vlaiv

you can, but it is better to have Eq type mount with some sort of motor drive to track the target - much better observing that way as you don't have to constantly nudge the scope to stay on target and you can concentrate on observing.

Why? Just get regular OTA version of this scope and mount separately if it bothers you that there are no collimation screws. Mak102 will be better for planets than 90mm refractor. https://www.firstlightoptics.com/maksutov/skywatcher-skymax-102-ota.html + what ever mount you want to put it on. I know this is more expensive option than bundled version, but if you want option to collimate the scope - it's worth it.

Not add at all - there has been much talk about it and while some have had experience with such scopes and found them without much of a fault (hint @Lockie) I personally went for Mak102 with collimation screws - OTA version is regular and only bundled versions - star quest, one with AZ-EQ avant and AzGti come without collimation screws. I think it is weight saving back cell redesign and personally don't really like it, but like I said, people that actually had experience with said scopes found that they work quite well and are in good collimation when received and don't go out of collimation in use.

I would not consider using filter drawer or wheel with OSC camera unless you have permanent setup. I don't see much point in changing filter mid session with OSC camera? In any case, 1.25" filters have something like 28mm of clear aperture, while 294mc has diagonal of about 23mm. No vignetting is going to occur if you mount filter relatively close to sensor, and if you don't have filter wheel/drawer, you can mount filter very close to sensor, so vignetting would not be my concern. Here is flat with 1.25" filter on my ASI1600 - which is very similar in size. Scope is also very fast - F/6 reduced by x0.79, filter sits in filter drawer: Image is stretched to full range 0-1. Same flat stretched to 82% - which is caused by slight OAG shadow in bottom part. Vignetting in the corners is about 92%, but I'm not sure if it's down to filters or general vignetting from the scope and reducer. Purchase filters based on future usage. If you plan for larger sensors, switching to mono where you'll use filter wheel, etc ... and you have budget for it - go for 2" filters. If not, there are filters in between like 36mm unmounted filters that you can consider and will cover up to APS-C sized chip.

You don't need to bin your data if I'm reading things correctly - you are using F/12.4 with ASI1600, right? Optimum sampling rate in Ha for 3.8um size pixels is F/11.58 - which is close enough to F/12.4 as is and no binning is needed. In above case, binning was needed because quark was used with x4.2 integrated barlow and camera with 2.9um pixel size. One would simply load SER files from fire capture - light SER, dark SER, flat SER, flat dark SER into PIPP, under input options select bin x3 and other options as wanted and as output - again SER/16bit, or possibly 32bit fits which would then be loaded in AS!3 for stacking. That would be the way to get binned data for those that need it to get closer to optimum sampling rate.

I will need to see the argument for that in order to comment. Nyquist criteria is well established for band limited signal and in case of telescope aperture we have band limited signal with highest frequency depending on aperture size. https://www.telescope-optics.net/mtf2.htm Maximum frequency is 1/lambda * F_ratio so we should sample at twice that frequency - or 2/lambda * F_ratio. If you rearrange above equation focal_length = 3 *aperture * pixel_size / wavelength * 1.22 => 1 / pixel_size = (3 / 1.22) * aperture / (focal_length) * wavelength = (3 / 1.22) * 1 / f_ratio * wavelenght Here we see that instead of 3 being quotient - 3/1.22 is used (again in error). This is because above formula is based on Airy disk size in spatial domain and not MTF in frequency domain. Just simply wrong application of Nysquist. I came to correct value using above formula and experiment with actual data, so indeed sampling rate should be 2/f_ratio * wavelength. As far as I can tell PIPP has option to bin in software: and I would certainly use that to calibrate my recordings and also do the binning. It can do both dark and flat calibration, and I would recommend using SER file format and 16 bit for recording and processing (in fact I would go with 32bit but not sure if calibration is done in 32bit in PIPP).

First of all - that calculation is not quite correct. It is very close to what it should be, but wrong assumptions were used - like that x3 being x3 for Nyquist criteria - like it is somehow "better" than x2 that Nyquist criteria says or even explanation that I've heard - well this is 2d case so one ought to use x3 instead of x2. Anyway, proper F/ratio for pixel size is 0.8133... times that value (we can go into details but it's 2.44 instead of 3). You want F/8.85 to be properly sampling. Now, your scope is 480mm F/6 and Quark has x4.2 telecentric lens - this means that effective F/ratio is F/25.2. If you use ASI290 regularly, you will be oversampling by large amount. However, not all is lost. Since you have F/25.2 system, let's see if we can do something about it. What would happen if you used camera with x3 larger pixel size instead of ASI290 native pixel size? Well, you would need 3 x F/8.85 = F/26.55 system for optimum sampling rate. That is very close to F/25.2 that you already have so you would be very close to optimum solution. How on earth would you get x3 pixel size on such camera? Well - there is simple solution, bin your pixels 3x3 in software. There you go, almost optimum sampling rate. But hold on, there must be some sort of catch? ASI174 is certainly better with its large pixel size? There is a catch, but let's see how much it matters. When doing software binning, camera will have higher read noise. In case of 3x3 bin, read noise will increase x3. ASI290 has read noise of ~1e at high gain (and you should be using it), so overall after x3 bin it will have pixel equivalent of 8.7um and read noise of ~3e. ASI174 on the other hand has 5.86um pixel size and read noise ~3.5e. ASI290 will have larger pixel / better matched to F/25.2 of your system and lower read noise. You only need to bin it x3 in software. If you want to go with bigger scope - do this math again on a bigger scope and see what is suitable combination. In fact, I think that for bigger scope, you don't really want regular Quark - you want Quark combo as with it you can use your own telecentric lens and aperture masks to get needed F/ratio - both for proper sampling rate and also for best filter operation.

If you are interested in planetary observing - then go for Mak127. These are two very different scopes. Evostar is very large and won't be Eq3 class mount is simply not large enough to carry it. Scope is large and heavy and it is best suited for DSO observing - open star clusters in particular. Evostar will show quite a bit of chromatic aberration on bright targets. Mak127 is well suited for Eq3 class mount. If you are interested in planets - consider adding a tracking motor, it makes quite a bit of difference to observing experience for planets (no need to constantly adjust position of the scope). Focuser on Mak is 1.25" and on Evostar it is 2". On Mak, back opening is small and you can't use 2" eyepieces without vignetting (you can change visual back for 2" one but it wont make much difference in how much wide the scope can go). For planetary observing, you really don't need 2" eyepieces as planets are small.

M33 is going to be better placed later on. I'm a bit more south at 45N but just for argument sake - at the moment M33 is at a 48 degrees altitude at midnight. If I wait another one and a half months before I go for it - it will be at 75 degrees altitude at midnight - that is only 15 degrees shy of zenith (24th of October). Stellarium is your friend - take your regular imaging time - split it in two - this will be your marker (for example if you image between 10pm and 2am - it will be midnight, but it can be earlier, especially in winter when it gets dark really early, however - do bare in mind that light pollution changes with time as well - people turn off lights and shops close after some time in the evening). Plan to image target that is crossing meridian very near your "marker" time. This will give you time when the target is highest in the sky. Of course, adjust for Moon cycle and weather - if you have window before or after - move your "marker" accordingly - no reason not to start at 9pm and finish by 1am of if you can stay up late - start at 11pm and finish at 3am - in either case, you get where this is going . This can also be a guide for selecting targets - plan to image tonight? Again go to Stellarium and see what objects cross meridian around mid of your regular session - choose one of them that you like and then "adjust" session time so that target crosses meridian half way thru the session.

Then it is simple - RA direction is "up/down" and DEC direction is left right. Star elongation is in RA direction - definitively periodic error. If you are already close to guiding - just go with it and it will sort these problems. Another hint - since you are in light polluted area - don't shoot things near horizon. Shoot what is directly above you at zenith or at least high in the sky (like 60 degrees of altitude and above). This is the darkest part of the sky and also there is atmosphere the least thick so it will block the least amount of light from target. This will give you best images. Leave targets that are low down at horizon - either for trips to dark locations or even better - trips to abroad. Shoot targets that you can from your location.

Saturation is over exposure in regular photography - when some parts turn out white. In fact, you can have over exposure in astrophotography without signal going white - these will be border line cases - when one channel is saturated / over exposed and others are not (because they are not balanced in raw and one channel can be and usually is stronger than than others). You can also recognize this as histogram clipping to the right, but this is severe case, you can have saturation in bright regions without histogram going all they way to the right. For example this image: core of M42 is very bright and easily saturated. It just turns white in post processing without any features. You either need to be sure how you oriented your camera or you need to plate solve the image (astrometry.net for example). If you have refractor and you place your camera "vertically" or "horizontally" when scope is at home position - looking at Polaris, then RA/DEC are aligned with the image - so RA is either horizontal or vertical. With Newtonian it's not that easy because of secondary mirror can be at any orientation and will add to rotation of FOV. You can also check this when at the scope - if when slewing telescope in one axis (either RA or DEC) stars and objects move horizontally or vertically - you have aligned your camera and RA is either horizontal or vertical (which ever way things move when you slew in RA direction). PHD2 will solve this if you are guiding, but I believe you said you are not guiding yet. Once you start guiding - both this and polar align error are fixed by guiding - that is the main point of guiding - to fix these two issues. If you are still not guiding nor intend to belt mod your mount - you should try Periodic Error Correction. I have HEQ5 mount as well, but have Syntrek version, not Synscan. My hand controller is simple one and does not support PEC (Periodic error correction), however I use my mount via EQMod and computer and EQMod supports PEC, so I use it like that. I'm not 100% sure, but you hand controller could support PEC - so you need to check your manual for PEC training section. Let me see if I can google that for you. https://inter-static.skywatcher.com/downloads/Synscan_V4_Hand_Control_Manual_SSHCV4-F-161208V1-EN.pdf If your controller is V4 - then take a look at manual at page 42. You'll need high power eyepiece - preferably one with cross hair and some time at your scope. Procedure is rather simple, just set scope to track and then issue corrections via hand controller for some time. After you'll have periodic error correction programmed. Do be warned - you might need to park your scope after each session to retain this PEC information or you'll need to record it again next time (read the manual for details - I know this from my HEQ5 and EQMod and PEC there).

As long as you don't get saturation in signal from your target - you are good. Periodic error. Stock Heq5 pro can have around 30-40" P2P periodic error. Period is about 10 minutes, so in 5 minutes mount can travel 30-40 arc seconds. In two minutes that will be around 12"-16". What is your imaging resolution? If you are imaging at 2"/px - that will make 6px - 8px trails. I'm reading about 9px trails in this particular sub. Of course, periodic error is not uniform - it is more sine like (if you are lucky, or very complex if you are unlucky), so some frames will have larger trailing and some smaller (if any). There are several things that you can do: - PEC training (EQMod might be required as I'm not sure stock HEQ5 supports this) - Belt modding - this reduces P2P periodic error (to less than 10" or there about). - Of course, guiding. Just to test if this is indeed PE - look if elongation is oriented in RA direction.

No, with ASI174 and 5.86um pixel size, you want around F/23 (to be precise, for green at 510nm it's exactly F/23). I would rather go for F/20 than F/25 in this case. https://www.firstlightoptics.com/explore-scientific-eyepieces/explore-scientific-2x-3x-5x-barlow-focal-extender-125.html

Low budget option - very good range of focal lengths available: https://www.teleskop-express.de/shop/product_info.php/info/p154_TS-Optics-7-mm-Planetary-HR---1-25--Eyepiece--58---fully-multi-coated.html High performance but narrow field of view (not good if your scope does not have tracking mount - you need to nudge it more frequently and that distracts from viewing), also plenty of eye relief: https://www.firstlightoptics.com/vixen-eyepieces/vixen-slv-eyepieces.html Excellent performers with wide field: https://www.firstlightoptics.com/explore-scientific-eyepieces/explore-scientific-82-degree-series-eyepieces.html There are only a few focal lengths available like 4.7mm, 6.7mm and 8.8mm that could be considered planetary on fast scope. Maybe think of adding telecentric lens like this one: https://www.firstlightoptics.com/explore-scientific-eyepieces/explore-scientific-2x-3x-5x-barlow-focal-extender-125.html x2 1.25" version (you won't need 2" version nor more power). In fact, in most cases you won't need over x200 power, which you can get with 6mm eyepiece. Atmosphere is limiting factor. I always prefer single eyepiece vs barlow + eyepiece, but sometimes people find barlow + eyepiece sharper and easier to use. If you want the best planetary performance (at a cost), have look at perhaps these (they are 50% over your top budget per piece): https://www.firstlightoptics.com/tele-vue-eyepieces/tele-vue-delite-62-degree-eyepieces.html

I can't be totally sure how much belt mod itself made a difference because I tuned my mount as well when I did the belt mod. I had to do that because one of bearings had a crack and needed to be replaced so I changed all of them for high quality SKF bearings. I do know that periodic error went considerably down, backlash improved dramatically and yes, noise went down - but that was not something I was overly concerned with. After all the mods and improvements, I went from >1" RMS guiding to ~0.5" RMS guiding, so that is quite an improvement, but I can't say how much is it down to belt mod itself and how much is due to other changes.

That is not quite true for imaging purposes. It is still 6" scope, but with more contrast loss than unobstructed scope. You need greater SNR to restore those frequencies. ASI120 is not cooled either - none of those planetary cameras are (there were few models there were cooled but they stopped making those - I still have ASI178 that is cooled). In any case, there is no point in cooling for planetary and guiding purposes, and you are right - 2x2 bin will increase pixel size. There are a few options in PHD2 - among them is 2x2 average to reduce noise - which is essentially the same as binning. Sometimes it is better to have smaller pixels for guiding - better precision. Sort of is, but you can put quite a bit of kit on HEQ5. I image with 8" RC scope on HEQ5 and manage 0.5" RMS guiding, but mount is modded quite a bit (berlebach tripod, geoptic saddle plate, belt mod, tuned, etc ...). I used to image with 8" F/6 newtonian and guide scope on HEQ5 - now that was pushing it - but it sort of worked.

I purchased M8 hex key bolt to replace Star Adventurer wedge clamping one because I put AzGti head on it and it won't turn in RA (former azimuth) because of that clamping screw. Nice little and necessary mod - cost me total of about 10 euro cents (0.1e). I also checked numerous times status of my shipment from FLO - last update still from 26th - "Item leaving UK" at LANGLEY HWDC. Does this count? It is for imaging rig - T2-Canon EOS adapter (eos lens to T2 astro camera - that I'll put on AzGTI).

Are you sure? I think you can specify "extras" with your order - like type of coatings, barrel type, materials used and so on...

No such thing as HEQ6. If you are referring to EQ6, then you won't really see any improvement in precision over HEQ5, and you are still not close to weight limit of your mount. Step up from this mount could be CEM60 (no longer produced for some strange reason). Yes, dedicated cooled astro camera would be my first choice, maybe OSC one if you are used to that sort of framework and don't want to "shuffle" things too much. If you want to try planetary, then that will probably be cheapest upgrade - switch guider camera for planetary camera (and also guider camera) and purchase SW 6" F/8 newtonian scope. Alternatively, if you want really good optics - go for Orion Optics UK VX6L with upgrade to 1/10PV (if budget allows and you really want to do planetary / lunar - go for OO with 1/10) RC 6" is not the best for planetary work only because of massive central obstruction, but in reality can give you decent planetary images. Here is Jupiter with RC8": Just changing your current guider camera for planetary / guider with USB3.0 - something like ASI120 usb 3.0 version or maybe more serious camera like ASI224 should give you decent results with your scope. Another cost effective upgrade, if you have not done that already is belt mod for HEQ5.

There could be actual reason for that, but TS could also be trying to earn more on same items. Many of those eyepieces are manufactured by same company, but may not be to the same level of quality or from same materials. I'm not saying that with BST Starguiders vs N-EDs is this case, but here are some such cases: https://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-uwa-planetary-eyepieces.html vs https://www.teleskop-express.de/shop/product_info.php/info/p154_TS-Optics-7-mm-Planetary-HR---1-25--Eyepiece--58---fully-multi-coated.html Again, TS version are more expensive but I think generally believed by many to be the best version of this planetary design (originally TMB) currently being produced. Then we have these: https://www.teleskop-express.de/shop/product_info.php/info/p4923_TS-Optics-Ultra-Wide-Angle-Eyepiece-6-mm-1-25----66--field-of-view.html vs these: https://www.svbony.com/1-25-inch-66-degree-eyepieces/#F9157A They should be the same design, but are coatings and finish of eyepieces and quality control the same? I don't really know.

In general, accessories that you get with such scopes are just to get you going. Diagonal and eyepieces are first to be replaced. Red dot finder is not that bad and if you need light weight finder - it is actually very usable although might not be the best mechanically (but you don't use it that much so it bothers you). Same goes for optical finders - 5x24 - usually plastic item, but 6x30 can be decent and 8x50 being quite nice unit, but often get exchanged for RACI versions.

Here is comparison of FOV with Canon 550D and these two scopes (72ed is with dedicated x0.85 FF/FR). So it's about x2 larger FOV. You can check FOV for other targets here: https://astronomy.tools/calculators/field_of_view/ 72ED is very nice scope for really Grab'n'go kind of setup - on a small mount like AzGTI turned into EQ mount (eq modded - very simple mod, just a firmware and wedge + counter weight): AzGti is very nice small portable mount, and I have good experience with it - here is setup that I used recently (but I'll replace DSLR with dedicated astro camera and lens very soon): In the mean time I acquired proper wedge, but counter weight is still DIY . You don't need to use it on very large tripod - it comes with nice aluminum light weight tripod, but you can also use good photo tripod if you like.

Weight wise, small frac and 130PDS are similar - but not in bulk/volume. Maybe these two images will help put things into perspective: In first image we see 130PDS and ST80 F/5 as guide scope, and ST80 is larger than 72ED. In second image you can see size of 72ED in hand. Another thing to consider is what you want to image with it? 130PDS is 650mm of FL, and 72ED is 420mm FL and with FF/FR - probably even less - maybe a half that of 130PDS. This means that 72ed will likely offer twice the field of 130PDS but half the sampling rate of 130PDS with the same camera. Question is - do you want wider field like that. Final question is - do you prefer working with newtonian or refractor scopes for imaging - there are diffraction spikes and collimation and in general some people like hassle free performance of refractor (provided FF/FR spacing is right and there is no tilt).

Having both 150PDS and 130PDS seems a bit redundant as there is very small difference between the two. 750mm FL vs 650mm FL - which also implies that overall length of OTA is only about 10cm of difference. Aperture change is 20mm, so again - very small difference in size of OTA, and light collecting power is not that different, only 33% more. In any case - no telescope could help call setup with EQ6 - grab'n'go - however small.

I would not call it special by any means. In terms of performance, it is probably very similar to IMX178 present in ASI178 and similar models. 1/1.8 sensor, high QE at 80%+, low read noise at about 1-1.5e. 4.1um pixel size is nothing special - use ASI178 with 2.4um pixels and bin them and you'll get 4.8um pixels - even more "sensitive". Canon one only works at 60fps - that makes it less suitable for planetary imagers.