ollypenrice

I think there are just two Steve. Olly

I strongly suspect it's original but, as you say, it should be possible to find an alternative plug. Olly

I've never been unreservedly keen on SCTs. They give large aperture from small volume, make great solar system imaging scopes, are very comfortable to use visually in Alt Az mode and have tended to give me eyepiece views which had the information but not, for me, the engaging thrill of being out in space. Somehow the stars weren't really pinpoint tiny and the backgrounds weren't as dark as I'd have liked. It's hard to explain but this opinion grew while I owned first an 8 inch and then a 10 inch Meade. (It wasn't down to collimation, which is easy to get right on an SCT.) I've been very impressed by the only C11 I've tried, though. Anyway, rightly or wrongly it was was these expectations that I spent my first observng night with the 14 LX200 GPS kindly bequeathed to us by Alan Longstaff. I was in for a very big surprise... GPS and Go To. With the control panel on the south side (not the north as shown in the picture!) you set the tube to horizontal and pointing north, then ask the mount to align automatically. It performs an assortment of gyrations, twists and tilts to orientate itself before heading off to a star named in the handset. The first was Arcturus, which it missed by about 15 degrees. You centre this in the EP and confirm, whereupon it coffee-grinds its way over to a second star, Dubhe this time. It was in the EP. Encouraging. And that's it, you are now supposedly aligned. There is no need to set time, date or location since all come from the GPS. Jupiter was up so we performed a GoTo and the planet was just out of the EP (a 26mm TeleVue Nagler giving 135x.) Not bad but not ideal for a complete beginner had the target been an obscure DSO. 'Going To' Saturn produced the same 'near but not quite' result. However, when we asked it to go to M22 it ground more coffee and, bang, there it was smack in the middle of the EP. And this remarkable precision on DSOs continued throughout the night and all over the sky. All present were mightily impressed. I suppose there is some minor glitch in the planetary ephemeris but it won't be a priority to sort it out since it's easy to find and centre the planets anyway. The views. I was knocked out. Tiny, tiny stars against the darkest of backgrounds. (We were SQM21.6 last night.) The Nagler allows, nay requires, you to move your head to find the field stop. The superb stellar quality was maintained edge to edge. The views were not just informative, they were beautiful. A favourite was M24, the Sagittarius Star Cloud. This was too big for the FOV, naturally, but cruising within it we found clusters within clusters and, notably, some lovely powdery patches of minute stars which I don't recall seeing before. This is the kind of view I love. M51 wasn't perfectly placed but showed spiral structure, 'the bridge of light' and a satisfying scale and brightness at 135x. In fact we just left the 26 Nagler in all night, after quitting the planets. M27 was very dumb-bell shaped, the central star was just visble in averted vision for me and, again, the scale and brightness were very rewarding. There was nothing of the 'fuzzy blob' about it! The FOV is limiting with a 3.5 metre focal length but the sky is not short of targets at this magnification if you have the aperture to support it. This and that. Because we couldn't get the electronic focuser to work we were obliged to use the moving mirror focuser. It was OK, but has the well known backlash. Best to make your final focus a push of the mirror against gravity. Image shift was very slight and there's a mirror lock available. We have the electronic focuser which seems to be a motorized Crayford, but its cable collides with the fork mount! (I've been seeking advice on this on another thread.) An alternative focusing socket on the fork higher up, and not mentioned in the manual, doesn't work. One way or another we'll sort this out. Grinding coffee. The scope is loud when on the move. We don't have neighbours nearby and Alan was two miles from the next house in Shropshire, but if you observe from an overlooked suburban garden the noise might very easily be an issue. Stability. The tube is held stiffly in altitude but has quite a lot of elasticity in azimuth. This seems to have diminshed since we began running the scope a few nights ago and is not an issue for observing. I wouldn't want to try DS imaging without much more stiffness in the RA drive, but we have no DS imaging plans for this instrument. We want to let it do what it's good at. Conclusion. Because this scope was Alan's and was a gift from him I really wanted to like it. Happily, I do like it. In fact love it and can't wait to get out there with a long shopping list of targets. The views are just what I want telescope views to be and the excellent GoTo makes for an enjoyable evening's observing. A beginner can sit down at the scope with a list of objects and set off with no need of help from anyone else. OK, the FL is long and somewhat restricive but the aperture compensates for that by supporting high magnification. With a Telrad on top (not seen in the picture) a beginner can see where the scope is pointing and pick up a pair of binoculars to take a different kind of look at the same part of the sky. That scruffy roll off in the background has now been re-clad in respectable marine ply and is awaiting a brass plaque identifying the scope simply as The Alan Longstaff Telescope. Olly PS The Wild Duck Cluster was Alan's favourite and it really was lovely in his scope. Its improbably geometric shape was shown to advantage by the smallness and brightness of its stars. I always think it looks like a distant space station. Wonderful. Roll on the coming of night.

It does show every sign of being original. The other end goes directly into the focuser unit and doesn't seem to have been touched. The presence of the extra focuser socket on the tines, and not mentioned in the manual, suggests that they had a problem. Not to worry, it can be fixed one way or another. The error is reprehensible but I must say that, after using the scope last night, I am thrilled to bits with it. I've had 8 and 10 inch Meade SCTs before. The 8 inch was 'okay,' the 10 better, but while the 10 pulled in the light you'd expect it to and the images were full of information, they lacked that emotional buzz which comes from tiny, pinpoint stars and a dark background. The 14 inch, however, really did deliver. It was a thrill to use and greatly, very greatly, surpassed my expectation. I'll review it in the appropriate part of the forum. Olly

Now that's not daft!!!! To be continued.... Thanks, Olly

Many thanks, Davey. Yup, what's changed is that the fork tine has more metal and the clearance is gone. Looks like the silly so-and-so's didn't think it through and added the alternative socket up on the tine as an afterthought. I've just had a look inside at the second socket but there are no obvious loose wires. I'm wondering if you are supposed to configure your choice of socket in some way. At least I can see why there's a problem. Cheers, Olly

I'm setting up a 14 inch LX200 which came with Meade's microfocuser controlled via the handset. It works, but there's a problem. The focuser plugs into the control panel using a right angle plug which seems to be original. Trouble is, as the fork swings round in azimuth it collides with this plug which simply sticks out too far. It's fully inserted, though. I can see no way that the standard plug could ever clear the fork. There is another socket marked 'Focuser' on the inside of one fork tine but, when I use it, the focuser doesn't work. This extra socket gets no mention in the manual. I have to wonder if Meade slipped up when they beefed up the 14 inch fork, as I believe they did, and created this problem. Can anyone advise? Thanks, Olly

By 'actual colour' you mean 'perceived colour,' I guess. If, by 'actual colour' you meant the light sent out by the object, then the huge gaps in the RGGB passbands mean that you would really get vastly more information out of a filter set without gaps. No? I think that, since the OP asked about mono or colour, we should not turn it into DSLR or CCD. That's for another thread. Olly

It is an advantage that your tracking is not perfect when doing fast frame camera imaging. It means that different parts of the target land on different pixels each time, so noise from the chip is averaged out while signal from the target builds up when you stack. Take one bad pixel on your chip. It finds itself in a different part of the image each time so its damage is averaged out to almost nothing. This is possible because the stacking software reads each image and aligns them to one you have chosen as a good one. It is the equivalent of guiding after the video has been shot. Individual fast frames are too short to be affected by blurring due to the mount's errors. But if you want to expose for ten minutes or thirty minutes then you need a guider to keep the mount on target throughout. Olly

I'd agree with this if you didn't have to do so many work arounds to make DSLRs function for astronomy, for which they were not intended. I use Atik cameras and the user-friendly default software called Artemis Capture. It is designed for astronomy. It just plonks everything you need on one screen in front of you and off you go. You can, in luminance, pretty well guarantee that in a 5 second sub (maybe binned 2X2 or 3X3) you'll be able to see you target easily and frame it as you wish. You have a full width half max focus tool. You have cooling to control noise. In short you have the right tool for the job. I think DSLR astrophotography is obscure and confusing... Olly PS While working as a motorcycle instructor I once had a young lad turn up so I gave my usual introduction and then set him off for a gentle potter around the training circuit. He let the clutch in nicely enough but always keeled over shortly afterwards. I was stuck for a solution till it occurred to me to ask if he could ride a bike. He couldn't. Aha! After that I always made a point of asking but this had never come up once in my own instructor training.

I can't see why mono would be significantly harder. You just shoot through a red filter, then a green, then a blue, giving each image a name to identify the colour. Processing goes like this (in AstroArt for me.) Stack the reds, the greens and the blues to make three images called Red, Green and Blue. Go to Images, Align All, set to Translation and Rotation and click once. Go to Colour, Trichromy, and put the red in the red box, the green in the green and the blue in the blue. Check Auto White Balance and click once. You now have an RGB image. At this point you will be in the same place as you would be with an OSC. Both will have gradients which need processing out. I often think that only people who haven't tried mono imaging think that it's difficult! I just don't think it is, though. Olly

I no longer have an OSC. When I did have mono and OSC versions of the Atik 4000 I did a direct shoot out and article for Astronomy Now. There was precious little difference between the final images but I was imaging M42, a bright target and one not needing Ha. The longer I kept the OSC the more frustrating I found it on faint targets. Tidal tails and extensions in galaxies just took forever and, in the end, I went to dual mono cameras. Unlike Tim I never found OSC easier to process. Rather the reverse, in fact. But there are any number of reasons for this. I still think the double green is an issue for OSC in astronomy. However, Tim's point about 'getting something keepable' is a good one and is, as I said earlier, the real reason for using OSC if that's what you fancy. My real beef is with the speed claim. Olly

Ronin, you trot out this answer every time anyone asks this question and, alas, I don't agree with much of it. Please give some thought to the following points. 1) Mono is more expensive, agreed. 2) The increase in resolution by using all the pixels in a mono is actually trivial. The debayering routines are very sophisticated and interpolate (make an educated guess) about the 'missing' information remarkably well. I advocate mono but not for reasons of resolution because I have found very little or no gain in resolution when using mono over OSC on the same make of chip in the same telescope. 3) You do not need more time with a mono camera, you need less. An OSC camera shoots through colour filters all of the time so it can never capture more than a third of the incident light, ever, under any circumstances. However, when a mono camera is working in its luminance mode it is capturing all of the incident light and obtaining a massive speed advantage over colour. This cannot be less than a 6 to 4 time advantage and can easily rise to being twice as fast. The LRGB system was invented to save time. 4) OSC cameras are filtered for daylight and have twice as many green filters as red and blue. This is entirely inappropriate for astrophotography and wastes more time. 5) OSC cameras use low grade absorption colour filters rather than high quality interferometric ones availble to mono imagers. 6) Mono cameras can capture narrowband efficiently, Ha opening up many nights of moonlight to the imager. A while back I set myself the task of demonstrating the remarkable speed of the mono camera by doing a two hour Heart Nebula. This has just an hour of Ha and twenty minutes each of R, G and B. This was at a FL of 530mm and at F5. I do not believe I could have obtained this result, or anything remotely like it, from an OSC camera in the same telescope in two hours. At some point I'll do a fast LRGB image as well to make the same point. It's been argued that using colour filters adds to the complexity because you may have to refocus between colours. The other way to look at it is that non-parfocality does not come from the filters but from the optics, so at least you can refocus a mono but with an OSC some of your colour will always be out of focus. The genuine reason for going for OSC is that it may be less frustrating in terms of capturing an incomplete data set. But mono is faster. It really is. Olly

You won't need the flattener for the small chip but the colour correction is better with it. On most targets I don't think this will matter. Olly

Assuming Steve's using the TEC flattener the FL of the TEC will be more like 1015mm. It's also worth noting that the TEC flattener almost certainly improves the colour correction in the blue for CCD imaging. I'm convinced mine does, having imaged with and without it, and there was a CN discussion suggesting the same. It was OK without it but there was sometimes some blue bloat on bright hot stars. I'm also enjoying 0.9 "PP with my TEC/460 combination. It seems like a sweet spot and is getting me into the galaxies. On the Moravian/QSI decision I'd be very surprised if you noticed any difference in use. Olly

I don't know, Gorann, but our pair of Tak 106 FSQs produce just two of these dark shadows per bright star, 180 degrees apart. I call them the 'inverse lighthouse beams.' They don't bother me. On anouther forum Prof Greg Parker assured me they arose from slight optical pinching. I had always thought of pinching as producing triangular stars but Greg was confident. Olly

Such artefacts don't normally bother me, but here's one that does. Ignore the image quality, it's just a crop from a test stretch, but the artefact in question is the double spike only in red. In this example the one at about ten o'clock is faint. The one at five o'clock is more obvious. Sometimes they appear as really very bright and thin red lines either side of the star. They arise only in the TEC140 using a camera and filterwheel which does not produce them in the Takahashis. Indeed this example is from a new Atik 460 with different filters, so the effect must be produced by the scope. The lines are always and only in red. They don't afflict all stars by any means, or I'd be a lot more disgruntled. They few that they do affect I fix in Ps. Any ideas? Olly

Not an engineer by profession but I don't use guide rings either, for the reasons you imply. I use fixed tube rings, bolted down hard. Olly

Hmmm, spring loaded guidescope? Not for me. Didn't they make a version without the spring? Olly

When using the Skywatcher finderscope as a guider, what do you do about the single spring loaded 'finger' which works in opposition to the two nylon alignment screws? This is a nifty arrangement for making a finder easy to align but it's the last thing you want on a guidescope, which needs to be rigidly mounted to avoid differential flexure. Olly

Bobro's earlier post explaining the relationship between pixel scale at the imager and pixel scale at the guider will answer your question. Focal length is just a shorthand way of discussing the matter. What I don't think has come up is the matter of flexure, particularly when imaging with reflectors. It is very hard indeed to remove all possibility of primary mirror movement in a reflector because if the mirror is held too tightly it will experience distortion. If the mirror moves slightly, so does the image. A separate guide scope cannot 'know' this so cannot correct for it. However, an Off Axis Guider uses the same light cone as the imager for guiding, so mirror movement (known as mirror flop, though this is an exaggeration!) will be seen and corrected by the guider. Under no circumstances would I guide a catadioptric with a guide scope. I've always used an OAG for this. The small mirror of the 150PDS might let you get away with it but, in principle, reflectors are best guided via OAG. You need to be sure that you have enough backfocus for an OAG, though. It pushes the camera further down the light cone. Olly PS You don't need to calculate pixel scale yourself. Here's the easy way to find it! http://www.12dstring.me.uk/fovcalc.php

It was a while before the penny dropped with me, too. Olly

That's true. The other reason is that it makes the image more repeatable if you want to come back to it for more data in the future. It takes ages to recover an arbitrary camera angle when framing. And then there are mosaics. I once tried to do a mosaic with an arbitrary angle optimized to the target. Never again!!! Olly

Dead easy, Steve. Have the camera running on a bright star. Open the crosshairs on your capture screen and put the star in the middle. Now slew slowly on whatever is the long side of the chip (which could be RA or Dec depending on Landscape/Portrait orientation.) Unless you're already orthogonal the star will now be above or below the line of the crosshair so you rotate the camera so that the star is back on the the line. Now 'slide' the star along the crosshair by slewing the other way to the opposite side to confirm it's remaining on the crosshair. Give the camera a final tweak of rotation if necessary. It takes two minutes at most. Olly Oops, beaten to it! As Freddies says, you can't have both optimal framing and orthogonal alignment but I find I hardly ever need to move from orthogonality.

Yes. But, thank God, Monique hasn't... lly PS, Seriously, filters really do start to get expensive in large sizes. The absolute killers are the square ones for the 36X36 chips. If you decide to look (and I wouldn't!) do so while sitting down.