Nikodemuzz

Thanks KP82! The plan is to have an observatory at some point, but it will take a while still. Now I'll have to settle for storing the scope in the cool but not quite ambient garage. I can usually set up well in advance in the backyard, but cool down times can become an issue anyway. My thinking with getting the TOA-130 was that a reasonably priced used scope can be sold again for minimal losses in the case it's not a good fit for my use case. And if it is, I'll be set for life. I can already tell that handling wise I worried too much about the weight. The scope is not light by any means, but is really not a problem at all. Here are a few more pics:

The long considerations, comparisons and introspective use case studies have finally come to a close as the courier delivered this today.

That is a good question, really. I had dismissed the FSQ because of its new price. The image size is not that different to the reduced TSA-120 (530mm vs 630mm). The visual use is a question for me even with the extender, but I have to be honest here. I enjoy visual observation, but I really don't enjoy prolonged stays in the cold. So imaging will be the dominant use case for sure. I dream of some day living in a warmer climate where I would be able observe more comfortably, but who knows when that will happen if ever? The FSQ would really probably be a very sensible choice for me. And here I was, finally arriving to a decision on the TSA. I really must seem hopeless, like a plastic bag in the wind! 😅 I did consider the APM LZOS as well, by the way. Other options seemed more tempting to me, and APM never sent me a quotation so they were chalked off the list.

This is true. Although with the reducer it will be F5.25 or thereabouts, but still. I have chosen to go that route because I wish that the scope would serve well as a visual instrument, too. However, there is an FSQ-106 in the Sales section at the moment that is making me question this approach... May I ask what was your pick in the end?

I already have the short end covered with the SpaceCat. Now I'm looking to get a bit closer to the targets that are a too small for the Cat. 600-700mm has been my target, which the TSA/TOA fits nicely when reduced.

Exactly, I have read similar comments. And given that the light gathering difference is only about 15%, I wouldn't expect there to be a significant difference. Which further underscores my comment about the factors favoring the TSA-120 seem heavier.

I have (again) moved on from the Esprit 150. There were enough reports of pinching (perhaps slight but still) from local colleagues, and the vendor also said it would be somewhat likely to happen in our temperatures. Now it seems like a two horse race between a new TSA-120 and a used TOA-130F. With the more expensive one being used the prices come very close to each other. I'm very tempted by the TOA, but I think I'm suffering slightly from the illusion of the "good deal". Factors favoring TOA-130F: Presumably better optics, at least by reputation (albeit slightly) 10mm more aperture, better choice for shared visual and imaging use as a "keeper for life" Good price for a used item in good condition Factors favoring TSA-120: Low buyers risk for a new item with guarantee Option of a Feathertouch focuser Half the weight Faster cooldown To me it seems as though the things I listed for TSA-120 seem like more concrete and "actionable" benefits than the ones on the TOA side. Did I forget something important?

Yes, makes sense! Well explained, thank you. I don't think your math quite checks out (1,25^2=2,5), but I get the point nonetheless. The benefit is there, but it might be a bit smaller. Binning is something I knew I was giving up using the OSC camera, and those compromises were calculated ones. Mono imaging might very well be in my future, but at the moment I'm very happy gathering experience with OSC. During processing I have already noticed things that would be easier and better if I had mono data, and one can't argue against the shortcomings that the Bayer matrix brings. Should I go mono, I would like to get high quality filters and fully automated equipment to take the fuss out of the experience. That investment will have to wait a while still. The sampling rate was something I hadn't paid enough attention to prior to starting this thread. My thinking has changed as a result, meaning that I now think going in with a reducer is the correct choice. Flattener, perhaps unnecessary. 😃

Thanks for the thorough answer, @vlaiv I would be using a field flattener anyway, at least I think you need one already with APS-C sized sensors. The question then is, without reducing, with reducing, or both? I would argue that at least I don't need both because the FOV difference is quite small. About the speed, I understand what you mean by more of the light from the target hitting single pixels. A drastic example of that would be that the subject is only the size of a single pixel, meaning that all of the light hits that single pixel. I guess my point is, how much does the SNR increase, and is it enough to account for the loss of resolution? I'm sure the F-stop rule doesn't apply here anymore (meaning that one F-stop equals double the light or half the exposure time). That's a good point about the reducing factor and the original illuminating circle of the scope, I didn't know that! I'm sure you are also correct about the sampling rate. Taking that into account, would you say that with those sampling rates it would be better to image with the TSA-120 reduced, even smaller targets? Because the additional resolution wouldn't materialize anyway due to oversampling.

Yeah, it is pretty scary to go near these precision instruments with your own toolset. I wouldn't have had the confidence without clear instructions. I want to say that it's just a few bolts, follow the instructions and you'll be fine. But in the end only you can determine if you want to do it. 😃 It could save you the trouble of sending the whole unit for maintenance. On the other hand I'm not sure how easy it is to get spare parts from Celestron.

Continuing a little bit, the easiest way to assess the damage would probably be to head into Chapter 3 in the guide (the RA axis strip down), and there skip to the stage where there are the instructions for removing the worm carrier. If I remember correctly, removing the carrier is a simple job, and let's you see in what state the RA gears are. Edit. You would start from the point where it says "Loosen the upper RA worm carrier set screw."

Ouch, sorry to hear about your mishap! I can very easily imagine that happening to myself. Also, welcome to the forum! From your description it sounds that some of the gears have been damaged. That doesn't necessarily mean that the whole unit is a write off. If you feel up to the task and have some tools lying around, you could follow this guide and disassemble the mount enough to see what has been broken: http://www.astro-baby.com/EQ6 rebuild guide/EQ6 Strip Down Home.htm It is for the EQ6, but the CGEM is essentially the same. I followed the same guide when I tuned and relubricated my CGEM. I believe there is also an RA limit function in the CGEM handset, were you can set how far east or west the mount is allowed to move. I know this doesn't help fix your current problem, but might prevent it from happening again.

Hello all! I have been looking for a refractor in the ~1000mm FL class for some time now (there is a separate thread on the subject). I have sort of taken as a given that I will get a reducer to match the scope. The main benefits that I have thought the reducer would give me are: - 1. Increased field of view, in other words possibility to image more targets. -2. Faster imaging, taking the scope from F7-F8 to F5-F6 territory. I have started to doubt if there is any real benefit for me on either of these points. Let's address point 1 first. The only other scope I have at the moment (and for the foreseeable future) is the WO SpaceCat. Combined with the APS-C sized chip of my ASI071, I can cover most wide field targets in the sky. When you visualize the fields of view of these options, it becomes quite clear how small difference in FOV the reducer actually makes. In this example the larger refractor is the TSA-120, but the case is similar for others in its class. For those that use a 0,8 reducer instead of a 0,7 the difference is smaller still. There are a precious few targets that are just the size to fit between the yellow and red rectangles. To address point 2: Yes the F number decreases. However, if I'm imaging the same target it doesn't make my data collection any faster, I just get more space around it. For smaller targets I would actually lose resolution. Right? So it makes no appreciable difference to imaging at native focal length (with a flattener of course). Nothing becomes any "faster". Am I missing something? It seems to me that I would get a much larger impact in FOVs by getting a camera with a smaller sensor compared to a reducer. Sampling rates are within acceptable limits on all options for the TSA120. The SpaceCat is its own animal with the short focal length, with that scope I'm undersampling either way. 1,10 "/pixel ASI071 + TSA120 1,57 "/pixel ASI071 + TSA120 + reducer 0,86 "/pixel AS533 + TSA120 Granted, getting a camera is a rather expensive move, but compared to a Tak reducer and adapters, it's not that far off. For most other brands, yes, money lost. 😃 But, I could very well go a season or two with the camera I have now, and get another one from the used market when a good deal emerges. By doing that I could shave a little bit off the telescope investment (in Tak's case, not even that little), and keep things nice and simple with less adapters and bits and bobs to fool around with. Any thoughts? Am I approaching this somehow backwards?

That's interesting! Is there a lot of industry or traffic in your area?

In my experience, yes and no. Or, it depends. Sometimes when it is really cold, the lower atmosphere sits very still, contributing to good seeing. It doesn't do much to jet streams, though. Another thing is transparency. At least in our neck of the woods, it is not at all uncommon to have the air filled with small ice crystals when it is cold. They scatter light, making the sky seem a bit foggy and sometimes rendering spectacular halos. Streetlights might shoot up to the sky as long beams. Here is an image (not mine) of the phenomenon: Yet another phenomenon that might hurt the views during cold weather is the possibility for atmospheric inversion, when the air close to the ground is actually colder than the air layer above. When that happens, all the fog, smoke from chimneys etc that usually rises to the sky, is trapped to the lower air layers. Locally that might wreck your views. Climb the hill and you might be fine!

Good question. Didn't find an answer with a quick glance with Google.

They are, especially in the northern parts of the country. Where I live (in the middle) we see them only occasionally. They are a pretty sight to see, but for astrophotos they are a nuisance!

While having discussions with different scope providers, I have started to think again about the Esprit 150. Essentially, going back a full circle. Being used to mounting the C11, I don't really have experience in handling bigger refractors. Seeing this video was a bit of a revelation: Silly me, I didn't know you could use the rings like that. 🤓 Anyhow, seeing that I'm pretty confident that I wouldn't have too much trouble handling an Esprit 150. I believe the CEM60 should also be able to carry it, although it is on the heavier side of its capabilities. The question would then be the same that has been the topic of discussion lately, thermal performance. Assuming no defects on the scope build or design, the pinching behaviour should be similar to others, or no? I would assume that it would be the slowest one to cool from the models that have been in the discussion. If the scope is too slow to cool I might never get the best out of it, in which case it is the wrong model for me.

Yeah, no choice if astronomy is your thing here, I'm afraid. 😅

Markus stated that they guarantee their scopes perform until -30C, below which one can expect pinching. Although there are nights when the temperatures do fall below that (just the other night), the vast majority of situations would be OK in that respect. In that sense I would be fine with that.

It is always great to hear your experiences! I think you are right, a vendor more or less has to say something to that effect. I know from my own profession how easily customers take your words as promises and guarantees even though they might have been just educated guesses, so one must err on the safe side. The CEM60 should be able to handle the TSA allright, I think.

There is a lot of truth in your post. It is easy to get sucked into the vortex of comparing, reading reviews and discussions and contemplating things that are essentially minor details. All the while talking yourself into getting products that you want, rather than what you need. Or what would match one's skill level. Reading this thread from the beginning you can observe how my own targets and budget drift. I'm quite aware of this, and have read my earlier posts just to remind myself of it. 😃 In terms of value, you are probably very correct, and I would think that the Pareto principle applies here as well. Meaning that one can probably get 80% of the performance of the high end scopes with 20% of the cost. That 80% would possibly be enough quality that it would never become a limitation in my astronomy hobby. And yet, accepting all of this, I'm still considering owning one of the high end units. To be in a position to even consider such an investment, or investment in a hobby of any sort during these times means that one is indeed fortunate, and in a privileged position compared to many others. I think that for many people who are lucky enough to have a steady job despite the pandemic, things have changed quite a bit. Suddenly you might have a lot of free time in the evenings. There are no costs related to hobbies, travel, eating out, or basically anything besides the basics, which means that you might actually have a bit more disposable income than before. One can observe this from the comments of the astro gear vendors. I believe FLO is breaking sales records, and some of the scope vendors have described an "avalanche of new orders" during past months. The fact that nobody has stock isn't only because there has been production disruptions, it's also because people are buying a lot of new stuff. It is a bit absurd all things considering, and on the other hand very understandable.

I would expect the Russians to know how to deal with the cold. If anything, their winters are even harsher than ours (depending quite a bit on location to be fair). I'll ask from APM about this.

Sorry to see you didn't get much of a response to your problem! I can't offer any clues either, but would like to ask if you have been able to sort out the reflections? I'm considering the CFF as well and the question of suitable reducers is an important one.

There is discussion about the temperatures earlier in this thread, but let's just say it is a concern with oil spaced scopes. Catalin from CFF actually wrote me that any lens employing FPL53, 55 or fluorite should be considered a risk in these temperatures. I asked some follow up questions but he hasn't had the chance to reply yet. Since I'm not exactly ready to accept that I need to forgo refractors altogether, I accept that I need to take precautions regardless of the design. The LZOS is a good shout, and it is on my "list" (well of course it is an Excel spreadsheet!). I'm pretty sure I haven't seen any negative reviews either, quite on the contrary. Originally I had put it aside due to price, but now perhaps the only thing might be that the focal length is a bit shorter natively, meaning that it has slightly less reach for smaller targets. On the other hand, it makes shooting at native focal length more viable as the system is faster. One could always get a camera with a smaller sensor to go after the galaxies... In that sense there aren't many arguments as to why it wouldn't be a contender now that I think about it again. As you said, the price is pretty much the same as the CFF, and about 500€ more than the Tak. I'll have to ask for availability. Seems like I still haven't quite thought this through, have I?!