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Is your 10" RC truss design or solid tube?

I'm not sure I'll build a prototype of that as I'm not overly interested in having artificial scope. I was just interested in principle of operation. However, I am interested in slightly different thing that is in principle the same as above, except it allows for wide audience to observe at the same time. Everything would be the same, except the output would not be on high density display housed in OTA but rather to a pico projector. That way we could have image projected on projection screen - enough for small audience of up to 10-15 people. As for stacking software, I'm aware of Jocular, not sure where it is hosted as open source project. I have all the algorithms needed and some fancy additional ones In fact, I would be happy to share them if you want. Here is an example of background detection and background removal: Here is one image someone here on SGL posted (I found it in my downloads section) that has very strong gradient: First iteration step estimated background: Gradient: After removal of gradient in first iteration we can do few additional iterations for better results, so second iteration background is: Additional gradient: Final image after two iterations: Algorithm models background as linear feature, although it can easily be adopted to work with higher order polynomials.

Happened to me only once - very damp conditions, but I did get some dew on secondary.

Depends on a target. There are two different types of targets - extended targets and point sources. Any target is point source provided it is sensed by more than one receptor. This holds for both visual and imaging - if target is spread over single pixel or single "visual cell" (here it could actually be few real cells - not sure how this works in combination with brain). In simple terms - point source is a star that has not been resolved into airy disk. Everything else is extended source. Extended source keeps the same brightness if you increase aperture but keep exit pupil the same. In order to understand why - one just needs to see condition to keep the same exit pupil with increasing aperture. Exit pupil is image of aperture and its size is size of aperture divided with magnification. If we increase aperture, to keep the exit pupil constant, we need to increase magnification by the same amount. If we have 100mm scope and 1mm exit pupil, this means that we are at x100 magnification. If we increase aperture to 200mm, in order to keep 1mm exit pupil, we need to change magnification to x200. This change in magnification means that light on sensor (eye or camera sensor) is spread around more, and in fact - it is now on 4 times larger surface (if we increased aperture and magnification by x2). Surface of aperture changed by factor of x4 and also area that light gets spread over increased x4 - brightness per unit sensor area remains the same. We see same brightness and sensor captures same number of photons per each pixel. With point sources - it does not get spread and it stays "in the same place", since image is not resolved. With point source brightness is increased by increase of aperture - up to moment when point source gets resolved and is no longer point source.

No, actually, this is not going to be tutorial how to do that, although it could develop into one over time - open source kind of eVscope. Here is the idea and list of parts: 1. 114mm F/4.5 Newtonian 2. Cheap 2" Coma corrector like SW 2 element x0.9CC or Baader MPCC 3. 2" helical focuser 4. Raspberry PI 5. Az-GTI mount 6. 50mm finder scope 7. 32mm plossl eyepiece 8. PVC pipe 9. Your mobile phone Scope is mounted on AzGti and stock focuser is replaced with 2" helical focuser model (don't throw away stock focuser). This step will probably need 3d printed base for helical focuser and some tweaking of the telescope. Rpi will operate mount and camera and stacking software which will be accessed via phone. All of this up until now is just regular EEVA. Now comes the optical part - I just tested it and it works very well. We just need re-imaging lens and 50mm finder scope works very well. 32mm Plossl has about 27mm field stop. Decently sized phone (I'm using Xiaomi mi a1) with 1080p display will have about x3 that size in height and 1080 pixels to display. This is something like x3 less resolution than human eye can resolve and indeed - one can almost see pixels, but point is to "shrink" phone by width to fit into field stop. If we place our phone at appropriate distance from 50mm lens and use eyepiece on the other side again at appropriate distance (lens formula 1/phone_distance + 1/eyepiece_distance = 1/focal_length_of_finder and also we account for magnification, or rather minification factor) we will actually get very nice view of the phone screen filling the FOV. All we need is some sort of tubing and means to mount everything so it is on optical axis. Do remember to unscrew finder eyepiece first before. I just did a test holding everything in hand and I managed to get very nice, almost aberration free image (some shake and tilt was inevitable with hand held configuration). There you go - EEVA "scope" - complete with refractor looking scope and focuser and real eyepiece. For those that want more quality - high dpi OLED screen for raspberry pi might be solution. All we need is stacking software that works with INDILIB or INDIGO. Of course, one does not need to use above configuration (which is one used by eVscope) and is free to use whatever EEVA setup is already using - point is just to display image on small high DPI device and use 50mm lens and eyepiece to view it.

Hi, yes, it's related to bayer matrix. Under ideal conditions - one would do twice sampling rate and then split matrix into RGB components where there would be twice as much G subs then R and B. Processing would then be much like mono + filters. Alternative is to do full processing at twice sampling rate and then reduce image size by factor of 2 in the end for sharpest results (many people don't do this and tend to leave their images over sampled which results in blurry looking image - I don't like it but most don't seem to mind it).

You seem to have 15x70 binoculars? That is not far away from ST80 experience. You'll be able to change magnification but only use one eye for observing. Image will be slightly brighter but not by much. It should also be sharper and depending on eyepiece used - larger AFOV.

Only issue I've found with short refractors on this mount is observing near zenith. I had ST102 and TS80 F/6 apo mounted on AZ4 and both would sort of hit the mount with focuser knobs when looking straight up. If that is concern to you - check how would 130mm tube fit that mount by using some sort of mock up (there is a chance you would not be able to look at zenith targets with wider OTA as it would hit the mount head). This image illustrates potential problem - just imagine OTA pointing straight up - it would definitively hit mount base.

Primary mirror is fixed with this model at correct distance and generous back focus is just feature of these scopes to allow for variety of attachments (2" diagonal, field flatteners and reducers, oags, filter wheels and so on).

I had the same dilemma, but image names solved it for me. Top, blurry one, ends with "Capture17_04_201423_13_08z.png" and there is mention of previous result of about 5 years ago. Bottom sharp one is titled MarsBestsofar.jpg - I figured that must be recent image we are talking about.

Just love that this has been edited

I don't see why not, Sony E-mount has 18mm of flange distance, so you need adapter that is at most 11.5mm long (optical path) and you should be fine.

It is extremely difficult to get such focused light on sensor from light leak - it needs to be focused by optical element or diffracted of an edge in the system.

I'm now getting 6932.736 Just to make sure there is no error, let's do it step by step CC: (93.25 x 93.25 - 34.25 x 34.25) x 0.96^2 = (8695.5625 - 1173.0625) * 0.96^2 = 7522.5 * 0.96^2 = 6932.736 Mak150 to CC = ~25% increase in light CC to C8 = ~25% increase in light This time it sits pretty much in between the two.

I just came across very important point for 8" CC if it is indeed stopped down to 7.3". Secondary obstruction is 68mm and primary is 186mm. That makes secondary obstruction almost 37% rather than 33%.

https://www.orionoptics.co.uk/VX/vx6-6l.html OO UK say that their VX6L weights 5kg which is 11 pounds.

I'm only mentioning it because it was on the list of possible scopes in the initial post. In my view, except for the high end ED refractor (or triplet) which is not considered both because of price and bulk, this scope will give best views of the lot. Every other design is compromise in some respect.

It's actually lighter than that - only 11.9lbs. If length is not an issue, I would still consider 6" F/8 planetary newtonian first. 1/10th wave optics and less than 25% central obstruction is bound to give views that are refractor like.

Not if you use that 60mm F/5.9 or get decent Samyang lens. I've got ASi178mcc - color cooled version and can't wait to test out newly acquired 85mm F/1.4 with it.

You probably did not notice that there is finder scope in that image as well

RC is also corrected for coma and has only astigmatism left. It has large corrected field with very small amount of curvature. It is good scientific instrument (most professional scopes are RCs) and good for imaging. Not as good for visual because central obstruction is usually much larger. It has two hyperbolic mirrors. In this particular case it is F/8 scope suited to DSO imaging. CC in this case is F/12 and central obstruction is smaller - good for visual and imaging of planets.

It should. It is about 6Kg in weight (FLO lists it at 6.3Kg while TS has it at 5.4Kg) so it is not one of the lighter scopes. Add diagonal, eyepiece and finder scope and you could easily push past 7Kg. Since it is short tube it might work without too much trouble, although I've seen just few quotes that Eq3-2 can carry 7kg and most of the time it is listed at 5kg. Maybe consider EQ5 after all as it will be much more stable platform. CC are completely corrected for spherical aberration, so are SCT and MCT. SCT can have spherical aberration because its correction depends on distance between mirrors and since they focus by moving primary mirror - there can be more or less spherical at certain focuser position. CC does not suffer from this and it should be completely free from spherical aberration. It does have some amount of coma and astigmatism and here are expressions for those: As a comparison here is coma of Newtonian telescope: D is diameter of aperture F is F/ratio of the scope. Expression for coma is the same and CC has as much coma as F/12 Newtonian - very small amount of it. In comparison, 8" F/10 SCT will have coma similar to F/6 Newtonian. All above info can be found here: https://www.telescope-optics.net/

Drawer is really not practical for planetary as one needs to change filters rapidly as not to loose any imaging time (planets rotate and one does not have very long window for imaging). This is why I linked to EFW. Maybe even regular manual filter wheel could be used, but I would not use drawers for planetary. DSO imaging is different - you don't loose much of imaging time if you spend one minute on filter change there.

I vote for this one, although, if Mak150 is too heavy - I think 6" F/8 will be as well and much bulkier.

I use baader RGB filters for DSO imaging, but I think for planetary I would go with cheapest filter set as you don't need to worry about faint reflections / halos and such. As for filter wheel - I don't have one, I use filter drawer, but I did get my eye on one of these since I'll be making permanent setup / obsy next year: https://www.firstlightoptics.com/filter-wheels/zwo-mini-electronic-filter-wheel-efw-5-x-125-or-5-x-31mm.html It's not that expensive and has positive reviews. I did not do much research but you want your EFW to be repeatable - filters always in the same position (so you can reuse flats) and there is no light leak.