ollypenrice

But perhaps the problem with the older scopes can be the blue correction, which didn't need to be anything like as good at the shortest wavelengths as is now needed for digital cameras? My Mk 1 F5 Genesis (remember that one?) was Tak-like in narrowband but out of its depth in blue. Olly

You'll struggle to find a scope that can do better at F3.9 than that. Top left isn't perfect but it isn't bad and you can write a quick Ps action for 'rounding stars' (one at a time but there won't be many) to fix that corner. Mind you, if you were using an 8300 chip you might not be so happy... While it ought to be possible to buy a scope knowing that it will give perfect stars corner to corner within the specified image circle it just seems that you can't! One thing, though Steve (Kirk!): put the official flattener on your TEC and there you will have a flat field you could land a glider on. WIth full frame ours isn't even slightly taxed. Olly

It's a serious question! I don't think you can get M31 in a single frame with anything resembling a telescopic focal length. If you get the full outer glow it is a two panel in full frame format at 500mm FL. That means you have to have something that will cover full frame to get anywhere near, in one. The claimed image circle for the Esprit 80 with flattener is a rather paltry 33mm so that won't take a big chip. For the big Kodaks you need about 45 or 46. Theory says 44 but that turns out to be a bit 'iffy.' It was after some thought that we went for the older fluorite FSQ106N option here. The 88mm claimed circle rather puts the problem to bed. Buying second hand you can ask for a sample image from the scope, too. It shouldn't be this difficult but it is... Olly

Besides the two Steves on here I have come across several other problem Baby Q posts, all about corner stars. Mine was fine and there's one here in our robotic shed which is also fine but I no longer recommend the Baby Q when asked because there are too many bad ones circulating. When you can't trust the European importer (and you can't, as Steve's experience shows) or the QC then it's time to take a rain check. The clincher in Steve's case came when he found the same camera perfectly satisfactory in a later scope, so it wasn't chip tilt. In an all-screwed assembly that's about that, surely? We now run a pair of old FSQ106Ns here and are 100% happy wth them. Olly

Yes. Sigh of relief! Olly

Would switching from side by side to piggyback be an option? As for concrete, I don't think heat is an issue. We have a six tonne concrete base for our 4-scope remote hosting shed and daytime temperatures reaching the high thirties in summer. I think the effect on seeing is negligible. Likewise in one of our own 'in house' roll offs we imaged at 0.66"PP with a 14 inch deep sky rig and had no issues. Olly

When you cannot be sure of the distance you cannot be sure of the real speed of movement. If your brain has convinced itself that the object is distant then it will be very hard to dislodge that notion and you will therefore greatly overestimate its speed. If you are intentionally out looking at the stars you may well be predisposed to think in terms of long distances. Something much, much closer moving much more slowly would be my guess. A drone seems highly possible. I don't offer this as an explanation but just as an example of how our eyes deceive us. I'm out all night regularly since I run an astronomy guest house and recently I noticed a slowly moving light near to where I would have expected to see Capella. My view was limited by the house and a tree at this point. The light was moving randomly and quite slowly but I was sure it was moving about. I kept my eye on it and moved to more open ground. As I did so the movement diminished and finally stopped altogether and I was simply looking at Capella. Why the impression of movement? I don't know, but the limited field of view and possibly motion in the tree branches had created it. Olly

Nor do I. I host a robotic FSQ85 which did a recent first light and, with an 8300 chip, the corner stars were not perfect, they were elongated radially from the centre a tiny bit. A pixel peeper would have been disgruntled (and in view of the price one can understand that!) but I'm a pragmatic imager and I'd have bought that scope and camera for my own use. It wasn't far from perfect and I think you'd be taking a risk in swapping it for something else in its class. Yours is far worse and I would not accept it. I do think Takahashi have a problem with the Baby Q. As an aside, I now use a couple of old FSQ106N fluorites, mine and Tom's, worth about £2K a pop and they have no trouble at all with full frame sensors. Quite a bit cheaper than a new Baby Q.... Olly

Without doubt. Olly

Just a further comment on two posters above. Pieter was too modest to say that he is an expert mechanical engineer and Steve was too modest to say that he wrote yet another bible, this time on how to live happily with SiTech! Olly

It's the multi rig that really does the business for us. That's the dual Tak. The TEC is a luxury on the side but the multi rig is fast... Now, sure, I personally have lots of clear skies here but the guests who come for just a week have just a week. The tandem is the thing. I counsel... multi-scoping! Olly

Hyperstar. The numbers look great. The pictures are not always that good...

As I said above, I think Takahashi are overly optimistic in the flat field claims they make for the FSQ85. There does seem to variability from instrument to instrument, too. I used mine with a 15mm sqyuare chip and had excellent results but I think Takahshi should be brought to book over their field size claims. This has been much discussed on here. Olly

You cannot ignore the pixel scale when thining about an imaging rig. If your pixel scale is too small for your local seeing and your guiding to support then your long focal length is simply not going to bring in more detail. You will reduce the FOV without increasing the resolution, which is clearly a waste of time. (You might just as well resample a shorter FL image upwards in software.) It might also be worth remembering that, within the backfocus of an SCT, you really need room for an off axis guider. Using a separate guidescope with an SCT is not a good idea. Accurate guiding is not just about round stars. Random errors produce round stars but resolution is still lost. Olly

One of my guests uses a Berelebach wooden tripod for his mobile Mesu. It seems to work superbly but I'm not sure which model it is. https://www.berlebach.de/?bereich=firma&sprache=english His website is here: https://pietervandevelde.smugmug.com/ In terms of quality of construction and performance the Mesu is in an entirely different class to the EQ8. Have you seen this video? (Sorry, the quotation system on the new forum still won't play nicely for me so you'll need to scroll up from here to the top of the thread.) It gives a good insight into the EQ8. At the risk of repeating myself, the Mesu I share with Tom O'Donoghue has still to drop a sub to guiding error of its own. We have dropped a few due to faulty guide camera cables but you can't blame the mount for that. In terms of its fit and finish it looks like new, being made of first class materials throughout. I'm one of the few astrophotographers who can say that his mount is the most reliable bit of kit in his observatory. Olly

Ah, I misread the chip dimensions. My apologies. Olly

27x34mm is pretty big. I wonder if the FSQ85 will give distortion free stars at this size? Both Yves Van den Broek and I found that it was nowhere near covering the 11000 chip without distortion. I know Tak claim it will cover 35mm format but - well - I think it may be a rather wild claim. Are your filters 2 inch mounted or unmounted? We use both in our dual rig. The vignetting is certainly more severe with the mounted set but both are workable on the full frame Kodaks and FSQ106. Olly

For an imager the H beta line traces pretty much the same gasses and structures as the H alpha but with a fraction of the signal. Is it worth it? Why not add a touch of Ha to the blue channel as surrogate H beta? Many do. But for visual hunters of the Horse then our eyes can see H beta and so this filter can pass just enough of the emission to render the dusty HH visible by contrast. Yes well - I reckon I've 'seen' it three times in our 20 inch Dob but I'm using the word 'seen' in a rather optimistic way!! Olly

Ah yes, you'd mentioned the FLO devices but I'd forgotten. It's too hot to think at the moment!!! Olly

That, my dear fellow, is the definitive multiple rig. Even the cables have been persuaded to curve like synchronized swimmers. The style is a tantalizing blend of the military and the surgical. I'm rarely of a religious turn of mind but I do believe I could worship that... How do you get the scopes parallel? Olly

Quite surprizing, really. However, I've seen enough of very fast optics to know that they are not for me. I prefer two slower ones! I'm not asserting anything, here, other than a purely personal preference. Olly

Ours is all about speed. The two Taks are aligned using a Cassady T Gad under one and carried on a Mesu 200 which could easily handle another two... Five hours become ten hours. Or maybe, in terms if residual noise, it's better than that because the noise which calibration fails to remove is partially neutralized when combined. Note that doubling the scopes is only the equivalent of coming down one F stop. However - and here's the key bit - these F5 refractors work. Always. Every single time. They have a workable depth of field. If you go, instead, for a single faster astrograph you have to be ready for what that entails in terms of making it work. Good luck! Olly

It seems as if it's well worth the extra bit. Olly

Totally mad! 'Mad as the sea and wind when both contend which shall be mightier.'