I would raise in a short imaging forum. Looking at the existing Imaging topics they are mostly by SUBJECT rather than technique, except video astronomy, which only has one sub-topic. Perhaps the High level Video Astronomy topic could be renamed IMAGING TECHIQUES and move "tips, tricks etc." and "image processing etc." to that topic, then create sub-topics under that to address our interests and those of others?

HEAR! HEAR!

I think the linking themes is that we are all essentially imaging in RGB at shorter exposures; it sits between video imaging and the extreme short exposure imagers and the 'serious' imagers guiding at 300 seconds up to ages, often as LRGB or narrowband (which again is both quite specialised and needs a lot of technical stuff). A new subject would be aimed at those who, essentially, use rigs that are equally suited to imaging and visual observation and whose priority is exploring the sky by getting 'presentable' images of lots of objects rather than spending many nights on the same target with half an eye on APOD :-)

Can I suggest that what matters is not so much the alt-az mount, but the short subs (up to 1-2 minutes). Those who have a typical unguided EQ mount (like me) are essentially working with the same constraints as you Alt-Az imagers. I reckon that 90%+ of this thread has been interesting to me and has kept my attention more than just about any other - so much so I started a thread for EQ3 imagers that hasn't take off in the same way. But I have felt unable to share my triumphs and tragedies as they are done with an EQ3 mount, despite my 'standard' exposure being 60s. I would strongly support adding a section to the Imaging area for low-tech imaging as this is the realm of those of us (generally) working on relatively limited budgets. It would be a great place to direct beginners who often get the impression their kit isn't suitable for imaging anything other the Moon and the few DSOs you can see with the naked eye. But it isn't a 'beginner' topic, as I am and intend to stick with short-exposure RGB imaging for the foreseeable future.

Shiny! You can dig more colour out of that!

I use a patch of evenly painted wall that is illuminated by diffuse daylight on our landing. To eliminate any bias due to uneven lighting I rotate the telescope taking (usually) three photos in each of 8 or 12 positions.

Well done Yamez, a great first result with nice detail in the core. I think you will be able to reduce the noise significantly by going to ISO800 and stretching the image rather than using ISO3200.

It's a good fit on my 400mm lens and Canon 450D.

Actions are built using existing controls, plug-ins can use methods you can't replicate. So in theory Steve's or Noel's actions can be built by hand, HLVG or Gradient Exterminator probably not.

I usually end up with half a dozen versions of my images. I sometimes put the best into photoshop as layers and adjust their percentages to try and get the best 'mix'. I have a tendency to over-sharpen and over-colour, so taking the over-processed version as a layer on top of a more conservative version and experimenting with the percentage is a good idea.

Core doesn't look bad to me - there are stars in it, unlike mine!

They may have cold welded together if the anodising rubbed off the screw thread.

Four hours of Andromeda is great. Or you cold try the Heart and Soul or Flaming Star.

You might find the graph in this thread interesting, made by looking at dozens of Exifs...

Put in freezer, then briefly warm the outer ring in your hand before quickly trying to separate them.

On the other hand, the low weight of the 130P-DS means it places less of a demand on a mount.

My secondary was badly rotated and the three screws jammed solid until I loosened it. Now its sorted I can collimate without touching the central screw.

I have a home-made laser collimator - the key to success is collimating the collimator, luckily I have a pair of large, matched v-blocks that i can rest the collimator in and rotate it and adjust until the spot rotates but doesn't move.

You'll find that if you twist them the right way the spring opens up and they will slip in or out, wind the other way and it will lock solid. Hold the secondary support NOT the vanes when applying huge force to loosen the phillips screw - its easier if you loosen all the adjustment screws first. My scope (used) was way out and the adjustment screws were over-tightened from trying to correct it without loosening the central screw (I guess). Definitely fussier to set than the 150PL - you would think a longer scope would be harder!