Adam J

Take a look at the ASI294mm pro its new on the market this month. Adam

You may need to adjust the gear mesh, a PHD guiding graph would be very helpful to diagnose this. The last image you posted looks like something is binding. Could be anything from cable drag, to a cluch problem, to backlash, binding gears. Everything can be adjusted mind you. Adam

I think that the mass market optics manufacturers are closing the gap as others have said. But in the end many scope makers will only guarantee diffraction limited optics and they define that as 0.8 strehl, the thing is that it should also be defined as <0.25 wave peak to valley in addition to <0.8 and some miss out on that second bit, so you get poor scopes even if they are 0.95 strehl as the portion of the light that is not going to the right place is a long way out causing odd halos when imaging. On the whole diffraction limited is not that great a claim these days as it was back in the 1980's or even 90's modern polishing machines are pritty good, so it should be possible to exceed diffraction limited performance consistantly and by some margin. Worth remembering that every single scope from any optics maker has passed through a interferometre at some point, so the shocking thing to me is not what some of these makes are acheiving on average in terms of quality its that they are still letting scopes that are simply not good enough through to the customer however rare that might be. This is a great video on the process. The difference is the amount of time that is spent getting the best out of the optic, changing spacing, rotating the elements, polishing out flaws. By compairson the mass marked brands will not optimise the optic further once it has passed that minimum specification even if more could be extracted from it. https://www.youtube.com/watch?v=xKIPFWVxvNc So i do believe that you are going to have a better optic from those companies listed above....or more to the point less likely to have a total lemon. But even at that point I have heard of coating issues on some high end scopes (the bit that they all out source). So I guess I would be no less nervious buying an AP scope than a SW scope because although its vastly less likely an AP will be anything but perfect thats balanced against the price I would be paying for it. What I dont beleive is that an APM with a Sharpstar optic in it is any better than a TS or Altair scope with a sharp star optic in it, especially without an optical report being provided. You have got to remember that the optical report is always generated by the maker. If they are not giving you an optical report its not because they dont have one, its bacause they dont want you to see it. They dont want you to know that some of there scopes have much better optics than others, because after all everyone is paying the same price. I guess the point overall is that if you buy a astronomy camera then you can be prittt sure that the one you buy will be almost exactly like the one reviewed in Sky at Night or Astronomy now. That is not the case with telescope optics, some will be better than others. So the reputation of the optics maker is more important than the telescope brand when the two are not the same. Adam

You need a fan with a magnetic breaing / low noise as if its making lots of noise then its certainly causing vibrations to the sensor. Adam

Dont run without the fan, you might be able to reduce fan RPM if you also reduce the voltage to the peltier. When I did this I actually used a water block and trickled water through it. Adam

You dont really need to go sub zero and it will solve a few issues if you dont. Adam

Yes at no stage have I been tempted to try this with my Esprit. There are good reasons why most reducers don't go lower than 0.8x or everyone would be selling them.

The super odd thing about it is that it has not been discontinued yet. https://www.firstlightoptics.com/atik-cameras/atik-11000-mono.html Adam

I considered it but I decided that the weight of a 30mm guide scope was not going to kill it and off axis guiders can be fiddly too. Finally because i am a perfectionist (its really not that bad) I decided to add a tilt adaptor and so i would struggle to fit it between that and the auto focuser. Adam

The only thing I don't get with TAK scopes is why they cant include a 10:1 fine focus. Adam

No that is the mount and adjustment for the linear bearing don't remove any screws or you will have tiny ball bearings everywhere at worst and miss align the focuser at best. Either one is a pain to fix.

The 107mm f6.5 in Coco's link is certainly a rebranded sharp star lens not an LZOS. They do a very similar in appearance 105mm F6.2 that is LZOS. To my knowledge there has never been a 107mm LZOS sold by APM. The quality of the LZOS lens cells are not in question as you say. I would have one if I could afford it. I flagged up the APM / Sharp Star lens as it's the same OEM as the TS branded scope OP is discussing. My only point is that it is dangerous to make a judgement from a single sample good or bad. Hence I wanted to provide a counterweight to Coco's experience with that scope. APM discontinued the 107mm as recently as July this year.

Yes its bad and you need to insulate your heat pipe and the electrically insulate the back of the sensor pcb, people use glue from a hot glue gun sometimes.

One shot colour, and its because you can still take a colour image with a mono camera in three seperate exposures. Adam

No its just that a OSC CMOS astronomy camera has now in 2020 exceeded the performnace of the 10-15yo?? sensor mono sensor in Olly's Atik11000mono. I would love to see what Olly could do with a ASI6200mm pro. Adam

Thats the real question isnt it? My feeling is that the performance gap will be just as wide as it is for any other camera, i.e. no matter how good that image is Olly it would have been even better if you had used a mono verion of the same sensor, or would have gone just as deep in less time. Adam

No, my signature is out of date I no longer own a 130PDS, I have a couple of scopes now but I mainly use a Esprit 100 that I would call average. Its my second Esprit 100, the first was not up to expectations and I returned it, had pinched optics and a clear central zone. But for the record the 130pds had exceptional optics when we'll collimated. It's the mechanicals that let that scope down. Adam

See my edit / link above, I have not had chance to compare them no, i doubt many will had done. I have looked through the doublet but not the triplet, the rest of my comments are a technical assessment based on my general experience with optics. Looking at the moon I only saw the slightest CA with the doublet, it was not intrusive. It was not my scope mind you it was someone at the local club when i first started out. I remember it though as i was considering the same choice before i decided to save for my Esprit 100, and even for imaging I concluded I would go with the doublet. Looking at images online I would say that both have CA (always more apparent in imaging) but I don't really see much difference between images from the two. Adam

Both will have some CA in imaging and very little visually, but if it was me I would be going with the FPL-53 / lanthanum Doublet for imaging and even more so for pure visual. Cools down faster, optically simpler and so you are likely to get a better sample and the ES focuser is not the best anyway. Bottom line for me is that cheaper triplets can be trouble and in that price bracket would I like my chances better with a quality doublet than a cheap triplet. This chap has lots of example shots from the TS 102mm FLP-53 doublet in his profile on telescopious: https://telescopius.com/profile/cvbadengoth https://telescopius.com/pictures/view/33985/deep_sky/by-cvbadengoth He also has a couple of youtube vids on the scope with a good review but in german, subs work ok though. Adam

I have learnt that you pay your money you take your chances with any make after some recent experiences, even the likes of APM. I have seen an APM 107 F6.5 that performed badly (trefoil). Glad yours worked well though. Adam

Honestly, I am not 100% sure warm up is a big issue with CMOS as the number of times I have disconnected the camera by mistake (equivalent to pulling the power) is not insignificant. So while i would not do it as a matter of course I dont view its a critical either. Adam

You cant really see OD on the scale tha the filter response curve is presented on. Also optical dencity has nothing to do with the amount of light that passes at peak transmission, its to do with the amount that is blocked out of band where in effect the line is not quite going to zero. Some of the poorer NB filters only have OD2 hence only block 99% of out of band light. The better filters are OD4 and block 99.99% of out of band light. The difference between the two intergrated across 350 - 700nm can have quite a significant effect on the image contrast. 1% of a full moon lit sky is still quite a bit of light. Edit: I see you corrected this later in the thread, serves me right for not reading ot the bottom. If you want an example of poor optical dencity then Optolong is or at last was one of the worst by this measure. Adam

I dont want him to worry I just want him to be informed and was very careful to say that you will almost always see some SA. I chose to say this on the basis that if the OP is performing a star test he probably has some sort of technical interest in it. Indeed I usually find people are either doing it out of technical interest or because they already suspect something is not right with the scope and want confirmation. However, I will expand on what I said further. OP: Dont worry about Spherical Aberation (SA), star testing is very sensitive and so even very very good optics will still produce slightly less defined rings on one side of focus in comparision to the other, judging the degree of any aberation from a star test requires experiance and something to referance what you are seeing against. It was only my hope that you are better informed about what you are seeing and why it is not unexpected. If it was me that knowledge would make me worry less not more. If you are inexperianced in star testing then the main things you are looking for are: 1) Are your rings round and complete, not Oval or triangular. (Astigmatisum / Pinching) 2) Are your rings concentric. (Collimation) I own a copy if this book: https://www.firstlightoptics.com/books/star-testing-astronomical-telescopes-a-manual-for-optical-evaluation-and-adjustment-second-edition-book.html and highly recommend you get a copy if you are interested in star testing your scopes, along side making / purcasing an artifitial star, its very technical mind you so you will need to be so minded or it may send you to sleep lol. From what you are saying your scope is performing well. So please dont worry. Adam

Better definition to the rings on one side than the other would indicate spherical aberation (under / over correction). But the test is very sesitive so you will almost always see some SA.

You need a really bright star and a high power eyepeice or the rings will appear too small to make out forcing you further out of focus where they star blending together. You need to be at about 200x mag...which maybe you where having been viewing planets. Did you use a filter? Green is normally a good idea. Poorly defined rings can be a sign of Spherical Aberation or just poor seeing, poorly cooled scope etc. Adam